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Longer-Term Outcomes with Single-Agent Belantamab Mafodotin in Patients with RRMM: 13-Month Follow-Up from the Pivotal DREAMM-2 Study

2021 Year in Review - Multiple Myeloma

Longer-term data from the DREAMM-2 trial confirmed the sustained clinical activity of the anti–B-cell maturation antigen antibody–drug conjugate belantamab mafodotin in heavily pretreated patients with RRMM, with no emergence of new safety signals.

The ongoing, phase 2, open-label, 2-arm DREAMM-2 study (NCT03525678) evaluated the anti–B-cell maturation antigen antibody–drug conjugate belantamab mafodotin monotherapy in patients with relapsed/refractory multiple myeloma (RRMM). The 13-month follow-up efficacy and safety outcomes of the DREAMM-2 trial in patients who received belantamab mafodotin 2.5 mg/kg were published in the November issue of Cancer and summarized here.

The DREAMM-2 study enrolled patients with RRMM who had disease progression after ≥3 lines of therapy and were refractory to immunomodulatory drugs and proteasome inhibitors and refractory and/or intolerant to an anti-CD38 therapy. Eligible patients received 2 doses of belantamab mafodotin (2.5 mg/kg or 3.4 mg/kg). The primary end point was overall response rate, as assessed by an independent review committee. Clinical data cutoff date was January 31, 2020.

A total of 223 patients were randomized in the study. Of these, 97 patients had received belantamab mafodotin 2.5 mg/kg and 99 patients received belantamab mafodotin 3.4 mg/kg. The current analysis was for the belantamab mafodotin 2.5-mg/kg cohort. Of the 97 patients in the belantamab mafodotin 2.5-mg/kg cohort, the majority (75% [73 of 97]) of patients had undergone autologous stem-cell transplantation before, had received a median of 7 previous therapies; 34% had an International Staging System (ISS) stage II, and 43% had ISS stage III; and 23% had extramedullary disease at baseline. At data cutoff, patients had received a median of 3 treatment cycles, 42 patients were ongoing in the study, and 10 patients still received belantamab mafodotin 2.5 mg/kg.

At a median follow-up of 12.4 months, 31 (32%) patients achieved an overall response, and 18 responders achieved a very good partial response or better, including 7 complete responses or stringent complete responses. Median duration of response was 11.0 months, and a 50% estimated probability of maintaining a response at 12 months. The median progression-free survival was 2.8 months, with a median progression-free survival of 14 months in the very good partial response or better cohort. The median overall survival was 13.7 months; estimated 1-year overall survival rate was 58%. Subgroup analysis showed that the clinical benefit in the overall population also extended to patients with high-risk cytogenetics or renal impairment; however, outcomes were poorer in patients with extramedullary disease. In patients who had a clinical response and prolonged dose delays (>63 days, mainly because of corneal events), 88% maintained or deepened responses during their first prolonged dose delay.

Overall, there were no new safety signals during this follow-up. In the belantamab mafodotin 2.5-mg/kg cohort (N = 95), treatment-related adverse events occurred in 88% of patients and grade 3/4 treatment-related adverse events occurred in 57% of patients. Common grade 3/4 adverse events included keratopathy, thrombocytopenia, and anemia. Serious adverse events that resulted in death were reported in 3 patients, 1 of which was deemed treatment-related. Infusion-related reactions occurred in 21% of patients and were mostly grade 1/2. Keratopathy with or without best-corrected visual acuity change from baseline or symptoms occurred in 72% of patients; however, few had symptoms, and most did not experience a clinically meaningful best-corrected visual acuity decline; the majority (77%) of these events resolved with a median time to recovery of 86.5 days. The safety profile was comparable in the high-risk cytogenetics, renal impairment, and extramedullary disease subgroups.

Longer-term (13-month follow-up) data from the DREAMM-2 trial confirmed the sustained clinical activity of belantamab mafodotin in heavily pretreated patients with RRMM, with no emergence of new safety signals.

Source: Lonial S, Lee HC, Badros A, et al. Longer term outcomes with single-agent belantamab mafodotin in patients with relapsed or refractory multiple myeloma: 13-month follow-up from the pivotal DREAMM-2 study. Cancer. 2021;127:4198-4212.

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