Petreatment with Rituximab Reduces the Incidence of Chronic Graft-Versus-Host Disease after Allogeneic Stem Cell Transplantation in Patients with B Cell Lymphoma.

The use of anti-B cell antibodies before allogeneic hematopoietic stem cell transplantation (HSCT) induces a depletion of recipient B cells. This leads to a reduction of the number of potential antigen presenting cells and thereby might hamper the induction phase of graft-versus-host disease (GvHD). The humanized anti-CD20 antibody Rituximab has been used with increasing frequency to treat patients with B cell Non-Hodgkin’s Lymphoma. Only recently, several investigators have reported on the efficacy of Rituximab for the treatment of chronic GvHD. We therefore hypothesized, that patients who received Rituximab before being scheduled for allogeneic HSCT may have a decreased risk of GvHD.

A retrospective analysis in 72 patients after allogeneic hematopoietic stem cell transplantation for indolent (n=18), aggressive (n=45) B cell lymphoma or mantle cell lymphoma (n=9) was performed at two centres. Whereas 28 patients had received chemotherapy only before allogeneic HSCT, 44 patients had received 4–8 (median 6) cycles of 375 mg/m² Rituximab before the start of conditioning therapy. Patient characteristics’ were comparable except for a higher proportion of unrelated donors (73% vs. 54%) and a higher median age (48 vs. 42 years) in the cohort with Rituximab pre-treatment. In addition the proportion of patients having received a previous autologous transplantation was higher (63% vs. 46%) and therefore more recipients received dose reduced conditioning before allogeneic tranplantation (70% vs. 50%) in the Rituximab group.

With a median follow-up of 24 months for all patients, no significant differences in overall survival, progression-free survival and treatment-related mortality could be detected between both groups. Although the proportion of transplants from unrelated donors was lower in the No-Rituximab group, the rate of acute GvHD grade I–IV was higher (88% vs. 63%, p=0.03). The incidence of grade II–IV and grade III–IV GvHD was not significantly different between both cohorts. Chronic GvHD occurred more often in patients who had not received Rituximab before allogeneic transplantation (52% vs. 23%, p=0.02).

Although the retrospective nature of our study does not allow to draw definitive conclusions, the rate of chronic GvHD seems to be lower when anti-CD20 treatment is performed before allogeneic HSCT. Prospective studies incorporating Rituximab for the prophylaxis and therapy of GvHD are warranted.