Allogeneic stem cell transplantation of adult chronic myelomonocytic leukaemia. A report on behalf of the Chronic Leukaemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

Abstract

We report the results of 50 allogeneic transplantations from related (n = 43) or unrelated (n = 7) donors, performed for chronic myelomonocytic leukaemia (CMML) in 43 European centres. The median age at transplant was 44 years (range 19-61). Eighteen patients had excess blasts ranging from 5% to 30% at the time of transplantation. Two graft failures were observed (4%). Neutrophil (> 0.5 x 109/l) and platelet engraftment (> 50 x 109/l) was reached after a median of 17 d (range 11-38) and 27 d (range 11-48) respectively. Acute graft-versus-host disease (GvHD grade II-IV was seen in 35% of patients, while 20% developed severe-acute GvHD grade III/IV. Twenty-six patients (52%) died of treatment-related causes. After a median follow-up of 40 months (range 11-110), the 5-year-estimated overall survival was 21% (95% CI: 15-27%) and the 5-year-estimated disease-free survival (DFS) was 18% (95% CI: 13-23%). Earlier transplantation in the course of disease, male donor, use of unmanipulated grafts, allogeneic transplantation and occurrence of acute GvHD favoured better DFS, but did not reach statistical significance. The 5-year estimated probability of relapse was 49%. The data showed a trend for a lower relapse probability of acute GvHD grade II-IV (24% vs 54%; P = 0.07), and for a higher relapse rate in patients with T cell-depleted grafts (62% vs 45%), suggesting a 'graft-versus-CMML effect'.