A real-world experience of efficacy and safety of belantamab mafodotin in relapsed refractory multiple myeloma.

While initial trials led to the accelerated approval of belantamab mafodotin, a BCMA-directed antibody-drug conjugate, confirmatory trials failed to establish benefit from this therapy for patients with relapsed refractory multiple myeloma (RRMM), eventually leading to its withdrawal from commercial use. With an imminent approval as an effective combination therapy, as seen in recent randomized trials, we report real-world clinical outcomes with belantamab mafodotin in 81 RRMM patients. With a median of 5 (range 2-15) prior lines of therapy, 92, 45, and 15% of the patients were triple-class refractory, penta-class refractory, and BCMA-refractory. More than half (57%) of the patients had high-risk cytogenetics, 37% had extramedullary disease (EMD), and 67% of the patients would have been considered ineligible for the DREAMM-2 trial. The best overall response (ORR) and complete response rates were 40.0 and 15.0%, respectively. ORRs were lower in patients with EMD, BCMA-refractory, and penta-refractory disease at 23, 17, and 24%, respectively. All-grade ocular toxicity was seen in 69% of patients, with grade 3+ events in 43%. Grade 3+ hematological toxicities included neutropenia (20%), anemia (28%), and thrombocytopenia (31%). With a median follow-up of 11.3 (0.3-44.6) months for the entire population, median PFS and OS were 5 (1-20) months and 12 (3-28) months, respectively. Presence of EMD was the only predictor of both PFS and OS on multivariable analysis. Compared to the pivotal trial and despite several high-risk disease features, belantamab mafodotin demonstrated comparable efficacy and safety in this real-world patient population.