Allogeneic hematopoietic stem cell transplantation after rituximab-containing myeloablative preparative regimen for acute lymphoblastic leukemia

Abstract

We explored the safety and efficacy of rituximab administered in combination with the standard transplant conditioning regimen of cyclophosphamide (Cy) 120 mg/kg and total body irradiation (TBI) 12 Gy for adult patients with acute lymphoblastic leukemia (ALL). Patients were eligible if their disease expressed CD20. Rituximab was administered at 375 mg/m2 weekly for four doses beginning on day -7 of the conditioning regimen. Graft-versus-host-disease (GVHD) prophylaxis consisted of tacrolimus and methotrexate. Thirty-five patients undergoing matched sibling (n = 23) or unrelated donor (n = 12) transplantation were studied, with a median age of 30 years (range 15-55 years). At 2 years, progression-free survival, treatment-related mortality, and overall survival were 30, 24, and 47%, respectively. There was no delay in engraftment or increased incidence of infection. The cumulative incidence of grade II-IV acute GVHD was 17%, and limited and extensive chronic GVHD was 43% at 2 years. The addition of rituximab to the standard Cy/TBI transplant conditioning regimen in ALL was safe and well tolerated, and there was a suggestion of decreased incidence of acute GVHD when compared to historically reported GVHD rates for this group of patients.