Filing a petition on November 24, before US District Court for the Southern Districts of Indiana, Eli Lilly and company has alleged that Lupin and its US-based subsidiary

Lupin Pharmaceuticals Inc has infringed its intellectual property rights granted for anti-depressant drug Cymbalta.

According to the information available on the website of the district court for the southern districts of Indiana, the US drug giant has also filed complaint against Aurobindo Pharma USA INC, the US arm of Hyderabad-based Indian drug major Aurobindo Pharma.

Cymbalta, an anti-depressant drug whose patent will expire on June, 2013, has a total global sales of around $2 billion in Eli Lilly's portfolio. Till now, Eli Lilly and company has filed suits alleging patent infringement against six companies in United States of which three are Indian firms including Wockhardt.

The other three firms against which Eli Lilly and company has alleged patent infringement for its anti-depressant drug Cymbalta in US are Sandoz, Cobalt Laboratories and Impax Laboratories.

These six firms against whom Eli Lilly and company has filed suit have actually applied for marketing approval of copy version Cymbalta under an abbreviated new drug application.

According to the experts, litigation against generic applicants is very common in US and Eli Lilly and company's move is seen by the generic drugs makers as an attempt to delay the introduction of cheaper version of drugs in US which is the largest drug market globally.