Clinical evaluation of therapeutic cancer vaccines

Transcription

1 Human Vaccines & Immunotherapeutics ISSN: (Print) X (Online) Journal homepage: Clinical evaluation of therapeutic vaccines Chizuru Ogi & Atsushi Aruga To cite this article: Chizuru Ogi & Atsushi Aruga (2013) Clinical evaluation of therapeutic vaccines, Human Vaccines & Immunotherapeutics, 9:5, , DOI: /hv To link to this article: Published online: 01 Mar Submit your article to this journal Article views: 283 View related articles Citing articles: 9 View citing articles Full Terms & Conditions of access and use can be found at Download by: [ ] Date: 31 December 2017, At: 14:54

2 Research paper Human Vaccines & Immunotherapeutics 9:5, ; May 2013; 2013 Landes Bioscience research paper Clinical evaluation of therapeutic vaccines Chizuru Ogi and Atsushi Aruga* Cooperative Major in Advanced Biomedical Sciences; Joint Graduate School of Tokyo Women s Medical University and Waseda University; Tokyo, Japan Keywords: therapeutic vaccine, immunotherapy,, prognostic factor, clinical trials, phase III, regulatory science Downloaded by [ ] at 14:54 31 December 2017 Therapeutic vaccines are an immunotherapy that targets tumor antigens to induce an active immune. To date, Provenge is the only therapeutic vaccine approved by the United States Food and Drug Administration. Although therapeutic vaccines have not been approved by the European Medicines Agency (EMA), they have been approved in several countries other than the United States (US) and the European Union (EU). Provenge is the only approved vaccine that showed significant primary endpoint efficacy in a phase III study at the time of approval. Retrospective analysis of 23 completed or terminated phase III studies showed that 74% (17/23) failed to demonstrate significant efficacy in the primary endpoint. The reasons for failure were surveyed in 13 of the 17 studies. Despite efforts to minimize tumor burden, including surgery and induction chemotherapy before therapeutic vaccine therapy, 69% (9/13) of the phase III studies failed. These findings indicate that tumor burden may not be the only prognostic factor. Immunological has often been used as a predictive factor, and a small number of sub-group analyses have succeeded in showing that immunological is associated with the efficacy of therapeutic vaccines. Being a prognostic factor, inclusion of immunological in addition to tumor stage in the eligibility criteria or sub-group analysis may minimize study population heterogeneity, a key factor in the success of phase III studies. Introduction According to the World Health Organization (WHO), is still a leading cause of death worldwide, responsible for 7.6 million deaths (13% of all deaths) in The Surveillance, Epidemiology and End Results (SEER) program in the United States (US) reported that from 2002 to 2008, the overall 5-y relative survival rate for was only 65.4%. Thus, the discovery of novel therapies to prolong survival, or to provide curative treatment for cases with no satisfactory alternatives, is still essential. Since the approval of herceptin (anti-her2 ) by the FDA (Food and Drug Administration) in 1998, other -based drugs, showing reasonable tolerability and efficacy, have been successfully launched. Antibody-based drugs are categorized as passive specific immunotherapy. Targeted drugs such as these are expected to reduce safety risks for normal cells and to improve efficacy compared with cytotoxic chemotherapies. Therapeutic vaccines are categorized as active specific immunotherapeutic agents; they selectively target tumor antigens to induce an active immune. Although, therapeutic vaccines have been in development for several decades, few vaccines have been approved. In 2010, Provenge was the first vaccine to be approved by the US FDA. Therapeutic vaccine formulations are categorized into 3 categories: cell, gene and protein/peptide. Cell. Cell formulations consist of patient-derived tumor cells and dendritic cells (DC) that mimic tumor antigens to stimulate the patient s immune system. Tumor cell vaccines are derived from patient tumors and are detoxified. After processing, they are injected into patients as a tumor antigen to stimulate an immune. Dendritic cells (DC) are the dominant antigen presenting cells (APCs) that induce T-cell activation. Exposure of DCs to tumor antigens in vitro leads to the presentation of tumor antigens on major histocompatibility complex (MHC) molecules on their surface; these cells are then re-injected into patients. Thus, cell formulations require cell processing despite the presence of MHC, to elicit a to tumor antigens. Gene. Gene formulations involve gene transfer of tumor antigen using plasmid DNA, viruses, or bacteria. Gene transduction of tumor antigen is expected to immunize patients. Protein/peptide. Protein/peptide formulations of tumorassociated antigens bind to MHC in vivo and are used to trigger an immune in patients. is another type of this formulation. antibodies bind to immunoglobulins in the hypervariable region, which is associated with individual antigenicity. Protein/peptide formulations are thought to mimic the structure of antigen determinants and acts like tumor antigens in vivo. Although there are a variety of therapeutic vaccine formulations, the intended effect of all formulations is to induce or amplify the host immune in vivo. While general regulatory guidelines for each type of formulation have been developed to some extent, there are few guidelines on clinical evaluation methods for therapeutic vaccines, although the FDA has issued recommendations for industry guidance, Clinical Considerations for Therapeutic Cancer Vaccines in We *Correspondence to: Atsushi Aruga; aruga@abmes.twmu.ac.jp Submitted: 11/27/12; Revised: 01/26/13; Accepted: 02/07/ Human Vaccines & Immunotherapeutics 1049

3 Table 1. Approved therapeutic vaccines Formulation Product Company (Country) Cancer Status Completed/terminated phase III Result References Dendritic cell Provenge Dendreon Corp. (US) Prostate Approval (2010 US), Submission (2011 EU), III ongoing III D9901 F (Efficacy) 1 III D9902A F (Efficacy) 1 III D9902B, IMpacT S 30 Dendritic cell DCVax -Brain Northwest Biotherapeutics, Inc. (US) Glioblastoma Approval (2007 Switzerland), III ongoing Not completed NA 2 Downloaded by [ ] at 14:54 31 December 2017 Dendritic cell HybriCell Genoa Biotechnologia S.A. (Brazil) Tumor cell M-Vax TM Technologies, AVAX Inc. (US) Protein S, success; F, failure. CIMAVax EGF Oncophage (vitespen) Center of Molecular Immunology (Cuba) Agenus, Inc. (US) believe that approval of therapeutic vaccines is largely influenced by clinical evaluation. The objective of this study was to provide suggestions to improve clinical evaluation methods of therapeutic vaccines by reviewing historical cases and developmental trends of therapeutic vaccines in phase III studies. We believe the information obtained from our investigation will lead to an improvement in the development of therapeutic vaccines. Results Renal cell carcinoma, Melanoma Melanoma lung Renal cell carcinoma A total of 31 completed, discontinued, or on-going therapeutic vaccine projects were identified, which had 23 completed or terminated studies. Six approved projects had 5 completed or terminated studies (Table 1). Eleven discontinued projects, including 3 unknown projects, had 13 completed or terminated studies (Table 2). Fourteen on-going projects had 5 completed or terminated studies (Table 3). Therapeutic vaccine approvals. Approved therapeutic vaccines are listed in Table 1. Approval of therapeutic vaccines has not been limited to the US or the EU. Two cell formulation therapies, DCVax -Brain and M-Vax TM, were approved in Switzerland. HybriCell, Oncophage and CIMAVax EGF are approved for use in Brazil, Russia and Cuba and Peru, respectively. In contrast to the US and EU countries, phase III completion is often not required for approval in these countries. In fact, the study phase at the time of approval in these Approval (2005 Brazil) Approval (2005 Switzerland), Approval withdrawal (2002 Australia), III ongoing Approval (2008 Cuba, Peru), III ongoing Approval (2008 Russia), Submission failure (2009 EU) Not completed NA 3 III (immunopharmacology) NA 4, 8 Not completed Not applicable III C F (Efficacy) 5, 15 countries varied from phase I to phase III. Provenge is the only therapeutic vaccine to be approved based on phase IIIb data, which demonstrated significant efficacy of Provenge with regard to overall survival (OS). 19,30 In 4 cases (DCVax -Brain, HybriCell, M-Vax TM and CIMAVax EGF ), only early phase studies (phase I and II) were completed at the time of approval. Because Oncophage did not significantly affect efficacy in the primary endpoint, a withdrawal assessment report was issued by the EMA in However, Russia approved Oncophage in Results from phase III studies of therapeutic vaccines. Twenty-three completed or terminated phase III studies of therapeutic vaccines were included in our retrospective analysis. As shown in Tables 1, 2 and 3, only 17% (4/23) of the phase III studies were successful in demonstrating significant primary endpoint efficacy, whereas 74% (17/23) of the studies failed to do this. Only 1 phase III trial was unsuccessful because of patient safety, and 1 study did not aim to evaluate the efficacy or safety of therapeutic vaccines. Thus, demonstration of significant efficacy in the primary endpoint is a critical hurdle in the successful development of therapeutic vaccines. As shown in Table 1, most of the approved therapeutic vaccines are cell formulations [67% (4/6)]. Interestingly, most phase III studies in our analysis used peptide/protein formulations as opposed to cell formulations: in 30% (7/23), 9% (2/23) and 61% (14/23) of completed or terminated studies, the Human Vaccines & Immunotherapeutics Volume 9 Issue 5

4 Table 2. Discontinued therapeutic vaccines after Phase III study Formulation Product Company (Country) Cancer Status Completed/ Terminated Phase III Result References Downloaded by [ ] at 14:54 31 December 2017 Tumor cell canvaxin Amgen, Inc. (US) Melanoma Discontinued Gene PANVac TM -VF (falimarev) Therion Biologics Corp. (US) therapeutic vaccines were cell formulations, gene formulations and peptide/protein formulations, respectively. Successful phase III studies. Phase III studies of Provenge, G17DT immunogen (single agent), OncoVAX and BiovaxID showed significant efficacy in terms of primary endpoint. The primary endpoint of a pivotal phase III study (D9902B) of Provenge was changed after data from a supporting phase III study (D9901) were analyzed. This case of Provenge indicates that trial and error in the definition of the primary endpoint continues during phase III and that the results of a supporting concurrent phase III study may influence the design of other studies. With regard to the OncoVAX case, a phase IIIa study demonstrated the rationale for selecting the target study population as patients with Stage II colorectal for future phase III studies. This implies that the target study population could be identified from a pre-specified stratified population in 1 study. Provenge for prostate. Provenge is an autologous DC vaccine, activated against the using prostate-specific tumor antigens; hence, it is expected to stimulate the immune system against prostate. It targets prostatic acid phosphatase (PAP). Phase I/II: A phase I/II study was conducted to evaluate the safety, time to progression (TTP) and immune tolerance to PAP antigens. T-cell s to PAP were observed in 38% (10/26) of patients after treatment with Provenge. Anti-PAP antibodies did not exist at baseline, but 52% (16/31) of patients had detectable levels of antibodies after treatment. The median TTP was 34 Pancreatic III MMAIT-III F (Efficacy) 9 III MMAIT-IV F (Efficacy) 9 Discontinued III F (Efficacy) 10 Protein Theratope Oncothyreon Inc. (US) Breast Discontinued III F (Efficacy) 13 Stimuvax (BLP25) Oncothyreon, Inc. (US) Breast Discontinued III STRIDE F (Safety) 18 Protein S, success; F, failure. Specifid TM (mitumprotimut-t) MyVax GM2-KLH vaccine BEC2 Insegia TM (G17DT immunogen) OTS-102 Oncophage (vitespen) MMRGlobal, Inc. (US) Genitope Corp. (US) Progenics Pharmaceuticals, Inc. (US) Eli Lilly and Company (US) Receptor BioLogix, Inc. (US) OncoTherapy Science, Inc. (Japan) Non-Hodgkin lymphoma Non-Hodgkin lymphoma Discontinued III F (Efficacy) 20 Discontinued III F (Efficacy) 21 Melanoma Discontinued III F (Efficacy) 22 Small cell lung Pancreatic Pancreatic Discontinued III SILVA F (Efficacy) 23 Unknown III (single agent) S 12 III (combination) F (Efficacy) 12 Unknown II/III PEGasUS-pc F (Efficacy) 17 Agenus, Inc. (US) Melanoma Unknown III C F (Efficacy) 14 weeks for responders compared with 13 weeks for non-responders (p < 0.027). 43 Phase III: Three phase III studies on Provenge have been completed: D9901, D9902A and D9902B. The primary endpoint of D9901 and D9902A was not OS but TTP. In the D9901 study, the median OS was significantly higher in the Provenge arm (25.9 mo) than in the placebo arm (21.4 mo) [hazard ratio (HR) = 1.71; 95% confidence interval (CI), 1.13 to 2.58; p = 0.010]. 30,44 However, the method of OS analysis was not specified in advance, and the study could not prove the clinical benefit in terms of the primary endpoint. The median TTP was 11.7 weeks in the Provenge arm and 9.1 weeks in the placebo arm (HR = 1.45; 95% CI, 0.99 to 2.11; p = 0.052). In the D9902A study, both OS and TTP were not significantly different between the groups; the median OS was 19.0 mo in the Provenge arm and 15.7 mo in the placebo arm (HR = 1.27; 95% CI, 0.78 to 2.07; p = 0.331). 30 According to the FDA s regulatory history, after the analysis of OS in the D9901 study, the protocol of the D9902B study was amended to elevate OS as the primary endpoint. Originally, the primary endpoint was TTP and time to development of disease-related pain. Consequently, the median OS in the D9902B study was 25.8 mo in the Provenge arm and 21.7 mo in the placebo arm (HR = 0.78; 95% CI, 0.61 to 0.98; p = 0.03). 19 Data from the D9901 and D9902A studies were integrated, and a survival benefit was demonstrated (23.2 mo in the Provenge arm vs mo in the placebo arm; HR = 1.50; 95% CI, 1.10 to 2.05; p = 0.011), which became supportive evidence for the D9902B study Human Vaccines & Immunotherapeutics 1051

5 Table 3. Ongoing therapeutic vaccines in Phase III Formulation Product Company (Country) Cancer Status Completed/terminated phase III Result References Tumor cell OncoVAX Vaccinogen, Inc. (US) Colorectal III ongoing IIIa 8701 S 7 Tumor cell Lucanix NovaRx Corp. (US) lung Tumor cell Hyperacute- Pancreatic Cancer Vaccine (algenpantucel-l) NewLink Genetics Corp. (US) OncoVAX for colorectal. OncoVAX comprises autologous tumor cells and is used with Bacillus Calmette-Guerin (BCG) as an immunomodulating adjuvant. Immune to the tumor-specific antigens is expected following administration. Phase III: OncoVAX was evaluated in patients with Stage II or III colorectal in a phase IIIa study. The protocol specified separate analysis according to stage in advance. Significant efficacy was observed for Stage II colorectal. 7 The primary endpoint was recurrence-free survival (RFS): the 5-y RFS was 37.7% in the control arm and 21.3% in the OncoVAX arm (HR = 0.493; 95% CI to 0.897; p = 0.018). Although statistically significant efficacy was observed for Stage II cases, this was not observed for Stage III cases. According to the company s official website, Vaccinogen Inc. is conducting a phase IIIb study to evaluate disease-free survival as the primary endpoint in patients with Stage II colorectal. Reasons for phase III efficacy failure. Heterogeneity in the study population is a contributing factor to efficacy failure in phase III therapeutic vaccine trials (Table 4). Pancreatic Gene Allovectin-7 Vical Inc. (US) Melanoma III (high-dose) ongoing III (low-dose) F (Efficacy) 11 Gene ProstAtak TM Advantagene, Inc. (US) Prostate Protein astuprotimut-γ (MAGE-A3) GV1001 GlaxoSmithKline plc (UK) KaeL-GemVax Co., Ltd. (South Korea) Stimuvax (BLP25) Oncothyreon, Inc. (US) PR1 NeuVax MD Anderson Cancer Center Galena Biopharma, Inc. (US) lung Melanoma Pancreatic III ongoing III PriomoVax F (Efficacy) 16 lung lung III ongoing III START F (Efficacy) * Acute myeloid leukemia Breast pas Cancer Advances Inc. Pancreatic (US) GIST IMA901 Immatics biotechnologies GmbH (Germany) carcinoma Renal cell Biovest International, Non-Hodgkin BiovaxID Inc. (US) lymphoma III ongoing III S 24, 36, 37 racotumomab Racombio (Spain) lung S, success; F, failure; *Company homepage and / or ClinicalTrials.gov. Heterogeneity in the study population was mainly attributed to tumor stage and immunological. However, tumor burden was minimized in 69% (9/13) of the studies by surgery or induction drug therapy. Therapeutic vaccines were used postoperatively in 38% (5/13) of the studies. Thirty-one percent (4/13) of the studies include patients that responded to induction drug therapy before therapeutic vaccine therapy. Tumor stage. Some studies have reported the influence of tumor burden on the efficacy of therapeutic vaccines. For example, in PANVAC-VF, Madan et al. pointed out that for second-line therapy of metastatic pancreatic, tumor burden was a factor responsible for failure to meet the primary endpoint of OS. 38 On the other hand, 2 phase III studies of Oncophage reported that subset analysis according to tumor stage, as defined by the American Joint Committee on Cancer (AJCC), showed clinical benefit in patients with a better prognosis, although this benefit was not statistically significant. Oncophage for renal cell. Oncophage is a heatshock protein (glycoprotein 96)-peptide complex derived from 1052 Human Vaccines & Immunotherapeutics Volume 9 Issue 5

6 autologous tumors. 15 The gp96 peptide complex is taken up by DCs, resulting in T-cell stimulation. Phase II: A phase II trial in patients with metastatic renal cell carcinoma (RCC) was conducted to evaluate the TTP and rate (RR) of Oncophage, with or without the addition of interleukin-2 (IL-2). 40 The RR was 6.6% for Oncophage and 5.1% for Oncophage with IL-2. The median TTP was 65 d (95% CI, 62 to 88 d) for Oncophage and 168 d (95% CI, 122 to 233 d) for Oncophage with IL-2. Some trials on the use of IL-2 were conducted, and McDermott et al. reported that the rate was 23.2% for high-dose IL-2 vs. 9.9% for IL-2/interferon alfa-2b. 41 Thus, in phase II trials, Oncophage did not show the expected clinical benefit compared with the existing therapy. Phase III: A randomized, open-label, placebo-controlled phase III trial was conducted to determine the efficacy of Oncophage on the primary endpoint of RFS in patients with RCC. Patients with localized, resectable RCC and no evidence of distant metastases (n = 728) were randomized to receive Oncophage (n = 361) or observation only (n = 367). The number of recurrence events was 136 (37.7%) in the Oncophage arm and 146 (39.8%) in the observation arm (HR = 0.923; 95% CI, to 1.169; p = 0.506). 15 RFS was not significantly different between the Oncophage arm and the observation arm. However, subset analysis indicated that intermediate-risk patients in the Oncophage arm might show improvement in RFS and OS. Patients with stage I, II or III (T1, T2, T3a) tumors according to AJCC were included in the intermediate-risk subset. 15 These data were not sufficient for Oncophage approval by EMA. Patients with a better prognosis may have influenced the results of these studies. Oncophage for stage IV melanoma. Phase III: A randomized, open-label, placebo-controlled phase III trial was conducted to determine the efficacy of Oncophage on the primary endpoint of OS in patients with Stage IV melanoma. Patients (n = 322) were randomized to receive Oncophage (n = 215) or physician s choice (PC) (n = 107). OS was not significantly efficient between the Oncophage arm and the PC arm (HR = 1.16; 95% CI, 0.69 to 1.71; p = 0.32). 14 However, exploratory landmark analysis indicated that the combination of M1a and M1b (AJCC), but not M1c, substage patients showed a trend toward increased survival (HR = 0.45; 95% CI, 0.21 to 0.96; p = 0.03). 14 TM Specifid for non-hodgkin lymphoma. Specifid TM is a patientspecific Id-KLH therapeutic vaccine. The variable region of the immunoglobulin molecule of a B cell has a specific antigen-binding site. determinants are used to mimic antigens. Because the variable regions of immunoglobulins from tumor cells are different from those from normal cells, this vaccine is specific to tumors. Phase II: A phase II trial in patients with follicular B-cell lymphoma was conducted to evaluate event-free-survival (EFS), RR and safety of Specifid TM plus granulocyte-monocyte colonystimulating factor, following rituximab treatment. The RR was 60%, and the median EFS was 15.2 mo (95% CI, 11.6 to 20.2). The median EFS of previously untreated patients was 20.8 mo and that of relapsed patients was 13.5 mo. An anti-id humoral immune was observed in 20% (17/83) of evaluated patients. An anti-id cellular immune was observed in 72% (13/18) of evaluated patients. 32 According to Koc et al., published studies had indicated that the median EFS associated with single-agent rituximab therapy was 18 to 26 mo in previously untreated patients and 6 to 13 mo in relapsed patients. 32 Thus, Specifid TM was regarded as comparable with rituximab in a phase II study. Phase III: A randomized, blinded, placebo-controlled phase III trial was conducted to demonstrate the efficacy of Specifid TM on the primary endpoint of TTP in patients with follicular lymphoma. Eligible patients received rituximab for 4 weeks. Those showing stable disease (SD), partial (PR), or complete (CR) (n = 349) were assigned to the Specifid TM arm (n = 174) or the placebo arm (n = 175). The TTP was 9.0 mo in the Specifid TM arm and 12.6 mo in the placebo arm (HR = 1.384; 95% CI, to 1.819; p = 0.019). TTP was shorter in the Specifid TM arm than in the placebo arm. It was suggested that uneven distribution of the Follicular Lymphoma International Prognostic Index scores between the Specifid TM and placebo arms may have influenced the results. 20 Immunological. The humoral immune was evaluated using enzyme-linked immunosorbent assay (ELISA) in studies for Provenge, BEC2, Specifid TM, G17DT immunogen and MyVax. 12,19,23,42 Cellular immune was evaluated using a T-cell proliferation assay, intracellular cytokine staining (ICS), and enzyme-linked immunosorbent spot (ELISPOT) in studies for Provenge and MyVax, Specifid TM and PANVAC-VF, respectively. 19,42,32,46 Consequently, a correlation between immune and clinical was observed with BEC2 and G17DT immunogens. The survival of responders was better than that of non-responders in studies of both BEC2 and G17DT immunogens. BEC2 for small cell lung. BEC2 is an anti-idiotypic that mimics GD3, a ganglioside expressed on the tumor cell surface. Because GD3 is overexpressed in 60% of small cell lung (SCLC) tissues, a clinical anti-gd3 is expected to effectively treat SCLC. 23 Phase III: A randomized, placebo-controlled phase III trial was conducted to determine the efficacy of BEC2 on the primary endpoint of OS in patients with small cell lung (SCLC). Patients (n = 515) were assigned to the BEC2 arm (n = 257) or the observation arm (n = 258). The median OS was 16.4 mo in the BEC2 arm and 14.3 mo in the observation arm (HR = 1.12; 95% CI, 0.91 to 1.37; p = ). 23 OS and PFS were not significantly different between the 2 arms. Only one-third of patients that could be evaluated developed a humoral to GD3. However, survival was longer in responders than in nonresponders, but this difference was not statistically significant (19.2 mo for responders and 13.9 mo for non-responders; p = ). Although only 60% of SCLC tissues express GD3, GD3 expression was not evaluated or stratified in the study. 23 G17DT immunogen for pancreatic. Gastrin is a gastrointestinal hormone, and gastrin-stimulated tumors are detected in the pancreas and duodenum. G17DT immunogen is an antigastrin-17 immunogen that was developed to inhibit gastrin-stimulated tumor growth. Human Vaccines & Immunotherapeutics 1053

7 Table 4. Reasons of the Phase III failure to primary endpoint with therapeutic vaccine Product Cancer Treatment Position Regimen Immune Phase III subset analysis/consideration Suggested reasons of phase III failure References Oncophage Renal cell carcinoma (Stage I, II, III, IV) Post-surgical adjuvant 1st line Single agent NA Tumor stage: Subset analysis indicated that intermediate risk patients based on AJcc stage in Oncophage arm might improve RFS and OS. Recurrence events was 19 (15.2%) in stage I or II vs. 31 (27.0%) in observation group. (HR = 0.576; p = 0.056) (Tumor burden) 13, 15, 25 Oncophage Melanoma (Stage IV) Post-surgical adjuvant 1st line Single agent NA Tumor substage: Exploratory landmark analysis indicated that M1a and M1b, but not M1c, substage patients showed a trend toward increased survival. Combined data from M1a and M1b vs. control was HR = 0.45; 95% CI, 0.21 to 0.96; p = (Tumor metastasis) 14, 25 PANVac-VF Advanced pancreatic (Stage IV) 2nd line (Gemcitabine failure) GM-csF NA Study population: OS for 2nd line therapy of pancreatic is less than 3 mo. (Tumor burden) 13, 38 Canvaxin Melanoma (Stage III) Post-surgical adjuvant BCG NA Tumor substage: No stratified data available HLA expression: No stratified data available, though potential correlation between HLA and clinical benefit was identified. (Tumor burden, Immunological ) 9, 13 Canvaxin Melanoma (Stage IV) Post-surgical adjuvant BCG NA Tumor substage: No stratified data available HLA expression: No stratified data available (Tumor burden, Immunological ) 9, 13 GM2-KLH vaccine (GMK) Melanoma (Stage II) Post-surgical adjuvant QS21 NA NA Lack of adjuvant power 26 Theratope Metastatic breast 2nd line, CR/PR/SD to chemotherapy Pre-treatment with cyclophosphamide. Enhanzyn TM NA Concomitant therapy: Patients received concomitant hormonal therapy showed a trend toward longer OS and TTP. OS was longer in Theratope + hormone therapy and high IgG titers of anti-osm compared with low IgG titers. (41.1 vs mo; p = 0.01) (Concomitant therapy) 13, 39 Small cell lung BEC 2 2nd line, CR/PR to chemoradiotherapy BCG (Ph III) anti-gd3 (humoral: E) 33% Humoral to GD3: The survival of responders was better than that of nonresponders. (19.2 mo for responders and 13.9 mo for non-responders; p = ) (Immunological ) 13, 23, 33 Allovectin-7 Metastatic melanoma (Stage III, IV) 1st line combo. decarbazine NA NA Lack of dose (Low-dose) 11 NA, not applicable, includes not performed and unknown; E, enzyme-linked immunosorbent assay (ELIsa); I, intracellular cytokine staining (Ics); T, T cell proliferation assay Human Vaccines & Immunotherapeutics Volume 9 Issue 5

8 (continued) Table 4. Reasons of the Phase III failure to primary endpoint with therapeutic vaccine References Suggested reasons of phase III failure Phase III subset analysis/consideration Immune Product Cancer Treatment Position Regimen (Ph III) anti-g17 12 (Immunological ) Humoral to G17DT: Patients who developed an anti-g17dt had significantly improved survival compared with non-responders. (p = 0.003) Single agent Unsuitable or unwilling to chemotherapy Pancreatic (humoral: E) 73% Insegia TM (G17DT immunogen) 12 (Immunological ) NA Humoral reponse to G17DT: No data available gemcitabine 1st line combo. Pancreatic (Stage II, III, IV) (Ph II) anti-id 20, 21, 31, 32 (Tumor burden) Tumor stage: No stratified data available, though imbalance in FLIPI was identified. (humoral: E) 20% GM-csF CR/PR/SD to rituximab Non-Hodgkin Specifid TM lymphoma (WHO grade 1, 2, 3) (cellular: I) 72% (Ph I/II) anti-id (Immunological ) MyVax arm showed a statistically significant difference in PFS between patients who mounted a positive immune to the tumor-specific target and those who did not. (overall) 62% 21, 42, 47 GM-csF CR/PR to chemotherapy (CVP) Non-Hodgkin lymphoma (Stage III, IV) MyVax (humoral: E) 48% (cellular: T) 44% NA, not applicable, includes not performed and unknown; E, enzyme-linked immunosorbent assay (ELIsa); I, intracellular cytokine staining (Ics); T, T cell proliferation assay. Phase II: A phase II study in patients with pancreatic was conducted to evaluate, safety, tolerability and preliminary efficacy. 34 Of those patients receiving 100 μg or 250 μg, 67% (20/30) showed an to G17DT. The median OS of all participants was 187 d (95% CI, to ). The median OS of the responders was 217 d (95% CI, to 256.9), whereas that of the non-responders was 121 d (95% CI, 38.9 to 203.1). This difference was significant (p = ). Phase III: A randomized, double-blinded, placebo-controlled phase III trial was conducted to determine the efficacy of G17DT on the primary endpoint of OS in patients with advanced pancreatic. Patients (n = 154) were randomized to the G17DT arm (n = 79) or the placebo arm (n = 75). The median OS was 151 d in the G17DT arm and 82 d in the placebo arm (p < 0.03), indicating the improved OS in patients in the G17DT arm. In addition, patients who developed an anti-g17dt had significantly improved survival compared with non-responders (p = 0.003). 12 In contrast, a randomized, double-blinded, placebo-controlled phase III trial of G17DT in combination with gemcitabine in patients with advanced pancreatic failed to show any significant benefit with regard to the primary endpoint of OS. The OS was 178 d in the G17DT arm and 201 d in the placebo arm (HR = 1.19; p = 0.10). However, anti-g17 titer levels were associated with increased OS. 12,35 Discussion One of the reasons for the continued interest in the field of immunotherapy is the success of -based drugs, i.e., passive specific immunotherapy. Therapeutic vaccines are expected to have an impact on the immune system as active specific immunotherapy, resulting in better tolerability and efficacy compared with conventional treatment. However, for most therapeutic vaccines, clinical evidence of efficacy is still regarded as limited. Clinical evaluation methods for therapeutic vaccines continue to remain a challenge. Because of the therapeutic effect of vaccines on the host immune, traditional methods of determining drug efficacy are not applicable. 27 Our retrospective analysis showed that 74% (17/23) phase III studies on therapeutic vaccines failed to show a statistically significant effect of the vaccines on the primary endpoint. Studies have indicated that the use of tumor stage as the only prognostic factors in phase III trials is not sufficient. Immunological will help improve the probability of success in phase III trials by minimizing study population heterogeneity. Study population heterogeneity was a major factor contributing to the failure of therapeutic vaccines in phase III studies. For example, Specifid TM was regarded Human Vaccines & Immunotherapeutics 1055

9 as comparable with rituximab in a phase II study, despite the fact that TTP was shorter in the Specifid TM arm than in the placebo arm. As summarized by Dalgleish or Finke et al., promising results from phase I or II studies are not always reproducible in phase III studies. 13,26 One of the reasons for this is the population heterogeneity within a study. Inclusion criteria that are too broad or lack stratification may prevent the detection of significant efficacy s induced by therapeutic vaccines in phase III studies. Restriction of the patient population only to those for whom efficacy is predicted in advance, will improve the probability of success of these studies. Therefore, identification of prognostic factors for therapeutic vaccines is important for the future success of therapeutic vaccine development. Tumor stage categorization, whether determined according to AJCC or other methods of tumor scoring, is an important prognostic factor. For example, the OncoVAX phase III study, in which analysis was stratified according to tumor stage (Stage II and III), resulted in the identification of a favorable study population (Stage II) for further phase III studies. Some studies have suggested that tumor progression results in tumor-induced immunosuppression. 9,28 Therefore, if tumor burden is already high before therapeutic vaccine therapy, the immune stimulated by the vaccine may be reduced. Thus, tumor stage is a key consideration in study design. 9 Although most of the studies in our retrospective analysis based their eligibility criteria on the tumor stage (Table 3), they failed to show a significant effect in primary endpoint efficacy. Several studies have indicated that tumor substage according to tumor burden or metastasis may impact vaccine efficacy. 14,15 However, 69% (9/13) of the studies failed to demonstrate vaccine efficacy despite efforts to minimize tumor burden, including surgery and induction drug therapy, before therapeutic vaccine therapy. Some researchers have reported that certain chemotherapies, such as cyclophosphamide, deplete the regulatory T-cell population, which allows the proliferation of antigen-specific T cells. 45 Further, rituximab improves B-cell depletion, which may cause delayed induction of the humoral after vaccination. 21 These results suggest that minimal residual disease may not be the only prognostic factor for therapeutic vaccine efficacy. The characteristics of any pretreatment or combination drug should be taken into account when planning a study, because these may have an impact not only on the tumor burden but also on the immune system, which may result in patient heterogeneity in a study. Our retrospective analysis suggested that there may be room to consider immunological as an important prognostic factor for therapeutic vaccine efficacy. Currently, immune is not used often as a prognostic factor, but as a predictive factor. Our survey showed that ELISAs were predominantly used in the evaluation of the humoral immune in the studies examined. In contrast, assays for the assessment of the cellular immune were varied and included the T-cell proliferation assay, ICS and ELISPOT. Irrespective of the method used, the was defined as positive if the value exceeded the predefined threshold when compared with a baseline value. Further to these results, the correlation between the immune and clinical outcome becomes a target for discussion. Thus, currently, immune is mainly used as a surrogate marker to predict clinical outcome. However, immune is also expected to be a prognostic factor. Patient immune condition prior to treatment should be assessed to narrow down or stratify the patient population and reduce patient heterogeneity in a study. According to Galon et al., 29 a task force for immunoscoring was initiated as a new possible approach for the classification of by the Society of Immunotherapy of Cancer, the European Academy of Tumor Immunology, the Cancer and Inflammation Program, the National Cancer Institute, National Institute of Health and La Fondazione Melanoma. If immunological is able to predict the future efficacy of therapeutic vaccines with regard to the primary endpoint, it will be key to the success of phase III trials and provide scientific rationale for patient selection. Methods A retrospective analysis was performed using information obtained from ClinicalTrials.gov. and published articles. All clinical trials registered on ClinicalTrials.gov as of June 25, 2012, were searched using the following terms: condition, ; treatment, vaccine therapy ; and study type, interventional studies. Phase III studies that were completed, terminated or in progress were selected from the search results and therapeutic vaccine products were verified by manual review. Other phase III studies were also identified by literature searches via PubMed and company homepage. One product for 1 indication is defined as 1 project. Projects were categorized as approved, discontinued and ongoing, and are summarized in a table. Completed or terminated phase III studies were identified from the list to survey the reasons for study failure. Study results and product information were obtained from publically available articles. Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed. References 1. FDA s homepage Vaccines, Blood & Biologics, Cellular & Gene Therapy Products, Approved Products. Available from CellularGeneTherapyProducts/ApprovedProducts/ ucm htm 2. World s First Therapeutic Vaccine for Brain Cancer Commercially Available to Patients in Switzerland. Northwest Biotherapeutics, Inc. press release dated 9 July Brazilian Scientist creates one of the first commercially available vaccine against in the world. Genoa Biotechnologia S.A. News retrieved 25 October Melanoma Vaccine AVAX Technologies. Adis International Ltd. Biodrugs 2003; 17: Randazzo M, Terness P, Opelz G, Kleist C. Activespecific immunotherapy of human s with the heat shock protein Gp96-revisited. Int J Cancer 2012; 130: ; PMID: ; org/ /ijc González G, Lage A, Grombel T, Rodriguez G, Garcia B, Cuevas A, et al. CIMAvax-EGF: A novel therapeutic vaccine for advanced lung. Biotecnol Apl 2009; 26: Uyl-de Groot CA, Vermorken JB, Hanna MG Jr., Verboom P, Groot MT, Bonsel GJ, et al. Immunotherapy with autologous tumor cell-bcg vaccine in patients with colon : a prospective study of medical and economic benefits. Vaccine 2005; 23: ; PMID: ; org/ /j.vaccine Human Vaccines & Immunotherapeutics Volume 9 Issue 5

10 8. Berd D, Sato T, Maguire HC Jr., Kairys J, Mastrangelo MJ. Immunopharmacologic analysis of an autologous, hapten-modified human melanoma vaccine. J Clin Oncol 2004; 22:403-15; PMID: ; dx.doi.org/ /jco Sondak VK, Sabel MS, Mulé JJ. Allogeneic and autologous melanoma vaccines: where have we been and where are we going? Clin Cancer Res 2006; 12:2337s-41s; PMID: ; org/ / ccr Therion Reports Results of Phase 3 PANVAC-VF Trial and Announces Plans for Company Sale. PR Newswire 28 June available from com/news-releases/therion-reports-results-of-phase- 3-panvac-vf-trial-and-announces-plans-for-companysale html 11. Bedikian AY, Del Vecchio M. Allovectin-7 therapy in metastatic melanoma. Expert Opin Biol Ther 2008; 8:839-44; PMID: ; org/ / Gilliam AD, Watson SA. G17DT: an antigastrin immunogen for the treatment of gastrointestinal malignancy. Expert Opin Biol Ther 2007; 7: ; PMID: ; org/ / Finke LH, Wentworth K, Blumenstein B, Rudolph NS, Levitsky H, Hoos A. Lessons from randomized phase III studies with active immunotherapies--outcomes from the 2006 meeting of the Cancer Vaccine Consortium (CVC). Vaccine 2007; 25(Suppl 2):B97-109; PMID: ; vaccine Testori A, Richards J, Whitman E, Mann GB, Lutzky J, Camacho L, et al.; C Study Group. Phase III comparison of vitespen, an autologous tumor-derived heat shock protein gp96 peptide complex vaccine, with physician s choice of treatment for stage IV melanoma: the C Study Group. J Clin Oncol 2008; 26:955-62; PMID: ; org/ /jco Wood C, Srivastava P, Bukowski R, Lacombe L, Gorelov AI, Gorelov S, et al.; C RCC Study Group. An adjuvant autologous therapeutic vaccine (HSPPC-96; vitespen) versus observation alone for patients at high risk of recurrence after nephrectomy for renal cell carcinoma: a multicentre, open-label, randomised phase III trial. Lancet 2008; 372:145-54; PMID: ; Pharmexa stops one of two Phase III trials. Drugs.com May 13, 2008 available from news/pharmexa-stops-one-two-phase-iii-trials html 17. OncoTherapy Science, Inc. Press release dated Feb. 29, Oncothyreon announces temporary suspension of Stimuvax clinical trials by Merck Serono. Oncothyreon Inc. Press release dated Mar. 23, Kantoff PW, Higano CS, Shore ND, Berger ER, Small EJ, Penson DF, et al.; IMPACT Study Investigators. Sipuleucel-T immunotherapy for castration-resistant prostate. N Engl J Med 2010; 363:411-22; PMID: ; NEJMoa Freedman A, Neelapu SS, Nichols C, Robertson MJ, Djulbegovic B, Winter JN, et al. Placebo-controlled phase III trial of patient-specific immunotherapy with mitumprotimut-t and granulocyte-macrophage colony-stimulating factor after rituximab in patients with follicular lymphoma. J Clin Oncol 2009; 27: ; PMID: ; JCO Schuster SJ, Neelapu SS, Gause BL, Janik JE, Muggia FM, Gockerman JP, et al. Vaccination with patient-specific tumor-derived antigen in first remission improves disease-free survival in follicular lymphoma. J Clin Oncol 2011; 29: ; PMID: ; dx.doi.org/ /jco Fernandes LE, Gabri MR, Guthmann MD, Gomez RE, Gold S, Fainboim L, et al. NGcGM3 Ganglioside: a privileged target for vaccines. Clinical and Development Immunology 2010, Article ID814397, 8 pages doi: /2010/ Giaccone G, Debruyne C, Felip E, Chapman PB, Grant SC, Millward M, et al. Phase III study of adjuvant vaccination with Bec2/bacille Calmette-Guerin in responding patients with limited-disease small-cell lung (European Organisation for Research and Treatment of Cancer B; Silva Study). J Clin Oncol 2005; 23: ; PMID: ; Schuster SJ, Neelapu SS, Gause BL, Muggia FM, Gockerman JP, Sotomayor EM, et al. Idiotype accine therapy (BiovaxID) in follicular lymphoma in first complete remission: Phase III clinical trial results. J Clin Oncol 2009; 27:(suppl; abstr2). 25. Randazzo M, Terness P, Opelz G, Kleist C. Activespecific immunotherapy of human s with the heat shock protein Gp96-revisited. Int J Cancer 2012; 130: ; PMID: ; org/ /ijc Dalgleish AG. Therapeutic vaccines: why so few randomised phase III studies reflect the initial optimism of phase II studies. Vaccine 2011; 29:8501-5; PMID: ; Hoos A, Britten CM, Huber C, O Donnell-Tormey J. A methodological framework to enhance the clinical success of immunotherapy. Nat Biotechnol 2011; 29:867-70; PMID: ; org/ /nbt Hsueh EC, Morton DL. Antigen-based immunotherapy of melanoma: Canvaxin therapeutic polyvalent vaccine. Semin Cancer Biol 2003; 13:401-7; PMID: ; Galon J, Pagès F, Marincola FM, Thurin M, Trinchieri G, Fox BA, et al. The immune score as a new possible approach for the classification of. J Transl Med 2012; 10:1; PMID: ; org/ / Higano CS, Schellhammer PF, Small EJ, Burch PA, Nemunaitis J, Yuh L, et al. Integrated data from 2 randomized, double-blind, placebo-controlled, phase 3 trials of active cellular immunotherapy with sipuleucel- T in advanced prostate. Cancer 2009; 115:3670-9; PMID: ; cncr Redfern CH, Guthrie TH, Bessudo A, Densmore JJ, Holman PR, Janakiraman N, et al. Phase II trial of idiotype vaccination in previously treated patients with indolent non-hodgkin lymphoma resulting in durable clinical s. J Clin Oncol 2006; 24: ; PMID: ; JCO Koç ON, Redfern C, Wiernik PH, Rosenfelt F, Winter JN, Carter WD, et al. A phase 2 trial of immunotherapy with mitumprotimut-t (Id-KLH) and GM-CSF following rituximab in follicular B-cell lymphoma. J Immunother 2010; 33:178-84; PMID: ; Chapman PB, Williams L, Salibi N, Hwu WJ, Krown SE, Livingston PO. A phase II trial comparing five dose levels of BEC2 anti-idiotypic monoclonal vaccine that mimics GD3 ganglioside. Vaccine 2004; 22:2904-9; PMID: ; org/ /j.vaccine Brett BT, Smith SC, Bouvier CV, Michaeli D, Hochhauser D, Davidson BR, et al. Phase II study of anti-gastrin-17 antibodies, raised to G17DT, in advanced pancreatic. J Clin Oncol 2002; 20: ; PMID: ; org/ /jco Shapiro J, Marshall J, Karasek P, Figer A, Oette H, Couture F, et al. G17DT+gemcitabine [Gem] versus placebo+gem in untreated subjects with locally advanced, recurrent, or metastatic adenocarcinoma of the pancreas: Results of a randomized, double-blind, multinational, multicenter study. J Clin Oncol (ASCO Meeting Abstracts) 2005; 23(16S) Part I of II (June 1 Supplement). 36. Lee ST, Jiang YF, Park KU, Woo AF, Neelapu SS. BiovaxID: a personalized therapeutic vaccine for non-hodgkin lymphoma. Expert Opin Biol Ther 2007; 7:113-22; PMID: ; org/ / Shuster SJ, Neelapu SS, Gause BL, Muggia FM, Gockerman JP, Sotomayor EM, et al. Idiotype vaccine therapy (BiovaxID) in follicular lymphoma in first complete remission. ASCO2009 Annual Meeting. 38. Madan RA, Bilusic M, Heery C, Schlom J, Gulley JL. Clinical evaluation of TRICOM vector therapeutic vaccines. Semin Oncol 2012; 39: ; PMID: ; Mayordomo J, Tres A, Miles D, Finke L, Jenkins H. Long-term follow-up of patients concomitantly treated with hormone therapy in a prospective controlled randomized multicenter clinical study comparing STn- KLH vaccine with KLH control in stage IV breast following first line chemotherapy. [ASCO Meeting Abstracts]. J Clin Oncol 2004; 22(suppl 2603.). 40. Jonasch E, Wood C, Tamboli P, Pagliaro LC, Tu SM, Kim J, et al. Vaccination of metastatic renal cell carcinoma patients with autologous tumourderived vitespen vaccine: clinical findings. Br J Cancer 2008; 98: ; PMID: ; org/ /sj.bjc McDermott DF, Regan MM, Clark JI, Flaherty LE, Weiss GR, Logan TF, et al. Randomized phase III trial of high-dose interleukin-2 versus subcutaneous interleukin-2 and interferon in patients with metastatic renal cell carcinoma. J Clin Oncol 2005; 23:133-41; PMID: ; JCO Timmerman JM, Vose JM, Czerwinski DK, Weng WK, Ingolia D, Mayo M, et al. Tumor-specific recombinant idiotype immunisation after chemotherapy as initial treatment for follicular non-hodgkin lymphoma. Leuk Lymphoma 2009; 50:37-46; PMID: ; dx.doi.org/ / Small EJ, Fratesi P, Reese DM, Strang G, Laus R, Peshwa MV, et al. Immunotherapy of hormone-refractory prostate with antigen-loaded dendritic cells. J Clin Oncol 2000; 18: ; PMID: Small EJ, Schellhammer PF, Higano CS, Redfern CH, Nemunaitis JJ, Valone FH, et al. Placebo-controlled phase III trial of immunologic therapy with sipuleucel- T (APC8015) in patients with metastatic, asymptomatic hormone refractory prostate. J Clin Oncol 2006; 24: ; PMID: ; org/ /jco Terando AM, Faries MB, Morton DL. Vaccine therapy for melanoma: current status and future directions. Vaccine 2007; 25(Suppl 2):B4-16; PMID: ; Vergati M, Intrivici C, Huen NY, Schlom J, Tsang KY. Strategies for vaccine development. J Biomed Biotechnol 2010; 2010:596432; PMID: ; Genitope Corporation. Genitope Corporation To Suspend Development Of MyVax(R) Personalized Immunotherapy. Medical News Today. MediLexicon, Intl., 12 Mar Web. 10 Jan medicalnewstoday.com/releases/ php Human Vaccines & Immunotherapeutics 1057