Just months after the FDA granted fast-track approval for its myeloma drug, Oncopeptides withdrew melphalan flufenamide (melflufen, Pepaxto) from the market.
The move follows an FDA suspension of the drug’s clinical trials after data from a confirmatory trial showed an increased risk of mortality in patients treated with melflufen. The phase III OCEAN study compared melflufen plus dexamethasone and pomalidomide (Pomalyst) plus dexamethasone in patients with refractory triple myeloma. The trial met the primary endpoint of progression-free survival, but an analysis of overall survival (a secondary endpoint) showed melflufen to be on the wrong side of a risk ratio of 1.104.
“During our dialogue with the FDA, it became clear that the FDA does not consider the Phase III OCEAN study to meet the criteria for a confirmatory study,” according to a statement from the company. “Oncopeptides believes the data from OCEAN is scientifically significant and the results warrant further evaluation.”
Oncopeptides will refocus its R&D resources on its proprietary peptide and drug conjugate platform and on new generation drug candidates already in development. According to the statement, Oncopeptides’ business units in the United States and Europe will close and the company will become based in Sweden. A conditional marketing application for melflufen in the European Union (based on the results of a HORIZON phase II trial that supported fast-track FDA approval) is still pending.
“The company must now refocus its resources and energy on R&D and stay true to its mission of bringing hope to patients through science,” said Marty J. Duvall, CEO of Oncopeptides. “We believe this is the only viable path to achieve this goal.”
The company will work with the FDA to make melflufen available to patients currently being treated with the drug.
Melflufen received accelerated approval in late February as a fifth-line treatment for relapsed / refractory myeloma, including the failure of three classes of myeloma drugs (immunomodulator, proteasome inhibitor, and anti-CD38 antibody). The HORIZON single-arm trial involved 157 patients with relapsed / refractory disease who received melflufen until disease progression or unacceptable toxicity. The therapy produced objective responses in about a quarter of a subset of 97 patients with triple refractory disease and four prior regimens.