Risk factors for outcomes after unrelated cord blood transplantation for adults with acute lymphoblastic leukemia: a report on behalf of Eurocord and the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

We performed a retrospective analysis on 421 adult patients who underwent unrelated cord blood transplantation (UCBT) for ALL. Median age was 32 years; 46% were in first CR (CR1), 32% in CR2 and 22% had advanced disease. Double UCBT was performed in 173 patients (41%). Myeloablative conditioning (MAC) was given to 314 patients (75%). Cumulative incidence (CI) of 60-day neutrophil recovery was 78%. CI of acute and chronic GVHD was 33 and 26%, respectively. Non-relapse mortality (NRM) at 2 years was 42%. Age >= 35 years (P < 0.0001), advanced disease at UCBT (P < 0.0001) and use of MAC (P < 0.0001) were associated with increased NRM. Relapse incidence (RI) at 2 years was 28%; use of reduced intensity conditioning (RIC) (P = 0.0002) was associated with increased RI. Two-year leukemia-free survival (LFS) was 39% for patients in CR1, 31% for CR2 and 8% for advanced disease. In multivariate analysis, factors associated with decreased LFS rate were: age >= 35 years (P = 0.034), use of MAC (P = 0.032) and advanced disease (P < 0.0001). These results show that UCBT is a valuable option to treat high-risk adult ALL when in remission. Strategies to decrease toxicity and relapse are needed to improve final outcomes.