FDA approves Oncopeptides' PEPAXTO ( melphalan flufenamide) for patients with relapsed or refractory multiple myeloma STOCKHOLM, Feb. 26, 2021 /PRNewswire/ -- Oncopeptides AB (publ) (Nasdaq Stockholm: ONCO ), a global biotech company focused on the development of therapies for difficult-to-treat hematological diseases, today announced that the U.S. Food and Drug Administration, FDA, has approved PEPAXTO (melphalan flufenamide, also known as melflufen), in combination with dexamethasone, for the treatment of adult patients 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 agent, and one CD38-directed monoclonal antibody.