A Phase II Study of Once Weekly Carfilzomib, Lenalidomide, Dexamethasone, and Isatuximab in Newly Diagnosed, Transplant-Eligible Multiple Myeloma

Background: Clinical data support the combination of a CD38 monoclonal antibody, an immunomodulatory drug, a proteasome inhibitor, and a glucocorticoid for the treatment of newly diagnosed multiple myeloma (NDMM). Recently, the GRIFFIN study evaluated the addition of the CD38 antibody, daratumumab to lenalidomide, bortezomib, and dexamethasone in transplant-eligible NDMM and demonstrated improved efficacy with an acceptable safety profile. Isatuximab is a newer CD38 monoclonal antibody that binds to a specific epitope of the CD38 receptor. In addition to antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis, and complement-dependent cytotoxicity, isatuximab eliminates MM cells via direct apoptosis without the need for crosslinking. Isatuximab enhances immune function by boosting the activation and cytotoxic activity of natural killer cells and by depleting CD38+ immune suppressor cells such as regulatory T cells and inducing clonal expansion of T cells. Isatuximab is approved in combination with carfilzomib and dexamethasone for relapsed, refractory MM based on the results of the IKEMA study. The MANHATTAN study evaluated the 4-drug combination of daratumumab, lenalidomide, carfilzomib, and dexamethasone. The primary end point, minimal residual disease negativity was achieved in 29 of 41 patients (71%; 95% CI, 54%-83%). Building upon these data, our study evaluates the addition of isatuximab to weekly carfilzomib, lenalidomide, and dexamethasone.

Study Design and Methods: A phase II, open-label clinical trial is being conducted to evaluate the efficacy of once weekly carfilzomib, lenalidomide, dexamethasone, and isatuximab (Isa-KRd) in 50 patients with newly diagnosed, transplant-eligible MM (NCT04430894). Eligible patients will have NDMM, age ≥18 years, ECOG PS of 0-2, and are deemed eligible for stem cell transplantation (SCT). All patients will receive 4 cycles of induction therapy with Isa-KRd followed by stem cell collection with the option to either proceed to upfront SCT versus deferred SCT. Patients undergoing upfront SCT will receive 4 cycles of therapy followed by stem cell collection, high-dose chemotherapy, and autologous SCT followed by 2 additional cycles of therapy then maintenance. Patients deferring SCT following collection will receive 4 cycles of therapy followed by stem cell collection followed by 4 additional cycles of therapy then maintenance. Each 28-day cycle will consist of isatuximab 10 mg/kg IV Q1 week for 8 weeks, then Q2 weeks for 16 weeks, thereafter Q4 weeks; carfilzomib (20 mg/m ² Day 1 only) 56 mg/m ² IV on Days 1, 8, 15; lenalidomide 25 mg po on Days 1-21; and dexamethasone 20 mg po day of and day after all doses of carfilzomib (Days 1, 2, 8, 9, 15, and 16) and isatuximab (Cycles 1 and 2 Days 22 and 23).

For maintenance, patients will be stratified based on cytogenetics (high-risk cytogenetics include deletion (del) 17p, translocation t(4:14), t(14;16), t(14;20)). Patients with standard-risk cytogenetics will receive lenalidomide 10 mg po Days 1-21. Patients with high-risk cytogenetics will receive carfilzomib 56 mg/m ² Days 1, 15; lenalidomide 10 mg po Days 1-21; and isatuximab 10 mg/kg IV Day 1. Dexamethasone, 20 mg orally or IV will be administered to patients as a pre-infusion medication prior to isatuximab dosing.

Main Outcomes and Measures: The primary end point is complete response (CR + stringent CR) rate after 4 cycles of Isa-KRd as assessed by the International Myeloma Working Group (IMWG) Uniform Response Criteria. Secondary endpoints include determining safety and tolerability of Isa-KRd, minimal residual disease (MRD) after 4 cycles, at completion of consolidation (post-transplant) or induction (transplant-deferred), and sustained MRD at 24 months, progression-free survival, overall survival rates, and quality of life.

Efficacy analysis will be performed both in the intent-to-treat (ITT) population and efficacy evaluable (EE) population. The ITT population will include all treated patients, and the EE population will include all patients who receive at least 1 cycle of study drug. The primary analysis will be based on the EE population, and will use the investigator-assessed response data evaluated according to consensus recommendations based on the IMWG criteria. CR (CR+sCR) rate after 4 cycles of Isa-KRd will be reported with 90% confidence interval.

Support: Amgen and Sanofi

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