Allergan sews up a Namenda XR cushion with Amneal patent settlement

After scrambling to convert Namenda patients over to a newer, longer-lasting version of the med, Allergan ($AGN) certainly doesn't want generic competition to the updated version. And for now, it's dodged a bullet, by striking an accord with Amneal to keep its copy off the market for more than four years.

Allergan's Forest Labs subsidiary settled a Namenda XR patent fight with the New Jersey drugmaker, which appears to have first-to-file generics exclusivity on the drug. Under the pact, Forest gives Amneal a green light to launch its knockoff on Jan. 31, 2020.

Amneal has a choice, though--it can also choose to launch an authorized generic of the long-acting Alzheimer's drug if it waits until the same date in 2021.

Either way, the patent settlement gives Namenda XR some breathing room--which it needs, now that its predecessor is facing cheap competition from Dr. Reddy's and Mylan ($MYL). Allergan had planned to pull the original drug from the market--forcing patients over to XR before generics hit--until a court struck down that idea. But even without the so-called hard switch, Allergan managed to convert about half its patients over to the IP-shielded version, CEO Brent Saunders said in May.

Namenda XR isn't totally in the clear, though. "Similar patent infringement litigations" against "certain other companies" that have filed ANDAs are still pending in U.S. District Court in Delaware, Allergan said.

- read Allergan's release

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