TREOSULFAN-BASED CONDITIONING REGIMEN PRIOR TO ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN ADULT PATIENTS WITH HEMATOLOGICAL MALIGNANCIES IS NON TOXIC, BUT NOT MYELOABLATIVE

For many decades the main myeloablative conditioning regimen prior to allogeneic hematopoietic stem cell transplant (allo-HCT) consists of busulfan (16 mg/kg) and cyclophosphamide (120 mg/kg). The rate of transplanted-related mortality as a result of toxicity is still high. However alternative regimens are now available. These regimens allow to reduce toxicity and to get favorable outcomes. Aware of the serious toxic complications when using high doses of busulfan initiated the search for alternative programs. We studied conditioning regimen of the therapy with treosulfan 36 g/m(2) + cyclophosphamide 120 mg/m(2) as myeloablative,but low toxic for allo-HCT in 18 patients with hematological malignancies from the high-risk group (allo-HCT has been performed not in first remission, patients with unfavorable cytogenetic abnormalities). The median of the age was 27 years (from 19 to 40 years). During the early posttransplant period no severe toxic complications were registered in the study group. Not bad results were got during 2 years after allo-HCT. The overall survival rate in the group of patients with acute myeloid leukemia accounted for 77.8% and in the group of patients with acute lymphoblastic leukemia -66.7%. On the day +30 full donor chimerism was detected only in 12 patients (66%). However on day +90 in 8 cases (44.4%) the graft rejection was recorded.