Marqibo (vincristine sulfate liposomes injection) Briefing Document, Advisory Committee Meeting

Transcription

1 Marqibo (vincristine sulfate liposomes injection) MARQIBO (VINCRISTINE SULFATE LIPOSOMES INJECTION) FOR THE TREATMENT OF ADVANCED RELAPSED AND/OR REFRACTORY PHILADELPHIA CHROMOSOME NEGATIVE (PH-) ADULT ACUTE LYMPHOBLASTIC LEUKEMIA SPONSOR BRIEFING DOCUMENT FDA ONCOLOGIC DRUGS ADVISORY COMMITTEE MEETING MEETING DATE: March 21, 2012 AVAILABLE FOR PUBLIC DISCLOSURE WITHOUT REDACTION Page 1

2 Marqibo (vincristine sulfate liposomes injection) Table of Contents List of Tables... 5 List of Figures... 7 List of Abbreviations... 8 EXECUTIVE SUMMARY Introduction Relapsed and Refractory ALL: Current Treatment Options and Outcomes Overview of ALL Front-Line (First-Line) Treatment of Ph- Adult ALL Reported Outcomes in Relapsed and Refractory ALL First Relapse Therapy Experience Second Relpase and Refractory Therapy Experience Overview of Vincristine Vincristine-Induced Neuropathy Composition, Nonclinical Overview, and Clinical Pharmacology of Marqibo Composition of Marqibo Nonclinical Overview Clinical Pharmacokinetics of Marqibo Bioavailability Distribution Metabolism Elimination Vincristine PK: Marqibo vs. Standard Vincristine Formulation Special Populations Overview of Marqibo Clinical Development Program Regulatory History Clinical Dose Selection and Strategy for Dose Reduction to Limit Toxicity Overview of Studies HBS407 and VSLI-06 - Efficacy Component Study HBS Study Design Subject Population Selection and Exclusion Criteria Dose Reductions and Temporary Suspension of Dosing Page 2

3 Marqibo (vincristine sulfate liposomes injection) Subject Follow-up and Schedule of Visits and Procedures Primary Endpoint Secondary Endpoints Analysis Populations Statistical Methods Clinical Efficacy Demographic Baseline Characteristics Disposition and Dosing Efficacy Results Clinical Response Secondary Endpoints Subgroup Analyses of Efficacy Study VSLI Study Design Clinical Efficacy Demographic and Other Baseline Characteristics Dosing Efficacy Results Historical Salvage Response Rates Third-Line Therapy of ALL Second-line Therapy of ALL Clinical Safety Description of the Safety Populations and Extent of Exposure Adverse Events in Studies HBS407 and VSLI All Adverse Events AEs Leading to Discontinuation or Dose Reduction Death SAEs Deaths and SAEs across the Remaining Marqibo Experience HBS VSLI Clinical Laboratory Findings Hematology ALT, AST, Alkaline Phosphatase, and Bilirubin Creatinine Other Analytes Page 3

4 Marqibo (vincristine sulfate liposomes injection) 6.5 Vital Signs and ECG Findings Special Safety Topics Neuropathy Infections Cardiovascular Hepatobiliary Renal Post-approval Commitment Study of Subjects 60 Years of Age with Newly Diagnosed ALL Risk Management Plan Benefit/Risk Conclusion REFERENCE LIST APPENDIX A CLINICAL DOSE SELECTION AND STRATEGY FOR DOSE REDUCTION TO LIMIT TOXICITY IN STUDY VSLI APPENDIX B DOSE REDUCTION/DELAY SCHEMA IN STUDY HBS APPENDIX C HISTORICAL COMPARISON APPENDIX D SUBJECT NARRATIVES APPENDIX E SUPPLEMENTAL DATA TABLES APPENDIX F Synopsis for Post-Approval Commitment Study TTX Page 4

5 Marqibo (vincristine sulfate liposomes injection) List of Tables Table 1. Prognostic Predictors for Relapse Following Front-Line Therapy...27 Table 2. Vincristine Levels in Tumor-bearing Mice* Administered Standard Vincristine vs. Marqibo Table 3. Summary of Total Vincristine PK Parameters after Marqibo Administration...40 Table 4. Comparison of Coefficient of Variance (%) for Various PK Parameters for Marqibo and Other Liposomal Drug Products Approved in the US, Canada, and Europe...43 Table 5. Summary of Total Vincristine PK Data Following Marqibo and Standard Vincristine Administration in Adults...45 Table 6. Summary of Studies HBS407 and VSLI Table 7. Demographic Characteristics: Study HBS Table 8. Baseline Characteristics: Study HBS Table 9. Prior Anti-Leukemia Therapy: Study HBS407 (ITT)...60 Table 10. Summary of Dose Modifications in Study HBS407 (ITT)...61 Table 11. Clinical Response Assessment Study HBS Table 12. Prior Therapies of Subjects Who Achieved CR or CRi (IRRC Assessment) - Study HBS Table 13. Complete Response by Baseline Demographic and Disease Characteristics or Prior Therapy Study HBS Table 14. Principal Investigators Assessment of Tumor Response: Study VSLI-06 (ITT Population)..71 Table 15 Studies Identified with Response Rates in Adult ALL...72 Table 16. Percent of Patients by Number of Risk Factors that Adversely Affect Survival: MDACC vs. HBS Table 17. Demographic and Other Characteristics ITT Subjects in Study HBS407 and 56 Patient O Brien Cohort...77 Table 18. Results of Single- and Multi-Agent Therapy for Advanced Adult ALL...78 Table 19. Results of Single-Agent Second-Line Therapy for Adult ALL...79 Table 20. Demographic Characteristics (Study HBS407 and Study VSLI-06, N=101)...81 Page 5

6 Marqibo (vincristine sulfate liposomes injection) Table 21. Subjects by Marqibo Dose (All Screened Subjects)...82 Table 22. Overall Summary of Adverse Events (Study HBS407 and Study VSLI-06, N=101)...84 Table 23. Adverse Events Grade >= 3 Occurring in >= 5% of All Subjects by System Organ Class and Preferred Term (Study HBS407 and Study VSLI-06, N=101)...86 Table 24. Adverse Events Leading to Study Drug Discontinuation (Study HBS407 and Study VSLI-06, N=101)...90 Table 25. Summary of Deaths (Study HBS407 and Study VSLI-06, N=101)...94 Table 26. Serious Adverse Events Occurring in >= 2 Subjects by Preferred Term (Study HBS407 and Study VSLI-06, N=101)...97 Table 27. Abnormal Vital Sign Results Observed Any Time During the On-Treatment Period (Study HBS407 and Study VSLI-06, N=101) Table 28. Neuropathy Adverse Events of Grade >= 3 Severity (Study HBS407 and Study VSLI-06, N=101) Table 29. Any Neuropathy-Related Serious Adverse Events (Study HBS407 and Study VSLI-06, N=101) Table 30. Line of Therapy and Prognostic Category Study HBS407 vs. Historical Comparator Study Table 31. Demographic and Other Characteristics ITT Subjects in Study HBS407 and Ph- Adult ALL Subjects from Historical Comparator Study Who Received Single-Agent (Non-Marqibo ) Third-Line Therapy Table 32. Treatment Outcomes ITT Subjects in Study HBS407 and Ph- Adult ALL Subjects from Historical Comparator Study Who Received Non-Marqibo, Single-Agent, Second Salvage Therapy Table 33. Marqibo Clinical Studies Contributing to the Summary of Clinical Safety (Reference Table of Marqibo Clinical Studies from 1993 to 2011) Table 34. Vincristine-Associated Neuropathy AE Search Terms (MedDRA Preferred Terms) Page 6

7 Marqibo (vincristine sulfate liposomes injection) List of Figures Figure 1. Stages of Ph- Adult ALL and Available Patients in the U.S Figure 2. Cancer and Leukemia Group B (CALGB) Protocol 8811 Schematic...27 Figure 3. First Relapse and Refractory Therapy Scenarios...29 Figure 4. Second Relpase and Refractory Therapy Scenarios...30 Figure 5. Concentration of Vincristine in Tissues Following Standard Vincristine vs. Marqibo Administration...35 Figure 6. Anti-Tumor Activity of Marqibo by Dose...37 Figure 7. Anti-Tumor Activity of Marqibo vs. Standard Vincristine...38 Figure 8. Mean Total Vincristine Plasma Concentration-Time Profile (HBS407, N=13)...42 Figure 9. Plasma Concentrations of Total Vincristine a Over Time Following Single Dose Marqibo 2.0 mg/m 2 and Standard Vincristine...44 Figure 10. HBS407 Study Schema...51 Figure 11. Kaplan-Meier Plots of Overall Survival Study HBS Figure 12. Design Schematic for Study TTX Figure 13 Summary of Efficacy and Safety in HBS Figure 14. Dose Reduction/Delay Schema for Marqibo -Related Nonhematologic Toxicities in Study VSLI Figure 15. Dose Reduction/Delay Schema for Study Drug-Related Nonhematologic Toxicities in Study HBS Figure 16. Third Line of Treatment Scenarios in O Brien Review of Adult ALL Page 7

8 Marqibo (vincristine sulfate liposomes injection) List of Abbreviations Abbreviation AE ALL ALT ANC AST AUC BM BMB BP BSA CBC Chol CI Cl C max CNS CR CRi CRp CSR CTCAE CV CYP DBP DLT ECG ECOG EFS EMA FDA GVHD HI HPLC HSCT IND Definition Adverse event Acute lymphoblastic leukemia Alanine transaminase or alanine aminotransferase Absolute neutrophil count Aspartate transaminase or aspartate aminotransferase Area under the curve Bone marrow Bone marrow blast response Blood pressure Body surface area Complete blood count Cholesterol Confidence interval Clearance Maximum concentration Central nervous system Complete remission Complete remission with incomplete blood count recovery Complete remission without full platelet recovery Clinical study report Common Terminology Criteria for Adverse Events Coefficient of variation Cytochrome P450 Diastolic blood pressure Dose-limiting toxicity Electrocardiogram Eastern Cooperative Oncology Group Event-free survival European Medicines Agency Food and Drug Administration Graft-versus-host disease Hematologic improvement High performance liquid chromatography Hematopoietic stem cell transplantation Investigational New Drug Page 8

9 Marqibo (vincristine sulfate liposomes injection) Abbreviation Definition IRRC Independent Response Review Committee ITT Intent-to-treat IV Intravenous IVR In vitro IWG International Working Group K-M Kaplan-Meier LLOQ Lower limit of quantitation MedDRA Medical Dictionary for Drug Regulatory Activities MDACC M.D. Anderson Cancer Center MPS Mononuclear Phagocyte System MRD Minimal residual disease MTD Maximum tolerated dose NDA New Drug Application NR No Response ODAC Oncologic Drugs Advisory Committee OR Overall response OS Overall survival PD Progressive disease Ph- Philadelphia chromosome negative Ph+ Philadelphia chromosome positive PI Principal investigator PK Pharmacokinetics PR Partial remission QTcB Corrected QT interval using Bazett s formula QTcF Corrected QT interval using Fridericia s formula SAE Serious adverse event SBP Systolic blood pressure SD Stable disease SM Sphingomyelin SOC System organ class SPA Special Protocol Agreement t 1/2λ0 t 1/2λ1 T max ULN US V ss VSI Elimination half-life for initial slope (with biexponential decline) Elimination half-life of the terminal slope (with biexponential decline) Time to maximum concentration Upper limit of normal United States Volume of distribution at steady state Vincristine sulfate injection VSLI Vincristine sulfate liposomes injection (Marqibo ) Page 9

10 Marqibo (vincristine sulfate liposomes injection) Abbreviation WBC Definition White blood cell (count) Page 10

11 Marqibo (vincristine sulfate liposomes injection) EXECUTIVE SUMMARY Talon Therapeutics submitted a New Drug Application (NDA) to the U.S. Food and Drug Administration on July 12, 2011, seeking accelerated approval for Marqibo (Vincristine Sulfate Liposomes Injection, VLSI; hereafter referred to as Marqibo ) for the treatment of patients with Philadelphia chromosome negative (Ph-) adult acute lymphoblastic leukemia (ALL) in second or greater relapse or whose disease has progressed following two or more lines of anti-leukemia therapy. There are no approved or standard-of-care treatment options in this patient population, which includes both advanced, relapsed B-cell lineage and T-cell lineage ALL. In Study HBS407, Marqibo monotherapy increased the rates of complete remission with (CR) or without (CRi) complete blood count recovery (i.e., CR+CRi), durable response, and overall survival as compared to historical controls. Overview of ALL and Unmet Medical Need Adult ALL is one of the rarest malignancies, with only approximately 2,000 new cases diagnosed annually in the U.S. Of these, approximately 1,400 are Ph- Adult ALL (1,100 cases B-lineage and 300 cases T-lineage) (Cancer Facts and Figures 2010 ACS). Based on published treatment response rates and treatment-related mortality rates, each year in the U.S. approximately 840 patients relapse from a first remission or are refractory to front-line therapy and are in need of a second line of therapy, referred to by some as a first salvage therapy 1. Fifty-five percent (55%) of these (~ 458 patients) will relapse a second time or be refractory to second-line therapy, with worsening prognosis, decreased survival, and a need for a third line of therapy (Tavernier et al 2007, Thomas et al 1999, O Brien et al 2008). The 1 The term salvage therapy is used by MD Anderson Cancer Center investigators to discuss treatment of adult ALL patients who are refractory to treatment or after they relapse (Thomas et al 1999, O Brien et al 2008). Patients eligible for first salvage therapy are those who are refractory to front-line induction therapy or who achieve an initial remission but subsequently relapse during or following consolidation or maintenance therapy. For these patients, first salvage constitutes a second line of therapy. If hematopoietic stem cell transplantation (HSCT) has been performed in first remission and prior to the first relapse, first salvage constitutes a third line of therapy (i.e., the HSCT counts as a line of therapy). Patients eligible for second salvage therapy are those who are refractory to first salvage therapy or who achieve complete remission with first salvage with subsequent ALL relapse. For these patients, second salvage constitutes a third line of therapy (or fourth line if HSCT has been performed). Page 11

12 Marqibo (vincristine sulfate liposomes injection) required line of therapy (e.g., third, fourth, fifth) increases with repeated relapses and/or refractoriness to multiple prior lines of therapy. With current multi-agent chemotherapy regimens, up to 90% of newly diagnosed adult ALL patients will achieve an initial CR+CRi, however only 28% to 39% achieve long-term disease control (Gokbuget and Hoelzer 2002). Response rates and outcomes are worse in middleaged adults (ages 40-59) compared to younger adults (ages 39 and younger) and are particularly poor in adults age 60 years or greater (Dores et al 2012). Relapse, which commonly follows initial remission, is associated with poor prognosis; survival probability and duration decreases following each subsequent relapse. Patients in their second ALL relapse or ALL first relapse that is refractory to a line of therapy have a median expected survival of no more than 3 months (O Brien et al 2008). For patients in third or fourth relapse or in a second relapse that is refractory to therapy, survival is expected to be weeks. There is a significant unmet medical need for an easily administered, new therapy that delivers improved efficacy with a predictable and manageable safety profile in advanced, relapsed and/or refractory Ph- adult ALL. Overview of Vincristine Vincristine has been used for over 40 years as an important component of multi-agent ALL induction, consolidation, and maintenance phases of treatment. Vincristine s efficacy and safety profiles are well characterized. Vincristine binds to tubulin, a microtubular protein of the mitotic spindle, causing cellular metaphase arrest (Gidding et al 1999). Vincristine has a very narrow therapeutic index, with little separation between the therapeutic and toxic doses. Despite an approved adult dosage of 1.4 mg/m 2, the oncology community and most vincristine-containing cancer treatment regimens routinely limit individual standard vincristine doses to 2.0 mg (i.e., dose capping) in an attempt to minimize neurotoxicity. Dose capping regardless of patient size combined with rapid plasma clearance limit vincristine delivery to target tissues and efficacy optimization. With increasing cumulative dose and dose-density, toxicity mounts and may lead to vincristine dose delays, dose reductions, or complete discontinuation. The 2.0 mg dose cap has also limited the study and usage of vincristine as a monotherapy. Whether administered as a bolus or continuous infusion, and regardless of dosing schedule, unacceptable toxicity has prohibited meaningful standard vincristine dose escalation. If more vincristine could be safely delivered to cancer cells, efficacy may be meaningfully enhanced. Page 12

13 Marqibo (vincristine sulfate liposomes injection) Marqibo : Nonclinical Findings and Clinical Pharmacology Talon designed Marqibo to target the delivery of a larger total dose of vincristine to tumor cells by encapsulating vincristine within the aqueous core of unique, nanoparticle, sphingomyelin and cholesterol liposomes. In animal studies, administration of Marqibo produced markedly increased plasma total (encapsulated plus free) vincristine levels compared to standard vincristine because of decreased clearance, resulting in prolonged plasma circulation time. Additional animal studies found that Marqibo delivers larger amounts of vincristine, for an extended period of time, to tissues that are most commonly affected by ALL (i.e., bone marrow, lymph nodes, and spleen) and observed a greater tumor response with Marqibo when administered at the same dose as standard vincristine. The anti-tumor effect of Marqibo was dose-dependent and larger doses of Marqibo could be infused and tolerated than of standard vincristine. The animal toxicological profile of Marqibo was similar to that observed with vincristine, with no new or unexpected toxicity. In clinical pharmacology studies, the total amount of vincristine (encapsulated plus free) delivered by Marqibo has a longer elimination half-life and significantly larger area under the curve (AUC) compared to standard vincristine. With Marqibo, vincristine is retained in the circulation in an encapsulated form and concentrations of released vincristine in plasma are undetectable at most time points, findings that are consistent with reduced immediate bioavailability. Given the nonclinical findings and supportive Marqibo clinical pharmacology observations, Talon designed the Marqibo clinical development program to enable increased total vincristine doses beyond the level that has generally been possible with standard vincristine, and to assess the impact of the increased dosing and likely increased exposure to cancer cells. An increase in the vincristine therapeutic index, which results from an increase in efficacy without a corresponding increase in toxicity, could lead to a new Ph- ALL treatment paradigm. Marqibo : Clinical Efficacy Given the dose response observed in nonclinical studies and findings from a Phase 1/2 dose escalation study (VSLI-06) in adults with relapsed or refractory ALL that weekly Marqibo 2.25 mg/m 2 was the maximum tolerated dose (MTD) and associated with encouraging anti- ALL activity, Talon designed the pivotal Phase 2 Study HBS407 to evaluate the efficacy of Page 13

14 Marqibo (vincristine sulfate liposomes injection) Marqibo monotherapy at 2.25 mg/m 2 with no dose cap. Marqibo monotherapy was selected in order to isolate any beneficial treatment response specific to Marqibo, because the target population had already received and progressed following multi-agent therapies, and to minimize exacerbation of severe and protracted cytopenias. HBS407 was conducted using a Simon s 2-stage minimax design. Assuming a null hypothesis that the CR+CRi rate is 10% versus an alternative hypothesis that the true CR+CRi rate is 20%, fewer than 3 CR+CRi in a first stage of 29 evaluable subjects would lead to study termination. If there were 3 or more CR+CRi, additional subjects would be accrued until 9 CR+CRi or up to 56 total (first plus second stage) evaluable subjects. Achievement of 9 CR+CRi in 56 subjects (16 %, [95% CI 7.6, 28.4]) was the pre-defined threshold for a positive study and excluded a 7.5% or lower CR+CRi rate. For this design, the alpha was set at 0.10 and the power was 80%. The study protocol was later amended to increase the sample size from 56 to 65 in order to accommodate the collection of pharmacokinetic data. The protocol specified primary analysis of CR+CRi rate was based on principal investigator (PI) assessment of response data in the intent-to-treat (ITT) population of 65 Marqibo treated subjects. An ALL expert committee (Independent Response Review Committee, IRRC), blinded to all PI response assessments was used to corroborate PI assessments when possible. HBS407 enrolled 65 heavily pretreated adults (age range 19 to 83 years; ECOG performance status range: 0 to 3) with advanced, relapsed and/or refractory Ph- ALL requiring third, fourth, fifth or greater line of therapy. The HBS407 study population represents the most advanced and unfavorable adult ALL population studied to date. The following subject characteristics reflect the advanced nature of their underlying ALL and challenges to continued treatment: 100% had prior exposure to standard vincristine; 51% had already received 3 or more lines of anti-leukemia therapy; Subjects had received a median of 10 (range 4 to 15) different prior drugs with near universal prior exposure to steroids, anthracyclines, cyclophosphamide, and cytarabine; 48% had relapsed following one or two prior transplants; 45% were refractory to their immediate prior line of therapy; Page 14

15 Marqibo (vincristine sulfate liposomes injection) 62% were CD34+ on immunophenotype analysis, which is reported to adversely affect outcome (Czuczman et al 1999); 59% of cytogenetic profiles were unfavorable and none were favorable; and, 80% had residual vincristine associated neuropathy (72% peripheral neuropathy) at study entry. Individual doses (median 4.12 mg [range 3.14 to 5.51 mg]), cumulative doses (median mg [range 3.5 to mg]), and dose densities (median 2.25 mg/m 2 /week [range 0.94 to 2.29 mg/m 2 /week]) of Marqibo significantly exceeded those reported for standard vincristine dosing. In HBS407, 72% of doses were administered in the out-patient setting. This is in contrast to other ALL treatment options that might require an in-patient administration to support consecutive day dosing and more intensive supportive care measures. In the primary ITT analysis using response data assessed by PIs, 20% (13/65, [95% CI 11.1, 31.8]) achieved CR+CRi. Of note, in the original target population of 56 subjects, 11 (20%) achieved CR+CRi. The IRRC corroborated clinical responses in 11 of the 13 cases of CR+CRi. The other 2 subjects were assessed by the IRRC as having bone marrow blast (BMB) responses, which represent morphological CR without recovery of both the neutrophil and platelet counts (called CR* in studies of nelarabine in T-cell ALL). The CR+CRi rate when using IRRC assessment was 16.9% (11/65, [95% CI 8.7, 28.3]). Regardless of whether using PI or IRRC assessment, the lower bound of the 95% CI is greater than 7.5%. In HBS407, Marqibo monotherapy demonstrated efficacy even in patient subsets with the poorest prognosis, including those with refractory disease and those in need of third, fourth, and fifth or greater line therapy. Complete response rates were comparable at 19%, 21%, and 22% in the 32, 24, and 9 subjects who received Marqibo as third, fourth, and fifth or greater line of therapy, respectively. Four of 29 (14%) of subjects with relapsed ALL refractory to one or more immediate prior lines of therapy achieved CR+CRi as a result of Marqibo monotherapy. Refractoriness was to single agents such as clofarabine and multi-agent treatment regimens inclusive of vinca alkaloids. In addition to Marqibo 2.25 mg/m 2 monotherapy producing clinically meaningful response rates, the duration of responses in HBS407 compared favorably as well. For the 13 subjects in Study HBS407 who achieved CR+CRi per the primary analysis and the 11 subjects in Page 15

16 Marqibo (vincristine sulfate liposomes injection) Study HBS407 who achieved CR+CRi based on IRRC assessment, the median duration of remission was 23 weeks, with a maximum duration of remission well over one year (66 weeks). This median duration of remission is more consistent with expectations for a population in first relapse in need of second-line (first salvage) therapy (Thomas et al 1999) and not one entirely (100%) composed of subjects in need of third or greater line of therapy. Additionally, 9 (69%) subjects in HBS407 who attained a CR+CRi from Marqibo had a response duration that exceeded the duration of response to their immediately prior line of ALL therapy. This pattern contrasts with the normal pattern of successive response durations being significantly shorter than the previous response. The median overall survival in the ITT population (N = 65) was 4.6 months and in those achieving CR+CRi (N = 13) was 7.7 months (range 2.4 to months). Five subjects had overall survival in excess of 1 year as a result of Marqibo monotherapy. In 12 (18.5%) subjects transplantation was performed a median of 3.1 months after beginning Marqibo monotherapy. There is no published, prospective, randomized, controlled experience in a subject population corresponding to the advanced relapse and refractory patients enrolled in HBS407 that can be used as a historical comparison. However, a retrospective study of 288 relapsed and/or refractory patients, all in need of 3 rd line ALL therapy, treated at M.D. Anderson Cancer Center (MDACC) (O Brien et al. 2008) provides a cohort with the closest approximation to the study population of HBS407. In the MDACC study, there was a population of 70 B-cell and T-cell lineage ALL patients who closely compared to the HBS407 ALL population. After excluding the 14 patients who were Ph+ or who received Marqibo as their MDACC treatment, we identified a 56 patient population that most closely compares to the HBS407 population. Key similarities include the exclusive use of monotherapy and the fact that greater than 50% of subjects in both groups had 3 or 4 recognized adverse prognostic factors such as duration of first CR of less than 36 months, and platelet count less than 50 x 10 9 /L, serum albumin less than 3 g/l, and percentage of bone marrow blasts greater than 50% at the time of relapse (O Brien et al 2008). Key differences include the fact that 55 of the 70 (79%) MDACC single-agent treated group were in a first relapse in contrast to the 58% of HBS407 subjects who were in second or greater relapse. All of the MDACC group was evaluated in the context of third-line therapy, while HBS407 evaluated Marqibo as third, fourth, or fifth or greater line of therapy. These differences, combined with more ALL pretreatment in HBS407 subjects and a higher proportion of subjects who had previously received and progressed following transplantation in HBS407, makes the comparison conservative. The Page 16

17 Marqibo (vincristine sulfate liposomes injection) HBS407 population would be predicted to have poorer outcome than the MDACC cohort. Key outcomes comparisons include: The complete response rate in Study HBS407 as a result of weekly, single-agent Marqibo 2.25 mg/m 2 (20.0%) was ~ 4.7-fold greater than was observed in the MDACC single-agent group (4.3%). The early plus induction (30-day) mortality rate with single-agent Marqibo 2.25 mg/m 2 (12.3%) was about half that for single-agent, non-marqibo (30.4%) used at MDACC. Median overall survival was longer with Marqibo monotherapy in HBS407 (4.6 months) than was observed with single- and multi-agent therapy at MDACC (2.1 and 3.3 months, respectively). Thus, based upon a conservative comparison with published literature (O Brien et al 2008), Marqibo provides greater clinical benefit than the expected experience with a single agent and has the potential to advance the care of patients with Ph- Adult ALL. The increased response rate and duration of response in HBS407 compared with the MDACC historical cohort occurred in the context of a median cumulative vincristine exposure from Marqibo that was 2-fold greater (range: 1.57-fold to 2.76-fold) than would have been achieved with standard vincristine dosing based on the range of subject body surface areas in HBS407. The median individual Marqibo dose (in mg of vincristine) was 4.12 mg (range 3.14 to 5.51 mg), median dose density was 2.25 mg/m 2 /week (range 0.94 to 2.29 mg/m 2 /week), and median cumulative dose of Marqibo delivered in HBS407 was mg (range 3.5 to mg). Based on their body surface area, all subjects in this study would have received 2 mg (capped) individual doses if treated with standard vincristine. Supportive evidence of efficacy was observed in Study VSLI-06, a Phase 1/2 dose-escalation study conducted in a heterogeneous population of relapsed and/or refractory (advanced) ALL subjects (one Ph+ subject, two Burkitt s lymphoma/leukemia subtypes, subjects with primary refractory ALL, and subjects in need of first salvage [38.9%]). Marqibo (1.5 to 2.4 mg/m 2 ) was combined with pulse dexamethasone 40 mg. In this group of subjects who also had universal prior vincristine exposure, Marqibo 2.25 mg/m 2 once weekly induced 3 CRs and 1 PR for an overall response rate of 22.2%. Page 17

18 Marqibo (vincristine sulfate liposomes injection) In summary, Marqibo monotherapy provides evidence of meaningful efficacy as measured by CR + CRi, durable response, and overall survival in patients with this advanced disease compared to the expected response. Clinical evidence of unexpected and significant response to 2.25 mg/m 2 in HBS-407 supports accelerated approval. Page 18

19 Marqibo (vincristine sulfate liposomes injection) Marqibo : Safety Results The safety experience with Marqibo was similar to that expected for an advanced, relapsed and/or refractory adult ALL patient population and one receiving standard vincristine. No new or unexpected toxicities were observed with Marqibo administration either in nonclinical studies or in clinical experience to date. There is no clinical evidence that the increased vincristine exposure provided by Marqibo resulted in any increase in vincristinerelated adverse events (AEs). Across the development program, Marqibo has been administered to 774 subjects, including 83 adults with advanced, relapsed and/or refractory ALL exposed to the proposed marketing dose of 2.25 mg/m 2. Across the HBS407 and VSLI-06 studies in advanced ALL patients (N = 101), 19.8% of subjects died during the treatment period and 46.5% died during the follow-up period, an experience that is consistent with the expected mortality in this patient population. The most common AEs occurring with the proposed dose level of 2.25 mg/m 2 in adults with advanced, relapsed and/or refractory ALL (Target Indicated Dose Group) were constipation (56.6%), nausea (51.8%), pyrexia (42.2%), fatigue (34.9%), peripheral neuropathy (37.3%), decreased appetite (36.1%), febrile neutropenia (36.1%), diarrhea (34.9%), and anemia (30.1%). The majority of instances of peripheral neuropathy were of Grade 1 or 2 in severity. Among the 31 subjects (37.3%) treated with Marqibo 2.25 mg/m 2 who reported new or worsening neuropathy during the study period, 21 (67.7%) had Grade 1 or 2 severity peripheral neuropathy and 10 (32.3%) had peripheral neuropathy of Grade 3 severity. This pattern extended to most of the neuropathy-associated AE terms. This pattern is particularly meaningful because of universal prior vincristine exposure resulting in evidence of residual (mostly Grade 1) neuropathy in 80% of subjects at baseline just prior to the initiation of Marqibo. The protocols for Studies HBS407 and VSLI-06 each specified dose modification in the event of Grade 3 or persistent Grade 2 nonhematological toxicity. The observation that the majority of neuropathy-associated AEs had their final assessment as severity grades of Grade 1 or 2 is a measure of the success of the employed dose modification strategy. This successful limitation of the amount of Grade 3 or greater toxicity combined with the achievement of CR+CRi in 7 of 15 (47%) subjects in HBS407 who required a dose reduction suggest that the developed dose modification algorithm is effective. Page 19

20 Marqibo (vincristine sulfate liposomes injection) Marqibo : Benefit vs. Risk The findings from Studies HBS407 and VSLI-06 are reasonably likely to predict clinical benefit for adult Ph- ALL in the setting of second or greater relapse or disease that has progressed following two or more lines of anti-leukemia therapy. Marqibo monotherapy was able to induce CR+CRi in subjects having prior standard vincristine exposure and ALL progression without causing increased toxicity. This response was achieved among high mortality patients who had not had previous clinical benefit from treatment and represent 6 particularly challenging clinical scenarios as summarized below (O Brien et al 2008): Relapse following intensive chemotherapy and allogeneic hematopoietic stem cell transplantation; Relapse and refractoriness to an immediately prior line of salvage therapy; Relapse and/or refractoriness in the setting of residual toxicity from prior therapy; Fourth and fifth line of therapy; Third relapse setting; and, Relapse and/or refractoriness in the setting of defined predictors of especially poor prognosis (e.g., initial CR duration < 36 months, platelet count at relapse < /L, and bone marrow blast percent of > 50%). Confirmatory Study and Special Protocol Agreement To confirm the clinical benefit of Marqibo for the treatment of Ph- ALL, Talon has initiated a randomized, controlled study, under a Special Protocol Assessment (SPA) agreement, in the elderly ( 60 years) Ph- ALL setting of first line, multi-agent treatment, with Marqibo replacing standard vincristine. The primary objective of the study is to compare overall survival (OS) with Marqibo versus standard vincristine injection as a component of multiagent induction, intensification, and maintenance chemotherapy. It is hypothesized that Marqibo will favorably impact overall survival by improving induction rates, eliminating minimal residual disease, extending remission duration, and reducing induction-related mortality. The study was initiated in fourth quarter 2011 and should complete enrollment in approximately 4 years. The key elements of the study design are as follows. Phase 3, international, multicenter (up to 100 sites), open-label, controlled trial of subjects 60 years who have newly diagnosed, histologically proven, untreated Ph- Page 20

21 Marqibo (vincristine sulfate liposomes injection) ALL, with 5% bone marrow blasts. Eligible subjects are randomized in a 1:1 ratio to either standard vincristine or Marqibo (each in combination with cyclophosphamide, corticosteroids, L- asparaginase, cytarabine, 6-mercaptopurine, methotrexate, and 6-thioguanine, for up to 24 months), using a permuted-block algorithm within each site and stratification group. Standard vincristine is dosed at 1.4 mg/m 2, with a 2 mg individual dose cap, and infused IV over 10 minutes. Marqibo is dosed at 2.25 mg/m 2 (without any dose cap) and infused IV over 60 minutes. Recruitment is planned to stop when a minimum of 332 events (deaths) have been observed to ensure power to assess the primary endpoint. It is estimated that 348 to 400 subjects will be randomized to treatment over a 35 to 40 month period (rate of 10 subjects per month). Follow-up is expected to be up to 25 months after the last subject is enrolled. Conclusions The Marqibo data combined with the post-approval commitment meet all the ODAC criteria for accelerated approval based on single-arm trials (Food and Drug Administration 2011). Specifically: Patients with second or greater relapsed and refractory ALL have low survival, with median survival below 3 months. This falls within the ODAC recommendation to focus on cancers with high unmet need. Second or greater relapsed and refractory ALL is a very small population, with about 500 patients per year. This aligns precisely with the references by ODAC members to reserve accelerated approval recommendations for small orphan populations with high mortality. Thus, there is a clear unmet need to support accelerated approval. Marqibo data are reasonably likely to predict benefit over available therapy. The results demonstrated in Study HBS407 are unprecedented, demonstrating a 20% complete response rate, which is especially relevant for this terminal population with little hope from current therapies and only 1 representative comparative trial from MDACC. This agrees with both the ODAC recommendation and the established definition for accelerated approval candidates to be reasonably likely to predict a clinical benefit over available therapy. Page 21

22 Marqibo (vincristine sulfate liposomes injection) The ODAC, on February 8, 2011, supported FDA s recommendation that Sponsors should have an agreed upon clinical design for post-approval confirmation prior to the Agency granting an accelerated approval. Talon has initiated a confirmatory trial for Marqibo based on a design discussed with the Agency and for which there is SPA agreement. In addition, Talon has completed plans for dosing identification in pediatric and adolescent subjects, as well as studies with Marqibo in other indications, which will further characterize the benefits of Marqibo. Talon has proactively aligned with all guidance provided by the ODAC and believes that all the established standards for gaining accelerated approval have been fulfilled for Marqibo in advanced, relapsed and/or refractory adult Ph- ALL. Page 22

23 Marqibo (vincristine sulfate liposomes injection) 1. Introduction Overall, there are about 2000 new cases of acute lymphoblastic leukemia (ALL) diagnosed in US adults each year. In the approximate 1400 adults with Philadelphia chromosome-negative (Ph-) ALL, about 60% will fail to respond or relapse following treatment. Thus, there is significant clinical need for new and improved therapies for adults with Ph- ALL, both for front-line treatment and in relapse. Effective treatment may also enhance the likelihood of bone marrow transplant. Vincristine is a standard component of most phases of chemotherapy in Ph- adult ALL (Larson et al 1995). However, vincristine s potentially potent (Leonetti et al 2004) efficacy is limited by its narrow therapeutic index due primarily to dose-limiting neurotoxicity. Higher doses of standard vincristine are associated with increased efficacy, but at the expense of significant and potentially debilitating toxicity. Continuous intravenous (IV) infusion neither improves efficacy nor ameliorates toxicity (Jackson et al 1985a, 1985b). Because of the narrow therapeutic index with vincristine, dose capping at 2 mg is standard practice despite approval at 1.4 mg/m 2. Vincristine sulfate liposomes injection (VSLI; Marqibo, hereafter referred to as Marqibo ) is a novel formulation that encapsulates vincristine in proprietary liposome nano-particles called Optisomes. Optisomes are made from sphingomyelin (SM) and cholesterol (Chol), which are normal components of human plasma membranes. Optisomes are uniquely suited to contain, deliver, and dose-intensify vincristine. Marqibo has longer plasma circulation time than vincristine, targets encapsulated drug preferentially to tumors, and delivers vincristine to tumor cells in a continuous and prolonged manner, maximizing its cell cycle dependent activity on malignant cells. If more vincristine is delivered to malignant cells without a corresponding increase in toxicity, then Marqibo could improve ALL treatment in front-line treatment or even relapse. Currently, there are no approved or standard-of-care options for patients with Ph- ALL in second or greater relapse or whose disease has progressed following two or more lines of anti-leukemia therapy. Given the potential effectiveness of increasing vincristine exposure to tumor cells, Marqibo is being developed, under the Food and Drug Administration (FDA) Fast Track Designation program and has received Orphan drug designation from the FDA for the treatment of Ph- ALL in adults in second or greater relapse or whose disease has progressed following two or greater treatment lines of antileukemic therapy. The European Medicines Agency (EMA) has also granted Orphan drug designation to Marqibo for the treatment of acute lymphoblastic leukemia. Page 23

24 Marqibo (vincristine sulfate liposomes injection) On February 8, 2011 the ODAC conducted a meeting during which panelists discussed circumstances in which single-arm trials would be appropriate for accelerated drug approval (Food and Drug Administration 2011), including: (1) very small, orphan population; 2) evidence of significant efficacy and favorable benefit-risk; and 3) initiation of a postapproval study to confirm clinical benefit. This Briefing Document reviews the Marqibo development program and then presents the findings from Study HBS407, which affirms a substantial clinically meaningful effect on clinical response in relapsed or refractory ALL. HBS407 is a single arm phase 2 study of Marqibo in this patient population. In addition, Study VSLI-06, which was designed as a maximum tolerated dose (MTD) study, provides supporting evidence of efficacy. The design and findings from the studies are reviewed in detail along with the safety experience across the 774 patients that have received Marqibo in clinical development, of which 109 have been exposed at the 2.25 mg/m 2 dose proposed for marketing. Finally, TTX404 is a confirmatory study being conducted under Special Protocol Agreement (SPA) with FDA that is currently enrolling patients. The design of this study is discussed in Section 7. Thus, Talon believes the experience with Marqibo satisfies the conditions discussed by the ODAC on February 8, 2011 for accelerated approval. Page 24

25 Marqibo (vincristine sulfate liposomes injection) 2. Relapsed and Refractory ALL: Current Treatment Options and Outcomes 2.1 Overview of ALL Leukemia is the second most prevalent hematologic neoplasm, which includes lymphomas and myeloma (Altekruse et al 2010). Leukemias are broadly classified according to acuity (acute vs. chronic) and cell line of origin (lymphoid vs. myeloid). Acute leukemias are primarily disorders of pronounced maturation arrest, while chronic leukemias are primarily disorders of uncontrolled malignant precursor cell proliferation. Of the 43,050 new cases of leukemia diagnosed in the United States (U.S.) in 2010, there were approximately 5,300 cases of ALL, which is defined as an orphan disease under the US Rare Drug Act of The incidence of ALL has strong age dependence, with a peak incidence at 3 to 6 years of age. ALL is uncommon in young adults, and then becomes increasingly common with advancing age. The biphasic age incidence strongly suggests that there are significant biological differences between ALL in children and adults. One important distinction is response to therapy: While 85 to 90% of children with ALL will have favorable outcomes with current therapies, accompanied by long-term survival benefit, outcomes remain quite poor for adults (Gokbuget and Hoelzer 2002). Adult (age 18 years) ALL is one of the rarest hematologic malignancies, with only approximately 2,000 new cases diagnosed annually in the U.S. Of these, approximately 1,400 are Ph- Adult ALL (1,100 cases B-lineage and 300 cases T-lineage). Figure 1 illustrates the natural progression of Ph- adult ALL and the anticipated number of available patients at each stage of disease. Based on published treatment response rates and treatment-related mortality rates, each year in the U.S. approximately 840 patients relapse from remission or are refractory to front-line therapy and are in need of second-line therapy, and 55% of these (458 patients) will relapse a second time or be refractory to second-line therapy, with worsening prognosis, decreased survival, and need for a third line of therapy (Tavernier et al 2007, Thomas et al 1999, O Brien et al 2008). The required line of therapy (e.g., third, fourth, fifth) increases with repeated relapses and/or refractoriness to multiple prior lines of therapy. Patients with second or greater relapsed and refractory ALL have low survival, with median survival below 3 months. Page 25

26 Marqibo (vincristine sulfate liposomes injection) Figure 1. Stages of Ph- Adult ALL and Available Patients in the U.S. Source: Tavernier et al 2007, Thomas et al Front-Line (First-Line) Treatment of Ph- Adult ALL The primary goal of therapy in the front-line setting is complete and durable remission that is accompanied by elimination of the leukemic clone. Secondary goals include restoration of normal hematopoiesis and restoration of normal performance status. Success in achieving a complete remission and durable response is inversely related to age (Gokbuget and Hoelzer 2002). Complete remission (CR) rates (i.e., absence of overt evidence of leukemia in peripheral blood and bone marrow as well as absence of measurable extramedullary disease) in the front-line setting are reported as 90%, 81%, and 57% for ages < 30 years, years, and 60+ years, respectively, while 3-year disease-free survival rates are 47%, 38%, and 12% respectively. Table 1 lists risk factors for adverse outcomes based on a combination of clinical, morphologic, cytogenetic, and immunophenotypic presentation (Itakura and Coutre 2008, Hoelzer et al 1988). Page 26

27 Marqibo (vincristine sulfate liposomes injection) Table 1. Prognostic Predictors for Relapse Following Front-Line Therapy Age 30 years White blood cell (WBC) count 30,000 (10 6 /ml) Immunophenotype of mature B-cell or early T-cell Karyotypes of t(4;11), t(1;19), hypodiploid, 7, +8 Persistent minimal residual disease (MRD) following induction Failure to achieve first CR by week 4 of initial induction therapy Figure 2 depicts one of the standard and widely accepted front-line Ph- adult ALL treatment regimens (Larson et al 1995). Treatment regimens for adult ALL are divided into multiple phases, including induction, one or more consolidation (also called intensification) phases, and maintenance phases. Vincristine can be used as a component of each of these phases of treatment. Adult ALL treatment regimens have evolved over time to closely resemble the intensity and structure of childhood ALL treatment regimens. Gradual intensification over many years by the incorporation of additional active drugs has improved remission durations in select patients (Durrant et al 1997, Fiere et al 1993, Hoelzer et al 1993, Larson et al 1995, Mandelli et al 1996, Kantarjian et al 2000). Figure 2. Cancer and Leukemia Group B (CALGB) Protocol 8811 Schematic Source: Larson et al Page 27

28 Marqibo (vincristine sulfate liposomes injection) 2.2 Reported Outcomes in Relapsed and Refractory ALL For adult patients with Ph- ALL who relapse after achieving a CR or undergoing hematopoietic stem cell transplantation (HSCT), or who fail to enter first remission following multiple therapeutic attempts, 5-year survival is 7% (Tavernier et al 2007, Fielding et al 2007). In relapsed cases, leukemia is frequently highly resistant to conventional therapies, and there are no consensus treatment guidelines or standardized approaches to therapy First Relapse Therapy Experience Adult patients with Ph- ALL that is refractory to front-line induction therapy or who achieve an initial remission but subsequently relapse during or following consolidation or maintenance therapy are eligible for second-line therapy (Figure 3). Given the low survival for relapsed Ph- Adult ALL, HSCT has been extensively employed as post-remission therapy in the front-line setting for eligible patients. If HSCT has been performed in first remission and prior to the first relapse, first relapse therapy would actually constitute a third line of therapy (i.e., the HSCT counts as a line of therapy). The major goal of first relapse treatment is to achieve remission of sufficient duration to facilitate allogeneic HSCT. Page 28

29 Marqibo (vincristine sulfate liposomes injection) Figure 3. First Relapse and Refractory Therapy Scenarios HSCT = hematopoietic stem cell transplantation Source: Thomas et al., First relapse therapy may consist of a patient s original front-line induction regimen with or without additional drugs, high- or intermediate-dose cytarabine-based regimens, methotrexate combined with asparaginase, or a single-agent treatment. There have been many approaches to first relapse therapy, but none have emerged as definitive therapy. Because of the toxicity of multi-agent second-line therapy, especially in heavily pre-treated patients, single-agent therapy is often the only tolerable option. In a single-center (M.D. Anderson Cancer Center [MDACC]) experience, 33% of patients responded to multi-agent, second-line therapy and 8% of patients responded to single-agent, second-line therapy (Thomas et al 1999) Second Relpase and Refractory Therapy Experience Adult patients with Ph- ALL that is refractory to first relapse therapy or who achieve a CR with first relapse therapy with subsequent ALL relapse are eligible for second relapse (third or greater line therapy) (Figure 4). The goals of third-line therapy for a second relapse include achievement of a CR, or disease control, with extended survival and/or survival of sufficient duration to allow for a potentially curative HSCT. Treatment is challenging in these Page 29

30 Marqibo (vincristine sulfate liposomes injection) patients due to the residual and ongoing toxic effects of prior therapy, highly therapy-resistant leukemia, and in some cases fulminant disease. O Brien and colleagues reported retrospective data on 288 adults with ALL who received third-line therapy at MDACC after disease recurrence on MDACC front-line regimens or after referral for recurrent ALL (O Brien et al 2008). Of these, 22.9% of patients who received multiple anti-leukemia agents responded to third-line therapy. The subgroup of Phadult ALL patients treated with non-marqibo single-agent, third-line therapy had a response rate of 3.6% (2/56). Section 5.6 reviews the O Brien study in more detail to provide a source of historical comparison for the Marqibo experience in HBS407 and VSLI-06 since there are no published data on fourth-line or greater therapy. Figure 4. Second Relpase and Refractory Therapy Scenarios Source: O Brien et al Page 30

31 Marqibo (vincristine sulfate liposomes injection) 3. Overview of Vincristine Vincristine, a vinca alkaloid (Noble 1990), has cell cycle-specific activity against a wide number of neoplasms including ALL, non-hodgkin s lymphomas, Hodgkin s disease, myeloma, Wilms tumor, neuroblastoma, breast cancer, urothelial carcinoma, soft tissue sarcomas, and small cell and non-small cell lung cancers (Gidding et al 1999). The primary mechanism of action of vincristine is tubulin binding, which interferes with spindle formation during mitosis, leading to cellular metaphase arrest. The FDA approved vincristine in 1963 at a dose of 1.4 mg/m 2. Vincristine remains a near universal component of remission induction, intensification (remission consolidation), remission maintenance, and salvage therapies for ALL. Substantial clinical evidence also shows that the efficacy and toxicity of vincristine are directly related to dose. The activity of vincristine is enhanced with prolonged exposure of tumor cells (Gidding et al 1999), presumably increasing the exposure to the target cells undergoing mitosis, the sensitive part of the cell cycle. Nonclinical studies have found that the concentration and extent of overall exposure both influence vincristine s anti-leukemia activity (Jackson and Bender 1979). In humans, standard vincristine anti-leukemia activity is limited by a very narrow therapeutic index and dose capping to 2 mg (less than 1 mg/m 2 in the average 70 kg man). Some patients have had dramatic and unexpected tumor responses in cases of accidental vincristine overdose, suggesting improved response with higher dosing. Early attempts at vincristine dose intensification (above the approved dose of 1.4 mg/m 2 ) were associated with increased anti-cancer activity but accompanied by severe neuropathic adverse events (AEs), the most common dose-limiting toxicity (Carbone et al 1963, DeVita et al 1970, Carde et al 1983, Epelbaum et al 1990, Longo et al 1986). Dose-limiting toxicity symptoms and signs emerge rapidly at individual doses > 2 mg and at cumulative doses as modest as 6 to 8 mg (Carbone et al 1963). Of 23 major studies of front-line adult ALL published between 1993 and 2005, 16 employed either a fixed 2.0 mg standard vincristine dose or applied a 2.0 mg per dose cap (Source: Appendix A of SCE). In clinical practice, the oncology community limits standard vincristine doses to 2.0 mg to limit neurotoxicity. Based on a dose of 1.4 mg/m 2, a 2 mg dose cap reflects significant under dosing for the large population of adults whose body surface area (BSA) exceeds 1.43 m 2. Metabolism of vincristine in humans has been extensively studied. The formation of multiple metabolic products has been reported, and studies in humans (Bender et al 1977, Jackson et al 1978) and animals (Castle and Mead 1978; Houghton et al 1983, 1984) suggest that Page 31

32 Marqibo (vincristine sulfate liposomes injection) metabolism and/or biodegradation of vincristine yields multiple (up to 6 to 11) peaks. However, only a few of these peaks have been identified by high performance liquid chromatography (HPLC) analysis of biological fluids after in vivo injection or in vitro incubation of vincristine: 4-deacetyl vincristine and its isomer, N-desformylvincristine, 4- deacetyl-e-desoxy vincristine, and a vincristine isomer (Houghton et al 1983, Sethi et al 1981a, Sethi et al 1986). The structures and identities of many of the metabolites or degradation products and the pathways through which they are formed remain largely unknown (Rosazza et al 1992). In vitro and in vivo studies suggest involvement of cytochrome P450 (CYP) 3A4 CYP2D6,CYP2C10, and CYP2C19. Additional in vitro studies have suggested that individuals with higher levels of CYP3A5 protein are capable of metabolizing vincristine at a higher rate and to a greater extent than those with low levels of CYP3A5 (Dennison et al 2007, 2008). 3.1 Vincristine-Induced Neuropathy Neuropathy is a common AE experienced by patients. Prior and ongoing neuropathies are also predisposing risk factors for the subsequent development of chemotherapy-induced neuropathy. The majority of subjects (60-80%) in Studies HBS407 and VSLI-06 reported prior or ongoing medical conditions consistent with vincristine-induced neuropathy at the time of entry into the Marqibo studies (Section 6.6.1). Baseline neuropathy was expected in this patient population, since all subjects had prior exposure to standard vincristine. These rates of baseline neuropathy seen in the Marqibo studies are comparable to those reported following standard vincristine at its labeled dose, as evidenced by published findings from two research groups (Haim et al 1994, Verstappen et al 2005). In the Haim study (1994), 104 patients with non-hodgkin s lymphoma were treated with multi-agent therapy including standard vincristine dosed at 1.4 mg/m 2, which was administered no more frequently than every 2 weeks. The overall incidence of neuropathy was reported as 92%. In the Verstappen study (2005), patients with non-hodgkin s lymphoma or Hodgkin s disease were treated with multi-agent therapy including standard vincristine at a dose of 4 mg every 3 weeks (dose density of 1.33 mg/week) or 2 mg every 3 weeks (dose density of 0.67 mg/week). Paresthesias, numbness, and muscle/bone pain were reported by 60%, 70%, and 62% of patients, respectively. Page 32

33 Marqibo (vincristine sulfate liposomes injection) 4. Composition, Nonclinical Overview, and Clinical Pharmacology of Marqibo 4.1 Composition of Marqibo Despite high activity against ALL in vitro, the anti-leukemia activity of standard vincristine is limited by a narrow therapeutic index and subsequent dose capping to 2 mg. Vincristine encapsulated in liposome may allow for higher doses, increasing the likelihood of cancer response, thereby optimizing its use. The potential for liposome use as a drug-delivery system was first described in 1968 (Sessa and Weissman 1968). Drugs encapsulated in a liposome drug-delivery system offer the following advantages (Drummond et al 2008): Clearance of the active drug in the blood is reduced, since the encapsulated active drug is protected from extensive distribution and elimination (acting as a sustained-release formulation). This allows the active drug to have a more prolonged duration of action at a consistent lower level of exposure (higher therapeutic efficacy). For anti-cancer drugs that are cell cycle dependent or have effects that are transient, the sustained-release characteristics of liposomal drugs in target tissues can improve antitumor activity. The side-effect profile of the liposomal formulation is different; however, in general it is felt to cause fewer adverse effects compared to unencapsulated drug in the blood. Due to the permeable microvasculature uniquely associated with tumors (i.e., fenestrated capillaries), and to a lesser extent some normal tissues/organs such as bone marrow, lymph nodes, and the spleen, liposomes can readily and preferentially accumulate in tumor tissue, leading to higher localized drug concentrations. This is in contrast to the normal, continuous capillaries found in many normal tissues that inhibit extravasation of liposomes into those tissues. Non-clinical experiments with SM-based liposomal formulations of vincristine demonstrated the ability to enhance anti-cancer activity without exacerbation of toxicity (i.e., widen the therapeutic index), enhance vincristine penetration and concentration in tumors, and prolong circulation time. These findings lead to development of Marqibo as a liposomal nanoparticles formulation of vincristine called Optisomes. Optisomes, the liposomal carrier component of Marqibo, are made from SM and Chol, which are normal components of human plasma membranes. The proprietary liposomes consist of SM and Chol in a 58:42 ratio (mol:mol), with a nominal mean diameter of 115 nm. Page 33

34 Marqibo (vincristine sulfate liposomes injection) The preferential vincristine delivery to, slow release, and accumulation in tumor tissues may result from extravasation of the liposomes through pores present in neovasculature of both solid and hematological malignancies (Carmeliet and Jain 2000, Yuan et al 1995, Yuan et al 1994, Moehler et al 2001, Salven 2001, Orpana and Salven 2002). In contrast to tumor vasculature, capillaries in most normal tissues and organs have continuous endothelial linings, and liposome extravasation would therefore not be expected to occur to the same extent. Normal organs that are exceptions to this include the liver, spleen, bone marrow, and lymph nodes, where the capillaries are fenestrated or discontinuous. Liposomes also have the potential to improve the safety profile of anticancer agents and thus may allow the use of higher dose levels of the drug without compromising patient safety (Rahman et al 1982, Berry et al 1996, Valero et al 1995, Muggia et al 1997, Lister 1996, and White et al 1998). 4.2 Nonclinical Overview In preclinical studies, Marqibo had significantly longer circulation half-life, increased plasma AUC of total vincristine, and much smaller volume of distribution at steady state (V ss ) than did the same dose level of vincristine, consistent with encapsulation of vincristine in the long-circulating, slow-release SM/Chol liposomes. The distribution of total vincristine to tissues was slower following administration of Marqibo than standard vincristine and higher levels were detected in tumor tissue and several other organs in Sprague-Dawley Rats (Figure 5) mononuclear phagocyte system (MPS) (i.e., spleen, liver, lymph nodes, bone marrow), the reproductive organs (ovaries and epididymes), trachea, and sciatic and tibial nerves. Total vincristine levels in the brain, spinal cord, muscle and thymus were comparable to or lower than that observed for standard vincristine. Page 34

35 Marqibo (vincristine sulfate liposomes injection) Figure 5. Concentration of Vincristine in Tissues Following Standard Vincristine vs. Marqibo Administration Vincristine is primarily removed from the plasma compartment following Marqibo administration as liposomal encapsulated drug. Once present in the tissues these liposomes continue to release encapsulated drug. As a result, the high maximum concentration (C max ) and AUC values for total vincristine in tissue after Marqibo administration are not predictive of effects as similar levels of vincristine would be (due to tissue distribution/release of Marqibo ). This was supported by the observation that higher concentrations of total vincristine in liver and bone marrow after Marqibo administration compared to vincristine did not give rise to increased toxicity in these organs. In nonclinical toxicological studies, Marqibo toxicity was similar to that with standard vincristine and can be attributed to vincristine s ability to inhibit microtubule function. Importantly, no new or unexpected toxicities were observed with Marqibo in animals, compared to those observed with conventionally formulated vincristine. In the definitive repeat-dose toxicology study in the dog, one group of animals was treated with 0.8 mg/m 2 vincristine once every 2 weeks for a total of 12 doses to serve as a comparator to the corresponding Marqibo group. The spectrum of toxicities elicited by vincristine was identical to the toxicities elicited by Marqibo. Page 35

36 Marqibo (vincristine sulfate liposomes injection) Distribution to Tumors Tissue distribution studies demonstrated that total vincristine accumulation was greater in tumors after Marqibo administration, as compared to vincristine, suggesting the possibility that tumors may have greater drug exposure after Marqibo administration. Table 2 provides an example of one study in which Marqibo administration resulted in substantially higher vincristine accumulation in tumor-bearing mice, as compared to the same dose of standard vincristine. Table 2. Vincristine Levels in Tumor-bearing Mice* Administered Standard Vincristine vs. Marqibo Standard Vincristine Marqibo 4.5 mg/m mg/m 2 Fold Increase C max (ng-eq/g) , AUC (ng-eq hr/g) ,584 1,273 * Female mice bearing MX-1 tumors, N=3; drug levels measured by scintillation counting PCD-018R. An in vivo microdialysis study showed that levels of bioavailable vincristine were sustained and higher in the interstitial fluid of tumors after Marqibo administration compared to after vincristine administration. As shown in a tumor window model, vincristine delivery to tumors by Marqibo was the consequence of liposome extravasation into the tumor (through defects in the tumor neovasculature) and was not due to tumor uptake of free drug that was released from the liposomes into the circulation. In normal tissue, the Marqibo liposomes were constrained within the capillaries, with little or no accumulation in the interstitial space. Marqibo was significantly more effective than standard, unencapsulated vincristine at reducing P388 and A431 tumor progression. Antitumor Activity Marqibo s pharmacokinetic properties translated into dose-dependent anti-tumor activities; by way of example, data from a human lymphoid cancer model are shown in Figure 6. Mice treated with vehicle showed rapid tumor growth; in contrast, animals treated with Marqibo demonstrated dose-dependent tumor suppression at 1.0, 1.5, and 2.5 mg/kg doses. Page 36

37 Marqibo (vincristine sulfate liposomes injection) Figure 6. Anti-Tumor Activity of Marqibo by Dose Doses of Marqibo = vincristine component. * Namalwa Tumors in Female CB17 SCID mice following IV administration on days 11, 18 and 25 postimplantation. In 18 tumor models representing 11 tumor types, Marqibo had generally improved antitumor activity compared to equivalent doses of vincristine in most of the tumor models and in no case did it exhibit reduced antitumor activity at the same dose. Figure 7 shows the potent findings by dose on tumor volume. Marqibo provided greater tumor growth suppression than equal doses of vincristine and had a maximal effect at its MTD of 2.5 mg/kg. Page 37

38 Marqibo (vincristine sulfate liposomes injection) Figure 7. Anti-Tumor Activity of Marqibo vs. Standard Vincristine 4.3 Clinical Pharmacokinetics of Marqibo Given that Marqibo delivers vincristine encapsulated in a liposomal carrier, plasma pharmacokinetics (PK) of encapsulated (total) vincristine are primarily governed by PK of the liposomes. The primary route of liposome clearance (Cl) from the blood is via uptake by cells of the MPS (Hwang 1987, Allen and Stuart 1999). These phagocytic cells are primarily located in the liver, spleen, and lymph nodes, with the liver representing the most important site based on its size. The rate of liposome clearance from the blood is dependent on various liposome physical parameters (Hwang 1987, Allen and Stuart 1999) and on the capacity and/or activity of the MPS. For example, nonclinical studies have shown faster rates of liposome clearance at lower administered doses (Allen and Stuart 1999), which may reflect saturation of MPS uptake as the liposome dose is increased. Further, it is well established that liposome clearance rates can be greatly decreased by inhibition of phagocytic activity (Camilleri et al 1995). Given the sensitivity of liposome clearance rates to the capacity and activity of the MPS, it would not be surprising that considerable interpatient variability would be seen in this process Bioavailability Measurement of the concentration of total vincristine in plasma does not distinguish between encapsulated vincristine (i.e., entrapped within the liposome) and vincristine that has been Page 38

39 Marqibo (vincristine sulfate liposomes injection) released from the liposomes. Interactions between vincristine and metabolic enzymes or its pharmacological target, tubulin, cannot occur when the drug is sequestered within the liposome. Although Marqibo is administered IV, almost all of the vincristine (>97%) is initially encapsulated within the SM-based liposomal carrier and hence is not immediately bioavailable for cellular uptake (with the exception of uptake by phagocytic cells). Consequently, the rate and extent of vincristine release from the liposomes, as well as the rate of distribution of the Marqibo liposomes to the tumor and tissues are important in understanding the bioavailability of drug in plasma. As part of the characterization of Marqibo, in vitro studies (IVR) were conducted to measure the release of vincristine from Marqibo in human plasma as a guide to interpretation of PK data obtained in subjects. The data show that the rate of vincristine release is slow, with just 18-39% of the drug released over a 24-hour period. Although the rate of release of vincristine from Marqibo has not been studied directly in humans, clinical PK studies (VSLI-11-PHARM, VSLI-13-COMPHARM, HBS408, and CA99002) showed that vincristine remains encapsulated for extended periods after Marqibo administration in humans. The plasma concentration of released (free) vincristine is below the lower limit of quantification (LLOQ) at most time points in all subjects (>95% of samples), suggesting that the vincristine measured in the plasma is encapsulated in Marqibo. Thus, the plasma PK parameters reported for total vincristine reflect those of encapsulated drug. Considered with the IVR results, these data indicate that Marqibo performs as a slowrelease formulation of vincristine. The plasma PKs of total vincristine are primarily governed by PK of the liposomes and the majority of vincristine is cleared from the circulation in an encapsulated form rather than being released into the circulation. Since plasma protein binding has been shown to affect drug release rates and clearance in other liposomal systems, the extent of binding of human plasma proteins to Marqibo was assessed in vitro and found to be below the detection limit of the analytical methods available. The extent of binding to plasma proteins of vincristine released from Marqibo has not been directly measured. However, published reports indicate 49-68% vincristine binding to human plasma proteins. The protein binding to vincristine released from Marqibo is not expected to differ from that after standard vincristine administration Distribution Table 3 summarizes PK parameters for total vincristine after Marqibo administration. The overall mean V ss value of 2606 (range: ) ml in the primary studies is similar to Page 39

40 Marqibo (vincristine sulfate liposomes injection) plasma volume in adults (3000 ml), indicating that Marqibo is mainly confined within the plasma compartment, consistent with vincristine encapsulation in slow-release liposomes. Table 3. Summary of Total Vincristine PK Parameters after Marqibo Administration Study Type Primary (Adult) Primary (Children) Supportive (Adult) n C max (ng/ml) ± 324 (29) ± 608 (32) ± 223 (20) t 1/2λ0 a (h) 2.4 ± 0.7 (28) 3.0 ± 0.3 (11) 4.9 ± 2.3 (48) t 1/2λ1 (h) 11.4 ± 5.8 (51) 15.1 ± 0.1 (1) 21.9 ± 7.7 (35) AUC inf (h ng/ml) ± (74) ± 7145 (39) ± (71) V ss (ml) 2606 ± 1089 (42) 720 ± 97 (14) 3176 ± 995 (31) Cl (ml/h) 381 ± 198 (52) 111 ± 3 (3) 310 ± 226 (73) Primary studies are VSLI-11-PHARM, VSLI-12, VSLI-13 CA99002 and HBS-407 (adults), and P (children). Supportive studies are CA95001 and CA Mean values are shown ±SD (%CV). Maximum concentration (C max ) and AUC inf data are from VSLI-11, VSLI- 13, and CA99002 due to the different doses in VSLI-12 and HBS-407. Note: If the decline appeared to be biexponential the half-life of the initial slope is denoted by t 1/2λ0, representing a relatively brief and rapid clearance of drug-loaded liposomes, while the half-life of the terminal slope was denoted by t 1/2λ1, which represents the dominant portion of the circulation half-life. Both these phases represent clearance of drug-loaded liposomes from the plasma compartment to the tissues. a. t 1/2λ0 values are only available for subjects showing apparent biexponential profiles Metabolism Vincristine released from the liposomes of Marqibo is expected to be metabolized at cellular and biochemical levels in the same way as vincristine. Additional studies were conducted to specially evaluate Marqibo s effect on vincristine metabolism. In Study VSLI-11-PHARM, 7.0% of the administered dose was excreted in the urine as unchanged vincristine over 96 hours. Trace quantities of N-desformylvincristine (<1%) were also detected, although this may arise also as an impurity in Marqibo. These values were similar over the range of mono- and biexponential plasma PK profiles. The findings with Marqibo were consistent with published reports concerning the degree of vincristine metabolism in humans after vincristine administration, although this is not well characterized and varies greatly between individuals (Bender et al 1977, Jackson et al 1978, Balis et al 1983). A study in non-hodgkin s lymphoma subjects showed that within 72 hours following injection of [3H]-vincristine, 46% and 40% of the radioactivity recovered in urine and feces, respectively, was recovered as metabolites of vincristine (Bender et al 1977). In this study, at least 34% of the injected dose was excreted as metabolites. Analysis of the urine from 5 Page 40

41 Marqibo (vincristine sulfate liposomes injection) subjects receiving vincristine showed that the concentration of metabolites (and/or degradation products) was in the range of 2% to 30% compared to 30% to 70% for the parent compound (Sethi et al 1981a). In summary, the limited data available from examination of urine samples from Marqibo - treated subjects suggest that liposome encapsulation of vincristine does not alter the extent of vincristine metabolism Elimination The drug concentration-time profiles of total vincristine following Marqibo administration show common features of an initial delay in clearance, which varies from 3-12 hours after the end of infusion, after which the total vincristine plasma concentrations begin to decline (Figure 8). In all subjects, the delay in clearance of total vincristine from plasma contributes to the increased AUC compared with vincristine administration (Section 4.3.5). Following the delay phase, plasma concentrations decreased with either an apparent monoexponential or an apparent biexponential profile. The latter comprise a relatively rapid decline phase, primarily representing the rapid clearance of drug-loaded liposomes from plasma, followed by a slower phase with a half-life similar to that observed in subjects exhibiting monoexponential profiles. These findings are consistent with a relatively long circulation half-life for Marqibo and slow release of encapsulated vincristine. In contrast, C max, circulation half-life (t 1/2λ1 ), and V ss are less variable among subjects (Table 3). The greatest contribution to the intersubject variability appears to be in the extent to which a rapid clearance phase occurs, which varies from undetectable in some subjects (i.e., those with monoexponential profiles) to being a major feature of the profile in others, leading to the appearance of biexponential profiles. These observations of intersubject variability are believed to result from variations between individuals in the level of capacity and/or degree of clearance activity of the MPS. Page 41

42 Marqibo (vincristine sulfate liposomes injection) Figure 8. Mean Total Vincristine Plasma Concentration-Time Profile (HBS407, N=13) Total Vincristine Plasma Concentration (ng/ml) Time From Start of Infusion (hr) Source: Figure 5, Module Although interindividual variability is high, plasma clearance profiles within individual subjects are consistent upon repeated exposure to Marqibo. There is no evidence of plasma accumulation of the drug when administered at 14-day intervals and there is no consistent alteration in AUC or Cl between Cycle 1 and Cycle 3 of treatment (Talon, Data on file). Table 4 shows that the variability in PK parameters with Marqibo is similar to that reported for other approved liposomal agents. Page 42

43 Marqibo (vincristine sulfate liposomes injection) Table 4. Comparison of Coefficient of Variance (%) for Various PK Parameters for Marqibo and Other Liposomal Drug Products Approved in the US, Canada, and Europe Product AUC inf (%CV) t 1/2 termination (%CV) Cl (% CV) V ss (% CV) Marqibo a Doxil b 9-51 b b 4-39 b Myocet b b b b DaunoXome NR NR AmBisome b b b b a. Studies VSLI-11-PHARM, CA99002, CA95001, CA b. Range shown represents the minimum and maximum values for coefficient of variation (% CV) reported in the referenced studies. NR = Not reported Vincristine PK: Marqibo vs. Standard Vincristine Formulation Figure 9 shows the mean plasma concentration of total vincristine (and profiles for a slowand fastest-clearing adult subject) following single dose Marqibo 2 mg/m 2 compared to standard vincristine 1.2 mg/m 2, with levels substantially higher following Marqibo over the ~70 hour period following dosing. Page 43

44 Marqibo (vincristine sulfate liposomes injection) Figure 9. Plasma Concentrations of Total Vincristine a Over Time Following Single Dose Marqibo 2.0 mg/m 2 and Standard Vincristine Figure shows data for the slowest-clearing (Subject 010) and the fastest-clearing (Subject 001) Marqibo -treated adult subjects in study VSLI-11, the mean of subjects in the VSLI-11 and CA99002 studies, and published PK data for vincristine (Nelson RL1982). a. Total vincristine includes encapsulated and released vincristine; released vincristine remains low with Marqibo. Table 5 presents PK parameters for total vincristine following Marqibo and standard vincristine administration in adults. Compared to the PK of vincristine after standard vincristine administration, the AUC and t 1/2λ1 of total vincristine in plasma after Marqibo administration are substantially increased in all subjects, while clearance is substantially reduced. The V ss for total vincristine after Marqibo infusion is similar to plasma volume in all subjects, indicating that Marqibo is mainly confined within the plasma compartment, whereas V ss for vincristine after standard vincristine administration is very high, reflecting widespread tissue distribution. Vincristine accumulates in phagocytic tissues, including spleen, liver, lymph nodes, as well as nerve and cardiac tissues Page 44

45 Marqibo (vincristine sulfate liposomes injection) Table 5. Summary of Total Vincristine PK Data Following Marqibo and Standard Vincristine Administration in Adults Marqibo (Primary) n=23 Marqibo (Primary) n=12 Marqibo (Supportive) n=13 Standard Vincristine n=99 a Dose (mg/m 2 ) C max (ng/ml) ( ) ( ) ( ) (80-822) t 1/2λ0 (h) ( ) t 1/2λ1 (h) ( ) N/A 7.7 ( ) ( ) ( ) N/A ( ) t 1/2λx (h) AUC inf (h ng/ml) N/A ( ) N/A ( ) N/A ( ) ( ) (9-1259) V ss (ml) ( ) 2914 ( ) ( ) ( ) Cl (ml/h) (96-770) 345 ( ) (73-816) ( ) The values represent ranges of mean values from individual studies listed in Supplemental Table 33 located in Appendix E, whereas the values in parentheses indicate the ranges observed for individual subjects among the studies. For ease of comparison of PK data among studies, the units for various PK parameters for vincristine were converted to those shown in the table using the information provided in each publication. Primary studies are VSLI-11-PHARM, VSLI-13 COMPHARM and CA99002 at 2 mg/m 2 and HBS-407 at 2.25mg/m 2. Supportive studies are CA95001 and CA N/A = Not applicable. a. Not all the PK parameters listed here are reported in all the publications reviewed. The number of subjects used to report the range for each PK parameter are as follows: C max (n=27), t 1/2λ1 (n=55), t 1/2λz (n=100), AUC inf (n=83), V ss (n=47), and Cl (n=64) Special Populations Comparison of PK parameters between subjects with different cancer indications revealed no differences correlating with disease type. The impact of hepatic impairment on the PK of Marqibo was evaluated in a study of subjects with melanoma and impaired hepatic function (VSLI-12 HEPHARM). Calculated PK parameters were similar in subjects with impaired liver function compared to those in subjects with adequate liver function: The mean dose adjusted AUC, t 1/2, time to maximum concentration (T max ), C max, and V ss in these subjects with moderately impaired liver function were similar to those in subjects with normal liver function (VSLI-11) (Bedikian et al 2010). After adjusting for the difference in dose, no statistically significant differences between the hepatic-impaired subjects versus those with normal liver function were observed in the exposure AUC inf (p=0.81), t 1/2 (p=0.16), Cl (p=0.84), or V ss (p=0.36). Subjects with impaired liver function universally had a monoexponential total plasma vincristine concentration Page 45

46 Marqibo (vincristine sulfate liposomes injection) versus time decline, whereas two-thirds of subjects with adequate liver function had a biexponential decline profile. Because one-third of subjects with normal hepatic function also demonstrated monoexponential declines, the absence of biexponential declines in the hepaticimpaired subjects cannot be unequivocally attributed to liver impairment. However, to be consistent with current practice for vincristine, the proposed Package Insert for Marqibo will recommend a 50% reduction in Marqibo dose (i.e., to 1 mg/m 2 ) for subjects with hepatic impairment. Page 46

47 Marqibo (vincristine sulfate liposomes injection) 5. Overview of Marqibo Clinical Development Program 5.1 Regulatory History Inex Pharmaceuticals, now known as Tekmira Pharmaceuticals, submitted the Investigational New Drug application (IND 59,056) for Marqibo to the FDA on September 30, A New Drug Application (NDA ) seeking accelerated approval of the indication, treatment of patients with aggressive non-hodgkin's lymphoma that is refractory to, or relapsed after two prior combination chemotherapy regimens was submitted to FDA on September 29, In December 2004, the Oncologic Drugs Advisory Committee (ODAC) voted unfavorably regarding whether Marqibo data demonstrated superiority over other potential therapies in relapsed aggressive NHL following at least two prior chemotherapies. Additionally, the FDA found that subjects were enrolled in the pivotal study who did not meet the study s eligibility criteria as well as additional concerns with the conduct of the supporting study. Inex received a non-approvable action notification on January 14, Hana Biosciences, now known as Talon Therapeutics, acquired development rights to Marqibo from Inex on May 6, All pending FDA requests for follow-up information and responses to questions that were forwarded to Inex following the non-approvable action were addressed in various IND submissions filed by Talon in 2010 and Talon has held five meetings with the Agency regarding the clinical development program of Marqibo that seeks accelerated approval for the indication, treatment of Ph- adult ALL in patients in second or greater relapse or whose disease has progressed following 2 or greater anti-leukemia therapies, including: October 31, 2006 Type B Clinical meeting: Marqibo proposed Phase 2 study design discussed. June 27, 2007 Type A SPA meeting: Agreement that Marqibo qualifies for Fast Track Designation and general agreement with Talon Phase 2 (HBS407) and Phase 3 (HBS404 now known as TTX404) plans. Monotherapy was discussed as a means to isolate Marqibo benefit (without confounding factors). All FDA questions were answered and FDA recommendations were implemented. Page 47

48 Marqibo (vincristine sulfate liposomes injection) March 26, 2010 Type C Clinical meeting: FDA and Talon discussion of DSHNHL lymphoma study as confirmatory trial, agreed with Agency on QT/QTc assessment plan, and that a clinical assessment of mass balance was not required. April 20, 2010 Type B Clinical pre-nda meeting: Agreement that Study HBS407 data presented at the meeting continue to support existing Fast Track designation; various aspects of the proposed NDA contents and presentation were discussed. November 8, 2010 Type B pre-nda meeting: Content and format of proposed NDA discussed. August 26, 2011 SPA for Study TTX404 granted by FDA. On August 26, 2011, full agreement was reached with the Agency on the TTX404 SPA. The confirmatory Study TTX404 entitled, A phase 3, multicenter, randomized study to evaluate the substitution of Marqibo (Vincristine Sulfate Liposomes Injection, VSLI) for standard vincristine sulfate injection (VSI) in the induction, intensification, and maintenance phases of combination chemotherapy in the treatment of subjects 60 years old with newly diagnosed acute lymphoblastic leukemia (ALL) is ongoing (refer to Section 7). 5.2 Clinical Dose Selection and Strategy for Dose Reduction to Limit Toxicity To determine the MTD, the first phase of VSLI-06, a Phase 1/2, multicenter, open-label, study, was conducted as a dose escalation study of Marqibo combined with pulse dexamethasone in subjects with relapsed or refractory ALL and measurable disease. VSLI-06 included a paradigm for dose reduction in response to toxicity. Up to 7 Marqibo escalating dose cohorts (i.e., 1.5, 1.825, 2.0, 2.25, 2.4, 2.6, and 2.8 mg/m 2 infused IV over 60 minutes) were to be investigated sequentially, with escalation to the next higher Marqibo dose cohort allowed to proceed only if there was an absence of nonhematologic dose-limiting toxicities (DLT) observed. In order to be included in the MTD evaluation, subjects had to receive at least 1 course of Marqibo, consisting of 4 weekly infusions at the assigned dose with a 2-week minimum observation after the last Marqibo dose. Subjects who received fewer than 4 infusions were replaced for the MTD evaluation. The criteria for determining the MTD and for dose reduction to limit toxicity in Study VSLI-06 are presented in Appendix A. Page 48

49 Marqibo (vincristine sulfate liposomes injection) During dose escalation, 3 subjects in the 2.4 mg/m 2 dose group experienced DLTs (as defined in Appendix A). Two subjects experienced nervous system-related events, and 1 subject experienced a hepatic-related event. Subject 119 experienced motor neuropathy of Grade 3 on Study Day 42. Subject 124 experienced a grand mal seizure Grade 4 on Study Day 10. Subject 301 experienced elevated AST and hyperbilirubinemia Grade 4 on Study Day 18. No dose limiting toxicities seen in any of the 18 subjects dosed at 2.25 mg/m 2. On the basis of the number of subjects in the 2.4 mg/m 2 dose group that experienced DLTs, 2.25 mg/m 2 was determined to be the MTD and the dose to evaluate in Study HBS407. In addition, clinical assessment found no pattern of excessive or unacceptable toxicity, suggesting that the dose delay/reduction strategy used in VSLI-06 was effective, and was utilized in HBS Overview of Studies HBS407 and VSLI-06 - Efficacy Component The efficacy of Marqibo was studied in two studies (HBS407 and VSLI-06) that enrolled 101 subjects with advanced, relapsed and/or refractory adult Ph- ALL. HBS407 was conducted in the U.S. (82% of enrolled subjects), Canada, Germany, and Israel. VSLI-06 was conducted in the U.S. HBS407 provides confirmatory efficacy data in adult Ph- ALL subjects (mostly third-line or greater or refractory) who were treated with single-agent weekly Marqibo 2.25 mg/m 2. The Intent-to-Treat (ITT) Population included 65 subjects. VSLI-06 was a MTD study of a more heterogeneous population that allowed for an examination of efficacy with 2.25 mg/m 2. The study design, methodology, and efficacy results of these clinical studies are summarized in Table 6 and reviewed in more detail in the following sections. Page 49

50 Table 6. Summary of Studies HBS407 and VSLI-06 Study Identifier Type of Study HBS407 Safety Efficacy VSLI-06 Safety Efficacy Dose ascending Primary Objective(s) of the Study Rate of complete response (CR) plus CR with incomplete blood count recovery (CRi). 1) To determine the maximum tolerated dose (MTD) of Marqibo given with pulse dexamethasone. 2) To determine the efficacy of Marqibo given with pulse dexamethasone. Study Design and Type of Control Phase 2, international, multicenter, open-label, single-arm study. Phase 1/2, multicenter, open-label, dose escalation study. Test Product(s); Dosage Regimen; Route of Administration Single-agent Marqibo administered at 2.25 mg/m 2 as an IV infusion (peripheral or central venous access) over 1 hour (±10 minutes) every 7 days on Days 1, 8, 15, 22 (±3 days), but no less than 4 days apart. Four weekly doses constituted one course. Marqibo (7 dose cohorts: 1.5, 1.825, 2.00, 2.25, 2.4, 2.6 and 2.8 mg/m 2 ) infused IV over 1 hour on Days 1, 8, 15, and 22 (±2 days) and dexamethasone 40 mg daily orally or IV on Days 1 to 4 (±2 days) and Days 11 to 14 (±2 days). Four weekly doses of Marqibo and dexamethasone constituted 1 course of therapy. Number of Subjects Treated Diagnosis of Subjects 65 subjects Adult subjects with Philadelphia chromosomenegative ALL: 1) who were in second relapse or who failed 2 treatment lines of antileukemia chemotherapy 2) who achieved a complete response to at least one prior anti-leukemia therapy as defined by a leukemia-free interval of 90 days. Previous stem cell transplantation was considered a treatment line of anti-leukemia chemotherapy. All Dose Cohorts: 36 subjects (24/12) 2.25 mg/m 2 Dose Cohort: 18 subjects Subjects with previously treated, relapsed or refractory ALL (including lymphoblastic lymphoma or Burkitt s-like subtypes) with measurable disease. Demographics Sex (Male/Female) Race (White/Other) Median Age (years) ITT Population 33M/32F 56/ All Dose Cohort: 24M/12F 18/ mg/m 2 Dose Cohort: 13M/5F 9/ Primary Efficacy Results A total of 13 subjects (20.0%; 95% CI: 11.1, 31.8) achieved CR+CRi based on PI assessment of the ITT Population N = 65; 11 subjects achieved CR+CRi based on IRRC determination.. The MTD for Marqibo was 2.25 mg/m 2. Marqibo was generally well tolerated in this heavily pretreated subject population. The CR plus PR response rate was 22.2% (4/18) in the 2.25 mg/m 2 cohort and 22.2% (8/36) overall, suggesting that Marqibo may offer benefit for subjects with relapsed or refractory ALL. Page 50

51 5.4 Study HBS Study Design Study HBS407 was a Phase 2, international, multicenter, open-label, single-arm trial evaluating Marqibo in adult ( 18 years of age) subjects with near end-stage, advanced, relapsed and/or refractory Ph- ALL (diagnosis confirmed by a central laboratory) (Figure 10). The study was conducted at 22 centers in United States, Canada, Germany and Israel. Subjects were required to have been treated with at least two prior therapies. Figure 10. HBS407 Study Schema ALL = acute lymphoblastic leukemia; BM = bone marrow; CR = complete remission; CRi = complete remission with incomplete blood count recovery; FU = Follow-up; HI = hematologic improvement; PR = partial remission; HSCT = Hematopoietic stem cell transplantation; SD = stable disease Source: HBS407 CSR Appendix , Protocol Amendment 5, Figure 2. Single agent treatment allows for isolation of the Marqibo treatment effect. Eligible subjects must have achieved a CR to at least 1 prior anti-leukemia chemotherapy (i.e., had multiple prior standard vincristine exposures), defined by a leukemia-free interval of 90 days. Previous HSCT was considered a treatment line of anti-leukemia chemotherapy. The primary objective of this study was to evaluate the efficacy of Marqibo as determined by the rate of CR plus CR with incomplete blood count recovery (CRi) in study subjects. Page 51

52 The secondary objectives of this study were to evaluate the duration of CR plus CRi, overall survival, as well as safety and tolerability. Eligible subjects received single-agent IV Marqibo at 2.25 mg/m 2, calculated based on actual BSA using the subject s height (from Screening) and actual weight for each course (no dose cap). The dose was administered via peripheral or central venous access over 60 minutes (±10 minutes) every 7 days (±3 days) (i.e., on Days 1, 8, 15, and 22), with no less than 4 days between dosing. Study drug was administered in an inpatient or outpatient setting at the discretion of the primary investigator (PI). Four weekly doses of Marqibo constituted 1 course of study treatment. Response assessments were completed on Day 28 of each course. Subjects who showed disease progression at any point were discontinued from the study. Those subjects who showed a CR, CR with incomplete hematologic recovery (CRi), bone marrow blast (BMB) response (i.e., morphologic remission without blood platelet count and neutrophil recovery), partial remission (PR), hematologic improvement (HI), or stable disease (SD, e.g., no significant hematological and extramedullary change from baseline) were eligible for continued Marqibo treatment until HSCT, disease progression, drug intolerability, or the PI determined that Marqibo treatment was no longer beneficial Subject Population Selection and Exclusion Criteria Subjects were enrolled into this single-agent Phase 2 study because of anticipated intolerance of multi-agent therapy (e.g., poor marrow reserves or poor performance status), refractoriness to prior multi-agent therapy, relapse following multi-agent therapy, and a relatively short remission duration. They were allowed to have undergone, and progress following, prior HSCT, which was counted as a prior line of antileukemia therapy. All Study HBS407 subjects were heavily pre-treated and all had received prior standard vincristine as a component of their prior ALL therapies. Because of this expectation of universal prior standard vincristine exposure, subjects were allowed to enter Study HBS407 with a past history of and residual signs and/or symptoms of standard vincristine-induced neuropathy, including constipation. Participation in Study HBS407 required that subjects not be eligible for immediate HSCT at the time of study screening and enrollment. Sources of ineligibility for immediate HSCT included insufficient time to identify, harvest, and deliver an HSCT. Taken together, these criteria were designed to attain an advanced, heavily pre-treated, near end-stage, relapsed and/or refractory adult ALL population of subjects in need of therapy. Page 52

53 5.4.3 Dose Reductions and Temporary Suspension of Dosing In Study HBS407, subjects were evaluated before each scheduled dose of Marqibo for possible toxicities that may have occurred after the previous dose(s). In this regard, a 15- point neurological assessment was performed to identify peripheral neuropathy, since this is a well-known vincristine-related adverse event that is linked to cumulative vincristine exposure. Up to 3 dose reductions were allowed for study drug-related non-hematologic toxicities. The dose reduction/delay schema for study drug-related non-hematologic toxicities utilized in Study HBS407 is presented in Appendix B Subject Follow-up and Schedule of Visits and Procedures Subjects attended study center visits at Screening (within 21 days prior to first Marqibo administration); during Study Drug Treatment on each dosing day (every 7 days [± 3 days], on Days 1, 8, 15, and 22); and at End-of-Therapy (30 days [+ 5] days after the last dose of Marqibo ). Before each scheduled dose of Marqibo, subjects were evaluated for possible toxicities that may have occurred after the previous dose(s). Special attention was paid to signs and symptoms potentially suggestive of neurotoxicity at each weekly visit. Bone marrow aspirate and biopsy assessments were completed on Day 28 of a study treatment course. If at any time a CR or CRi was documented in a bone marrow (BM) assessment, the subject continued study treatment and a confirmatory bone marrow aspirate and biopsy assessment were performed 4 weeks later on Day 28 of the next study treatment course. Thereafter, these subjects in CR or CRi underwent bone marrow aspirate and biopsy assessments at the end of every second course of study treatment (Day 28, ± 3 days) up to 6 months after the initial CR or CRi assessment. After 6 months, bone marrow aspirate and biopsy assessments were performed at the end of every third course of study treatment (Day 28, ± 3 days). If at any time a PR, HI, or SD was documented in a bone marrow assessment, the subject could continue study treatment and a bone marrow aspirate and biopsy assessment were performed 4 weeks later on Day 28 (± 3 days) of the next study treatment course. If at any time disease progression was documented based on bone marrow findings, the subject was discontinued from study treatment. If extramedullary disease was present at Screening and/or Course 1 Day 1, imaging and/or biopsy of involved sites were followed the same schedule as outlined for bone marrow aspirate and biopsy assessments. Subjects who, at the time of discontinuation from study treatment, did not show CR or CRi, completed the End-of-Therapy Visit. They were followed monthly for survival from the Endof-Therapy Visit through Month 12, then every 3 months through Month 24, and every 6 months through Month 60. Page 53

54 Subjects who, at the time of discontinuation from study treatment, showed CR or CRi completed the End-of-Therapy Visit and were followed for CR or CRi duration and any subsequent anti-leukemia therapy monthly from the End-of-Therapy Visit through Month 12 or until relapse if it occurred before Month 12. In addition, these subjects were also followed for survival every month from the End-of-Therapy Visit through Month 12, then every 3 months through Month 24, and after that, every 6 months through Month Primary Endpoint The response criteria used for the primary and secondary efficacy endpoints were consistent with those in recent clinical trials of ALL (Kantarjian et al 2000). The primary efficacy endpoint of Study HBS407 was the proportion of subjects who achieved CR plus the proportion of subjects who achieved CRi, as determined by the PI. CRi was included because patients were expected to be heavily pre-treated and possibly permanently cytopenic. In addition, lack of blood cell count recovery should not prevent or discourage physicians from providing patients transplants as soon as their leukemia was cleared. CR and CRi were also corroborated by an IRRC and were used to affirm the PI assessment. The IRRC, comprised of 3 leukemia experts (2 reviewers and 1 adjudicator) independently (and blinded to the PI response assessment) determined the final response category and important milestone dates (e.g., first CR or CRi date, relapse date, HSCT date, and death date), by assessing (1) blood and central bone marrow histologic reported data (biopsies/aspirates), (2) extramedullary disease data (magnetic resonance imaging/computed tomography) and (3) laboratory data. With these data, the individual IRRC reviewers provided an independent response assessment and determination, or confirmation, of milestone dates based on the protocol-specified and International Working Group (IWG) criteria (shown below). Any discrepancies of response category between the 2 IRRC reviewers were referred to the third IRRC member, who adjudicated a final response determination. The response definitions for CR and CRi were based on the IWG criteria (Madrid, Spain; 23 to 25 Mar 2001) for Diagnosis, Standardization of Response Criteria, Treatment Outcomes, and Reporting Standards for Therapeutic Trials in Leukemia (Cheson et al 2003): Page 54

55 Complete remission (CR): Normalization of the peripheral blood and bone marrow with 5% or fewer blasts in a normocellular or hypercellular marrow and a granulocyte count of /L or above and a platelet count of /L or above. Complete resolution of all sites of extramedullary disease was required for CR. Complete remission with incomplete blood count recovery (CRi): As per CR but platelet count < /L or ANC < /L Secondary Endpoints The secondary efficacy endpoints of Study HBS407 were: PI- and IRRC-determined best response categories CR, CRi, partial remission (PR), stable disease (SD), and progressive disease (PD) (IWG criteria) IRRC-determined BMB response Response duration based on IRRC-determined first response dates (CR and CRi only) (IWG criteria) and IRRC-determined relapse date (non-iwg criteria) following CR plus CRi IRRC-determined time to CR or CRi (IWG criteria) Overall survival (IWG criteria) Leukemia-free survival Time to peripheral blast clearance Time to bone marrow blast clearance Time to extramedullary disease clearance Number and proportion of subjects who received post-marqibo HSCT. The response definitions for PR, SD, and DP were based on the IWG criteria, as follows (Cheson et al 2003). Partial remission (PR): CR with 5% to 25% abnormal cells in the marrow or 50% decrease in bone marrow blasts. Reduction in extramedullary disease by at least 50% (sum of product, bi-perpendicular dimensions when available; no new lesion/no appearance of new disease). Stable disease (SD): No significant hematological and extramedullary change from baseline: Page 55

56 Stable complete blood count (CBC), differential and platelet count. No significant change in bone marrow blast count. Stable extramedullary disease: For measurable extramedullary disease: no new lesion(s) and either < 50% decrease in size of existing lesions or < 25% increase in size of existing lesions (<50% increase in size of existing lesion if only 1 lesion available and its nadir is 2 cm 2 in size). For non-measurable extramedullary disease including effusions and cerebrospinal fluid: no appearance of new disease. Disease progression: Hematologic worsening from baseline or progression of extramedullary disease: Investigator judgment of worsening CBC, differential or platelet counts, or increase in bone marrow blast count. Progression of extramedullary disease: For measurable extramedullary disease: appearance of new lesion(s) and/or 25% increase in size of existing lesions ( 50% increase in size of existing lesion if only 1 lesion available and its nadir is 2 cm 2 in size). For non-measurable extramedullary disease including effusions and cerebrospinal fluid: appearance of new disease Analysis Populations Efficacy in Study HBS407 was assessed in ITT population. The ITT analysis population included all subjects who had received at least 1 dose of Marqibo infusion and had histologically proven ALL, which was confirmed by a central hematopathologist Statistical Methods A Simon's 2-stage minimax design was used for this study. Assuming a null hypothesis that the CR/CRi rate is 10% (a response rate that is unlikely to be achieved in the study population based on historical data [O Brien et al 2008]) versus an alternative hypothesis that the true CR/CRi rate is 20%, fewer than 3 CR+CRi in a first stage of 29 evaluable subjects would lead to study termination. If there were 3 or more CR+CRi, additional subjects would be accrued until 9 CR+CRi or up to 56 total (first plus second stage) evaluable subjects. Page 56

57 Achievement of 9 CR+CRi in 56 subjects (16 %, [95% CI 7.6, 28.4]) was the pre-defined threshold for a positive study and excluded a 7.5% or lower CR+CRi rate. For this design, the alpha was set at 0.10 and the power was 80%. The study protocol was later amended to increase the sample size from 56 to 65 in order to accommodate the collection of pharmacokinetic data. The primary efficacy endpoint was summarized as the proportion of subjects who achieved CR or CRi (designated as CR+CRi). An exact 2-sided 95% confidence interval (CI) was constructed around the estimated CR+CRi proportion. Separate summaries were provided for PI determined CR+CRi responses and IRRC determined CR+CRi responses. The ITT Population was used for the evaluation of efficacy. The CR+CRi rate was calculated and exact 95% CIs [P lower,, P upper ] based on the binomial distribution was constructed by the Clopper-Pearson method (Clopper et al 1934) as: P lower = β -1 (0.025,n,N n + 1) P upper = β -1 (0.975,n+1,N - n) where β -1 (x,a,b) was the inverse beta function at x with parameters a and b, n was the number of subjects with a response and N was the number of subjects included in the analysis set. This was calculated using the FREQ procedure in SAS with the BINOMIAL option in the TABLES statement Clinical Efficacy Demographic Baseline Characteristics Table 7 shows baseline demographic characteristics of study subjects for the ITT population. Subjects ranging in age from 19 to 83 years were treated in this study. At baseline, mean (± SD) weight was 77.8 kg (± 19.3) and median BSA was 1.89 m 2. Page 57

58 Table 7. Demographic Characteristics: Study HBS407 Variable at Baseline HBS407 (ITT) (N = 65) Gender [n (%)] Female 32 (49.2) Male 33 (50.8) Race [n (%)] White 56 (86.2) Black or African American 4 (6.2) Asian 2 (3.1) Other 3 (4.6) Ethnicity [n (%)] Hispanic or Latino 17 (26.2) Not Hispanic or Latino 48 (73.8) Age (years) Mean±(std dev) 36.3±(16.77) Median 31.0 Q1, Q3 25.0, 43.0 Min, Max 19, 83 Age Group [n (%)] years 29 (44.6) years 28 (43.1) 60 years 8 (12.3) Source: HBS407 CSR, Tables through Table 8 summaries baseline ALL clinical characteristics. Approximately 15% of subjects had T-cell lineage ALL. Two subjects were allowed into the study with relapsed ALL and < 10% bone marrow blasts because of biopsy positive extramedullary disease (lymphoblastic lymphoma-like relapse presentation). More than 20% of subjects had poor (Eastern Cooperative Oncology Group [ECOG] score 2) performance status at study entry. Extramedullary disease was present in more than 15% of subjects. Thrombocytopenia (platelet count /L) at study entry, a marker of poor response to third-line therapy in adult ALL (O Brien et al 2008), was present in more than half of study subjects. Page 58

59 Table 8. Baseline Characteristics: Study HBS407 Baseline Parameter HBS407 (ITT) (N = 65) Type of ALL (based on Central Reviewer), n (%) Precursor B-lymphoblastic leukemia 55 (84.6) Precursor T-lymphoblastic leukemia 10 (15.4) Time Since Diagnosis of ALL (years) a Mean (std) 2.7 ± (2.80) Median 1.8 Q1, Q3 1.0, 3.0 Min, Max < 1, 15 Extramedullary Disease, n (%) Yes 10 (15.4) No 55 (84.6) ECOG Performance Status, n (%) 0 17 (26.2) 1 33 (50.8) 2 11 (16.9) 3 4 (6.2) Platelet Count, n (%) /L 39 (60.0) > /L 26 (40.0) a (Date of first dose Date of diagnosis+1)/ Source: HBS407 CSR, Tables through , Tables through , and Table The majority of subjects displayed markers (CD10, CD19, CD20, and CD22) consistent with precursor B-cell ALL (HBS407 CSR, Table and Table ). CD13, CD15, and CD33 are commonly detected myeloid antigens in adult ALL, in contrast to childhood ALL, with reported incidences ranging from 15-54%. CD34, detected in 62%, is expressed more frequently in adults with B-lineage ALL and was reported to adversely affect outcome by the CALGB study group (Czuczman et al 1999). The majority of subjects with available data (59%) had unfavorable cytogenetics at baseline and none of the subjects had favorable cytogenetics (HBS407 CSR, Table and Table ). This pattern of cytogenetics is consistent with the relapsing and/or refractory disease natural history in these populations. Page 59

60 All subjects had been previously treated with standard vincristine and, in general, heavily pre-treated with other therapies. Subjects had already been exposed to a median of 9 and up to 15 different anti-leukemia drugs prior to Study HBS407. Importantly, most subjects (76.9%) were experiencing signs and/or symptoms of neuropathy at study enrollment, likely ongoing residual toxicity from prior treatment. Almost half of subjects (49.2%) received 2 lines of prior anti-leukemia treatment, followed by 24 subjects (36.9%) who received 3 lines, 8 subjects (12.3%) who received 4 lines, and 1 subject who received 6 lines of prior anti-leukemia treatment (Table 9). Almost all subjects (95.4%) achieved a CR as the best response to prior induction therapy. Three subjects (4.6%) had never achieved a past CR and posed an even greater challenge. The median duration of best response to prior induction therapy was approximately 11 months (334 days). Approximately half of subjects (31 of 65) had received prior HSCT (44.6% 1 prior HSCT, 3.1% 2 prior HSCT). Of these 31 subjects having prior HSCT, 27 were in remission as a component of remission consolidation therapy and 4 were a component of salvage therapy. Table 9. Prior Anti-Leukemia Therapy: Study HBS407 (ITT) Therapy Type ITT (N = 65) Number of Prior Lines of Anti-Leukemia Treatment (maximum per subject) 2 32 (49.2) 3 24 (36.9) 4 8 (12.3) 6 1 (1.5) Best Response to Prior Induction Therapy [n (%)] Complete Remission (CR) 62 (95.4) Progressive Disease (PD) 1 (1.5) No Response (NR) 1 (1.5) Unknown (UN) 1 (1.5) Duration of Best Response to Prior Induction Therapy (Days) N 65 Mean (std) ± (820.27) Min, Max 32, 4050 Prior HSCT [n (%)] None 34 (52.3) One Prior HSCT 29 (44.6) Two Prior HSCT 2 (3.1) Source: HBS407 CSR, Table and Table Page 60

61 Disposition and Dosing The number of consented subjects was 68 and 65 (95.6%) enrolled subjects received one or more doses of Marqibo. Treatment was ultimately discontinued in all 65 subjects (100%) in the ITT Population. The most common reason for study treatment discontinuation was disease progression (40.0%, 26/65), followed by AEs (36.9%, 24/65), investigator request (9.2%, 6/65), planned HSCT (7.7%, 5/65), and subject withdrew consent (6.2%, 4/65). Disease progression was reported, at times, even without bone marrow or extramedullary disease tissue biopsy to confirm actual progression of leukemia. Subjects with dosing modifications in the ITT population included those that had missed doses (24.6%), reduced doses (23.1%), and delayed doses (1.5%) (Table 10). Table 10. Summary of Dose Modifications in Study HBS407 (ITT) Variable (N=65) Subjects With Missed Doses 16 (24.6) 2.25 mg/m 2 14 (21.5) 2.00 mg/m 2 6 (9.2) mg/m 2 0 (0.0) Subjects With Reduced Doses 15 (23.1) 1 Reduction 10 (15.4) 2 Reductions 5 (7.7) Subjects With Delayed Doses 1 (1.5) 2.25 mg/m 2 0 (0.0) 2.00 mg/m 2 1 (1.5) mg/m 2 0 (0.0) Source: HBS407 CSR, Table Subjects in the ITT Population received a median of 4 doses of Marqibo (range 1-18) with median individual absolute dose size of 4.12 mg (range mg). The median dose size per kg was 0.06 mg/kg (range mg/kg). The median dose density was 2.25 mg/m 2 /week (range mg/m 2 /week). The median cumulative Marqibo exposure was mg (range mg). Marqibo dosing was not capped in this study, resulting in a median dose equivalent to 206% (range, 157%-276%) of the dose of standard vincristine. Page 61

62 Efficacy Results Clinical Response The ITT Population included all 65 enrolled subjects who received at least one dose of Marqibo. Twelve subjects were not evaluated by the IRRC because they lacked protocolspecified bone marrow examinations and other assessments sufficient to document a response or lack of response to Marqibo. The most common reason for this lack of assessment was death due to infection that occurred prior to the first scheduled assessment. Table 11 shows clinical response rates based on PI assessment in the ITT population. Based on the ITT Population and response assessments performed by the PIs, 20% (13/65) achieved a CR with or without complete peripheral blood count recovery (CR+CRi). There were 2 fewer (n=11) CR+CRi based on IRRC assessment, which were assessed as bone marrow blast (BMB) responses, which represent CR without recovery of both the neutrophil and platelet counts. The CR+CRi rate was based upon the IRRC assessment in the ITT population was 16.9% (11/65, [95% CI 8.7, 28.3]). Regardless, the lower bound of the 95% CI is greater than 7.5% when using either PI or IRRC assessment. For the 11 subjects (of 53, 20.8%) who achieved CR+CRi based on IRRC determination, 6 received prior HSCT, 4 had extramedullary disease at baseline, and 2 experienced a third relapse prior to entering the study. Page 62

63 Table 11. Clinical Response Assessment Study HBS407 Best Response Assessment PI (ITT) (N=65) IRRC(ITT) (N=65) Overall Response (CR+CRi) [n (%)] 13 (20.0) 11 (16.9) Exact 95% CI a (Clopper-Pearson) ( ) ( ) Complete Remission (CR) [n (%)] 7 (10.8) 8 (12.3) Exact 95% CI a (Clopper-Pearson) ( ) ( ) Complete Remission with Incomplete Blood Count Recovery (CRi) [n (%)] 6 (9.2) 3 (4.6) Exact 95% CI a (Clopper-Pearson) ( ) ( ) Partial Remission (PR) [n (%)] 6 (9.2) 4 (6.2) Exact 95% CI a (Clopper-Pearson) ( ) ( ) Bone Marrow Blast (BMB) [n (%)] 4 (6.2) 4 (6.2) Exact 95% CI a (Clopper-Pearson) ( ) ( ) Stable Disease (SD) [n (%)] 12 (18.5) 13 (20.0) Exact 95% CI a (Clopper-Pearson) ( ) ( ) Progressive Disease (PD) [n (%)] 20 (30.8) 21 (32.3) Exact 95% CI a (Clopper-Pearson) ( ) ( ) a Exact 95% confidence interval generated using the binomial distribution. Source: HBS407 CSR, Table Among subjects in the ITT Population, CR or CRi was achieved in 6 of 32 subjects (19%) who received Marqibo as third-line therapy, 5 of 24 subjects (21%) who received Marqibo as fourth-line therapy, and 2 of 9 subjects (22%) who received Marqibo as fifth-line or greater therapy. Marqibo resulted in CR or CRi in: 9 of 36 subjects (25%) in the setting of an untreated relapse; 4 of 29 subjects (14%) in the setting of a relapse that was refractory to 1 immediately prior relapse regimens (i.e., single agents such as clofarabine and multi-agent treatment regimens inclusive of vinca alkaloids); and, 13 of 50 subjects (26%) with ECOG performance score of 0 or 1. No subject with an ECOG performance score of 2 or 3 achieved CR or CRi. Table 12 shows the anti-leukemia therapies prior to enrollment in Study HBS407 for the 11 subjects who had a complete response (CR+CRi) based upon IRRC assessment. Page 63

64 Table 12. Prior Therapies of Subjects Who Achieved CR or CRi (IRRC Assessment) - Study HBS407 ID TxLINE1 RESP TxLINE2 RESP TxLINE3 RESP TxLINE4 RESP TxLINE5 HBS407 OUTCOME 3 CVAPM CR R EPfLann/HSCT CR R Marqibo CRi 4 CVAD CR R CVALasp CR BMe/HSCT CR R AracM NR Marqibo CR 10 CVADMpMP CR R CVDAracLasp CR BMe/HSCT CR R Marqibo CRi 31 IdaAracCDaunPVLaspMMp CR R CAracMMp CR R Marqibo CR 93 VPAracLaspMMp CR R VAPAracLasp CR E/HSCT CR R Marqibo CR 211 CVADAracM CR C/HSCT CR R Marqibo CRi 391 CVPDaunLaspAracA CR AracCM/HSCT CR R Marqibo CR 393 CVAD CR R Unk CR R Marqibo CR 692 VLaspDaunMMp CR R CVDDaunAracM CR R Cl PD Marqibo CR 694 CVA CR R CVADLaspM CR Unk/HSCT CR R Marqibo CR 781 VDLaspDaunMMp CR R LaspVCDaunAracIMpVb CR R VnMiArac NR Marqibo CR A = doxorubicin, Ac = actinomycin-d, Al = alemtuzumab, Arac = cytarabine arabinoside, Atg = anti-thymocyte globulin, B = busulfan, C = cyclophosphamide, Ca = carmustine, Ch = chlorambucil, Cl = clofarabine, Cp = cisplatin, D = dexamethasone, Daun = daunorubicin, E = etoposide, F = fludarabine, H = hydroxyurea, Hc = hydrocortisone, I = ifosphamide, Ida = idarubicin, Lann = L-annamycin, Lasp = L-asparaginase, M = methotrexate, Me = melphalan, Mi = mitoxantrone, Mp = 6-mercaptopurine, Mt = methylprednisolone, N = nelarabine, P = prednisone, Pf = Palifermin, Pn = prednisolone, R = rituximab, S = solumedrol, Sb = solambutol, T = teniposide, Tg = 6-thioguanine, Th = thiotepa, V = vincristine, Vb = vinblastine, Vd = vindesine, Vn = vinorelbine. CR = complete response CR R = complete response followed by a relapse NR = no response (refractory) PD = progressive disease (refractory) Unk = unknown because of unavailable data HSCT = hematopoietic stem cell transplant Source: Appendix B, SCE. Page 64

65 Marqibo also induced CR following dose reduction. As previously noted (Table 10), 15 of 53 subjects (28.3%) in the IRRC Evaluable Population had a dose reduction according to the protocol-specified dose reduction algorithm. Seven of these 15 subjects (46.7%) achieved CR or CRi. This demonstrates that Marqibo treatment can be individualized in a manner that maintains significant drug activity and efficacy response rates Secondary Endpoints Table 11 summarizes individual response assessments (CR, CRi, PR, BMB, SD, PD, and Not Evaluable) Durable Remission Of the 11 subjects who achieved CR+CRi, time to response ranged from 25 to 81 days, with 45.0% (5/11) achieving the remission within 35 days and 91% (10/11) within 57 days. The median time to CR+CRi was not observed in the treatment follow-up period (i.e., more than half of subjects did not experience CR+CRi by the time of treatment discontinuation or last on-treatment assessment). The median CR+CRi response duration was 23 weeks (95% CI: 18.9, 30.0), with a maximum duration of remission well over one year (66 weeks). This median duration of remission is more consistent with expectations for a population receiving second-line treatment (Thomas et al 1999) and not one composed primarily (92%) of subjects in need of third-line or greater treatment. For the 13 subjects in Study HBS407 who achieved CR+CRi per the primary analysis the median duration of remission was 23 weeks, with a maximum duration of remission well over one year (66 weeks). This median duration of remission, half that of the median duration of first remission, is more consistent with expectations for a population in need of secondline (first salvage) therapy (Thomas et al 1999) and not one entirely (100%) composed of subjects in need of third or greater line therapy. Additionally, the majority (9, 69%) of subjects in HBS407 who attained a CR+CRi from Marqibo had a response duration that exceeded the duration of response to their last line of ALL therapy. This pattern contrasts with the normal pattern of each subsequent response being significantly shorter than the previous response Overall Survival Figure 11 presents the Kaplan-Meier (K-M) plots of overall survival for both the ITT Population and IRRC Population. Page 65

66 Figure 11. Kaplan-Meier Plots of Overall Survival Study HBS407 Source: HBS407 CSR, Figure For the 65 subjects in the ITT Population, the overall survival rates were 89.2% (95% CI: 81.7, 96.8) at 1 month, 35.1% (95% CI: 23.3, 46.9) at 6 months, 8.0% (95% CI: 1.3, 14.7) at 12 to 18 months, and 4.0% (95% CI: 0.0, 9.1) at 24 months. Median overall survival was 4.6 months for the ITT subjects and 7.7 months (230 days; 95% CI: 163, 321) in those achieving CR+CRi (n = 13). Four subjects had overall survival in excess of 1 year and are potential long-term survivors as a result of Marqibo. An additional subject, not evaluable according to the IRRC, was a longterm survivor making the total in Study HBS407 5 long-term survivors. Transplant Following Marqibo Treatment Of the 65 subjects in HBS-407, 12 (18.5%) were treated with HSCT after being treated with Marqibo HSCT, 5 of whom did so after achieving CR+CRi. Another 3 subjects were able to achieve stable disease, allowing them to undergo a stem cell transplant. The remaining 3 subjects were able to receive a transplant even after disease progression. Median overall survival was 8 months for the subjects who achieved CR+CRi and received subsequent HSCT. This compares with overall survival rates of 66.7% (95% CI: 28.9, 100.0) Page 66

67 at 7 months and 16.7% (95% CI: 0.0, 46.5) at 10 months for the 6 subjects who achieved CR+CRi and did not receive subsequent HSCT therapy Subgroup Analyses of Efficacy Table 13 shows the complete response rates and 95% CIs by patient subgroup. The largest difference in complete response rates (CR+CRi) was observed for subjects who had an extramedullary disease (40.0%) compared with those who did not (12.7%) but there was significant overlap in the CIs. The rest of the analyses were generally consistent by patient subgroup although there were limited numbers of patients in many groups. Page 67

68 Table 13. Characteristic (ITT Population) Gender Female (N = 32) Male (N = 33) Age at Study Entry years (N = 29) years (N = 28) 60 years (N = 8) ECOG Status ECOG 0, 1 (N = 50) ECOG 2,3 (N = 15) Cytogenetic Abnormalities Intermediate (N = 23) Unfavorable (N = 33) ALL Type Precursor B-Lymphoblastic Leukemia (N = 55) Precursor T-Lymphoblastic Leukemia (N = 10) Extramedullary Disease Yes (N = 10) No (N = 55) Baseline Platelet Count > /L (N = 26) /L (N = 39) Prior HSCT Yes (N = 31) No (N = 34) First Remission Duration > 36 months (N = 8) 36 months (N = 57) Complete Response by Baseline Demographic and Disease Characteristics or Prior Therapy Study HBS407 a 95% CI generated using the binomial distribution (Clopper-Pearson). Source: CR+CRi (%) [Exact 95% CI] a N = [ ] 18.2 [ ] 27.6 [ ] 7.1 [ ] 12.5 [ ] 22.0 [ ] 0.0 [ ] 21.7 [ ] 12.1 [ ] 16.4 [ ] 20.0 [ ] 40.0 [ ] 12.7 [ ] 30.8 [ ] 7.7 [ ] 22.6 [ ] 11.8 [ ] 25.0 [ ] 15.8 [ ] 5.5 Study VSLI Study Design Study VSLI-06 was a Phase 1/2, multicenter, open-label study of Marqibo combined with pulse dexamethasone. VSLI-06 was designed to be conducted in 2 phases. The phase 1 portion of the study was designed to define the MTD of Marqibo (details provided in Page 68

69 Section 5.2). The phase 2 portion of the study had a Simon 2-stage design and was to determine the efficacy of the chosen Marqibo MTD in a larger cohort of subjects. It was decided not to continue with the phase 2 portion of Study VSLI-06, but instead to design and initiate the Phase 2 Study HBS407. Efficacy data from the Phase 1 portion only of Study VSLI-06 are presented below Clinical Efficacy Demographic and Other Baseline Characteristics Of 36 subjects in the ITT population, the majority was male (24, 66.7%). Subjects were of Caucasian (18 [50.0%] subjects), Hispanic (14 [38.9%] subjects), and Black (4 [11.1%] subjects) race/ethnicity, with an overall mean age (± standard deviation) of 36.3 years (±13.83). At baseline, their mean weight was 87.4 kg (± 26.18). A total of 34 subjects had an original diagnosis of ALL and 2 subjects were diagnosed with Burkitt s-like lymphoma. One subject with ALL was Philadelphia chromosome positive (Ph+) and refractory to imatinib therapy, while the remaining 35 subjects were Ph-. Mean time interval since original diagnosis was 1.9 years (± 1.81). Three subjects (8.3%) had bone marrow involvement, with a mean blast percent of 67.6% (± 24.36). ECOG performance status at baseline was at level 2 or 3 for 7 (19.4%) subjects. All subjects had received at least 1 line of anti-leukemia therapy prior to enrollment, 15 (41.7%) subjects had received 2 lines of therapy, and 8 subjects (22.2%) had received 3 lines of therapy. First-line treatment was reported to include systemic chemotherapy in all subjects, radiation in 7 subjects, and HSCT in 3 subjects. First-line treatment resulted in a CR in 28 subjects, HI in 1 subject, and NR in 6 subjects. The mean duration of response to first-line treatment was 17.8 months (± 14.5 months). Of the 23 subjects who had received second-line treatment, 22 received chemotherapy, 3 received radiation, 2 had received HSCT, and 1 underwent a surgical intervention. Of the 8 subjects who had received third-line treatment, all received chemotherapy and 1 each received radiation and underwent HSCT. A total of 6 (16.7%) subjects underwent at least one HSCT prior to enrollment in Study VSLI-06. All subjects were previously treated with at least 1 dose of standard vincristine. The majority of subjects (26, 72.2%) had a prior history of neuropathy or other neurological condition. Paraesthesia, hypoesthesia, asthenia, pain, constipation, and hyporeflexia were reported in > 15% of subjects. Page 69

70 Dosing Of the 36 enrolled subjects, 18 received at least 1 dose of Marqibo 2.25 mg/m 2. Subjects in the 2.25 mg/m 2 cohort received a median of 4 doses of Marqibo (range 2-8), with a median individual dose size of 4.67 mg (range mg). The median cumulative Marqibo exposure in the 2.25 mg/m 2 cohort was 19.2 mg (range mg). Six subjects (1 in the 1.5 mg/m 2 dose cohort and 5 in the 2.25 mg/m 2 dose cohort) experienced missed, delayed, and/or reduced doses of Marqibo in Study VSLI-06. One subject in the 1.5 mg/m 2 dose cohort had a reduced dose due to peripheral neuropathy of Grade 2 severity. In the 2.25 mg/m 2 treatment group, 1 subject missed 5 doses (due to C. difficle colitis, abdominal pain, and diarrhea), 1 subject had a reduced dose (due to abdominal pain), 2 subjects had a reduced/delayed dose due to constipation of Grade 3 severity, and 1 subject had 2 delayed doses (one due to constipation and the other due to altered mental status). No subject required more than 1 dose reduction Efficacy Results Table 14 shows tumor response by dose cohort in the ITT population of Study VSLI-06. In addition to the MTD cohort, responses, including CR, were also observed at the 1.5, 1.825, and 2.4 mg/m 2 dose levels. As a reminder, VSLI-06 was designed to identify the maximum tolerated dose and it was not powered to examine efficacy by dose. Of the 18 subjects in the 2.25 mg/m 2 dose cohort, 4 subjects (22.2%, 95% CI: 6.4%, 47.6%) experienced an OR (i.e., CR+PR): 3 subjects (16.7%, 95% CI: 3.6%, 41.4%) experienced a CR, and 1 subject (5.6%, 95% CI: 0.1%, 27.3%) experienced a PR. Hematologic improvement was seen in 2 additional subjects (11.1%, 95% CI: 1.4%, 34.7%). Ten subjects (6 NR and 4 PD) did not experience a measurable efficacy response to Marqibo 2.25 mg/m 2. Tumor assessments were not completed in 2 subjects who died before completing a full course of treatment. Excluding these 2 subjects brings the CR incidence in the 2.25 mg/m 2 treatment group to 18.8% and OR to 25%. Page 70

71 Table 14. Principal Investigators Assessment of Tumor Response: Study VSLI-06 (ITT Population) Best Response Assessment Marqibo 1.5 mg/m 2 (N = 5) Marqibo mg/m 2 (N = 3) Marqibo 2.0 mg/m 2 (N = 3) Marqibo 2.25 mg/m 2 (N = 18) Marqibo 2.4 mg/m 2 (N = 7) Marqibo Total (N = 36) Overall Response CR+PR [n (%)] 2 (40.0) 1 (33.3) 0 (0.0) 4 (22.2) 1 (14.3) 8 (22.2) Exact 95% CI a (Clopper-Pearson) ( ) ( ) ( ) ( ) ( ) ( ) Complete Response (CR) [n (%)] 2 (40.0) 1 (33.3) 0 (0.0) 3 (16.7) 1 (14.3) 7 (19.4) Exact 95% CI a (Clopper-Pearson) ( ) ( ) ( ) ( ) ( ) ( ) Partial Response (PR) [n (%)] 0 (0.0) 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (2.8) Exact 95% CI a (Clopper-Pearson) ( ) ( ) ( ) ( ) ( ) ( ) Hematologic Improvement (HI) [n (%)] 0 (0.0) 0 (0.0) 1 (33.3) 2 (11.1) 1 (14.3) 4 (11.1) Exact 95% CI a (Clopper-Pearson) ( ) ( ) ( ) ( ) ( ) ( ) No Response (NR) [n (%)] 2 (40.0) 2 (66.7) 1 (33.3) 6 (33.3) 2 (28.6) 13 (36.1) Exact 95% CI a (Clopper-Pearson) ( ) ( ) ( ) ( ) ( ) ( ) Progressive Disease (PD) [n (%)] 1 (20.0) 0 (0.0) 1 (33.3) 4 (22.2) 3 (42.9) 9 (25.0) Exact 95% CI a (Clopper-Pearson) ( ) ( ) ( ) ( ) ( ) ( ) Not Done (ND) [n (%)] 0 (0.0) 0 (0.0) 0 (0.0) 2 (11.1) 0 (0.0) 2 (5.6) Exact 95% CI a (Clopper-Pearson) ( ) ( ) ( ) ( ) ( ) ( ) CI = confidence interval. a Exact 95% confidence interval generated using the binomial distribution. Source: VSLI-06 CSR, Table Page 71

72 The post-hoc IRRC assessment agreed with the PI assessments of response for all subjects in the MTD cohort. Of 8 subjects who received Marqibo 2.25 mg/m 2 as second-line therapy, 2 (25.0%) achieved a CR; of 8 subjects who received Marqibo 2.25 mg/m 2 as third-line therapy, 2 (25.0%) achieved a CR, 1 achieved PR, and 2 had hematologic improvement; neither of 2 subjects who received Marqibo 2.25 mg/m 2 as fourth-line or greater therapy achieved a CR (Thomas et al 2009). 5.6 Historical Salvage Response Rates Literature searches were conducted to identify potentially relevant data on response rates in the advanced, relapsed and/or refractory adult Ph- ALL setting (refer to Appendix C). The literature search identified 4 potential studies of interest (Table 15). Table 15 Studies Identified with Response Rates in Adult ALL Study Population Treatment Response Kantarjian et al. (2003) N = 8 Clofarabine 13% CR/CRi Cohen et al. (2008) T-cell N = 28 Nelarabine 21% CR/CR* Median OS 4.8m Advani et al. (2010) N = 37 Clofarabine + Cytarabine 16% CR/CRi Median OS 3m O Brien et al. (2008) 2 nd Salvage N = 288 Retrospective review of a variety of therapies 18% CR/CRi Median OS 3m Kantarjian H, Gandhi V, Cortes J, Verstovsek S, Du M, Garcia-Manero G, Giles F, Faderl S, O'Brien S, Jeha S, Davis J, Shaked Z, Craig A, Keating M, Plunkett W, Freireich EJ. Phase 2 clinical and pharmacologic study of clofarabine in patients with refractory or relapsed acute leukemia. Blood Oct 1;102(7): This single-center MD Anderson Cancer Center study evaluated 62 patients with hematologic malignancies including 12 patients with relapsed ALL. The study treatment consisted of single-agent clofarabine 40 mg/m 2 /day on days 1-5 of a 3 to 6 week cycle. Four of 12 (33%) ALL patients were in a first relapse and in need of a second line therapy; 8 of 12 (67%) Page 72

73 required a third or greater line of therapy. There was one CR of 4 months duration from second-line clofarabine in a 31 year-old man with Philadelphia chromosome (Ph) positive ALL in first relapse. There was one CRp of 1-month duration from fourth-line clofarabine in a 23 year-old man with Ph-negative ALL in second relapse that had received a prior transplant. Thus, the CR+CRp rate in patients that might have met the HBS407 eligibility criteria was 12.5% (1 of 8). Cohen MH, Johnson JR, Massie T, Sridhara R, McGuinn WD Jr, Abraham S, Booth BP, Goheer MA, Morse D, Chen XH, Chidambaram N, Kenna L, Gobburu JV, Justice R, Pazdur R. Approval summary: nelarabine for the treatment of T-cell lymphoblastic leukemia/lymphoma. Clin Cancer Res Sep 15;12(18): This paper describes the trial data that supported the accelerated approval of nelarabine in both pediatric and adult ALL indications. The data of interest in adult T-cell lineage ALL and lymphoblastic lymphoma is based on a study conducted by CALGB as an intergroup trial along with SWOG. Nelarabine was administered as 1500 mg/m 2 /day on days 1, 3, and 5 of a 21-day cycle. Patients had to be refractory to at least one induction regimen or in a first relapse following achievement of a CR. The mean age was 30 years with a range of 16 to 65 years. The majority (82%) of patients were male, 61% had ALL in contrast to lymphoblastic lymphoma, and 14% had had a prior transplant. In the efficacy population of 28 adults, there were 5 CR and 1 CR*. CR* represents a morphologic CR lacking blood count and/or bone marrow recovery. The CR rate was 18% [95% CI 6, 37]. The CR+CR* rate was 21% [95% CI 8, 41]. One of the 6 responders went to a subsequent transplant with a median response duration in the remaining 5 patients of 19 weeks. Advani AS, Gundacker HM, Sala-Torra O, Radich JP, Lai R, Slovak ML, Lancet JE, Coutre SE, Stuart RK, Mims MP, Stiff PJ, Appelbaum FR. Southwest Oncology Group Study S0530: a phase 2 trial of clofarabine and cytarabine for relapsed or refractory acute lymphocytic leukaemia. Br J Haematol Dec;151(5): This multi-center SWOG study enrolled 37 patients and assessed 36 evaluable patients (median age 41 years, range: 20 to 68 years) with relapsed or refractory ALL who were treated with a combination regimen consisting of clofarabine 40 mg/m 2 /day and cytarabine 1 g/m 2 /day both delivered on days 1-5 of cycle 1 and days 1-4 of subsequent cycles. Twenty of 36 (56%) patients were in a first relapse in need of second-line therapy, 7 of 36 (19%) Page 73

74 patients were reported to be in a second or greater relapse, and 9 of 36 (25%) patients were in first relapse and refractory to a re-induction attempt. Twenty-nine of 36 (81%) patients had B-cell lineage ALL with the remainder having T-cell lineage ALL. Two of 36 (6%) had undergone a prior transplant. The median time from original ALL diagnosis to study registration was 14 months (range: 1 to 52 months). Response assessment was based only on local bone marrow examination and not central review. Population CR+CRi % [95% CI] Total (N=36) 17 [6, 33] First relapse/2 nd line (N=20) 15 [3, 38] First relapse/refractory/3 rd line (N=9)* 33 [7, 70] Second relapse (N=7)* 0 [0, 41] * = might have been eligible for HBS407 Median overall survival in the 36 patients was 3 months. Eight patients went on to undergo a transplant. Grade 3 infections were reported in 64% of patients. The CR+CRi rate in the 3 of 16 patients who might have met HBS407 eligibility criteria was 18.8% with 95% CI of 4% to 45.7% which does not exclude 7.5%. In short, there were no applicable data for historical comparison collected in a randomized, controlled study in the advanced, relapsed and/or refractory adult Ph- ALL setting. One retrospective study of second-line treatment patients (Thomas et al 1999) and one retrospective study of third-line treatment patients (O Brien et al 2008) at MDACC were identified and used to help interpret the findings from Studies HBS407 and VSLI-06. Of note, the O Brien review was published after the initiation of Study HBS407, therefore the comparison with O Brien was not pre-specified in the Study HBS407 Statistical Analysis Plan. The criteria that the authors used to define response and a summary of the patients treated at MDACC are presented in Appendix C. Page 74

75 5.6.1 Third-Line Therapy of ALL While the MDACC data published by O Brien (2008) provide the best historical comparison data in adults with relapsed/refractory ALL, there are noteworthy, major differences between the data sources: Line of treatment third line in MDACC vs. third, fourth, or fifth in HBS407 Transplant allowed immediately in MDACC vs. subjects ineligible in HBS407 Adjudication at the site for MDACC vs. central review in HBS407 All HBS407 subjects and most from MDACC were treated during an era of contemporary cancer supportive care (e.g., regular use of hematopoietic growth factors and prophylactic antimicrobials). Of 288 MDACC patients, 70 were treated with a single agent, and 218, with multiple agents. Of the 70 patients treated with a single agent, 14 were treated with Marqibo or had PH+ ALL. Table 16 shows a comparison of the various groups in the O Brien study based upon number of adverse factors. The 56 patient single-agent group was most similar to the HBS407 subjects based on distribution of risk factors for poor survival (e.g., 52% of MDACC patients and 59% of HBS407 subjects had 3 to 4 factors that adversely affect survival. In comparison, MDACC patients receiving multi-agent salvage therapy had fewer such risk factors (and better prognosis). Page 75

76 Table 16. Percent of Patients by Number of Risk Factors that Adversely Affect Survival: MDACC vs. HBS407 No. of Survival Adverse Factors a All Therapies (N = 288) MDACC Experience Multi-Agent Treatment b (n = 218) Single Agent Treatment c (n = 56) HBS407 (N = 65) % 27% 16% 12% 2 34% 35% 32% 29% % 39% 52% 59% a. Adverse factors = first CR <36 months duration, platelet count 50K, marrow blasts >50%, and albumin <3.0. b. VAD (vincristine, doxorubicin, and dexamethasone) or hyper-cvad (hyper-fractionated cyclophosphamide and VAD alternating with methotrexate and cytarabine) (n=61, 21%); cytarabine combinations (n=54, 19%); methotrexate-asparaginase combinations (n=52, 18%); allogeneic HSCT (n=22, 8%); and, other combinations (n=29, 10%). c. 14 patients with Marqibo exposure or who were Ph+ were excluded Source: O Brien et al. 2008; Deitcher et al Table 17 provides additional comparative data on the 56 single agent cohort from O Brien with HBS407. Though comparable in the number of survival adverse factors as shown in Table 16, the HBS407 study population was significantly more likely to have 3 or more prior lines of treatment. No subject in the O Brien study and 31 (47.7%) in HBS407 had previously received HSCT. Page 76

77 Table 17. Demographic and Other Characteristics ITT Subjects in Study HBS407 and 56 Patient O Brien Cohort HBS407-ITT N = 65 O Brien Study N = 56 Age (years), Median (range) 31 (19-83) 41 (17-73) Diagnosis, N (%) ALL Lymphoblastic lymphoma Acute undifferentiated leukemia 65 (100) (94.6) 2 (3.6) 1 (1.8) Unfavorable cytogenetics, N (%) a 33 (50.7) 5 (8.9) Baseline platelet count /L), N (%) a 36 (55.4) 34 (60.7) Prior lines of therapy, N (%) Two Three Four or greater 32 (49.2) 24 (36.9) 9 (13.8) Prior HSCT, N (%) 31 (47.7%) 0 Prognostic Category, N (%) a a Favorable Intermediate Unfavorable 2 (3.1) 21 (32.3) 42 (64.6) 56 (100) (3.6) 21 (37.5) 33 (58.9) All missing data has been imputed using the most conservative definition showing similar bias against HBS407. Source: O Brien et al 2008; Module 5, HBS407 CSR, Table , Table , Table , Table , and Table ; and ISE Tables, Ad Hoc Tables 9004 through Table 18 shows the treatment outcomes observed with Marqibo 2.25 mg/m 2 in HBS-407 and those with single- and multi-agent therapy in the MDACC experience. The complete response rate in Study HBS407 as a result of weekly, single-agent Marqibo 2.25 mg/m 2 was 20.0%, about 5.6-fold greater than was observed in the MDACC single-agent subgroup (N=56, 3.6%) and comparable to that observed among the MDACC patients treated with multi-agent therapy (20.9%). As previously noted, 12 (18.5%) of the 65 subjects in HBS407 had a remission duration sufficiently long following Marqibo treatment to facilitate a subsequent, and potentially curative HSCT, and 5 (7.7%) subjects had post-marqibo survival greater than 1 year. The early plus induction (30-day) mortality rate with singleagent Marqibo 2.25 mg/m 2 (12.3%) was about half that for single-agent (30.4%) and multiagent therapies (22%) used at MDACC. Likewise, median overall survival was longer with Marqibo monotherapy in HBS407 (4.6 months) than was observed with single- and multiagent therapy at MDACC (2.1 months and 3.3 months, respectively). Page 77

78 Table 18. Results of Single- and Multi-Agent Therapy for Advanced Adult ALL MDACC Experience* Outcome Complete response rate, n (%) [95% CI] All Therapies (N = 288) 53 (18.4%) [14.0%, 23.4%] Multi-Agent Treatment a (n = 196) 41 (20.9%) [15.4%, 27.4%] Single Agent Treatment b (n = 56) 2 (3.6%) [0.4%, 12.4%] HBS407 (N = 65) 13 (20.0%) [11.1% %] Complete response duration in responders, median 23 weeks [5,852 b ] 26 weeks [5, 852 b ] 9.5 weeks [5, 14 b ] 23 weeks [5, 66+] Overall survival, median Early and Induction Death n (%) [95% CI] * Clopper-Pearson methodology 3.2 months [0, 231 d ] 66 (22.9%) [18.1%, 28.3%] 3.3 months [0, 231 d ] 43 (21.9%) [16.3%, 28.4%] 1.8 months [0, 25.7 d ] 17 (30.4%) [18.7%, 44.1%] 4.6 months [0.5, 22+] 8 (12.3%) c [5.5%, 22.8%] a. Excludes patients who underwent immediate transplant (n = 22) b Excludes patients with Ph+ ALL and patients who received Marqibo as third line therapy c 30 day mortality d Unconfirmed time of deaths (patients considered in CR until proven otherwise) Source (Talon HBS407): 2.7.3, Appendix E Adapted from O Brien et al Thus, based upon a conservative comparison with published literature (O Brien et al 2008), Marqibo provides greater clinical benefit to the expected experience with a single agent and has the potential to advance the care of all patients with Ph- Adult ALL Second-line Therapy of ALL To interpret the second-line therapy response observed in Study VSLI-06, the response rate with Marqibo 2.25 mg/m 2 was compared to the findings published by Thomas and MDACC co-workers, the largest evidence base for treatment results and prognosis following secondline treatment of patients with refractory or first relapsed adult ALL (Thomas et al 1999). In the historical comparison group, 2 of 25 patients who received single-agent, second-line therapy achieved remission (8%; 95% CI: 1.0, 26.0) (Thomas et al 1999) (Table 19). The 30- day mortality rate with single-agent, second-line therapy was 20% (95% CI: 6.8, 40.7). Among the 289 patients treated with multi-agent, second-line therapy, 95 (32.9%) achieved remission and 61 (21%) patients died during second-line treatment. Page 78

79 Table 19. Results of Single-Agent Second-Line Therapy for Adult ALL Characteristic Outcome CR rate, n/n (%) [95% CI] 2/25 (8%) [1.0%, 26.0%] CR duration in responders, median 21 weeks Overall survival, median 10 weeks 30-day mortality, n/n (%) [95% CI] 5/25 (20%) [6.8%, 40.7%] Adapted from Thomas et al The complete response rate of 25.0% (2/8) for second-line therapy with Marqibo 2.25 mg/m 2 in Study VSLI-06 (Thomas 2009) exceeds the historical rate of 8.0% (Thomas et al 1999). This combined with a higher complete response rate of 25.0% (2/8) for third-line therapy with Marqibo 2.25 mg/m 2 in Study VSLI-06 (Thomas 2009) versus the historical rate of 3.6% (O Brien et al 2008), suggests efficacy with Marqibo in adult Ph- ALL. Page 79

80 6. Clinical Safety 6.1 Description of the Safety Populations and Extent of Exposure Table 33 (Supplemental Table in Appendix E) summarizes study characteristics of the 17 studies that have been conducted with Marqibo in ALL and other types of hematological malignancy, melanoma, small cell lung cancer, colorectal cancer, and pancreatic cancer. Across the 17 studies, 774 subjects were enrolled and treated with doses ranging from 1.0 to 2.8 mg/m 2 administered up to once a week for as many as 18 cycles. The primary safety population consisted of the experience from Studies HBS407 and VLS-06, which enrolled 101 subjects with relapsed or refractory ALL. All 65 subjects in Study HBS407 and 11 subjects in VSLI-06 were in their second or greater relapse or had failed two or more lines of anti-leukemia chemotherapy. The remaining subjects in the other studies form the secondary safety population. Those subjects not included in the primary safety population were the 673 subjects largely from relapsed aggressive Non-Hodgkins lymphoma studies conducted at 2.0 mg/m 2 administered every two weeks as well as Phase 2 studies in solid tumors and Phase 1/2 dose identification studies in pediatric and adolescent populations. HBS408 remains ongoing and has enrolled 47 subjects with metastatic malignant uveal melanoma. The HBS408 protocol prespecified collection of ECG data timed to Marqibo administration for an analysis of QT interval data. Table 20 summarizes the demographic characteristics of the 101 Marqibo -exposed subjects in Studies HBS407 and VLSI-06. The majority (74; 73.3%) was White/Caucasian, with slightly more males (56.4%) than females and mean age being 36.3 years (range: years). Most subjects (89.1%) were less than 60 years of age. Page 80

81 Table 20. Demographic Characteristics (Study HBS407 and Study VSLI-06, N=101) Variable at Baseline Gender, n (%) mg//m mg//m mg//m 2 Overall VSLI-06 (N=11) VSLI-06 (N=7) VSLI-06 (N=18) HBS407 (N=65) Total (N=83) Total (N=101) Female 3 (27.3) 4 (57.1) 5 (27.8) 32 (49.2) 37 (44.6) 44 (43.6) Male 8 (72.7) 3 (42.9) 13 (72.2) 33 (50.8) 46 (55.4) 57 (56.4) Race, n (%) White or Caucasian 6 (54.5) 3 (42.9) 9 (50.0) 56 (86.2) 65 (78.3) 74 (73.3) Black or African American 1 (9.1) 1 (14.3) 2 (11.1) 4 (6.2) 6 (7.2) 8 (7.9) Asian 0 (0.0) 0 (0.0) 0 (0.0) 2 (3.1) 2 (2.4) 2 (2.0) Hispanic 4 (36.4) 3 (42.9) 7 (38.9) N/A 7 (8.4) 14 (13.9) Other 0 (0.0) 0 (0.0) 0 (0.0) 3 (4.6) 3 (3.6) 3 (3.0) Age (years) n Mean (std) 35.5 (12.52) 36.4 (15.59) 36.7 (14.68) 36.4 (16.40) 36.4 (15.96) 36.3 (15.46) Median Q1, Q3 22, 43 24, 49 24, 55 25, 43 24, 43 24, 43 Min, Max 21, 58 18, 60 23, 62 19, 83 19, 83 18, 83 BSA (m 2 ) n Mean (std) 2.07 (0.443) 2.08 (0.391) 1.99 (0.270) 1.90 (0.259) 1.92 (0.263) 1.94 (0.299) Median Q1, Q3 1.7, , , , , , 2.2 Min, Max 1.5, , , , , , 2.9 Source: ISS Table 1.4. Page 81

82 All 101 subjects in Studies HBS407 and VSLI-06 had a primary diagnosis of ALL, with 55 subjects (54.5%) having precursor B-lymphoblastic leukemia, 34 (33.7%) subjects having ALL with no designated lineage, 10 (9.9%) subjects having precursor T-lymphoblastic leukemia, and 2 (2.0%) subjects having Burkitt s like lymphoma (Source: ISS Tables through 1.5.3). StudyVSLI-06 primarily enrolled subjects with ALL with no designated lineage, whereas Study HBS407 enrolled subjects designated as precursor B and T- lymphoblastic leukemia, exclusively. Of the 101 subjects, 63.4% had not had a HSCT (Source: ISS Tables and 1.6.2). The most frequently reported medical conditions at baseline included anemia (42.6%), thrombocytopenia (39.6%), fatigue (37.6%), infection (29.7%), drug hypersensitivity (27.7%), depression (22.8%), hypertension (22.8%), headache (18.8%), insomnia (18.8%), tachycardia (18.8%), and gastroesophageal reflux disease (17.8%) (Source: ISS Table 1.7.5). Of the 83 subjects treated with Marqibo 2.25 mg/m 2, 80% had evidence of preexisting neuropathy at baseline, with 32.5% reporting pain, 27.7% reporting asthenia, 24.1% having areflexia, 24.1% reporting hypoesthesia, 24.1% having hyporeflexia, and 20.5% reporting paresthesia (Source: ISS Table 1.7.1). Section presents findings from a detailed review of preexisting (baseline) and treatment-emergent neuropathy. Table 21 summarizes the range of Marqibo doses for the 101 exposed subjects in Studies HBS407 and VLSI-06. Of the 101 subjects, 83 were treated with the proposed dose of 2.25 mg/m 2. Table 21. Subjects by Marqibo Dose (All Screened Subjects) Population mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) VSLI-06 (N=7) VSLI-06 (N=18) HBS407 (N=68) Total (N=86) Total (N=104) Subjects Screened, n Subjects Not Treated, n (%) a 0 (0.0) 0 (0.0) 0 (0.0) 3 (4.4) 3 (3.5) 3 (2.9) Subjects Treated, n (%) a 11 (100.0) 7 (100.0) 18 (100.0) 65 (95.6) 83 (96.5) 101 (97.1) Safety Population, n (%) a,b 11 (100.0) 7 (100.0) 18 (100.0) 65 (95.6) 83 (96.5) 101 (97.1) a. Percent of all Screened subjects. b. Also to as the ALL Registration Studies Population. Source: ISS Table 1.1 Among these 83 subjects dosed at 2.25 mg/m 2 in Studies HBS407 and VSLI-06, the mean and median duration of Marqibo therapy was 4.0 and 6.1 weeks, respectively (Source: ISS Table 3.1.1). The mean number of Marqibo infusions was 5.3 (median: 4.0), with the Page 82

83 number of infusions ranging from 1 to 18; 44.6%, 13.3%, and 6.0% continued treatment in courses 2, 3, and 4, respectively. The mean individual dose was 4.2 mg (range 3.1, 5.6 mg), and mean cumulative exposure was 22.2 mg (range, 3.5, 70.1 mg). Of the 83 subjects treated at 2.25 mg/m 2, 44 (53%) received the intended dose on the intended schedule, 17 (20.5%) missed doses, 18 (21.7%) had reduced doses, and 4 (4.8%) had delayed doses (Source: ISS Table 3.1.2). Marqibo was discontinued in all 101 subjects who received Marqibo in Studies HBS407 and VSLI-06 (Source: ISS Table 1.2). The study protocols stipulated that study treatment be discontinued should there be disease progression, which was the most common reason for study treatment discontinuation (41.6%). The other common reasons for study treatment discontinuation were AEs (some of which described events consistent with disease progression, although not specifically defined as disease progression) (28.7%) and subject eligible for other treatment (6.9%). Among the 83 subjects who received the 2.25 mg/m 2 dose of Marqibo, the most common reasons (>5% of subjects) for discontinuation of treatment were disease progression (39.8%), AEs (some consistent with disease progression) (30.1%), at the request of the investigator (7.2%), discontinued because of planned HSCT (6%), and 6.0% subject withdrew their consent (6%). Adverse events leading to treatment discontinuation are further detailed in Section Adverse Events in Studies HBS407 and VSLI All Adverse Events Table 22 shows the overall AE experience in Studies HBS407 and VSLI-06. To provide context, after being enrolled into a Marqibo study, more than half of the subjects (56%) reported AEs prior to receiving the first dose of Marqibo, which is consistent with a very ill, near end-stage leukemia population. All subjects reported at least 1 treatment-emergent AE during study participation, with the majority (88.1%) having an event classified by the investigator as related to treatment. Page 83

84 Table 22. Overall Summary of Adverse Events (Study HBS407 and Study VSLI-06, N=101) Adverse Event Category mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) Any Adverse Event 11 (100.0) 7 (100.0) 18 (100.0) 65 (100.0) 83 (100.0) 101 (100.0) Any Treatment-Related Adverse Event 11 (100.0) 7 (100.0) 18 (100.0) 53 (81.5) 71 (85.5) 89 (88.1) Any Grade 3 Adverse Event 11 (100.0) 7 (100.0) 18 (100.0) 62 (95.4) 80 (96.4) 98 (97.0) Any Grade 3 Treatment-Related Adverse Event 6 (54.5) 5 (71.4) 13 (72.2) 40 (61.5) 53 (63.9) 64 (63.4) Any Adverse Event with Outcome of Death 0 (0.0) 0 (0.0) 3 (16.7) 21 (32.3) 24 (28.9) 24 (23.8) Any Serious Adverse Event 9 (81.8) 7 (100.0) 17 (94.4) 46 (70.8) 63 (75.9) 79 (78.2) Any Treatment-Related Serious Adverse Event 2 (18.2) 4 (57.1) 6 (33.3) 21 (32.3) 27 (32.5) 33 (32.7) Any Adverse Event Leading to Discontinuation 2 (18.2) 3 (42.9) 1 (5.6) 22 (33.8) 23 (27.7) 28 (27.7) Any Treatment-Related Adverse Event Leading to Discontinuation 2 (18.2) 3 (42.9) 1 (5.6) 16 (24.6) 17 (20.5) 22 (21.8) Note: Only treatment-emergent adverse events are summarized. For each category, subjects are included only once, even if they experienced multiple events in that category. Source: ISS Table Page 84

85 The most frequently reported AEs were constipation (57.4%), nausea (51.5%), pyrexia (42.6%), fatigue (40.6%), peripheral neuropathy (38.6%), febrile neutropenia (37.6%), diarrhea (36.6%), anemia (33.7%), decreased appetite (32.7%), and insomnia (31.7%) (Source: ISS Table ). In general, the pattern of AEs was consistent with ALL or vincristine exposure. There was little difference in AE rates by Marqibo dose. Table 23 shows the most commonly reported AEs of Common Terminology Criteria for Adverse Events (CTCAE) Grade 3. Overall, 97.0% of subjects reported AEs of Grade 3 severity (most due to disease progression). The most common AEs of Grade 3 were febrile neutropenia (31.7%), neutropenia (22.8%), anemia (21.8%), thrombocytopenia (21.8%), pyrexia (14.9%), and peripheral neuropathy (10.9%). Most CTCAE Grade 3 AEs were related to the progression of the baseline leukemia disease. The qualitative pattern of the most frequent Grade 3 AEs was comparable across dose levels and mostly involved sequelae of bone marrow suppression in the setting of relapsed ALL. Page 85

86 Table 23. Adverse Events Grade >= 3 Occurring in >= 5% of All Subjects by System Organ Class and Preferred Term (Study HBS407 and Study VSLI-06, N=101) System Organ Class (> 5% overall) Preferred Term (> 5% overall) mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) Any Grade 3 Adverse Event 11 (100.0) 7 (100.0) 18 (100.0) 62 (95.4) 80 (96.4) 98 (97.0) BLOOD AND LYMPHATIC SYSTEM DISORDERS 9 (81.8) 7 (100.0) 12 (66.7) 35 (53.8) 47 (56.6) 63 (62.4) Febrile Neutropenia 5 (45.5) 2 (28.6) 5 (27.8) 20 (30.8) 25 (30.1) 32 (31.7) Neutropenia 6 (54.5) 2 (28.6) 4 (22.2) 11 (16.9) 15 (18.1) 23 (22.8) Anaemia 2 (18.2) 6 (85.7) 6 (33.3) 8 (12.3) 14 (16.9) 22 (21.8) Thrombocytopenia 2 (18.2) 6 (85.7) 3 (16.7) 11 (16.9) 14 (16.9) 22 (21.8) INFECTIONS AND INFESTATIONS 5 (45.5) 4 (57.1) 10 (55.6) 23 (35.4) 33 (39.8) 42 (41.6) Bacteraemia 5 (45.5) 2 (28.6) 1 (5.6) 1 (1.5) 2 (2.4) 9 (8.9) Pneumonia 0 (0.0) 1 (14.3) 0 (0.0) 7 (10.8) 7 (8.4) 8 (7.9) Septic Shock 0 (0.0) 0 (0.0) 1 (5.6) 4 (6.2) 5 (6.0) 5 (5.0) Staphylococcal Bacteremia 0 (0.0) 0 (0.0) 4 (22.2) 1 (1.5) 5 (6.0) 5 (5.0) GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS 2 (18.2) 3 (42.9) 8 (44.4) 23 (35.4) 31 (37.3) 36 (35.6) Pyrexia 1 (9.1) 2 (28.6) 5 (27.8) 7 (10.8) 12 (14.5) 15 (14.9) Fatigue 0 (0.0) 1 (14.3) 3 (16.7) 6 (9.2) 9 (10.8) 10 (9.9) Pain 0 (0.0) 0 (0.0) 1 (5.6) 6 (9.2) 7 (8.4) 7 (6.9) METABOLISM AND NUTRITION DISORDERS 6 (54.5) 3 (42.9) 7 (38.9) 13 (20.0) 20 (24.1) 29 (28.7) Hyperglycaemia 5 (45.5) 1 (14.3) 3 (16.7) 1 (1.5) 4 (4.8) 10 (9.9) Hypokalaemia 2 (18.2) 1 (14.3) 2 (11.1) 2 (3.1) 4 (4.8) 7 (6.9) Dehydration 0 (0.0) 1 (14.3) 2 (11.1) 2 (3.1) 4 (4.8) 5 (5.0) INVESTIGATIONS 2 (18.2) 3 (42.9) 6 (33.3) 14 (21.5) 20 (24.1) 25 (24.8) Page 86

87 Table 23. Adverse Events Grade >= 3 Occurring in >= 5% of All Subjects by System Organ Class and Preferred Term (Study HBS407 and Study VSLI-06, N=101) System Organ Class (> 5% overall) Preferred Term (> 5% overall) mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) Alanine Aminotransferase Increased 1 (9.1) 2 (28.6) 1 (5.6) 3 (4.6) 4 (4.8) 7 (6.9) Aspartate Aminotransferase Increased 0 (0.0) 1 (14.3) 2 (11.1) 4 (6.2) 6 (7.2) 7 (6.9) GASTROINTESTINAL DISORDERS 0 (0.0) 3 (42.9) 8 (44.4) 13 (20.0) 21 (25.3) 24 (23.8) Abdominal Pain 0 (0.0) 2 (28.6) 4 (22.2) 3 (4.6) 7 (8.4) 9 (8.9) NERVOUS SYSTEM DISORDERS 1 (9.1) 2 (28.6) 2 (11.1) 19 (29.2) 21 (25.3) 24 (23.8) Neuropathy Peripheral 1 (9.1) 0 (0.0) 0 (0.0) 10 (15.4) 10 (12.0) 11 (10.9) RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS 2 (18.2) 2 (28.6) 5 (27.8) 12 (18.5) 17 (20.5) 21 (20.8) Hypoxia 1 (1.9) 1 (14.3) 1 (5.6) 2 (3.1) 3 (3.6) 5 (5.0) Respiratory Distress 0 (0.0) 0 (0.0) 2 (11.1) 3 (4.6) 5 (6.0) 5 (5.0) Respiratory Failure 0 (0.0) 1 (14.3) 1 (5.6) 3 (4.6) 4 (4.8) 5 (5.0) NEOPLASMS BENIGN, MALIGNANT AND UNSPECIFIED (INCL CYSTS AND POLYPS) 0 (0.0) 0 (0.0) 0 (0.0) 13 (20.0) 13 (15.7) 13 (12.9) Acute Lymphocytic Leukaemia 0 (0.0) 0 (0.0) 0 (0.0) 9 (13.8) 9 (10.8) 9 (8.9) VASCULAR DISORDERS 1 (9.1) 3 (42.9) 3 (16.7) 5 (7.7) 8 (9.6) 12 (11.9) Hypotension 1 (9.1) 2 (28.6) 3 (16.7) 2 (3.1) 5 (6.0) 8 (7.9) PSYCHIATRIC DISORDERS 0 (0.0) 2 (28.6) 4 (22.2) 5 (7.7) 9 (10.8) 11 (10.9) Mental Status Changes 0 (0.0) 2 (28.6) 1 (5.6) 2 (3.1) 3 (3.6) 5 (5.0) CARDIAC DISORDERS 0 (0.0) 0 (0.0) 3 (16.7) 6 (9.2) 9 (10.8) 9 (8.9) Cardiac Arrest 0 (0.0) 0 (0.0) 2 (11.1) 3 (4.6) 5 (6.0) 5 (5.0) MUSCULOSKELETAL AND CONNECTIVE TISSUE DISORDERS 0 (0.0) 1 (14.3) 1 (5.6) 6 (9.2) 7 (8.4) 8 (7.9) Page 87

88 Table 23. Adverse Events Grade >= 3 Occurring in >= 5% of All Subjects by System Organ Class and Preferred Term (Study HBS407 and Study VSLI-06, N=101) System Organ Class (> 5% overall) Preferred Term (> 5% overall) mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) RENAL AND URINARY DISORDERS 1 (9.1) 1 (14.3) 1 (5.6) 5 (7.7) 6 (7.2) 8 (7.9) Source: ISS Table Page 88

89 6.2.2 AEs Leading to Discontinuation or Dose Reduction Table 24 shows AEs that were associated with study drug discontinuation. Treatmentemergent peripheral neuropathy was the most common AE leading to Marqibo discontinuation. Of the 83 subjects treated with 2.25 mg/m 2, 9 (10.8%) discontinued study drug prematurely due to peripheral neuropathy and associated events, 5 (6.0%) discontinued due to ALL (all associated preferred terms), and 2 (2.4%) discontinued due to tumor necrosis syndrome. Neuropathy AEs are reviewed in more detail in Section Page 89

90 Table 24. Adverse Events Leading to Study Drug Discontinuation (Study HBS407 and Study VSLI-06, N=101) Preferred Term Any Adverse Event Leading to Study Drug Discontinuation mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) 2 (18.2) 3 (42.9) 1 (5.6) 22 (33.8) 23 (27.7) 28 (27.7) Neuropathy Peripheral 2 (18.2) 0 (0.0) 0 (0.0) 7 (10.8) 7 (8.4) 9 (8.9) Peripheral Motor Neuropathy 0 (0.0) 1 (14.3) 0 (0.0) 1 (1.5) 1 (1.2) 2 (2.0) Aspartate Aminotransferase Increased 0 (0.0) 1 (14.3) 0 (0.0) 1 (1.5) 1 (1.2) 2 (2.0) Tumour Lysis Syndrome 0 (0.0) 0 (0.0) 0 (0.0) 2 (3.1) 2 (2.4) 2 (2.0) Cerebral Haemorrhage 0 (0.0) 1 (14.3) 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.0) Decreased Vibratory Sense 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Facial Palsy 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Grand Mal Convulsion 0 (0.0) 1 (14.3) 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.0) Hyporeflexia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Acute Lymphocytic Leukaemia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Acute Lymphocytic Leukaemia Recurrent 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Leukaemia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Leukaemic Infiltration 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Leukaemic Infiltration Brain 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Lymphocytic Leukaemia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Organising Pneumonia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Pulmonary Haemorrhage 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Respiratory Distress 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Constipation 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 1 (1.0) Nausea 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Vomiting 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Page 90

91 Table 24. Adverse Events Leading to Study Drug Discontinuation (Study HBS407 and Study VSLI-06, N=101) Preferred Term mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) Asthenia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Fatigue 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Alanine Aminotransferase Increased 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Musculoskeletal Pain 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Myopathy 1 (9.1) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.0) Pancytopenia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Cardiac Arrest 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Inappropriate Antidiuretic Hormone Secretion 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Hyperbilirubinaemia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Graft Versus Host Disease 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Pneumonia Bacterial 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Mental Status Changes 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Renal Failure 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Source: ISS Table Page 91

92 AEs were also associated with modifications in Marqibo dose. In Study VSLI-06, 3 of the 18 subjects (16.7%) treated with Marqibo 2.25 mg/m 2 required a dose reduction, 4 subjects (22.2%) required a dose delay, and 1 subject (5.6%) required a missed dose. One of the dose reductions was due to abdominal pain and 2 were secondary to constipation. Dose delays for the same AEs accompanied the dose reductions for all three of these subjects. One additional subject had dose delays for constipation and mental status changes, with no dose reductions. One subject skipped doses secondary to C. difficile colitis and neutropenic infection. All the events were reported to have resolved. In study HBS407, 15 of the 65 subjects (23.1%) required at least one dose reduction, 1 (1.5%) subject required a dose delay, and 16 (24.6%) missed a Marqibo dose. Nine dose reductions were due to neuropathy, including 2 due to possible GI autonomic neuropathy and 1 possibly due to SIADH. Missed dose for neuropathy accompanied the neuropathy-related dose reduction for 4 of the subjects. Six subjects had dose reduction for AEs other than neuropathy, including Staphylococcal bacteremia, increased hepatic enzymes, diarrhea, hyponatremia, pain in extremity, and fatigue/weight loss (accompanied by transaminase increases). All the events resolved with the exception of the one event of neuralgia and one event of fatigue. The dosage adjustment algorithms were intended to facilitate continued dosing in order to produce overall responses and minimize the incidence of Grade 3 neuropathy. The median cumulative Marqibo dose in all subjects with a missed, delayed, or reduced dose was 27.4 mg (range mg) compared to a median of 18.6 mg (range mg) in subjects who did not require a missed, delayed, or reduced dose. In Study HBS407, 7 of the 15 (46.7%) subjects with dose reductions achieved CR or CRi. Thus, the dosage modification strategy was able to guide investigators in a way that managed toxicity without reducing cumulative dose or efficacy Death Overall, 67 of the 101 subjects died; 20 during the treatment period and 47 during follow-up. Table 25 lists the cause of these 67 deaths as recorded on either the end-of-treatment or (in study HBS407) the follow-up data collection forms. The most common cause of death was ALL (42 of 101 subjects, 41.6%) and associated disease progression (3 of 101 subjects, 3.0%). Three of 101 subjects (3.0%) died due to complications of a post-study HSCT. The remaining 19 deaths were associated with specific events, some of which also appear to be complications of ALL disease progression. Page 92

93 Among the 83 subjects dosed at 2.25 mg/m 2, 19 (22.9%) died during the treatment period and 47 (56.6%) died during follow-up. The 30-day mortality rate was 13.3% (11/83). The observed mortality rate of 66.3% among these study subjects during the treatment (19.8%) and follow-up (46.5%) periods is consistent with the expected survival in this ALL population. Median survival following relapsed and refractory ALL has been reported to be 12 to 20 weeks (Arranon PI 2009, Advani 2010). The Study HBS407 population represents even more advanced ALL than has been reported previously. As previously mentioned, in the study of third-line therapy for ALL reported by O'Brien et al (2008), 23% of subjects died during the first initial induction cycle (approximately 4 weeks) of third-line therapy (Table 18). The 19.8% on-treatment (i.e., entire duration of salvage therapy, and not just the initial 4 weeks) mortality rate in pooled Studies HBS407 and VSLI-06 was less than in the O'Brien data. The 30-day mortality rate in Study HBS407 was, in fact, 12.3%. Page 93

94 Table 25. Summary of Deaths (Study HBS407 and Study VSLI-06, N=101) Time of Death mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) Deaths During Treatment Period a 1 (9.1) 0 (00.0) 4 (22.2) 15 (23.1) 19 (22.9) 20 (19.8) Deaths During Follow-up b 0 (00.0) 0 (00.0) 2 (11.1) 45 (69.2) 47 (56.6) 47 (46.5) Cause of Death Acute Lymphoblastic Leukemia 0 (0.0) 0 (0.0) 0 (0.0) 42 (64.6) 42 (50.6) 42 (41.6) HSCT Related 0 (0.0) 0 (0.0) 0 (0.0) 3 (4.6) 3 (3.6) 3 (3.0) Disease Progression 1 (9.1) 0 (0.0) 2 (11.1) 0 (0.0) 2 (2.4) 3 (3.0) Other 0 (0.0) 0 (0.0) 4 (22.2) 15 (23.1) 19 (22.9) 19 (18.8) All-Fungal Pneumonia Resp Distress 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 1 (1.0) Cortico-Infarct, Brain 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Infection 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 1 (1.0) Intracerebral Hemorrhage due to CNS Leukemia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Large Cerebellar Hemorrhage 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Liver Failure 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Multi Organ Failure 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 1 (1.0) Multi System Organ Failure 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Other: Pneumonia & Septic Shock Secondary to ALL 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Pneumonia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Pulmonary Hemorrhage 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Respiratory Failure 0 (0.0) 0 (0.0) 0 (0.0) 2 (3.1) 2 (2.4) 2 (2.0) Respiratory Failure Secondary to ALL 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Sepsis and Respiratory Failure 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Septic Shock, Secondary to Neutropenia, - Caused By ALL (Pseudomonas Sepsis) 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Septicemia (E. Coli) 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 1 (1.0) Strep Mitus Leading to Multi-Organ Failure 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Sudden Cardiac Arrest 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) a. Deaths occurred after the first dose infusion date through last dose date +30 days. b. Deaths occurred beyond 30 days after last dose of study drug. This also includes deaths reported during the survival follow-up period for Study HBS407. Source: ISS Tables and Page 94

95 With regard to AEs that resulted in death, 24 subjects (23.8%) experienced 34 serious adverse events (SAEs) that resulted in death (Source: ISS Table ), 5 of whom experienced an SAE(s) that the investigator considered related to study drug, as follows. respiratory distress occurring 2 days from last dose (Subject HBS ): Respiratory failure has been reported as a complication of tumor lysis syndrome. To the extent that Marqibo contributed to the tumor lysis syndrome, it may have by extension also contributed to respiratory distress. graft versus host disease occurring 24 days after last dose (Subject HBS ): the worsening graft-versus-host disease (GVHD) and death due to disease progression appears to be unrelated to Marqibo treatment. cardiac arrest occurring 6 days after last dose (Subject HBS ) (narrative in Appendix D): Cardiotoxicity has been rarely reported in the medical literature as a complication of vincristine therapy. Sudden cardiac arrest in one subject was both unexpected and poorly documented (no ECG or laboratory samples obtained), but may have been associated with the history of acute renal failure, which the subject had at the time of study entry, and was felt to be due to leukemic infiltration of the kidneys. septic shock and cardiac arrest occurring 4 days after last dose (Subject VSLI ; refer to vignette below for details about this event): This case of cardiac arrest occurred in the setting of septic shock and Grade 4 neutropenia. Indirectly, Marqibo may have been contributory to the immunosuppression, which increased the risk for sepsis and septic shock. infection occurring 4 days after last dose (Subject VSLI ). Four cases of cardiac arrest resulted in death, all having pre-existing risk factors (subjects further discussed in Section 6.6.3; subject narratives presented in Appendix D). The PI considered 3 of 4 cardiac arrest events unrelated to Marqibo SAEs Table 26 shows SAEs that occurred in 2 or more subjects across the 101 subjects. The most frequently reported SAEs were febrile neutropenia (23.8%), pyrexia (13.9%), and bacteremia (9.9%). Treatment-emergent peripheral neuropathy occurred in 5.9% of the 101 subjects. Neutropenia and, by extension, febrile neutropenia can be the result of myelosuppression associated with Marqibo in some cases. Tumor lysis syndrome has been associated with a number of cytotoxic chemotherapy agents, including vincristine. Constipation can be multi- Page 95

96 factorial, including a manifestation of vincristine-associated neuropathy as well as a consequence of opiate analgesics frequently administered to this population. In addition to the 4 cases of cardiac arrest mentioned above in Section 6.2.3, there was one SAE of cardiac arrest that did not result in death (narrative in Appendix D). Cardiac arrest is not a rare event in this patient population and there are clinical characteristics to suggest alternative etiologies other than study drug for these events. Page 96

97 Table 26. Serious Adverse Events Occurring in >= 2 Subjects by Preferred Term (Study HBS407 and Study VSLI-06, N=101) MedDRA Preferred Term - n (%) mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) VSLI-06 (N=7) VSLI-06 (N=18) HBS407 (N=65) Total (N=83) Total (N=101) Any Serious Adverse Event 9 (81.8) 7 (100.0) 17 (94.4) 46 (70.8) 63 (75.9) 79 (78.2) Febrile Neutropenia 5 (45.5) 2 (28.6) 5 (27.8) 12 (18.5) 17 (20.5) 24 (23.8) Pyrexia 1 (9.1) 2 (28.6) 7 (38.9) 4 (6.2) 11 (13.3) 14 (13.9) Bacteraemia 5 (45.5) 2 (28.6) 2 (11.1) 1 (1.5) 3 (3.6) 10 (9.9) Acute Lymphocytic Leukaemia 0 (0.0) 0 (0.0) 0 (0.0) 9 (13.8) 9 (10.8) 9 (8.9) Hypotension 1 (9.1) 2 (28.6) 4 (22.2) 2 (3.1) 6 (7.2) 9 (8.9) Pneumonia 1 (9.1) 1 (14.3) 0 (0.0) 5 (7.7) 5 (6.0) 7 (6.9) Neuropathy Peripheral 1 (9.1) 1 (14.3) 0 (0.0) 4 (6.2) 4 (4.8) 6 (5.9) Cardiac Arrest 0 (0.0) 0 (0.0) 2 (11.1) 3 (4.6) 5 (6.0) 5 (5.0) Respiratory Distress 0 (0.0) 0 (0.0) 2 (11.1) 3 (4.6) 5 (6.0) 5 (5.0) Respiratory Failure 0 (0.0) 1 (14.3) 1 (5.6) 3 (4.6) 4 (4.8) 5 (5.0) Abdominal Pain 0 (0.0) 1 (14.3) 3 (16.7) 1 (1.5) 4 (4.8) 5 (5.0) Diarrhoea 0 (0.0) 0 (0.0) 1 (5.6) 3 (4.6) 4 (4.8) 4 (4.0) Neutropenia 0 (0.0) 1 (14.3) 2 (11.1) 1 (1.5) 3 (3.6) 4 (4.0) Dehydration 0 (0.0) 1 (14.3) 2 (11.1) 1 (1.5) 3 (3.6) 4 (4.0) Mental Status Changes 0 (0.0) 1 (14.3) 1 (5.6) 2 (3.1) 3 (3.6) 4 (4.0) Constipation 0 (0.0) 0 (0.0) 1 (5.6) 2 (3.1) 3 (3.6) 3 (3.0) Hypoxia 0 (0.0) 1 (14.3) 1 (5.6) 1 (1.5) 2 (2.4) 3 (3.0) Tumour Lysis Syndrome 0 (0.0) 0 (0.0) 0 (0.0) 3 (4.6) 3 (3.6) 3 (3.0) Thrombocytopenia 0 (0.0) 0 (0.0) 1 (5.6) 2 (3.1) 3 (3.6) 3 (3.0) Pneumonia Fungal 1 (9.1) 0 (0.0) 2 (11.1) 0 (0.0) 2 (2.4) 3 (3.0) Sepsis 0 (0.0) 1 (14.3) 0 (0.0) 2 (3.1) 2 (2.4) 3 (3.0) Septic Shock 0 (0.0) 0 (0.0) 1 (5.6) 2 (3.1) 3 (3.6) 3 (3.0) Page 97

98 Table 26. Serious Adverse Events Occurring in >= 2 Subjects by Preferred Term (Study HBS407 and Study VSLI-06, N=101) MedDRA Preferred Term - n (%) mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) VSLI-06 (N=7) VSLI-06 (N=18) HBS407 (N=65) Total (N=83) Total (N=101) Anaemia 0 (0.0) 1 (14.3) 0 (0.0) 1 (1.5) 1 (1.2) 2 (2.0) Alanine Aminotransferase Increased 1 (9.1) 1 (14.3) 0 (0.0) 0 (0.0) 0 (0.0) 2 (2.0) Aspartate Aminotransferase Increased 0 (0.0) 1 (14.3) 1 (5.6) 0 (0.0) 1 (1.2) 2 (2.0) Confusional State 0 (0.0) 0 (0.0) 2 (11.1) 0 (0.0) 2 (2.4) 2 (2.0) Enterococcal Bacteraemia 0 (0.0) 0 (0.0) 1 (5.6) 1 (1.5) 2 (2.4) 2 (2.0) Oesophagitis 0 (0.0) 1 (14.3) 1 (5.6) 0 (0.0) 1 (1.2) 2 (2.0) Cardio-Respiratory Arrest 0 (0.0) 0 (0.0) 0 (0.0) 2 (3.1) 2 (2.4) 2 (2.0) Staphylococcal Bacteraemia 0 (0.0) 0 (0.0) 1 (5.6) 1 (1.5) 2 (2.4) 2 (2.0) Failure To Thrive 1 (9.1) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 2 (2.0) Hyperglycaemia 1 (9.1) 1 (14.3) 0 (0.0) 0 (0.0) 0 (0.0) 2 (2.0) Peripheral Motor Neuropathy 0 (0.0) 1 (14.3) 0 (0.0) 1 (1.5) 1 (1.2) 2 (2.0) Source: ISS Table Page 98

99 6.3 Deaths and SAEs across the Remaining Marqibo Experience HBS408 Study HBS408 is an ongoing Phase 2, multicenter, open-label, single arm study of subjects with metastatic malignant uveal melanoma who received Marqibo 2.25 mg/m 2 infused over 1 hour bi-weekly (Cohort 1) or weekly (Cohort 2). Of the 47 subjects in HBS408, 35 subjects (74.5%) died during the treatment period and follow-up, 32 (91.4%) in Cohort 1 and 3 (25.0%) in Cohort 2. Overall, 5 (10.6%) deaths occurred during the treatment period (2 in Cohort 1 and 3 in Cohort 2), and 30 occurred during follow-up (i.e., beyond 30 days after last dose), 30 (85.7%) in Cohort 1 and 0 (0.0%) in Cohort 2. Disease progression was the most common reason for death. In Study HBS408, out of the 44 subjects included in this analysis from the Safety Population, 20 (45.5%) subjects experienced an SAE during the study, 15 (42.9%) subjects in Cohort 1 and 5 (55.6%) subjects in Cohort 2. Overall, the most common SAEs were constipation (6.8%) and ileus (6.8%) VSLI-12 Study VSLI-12 was a Phase 1/2, open-label, single arm, single center study of 7 subjects with histologically confirmed, surgically nonresectable Stage III or IV malignant cutaneous, mucosal (nonchoroidal) or choroidal melanoma and hepatic dysfunction secondary to liver metastases. In Study VSLI-12, all 7 enrolled subjects died during the study, 6 during the treatment period and 1 (Subject 003) during the follow-up period. Six deaths were due to disease progression. There was one event of cardiac arrest. All 7 enrolled subjects experienced an SAE, for a total of 14 SAEs during the study. Among the SAEs that led to discontinuation of study drug, most of the events had a fatal outcome. 6.4 Clinical Laboratory Findings Results of clinical laboratory tests performed in Studies HBS407 and VSLI-06, are presented in this section of the Briefing Document Hematology Absolute Neutrophil Count Among the 83 subjects who were dosed at 2.25 mg/m 2 absolute neutrophil count (ANC) levels declined in the initial week of treatment, partially recovered by the end of Course 1, Page 99

100 and declined slowly throughout Course 2 (i.e., after 8 weeks of treatment). During the 8 weeks of therapy, ANC levels remained generally between 1.5 and /L, and on average above neutropenic ANC levels of /L (Source: ISS Figure ). In Study HBS408, in which subjects were treated with bi-weekly (Cohort 1) or weekly (Cohort 2) Marqibo 2.25 mg/m 2, 9.1% of subjects showed a worsening ANC from Grade 0-3 at baseline (all subjects were Grade 0 at baseline) to a Grade 2 to 4 ANC level during study treatment. Laboratory shifts to grade 3 or 4 occurred in 58 of 91 subjects (63.7%) in the full cohort and 49 of 74 (66.2%) in subjects treated with 2.25 mg/m 2. In responders, 16 of 27 (59.3%) had severe shift (Source: ISS Tables and ). Changes from baseline ANC were evaluated across the entire study duration for subjects treated with Marqibo 2.25 mg/m 2. Among the 83 subjects, 17 (20.5%) showed no change from the baseline CTCAE toxicity grade for ANC, and 53 (63.9%) demonstrated a progression from Grade 0 to 3 toxicity at baseline to Grade 2 to 4 toxicity during study treatment. None of these subjects required dose modification or delay due to neutropenia, and no subject discontinued study drug due to neutropenia (although 1 subject discontinued therapy due to pancytopenia ). Granulocyte growth factors were used at the investigator s discretion and according to local institutional policy. The impact, if any, of growth factor use on the degree or true cause of neutropenia cannot be determined based on available data. There were two deaths associated with decreases in ANC counts. In addition, there were 24 cases of febrile neutropenia and 4 cases of neutropenia that were classified as serious. Page 100

101 Hemoglobin For Course 1, there was a decline in hemoglobin from the baseline value (103.2 g/l [18.24]) to Day 28 (mean change from baseline: g/l [19.54)]) and appeared to plateau throughout Course 2 at ~92-98 g/l (Source: ISS Table ). For Course 3 and Course 4, mean hemoglobin levels were maintained from 84.3 to g/l. From Baseline to the end of the on-treatment period (includes 30 days following last dose of Marqibo ), the overall study hemoglobin levels declined by roughly 6% (mean change from baseline: -6.7 g/l [21.52]) from the Baseline value. Transfusion of red blood cell products was done at the investigator s discretion and per local institutional standards. The impact of transfusions on the degree or true cause of anemia cannot be ascertained based on available data. There were two cases of anemia that were classified as serious and one 1 case of pancytopenia. Platelets For Course 1, platelets declined from the baseline value (median: /L; IQR: 20, 110) to the sixth week of treatment (Course 2, Day 15) (median change from baseline: -0.5; IQR: -60, 72) (Source: ISS Table ). However, platelet levels from the sixth week of treatment increased by the seventh week (Course 2, Day 22) (median change from baseline: +8.5; IQR: -34, 74), but decreased at the eighth week. After Course 2, platelet levels continued to mostly increase; however, the number of subjects was relatively small at these time periods (Course 3: N = 6-14) and Course 4: N = 3-5). Considering the on-treatment period, the overall platelet levels declined to roughly 30% (median change from baseline: 12.0; IQR: -65, 7) of the Baseline value (Source: ISS Table ). This likely reflects ALL progression in the majority of subjects. There were 3 cases of thrombocytopenia that were classified as serious ALT, AST, Alkaline Phosphatase, and Bilirubin There were modest changes from baseline for transaminase, alkaline phosphatase, and bilirubin levels during the on-treatment period (i.e., from first Marqibo dose through 30 days following the last dose). Over the course of the on-treatment period for all 101 subjects, the median change from baseline was 1 U/L (IQR: -8, 17) for alanine aminotransferase (ALT), 1 U/L (IQR: -13, 16) for aspartate aminotransferase (AST), 13.0 U/L (IQR: -12, 65) for alkaline phosphatase, and 1.7 µmol/l (IQR: -1.7, 6.8) for bilirubin (Source: ISS Table ). These changes were not considered to be clinically significant. Page 101

102 Few subjects had shifts of AST, ALT, alkaline phosphatase, or bilirubin to the more severe CTCAE Grades 3 or 4. Among the 101 treated subjects in HBS407 and VSLI-06, elevation of a post-baseline value to Grade 3 occurred for alkaline phosphatase in 3 subjects, for ALT in 9 subjects, for AST in 5 subjects, and for bilirubin in 2 subjects (Source: ISS Table 3.4.5). Elevation to Grade 4 occurred in only 1 subject (elevated bilirubin), who had a history of elevated bilirubin and hepatic transaminases at baseline. Three subjects had elevated liver function test values that were reported as SAEs (subject narratives presented in Appendix D). Two of these subjects had a history of elevated liver function test values prior to treatment with Marqibo and the liver function test value returned to the reference range during Marqibo treatment for one of these subjects Creatinine There was no evidence that Marqibo causes renal insufficiency, with only modest changes from baseline in serum creatinine levels during the on-treatment period. For Course 1, creatinine levels in the total population of 101 subjects steadily decreased from the Baseline value (mean [standard deviation]: 82.3 µmol/l [50.36]) to the first week at Day 8 (change from baseline of mean [standard deviation]: -6.4 µmol/l [23.87]) and continued to decline to Course 1 Day 22 (-12.2 µmol/l [36.17]). At Course 1 Day 28, a minor rise (6.1 µmol/l [18.62]) was observed and then a decline followed by a stable level through to Course 2 Day 22 (-17.9 µmol/l [43.21]). The Course 3 and 4 values fluctuated between a mean change from baseline of -55 to -8 µmol/l. Considering treatment through to Study Termination for all subjects, the overall study creatinine levels approximated Baseline levels (change from baseline of mean [standard deviation]: 1.9 µmol/l [62.94]) (Source: ISS Table ). No subject had a shift in creatinine level to CTCAE Grade 3 or 4 from a lower baseline level (Source: ISS Table 3.4.5) Other Analytes Albumin, sodium, potassium, uric acid, and calcium were monitored by visit. There was not systematic change in any of these analytes (Source: ISS Table 3.4.5). One subject each had an SAE reported based on hyperkalemia, hyperuricemia, and hyponatremia (subject narratives presented in Appendix D). No SAEs associated with albumin or calcium were reported. Page 102

103 6.5 Vital Signs and ECG Findings Table 27 summarizes the vital sign changes in Studies HBS407 and VSLI-06. Overall, a total of 37 subjects (36.6%) experienced a 30 bpm increase from baseline in heart rate, while 15 subjects (14.9%) experienced a 30 bpm decrease from baseline. A total of 23 subjects (22.8%) experienced systolic blood pressure (BP) > 150 mmhg or diastolic BP > 100 mmhg. No subjects experienced a respiration rate change of < 8 breath/minute or > 40 breaths/minute from their baseline value, and 14 subjects (13.9%) experienced a body temperature of > 38.3 C. A total of 42 subjects (41.6%) experienced weight loss of 5% from baseline. Clinically, there were 22 (21.8%) subjects with AE reports of hypotension and 1 subject (1.0%) with decreased blood pressure. Hypotension is associated with vincristine administration. Page 103

104 Table 27. Heart Rate Variable Abnormal Vital Sign Results Observed Any Time During the On-Treatment Period (Study HBS407 and Study VSLI-06, N=101) mg/m mg/m 2 Dose 2.25 mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) < 50 bpm 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 1 (1.0) > 120 bpm 6 (54.5) 2 (28.6) 7 (38.9) 25 (38.5) 32 (38.6) 40 (39.6) 30 bpm increase from baseline 3 (27.3) 4 (57.1) 8 (44.4) 22 (33.8) 30 (36.1) 37 (36.6) 30 bpm decrease from baseline 3 (27.3) 1 (14.3) 3 (16.7) 8 (12.3) 11 (13.3) 15 (14.9) Blood Pressure SBP > 150 mmhg or DBP > 100 mmhg 4 (36.4) 3 (42.9) 3 (16.7) 13 (20.0) 16 (19.3) 23 (22.8) SBP > 200 mmhg or DBP > 110 mmhg 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) SBP < 90 mmhg or DBP < 60 mmhg 4 (36.4) 3 (42.9) 6 (33.3) 20 (30.8) 26 (31.3) 33 (32.7) Respiration Rate < 8 breaths/min 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) > 40 breaths/min 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) Temperature > 38.3 C 1 (9.1) 0 (0.0) 1 (5.6) 12 (18.5) 13 (15.7) 14 (13.9) Change in Weight 5% increase from baseline 0 (0.0) 1 (14.3) 0 (0.0) 1 (1.5) 1 (1.2) 2 (2.0) 5% decrease from baseline 4 (36.4) 1 (14.3) 9 (50.0) 28 (43.1) 37 (44.6) 42 (41.6) DBP = diastolic blood pressure, SBP = systolic blood pressure Source: ISS Table 3.5. Page 104

105 In HBS407, electrocardiograms (ECGs) were analyzed from subjects who had undergone up to 3 courses of therapy with Marqibo. The variables (time intervals) measured were heart rate, PR interval, QRS duration, QT interval, QT corrected for heart rate using Bazett s formula (QTcB) duration, and QT corrected for heart rate using Fridericia s formula (QTcF) duration. There was no evidence of any effect on the ECG by Marqibo. The change from the mean pre-dose QTcF duration on Course 1, Day 1 to the 2-4 hour post-dose QTcF duration was 4.3 msec. Two male subjects had a QTcF value greater than 450 msec. One subject (No. 0814) had a baseline QTcF of 445 msec and a QTcF of 476 msec on Course 1, Day 8, predose. The second subject (No. 0816) had a baseline QTcF of 404 msec and a QTcF of 454 msec on Course 2, Day 22, pre-dose. In Study HBS408, subjects enrolled in Cohort 2 (Marqibo 2.25 mg/m 2 weekly, N=12) were monitored for cardiac safety (using Holter monitors) beginning 24 hours prior to the first dose of Marqibo and continuing for 24 hours after the start of the first infusion. Blood samples were collected for PK analysis in conjunction with cardiac Holter monitoring. The primary focus of this analysis was the change from time-matched baselines in the QTcF and the secondary endpoints were change from baseline in: PR interval; QRS duration, absolute QT values; and QTcB duration. Subjects were monitored for cardiac safety using 12- lead ECGs at the following 17 time points: -24h, -23h 45m, -23h 30m, -23h 15m, -23h, -22h, -18h, -14h, 0m pre-marqibo ; and 15m, 30m, 45m, 1h, 2h, 6h, 10h, and 24h post-marqibo. In addition, PK data were compared to ECG results to investigate whether there was any correlation between plasma concentrations of Marqibo and ECG parameters measured. There was no evidence of any QT effects of Marqibo in a 48-hour Holter (24 hour baseline and 24 hour post-marqibo ) in the 12 most intensively treated subjects. There was no evidence that Marqibo at the MTD (mg/m 2 or total mg infused) was associated with any potentially clinically significant changes in ECG variables in active cancer subjects treated at the most intensive dose (2.25 mg/m 2 without modification). 6.6 Special Safety Topics Neuropathy Peripheral neuropathy is a known vincristine-related AE linked to cumulative vincristine exposure. Based on this safety risk, investigators used a 15-item neurological assessment tool to evaluate subjects for peripheral neuropathy at baseline and prior to each dose of Marqibo. Investigators assessed subjects for 7 neurological symptoms (i.e., weakness, pain, jaw pain, numbness paresthesia, constipation, and postural hypotension), which were scored based on a Page 105

106 4-point scale and 8 neurological signs (i.e., brachioradialis, biceps, knee, and ankle reflexes, vibration-first toe, strength-extension of wrist, strength-dorsiflexion of foot, and gait), which were scored on a 4-point scale. In addition, all reported AEs were screened for predefined Medical Dictionary for Drug Regulatory Activities (MedDRA) preferred terms to capture possible peripheral neuropathy that may not have coded as such. All potential cases of peripheral neuropathy were tracked until resolution or until they were considered chronic. Table 34 (Supplemental Table in Appendix E) lists the MedDRA preferred terms that were used to define baseline and treatment emergent AEs that could indicate neuropathy. Neuropathy history or condition was reported for the majority (80%) of subjects prior to receipt of Marqibo 2.25 mg/m 2, with pain (32.5%), asthenia (27.7%), areflexia (24.1%), hypoesthesia (24.1%), hyporeflexia (24.1%), and paresthesia (20.5%) being the most common neuropathies (Source: ISS Table ). Constipation was reported with an overall incidence of 19.3% as a baseline condition. In general, similar rates of neuropathy conditions were reported by history or identified by neurological examination, although some events appeared at a higher frequency when identified by active investigation. Of the 101 subjects in Studies HBS407 and VLSI-06, 88 (87.1%) reported a neuropathyassociated treatment-emergent AE during the treatment period (Source: ISS Table ). Constipation (57.4%), which is conservatively assumed to represent a possible autonomic neuropathy, was the most frequently reported AE. Other frequently reported neuropathy AEs included peripheral neuropathy (38.6%), paresthesia (21.8%), hypoesthesia (19.8%), asthenia (18.8%), arthralgia (17.8%), and myalgia (17.8%). Of the 83 subjects on 2.25 mg/m 2, 72 (86.7%) reported a neuropathy-associated AE during the treatment period. The most common neuropathy-associated AEs for subjects being treated with Marqibo 2.25 mg/m 2 were constipation (56.6%), peripheral neuropathy (37.3%), paresthesia (22.9%), hypoesthesia (22.9%), asthenia (19.3%), arthralgia (18.1%), and myalgia (14.5%). The number of subjects receiving mg/m 2 and 2.4 mg/m 2 was too small to reliably compare the relative frequencies of AEs across dose groups. However, the types of AEs most frequently reported were qualitatively similar across dose levels. Table 28 shows the neuropathy-associated AEs that were classified as at least grade 3 and Table 29 shows the incidence of neuropathy-related SAEs. There were 27 subjects (32.5% of the 83 treated with 2.25 mg/m 2 ) with a grade 3 AE suggestive of neuropathy and 11 subjects (13.3% of the 83 treated with 2.25 mg/m 2 ) with an SAE(s) suggestive of neuropathy. Page 106

107 Table 28. Neuropathy Adverse Events of Grade >= 3 Severity (Study HBS407 and Study VSLI-06, N=101) System Organ Class Preferred Term Any Grade 3 Neuropathy- Related Adverse Event mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) 1 (9.1) 1 (14.3) 3 (16.7) 24 (36.9) 27 (32.5) 29 (28.7) Neuropathy Peripheral 1 (9.1) 0 (0.0) 0 (0.0) 10 (15.4) 10 (12.0) 11 (10.9) Peripheral Motor Neuropathy 0 (0.0) 1 (14.3) 1 (5.6) 2 (3.1) 3 (3.6) 4 (4.0) Constipation 0 (0.0) 0 (0.0) 2 (11.1) 2 (3.1) 4 (4.8) 4 (4.0) Asthenia 0 (0.0) 0 (0.0) 0 (0.0) 4 (6.2) 4 (4.8) 4 (4.0) Ileus 0 (0.0) 0 (0.0) 0 (0.0) 3 (4.6) 3 (3.6) 3 (3.0) Gait Disturbance 1 (9.1) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 2 (2.0) Pain In Extremity 0 (0.0) 0 (0.0) 0 (0.0) 2 (3.1) 2 (2.4) 2 (2.0) Areflexia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Decreased Vibratory Sense 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Hypoaesthesia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Neuralgia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Paraesthesia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Peripheral Sensory Neuropathy 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Colonic Pseudo-Obstruction 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Subileus 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Arthralgia 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Muscular Weakness 0 (0.0) 0 (0.0) 1 (5.6) 0 (0.0) 1 (1.2) 1 (1.0) Source: ISS Table Page 107

108 Table 29. Any Neuropathy-Related Serious Adverse Events (Study HBS407 and Study VSLI-06, N=101) System Organ Class Preferred Term Any Neuropathy-Related Serious Adverse Event mg/m mg/m mg/m 2 Overall VSLI-06 (N=11) n (%) VSLI-06 (N=7) n (%) VSLI-06 (N=18) n (%) HBS407 (N=65) n (%) Total (N=83) n (%) Total (N=101) n (%) 1 (9.1) 1 (14.3) 1 (5.6) 10 (15.4) 11 (13.3) 13 (12.9) Neuropathy Peripheral 1 (9.1) 1 (14.3) 0 (0.0) 4 (6.2) 4 (4.8) 6 (5.9) Constipation 0 (0.0) 0 (0.0) 1 (5.6) 2 (3.1) 3 (3.6) 3 (3.0) Peripheral Motor Neuropathy 0 (0.0) 1 (14.3) 0 (0.0) 1 (1.5) 1 (1.2) 2 (2.0) Facial Palsy 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Peripheral Sensory Neuropathy 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Ileus 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Subileus 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Gait Disturbance 0 (0.0) 0 (0.0) 0 (0.0) 1 (1.5) 1 (1.2) 1 (1.0) Source: ISS Table A number of subjects had normal reflexes at baseline and went on to have absent reflexes during the study. Of 57 subjects with normal patellar reflexes at baseline, 10 were found to be absent during treatment with Marqibo 2.25 mg/m 2. Likewise, of 57 subjects with normal ankle reflexes at baseline, 10 were found to be absent during treatment (Source: ISS Table ). With regard to neurological symptoms, there was some shift from baseline scores for most of the symptoms monitored. The largest shifts were seen with paresthesia and numbness. Of 74 subjects with no paresthesia complaints at baseline, 3, 10, and 18 subjects reported severe, moderate, and mild symptoms, respectively, during treatment with Marqibo. A similar pattern was observed for numbness (Source: ISS Table ). The earliest symptom manifestations of neuropathy (i.e., neuralgia, facial neuralgia, myalgia, oral hypoesthesia, constipation, subileus, and ileus) occurred within 2 weeks of Marqibo initiation (Source: ISS Table ). The instances of constipation and ileus, though, may have been complicated by the extensive use of opiate analgesics. Between 2 and 4 weeks (Course 1, Days 15 to 28) was the median onset of AEs of hypoesthesia, paresthesia, peripheral neuropathy, cranial neuropathy, asthenia, muscular weakness, myalgia, extremity pain, tremor, facial palsy, hyporeflexia, areflexia, speech disorder, blurred vision, colonic pseudo-obstruction, and gait disturbance. Page 108

109 The frequency of peripheral neuropathy (MedDRA preferred term of neuropathy peripheral) appeared to be related to cumulative dose. Peripheral neuropathy occurred in 2.4% of subjects with cumulative doses < 6.66 mg while at 19.2 mg the frequency was 21.4%. There were no incidents of AEs that coded to the preferred terms of peripheral sensory neuropathy or peripheral motor neuropathy, at the lowest doses of < 6.66 mg, while at the highest doses of 19.2 mg, the incidence of those events was 7.1% for each preferred term. Other reported preferred terms suggestive of neuropathy and potentially having a relationship to cumulative dose include hypoesthesia and areflexia. Hypoesthesia developed in 2.4% of subjects at < 6.66 mg cumulative dose and in 11.9% at cumulative doses 19.2 mg. Areflexia occurred in no subjects at cumulative doses < 6.66 mg, in 3.8% of subjects at cumulative doses of 6.66 mg to < mg, and in 7.1% of subjects at cumulative doses 19.2 mg. For the other Nervous System preferred terms, the frequencies were variable and the absolute number of cases was small, making it difficult to ascertain if a relationship to cumulative dose was present. One non-nervous System preferred term, asthenia, showed an apparent relationship to cumulative dose, occurring in 1.2% of subjects at < 6.66 mg, progressively increasing to 11.9% of subjects at doses 19.2 mg. Dose reductions in subjects with neuropathy are discussed in Section Infections Of 101 subjects, 58 had at least one AE consistent with infection. Overall, the most frequently reported AEs within the Infections and Infestations System Organ Class (SOC) included pneumonia (11.9%) and bacteremia (10.9%) (Source: ISS Table 3.2.3). The frequency of pneumonia among all Marqibo -treated subjects is comparable to rates expected in this patient population. Kantarjian et al (2000) reported that pneumonia occurred in 22% of adults with newly diagnosed ALL treated with hyper-cvad (cyclophosphamide, standard formulation vincristine, doxorubicin, and dexamethasone, alternatively high-dose methotrexate and cytarabine). Rossini et al (2000) similarly reported a pneumonia rate of 23.8% during induction therapy in a population of acute myelogenous leukemia and ALL patients treated with a variety of chemotherapy regimens Cardiovascular A total of 31 subjects (30.7%) of the 101 subjects in HBS407 and VSLI-06 experienced treatment-emergent AEs that were classified in the cardiac disorder SOC category (Source: ISS Table 3.2.3). The most frequently occurring AEs overall were tachycardia (19.8%), cardiac arrest (5.0%), pericardial effusion (3.0%), and sinus tachycardia (3.0%). No evidence of a dose response was observed in the incidence rate of any individual cardiac AE. Page 109

110 Of the 31 subjects with cardiovascular AEs overall, 9 subjects (8.9%) reported cardiovascular AEs with CTCAE Grade 3, 3 subjects (3.0%) reported treatment-related cardiovascular AEs, 8 subjects (7.9%) reported cardiovascular AEs classified as serious (1 treatment-related), and 1 subject was discontinued from study drug due to a cardiovascular AE (Source: ISS Tables through 3.2.7, Tables through , and Table ). As mentioned in Section 6.2.3, 4 subjects died due to a cardiac arrest, all having pre-existing risk factors for the event (e.g., diabetes, hypertension, obesity) (narratives presented in Appendix D). Three of the events occurred after study drug was discontinued; the investigator considered these 3 events as unrelated to study drug. In the 1 case of cardiac arrest that the investigator believed to be related to study drug, the event occurred 6 days after the subject s third infusion of Marqibo during a clinic visit. Despite a history of ongoing pericardial effusion, the subject had a normal cardiac examination at the time of last prior Marqibo infusion and had no known other cardiac history. On the day of the last Marqibo infusion, the potassium concentration was 3.7 meq/l, creatinine was 1.99 mg/dl, and white blood cell (WBC) count was /L. Laboratory values at the time of the cardiac arrest 6 days later are not known. Cardiac arrest has been reported in an ALL patient secondary to hyperkalemia (Wilson et al 1977). Limited information, including laboratory tests and ECGs, is available concerning the subject s condition immediately prior to the cardiac arrest. It is not known, for example, if the pericardial effusion progressed to cardiac tamponade. Based on the lack of a history of cardiac disease and the limited information available, the investigator considered the event possibly related to study drug Hepatobiliary A total of 10 subjects (9.9%) in Studies HBS407 and VSLI-06 reported an AE occurring in the Hepatobiliary Disorders SOC (Source: ISS Table 3.2.3). The most common hepatobiliary event was hyperbilirubinemia, which occurred in 8% of subjects in VSLI-06, 3.1% of subjects in HBS407, and in 5% of all 101 subjects. There was no evidence of a dose-related effect on the occurrence of hyperbilirubinemia. Of the 10 subjects with hepatobiliary AEs, 5 (5.0%) reported hepatobiliary AEs with CTCAE Grade 3, 3 (3.0%) reported treatment-related hepatobiliary AEs, 2 (2.0%) reported hepatobiliary AEs classified as serious (one treatment-related), and 1 discontinued study drug due to a hepatobiliary AE (Source: ISS Tables through 3.2.7; Tables through ; and Table ). No subject died due to a hepatobiliary AE (Source: ISS Table ). Page 110

111 There was a single occurrence of acute cholecystitis in a subject treated with Marqibo 2.4 mg/m 2 in VSLI-06. This subject had an elevated (Grade 3) ALT level at study entry, which decreased to Grade 2 at the onset of the acute cholecystitis. In addition, pancreatitis was diagnosed coincident with the acute cholecystitis. The investigator did not consider the acute cholecystitis to be related to study drug. The acute cholecystitis was identified 7 days after initiation of study drug, in the presence of an elevated ALT level since baseline, making it likely that this condition was evolving prior to administration of Marqibo. One subject (in HBS407) developed chronic acalculous cholecystitis 39 days after initiation of treatment with VSLI 2.25 mg/m 2. No other acute conditions were reported accompanying the diagnosis. The subject had no reported medical history of cholecystitis; however, abdominal pain was present for 3½ years prior to study entry. The investigator considered the chronic cholecystitis to be related to study drug. Gallbladder edema was diagnosed in one subject 5 days after initiation of Marqibo 2.25 mg/m 2 (HBS407). Grade 3 elevations of ALT and AST and nausea were identified the same day. The gallbladder edema was preceded by events of vomiting and abdominal pain on Days 3 and 4, respectively, and followed by a Grade 2 elevation of total bilirubin on study Day 8. The investigator considered the gallbladder edema to be not related to study drug. Hepatomegaly was reported in one subject on Day 21 of Marqibo 2.25 mg/m 2 (HBS407). The event was preceded by splenomegaly, which was reported one week prior. The investigator considered the hepatomegaly unrelated to study drug, and likely the result of extramedullary (liver and spleen) infiltration by leukemic blasts. Jaundice was reported in one subject on Day 20 of Marqibo 2.25 mg/m 2 (HBS407). This subject had undergone an allogeneic HSCT in second remission and as the line of antileukemia therapy immediately prior to Marqibo. This subject developed graft-versus-host disease (GVHD) exacerbation on study Day 8, which continued to worsen to Grade 3 by study Day 11, and to Grade 4 by study Day 19. The investigator considered the jaundice related to study drug. However, considering that the jaundice appeared after the GVHD flare reached Grade 4 severity, it is more likely that the jaundice was a consequence of the severe GVHD rather than study medication. Four subjects (4.0%) were identified with ALT/AST, bilirubin, and alkaline phosphatase levels that were consistent with Hy's Law criteria (Zimmerman 1978, Zimmerman 1999). All 4 subjects had potentially confounding factors, such as prior or concomitant administration of potentially hepatotoxic drugs (e.g., cytarabine, methotrexate, quetiapine, itraconazole, Page 111

112 fluconazole) and comorbidities (sepsis/hypotension/metabolic acidosis in one subject and the potential for leukemic infiltration of the liver in all subjects). Information on the 4 cases identified from the Marqibo dataset did not include additional details concerning liver biopsy results or virology testing. However, considering the general lack of an hepatotoxic effect from prior clinical experience with vincristine (King and Perry 2001), the potential contribution of other prior chemotherapy agents, and the potential effect of leukemic infiltration, it would appear unlikely that the biochemical manifestations that appear consistent with a Hy s law case actually represent a potential hepatotoxic effect of Marqibo (Comeau and Phillips 2005) Renal A total of 21 subjects (20.8%) reported treatment-emergent AEs that were classified in the Renal and Urinary Disorders SOC category (Source: ISS Table 3.2.3). The most frequently occurring renal AEs overall were dysuria (4.0%), renal failure (4.0%), and urinary incontinence (4.0%). Of the 21 subjects with renal AEs overall, 8 subjects (7.9%) reported renal AEs with CTCAE Grade 3, 3 subjects (3.0%) reported treatment-related renal AEs, 3 subjects (3.0%) reported renal AEs classified as serious (1 treatment-related; subject narrative presented in Appendix D), and 1 subject had study drug discontinued due to a renal AE (Source: ISS Tables through 3.2.7, Table through , and Table ). No subject died due to a renal AE (Source: ISS Table ). Renal dysfunction at presentation reflected documented kidney infiltration by leukemic blasts in a few cases. Renal leukemic involvement resulting in renal dysfunction has been described by others (Ellman et al 1974, Kanfer et al 1976, Randolph et al 1983, Glicklich et al 1986, and Bathla et al 2009). Page 112

113 7. Post-approval Commitment Study of Subjects 60 Years of Age with Newly Diagnosed ALL The post-approval commitment study for Marqibo (TTX404) is an international, multicenter, open-label, randomized, controlled trial with 2 treatment arms that vary only in the administration of standard vincristine vs. Marqibo. The study is designed to evaluate the substitution of Marqibo for standard vincristine sulfate injection in the induction, intensification, and maintenance phases of combination chemotherapy in the treatment of elderly subjects ( 60 years old) with newly diagnosed, histologically proven, untreated Ph- ALL, with 5% bone marrow blasts ALL. Marqibo will be dosed at 2.25 mg/m 2 as an IV infusion over 60 minutes. Standard vincristine will be dosed at 1.4 mg/m 2 with a 2 mg dose cap as IV infusion over 10 minutes. Dose reduction in response to documented neuropathy or other toxicity will be allowed and determined by a protocol-specified dosing modification algorithm. TTX404 initiated recruitment in the fourth quarter of 2011 and is projected to complete in approximately 4 years. Figure 12. Design Schematic for Study TTX404 A synopsis of key elements of Study TTX404 is presented in Appendix F. Page 113

114 8. Risk Management Plan Risk management activities will focus on communication of the Marqibo safety profile within the label and patient educational materials. This includes communication of the dose reduction algorithm to treating physicians, to help them recognize and better manage peripheral neuropathy. As a vincristine product, there is the risk that users may confuse Marqibo and standard generically available vincristine. To minimize this risk, Marqibo packaging and vial will be visually distinct from that of standard vincristine and warnings/alerts will be placed on the package, label, and vial of Marqibo with the correct 2.25 mg/m 2 dosing. In addition, dosing information including an alert that dosing is different from vincristine will be included within the materials, as will a toll-free phone center to answer any medical inquiries or reports. The proposed, post-approval clinical trials will further characterize Marqibo safety relative to vincristine in adult and pediatric patients; findings from these trials will be added to the label and educational resources. These safety assessments will be augmented by standard safety surveillance activities. The risk management actions will: communicate information to support informed consent and an understanding of Marqibo benefit-risk; limit the potential risk of confusion with standard vincristine; and continue to gather controlled data to better understand Marqibo risk. Page 114

115 9. Benefit/Risk Conclusion With current multi-agent chemotherapy regimens, up to 90% of newly diagnosed adult ALL patients will achieve an initial CR+CRi, however only 28% to 39% achieve long-term disease control (Gokbuget and Hoelzer 2002). Relapse, which commonly follows initial remission, is associated with poor prognosis; survival probability and duration decreases following each subsequent relapse. Patients in their second ALL relapse or ALL first relapse that is refractory to a line of therapy have a median expected survival of no more than 3 months (O Brien et al 2008). For patients in third or fourth relapse or in a second relapse that is refractory to therapy, survival is expected to be days to weeks. Thus, there is a significant unmet medical need for a new therapy that delivers improved efficacy with a predictable and manageable safety profile in advanced, relapsed and/or refractory Ph- adult ALL. Vincristine is a potent agent in lymphoid malignancies. The FDA labeled dose is 1.4 mg/m 2. Larger individual doses as well as increased cumulative doses and dose density have produced enhanced efficacy, but the increased doses are associated with near universal doselimiting neuropathy including constipation. Thus, despite high activity against ALL in vitro, the anti-leukemia activity of standard vincristine is limited by a narrow therapeutic index. In fact, the standard of clinical practice is to dose cap to 2 mg. Based on a dose of 1.4 mg/m 2, a 2 mg dose cap reflects significant under dosing for the large population of adults whose body surface area (BSA) exceeds 1.43 m 2. Talon designed Marqibo to target the delivery of a larger total dose of vincristine to tumor cells by encapsulating vincristine within the aqueous core of a unique, nanoparticle, sphingomyelin and cholesterol liposomes. In animal studies, administration of Marqibo produced markedly increased plasma total (encapsulated plus free) vincristine levels compared to standard vincristine because of decreased clearance, resulting in prolonged plasma circulation time. Additional animal studies found that Marqibo delivers larger amounts of vincristine, for an extended period of time, to tissues that are most commonly affected by ALL (i.e., bone marrow, lymph nodes, and spleen) and observed a greater tumor response with Marqibo when administered at the same dose as standard vincristine. The anti-tumor effect of Marqibo was dose-dependent and larger doses of Marqibo could be infused and tolerated than of standard vincristine. The animal toxicological profile of Marqibo was similar to that observed with vincristine, with no new or unexpected toxicity. In clinical pharmacology studies, the total amount of vincristine (encapsulated plus free) delivered by Marqibo has a longer elimination half-life and significantly larger area under the curve (AUC) compared to standard vincristine. With Marqibo, vincristine is retained in Page 115

116 the circulation in an encapsulated form and concentrations of released vincristine in plasma are undetectable at most time points, findings that are consistent with reduced immediate bioavailability. Given the nonclinical findings and supportive Marqibo clinical pharmacology observations, Talon designed the Marqibo clinical development program to affirm an increase in clinical benefit given the likely increased exposure to cancer cells. An increase in the vincristine therapeutic index, which results from an increase in efficacy without a corresponding increase in toxicity, could lead to a new Ph- ALL treatment paradigm. Study HBS407 enrolled 65 heavily pretreated adults (age range 19 to 83 years; ECOG performance status range: 0 to 3) with advanced, relapsed and/or refractory Ph- ALL requiring third, fourth, fifth or greater line of therapy. All 65 patients had previously treatment with standard vincristine. The HBS407 study population represents the most advanced and unfavorable adult ALL population studied to date. The following subject characteristics reflect the advanced nature of their underlying ALL and challenges to continued treatment: 100% had prior exposure to standard vincristine; 51% had already received 3 or more lines of anti-leukemia therapy; Subjects had received a median of 10 (range 4 to 15) different prior drugs with near universal prior exposure to steroids, anthracyclines, cyclophosphamide, and cytarabine ; 48% had relapsed following one or two prior transplants; 45% were refractory to their immediate prior line of therapy; 62% were CD34+ on immunophenotype analysis, which is reported to adversely affect outcome (Czuczman et al 1999); 59% of cytogenetic profiles were unfavorable and none were favorable; and, 80% had residual vincristine associated neuropathy at study entry. In the primary ITT analysis using response data assessed by PIs, 20% (13/65, [95% CI 11.1, 31.8]) achieved complete response (CR+Cri). The IRRC corroborated clinical responses in 11 Page 116

117 of the 13 cases of CR+CRi. The other 2 subjects were assessed by the IRRC as having bone marrow blast (BMB) responses, which represent morphological CR without recovery of both the neutrophil and platelet counts (called CR* in studies of nelarabine in T-cell ALL). The CR+CRi rate when using IRRC assessment was 16.9% (11/65, [95% CI 8.7, 28.3]). Regardless of whether using PI or IRRC assessment, the lower bound of the 95% CI is greater than 7.5%, which was the primary statistical test of efficacy. In HBS407, Marqibo monotherapy demonstrated efficacy even in patient subsets with the poorest prognosis, including those with refractory disease and those in need of third, fourth, and fifth or greater line therapy. Complete response rates were comparable at 19%, 21%, and 22% in the 32, 24, and 9 subjects who received Marqibo as third, fourth, and fifth or greater line of therapy, respectively. Four of 29 (14%) of subjects with relapsed ALL refractory to one or more immediate prior lines of therapy achieved CR+CRi as a result of Marqibo monotherapy. In addition to Marqibo 2.25 mg/m 2 monotherapy producing clinically meaningful response rates, the duration of responses in HBS407 compared favorably as well. For the 13 subjects in Study HBS407 who achieved CR+CRi per the primary analysis and the 11 subjects in Study HBS407 who achieved CR+CRi based on IRRC assessment, the median duration of remission was 23 weeks, with a maximum duration of remission well over one year (66 weeks). This median duration of remission is more consistent with expectations for a population in first relapse in need of second-line (first salvage) therapy (Thomas et al 1999) and not one entirely (100%) composed of subjects in need of third or greater line of therapy. Additionally, 9 (69%) subjects in HBS407 who attained a CR+CRi from Marqibo had a response duration that exceeded the duration of response to their immediately prior line of ALL therapy. This pattern contrasts with the normal pattern of successive response durations being significantly shorter than the previous response. The median overall survival in the ITT population (N = 65) was 4.6 months and in those achieving CR+CRi (N = 13) was 7.7 months (range 2.4 to months). Five subjects had overall survival in excess of 1 year as a result of Marqibo monotherapy. In 12 subjects transplantation was performed a median of 3.1 months after beginning Marqibo monotherapy. Page 117

118 There are no controlled studies in this patient population to allow a comparison of response rates, duration of response and survival with the experience observed with Marqibo in HBS407. However, a retrospective study of 288 relapsed and/or refractory patients, all in need of 3 rd line ALL therapy, treated at M.D. Anderson Cancer Center (MDACC) (O Brien et al. 2008) provides a cohort with the closest approximation to the study population of HBS407. In the MDACC study, there was a population of 70 B-cell and T-cell lineage ALL patients who most closely compared to the HBS407 ALL population. Key similarities include the exclusive use of monotherapy and the fact that greater than 50% of subjects in both groups had 3 or 4 recognized adverse prognostic factors such as duration of first CR of less than 36 months, platelet count less than 50 x 10 9 /L at relapse, and greater than 50% bone marrow blasts at relapse (O Brien et al 2008). Key differences include the fact that 15 of the 70 (79%) MDACC single-agent treated group were in a first relapse in contrast to the 58% of HBS407 subjects who were in second or greater relapse. All of the MDACC group was evaluated in the context of third-line therapy, while HBS407 evaluated Marqibo as third, fourth, or fifth or greater line of therapy. These differences, combined with more ALL pretreatment in HBS407 subjects and a higher proportion of subjects who had previously received and progressed following transplantation in HBS407, makes the comparison conservative. Key outcomes comparisons include: The complete response rate in Study HBS407 as a result of weekly, single-agent Marqibo 2.25 mg/m 2 (20.0%) was ~ 4.7-fold greater than was observed in the MDACC single-agent group (4.3%) and comparable to that observed among the MDACC patients treated with multi-agent therapy (20.9%). The early plus induction (30-day) mortality rate with single-agent Marqibo 2.25 mg/m 2 (12.3%) was about half that for single-agent (24.2%) and multi-agent therapies (22%) used at MDACC. Median overall survival was longer with Marqibo monotherapy in HBS407 (4.6 months) than was observed with single- and multi-agent therapy at MDACC (2.1 and 3.3 months, respectively). Thus, based upon a conservative comparison with published literature (O Brien et al 2008), Marqibo provides greater clinical benefit than the expected experience with a single agent and has the potential to advance the care of patients with Ph- Adult ALL. Additional findings from HBS407 are as follows. Doses were administered in an outpatient setting 72% of the time. The individual doses (median 4.12 mg [range 3.14 to 5.51 mg]), Page 118

119 cumulative doses (median mg [range 3.5 to mg]), and dose densities (median 2.25 mg/m 2 /week [range 0.94 to 2.29 mg/m 2 /week]) of Marqibo delivered in Study HBS407 significantly exceeded the standard vincristine dosing. In HBS407, 72% were administered in the out-patient setting. This is in contrast to other agents administered in this setting that result in cytopenias that require in-patient supportive care. Supportive evidence of efficacy was observed in Study VSLI-06, a Phase 1/2 dose-escalation study conducted in a heterogeneous population of relapsed and/or refractory (advanced) ALL subjects (one Ph+ subject, two Burkitt s lymphoma/leukemia subtypes, subjects with primary refractory ALL, and subjects in need of first salvage [38.9%]). Marqibo (1.5 to 2.4 mg/m 2 ) was combined with pulse dexamethasone 40 mg. In this group of subjects who also had universal prior vincristine exposure, Marqibo 2.25 mg/m 2 once weekly induced a CR, partial response (PR), or hematologic improvement (HI) response in 33.3% and CR rate of 16.7% based on PI assessment. The toxicity profile of weekly Marqibo 2.25 mg/m 2 is consistent with expectations based on vincristine treatment and/or clinical characteristics of the study population. No new or unexpected toxicities were identified for Marqibo. Marqibo is associated with neuropathy including constipation. Considering the Marqibo individual and cumulative dose-intensities and dose-density delivered, one might have expected Grade 3 or greater peripheral neuropathy and constipation incidences in excess of 50%. Among the 31 subjects (37.3%) treated with Marqibo 2.25 mg/m 2 who reported new or worsening neuropathy during the study period, 10 (32.3%) had peripheral neuropathy of Grade 3 severity. This pattern extended to most of the neuropathy-associated AE terms. This pattern is particularly meaningful because of universal prior vincristine exposure resulting in evidence of residual (mostly Grade 1) neuropathy in 80% of subjects at baseline just prior to the initiation of Marqibo. Figure 13 provides a summary of the efficacy of Marqibo in Study HSB407according to predosing and postdosing peripheral neuropathy status. Particular attention was paid to whether or not on-study peripheral neuropathy AEs resulted in dose reduction or discontinuation. Figure 13 reveals that patients who developed peripheral neuropathy that required dose reduction or discontinuation also experienced some of the highest CR/CRi rates. Page 119

120 Figure 13 Summary of Efficacy and Safety in HBS407 Source: and Thus, the evidence from HBS407 and VSLI-06 is reasonably likely to predict clinical benefit to patients with Ph- adult ALL in second or greater relapse or that has progressed following two or more lines of anti-leukemia therapy. Weekly administration of Marqibo 2.25 mg/m 2 is not associated with prohibitive risks to patients with Ph- adult ALL in second or greater relapse or that has progressed following two or more lines of anti-leukemia therapy. The Marqibo data combined with the post-approval commitment meet all the ODAC criteria for accelerated approval based on single-arm trials (Food and Drug Administration 2011). Specifically: Page 120