Dr Popat on JNJ-5322 in Relapsed/Refractory Multiple Myeloma

“All patients [in the BCMA/GRPC5D–naive cohort] treated at the recommended phase 2 dose responded. The very good partial response rate was over 90%. [These were] very strong efficacy data.”

Rakesh Popat, MBBS, MRCP, FRCPath, PhD, a consultant hematologist at University College London Hospitals as well as the leader of the Myeloma Clinical Trials Program and the cancer program lead at the National Institute for Health Research University College London Hospitals Clinical Research Facility, discussed efficacy findings with the trispecific antibody JNJ-5322 in patients with relapsed/refractory multiple myeloma.

During the 2025 EHA Congress, Popat presented data from a phase 1 study (NCT05652335) examining JNJ-5322 in patients with triple-class exposed relapsed/refractory multiple myeloma. The study included patients who were exposed to BCMA/GRPC5D–directed therapies and those who had not received a prior BCMA/GRPC5D agent; most patients included in the study were BCMA/GRPC5D naive, Popat began.

At a median follow-up of 12.2 months, results from the trial demonstrated that efficacy-evaluable patients in the BCMA/GRPC5D–naive cohort who received JNJ-5322 at the recommended phase 2 dose (RP2D) of 100 mg every 4 weeks (n = 27) achieved an overall response rate (ORR) of 100%, Popat explained. The very good partial response (VGPR) rate was 96.3%, he added. Moreover, the complete response (CR) or better rate was 70.4%.

Efficacy-evaluable patients who received JNJ-5322 at doses of 50 mg to 300 mg in the BCMA/GRPC5D–exposed subgroup (n = 20) experienced an ORR of 55.0%, Popat noted. The CR or better rate among these patients was 30% and the VGPR rate was 50%.

In terms of durability of response, no patients in the BCMA/GRPC5D–naive cohort treated at the RP2D experienced disease progression, although 1 patient died due to an infection, Popat said. The 12-month progression-free survival rate in this group was 95.0%, he concluded.