Cheminor unfazed by AstraZeneca patent infringement suit

Cheminor Drugs Ltd has termed the infringement suits filed by AstraZeneca Inc and Eli Lilly & Company as usual practice by multinational companies to sue applicants of generic equivalents. G V Prasad, managing director CDL, says such litigation is a normal practice when applicants file 'abbreviated new drugs applications' (ANDAs), including patent challenges. "Most of Cheminor's filings in the US are patent challenges, which call for litigation," according to him.

AstraZeneca has filed a lawsuit at the federal district court of New Jersey against the ANDA filed by CDL and Cheminor-Reddy Inc for a generic version of omeprazole, an anti-ulcer drug.

Astra Pharmaceuticals LP is marketing the anti-secretory drug in the US under the brand name Prilose and internationally as Losec. Omeprazole had a $2.9 billion dollar market in 1998, an increase of 25 per cent over 1997.

A similar suit was filed on 11 January 1999 by Eli Lilly against CDL for patent infringement of its $2.1 billion blockbuster drug Prozac (fluoxetine hydrochloride).

Though the patent rights for omeprazole expire on 5 April 2001, AstraZeneca, in its suit, contends that Reddy-Cheminor Inc infringes upon several other patents relating to Prosilec, which are valid until the year 2014. These include patents for the basic substance omiprazole, its formulations and methods of its usage.

CDL has filed six ANDAs individually and jointly with its three marketing partners in the US, and is in the process of filing nine more. The company has recently set up a modern Rs 50 crore plant in Hyderabad for manufacturing generic off-patent formulations.

Though the US FDA-approved formulations plant is ready to produce ranitidine 75 mg, plans were shelved due to the six-month extension of exclusive marketing rights granted to Glaxo Wellcome for this product.