The Mumbai-based Lupin Ltd and its US subsidiary, Lupin Pharmaceuticals, have to face one more patent litigation in US, as the Guardian II Acquisition Corporation, the subsidiary of US-based Oscient Pharmaceutical Corp has filed a lawsuit against the company for patent infringement of its lipid regulating drug, Antara capsules.

The lawsuit was filed in the United States District Court for the district of Maryland by Guardian II Acquisition Corporation, and its licensor, Ethypharm SA, accusing infringement of US Patent No 7,101,574 (574 Patent) covering Antara (fenofibrate) capsules.

The suit was filed against the Para IV filing of Lupin, which has moved with an Abbreviated New Drug Application (ANDA) with US FDA in accordance with 21 USC 355(j)(2)(B)(iv) to market a generic version of Antara prior to the expiry of the '574 Patent in August 2020.

According to the Hatch-Waxman Act, final FDA approval of the generic drug product will be stayed until the earlier of 30 months from the date of receipt of the Paragraph IV certification notice or a court decision finding that the '574 Patent is either invalid, unenforceable or not infringed by Lupin's proposed generic product, informed Oscient Pharma officials.

However, Lupin officials said that the lawsuit on ANDA filings is always expected by generic companies in the current situation. "It's quite natural that the innovator company will file a suit against the generic company to stop ANDA certification. Our policy is not to comment on the patent lawsuit in public," said a Lupin source.

Unless Lupin receives a tentative approval of its generic version of Antara from the FDA, it cannot lawfully launch its generic version of Antara in the US until it receives final approval.

Ethypharm had received notice of a Paragraph IV certification on behalf of Lupin on 3 December 2008, advising of the submission of an ANDA with the FDA for Antara.

Lupin Pharmaceutical, Inc is the third fastest growing generic company in US according to IMS statistics. The company has a strong presence in the generic market and the growth is expected to continue in near future, added Lupin source.

Oscient Pharmaceuticals Corporation is a commercial-stage pharmaceutical company marketing the fenofibrate capsules, a cardiovascular product. Antara is indicated for the adjunct treatment of hypercholesterolemia (high blood cholesterol) and hypertriglyceridemia (high triglycerides) in combination with diet.