European survey of bone marrow transplantation in acute promyelocytic leukemia (M3). Working Party on Acute Leukemia of the European Cooperative Group for Bone Marrow Transplantation (EMBT).

Acute promyelocytic leukemia (M3) is a distinct subtype of AML considered to have better response to chemotherapy and a higher cure rate than other subtypes. We analyzed the outcome for 362 M3 patients transplanted in Europe from November 1979 to December 1992 and reported to the acute leukemia registry of the European Cooperative Group for Bone Marrow Transplantation (EMBT). Of these 362 patients, 187 received an autograft, 129 in first remission (CR1) and 58 in second remission (CR2), and 175 an allograft, 142 in CR1 and 33 in CR2. Patients autografted in CR1 had at 7 years a leukemia-free survival (LFS) of 48 +/- 5%, a relapse rate (RR) of 41 +/- 5% and a probability of transplant-related mortality (TRM) of 18 +/- 6%. Patients allografted in CR1 had a LFS of 42 +/- 6%, a RR of 28 +/- 5% and a TRM probability of 42 +/- 8%. For patients transplanted in CR2, the respective figures after auto and allotransplantation were: LFS: 31 +/- 7% and 22 +/- 8%, RR: 54 +/- 8% and 64 +/- 11%, TRM: 23 +/- 9% and 40 +/- 9%. These data, which do not permit comparison between autologous and allogeneic BMT, indicate that roughly 45% of M3 patients achieving CR1 may be cured by a marrow transplant. Since the recent use of transretinoic acid-containing induction regimens has increased early control for patients with AML M3, it will be important to find out how these results affect outcome following allogeneic or autologous BMT.