Effective treatment of adult T cell leukemia/lymphoma with a novel oral antitumor agent, MST-16.

Adult T cell leukemia/lymphoma (ATLL) induced by human T cell leukemia virus I is resistant to conventional therapy. Six patients with ATLL were treated with a new antitumor agent, MST-16, which is a derivative of bis(2,6-dioxopiperazine). Two patients achieved complete remission, lasting 12 months and more than 8 months, and 2 others partial remission, lasting 2 months and 6 weeks, respectively. The major toxicity was myelosuppression. Other toxicities were not severe and were well tolerable. Orally administered MST-16 is a promising agent for the treatment of ATLL.