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# CDER Defends Pepaxto Withdrawal Proposal
- URL: https://www.fdaweb.com/cder-defends-pepaxto-withdrawal-proposal/
- Published: 2023-09-12T12:00:00.000Z
- Updated: 2026-09-14T18:55:43.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5155305

In its response to an Oncopeptides AB written [appeal](https://www.fdaweb.com/oncopeptides-appealing-drug-withdrawal-request/) challenging CDER’s proposal to withdraw Pepaxto (melphalan flufenamide) from the market, CDER says the required study to confirm the drug’s accelerated approval did not meet the prespecified primary endpoint. “The sponsor’s assertion that the primary endpoint demonstrated statistically significant improvement is based on a post-hoc analysis and using censoring rules with which the division disagreed prior to the conduct of the primary analysis,” the [response](https://downloads.regulations.gov/FDA-2023-N-3167-0011/attachment%5F1.pdf?ref=fdaweb.com) says.

“In sum,” it says, “CDER has carefully evaluated the data and science underlying melphalan flufenamide’s results, including the results of OP-103 and the sponsor’s analyses and arguments, and concluded that, for two independent reasons, the statutory standard for withdrawal is met — the confirmatory trial failed to verify clinical benefit, and the drug is no longer shown to be safe and effective under its approved conditions of use. The significant safety risks and overall survival results, together with data failing to demonstrate benefit, decidedly show that the benefit/risk profile of melphalan flufenamide is unfavorable…. FDA should withdraw approval. To do otherwise could place patients at greater risk for harm.”

Pepaxto was given accelerated approval on 2/26/2021 to be used in combination with dexamethasone to treat adults with relapsed or refractory multiple myeloma who have received at least four prior lines of therapy and whose disease is refractory to at least one proteasome inhibitor, one immunomodulatory drug, and one CD38-directed monoclonal antibody.