The Effect of In Vivo T Cell Depletion with Alemtuzumab on Reduced-intensity Allogeneic Hematopoietic Cell Transplantation for Chronic Lymphocytic Leukemia

Reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation is increasingly considered for patients with chronic lymphocytic leukemia (CLL). To investigate the impact of in vivo T cell depletion with alemtuzumab on the incidence of graft-versus-host disease (GVHD), nonrelapse mortality (NRM), progression-free survival (PFS), and overall survival (OS), we retrospectively analyzed the outcomes of 62 consecutive CLL patients conditioned with fludarabine and melphalan at 4 institutions. For GVHD prophylaxis, 41 patients (cohort 1) received alemtuzumab and cyclosporin; and 21 patients (cohort 2) received cyclosporin plus methotrexate or mycophenolate. Donors were 50 siblings and 12 unrelated volunteers. Twenty-two (36%) patients received donor lymphocyte infusions (DLI), 20 (49%) from cohort I and 2 (10%) from cohort 2 (P = .002). Grade III-IV acute GVHD (aGVHD) was observed in 20% and 38% of patients from cohorts I and 2, respectively (P =. 14). Extensive chronic GVHD (cGVHD) was observed in 10% and 48% of patients from cohorts 1 and 2, respectively (P = .03). There was a trend toward a higher viral infection rate in cohort I compared to cohort 2 (68% versus 43%, P = .062), but the incidence of cytomegalovirus (CMV) reactivation was not significantly different. The 3-year OS, PFS, NRM, and relapse rates were 65%, 39%, 28%, and 32%, respectively, for cohort 1; and 57%, 47%, 34%, and 20%, respectively, for cohort 2 (P = .629, P = .361, P = .735, and P = 0.112, respectively). In conclusion, both methods of GVHD prophylaxis were equivalent in terms of survival. The administration of alemtuzumab led to reduced cGVHD, possibly improving quality of life.