Effect of Rituximab on Pulmonary Function in Bronchiolitis Obliterans Syndrome due to Graft-Versus-Host-Disease

Rituximab is an anti-CD20 monoclonal antibody that is used to suppress B-cell function in graft-versus-host-disease (GVHD). We sought to determine the effects of rituximab treatment on lung function in those patients with bronchiolitis obliterans syndrome (BOS) as a manifestation of GVHD. Thirteen patients were treated with rituximab with a diagnosis of BOS and a significant reduction in the forced expiratory volume in 1 s (FEV1) after hematopoietic stem cell transplantation (HSCT). The changes in their pulmonary function for 12 months following treatment with rituximab were followed, along with other intervention performed and daily average dosing of prednisone. Following rituximab administration, there was an improvement in the slope of decline in lung function from -5.12 ml/month prior to rituximab infusion to -0.31 ml/month after 3 months and to +2.27 ml/month 12 months later. Seven of the 13 patients had an increase in their FEV1 after treatment with rituximab. Additionally, the mean daily dose of prednisone decreased from 27 mg prior to rituximab treatment to 11 mg 12 months after treatment. Nine out of 13 patients survived 12 months after rituximab treatment. All of the patients with improvement in FEV1 following rituximab treatment were receiving concomitant extracorporeal photopheresis. Rituximab is safe with the potential to stabilize or improve lung function in patients with BOS after HSCT and should be considered as a treatment option in those patients.