Melphalan, also known as L-phenylalanine mustard, phenylalanine mustard, L-PAM, or L-sarcolysin, is a phenylalanine derivative of nitrogen mustard. Melphalan is a bifunctional alkylating agent which produces a number of DNA adducts with the DNA interstrand crosslink (ICL) considered to be the critical cytotoxic lesion. Melphalan is used to treat different cancers including myeloma, melanoma and ovarian cancer.

Sarcolysin is the isomeric form of melphalan with alkylating activity. Sarcolysin is a bifunctional alkylating agent. The cytotoxicity of sarcolysin appears to be related to the extent of its interstrand cross-linking with DNA, probably by binding at the N7 position of guanine. Like other bifunctional alkylating agents, it is active against both resting and rapidly dividing tumor cells. The levo-isomer - melphalan (L-sarcolysin) is approved under the brand name ALKERAN for the palliative treatment of multiple myeloma and for the palliation of non-resectable epithelial carcinoma of the ovary. In addition, the drug was approved under the trade name Evomela. Evomela is indicated for use as a high-dose conditioning treatment prior to hematopoietic progenitor (stem) cell transplantation in patients with multiple myeloma. In addition, for the palliative treatment of patients with multiple myeloma for whom oral therapy is not appropriate.

The D-isomer of melphalan, known as medphalan, is less active against certain animal tumors and the dose needed to produce effects on chromosomes is larger than that required with the L-isomer.