- GlaxoSmithKline aims to be the first drugmaker to win U.S. approval for a new type of multiple myeloma therapy, confirming Monday the submission of an application to the Food and Drug Administration for a drug known as belantamab mafodotin.
- The pharma's bid for approval is supported by data from an open-label Phase 2 trial that tested GSK's therapy in very sick patients with the blood cancer, which emerges from the bone marrow. Yet the detailed results shared by GSK raise serious doubts of how competitive belantamab mafodotin will be in a fast-moving field.
- Earlier this month, the American Society of Hematology's annual meeting featured updates from a number of rival drugmakers on competing drugs that target the same B cell protein as GSK's. Bristol-Myers Squibb, for example, plans to soon submit its CAR-T cell therapy ide-cel.
Cancer is one of the most crowded areas of drug development. And within it, clinical testing of multiple myeloma therapies aimed at a protein called B-cell maturation antigen, or BCMA, has become intensely competitive.
A tally by the investment bank Bernstein found 35 anti-BCMA drug programs were presented at ASH, many of which were part of a new class of drugs called CAR-T cell therapies.
GSK is taking a different approach with belantamab mafodotin, which is an antibody-drug conjugate. Such treatments combine a cancer-seeking antibody with a toxic compound that's designed to destroy malignant cells.
Belantamab mafodotin is particularly crucial for GSK, which, under R&D chief Hal Barron, is seeking to reestablish itself in oncology. The pharma has prioritized development of the drug, with three studies testing the medicine recruiting patients and another five planned to start over the next several years.
In DREAMM-2, the study on which GSK is making its case to regulators, treatment with belantamab mafodotin led to responses in 30 of 97 patients given a 2.5 mg/kg dose. Three achieved a complete response.
That 31% response rate, while notable in a group of patients that had received a median of seven prior drugs, is lower than what GSK reported in an earlier study. And it's significantly below what was recently disclosed at ASH for programs from Bristol-Myers Squibb and Johnson & Johnson.
Bristol-Myers Squibb and Bluebird bio's ide-cel, for example, posted a 73% response rate in patients who were triple refractory to drugs from each of the three main classes of multiple myeloma therapies. Thirty-one percent experienced complete responses.
And early data from J&J's anti-BCMA CAR-T impressed with a 100% response rate in 29 patients, 25 of whom were triple refractory.
CAR-Ts are complex treatments and come with the risk of serious side effects. Using an antibody-drug conjugate, like GSK's is doing, could offer benefits in convenience and ease-of-administration.
But GSK's belantamab mafodotin comes with notable safety risks too. Forty percent of patients on the 2.5 mg/kg dose experienced a serious adverse event, including a type of eye condition called keratopathy in 26 of 95 patients.
An application to the FDA, if accepted on time, sets up a decision on approval sometime in the latter half of next year. By then, though, GSK may be joined on the market by Bristol-Myers Squibb, and a field of competitors one step closer to threatening what's forecast to be the pharma's top cancer drug.