Enzon files PEG patent infringement lawsuit against Roche

Enzon, Inc. (Piscataway, NJ) announced on September 5 that it has filed a lawsuit in Federal Court in New Jersey against Hoffmann-LaRoche, Inc. and Roche Laboratories, Inc. for infringement of Enzon's new U.S. Patent 6,113,906 by Roche's "PEGASYS," a pegylated alpha interferon-2a product. PEG refers to polyethylene glycol, which Enzon has used to improve drugs' stability.

This new Enzon patent, which has claims directed to "branched PEG," a form of Enzon's high-molecular-weight pegylation technology, was issued on September 5, 2000. Foreign patent applications corresponding to this U.S. patent are now pending.

This latest patent covering Enzon's PEG technology issued from the same family as Enzon's earlier U.S. Patent 5,643,575, which Enzon is currently asserting against Shearwater Polymers, Inc. (Shearwater), in federal court in Alabama. In the Alabama case, Shearwater asserted that the '575 patent is invalid on a number of grounds, including certain articles authored by Yamasaki and colleagues. The Yamasaki articles were considered by the U.S. Patent and Trademark Office during prosecution of the application for Enzon's new '906 patent, which was issued in spite of these references.

Enzon licenses a "pegylation" technology that differs from Schering-Plough's Pegintron (peginterferon alfa-2b), which is currently undergoing FDA review for treating hepatitis C. In May 2000, Schering-Plough received marketing authorization in the European Union for Pegintron for treating hepatitis C. Enzon believes that under its licensing agreement with Schering-Plough, it is entitled to royalties on worldwide sales of Pegintron as well as milestone payments.

Pegylation involves the chemical combination of polyethylene glycol (PEG) with protein and small molecule drugs to increase their circulation time in the body and decrease their immunogenicity. Enzon has several U.S. and foreign patent applications and issued patents covering this technology.

"We plan to vigorously pursue this case against Roche's infringement of our intellectual property rights," stated Peter G. Tombros, Enzon's president and chief executive officer. Schering-Plough announced that it "fully supports" Enzon's lawsuit against Roche.

Enzon sells two FDA-approved products that utilize its earlier pegylation technology; Oncaspar, is used to treat acute lymphoblastic leukemia, and Adagen, a treatment for a form of severe combined immunodeficiency disease.

For more information: Kenneth J. Zuerblis, VP of Finance at Enzon. Tel: 732-980-4717.

Edited by Angelo DePalma
Managing Editor, Pharmaceutical Online and Drug Discovery Online