Patients with advanced multiple myeloma have a new treatment option with the FDA’s approval of a GlaxoSmithKline drug that targets B-cell maturation antigen, a protein found on the surface of cancerous plasma cells.
The agency OK’d the London-based pharma giant’s cancer drug, belantamab mafodotin (Blenrep), based on the results of a study in which patients with the blood cancer received the drug intravenously every three weeks until their disease progressed or the side effects became too much to handle.
Patients that received the GSK (NYSE: [[ticker:GSK]]) drug in the trial, dubbed DREAMM-2, had previously undergone a median of seven prior lines of treatment. The FDA OK’d belantamab mafodotin for patients who have received at least four prior treatments, including an antibody drug targeting the protein CD38, a proteasome inhibitor, and an immunomodulator.
More than 32,000 people in the US are estimated to be diagnosed this year with multiple myeloma, the second most common blood cancer in the US, and nearly 13,000 people are predicted to die from the disease, according to the American Cancer Society.
The GSK study, in patients with forms of the disease that had not or were no longer responding to other treatments, tested two doses. Of the 97 patients who received the lower dose, which is what the agency approved, the overall response rate—those who saw the extent of cancer in their body reduced by at least a predetermined amount or disappear entirely—was 31 percent. For 73 percent of those patients, the response lasted six months or more.
However, patients also experienced serious side effects, primarily impacting their eyes. The most common side effects that patients experienced were changes in the outermost layer of the cornea, a decrease in their ability to see small details, nausea, blurred vision, fever, infusion-related reactions, and fatigue. Those risks prompted an FDA advisory committee to meet and review the belantamab mafodotin application; in June, the committee unanimously recommended approval. The agency isn’t bound by such recommendations, but typically follows them.
A warning on the drug’s label directs prescribers to conduct regular eye exams to monitor the severity of any ocular changes. And with approval of the drug came a requirement for “risk evaluation and mitigation strategies” (REMS), plans to communicate the risks associated with the drug to physicians and patients alike.
GSK is not the only company targeting B-cell maturation antigen (BCMA). Bristol Myers Squibb (NYSE: [[ticker:BMY]]) and Bluebird Bio (NASDAQ: [[ticker:BLUE]]) are advancing an experimental CAR-T therapy for multiple myeloma. But the FDA returned their submission for the investigational drug, idecabtagene vicleucel (ide-cel), in May with a request for more information about how the product is made. The companies last week resubmitted their application.
San Diego biotech Poseida Therapeutics (NASDAQ: [[ticker:PSTX]]), with backing from Novartis (NYSE: [[ticker:NVS]]) among other investors, is in Phase 2 testing with a CAR-T therapy for multiple myeloma that targets BCMA. Data on another anti-BCMA CAR-T therapy in Phase 2 testing for the disease, a drug being developed by Legend Biotech (NASDAQ: [[ticker:LEGN]]) in partnership with Janssen Biotech, a Johnson & Johnson (NYSE: [[ticker:JNJ]]) subsidiary, contributed to the company’s upsized June IPO. The company, in what was then then the year’s largest biotech offering, raked in about $424 million. The company has said that it may submit an application for the experimental drug to the FDA this year.
GSK, using technology licensed from Seattle Genetics (NASDAQ: [[ticker:SGEN]]) and BioWa, took a different approach. Belantamab mafodotin is an antibody-drug conjugate, a type of drug that leverages both the ability of an antibody to home in on a target plus the cancer-killing properties of toxic agents. To maintain the drug’s approval the company will need to conduct additional clinical tests because it was OK’d under an accelerated pathway, under which regulators consider drug applications on a thinner body of evidence than is standard in order to make a new treatment available to patients more quickly.
The Wednesday approval was GSK’s first for a novel oncology drug since 2015, when it sold its targeted cancer drugs to Novartis for $16 billion, and its second oncology nod this year. In April the FDA OK’d (niraparib) Zejula as a first-line maintenance treatment—a type of therapy intended to stave off cancer’s return following a positive response to chemotherapy—for women with advanced ovarian cancer.
