Bayer unit sues Abbott over Humira arthritis drug

Dec 31 (Reuters) - Bayer Healthcare LLC, a unit of Bayer AG (BAYG.DE) filed a patent-infringement lawsuit in a U.S. court against Abbott Laboratories (ABT.N) relating to the drug Humira, Abbot's top-selling product.

In a suit filed on Dec 24 in the U.S. District Court for the Eastern District of Texas, Bayer Healthcare said Abbott's drug infringes on a 1997 Bayer patent "Human Anti-TNF Antibodies." The patent covers antibodies that fight a protein called "tumor necrosis factor" (TNF), that causes inflammation.

Bayer Healthcare asked the court to determine that Abbott infringed on the patent and to award damages, the court filing showed.

Abbott could not be immediately reached for comment.

Humira is used to treat certain patients with arthritis, psoriasis, Crohn's Disease and a form of arthritis called ankylosing spondylitis. (Reporting by Ajay Kamalakaran in Bangalore; Editing by Kim Coghill)