Forest sues Lupin to protect $1.5bn Namenda

Actavis-owned pharmaceutical company Forest, along with US-based Adamas Pharmaceuticals, has sued Indian generic drug maker Lupin for infringing seven patents directed to its Alzheimer’s drug Namenda XR (memantine hydrochloride), a once daily version of Namenda.

Forest, which markets the drug in the US, holds one of the patents at suit. US patent 8,039,009 covers pharmaceutical compositions of Namenda’s active ingredient and is due to expire in 2029. Adamas Pharmaceuticals holds the remaining six patents, which cover methods for administering the drug.

The companies filed the case at the US District Court for the District of Delaware on Friday (August 15), in response to an Abbreviated New Drug Application (ANDA) submitted by Lupin.

In July, Lupin sent the ANDA to the US Food and Drug Administration for approval to make and sell memantine capsules in 7 mg, 14 mg, 21 mg and 28 mg strengths before the Namenda patents expire.

In its application, Lupin argued that claims in the seven patents are invalid, unenforceable, or will not be infringed by its generic products.

Forest said in its complaint that Lupin’s filing of the ANDA constitutes infringement of the six Adamas patents, although it does not allege that the ‘009 is infringed.

“To the extent that discovery in this action demonstrates that assertion of the ‘009 patent against the Lupin generic products is warranted, plaintiffs reserve the right to assert it,” Forest said in the complaint.

Forest also claimed that Par Pharmaceuticals infringed the patents by filing an ANDA for approval to make and sell 28 mg capsules of memantine.

It has asked for judgment that the companies have infringed the patents, and for monetary relief.

In February, Forest announced that it would discontinue Namenda to focus on its once daily version of the drug, Namenda XR, effective August 15, the day it filed its complaint of patent infringement.

In 2013, Namenda and Namenda XR generated sales of $1.5 billion.