Risk Reduction of Chronic Graft Versus Host Disease by Anti-CD20 Treatment (Rituximab).

Introduction:

Chronic graft versus host disease (cGVHD) occurs in 30–50% of adults transplanted by non-myeloablative (reduced intensity conditioning) allogeneic transplant, whereas it is rare in children. The syndrome complex manifests itselves as auto-immune disease. Dysregulation of B-cell function has also been reported in auto-immune diseases. This is a rationale for B-cell depletion.

We considered that B-cell depletion might have a therapeutic effect in cGVHD and reduce the risks associated with cGVHD. Based on these assumptions we applied risk reduction principles and defined a plan for cure of cGVHD.

Methods:

To identify the risks associated with B-cell depletion in cGVHD we performed a medline search on anti-CD20 or B-cell depletion or rituximab and cGVHD. The publications were analyzed and those applicable to the topic evaluated. Clinical research methods were applied to define a plan for risk reduction of cGVHD.

Results:

The medline search revealed that rituximab was used for B-cell depletion in cGVHD and in auto-immune diseases. In advanced cGVHD complete and partial remissions of a variety of manifestations of cGVHD were reported. Complete remissions could also be induced early during the disease course of single manifestations of cGVHD not responsive to immune suppressive treatment or as initial treatment. The dose of rituximab varied from 1 to 4 weekly courses of rituximab 375 mg/m², with repetitions of this schedule in advanced disease to induce complete response. During reported follow-up responding manifestations did not recur. Rituximab treatment was well tolerated with appropriate anti-allergic prophylaxis. The results support the concept that anti-CD20 treatment might cure cGVHD manifestations at first diagnosis; it is too early to define whether it also serves as prophylactic for development of new manifestations. The observations were discussed with the company marketing rituximab and a study plan was designed. This study plan is being discussed with study centers for risk reduction of cGVHD by rituximab. The risk reduction plan will be presented