The drug was granted an accelerated approval by the FDA in February 2021, for use in combination with dexamethasone in adults with relapsed or refractory multiple myeloma who have received at least four prior lines of therapy.
However, the phase 3 OCEAN study raised concerns about safety, as it showed a higher mortality associated with melphalan flufenamide in the experimental arm, compared with pomalidomide (Pomalyst).
The FDA already flagged this issue in July 2021, issuing a safety alert flagging the increased risk for death observed in the OCEAN trial among patients receiving melphalan flufenamide versus pomalidomide (47.6% vs. 43.4%) and a 5.3-month shorter overall survival.
The issue was also discussed in September 2022 by FDA’s Oncologic Drugs Advisory Committee, which voted 14-to-2 against maintaining the accelerated approval, citing an unfavorable risk/benefit profile.
The company stopped marketing the drug in the United States in October 2021 at the FDA’s request but continued to make it available for patients already undergoing treatment.
However, in March 2022, Oncopeptides rescinded the letter that voluntarily withdrew the agent from market, after further review of overall survival data from the OCEAN trial led the company to reconsider its decision. Notably, marketing efforts were still discontinued while the company worked with the FDA to interpret the data, it stated in the press release.
That review of the data showed that progression-free survival was 42% higher with melphalan flufenamide versus pomalidomide and overall response rates were 32.1% versus 26.5%, respectively.
Now, the FDA has requested that the company withdraw its U.S. marketing authorization.
“We respect FDA’s accelerated approval regulations,” Jakob Lindberg, CEO of Oncopeptides commented in the press release.
However, he also added, “multiple myeloma remains an incurable disease, and the treatment options for patients with triple-class refractory disease will ultimately become exhausted. The OCEAN study demonstrated clinical benefit for multiple myeloma patients, in particular for nontransplanted elderly patients where the unmet medical need remains very high.”
Commercialization of the drug in Europe, under the brand name Pepaxti, is ongoing.
“Pepaxti has a full approval from the European Medicines Agency, EMA, since Aug. 18, 2022, and was approved by the Medicines and Healthcare Products Regulatory Agency, MHRA, in the U.K. on Nov 11, 2022,” the company noted.
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