Effect of ubenimex (Bestatin((R))) on syngeneic bone marrow transplantation in leukemic mice

We investigated the effects of ubenimex on syngeneic bone marrow transplant ation (BMT) in mice. Oral administration of ubenimex at doses of 5 or 50 mg /kg daily prolonged the survival lime of mice whose bone marrow was reconst ituted by BMT after irradiation with a lethal dose of X-rays. Based on this result, we examined the therapeutic effect of ubenimex on survival lime in C1498 leukemia-bearing mice after BMT Daily oral administration of ubenime x at 5 mg/kg prolonged the survival time of leukemia-bearing mice after tre atment with BMT: Moreover; ubenimex enhanced the cytotoxic activity of T-ly mphocytes in the leukemic cells of leukemia-bearing mice. These results sug gest that treatment with ubenimex would be a useful adjuvant therapy after BMT in patients with leukemia.