New Delhi, Oct. 16: Generic drug manufacturing companies have had a poor run since 2004 in major litigation challenging patents in international courts.

But analysts feel that the recent reversals are unlikely to deter these companies from reducing the number of patent challenges they file. This is because if they win even a few of the many cases they file, it will bolster their bottomlines significantly.

During the period, as many as 35 “best selling” drugs of traditional pharma companies were scheduled to go off-patent. The current sales value of these drugs is estimated to be in the range of $35 billion.

Generic drug refers to a copy of an original product whose patent has expired.

Analysts say that the patent portfolios of some of the traditional pharmaceutical companies indicate that their in-house technical competence are inadequate to meet the threat from global generic drug manufacturers. Firms such as Ranbaxy are fiercely targeting the large domain of off-patent drugs.

Patent litigation has now become an integral part of the global generic drug business, because of extremely high stakes.

Ranbaxy, the country’s biggest pharmaceutical company, has been spending about $20 million annually for litigation in patent challenges. Analysts said generic drug manufacturers would not shy away from forking out money because the gains in case of a win would be too big.

Ranbaxy recently lost a key patent litigation against Pfizer, the world’s largest drug company, over the latter’s best-selling anti-cholesterol drug, Lipitor. Effectively, this means that Ranbaxy cannot introduce a cheap generic version of the drug in the market until the patent of the original expires in 2011.

A report on Asia Pacific markets prepared by brokerage and research firm CLSA pointed out that 2004 was a particularly bad year for generic companies in terms of patent litigation. It said of the 11 key patent litigation last year, there were nine losses and only two wins for the generic drug companies.

In fact, during the last six months, Ranbaxy and Dr Reddy’s have lost two key patent challenges. Dr Reddy’s has lost its challenge against Eli Lilly over the schizophrenic drug ? Zyprexa ? in April. The Lipitor ruling in the UK (against Ranbaxy) is the next big disappointment for the Indian generic drug industry.

Dr Reddy’s lost two cases last year ? one is over Lamisil against Novartis and other over Norvasc against Pfizer. Another Asian drug manufacturer, Teva of Israel, lost two cases last year against Glaxo Smithkline and Pfizer.

The trial against Ivax Corp and India’s Cipla Limited over a drug formulation, called Lexapro, is scheduled to begin in December.

The challenge will be heard in Wilmington, Delaware, in the US before the US District Judge Joseph Farnan ? the same judge in the hearing of Ranbaxy’s challenge against Pfizer’s Lipitor.