ALBERT

Description: Introduction: Although outcomes for patients with multiple myeloma (MM) have improved with recent advances in treatment, relapse is still frequent. Early relapse is associated with poorer outcomes (Majithia et al., Leukemia 2016;30:2208-13) and is thought to reflect more aggressive disease, particularly within 12 months of autologous stem cell transplantation (ASCT). In the randomized phase 3 CANDOR study, progression-free survival (PFS) was significantly improved in patients with relapsed or refractory MM (RRMM) receiving carfilzomib, dexamethasone, and daratumumab (KdD) compared with carfilzomib and dexamethasone (Kd) (ClinicalTrials.gov, NCT03158688; Usmani et al., Blood 2019;134:LBA-6). In this post hoc analysis of the CANDOR study, we studied the safety and efficacy of KdD vs Kd in patients with early or late relapse following the most recent therapy. Methods: In the CANDOR study, patients with RRMM who received 1-3 prior lines of therapy were randomized 2:1 to receive KdD or Kd. The primary endpoint was PFS; secondary endpoints included overall response rate (ORR), rate of complete response or better (≥CR), and safety. In this analysis, subgroups were defined by relapse timing following the most recent therapy. Relapse

Description: Introduction: While minimal residual disease (MRD) negativity is not yet an established regulatory surrogate for a clinical endpoint in multiple myeloma (MM), it does have value as a prognostic biomarker and in assessing disease status. Previously we reported results from a phase 1b trial that described the safety and efficacy of the triplet regimen carfilzomib (given weekly), lenalidomide, and dexamethasone (KRd) in patients with relapsed and/or refractory MM (RRMM) or newly diagnosed MM (NDMM) (Biran et al, Am J Hematol 2019;94:794-802; Alsina et al, Clin Lymphoma Myeloma Leuk 2019;19:Suppl E52). Here, we evaluate MRD status by flow cytometry after treatment with weekly KRd in this trial. Methods: A total of 56 patients with RRMM and 51 with NDMM were enrolled and treated with weekly KRd. Treatment was given in 28-day cycles. Carfilzomib was given on days 1, 8, and 15; lenalidomide 25 mg on days 1-21; and dexamethasone 40 mg on days 1, 8, and 15 (also day 22 for cycle 1-8). In the NDMM cohort, patients were enrolled regardless of transplant eligibility, and treatment interruption for mobilization and collection with or without autologous stem cell transplant was allowed after cycle 4. Per the protocol, aspirate was collected for flow cytometry evaluation at two separate endpoints: at cycle 8 day 1 (C8D1); and at the time when laboratory data supported a response of complete response (CR) or better (on the basis of negative immunofixation on serum and urine). Sample quality was assessed by several measures (including the presence of mast cells, erythroid precursors, and immature B cells), and viability was determined using a flow assay. Adequate samples were tested for MRD using 8-color flow cytometry in two tubes, with a sensitivity of 10-5. MRD was reported as positive when a minimum of 2 x 106 CD138+ cells per tube were evaluated, and ≥ 20 abnormal events detected. Results: Overall, 58 of 79 (73.4%) study-specified samples were obtained and evaluated by flow cytometry. Of the NDMM patients, 15 had bone marrow aspirate evaluable for MRD at C8D1 (in total 22 patients were treated to C8D1), and 12 had bone marrow aspirate evaluable for MRD at the time of CR (14 patients achieved CR). At C8D1, 53% (8/15) of NDMM patients with flow data achieved MRD negativity, and at time of CR, 83% (10/12) of NDMM patients were MRD negative (the remaining patients with flow data were determined to be MRD positive). Among the 12 NDMM patients evaluated for MRD at time of CR, 17% had high-risk cytogenetics, 58% had standard-risk cytogenetics, and 25% had unknown cytogenetic risk status. Of the RRMM patients, 26 had bone marrow aspirate evaluable for MRD at C8D1 (30 patients were treated to C8D1), and five had bone marrow aspirate evaluable for MRD at the time of suspected CR or better (in total 13 patients achieved CR). Of RRMM patients with available flow data at time of CR, 40% (2/5) achieved MRD negativity, and of those with flow data at C8D1, 50% (13/26) achieved MRD negativity. Of all patient samples evaluated for MRD, 67% of NDMM and 48% of RRMM samples were MRD negative. The results reported here are directionally comparable to the rates of MRD-negative CRs observed in previous studies of twice-weekly KRd in NDMM (Jasielec J et al, Blood 2014;124:2127; Kazandjian D et al, JAMA Oncol 2018;4:1781-1783; Zimmerman T et al, Blood 2016;128:675). Our findings are limited by incomplete acquisition of samples to support a full MRD analysis per protocol (approximately 73% of the intended time point samples were acquired). Additionally, we reported MRD status without censoring for missing MRD data, as would be required to analyze MRD for a randomized controlled trial to eliminate acquisition bias. A robust comparison of MRD-negative CR rates between regimens would require an RCT with full MRD sampling, and sensitivity analyses that treat missing MRD data as MRD-positive (Chari A et al, Blood 2017;130:974-981; Voorhees PM et al, Blood 2020). Conclusions: We have previously shown that once-weekly KRd is active and has acceptable toxicity in both the RRMM and NDMM settings. We found that among MRD-evaluable patients who had a CR or better, MRD negativity rates were impressive in both the NDMM setting (83%) and in the RRMM setting (40%), suggesting that the weekly KRd regimen can induce MRD-negative CRs in both settings. Disclosures Landgren: Adaptive: Consultancy, Honoraria; Takeda: Other: Independent Data Monitoring Committees for clinical trials, Research Funding; Janssen: Consultancy, Honoraria, Other: Independent Data Monitoring Committees for clinical trials, Research Funding; Juno: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Independent Data Monitoring Committees for clinical trials, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria; Cellectis: Consultancy, Honoraria; Merck: Other; Cellectis: Consultancy, Honoraria; Binding Site: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Merck: Other; BMS: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Seattle Genetics: Research Funding; Glenmark: Consultancy, Honoraria, Research Funding; Binding Site: Consultancy, Honoraria; Karyopharma: Research Funding; Takeda: Other: Independent Data Monitoring Committees for clinical trials, Research Funding; Juno: Consultancy, Honoraria; Glenmark: Consultancy, Honoraria, Research Funding; Karyopharma: Research Funding; Seattle Genetics: Research Funding. Alsina:Janssen: Honoraria, Speakers Bureau; BMS: Consultancy, Research Funding; Celgene: Consultancy, Honoraria; Amgen: Honoraria, Speakers Bureau. Biran:Janssen: Consultancy, Honoraria, Other: reimbursement of travel and accomodation, Research Funding, Speakers Bureau; KAryopharma: Research Funding; Sanofi: Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Other: reimbursement of travel and accomodation, Research Funding, Speakers Bureau; BMS: Consultancy, Honoraria, Other: reimbursement of travel and accommodation, Research Funding, Speakers Bureau. Vesole:Amgen: Speakers Bureau; Takeda: Speakers Bureau; Sanofi: Speakers Bureau; Janssen: Speakers Bureau; BMS: Speakers Bureau. Fang:Amgen: Current Employment, Current equity holder in publicly-traded company. Arnold:Amgen: Current Employment, Current equity holder in publicly-traded company. Kimball:Amgen: Current Employment, Current equity holder in publicly-traded company; WindMIL Therapeutics: Current equity holder in private company. Siegel:Karyopharma: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Celulatiry: Consultancy. OffLabel Disclosure: Carfilzomib is a proteasome inhibitor that can be used for the treatment of relapses/refractory multiple myeloma