AstraZeneca bolsters Nexium lawsuit against Lupin alleging violation of 3 new patents

India’s Lupin continued to defend its position on Nexium generic even as AstraZeneca strengthened its case by roping in more patents to the lawsuit alleging infringement of esomeprazole magnesium product’s IP rights.

Lupin, which has been sued by AstraZeneca on alleged violation of certain patents covering Nexium formulation, has submitted an appeal to the District Court of New Jersey declaring that the company will not be infringing any of the patents by manufacturing and sell esomeprazole magnesium delayed release capsules (Nexium) in the US market.

Lupin Ltd has not infringed any of the patents owned by AstraZeneca through seeking marketing approval for its generic version of gastric reflux disease drug Nexium (esomeprazole magnesium delayed release capsules) in US, the Indian generic firm asserted in declaratory statement to the court.

Lupin also argued that the three new patents — Nos.6, 147, 103; 6,166, 213; 6, 191, 148 –listed by AstraZeneca in its new lawsuit belong to Merck Inc as per records available with US PTO.

AstraZeneca, however, informed US FDA that “a claim of patent infringement could reasonably asserted if a person not licensed by the owner engaged in the manufacture and use or sale of esomeprazole magnesium formulations.”

Formulations of esomeprazole magnesium (Nexium) is protected by 11 patents listed in the Orange Book, AstraZeneca said.

AstraZeneca started legal proceedings against Lupin by filing a lawsuit in the district court of New Jersey alleging that Lupin’s abbreviated new drug application (ANDA) has infringed five of its United States Patent Nos. 5,714,504 (’504), 5,877,192 (’192), 6,875,872 (’872), 6,369,085 (’085), and 7,411,070 (’070) in October 2009 not including the new ’103,’213 and ’164 patents.

Lupin answered that all the patent claims including ’103, ’213 and ’164 are invalid and counterclaimed for a  declaratory judgement in December 2009.

Following this, AstraZeneca moved court again in January 2010 to spoil Lupin’s counterclaims arguing that Lupin failed to join a necessary and indispensable party — Merck, the owner of ’103, ’213 and ’164 and therefore the court lacked jurisdiction.

In its new petition seeking a declaratory judgment favoring the company declaring the invalidity of the three new patents, Lupin also pleaded the court to be awarded fees and costs spent defending this litigation.

Lupin submitted an abbreviated new drug application designated ANDA No. 91-324 and Drug Master Files (DMF) seeking FDA’s approval to manufacture commercially esomeprazole magnesium delayed release capsules in 20 mg and 40 mg strengths under para IV certification.

Lupin’s ANDA seeking US FDA’a approval to commercially manufacture and use drugs which contain esomeprazole as active ingredient constitutes a violation because the patents ’504, ‘192, ’872, ’085 and ’070 patents are still in force, AstraZeneca alleged in the lawsuit.

AstraZeneca’s ’504 patent entitled “Compositions,” was issued on February 3, 1998 to Astra Aktiebolag claims pharmaceutical formulations comprising alkaline salts of esomeprazole (including esomeprazole magnesium) and methods of using esomeprazole magnesium. The ’504 patent will expire on February 3, 2015 and pediatric exclusivity relating to the ’504 patent expires on August 3, 2015.

The ’192 patent,  refers to “Method For The Treatment Of Gastric Acid-Related Diseases And Production Of Medication Using (-)Enantiomer Of Omeprazole,” was issued on March 2, 1999 to Astra Aktiebolag, will expire on November 27, 2014. So is AstraZeneca’s ’872 patent, referring to esomeprazole magnesium is valid still November 27, 2014.

While AstraZeneca’s ’085 and ‘070 patents have validity till November 25, 2018, the lawsuit claimed.

However, Lupin in the Notice of Certification under para IV, 21 U.S.C. Section 355(j)(2)(A)(vii), said that the ’504 patent, “is invalid or will not be infringed by the manufacture, use, or sale of the new drug for which the application is submitted”

Nexium is currently one of the largest selling drugs in the world. Between the launch of esomeprazole in 2001 and 2005, Nexium has cloked AstraZeneca sales of about $14.4 billion.

Nexium is indicated for treatment of gastroesophageal reflux disease (GERD), healing of erosive esophagitis (EE).

Nexium 40 mg and Nexium 20 mg are indicated for short-term treatment (4 to 8 weeks) in healing and symptomatic resolution of diagnostically confirmed EE.

Nexium 20 mg is indicated for the treatment of heartburn and other symptoms associated with GERD.

Nexium is indicated for the short-term treatment (up to 8 weeks) of GERD (symptomatic GERD and healing of EE) in patients 1 to 17 years of age.