Myeloma Drug Pulled From Market Just Months After Approval

Just months after FDA granted accelerated approval of its myeloma drug, Oncopeptides has pulled melphalan flufenamide (melflufen, Pepaxto) from the market.

The decision followed an FDA hold on clinical trials of the drug after data from a confirmatory trial showed an increased mortality risk in patients treated with melflufen. The phase III OCEAN study compared melflufen plus dexamethasone and pomalidomide (Pomalyst) plus dexamethasone in patients with triple-refractory multiple myeloma. The trial met the primary endpoint of progression-free survival, but an analysis of overall survival (a secondary endpoint) showed melflufen on the wrong end of a hazard ratio of 1.104.

“During our dialog with FDA, it has become evident that the FDA does not consider that the phase III OCEAN study meets the criteria of a confirmatory study,” according to a statement from the company. “Oncopeptides believes that the OCEAN data are scientifically meaningful and that the findings warrant further evaluation.”

Oncopeptides will refocus R&D resources on its proprietary peptide drug conjugate platform and existing next-generation drug candidates already in the pipeline. According to the statement, Oncopeptides business units in the United States and Europe will close, and the company will become Sweden based. An application for conditional marketing of melflufen in the European Union (based on results of a phase II HORIZON trial that supported FDA accelerated approval) is still pending.

“The company now needs to refocus its resources and energy on R&D and remain true to its mission of bringing hope to patients through science,” said Oncopeptides CEO Marty J. Duvall. “We believe that this is the only viable path forward to accomplish this goal.”

The company will work with the FDA to make the melflufen available to patients currently treated with the drug.

Melflufen received accelerated approval in late February as fifth-line treatment for relapsed/refractory myeloma, including failure of three classes of myeloma drugs (immunomodulator, proteasome inhibitor, and anti-CD38 antibody). The single-arm HORIZON 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 fourth of a subgroup of 97 patients with triple-refractory disease and four prior regimens.