Sigmapharm files ANDA for generic Hepsera

FOSTER CITY, Calif. A generic drug maker has filed an abbreviated new drug application for its version of a Gilead Sciences drug.

FOSTER CITY, Calif. A generic drug maker has filed an abbreviated new drug application for its version of a Gilead Sciences drug.

Sigmapharm is looking to receive regulatory approval from the Food and Drug Administration for generic Hepsera (adefovir dipivoxil). In a notice letter sent to Gilead, Sigmapharm alleged that two patents associated with Hepsera -- U.S. Patent Numbers 5,663,159 and 6,451,340 -- owned by Gilead Sciences are invalid, unenforceable and/or will not be infringed by Sigmapharm's manufacture, use or sale of the product described in its ANDA submission.

Gilead currently is reviewing the notice letter and has 45 days from the date of receipt to commence a patent infringement lawsuit against Sigmapharm. Such a lawsuit would restrict the FDA from approving Hepsera's ANDA for up to 30 months or until a district court decision that is adverse to Gilead, whichever occurs first.