DREAMM-3 Trial of Belantamab Mafodotin in Multiple Myeloma Misses Primary Endpoint

The phase III DREAMM-3 trial, which compared belantamab mafodotin with pomalidomide plus low-dose dexamethasone in patients with relapsed or refractory multiple myeloma, did not meet its primary endpoint.

The primary endpoint of the open-label, randomized, head-to-head superiority trial was progression-free survival (PFS), with the PFS in DREAMM-3 demonstrating a hazard ratio of 1.03 (95% CI, 0.72-1.47), GSK plc, the manufacture of the drug, said in the announcement.

Belantamab mafodotin is an antibody-drug conjugate comprising a humanized B cell maturation antigen (BCMA) monoclonal antibody conjugated to the cytotoxic agent auristatin F by a non-cleavable linker. The U.S. Food and Drug Administration (FDA) granted the drug accelerated approval as a monotherapy for adult patients with relapsed or refractory multiple myeloma who received at least four prior therapies, including an anti-CD38 monoclonal antibody, a proteasome inhibitor, and an immunomodulatory agent.

The FDA’s accelerated approval, which was based on results from the DREAMM-2 study, was “contingent upon a confirmed clinical benefit from a randomized phase III clinical trial,” according to GSK officials.

“Data from DREAMM-3 is in the process of being shared with health authorities,” GSK plc officials said in the announcement. “Discussions with health authorities are currently ongoing.”

The median PFS was 11.2 months in patients receiving belantamab mafodotin in the DREAMM-3 trial, while it was seven months in patients who received pomalidomide plus dexamethasone. The overall response rate, one of the trial’s secondary endpoints, was 41% in patients receiving belantamab mafodotin, while it was 36% for those receiving pomalidomide plus dexamethasone. A quarter of patients receiving belantamab mafodotin had a very good partial response or better, while 8% of patients receiving pomalidomide plus dexamethasone had a very good partial response or better.

Officials said further studies of the drug will continue.

Source: GSK plc, November 2022