Mayer Brown, a leading global law firm, secured a victory before the US Court of Appeals for the Federal Circuit on behalf of Glaxo Group Ltd. and GlaxoSmithKline (GSK) in a patent infringement suit brought by Biogen Idec Inc. and Genentech Inc. In the suit, the plaintiffs alleged that GSK’s monoclonal antibody cancer treatment, ARZERRA®, infringed their patent relating to the treatment of chronic lymphocytic leukemia (CLL) through administration of an anti-CD20 antibody. ARZERRA® is the first FDA approved fully human monoclonal antibody for the treatment of CLL and competes with Genentech’s cancer treatment Rituxan®.

In the April 16th decision, the Federal Circuit affirmed the US District Court for the Southern District of California’s claim construction finding that Biogen Idec made a clear and unmistakable disclaimer and that the term “anti-CD20 antibody” was limited to Rituxan® and antibodies that bind to the same portion of the CD20 antigen with similar affinity and specificity as Rituxan®. Judge Reyna, writing for the majority, stated “[w]hile the applicants may not have repeated the examiner’s language verbatim et literatim, it is clear that they were limiting their invention to what the examiner believed they enabled: antibodies that have a similar specificity and affinity for the specific epitope to which Rituxan® binds.” Thus, ARZERRA® is excluded from the scope of the asserted claims and does not infringe United States Patent No. 7,682,612.

The Mayer Brown Intellectual Property litigation team, which included New York partners Lisa Ferri and Brian Nolan and Chicago partner Vera Nackovic, handled the district court litigation and the appeal to the US Court of Appeals for the Federal Circuit. Ms. Ferri argued at the Federal Circuit on behalf of GSK.