Tri(1-aziridinyl)phosphine sulfide is useful for the treatment of cancers, especially cancers resistant to chemotherapy. Antineoplastic. Thio-TEPA (N,N?N?-triethylenethiophosphoramide) is used as a cancer chemotherapeutic, alkylating agent. It is used to treat various kinds of cancer such as breast, ovarian and bladder cancer. It is also used as conditioning treatment prior to hematopoietic progenitor cell transplantation (HPCT)