DREAMM-7 phase III trial shows Blenrep combination nearly tripled median progression-free survival versus standard of care combination in patients with relapsed/refractory multiple myeloma- GSK

GSK plc announced results from an interim analysis of the DREAMM-7 phase III head-to-head trial evaluating Blenrep (belantamab mafodotin) combined with bortezomib plus dexamethasone (BorDex) versus daratumumab plus BorDex in second-line and later treatment of relapsed or refractory multiple myeloma. These data will be presented at the American Society of Clinical Oncology (ASCO) Plenary Series on 6 February 2024. In this trial a total of 494 participants were randomised at a 1:1 ratio to receive either belantamab mafodotin in combination with BorDex or a combination of daratumumab and BorDex. Belantamab mafodotin was scheduled to be dosed at 2.5mg/kg intravenously every three weeks. The primary endpoint is PFS as per an independent review committee. The key secondary endpoints include OS, DOR, and MRD negativity rate as assessed by next-generation sequencing.

In the primary endpoint of progression-free survival (PFS), a statistically significant and clinically meaningful improvement was observed with the belantamab mafodotin combination (n=243), showing a 59% reduction in the risk of disease progression or death (hazard ratio [HR]: 0.41 [95% confidence interval (CI): 0.31-0.53], p-value<0.00001) compared to the daratumumab combination (n=251). With a median follow-up of 28.2 months, the median PFS was 36.6 months (95% CI: 28.4-not reached [NR]) with the belantamab mafodotin combination compared to 13.4 months (11.1-17.5) in the daratumumab combination. The PFS effect was observed across all prespecified subgroups, including those who were refractory to lenalidomide and those with high-risk cytogenetics. The safety and tolerability profile of the belantamab mafodotin combination was consistent with the known profile of the individual agents.

The belantamab mafodotin combination also resulted in clinically meaningful improvements in all secondary efficacy endpoints including a doubling of complete response rate (stringent complete response plus complete response), minimal residual disease (MRD) negativity rate and median duration of response (DOR). A strong and clinically meaningful overall survival (OS) trend was observed at the interim analysis, with a 43% reduction in the risk of death (HR: 0.57 [95% CI: 0.40-0.80], p-value=0.00049), which has not yet reached the interim criteria for statistical significance of OS. OS follow-up continues and further analyses are planned.

Grade 3 or higher non-ocular adverse events of clinical interest in the belantamab mafodotin combination and daratumumab combination arms, respectively, included thrombocytopenia (55% and 35%; exposure-adjusted event rate: 40 and 29, per 100 person-years), neutropenia (12% and 6%), pneumonia (12% and 4%; exposure-adjusted event rate: 8 and 3, per 100 person-years), and anaemia (8% and 10%).

Eye-related side effects, a known risk of treatment with belantamab mafodotin, were generally reversible, manageable with dose modification, and led to low (9%) treatment discontinuations. Grade 3 or higher ocular adverse events occurred in 34% of patients receiving the belantamab mafodotin combination and primarily included blurred vision (22%), dry eye (7%), eye irritation (5%), and visual impairment (5%). Eighty-two patients (34%) with a best corrected visual acuity (BCVA) score of 20/25 or better in at least one eye at baseline had a worsening in both eyes to 20/50 or worse. Almost all these patients’ events (98%) had resolved at the time of this analysis. The median time to resolution was 22 days. Global health status quality of life (QOL) as measured by the EORTC-QLQ-C30 indicated no difference in global QOL between different treatment arms over time.

Prof. María-Victoria Mateos, Head of Myeloma and Clinical Trials Unit, Haematology Department, University of Salamanca, Spain and DREAMM-7 principal investigator, said: “These results from DREAMM-7 show how belantamab mafodotin in combination with BorDex represents a significant improvement over the daratumumab-based regimen in a second-line multiple myeloma treatment setting. Anti-BCMA therapies are helping to improve outcomes for patients with multiple myeloma, and having an off-the-shelf option, like belantamab mafodotin, that can be administered in a community oncology treatment centre where the majority of patients are treated has the potential to transform the way we treat myeloma at or after first relapse.”

Hesham Abdullah, Senior Vice President, Global Head Oncology, R&D, GSK, said: “The substantial progression-free survival benefit and strong overall survival trend compared to a daratumumab standard of care combination reinforce our belief in the potential for belantamab mafodotin used in combination to redefine the treatment of multiple myeloma at or after first relapse. We plan on sharing these results with health authorities worldwide.”