Merck arm sues Sun over cancer drug

Schering Corporation, part of multinational pharma company Merck & Co, and London-based Cancer Research Technology Ltd have sued Sun Pharmaceutical for allegedly infringing patent rights on the world's largest selling brain cancer drug, Temodar.

The case, filed against Sun Pharma and its UAE-based subsidiary, Sun Pharma Global FZE, last week with the district court for New Jersey, seeks to prevent Sun Pharma from launching generic or reverse-engineered versions of the drug (temozolomide capsules) in 5mg, 20mg, 100mg, 140mg, 180mg and 250mg dosage forms, said the court document verified by Business Standard.

Temodar, which Merck acquired through the acquisition of Schering-Plough last year, has annual global sales of about $1 billion. It has sales of about $380 million in the US market.

The suit is in response to an abbreviated new drug application (Anda) filed by Sun Pharma with the US Food and Drug Administration (FDA), seeking to market its generic version, and Sun's letter to Merck dated August 3, informing of its plans to launch the drug before patent expiry.

The various dosages of the drug were approved by the FDA in August 1999 and October 2006. The drug has patent protection in the US till August 11, 2013.

Sun's move to challenge the patent rights of Temodar assumes significance, as the world's leading generic company, Israel's Teva Pharmaceutical-owned Barr Laboratories, had succeeded early this year in invalidating patent rights of the same drug. So far, no other company is known to have challenged the patent of Temodar, said experts.

Such patent litigation is common in generic drug business in the US. According to the US rules for generic drug launches, the generic company which files a patent-infringing Anda has to be sued by the innovator within 45 days to prevent the FDA from approving the generic for the next 30 months. In most such cases, the companies settle the litigation out of court.