Belantamab mafodotin, an investigational anti-B-cell maturation antigen monoclonal antibody-drug conjugate, demonstrated anti-myeloma activity in patients with relapsed/refractory multiple myeloma (MM), according to a study published in The Lancet Oncology.
The open-label, two-arm, randomized, phase II, ongoing DREAMM-2 study was conducted at 58 MM specialty centers in eight countries and included adult patients with relapsed/refractory MM that had progressed after three or more lines of therapy and who were refractory to immunomodulatory drugs and proteasome inhibitors and refractory and/or intolerant to an anti-CD38 monoclonal antibody. Patients had an Eastern Cooperative Oncology Group performance status score of 0-2 and were stratified based on prior lines of therapy (≤4 vs. >4) and cytogenetic features.
Between June 18, 2018, and Jan 2, 2019, 293 patients were randomized 1:1 to receive belantamab mafodotin 2.5 mg/kg (n=97) or 3.4 mg/kg (n=99) intravenously every three weeks on day one of each cycle until disease progression or unacceptable toxicity.
Response observed in approximately one-third of patients
At primary analysis cutoff (June 21, 2019), 30 patients (31%; median age, 65 years) in the 2.5 mg/kg cohort and 34 patients (34%; median age, 67 years) in the 3.4 mg/kg cohort achieved an overall response (primary endpoint). Median duration of response was not yet reached at a median follow-up of 6.3 months in the 2.5 mg/kg group and 6.9 months (IQR, 4.8-7.9) in the 3.4 mg/kg group.
Overall survival data were not mature at the time of analysis. The median progression-free survival was 2.9 months in the 2.5 mg/kg group and 4.9 months in the 3.4 mg/kg group.
The most common grade 3/4 adverse events (AEs) associated with belantamab mafodotin 2.5 mg/kg and 3.4 mg/kg included keratopathy (27% vs. 21%), thrombocytopenia (20% vs. 33%), and anemia (20% vs. 25%). Serious AEs occurred in 38 patients (40%) in the 2.5 mg/kg cohort and 47 patients (47%) in the 3.4 mg/kg cohort.
A total of 32 deaths occurred in the 2.5 mg/kg group and 31 deaths occurred in the 3.4 mg/kg group. Two deaths were potentially related to treatment: sepsis in the 2.5 mg/kg cohort and hemophagocytic lymphohistiocytosis in the 3.4 mg/kg cohort.