Forest files fifth patent lawsuit to protect Viibryd

Forest Labs, a subsidiary of Actavis, has sued InvaGen for allegedly infringing four patents covering depression drug Viibryd, in what is the fifth related lawsuit.

The company filed a complaint at the US District Court for the District of Delaware on Monday (March 30).

It had previously filed four Viibryd-related actions at the same court last Friday (March 27), against Alembic, Apotex, Teva and Accord Healthcare.

InvaGen had filed an Abbreviated New Drug Application (ANDA) with the US Food and Drug Administration seeking approval to make and sell a generic version of Viibryd before the four patents covering the drug expire.

The asserted patents, US numbers 7,834,020; 8,193,195; 8,236,804; and 8,673,921, are owned by German pharmaceutical company Merck, which licenses them exclusively to Forest.

They are all due to expire in June 2022.

InvaGen said in a notice letter to Forest that the ANDA included a Paragraph IV certification asserting that the patents are invalid, unenforceable and will not be infringed by its generic version.

Forest has asked the court for a judgment that InvaGen’s ANDA filing was an act of infringement, and that the manufacture or sale of its generic drug will infringe the patents.

It has also asked for an order stating that any FDA approval of the proposed generic should not be granted until after the four patents have expired.

Finally, Forest requested a permanent injunction stopping InvaGen from making and selling the Viibryd generic.