Autologous blood stem cell transplantation for acute myeloblastic leukemiain first complete remission. Intensification therapy before transplantation does not prolong disease-free survival

Background and Objective. To compare the clinical results of two consecutiv e therapeutic protocols including autologous blood stem cell transplantatio n (ABSCT) for patients with de novo acute myeloblastic leukemia (AML) in fi rst complete remission (CR1). Design and Methods. Between November 1989 and January 1997, 50 patients wit h AML in CR1 underwent ABSCT using two consecutive protocols. In the first one (Group A, 25 patients) peripheral blood stem cells (PBSC) were collecte d after induction and consolidation chemotherapy courses, and ABSCT was per formed immediately thereafter. In the subsequent 25 patients (Group B), PBS C were collected after consolidation alone, and a further chemotherapy cour se with intermediate dose cytarabine (Ara-C 1 g/m(2)/12h x 3 days) and mito xantrone (12 mg/m(2)/d x 3 days) was administered as early intensification. The conditioning regimen consisted of busulfan (16 mg/kg) and cyclophospha mide (200 mg/kg) in every case. Results. Hematopoietic engraftment was slightly quicker in Group B, with me dian times to reach 0.5x10(9) neutrophils/L and 20x10(9) platelets/L being 13 and 12 days in Group A and 12 and 11 days in Group B, respectively. Ther e were three graft failures (8%) (2 in Group A and 1 in Group B) and three transplant-related deaths (8%) (2 in Group A and 1 in Group B). No signific ant differences were observed between the groups in terms of relapse (64% a t 4-years in Group A and 81% in Group B). Likewise, the actuarial 4-year di sease-free survival (DFS) was not significantly different between the two g roups (32% v 18%). Interpretation and Conclusions. Our study confirms that AML patients in CR1 receiving ABBOT have rapid engraftment with low mortality. However, autolo gous transplants with PBSC collected after consolidation chemotherapy were still associated with a high rate of relapse (RR). This RR was not apparent ly reduced by the administration of intermediate dose Ara-C before transpla ntation. (C)1999, Ferrata Storti Foundation.