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Pfizer announces positive top-line results for potential biosimilar to Rituxan® / MabThera®

Pfizer Inc. has announced that REFLECTIONS B3281006, a comparative safety and efficacy study of PF-05280586 versus MabThera® (rituximab-EU), met its primary endpoint. PF-05280586 is being developed by Pfizer as a potential biosimilar to Rituxan® (rituximab-US) / MabThera® (1). The trial demonstrated equivalence in overall response rate (ORR) for the first-line treatment of patients with CD20-positive, low tumor burden, follicular lymphoma.
“We are pleased to report on our fifth proposed biosimilar monoclonal antibody (mAb) with positive study results. These results reinforce the potential of our proposed rituximab biosimilar in providing a safe and effective treatment option for patients,” said Amrit Ray, MD, global president, Pfizer Essential Health Research and Development. “As a global leader in novel biologics, and with one of the broadest global portfolios in oncology, we are delivering on our commitment to advancing high-quality medicines for the millions of patients with cancer around the world today and in the future.”
Pfizer’s biosimilars pipeline consists of seven distinct biosimilar molecules in mid to late stage development, with three of these in oncology, as well as several others in early stage development.

About the REFLECTIONS B3281006 Study

REFLECTIONS B3281006 is a randomized, double-blind clinical trial evaluating the efficacy, safety, pharmacokinetics and immunogenicity of PF-05280586 versus MabThera® (rituximab-EU)for the first-line treatment of patients with cd20-positive, low tumor burden, follicular lymphoma. The primary endpoint measure, ORR, is defined according to the revised response criteria for malignant lymphoma [Time Frame: Week 26]. Results of the study will be presented in full at a future medical meeting or summarized in publication.
More information about the PF-05280586 REFLECTIONS B3281006 study can be found at

About PF-05280586

PF-05280586 is a monoclonal antibody (mAb) that is in development as a potential biosimilar to Rituxan®/MabThera®. Rituxan®/MabThera® is indicated for the treatment of patients with certain types of CD20-positive non-Hodgkin’s lymphoma; CD20-positive chronic lymphocytic leukemia; rheumatoid arthritis; granulomatosis with Polyangiitis and Microscopic Polyangiitis; and other region-specific indications.
PF-05280586 is an investigational compound and has not received regulatory approval in any country. Biosimilarity has not yet been established by regulatory authorities.