Ritrosulfan (also known as R-74 and Lycurim) is a sulfonate-based alkylation agent that might exert antineoplastic activity, acting to stop the development of a tumor. By alkylating DNA and producing crosslinks, ritrosulfan is thought to cause tumor cell cycle arrest. However, no alkylating activity could be demonstrated in the plasma of cancer patients, using intracavitary application of ritrosulfan. Other studies in the 1980’s have confirmed some immunodepressive properties of ritrosulfan in cancer patients, but no information is available on current development of ritrosulfan.