The first-in-class drug belantamab mafodotin (Blenrep, GlaxoSmithKline) has been recommended for conditional marketing approval in the European Union (EU) for use in the treatment of relapsed and refractory multiple myeloma in patients who have already tried other therapies.
The product was accepted into the European Medicines Agency (EMA) PRIME program for medicines that have potential to address unmet medical needs, the agency noted.
Belantamab mafodotin was also recently recommended for US approval when a Food and Drug Administration (FDA) advisory committee voted 12-0 in favor of the drug’s benefits outweighing risks in this patient population.
Specifically, these patients with refractory or relapsed multiple myeloma should have already tried treatment with one of the three major classes of drugs, namely an immunomodulatory agent, a proteasome inhibitor, and a CD-38 monoclonal antibody.
For patients who no longer respond to these drugs, the outlook is bleak, the EMA said. There is an unmet medical need for new treatments that improve survival of these patients beyond the currently observed 3 months or less.
Belantamab mafodotin has a novel mechanism of action: it targets B-cell maturation antigen (BCMA), a protein present on the surface of virtually all multiple myeloma cells, but is absent from normal B-cells, thus “making it an ideal drug target,” the agency remarked.
The product is an antibody–drug conjugate that combines a monoclonal antibody that targets BCMA with the cytotoxic agent maleimidocaproyl monomethylauristatin F (mcMMAF). It homes in on BCMA on myeloma cell surfaces, and once inside the myeloma cell, the cytotoxic agent is released leading to apoptosis, the “programmed” death of the cancerous plasma cells, the agency explained.
Results From Open-Label Study
The recommendation for conditional marketing authorization comes from the EMA Committee for Medicinal Products for Human Use (CHMP) and was based on a phase 2, open-label, randomized, two-arm study, DREAMM-2.
The study investigated the efficacy and safety of two doses of belantamab mafodotin in patients with multiple myeloma who still had active disease after three or more lines of therapy and who no longer responded to treatment with immunomodulatory drugs, proteasome inhibitors, and an anti-CD38 monoclonal antibody.
Six-month results were published in December in The Lancet Oncology. The overall response rate was 31% in the cohort given a 2.5-mg/kg dose of the drug; 30 of 97 patients had outcomes that met the study’s positive threshold.
Another 99 patients in DREAMM-2 received a dose of 3.4 mg/kg, which was judged to have a less favorable safety profile.
The EMA has requested further clinical data, including final results from the phase 2 study, as well as results from a confirmatory phase 3 trial comparing belantamab mafodotin with pomalidomide plus low-dose dexamethasone (a standard treatment option for relapsed and refractory multiple myeloma).
One of the most common side effects of the new drug experience by participants in clinical trials was keratopathy, which affects the cornea. This ocular toxicity was seen at both drug doses.
The EMA noted that patients taking the drug would need to undergo specific ophthalmic examinations so that any findings can be promptly and adequately managed. As for all medicines, a risk management plan (RMP) will ensure rigorous safety monitoring of the medicine once authorized across the EU, it added.
At the FDA advisory committee meeting, it was noted that 44% of patients in the group that received the 2.5-mg/kg dose experienced at least one episode of severe keratopathy. In some patients, the ocular side effects caused severe vision loss that interfered with patients’ activities of daily living, such as driving and reading, FDA staff said.
For the United States, the manufacturer proposed a risk evaluation and mitigation strategy (REMS) for the detection and treatment of potential complications of belantamab. This includes recommendations for ophthalmic examinations, including assessment of best corrected visual acuity prior to each treatment cycle and promptly for patients with worsening symptoms.
One of the FDA advisory committee panelists, Gita Thanarajasingam, MD, assistant professor of medicine at the Mayo Clinic, in Rochester, Minnesota, said belantamab appeared to be well tolerated with the exception of ocular toxicity. Physicians need to acknowledge how severe this risk may be for patients while keeping in mind that belantamab still may be more tolerable for some than current treatments, she said.
“It’s reasonable to leave open the option for decision-making. Patients can express their values and preferences,” Thanarajasingam said. “There’s adequate, albeit not complete, information to guide this risk–benefit discussion in a REMS program.”
Heidi D. Klepin, MD, a professor at Wake Forest University Health Sciences, Winston Salem, North Carolina, agreed that the informed consent process should allow patients “to choose whether the trade-off is worth it” with belantamab.