A Study of Melphalan Flufenamide (Melflufen) Plus Dexamethasone in Patients With Relapsed or Refractory Multiple Myeloma

Melphalan flufenamide (melflufen) is a peptide-drug conjugate that rapidly delivers an alkylating payload into tumor cells. Peptidases are expressed in several cancers, including solid tumors and hematologic malignancies. Melphalan flufenamide is rapidly taken up by myeloma cells due to its high lipophilicity. Once inside the myeloma cell, the activity of melphalan flufenamide is determined by its immediate cleavage by peptidases into hydrophilic alkylator payloads that are entrapped. Melphalan flufenamide is 50-fold more potent than melphalan in myeloma cells in vitro due to increased intracellular alkylator concentration. It rapidly induces irreversible DNA damage leading to apoptosis of myeloma cells. Melphalan flufenamide displays cytotoxic activity against myeloma cell lines resistant to other treatments, including alkylators, in vitro. Melphalan flufenamide also has demonstrated inhibition of angiogenesis and DNA damage with a lack of functional DNA repair in preclinical studies.