Wikipedia
Atrimustine ( INN) (former developmental code name KM-2210), also known as bestrabucil or busramustine, is a nitrogen mustard alkylating antineoplastic drug that was under development in Japan by Kureha Chemicals (now Kureha Corporation) for the treatment of breast cancer and non-Hodgkin's lymphoma as well as the prevention of graft-versus-host disease in bone marrow transplant recipients.1 It is the benzoate of a conjugate of estradiol and chlorambucil, which results in targeted/site-directed DNA alkylating activity toward estrogen receptor-positive tissues such as breast and bone. It reached preregistration for the treatment of cancer but was ultimately discontinued.2 Estrogenic side effects of the drug in clinical trials included vaginal bleeding and gynecomastia.3