In February 2021, the FDA approved Pepaxto (melphalan flufenamide; from Oncopeptides AB), for the treatment (in combination with dexamethasone) of adults with relapsed or refractory multiple myeloma who had received 4 or more lines of therapy and whose disease has not responded to 3 types of drugs, including a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 monoclonal antibody. Pepaxto is the first peptide–drug conjugate approved for multiple myeloma.
“Research has shown melphalan flufenamide to be a novel and innovative therapeutic option, which is active in refractory disease and has manageable toxicity, with the convenience of being administered by infusion once a month,” said Paul G. Richardson, MD, Director of Clinical Research at the Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute. “Based on our findings, melphalan flufenamide is an important addition to the treatment armamentarium, with the potential to meaningfully improve outcomes in an area of important unmet medical need.”
This approval was based on results for 97 patients with relapsed or refractory multiple myeloma who previously received 4 or more therapies. The patients received intravenous Pepaxto on day 1 and oral dexamethasone on days 1, 8, 15, and 22 of every 28-day cycle, until disease progression or until unacceptable side effects.
The overall response rate was 23.7% and the average duration of response was 4.2 months.
The most common side effects with melphalan flufenamide were fatigue, nausea, diarrhea, fever, and respiratory tract infection.