Japan's drug major Takeda Pharmaceuticals has filed a Para IV patent infringement law suit against the Indian drug major Cadila Healthcare Ltd in District Court of New Jersey, US, for allegedly attempting to manufacture and market the generic version of its proton pump inhibitor brand Prevacid SoluTab, lansoprazole, delayed release orally disintegrating tablets in US.

The Takeda Pharmaceuticals America Inc, the US subsidiary of the Japanese firm, and the French pharma firm Ethypharm, S A, has filed the suit against Cadila Healthcare and its US subidiary, Zydus Pharmaceuticals (USA) Inc, alleging that the latter has infringed three US Patents, namely Patent number 5,464,632 ('632) for Rapidly Disintegratable Multiparticular Tablet, issued on December, 1995, patent numbers 6,328,994 ('994) and 7,431,942 ('942) for Orally Disintegrable Tablets, issued on December, 2001, and October, 2008 respectively.

Out of this, the patent '632 for lansoprazole is owned by Ethypharm and has granted an exclusive sublicence for commercial activities. As per the complaint filed by the firms, Zydus submitted Abbreviated New Drug Application (ANDA) to the US Food and Drug Administration (FDA) seeking approval to manufacture and market lansoprazole delayed release orally disintegrating tablets, 15 and 30 mg, prior to the expiration of the patent validity.

Prevacid SoluTab orally disintegrating tablets, which works by decreasing the amount of acid produced in the stomach, are used for preventing or treating certain types of ulcers, symptoms of gastroesophageal reflux disease (GERD) like heartburn and irritation of the esophagus. It is also used to treat conditions like Zollinger-Ellison syndrome, that cause the humab body to make too much stomach acid.

According to FDA records, the '632 has a patent validity at least to Nov 7, 2012, even as the patent nos '994 and '942 will have a validity to at least May 17, 2019. According to latest reports, which quotes figures from market research major IMS Health, annual sales of the drug is at around US$ 513 million in the US.

Zydus, in its notice related to the ANDA filing, opined that the patents related to the product are invalid or will not be infringed by the commercial manufacture or sales of the lansoprazole delayed release orally disintegrating tablet products described in ANDA. The complainants plead the Court to issue an order decreeing that Zydus and Cadila have infringed the relevant patents and the ANDA should not be approved before the expiry of the last of the patents-in-suit, including any extensions.

Takeda, in January, 2010, has lost an appeal of patent infringement suit against Teva Pharmaceuticals for the Prevacid SoluTab. The US Court of Appeals for the Federal Circuit in Washington, in January, upheld an earlier lower court decision that the Teva's version of drug does not infringe the patents (the '632, '994 patents, as well as the US Patent Nos. 4,628,098 and 5,045,321).

In November, 2009, the lower court - the US District Court of Delaware - said that the Teva's version of the drug used a different way to dissolve the medicine than is covered by the '632 patent. The court observed that the complainants failed to show that Teva infringed '321 patent even as they have dismissed allegations of any infringement of the '994 patent. The '098 patent for the active compound, lansoprazole, patent '098 has expired on May 10, 2009.