Despite new and novel treatments for patients with relapsed/refractory multiple myeloma (RRMM), patients who respond inadequately to 3 therapeutic classes (proteasome inhibitors, immunomodulators, and anti–CD-38 monoclonal antibodies) still have a poor prognosis. Studies have shown that B-cell maturation antigen (BCMA) expression is higher in patients with RRMM and may be associated with longer survival time of plasma cells.
Belantamab mafodotin (BM) is an anti-BCMA immunoconjugate that has demonstrated promising activity in the phase 1 DREAMM1 and phase 2 DREAMM2 trials in heavily pretreated patients with RRMM. These clinical trials often exclude specific patient populations, including elderly patients and those with comorbidities; therefore, an evaluation of real-world experience is needed to assess safety and efficacy among these groups. Shragai and colleagues presented updated results of real-world experience with BM monotherapy for RRMM via the GlaxoSmithKline expanded access compassionate care program.
In this analysis, 106 patients with RRMM were treated with BM from July 2019 to March 2021. Patients included in the analysis received ≥2 doses of BM under the expanded access program. The primary end point was progression-free survival (PFS), and secondary end points included overall response rate (ORR), overall survival (OS), and safety and tolerability.
After a median follow-up of 11.9 months, an average of 4 doses were administered. The ORR was 45%; 4% achieved a complete response, 14% had a very good partial response, and 27% achieved a partial response. The median PFS overall was 4.7 months (95% confidence interval [CI], 3.5-5.9), and it was 8.8 months (95% CI, 6.6-10.9) in patients achieving partial response or better. The median OS was 14.5 months (95% CI, 9.5-19.6).
In terms of safety, doses were delayed in 56% of patients; 27% of dose delays were due to ocular toxicity after the second dose. A total of 69% of patients experienced ocular toxicity; 12% were grade 1, 17% were grade 2, 40% were grade 3, and 1% were grade 4. In all, 3.8% of patients discontinued therapy due to adverse events, all of which were ocular, and 2 patients died because of treatment-related adverse events (pneumonia and sepsis). Other common adverse events (>10% of patients) included thrombocytopenia, infection, and anemia.
This study shows real-world favorable outcomes with BM monotherapy in patients with RRMM and supports its role in heavily pretreated patients.
Source
Shragai T, Magen H, Lavi N, et al. Real-world experience with belantamab mafodotin therapy for relapsed/refractory multiple myeloma: a multi-center retrospective study. Poster presented at: International Myeloma Foundation; August 25-27, 2022; Los Angeles, CA.