Belantamab mafodotin in patients with relapsed/refractory multiple myeloma: a real-world experience

Belantamab mafodotin is an antibody-drug conjugate targeting B-cell maturation antigen (BCMA) for the treatment of multiple myeloma. To evaluate the efficacy and safety of belantamab mafodotin in a real-world setting in the United States, we assessed all patients treated with commercial belantamab mafodotin at the Memorial Sloan Kettering Cancer Center between 2020 and 2023. Ninety-four patients were identified; 57 had high-risk cytogenetics, 77 were triple-class refractory, the median prior lines of therapy was 6, and 18 patients had received prior BCMA-targeted treatment. The overall response rate (ORR) was 43%, and 21% achieved a very good partial response or better. The median progression-free survival (PFS) was 3.8 months, median overall survival (OS) was 17.2 months, and the median duration of response was 10.5 months. In patients with prior BCMA exposure (median prior lines of therapy = 9), the ORR was 29%, PFS was 2 months, and OS was 20.4 months. Sixty-one patients (65%) had any grade of ocular toxicity and 15 patients had grade 3 or more keratopathy. All keratopathy was reversible and resolved or reduced to grade 1 by the end of the follow-up. Most patients could continue on a reduced dose or with a longer dose interval while maintaining the clinical response. Eighteen patients had 1 or more infections, most of which were grade 1/2. In summary, belantamab mafodotin showed significant ORR, including those of patients with prior BCMA exposure. Ocular toxicity was similar to that in previous reports, and the risk of serious infections was low in this cohort of heavily pretreated patients with multiple myeloma.