Background: Approval of the first monoclonal antibody against CD20-antigen, rituximab, heralded the new era of targeted therapy in hematology. Today there are many companies all over the world which have rituximab biosimilar at different stages of development. BIORIX is among the first clinical studies to demonstrate clinical comparability of rituximab biosimilar to innovator rituximab in patients with indolent non-Hodgkin's lymphoma. Aims: Evaluation of pharmacokinetics, pharmacodynamics, safety and efficacy of BCD-020 (rituximab biosimilar, BIOCAD, Russia) used as monotherapy in patients with indolent B-cell non-Hodgkin's lymphoma in comparison with the parameters of innovator rituximab (RTX). Methods: 92 patients (aged 18 years and older with diagnosed CD20-positive follicular non-Hodgkin's lymphoma, stage II-IV by Ann Arbor, 1-2 histologic grade, or marginal zone lymphoma) were enrolled into the study. Patients were randomised in 1:1 ratio to receive 375 mg/sq.m of BCD-020 or RTX omore...