GlaxoSmithKline's (NYSE:GSK) experimental new cancer drug, belantamab mafodotin, will receive a priority review from the U.S. Food and Drug Administration. The agency's recent decision means belantamab will probably become the first of several drugs to treat multiple myeloma by hitting the same target.

Multiple myeloma is cancer formed in the plasma cells. About 30,000 adults in the U.S. are diagnosed each year with this second-most common blood cancer after non-Hodgkin lymphoma.

First on the field

Belantamab mafodotin is a protein that delivers a single-serving package of chemotherapy to cells that have beta-cell maturation antigen (BCMA) on their surface. BCMA is found almost exclusively on the surfaces of older immune cells that probably should have retired already, which makes it a popular target for drug developers trying to come up with new multiple myeloma treatments.

Scientist reading a complicated report.

Image source: Getty Images.

A priority review means Glaxo will probably receive an approval decision for belantamab mafodotin this July if not earlier. While Glaxo's BCMA-targeted drug might be the first to reach multiple myeloma patients who need a new option, a handful of competitors in late-stage development could make belantamab's commercial launch especially challenging. 

About that MVP award

In a pivotal study, 31% of advanced-stage multiple myeloma patients treated with belantamab showed a response. That's impressive, but positive outcomes seem far more likely for this patient group following treatment with JNJ-4528, a BCMA-directed therapy from Johnson & Johnson (NYSE:JNJ) or idecabtagene vicleucel (ide-cel) from partners bluebird bio (NASDAQ:BLUE) and Bristol-Myers Squibb (NYSE:BMY)

Although JNJ-4528 and ide-cel are complicated cell-based therapies, they appear far more effective than belantamab. In December, Johnson & Johnson said all 29 patients treated with JNJ-4528 responded and 20 of them achieved complete remission. Bristol-Myers and bluebird reported four out of 12 heavily pretreated multiple myeloma patients given a high dose of ide-cel achieved complete remission.