Clinical Summary:

• Design/Population: Arm B of the phase 1b MOVISO study evaluated etentamig, a next-generation BCMA×CD3 bispecific T-cell engager, in 41 patients with relapsed or refractory multiple myeloma previously exposed to BCMA-directed therapy, including CAR T-cell therapy or antibody-drug conjugates. Patients were heavily pretreated, with a median of 6 prior lines of therapy and 81% triple-class refractory disease.
• Key Outcomes: Etentamig demonstrated meaningful and durable activity despite prior BCMA exposure, with the strongest responses observed in patients who received BCMA CAR T-cell therapy as their most recent treatment. Responses were deep, including MRD negativity in evaluable patients, and remained durable with clinically meaningful progression-free survival.
• Clinical Relevance: These findings suggest that etentamig may provide an effective treatment option following prior BCMA-directed therapy and support its development as a next-generation bispecific antibody with the potential for simplified monthly dosing and improved outpatient administration.

Saurabh Chhabra, MD, Mayo Clinic, Phoenix, Arizona, discusses results from the phase 1b MOVISO study evaluating etentamig in patients with relapsed or refractory multiple myeloma previously treated with BCMA-targeted therapies. As BCMA-directed therapies move earlier in the treatment paradigm, identifying effective sequential treatment strategies has become an increasingly important clinical challenge.

Etentamig produced durable responses in a heavily pretreated population, including patients whose disease had previously been exposed to CAR T-cell therapy or antibody-drug conjugates targeting BCMA. The study also demonstrated a favorable safety profile, with predominantly low-grade cytokine release syndrome despite administration without step-up dosing, supporting the potential for a more convenient monthly dosing strategy and broader outpatient use.

Dr Chhabra presented these results at the European Hematological Association (EHA) Annual Meeting in Stockholm, Sweden. 

Transcript:

Hi, my name is Saurabh Chhabra. I am a hematologist-oncologist and transplant and cell therapy physician at Mayo Clinic Arizona. I am also the associate director of the Blood and marrow transplant Program and section head of the myeloma program at Mayo Clinic Arizona. I’m honored to present the results of the MOVISO study, specifically Arm B, on behalf of my coinvestigators.

This is a phase Ib clinical trial investigating the use of a BCMA bispecific antibody called etentamig in relapsed/refractory multiple myeloma. Etentamig is a next-generation BCMA × CD3 bispecific T-cell engager composed of a bivalent BCMA-binding domain with a high-avidity, low-affinity CD3-binding domain that may reduce cytokine release syndrome. It also has a silenced Fc tail that extends its half-life and enables convenient once-monthly dosing. Arm B of the MOVISO study specifically evaluated etentamig in patients with prior BCMA exposure.

Eligible patients had relapsed or refractory multiple myeloma with at least 2 prior lines of therapy, including triple-class exposed disease and prior BCMA-directed therapy. Prior BCMA exposure could be in the form of a BCMA antibody-drug conjugate administered more than 30 days previously or a BCMA CAR T-cell therapy administered more than 6 months earlier. Patients received etentamig 60 mg intravenously on cycle 1 day 1 and every four weeks thereafter, notably without any step-up dosing.

At the June 2025 data cutoff, 41 BCMA-exposed patients had been treated, including 24 patients previously treated with BCMA CAR T-cell therapy and 17 patients previously treated with a BCMA antibody-drug conjugate. This was a heavily pretreated population, with a median of six prior lines of therapy. Eighty-one percent were triple-class refractory. Importantly, for approximately half of the patients, the most recent prior line of therapy was BCMA-directed. About 56% of patients had responded to their prior BCMA therapy, including 71% of those who had received CAR T-cell therapy and 35% of those who had received a BCMA ADC.

The median interval from prior BCMA therapy to etentamig treatment was approximately 15 months for patients who had received CAR T-cell therapy and 4 months for those who had received an ADC. Looking first at safety, despite the absence of step-up dosing, cytokine release syndrome occurred in 57% of patients. Importantly, all CRS events were grade 1 or 2. There were no high-grade CRS events. ICANS occurred in 7% of patients, with only one grade 3 event reported. Grade 3 or 4 neutropenia occurred in 36% of patients, and grade 3 or 4 infections occurred in 41%. No new safety signals were observed.

Looking at efficacy, etentamig demonstrated meaningful and durable activity despite prior BCMA exposure. Responses were particularly encouraging in patients who had received BCMA CAR T-cell therapy as their most recent prior line of treatment. In that group, response rates were higher than those observed in patients previously treated with BCMA ADCs, suggesting that etentamig may be particularly effective after prior CAR T-cell therapy. The responses observed were deep and durable. Among evaluable patients whose last prior therapy was BCMA-directed, MRD negativity at 10^-5 sensitivity was achieved in two of three evaluable patients.

The translational analyses also demonstrated robust activation and proliferation of CD8-positive T cells following treatment. Overall, the key message from Arm B is that despite prior BCMA exposure, etentamig was able to induce durable responses in a heavily pretreated patient population. Response rates appeared particularly favorable in patients who had received BCMA CAR T-cell therapy as their immediate prior treatment. From a safety perspective, no new concerns emerged, and importantly, only low-grade CRS was observed despite the absence of step-up dosing. 

These findings support the continued development of etentamig as a treatment option for patients with relapsed/refractory multiple myeloma who have previously received BCMA-directed therapies.

Source:

Chhabra S, Searle E, Popat R, et al. Etentamig in patients (pts) with relapsed/refractory multiple myeloma (RRMM) with prior exposure to B-cell maturation antigen (BCMA)-targeted therapy. Presented at EHA Congress. June 11 - June 14, 2026. Stockholm, Sweden. Abstract EHA-2799.