MagnetisMM-30: A phase 1b, open-label study of elranatamab in combination with iberdomide in patients with relapsed or refractory multiple myeloma (RRMM).

Abstract

TPS7577 Background: Elranatamab (ELRA) is a humanized B-cell maturation antigen (BCMA)–CD3 bispecific antibody (BsAb). Single-agent ELRA induced deep and durable responses with a manageable safety profile in patients (pts) with RRMM enrolled in the phase 2 registrational MagnetisMM-3 study (NCT04649359; Lesokhin et al, Nat Med 2023). Iberdomide (IBER) is a novel CELMoD[TM] agent that induces enhanced antimyeloma tumoricidal and immunomodulatory activity in pts with RRMM (Lonial et al, Lancet Haematol 2022). While IBER in combination with ELRA has not been evaluated clinically, it may provide additional benefit to pts with RRMM based on the mechanisms of action of this novel combination. Methods: MagnetisMM-30 is a phase 1b, open-label, prospective study evaluating the safety, efficacy, and pharmacokinetics of ELRA in combination with IBER in pts with RRMM. The study has 2 parts: Part 1 for dose-escalation and Part 2, randomized for dose optimization. After 2 step-up priming doses of ELRA, pts will receive subcutaneous ELRA weekly with IBER given daily for 21 days of each 28-day cycle. After ≥6 months (cycles) of treatment, pts with a partial response or better for ≥2 months are eligible for reduced dosing frequency of ELRA. Once the 2 combination dose levels (dose levels A and B) are selected from Part 1 as the recommended phase 2 doses for ELRA and IBER, pts in Part 2 will be randomized 1:1 (stratified by the number of prior lines of therapy [LOTs; 1 vs >1]) to dose levels A and B. Key inclusion criteria are pts aged ≥18 years with a MM diagnosis per IMWG criteria, Eastern Cooperative Oncology Group performance status of 0-1, adequate organ and bone marrow function, and disease relapsed or refractory to the last antimyeloma regimen per IMWG response criteria. Pts who received 2-4 or 1-3 prior LOTs, including ≥1 immunomodulatory drug (IMiD) and ≥1 proteasome inhibitor (PI), are eligible for Parts 1 and 2, respectively. All pts must have received ≥2 consecutive cycles of an IMiD-containing regimen and ≥2 consecutive cycles of a PI or PI-containing regimen. Key exclusion criteria are pts with stem cell transplant ≤12 weeks prior to enrollment; active, uncontrolled infection; prior treatment with BCMA-directed or CD3 redirecting therapy or prior CELMoD agents (ie, IBER or mezigdomide). This study is ongoing; Part 1 and Part 2 will enroll approximately 27 and 60 pts, respectively. Study endpoints are listed in the table. Clinical trial information: NCT06215118 . [Table: see text]