GlaxoSmithKline's belantamab mafodotin leads to 31% overall response rate in multiple myeloma study

GlaxoSmithKline announced Tuesday full results from the DREAMM-2 study, with data showing that a lower dose of belantamab mafodotin was associated with an overall response rate (ORR) of 31% in patients with relapsed or refractory multiple myeloma. The company reported in August that the pivotal trial met its primary objective, with the anti-BCMA agent, also known as GSK2857916, demonstrating a clinically meaningful ORR.

The drugmaker also confirmed on Tuesday the submission of a filing to the FDA seeking approval of the lower dose of belantamab mafodotin for the treatment of patients with relapsed or refractory multiple myeloma whose prior therapy included an immunomodulatory agent, a proteasome inhibitor and an anti-CD38 antibody. Hal Barron, president of R&D, remarked "data from the DREAMM-2 study show that, if approved, belantamab mafodotin could offer an important new treatment option for these patients."

The trial included 196 patients with relapsed multiple myeloma, who were refractory to an immunomodulatory drug, a proteasome inhibitor, and to treatment with an anti-CD38 antibody, and investigated two doses of belantamab mafodotin given every three weeks. GlaxoSmithKline noted that of the 97 patients who responded to treatment with the lower dose of belantamab mafodotin, 18 subjects achieved a very good partial response or better, including three people with stringent complete or complete responses. The drugmaker added that overall survival in patients achieving a response was not reached in the six month follow-up period. Meanwhile, the ORR in patients given the higher dose of belantamab mafodotin was 34%.

Results from the study, which were also published in The Lancet Oncology, showed that the three most commonly reported Grade 3 or 4 adverse events in the lower-dose arm were keratopathy at 27%, thrombocytopenia at 20% and anaemia at 20%. In addition, Grade 3 or 4 adverse events in patients given the higher dose of belantamab mafodotin were 21% for keratopathy, 33% for thrombocytopenia and 40% for anaemia. Meanwhile, two deaths were potentially treatment related, with one case of sepsis in the lower-dose group and one case of haemophagocytic lymphohistiocytosis in the higher-dose arm.

GlaxoSmithKline is also evaluating belantamab mafodotin as third-line monotherapy in relapsed or refractory multiple myeloma and in combination with other treatments in the first- and second-line setting as part of the broader DREAMM clinical development programme. The drug comprises a humanised anti- BCMA monoclonal antibody conjugated to the cytotoxic agent auristatin F via non-cleavable linker. The drug linker technology is licensed from Seattle Genetics, while the monoclonal antibody is produced using POTELLIGENT Technology licensed from BioWa.

Earlier this month, Johnson & Johnson reported data at the American Society of Hematology (ASH) annual meeting showing that the addition of Darzalex (daratumumab) to Amgen's Kyprolis (carfilzomib) and dexamethasone significantly improved progression-free survival in patients with relapsed or refractory multiple myeloma, resulting in a 37% reduction in the risk of progression or death. Results also demonstrated that Darzalex was associated with an ORR of 84%, with a complete response rate of 29%.

Axel Hoos, head of oncology R&D at GlaxoSmithKline, said the response rate for belantamab mafodotin should go up with every earlier cycle of treatment. "We are pretty confident that we can actually achieve the same (response rates) if not more and eventually even beat Darzalex in some settings," he remarked.

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