FDA experts okay GSK's multiple myeloma drug despite safety worries

GlaxoSmithKline’s potential first-in-class multiple myeloma drug belantamab mafodotin has taken a step closer to US approval after unanimous backing from a panel of expert advisers convened by the FDA.

The Oncology Drugs Advisory Committee’s (ODAC) 12-0 vote in favour of approval is not binding, but the FDA usually follows the advice of its advisers. 

There had been doubts about whether the ODAC would back the drug after FDA reviewers raised concerns about ocular safety in a briefing document posted online ahead of yesterday’s meeting. 

But the ODAC’s vote clears the way for a potential approval in the coming weeks, when the regulator is legally expected to conclude its fast six-month review and reach a decision. 

If approved belantamab mafodotin, which includes linker technology that GSK licensed from Seattle Genetics, will be the first in a new class of drugs that work against a target known as B-cell maturation antigen (BCMA). 

BCMA is highly expressed in multiple myeloma and belantamab mafodotin, an antibody-drug conjugate, and works by binding to the receptor and delivering a toxic payload to cancer cells while leaving healthy tissue alone. 

GSK is seeking approval in patients with relapsed or refractory multiple myeloma who have received at least four prior therapies, including an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 antibody such as Johnson & Johnson’s Darzalex. 

There are several other drugs in development targeting BCMA – Bristol-Myers Squibb’s CAR-T bb2121, Amgen’s bispecific antibody AMG 420, and another CAR-T being developed by Johnson & Johnson’s Janssen unit and China’s Legend Biotech. 

A GSK spokesperson said in a statement: “We believe that belantamab mafodotin has significant potential for patients with relapsed or refractory multiple myeloma whose disease continues to progress despite current standard of care treatment options.  

“We are committed to working closely with the FDA to complete the review of belantamab mafodotin for these patients who have limited treatment options.”