Long-term ixazomib maintenance is tolerable and improves depth of response following ixazomiblenalidomide-dexamethasone induction in patients with previously untreated multiple myeloma (MM): Phase 2 study results Shaji K. Kumar, 1 Jesus G. Berdeja, 2 Ruben Niesvizky, 3 Sagar Lonial, 4 Jacob P. Laubach, 5 Mehdi Hamadani, 6 A. Keith Stewart, 7 Parameswaran N. Hari, 8 Vivek Roy, 9 Robert Vescio, 10 Jonathan L. Kaufman, 4 Deborah Berg, 11 Eileen Liao, 11 Ai-Min Hui, 11 S. Vincent Rajkumar, 1 Paul G. Richardson 5 1 Division of Hematology, Mayo Clinic, Rochester, MN; 2 Sarah Cannon Research Institute, Nashville, TN; 3 Myeloma Center, Weill Cornell Medical College, New York Presbyterian Hospital, New York, NY; 4 Winship Cancer Institute of Emory University, Atlanta, GA; 5 Dana-Farber Cancer Institute, Boston, MA; 6 West Virginia University, Mary Babb Randolph Cancer Center, Morgantown, WV; 7 Hematology/Oncology, Mayo Clinic, Scottsdale, AZ; 8 Division of Hematology Oncology, Medical College of Wisconsin, Milwaukee, WI; 9 Hematology- Oncology, Mayo Clinic, Jacksonville, FL; 10 Cedars-Sinai Outpatient Cancer Center at the Samuel Oschin Comprehensive Cancer Institute, Los Angeles, CA; 11 Takeda Pharmaceuticals International Co., Cambridge, MA
Ixazomib Ixazomib is an investigational, oral, reversible, and specific 20S proteasome inhibitor The first oral proteasome inhibitor in clinical development Physiochemical properties distinct from bortezomib 1 Ixazomib has been evaluated in single-agent and combination studies in MM Clinical activity of single-agent ixazomib seen in heavily pretreated patients 2,3 Data suggest a manageable toxicity profile with low rates of peripheral neuropathy (PN) 2,3 Phase 3 trials underway 1. Kupperman E, et al. Cancer Res 2010;70:1970 80. 2. Richardson PG, et al. Blood 2014;124:1038 46. 3. Kumar SK, et al. Blood 2014;124:1047 55.
Rationale Triplet regimens combining a proteasome inhibitor, an immunomodulatory drug, and a steroid shown to be active and well tolerated in previously untreated MM patients 1 3 High response rates seen with the bortezomib, lenalidomide, dexamethasone (VRD/RVD) regimen 1,2 Increasing evidence suggests that extended treatment may add benefits to conventional induction strategies Long-term maintenance therapy improves survival outcomes, including PFS and sometimes OS, in both the transplant and non-transplant settings However, agents for continuous therapy need to be convenient and well tolerated Oral weekly ixazomib may be an ideal maintenance drug in terms of tolerability/safety and convenience 1. Kumar S, et al. Blood 2012;119:4375 82. 2. Richardson PG, et al. Blood 2010;116:679 86. 3. Jakubowiak AJ, et al. Blood 2012;120:1801 9.
Phase 1/2 study of weekly ixazomib plus lenalidomide-dexamethasone (NCT01217957) Triplet regimen investigated in an open-label, dose-escalation, phase 1/2 study, conducted in patients with previously untreated MM to: Define the dose of ixazomib to be combined with lenalidomide and dexamethasone Evaluate the efficacy and toxicity of the combination Evaluate the feasibility, efficacy, and safety of long-term maintenance therapy with single-agent ixazomib The recommended phase 2 dose (RP2D) was determined to be ixazomib 4.0 mg weekly, on days 1, 8, 15, with lenalidomide 25 mg on days 1 21, and dexamethasone weekly, in 4-week cycles 1 Results of induction therapy have been previously reported 1 Here we report phase 2 efficacy and safety data in patients receiving ixazomib maintenance 1. Kumar SK, et al. Lancet Oncol 2014;15:1503 12.
Patient eligibility Key inclusion criteria: Age 18 years ECOG performance status 0 2 Adequate hepatic, renal, and hematologic function Measurable disease: Serum M-protein 1 g/dl Urine M-protein 200 mg/24 hours Involved free light chain 10 mg/dl Key exclusion criteria: Grade 2 PN Prior/concurrent deep vein thrombosis/pulmonary embolism Prior systemic MM therapy
Study design Phase 2 dosing Induction: up to 12 x 28-day treatment cycles 1 8 15 22 28 Maintenance Ixazomib 4.0 mg Ixazomib 4.0 mg Ixazomib 4.0 mg Dex 40 mg Dex 40 mg Dex 40 mg Dex 40 mg Lenalidomide 25 mg, days 1 21 Ixazomib maintenance Days 1, 8, 15 28-day cycles Mandatory thromboembolism prophylaxis with aspirin 81 325 mg QD or lowmolecular-weight heparin while receiving lenalidomide dexamethasone Stem cell collection allowed after 3 cycles; patients could proceed to ASCT after 6 cycles Ixazomib maintenance continued until progression or unacceptable toxicity Ixazomib administered at last tolerated dose during induction Primary objective was CR+VGPR rate
Enrollment and disposition 65 patients enrolled 1 15 Phase 1, 50 Phase 2 Median no. of cycles: 7 (range 1 45) 17 patients off treatment before cycle 13 (maintenance) 2 Phase 1 patients Both due to AEs 15 Phase 2 patients 6 due to AEs 4 patient withdrawals 2 disease progression 1 unsatisfactory response 2 other 23 withdrew to initiate ASCT 9 Phase 1, 14 Phase 2 25 patients entered maintenance phase 4 Phase 1 patients (BSA-based dosing) Received actual doses of 4.0, 4.0, 3.6, and 3.4 mg 21 Phase 2 patients (fixed dosing 2 ) 16 entered at 4.0 mg 4 entered at 3.0 mg 1 entered at 2.4 mg Focus of the current presentation 1. Kumar SK, et al. Lancet Oncol 2014;15:1503 12. 2. Gupta N, et al. Br J Clin Pharmacol 2014;doi: 10.1111/bcp.12542
Patient characteristics All phase 2 patients, n=50 Patients receiving maintenance, n=21 Median age, years (range) 65 (34 86) 68 (34 77) Age 65 years, n (%) 25 (50) 12 (57) Age 75 years, n (%) 9 (18) 2 (10) Male, n (%) 30 (60) 13 (62) White, n (%) 42 (84) 16 (76) ISS disease stage at diagnosis, n (%) I 25 (50) 14 (67) II 19 (38) 7 (33) III 6 (12) 0 MM subtype, n (%) IgG 34 (68) 16 (76) IgA 9 (18) 3 (14) IgD 1 (2) 0 Light chain 6 (12) 2 (10) Median creatinine clearance, ml/min 85.3 83.5
Cytogenetics All phase 2 patients, n=50 Patients receiving maintenance, n=21 Patients with cytogenetic assessment, N* 47 19 Conventional/karyotype 7 (15) 3 (16) Molecular/FISH 15 (32) 6 (32) Both 25 (53) 10 (53) Unfavorable cytogenetics, n (%) 6 (13) 3 (16) Type of cytogenetic abnormality, n (%) del 13 (by metaphase cytogenetics) 2 (4) 2 (11) del 17 2 (4) 1 (5) t(4;14) 1 (2) 0 t(14;16) 1 (2) 1 (5) 1q amplification 1 (2) 0 *No sample collected for 3 patients. Unfavorable cytogenetics includes del 17, t(4;14), t(14;16), and 1q amplification abnormalities detected by FISH or metaphase cytogenetics and del 13 detected by metaphase cytogenetics.
Treatment exposure At data cut-off (October 2, 2014) Median cycles of ixazomib received, n (range) Patients receiving maintenance, n=21 Total (including induction and maintenance cycles) 31 (15 35) Maintenance cycles 19 (3 23) Median treatment duration, months (range) 29.0 (16.3 33.3) Maintenance duration, months (range) 19.8 (2.3 22.9) Mean relative dose intensity* of ixazomib overall / during induction / during maintenance, % 92 / 95 / 89.5 Patients remaining on ixazomib maintenance, n (%) 11 (52%) *Dose taken/dose prescribed Among the 29 patients in phase 2 who did not proceed to maintenance, median number of cycles of ixazomib received was 6 (1 12) Median cycle of first stem cell mobilization (n=14) was cycle 4 (3 9), and patients who received ASCT received a median of 6 (3 12) cycles of ixazomib
Best response to treatment, all patients (n=49)* 100% All patients, n=49* 90% 16 Best response, n (%) To induction Overall 80% 70% 19 scr CR+VGPR+PR 44 (90) 44 (90) CR 11 (22) 17 (35) 60% 50% 40% 30% 20% 10% 0% 8 16 31 6 4 Best response overall CR ncr VGPR PR MR SD scr 5 (10) 8 (16) VGPR 18 (37) 12 (24) ncr 2 (4) 4 (8) CR+VGPR 29 (59) 29 (59) PR 15 (31) 15 (31) MR 3 (6) 3 (6) SD 2 (4) 2 (4) *1 patient in phase 2 not response-evaluable Among the 14 patients who discontinued induction to undergo ASCT, best response to induction included 4 (29%) scr, 4 (29%) VGPR, and 6 (43%) PR Response following ASCT are not included in the above data
Best response to treatment in phase 2 patients receiving maintenance (n=21) 100% 90% 80% 5 19 n=2 n=1 19 70% 60% 50% 40% 30% 48 n=5 n=2 33 10 10 scr CR ncr VGPR PR MR SD 20% 10% 29 29 0% Best response to induction Best response overall 10 (48%) patients improved their response during maintenance: 2 VGPR to ncr, 5 VGPR to CR, 1 VGPR to scr, and 2 CR to scr
Progression-free survival probability PFS 1.0 0.8 Phase 2 patients who received maintenance All phase 2 patients (patients who proceeded to ASCT [n=14] were censored at last response assessment before ASCT) 0.6 0.4 0.2 0 0 Median follow-up among censored phase 2 patients who received maintenance (n=21): 31.2 months 10 patients have progressed; median PFS not reached Estimated percentage of patients surviving without progression at 2 years: 57% Median PFS among all phase 2 patients (n=50): 28.7 months Estimated percentage of patients surviving without progression at 2 years: 50% 3 Number of patients at risk: 50 49 21 21 6 40 21 9 30 21 12 Time to event (months) 26 21 15 20 17 18 16 14 21 15 13 24 12 10 27 11 9 30 7 7 33 0 0 All 21 patients who received ixazomib maintenance were alive after follow-up of 25.1 33.9 months, including a median follow-up from start of maintenance of 19.9 months (range 13.4 22.2)
Most common drug-related AEs (>20% patients overall, or with new onset in >1 patient during maintenance) Any AE Skin and SC tissue disorders Diarrhea Fatigue Nausea Peripheral neuropathies NEC Constipation Insomnia Vomiting Dysgeusia Abdominal distension Malaise Muscle spasms Anemia Thrombocytopenia Hypokalemia Pain in extremity Headache Overall During induction During maintenance 0 10 20 30 40 50 60 70 80 90 100 Patients, % NEC, not elsewhere classified
Grade 3 drug-related AEs, overall and by treatment phase Fatigue Skin and SC tissue disorders Thrombocytopenia Hypokalemia Hypophosphatemia Neutropenia Abdominal distension Anemia Cataract Decreased appetite GE reflux disease Intestinal perforation Lymphopenia Neutrophil count decreased Non-cardiac chest pain Overall During induction During maintenance 0 5 10 15 20 25 Patients, % GE, gastro-esophageal Drug-related grade 3 AEs were reported in 13 (62%) patients overall, including in 11 (52%) during induction and in 3 (14%) patients during maintenance There were no grade 4 drug-related AEs reported at any time during induction and maintenance among the 21 patients who received ixazomib maintenance
Serious AEs (SAEs) and dose reductions Of the 21 patients who received maintenance therapy, 10 (48%) reported an SAE at any time during induction and maintenance treatment Including 3 (14%) with drug-related SAEs SAEs were reported in 4 (19%) patients during ixazomib maintenance: Grade 3 acute myocardial infarction; grade 3 pneumonia; grade 3 orthostatic hypotension; grade 2 ventricular extrasystoles All were considered not related to treatment In total, 17 (81%) patients required any study drug dose reduction due to an AE during induction Only 2 (10%) patients required ixazomib dose reduction during maintenance, due to PN and neuralgia, respectively There were no discontinuations due to AEs and no on-study deaths
Conclusions The all-oral combination of ixazomib, lenalidomide, and dexamethasone is active as induction therapy, with a manageable safety profile, at the RP2D in previously untreated MM patients 90% of patients achieved PR or better, including a VGPR rate of 59% and a CR rate of 22%, after up to 12 cycles of induction Common AEs included skin and SC tissue disorders, diarrhea, fatigue, nausea, and peripheral neuropathy Data on 21 patients who received maintenance therapy indicate that single-agent ixazomib maintenance for up to 1.9 years was feasible, with a generally manageable safety profile, in patients not undergoing ASCT Ixazomib maintenance improved responses following triplet induction therapy, with 48% of patients showing increased response depth during maintenance Rate of CR+nCR increased from 24% after induction to 62%, with 71% VGPR Ixazomib maintenance contributed to durable responses New-onset toxicity during single-agent ixazomib maintenance was limited A phase 3 trial of ixazomib plus lenalidomide dexamethasone versus placebo plus lenalidomide dexamethasone in patients with previously untreated MM is currently enrolling (TOURMALINE-MM2; NCT01850524)
Acknowledgments We thank all the patients and their families who participated in this study We also thank the physicians, research nurses, study coordinators, and research staff involved in the study We acknowledge Steve Hill of FireKite, part of KnowledgePoint360, an Ashfield company, for writing assistance during the development of this presentation, which was funded by Takeda Pharmaceuticals International Co.