Bestatin treatment of myelodysplastic syndromes (MDS) and the effects of bestatin on hematopoiesis in MDS.

A high remission rate (75%) was achieved in a preliminary study using bestatin in patients with refractory anemia with excess blasts (RAEB) and RAEB in transformation (RAEB-t). One of 2 patients with RAEB-t and 3 of 6 patients with RAEB obtained complete response. Two patients with RAEB achieved good response, but one with refractory anemia failed. Clonogenic marrow cell culture studies in patients with myelodysplastic syndromes have demonstrated intrinsic hematopoietic stem cell abnormalities, in particular defective erythroid colony formation. After bestatin treatment, these abnormalities as well as hematologic findings were markedly improved. The results suggest that bestatin has an enhancing effect on burst promoting activity production of helper (CD4 positive) T lymphocytes and the effect on hematopoiesis of bestatin may be mediated by T lymphocytes.