Pfizer Files for Patent Office Review of Three Biogen Claims for Rituxan

Pfizer called for the invalidation of three Rituxan patents covering treatments for non-Hodgkin lymphomas last week, filing separate complaints with the PTO’s patent review board.

The three patents, owned by Biogen, were combinations of Rituxan (rituximab) and standard chemotherapies. The company called the claims unpatentable and requested inter partes review by the PTO’s Patent Trial and Appeal Board.

Rituxan, also known as MabThera, brought in over $7.3 billion in worldwide sales for Roche in 2016, through a co-marketing agreement between its subsidiary Genentech and Biogen. A CD20-targeting antibody, Rituxan was first approved by the FDA in 1997 to treat B-cell non-Hodgkin lymphomas resistant to chemotherapy.

Two of the three patents are also being challenged by Celltrion, whose rituximab biosimilar Truxima was approved in the European Union in February. Pfizer currently has its own biosimilar version under development for several indications.