Memantine hydrochloride (Namenda) 5 mg and 10 mg Tablets: Lupin entered into licensing agreement with innovator

Indian Pharma Giant M/S Lupin Pharma has announced that it has settled the litigation with innovator Forest Lab and Merz Pharma, which was pending in Delaware District Court, Maryland District Court and District of Columbia w.r.t generic version of Memantine hydrochloride (Namenda) 5 mg and 10 mg tablets.

Innovator has listed following patent in Orange Book for Memantine hydrochloride 5 mg and 10 mg tablets and sued Lupin and other generic players for the infringement of the same:

US5061703 (Expiry: April 11, 2015): The patent covers a method for the prevention or treatment of cerebral ischemia comprising the step of administering, to a patient in need thereof, an effective amount of Memantine (The said patent has got five years of patent term extension as reported by us Here )


Under the terms of agreement, Lupin will have a license under the required patents to launch its generic Memantine hydrochloride (Namenda) 5 mg and 10 mg tablets in January 2015 or earlier in certain unspecified circumstances. Importantly, Lupin would be able to market generic version almost 3 months earlier from the patent expiry date.

Earlier, the various generic players like Barr Lab, Cobalt Lab, Lupin, Orchid, Teva Pharma, Upsher-Smith Lab, Genpharm, Sun, Ranbaxy and Wockhardt filed ANDA with Paragraph patent IV certification against ‘703 patent. Subsequently, innovator sued various generic players for the infringement of ‘703 patent in U.S. District Court for the District of Delaware. Also, innovator sued Lupin in Delaware District Court, Maryland District Court and U.S District Court for the District of Columbia.

Earlier in September, 2009, the chief judge honorable G.M. Sleet of U.S. District Court for the District of Delaware has signed off on a request to dismiss M/S Upsher-Smith Lab (and 3 other generic players like Wockhardt, Amneal Pharmaceuticals, Apotex) from a patent infringement lawsuit that innovator Forest Labs and Merz Pharma brought to thwart the generic challenge to the Alzheimer's drug Memantine (Namenda) hydrochloride 5 mg and 10 mg tablets. Also in Oct, 2009, generic player Sun Pharma has agreed to launch generic version after the expiry of ‘703 patent.

Further, generic players like Orchid, Mylan and Cobalt are still in litigation with innovator for this product.

The generic players were not able to invalidate the method of use patent of this billion dollar molecule, till date. Further, 3 months earlier market entry (from patent expiry) is a favorable situation for Lupin to consolidate it’s generic version before further generic erosion after the patent expiry.