Pfizer Inc. has recently started the clinical trials of its biosimilar rituximab program. The Phase I/II trial will be conducted in rheumatoid arthritis patients comparing the pharmacokinetics, pharmacodynamics and safety to that of different versions of rituximab sold in the EU and US.
The trial, REFLECTIONS B328-01, which started in March this year will be conducted globally in 210 patients with moderate to severe rheumatoid arthritis who are being treated with methotrexate. The patients will receive two intravenous treatments with either PF-05280586 or Rituxan or MabThera. Pfizer expects the study to be finished in December 2013.
Rituximab, sold under different brand names in the US and other parts of the world is a blockbuster biologic of Biogen Idec and Genentech (Roche). The product is approved to treat Non-Hodgkin’s lymphoma, chronic lymphocytic leukemia and rheumatoid arthritis in the EU and US, plus it is approved to treat diffuse large B cell lymphoma in the EU. Rituximab is also used for other types of lymphoma (e.g. Mantle Cell lymphoma) in certain parts of the world.
Rituximab, like many other blockbuster monoclonal antibodies, is under the attack of several biosimilar manufacturers. Celltrion of South Korea, Sandoz, the generics unit of Novartis, Teva of Israel and Merck has also started clinical trials of their own rituximab biosimilars.