Forest Laboratories
Forest Laboratories ()

Just days before its blockbuster merger announcement with Actavis, drug maker Forest Laboratories Inc. filed a lawsuit in federal district court in Delaware accusing several generic pharmaceutical manufacturers of infringing patents related to its exclusive treatment for Alzheimer’s disease.

The complaint, filed by Quinn Emanuel Urquhart & Sullivan on Feb. 14, is part of an effort by Forest Labs to protect its branded Alzheimer’s drug, Namenda. The suit targets Canada’s Apotex Inc.; India’s Cadila Healthcare; and New Jersey’s Par Pharamceutical Inc., among others.

It is unclear what impact, if any, this week’s announcement will have on the litigation. On Tuesday, pharmaceutical giant Actavis said it would buy Forest Labs for an estimated $25 billion in cash and stock. Reuters reported that Actavis had previously sought to sell its own generic version of Namenda.

The patents at issue in the suit relate to an updated version of the Alzheimer drug, which allows for medication to be delivered into the body on a time release, and is supposed to reduce potential side effects and allow for more effective administration to the patient. Forest Labs is the owner of one patent and the exclusive licensee for Alzheimer treatments of six others.

Forest Labs original patents for Namenda are set to expire next year. Several drug makers have already filed applications with the U.S. Food and Drug Administration for approval of a generic version, according to the complaint in Forest Laboratories v. Apotex Corp, 14-200.

The company insists the rival treatments, if approved, would infringe its newer patents for the time-release formulation.