A chloroethylating nitrosourea with antineoplastic activity. Fotemustine alkylates guanine by forming chloroethyl adducts at the 6 position of guanine, resulting in N1-guanine and N3-cytosine cross linkages, inhibition of DNA synthesis, cell cycle arrest, and finally apoptosis. This agent is lipophilic and crosses the blood-brain barrier. or A substance being studied in the treatment of advanced melanoma, glioblastoma (a type of brain tumor) that has come back, and certain types of lymphoma. Fotemustine damages the cell’s DNA and may kill cancer cells. It is a type of alkylating agent and a type of nitrosourea.