A comparison of Campath and Thymoglobulin as part of the conditioning before allogeneic hematopoietic stem cell transplantation

Background: In vivo T-cell depletion with anti-thymocyte globulin is a commonly used strategy for the prevention of graft-versus-host disease (GVHD) and to avoid rejection after hematopoietic stem cell transplantation (HSCT). Methods: We compared 36 patients given Campath (alemtuzumab) as part of the conditioning with a matched cohort of 72 patients receiving Thymoglobulin (TMG). Most patients had a hematologic malignancy beyond first remission. Median age was 55 (1-67). The majority of patients had an unrelated donor (70%) and 82% were given peripheral blood stem cells. Most patients received reduced-intensity conditioning. Results: Graft failure occurred in 8% of the patients in each group. No difference in time-to-engraftment of neutrophils and platelets was found. The cumulative incidence of acute GVHD of any grade was 34% and 53% (P = 0.07), and the incidence of chronic GVHD was 46% and 25% in the Campath and TMG groups, respectively. In multivariate analysis, a low antibody dose was associated with acute and chronic GVHD and Campath was correlated with chronic GVHD. No differences in transplant-related mortality (28% vs. 18%), overall survival (54% vs. 58%), and relapse-free survival (39% vs. 43%) were found between the two groups. No difference in the proportion of T and B lymphocytes during the first year after HSCT was found. Conclusions: TMG and Campath as part of the conditioning result in similar outcome. Campath was associated with less acute but more chronic GVHD.