Shire plc has filed a lawsuit in the US District Court for the Southern District of New York against Natco Pharma Limited (Natco) for infringement of two of Shire's patents: US Patent No 5,968,976 (976 Patent); and US Patent No 7,381,428 (428 Patent).

The lawsuit was filed in response to an ANDA (Abbreviated New Drug Application) filed by Natco seeking FDA approval to market and sell generic versions of Shire's 500 mg, 750 mg, and 1 g Fosrenol (Lanthanum Carbonate) products.

Under the Hatch-Waxman Act, because Shire filed its patent infringement lawsuit within 45 days of receiving Natco's Paragraph IV notification letter, the FDA must refrain from approving Natco's ANDA for 30 months, or until a district court decision finding that the patents are invalid or not infringed, whichever occurs earlier. The stay on generic approval will expire on April 26, 2012 unless terminated earlier.

Shire has asserted the '976 and '428 patents based upon information provided to it by Natco. Shire will continue to evaluate the situation throughout the litigation and will take all necessary actions to protect its rights to the fullest extent possible. Shire has a robust patent estate and is confident that it will protect the Fosrenol franchise.

Shire's strategic goal is to become the leading specialty biopharmaceutical company that focuses on meeting the needs of the specialist physician.