GSK presents data from interim analysis of DREAMM-8 Phase 3 head-to-head trial

GSK announced positive results from an interim analysis of the DREAMM-8 phase III head-to-head trial evaluating belantamab mafodotin, in combination with pomalidomide plus dexamethasone, versus a standard of care, bortezomib plus PomDex, as a second line and later treatment for relapsed or refractory multiple myeloma. These late-breaking data, were presented at the 2024 American Society of Clinical Oncology Annual Meeting in Chicago, IL, were featured in the official ASCO press program and simultaneously published in the New England Journal of Medicine. On the primary endpoint of progression-free survival, a statistically significant and clinically meaningful improvement was observed with the belantamab mafodotin combination compared to the bortezomib combination. At a median follow-up of 21.8 months, the median PFS was not yet reached with the belantamab mafodotin combination compared to 12.7 months in the bortezomib combination. At the end of one year, 71% of patients in the belantamab mafodotin combination group compared to 51% in the bortezomib combination group were alive and had not progressed. A benefit for belantamab mafodotin plus PomDex was observed across all pre-specified subgroups including those with poor prognostic features, such as patients who were refractory to lenalidomide and patients with high-risk cytogenetics. A positive overall survival trend was observed but not statistically significant at the interim analysis. OS follow-up continues and further analyses are planned. At the end of one year, 83% of patients were alive in the belantamab mafodotin combination group versus 76% in the bortezomib combination group. The safety and tolerability profile of the belantamab mafodotin combination was broadly consistent with the known profile of the individual agents. Similar to the results seen in the DREAMM-7 phase III head-to-head trial, in DREAMM-8 the belantamab mafodotin combination also resulted in clinically meaningful improvements consistently across secondary efficacy endpoints, showing that the belantamab mafodotin combination resulted in deeper and more durable responses compared to the bortezomib combination. Key improvements included rate of complete response or better; minimal residual disease negativity rate; and duration of response. Grade 3 or higher non-ocular adverse events of clinical interest in the belantamab mafodotin combination versus bortezomib combination arms, respectively, included neutropenia; thrombocytopenia; and pneumonia. Eye-related side effects, a known risk of treatment with belantamab mafodotin, were generally reversible, manageable with dose modifications, and led to low treatment discontinuation rates. Grade 3 or higher ocular adverse events occurred in 43% of patients receiving the belantamab mafodotin combination. Fifty-one patients (34%) with a best corrected visual acuity of 20/25 or better in at least one eye at baseline had a worsening in both eyes to 20/50 or worse. At the time of this analysis, the first occurrence of such events had improved in 92% of these patients, and resolved in 85%, with a median time to resolution of 57 days. Global health status quality of life, as measured by the EORTC-QLQ-C30 remained stable in both treatment arms over time, suggesting that treatment did not lead to any decline in overall health related QOL.