CPQ and plasma cell myeloma: Melflufen is rapidly taken up by myeloma cells due to its high lipophilicity; once inside the cell, aminopeptidases cleave melflufen into melphalan and p-fluorophenylalanine; melphalan accumulates in myeloma cells and, within the nucleus, induces irreversible DNA damage and apoptosis (Figure 1) (12–14).