Watson confirms patent challenge for generic Combigan

MORRISTOWN, N.J. Generic drug maker Watson Pharmaceuticals has applied for Food and Drug Administration approval for a version of a drug used to treat eye diseases, Watson said Tuesday.

Watson announced that subsidiary Watson Labs had filed for approval of brimonidine tartrate and timolol maleate ophthalmic solution in the 0.2%/0.5% strength. The drug is a generic version of Allergan’s Combigan, used to reduce pressure inside the eye, also known as intraocular pressure, in patients with glaucoma or ocular hypertension for whom current or previous therapies are ineffective.

The drug had sales of around $98 million during the 12-month period ended in July, according to IMS Health.

Allergan filed a patent infringement suit against Watson earlier this month in the U.S. District Court for the Eastern District of Texas in order to prevent Watson from marketing its version of the drug before the expiration of four patents covering Combigan, the last of which expires in January 2023, according to FDA records; the exclusivity period for the drug expires at the end of October of this year. Under the Hatch-Waxman Act, Allergan’s lawsuit places a stay on final FDA approval of Watson’s drug for 2.5 years, or until the two companies resolve the matter before the court.