Real-world outcomes in relapsed refractory multiple myeloma patients exposed to three or more prior treatments: an analysis from the ANZ myeloma and related diseases registry

Abstract

Background: There is no currently available standard of care for triple-class exposed, relapsed refractory myeloma (RRMM) patients in Australia. CARTITUDE-1 (CART-1) was a single-arm, phase 1b/2 study of 97 triple-class exposed RRMM patients, who received BCMA-CAR-T cell therapy with ciltacabtagene autocel. Overall response rate (ORR) was 98%. Median progression free survival (PFS) and overall survival (OS) had not been reached at a median follow-up of 28 months.

Methods: We performed a retrospective analysis on a cohort of CART-1 comparable RRMM patients participating in the Australian and New Zealand Myeloma and Related Diseases Registry (MRDR), to compare outcomes in triple-class exposed MM patients treated with currently available therapies, in a real-world context. The CE-MRDR cohort (n = 28) fulfilled CARTITUDE-1 eligibility (CE) criteria: ≥3 lines of therapy (LOT) including an immunomodulatory agent, proteasome inhibitor and CD38-directed monoclonal antibody (CD38mAb) and Eastern Cooperative Oncology Group Performance Status (ECOG PS) score of 0-2 at diagnosis. The modified-CE-MRDR (n = 132) received ≥3 LOT but may not have received a CD38mAb with an ECOG PS score of 3 (0-3).

Results: Responses to the first subsequent therapy after eligibility were poor - ORR was 23% and 0% with progressive disease (PD) reported in 61% and 36%, CE-MRDR and m-CE-MRDR respectively. Responses to the second subsequent therapy after eligibility were worse, ORR 0% and 31%, CE-MRDR and m-CE-MRDR respectively, with high rates of PD, particularly in CE-MRDR. Median OS was 5.4 versus 9.5 months, CE-MRDR versus m-CE-MRDR.

Conclusions: This retrospective analysis confirms uniformly poor outcomes for Australian RRMM patients. There remains a critical need for greater accessibility to novel treatments, such as CAR-T, outside clinical trials.