Rituximab dosing in B cell lymphoma

Rituximab has been extensively used in the treatment of CD20-expressing B cell neoplasms in the last two decades. Despite that, its dose and scheduling are still being questioned as they are inadequately supported by data. Our retrospective study of patients with indolent B cell lymphoma showed that older males and patients with higher weight had worse outcomes when treated with first line rituximab-containing chemotherapy, probably due to faster rituximab clearance. This suggests that a subset of patients with indolent B cell lymphoma may be sub-optimally dosed with rituximab as commonly administered. These results are in line with other studies in aggressive lymphoma where rituximab pharmacokinetics were shown to be affected by gender, age and weight and can affect outcomes. Our study also highlights the challenge of presenting the newer anti-CD20 monoclonal antibodies as intrinsically superior to rituximab when they are given at higher dose and more frequent administration.