Favorable outcomes with alemtuzumab-conditioned unrelated donor stem cell transplantation in adults with high-risk Philadelphia chromosome-negative acute lymphoblastic leukemia in first complete remission

Background Approximately 40% of adults with Philadelphia chromosome-negative acute lymphoblastic leukemia achieve long-term survival following unrelated donor hematopoietic stem cell transplantation in first complete remission but severe graft-versus-host disease remains a problem affecting survival. Although T-cell depletion abrogates graft-versus-host disease, the impact on disease-free survival in acute lymphoblastic leukemia is not known Design and Methods We analyzed the outcome of 48 adults (median age 26 years) with high-risk, Philadelphia, chromosome-negative acute lymphoblastic leukemia undergoing T-cell depleted unrelated donor-hematopoietic stem cell transplantation (67% 10 of 10 loci matched) in first complete remission reported to the British Society of Blood and Marrow Transplantation 3 Registry from 1990 to 2005. Results T-cell depletion was carried out by in vivo alemtuzumab administration Additional, ex vivo T-cell depletion was performed in 21% of patients. Overall Survival, disease-free survival and non-relapse mortality rates at 5 years were 61% (95% CI 46-75); 59% (95% CI 45-74) and 13%, (95% CI 3-25), respectively The incidences of grades II-TV and III-TV acute graft-versus-host disease were 27% (95% CI 16-44) and 10% (95% CI 4-25), respectively The actuarial estimate of extensive chronic graft-versus-host disease at 5 years was 22% (95% CI 13-38). High-risk cytogenetics at diagnosis was associated with a lower 5-year overall survival (47% (95% CI 27-71) vs 68% (95% CI 44-84), p=0.045). Conclusions T-cell depleted hematopoietic stem cell transplantation from unrelated donors can result in good overall survival and low non-relapse mortality for adults with high-risk acute lymphoblastic leukemia in first complete remission and merits prospective evaluation