Glaxo Fires Latest Shot in Patent Battle with Genentech over Therapeutic Molecule Antibodies

On September 20, Glaxo Smith Kline (Glaxo) sued Genentech for infringement of US patent numbers RE40,070 and RE41,555 in the District of Delaware. The patents claim methods of purifying monomeric IgG antibody using hydrophobic interaction chromatography. GSK alleges in its complaint that Genentech's production of therapeutic monoclonal antibody products, specifically Herceptin, infringes the patents. Herceptin is an important monoclonal antibody therapeutic used to treat HER2 positive breast cancer. The complaint is available here.

The lawsuit is the latest volley in an ongoing patent war between GSK and Genentech over recombinant monoclonal antibody technology. Most of the patents that have been asserted are directed towards general methodologies used in the production and formulation of monoclonal antibody therapeutics.

For example, in 1999 Glaxo sued Genentech for allegedly infringing US patent numbers 5,545,403 and 5,545,405 (both generally claiming methods of treatment using recombinant antibody glycosylated by Chinese hamster ovary (CHO) cells), and US patent numbers 5,654,403 and 5,792,838 (both directed towards methods of stabilizing antibody formulations using copper chelators). Glaxo alleged that the patents were infringed by Genentech's production of Herceptin and Rituxan, two cancer drugs that target breast cancer whose tumors over express the HER2 protein and CD20 positive, B-cell non-Hodgkin's lymphoma, respectively. A district court held for Genentech, finding all of the asserted Glaxo claims invalid and/or not infringed. The case settled while on appeal to the Federal Circuit.

In 2000, Glaxo sued Genentech for allegedly infringing US patent number 5,633,162, which claims methods of growing CHO cells in a serum-free medium. While the complaint does not specifically identify the allegedly infringing Genentech products, Genentech reported in a filing to SEC that it assumed that the lawsuit was directed towards Herceptin and Rituxan. This case settled early in the litigation.

In 2009, Glaxo received FDA approval to market Arzerra, an anti-CD20 approved for the same indication as Genentech's Rituxan (chronic lymphocytic leukemia). Thus, the two products can be viewed as direct market competitors, perhaps biosimilars (we are still awaiting guidance from FDA as to criteria for biosimilarity under the new biosimilarity legislation passed by Congress as part of healthcare reform).

In 2009, Glaxo filed a declaratory judgment action in the Southern District of Florida seeking a judgment of invalidity, unenforceability and noninfringement with respect to Genentech's patent number 6,331,415. This patent is widely referred to as the “Cabilly II” patent, and came out of a highly publicized interference between Genentech and Celltech. The patent broadly covers the co-expression of immunoglobulin heavy and light genes in a single host cell. Genentech has been quoted as stating that the patent is "the backbone of recombinant antibody production in the biotech industry." Genentech has already asserted the patent against MedImmune and Centocor, alleging that those companies’ production of monoclonal antibodies products Synagis, ReoPro and Remicade infringe the patent. The litigation between Genentech and MedImmune resulted in a Supreme Court decision on standing of a patent licensee to bring a declaratory judgment action action challenging the patent. Genentech successfully moved to have the litigation transfer to the Central District of California, where the Centocor and MedImmune litigations are located.

In 2010, Genentech (along with Biogen Idec, its partner in the marketing of Rituxan) sued Glaxo in the Southern District of California for allegedly infringing US patent number 7,682,612. The patent claims methods of treating chronic lymphocytic leukemia using an anti-CD20 antibody, and thus invalid would appear on its face to be infringed by Arzerra. This case is somewhat noteworthy, since it is the only one in which the patent is specifically directed towards an antibody recognizing a specific antigen (CD20), as opposed to the other patents all relating to general methods of antibody production and formulation.