The approval and withdrawal of melphalan flufenamide (melflufen): Implications for the state of the FDA.

In October 2021, melphalan flufenamide (melflufen) was withdrawn from the US market for the treatment of multiple myeloma. The decision occurred based on results from a phase 3 randomized controlled trial (RCT) which showed numerically inferior overall survival, which previously led the FDA to halt all trials involving this drug. We highlight four issues raised by the approval fate of melflufen. First, the OCEAN trial was designed with a substandard control arm: negative results occurred despite this bias theoretically favoring the experimental arm. Second, a new compound, derived from a well-known drug, is not well fitting the accelerated pathway principles, unless being robustly tested against its parent drug. Third and four, allowing a new compound on the market, while there are known alternatives, and imminent confirmatory data, has the potential to harm patients while bringing earlier market share and profit to the company. While the FDA and the company should be commended for pushing a potentially dangerous product off the US market despite recent approval, yet a re-evaluation of regulatory processes is needed to ensure that cancer patients have timely access to effective medications while being protected against potentially detrimental ones.