Chimaeric anti‐CD20 monoclonal antibody (rituximab) in post‐transplant B‐lymphoproliferative disorder following stem cell transplantation in children

Post‐transplant lymphoproliferative disorder (PTLD) after haemopoietic stem cell transplantation is a serious complication that occurs in 8–22% of patients with high‐risk factors. We retrospectively investigated tolerance and efficacy of humanized anti‐CD20 monoclonal antibody (rituximab) as first‐line treatment in 12 children with B‐cell PTLD. At diagnosis, eight patients had tumoral involvement. The other four patients had fever, associated with raised Epstein–Barr virus (EBV) viral load and monoclonal gammopathy. Rituximab was given at the dose of 375 mg/m2 once a week by intravenous infusion (1–9 infusions). Only 1/48 infusions was associated with a grade 2 clinical adverse event. Eight out of 12 (66%) patients responded to the treatment and were in complete remission. All patients without tumoral involvement responded to the treatment. A rapid decrease in fever within 1 week was observed in all responders. Non‐responders did not show any clinical response during the first week. Tumoral involvement and immunodepression seemed to be more marked in non‐responders. Rituximab was an effective and well‐tolerated treatment of B‐cell PTLD. Early treatment before tumoral involvement seemed to be the most effective approach. Lack of rapid response should lead to intensification of PTLD treatment. Pre‐emptive treatment should be considered and evaluated in further longitudinal multicentre studies.