The U.S. Court of Appeals for the District of Columbia Circuit ruled today that Teva Pharmaceuticals Ltd of Israel and Ranbaxy Laboratories Ltd of India have the exclusive right to sell the generic version of the anti-cholesterol statin drug Zocor (simvastatin) for 180 days following the expiration of the Merck patent in June 2006. Teva and Ranbaxy had been the first companies to apply for Food and Drug Administration approval of their generic versions of Zocor (the companies applied for different dosage levels). The FDA had argued to the Court that the six month exclusivity period is only available to generic drug manufacturers that challenge the name brand manufacturer’s patent rights in court. In this case, the FDA had approved Merck’s application to delist their Zocor patents from the FDA’s database.

The Court disagreed with the FDA, holding that

the FDA’s requirement that a generic manufacturer’s patent challenge give rise to litigation as a condition of retaining exclusivity when a patent is delisted is inconsistent with the Act, which provides that the first generic manufacturer to file an approved application is entitled to exclusivity when it either begins commercially to market its generic drug or is successful in patent litigation.

The six month exclusivity period is lucrative for generic manufacturers particularly in the case of a blockbuster drug like Zocor. Merck continues to sell brand name Zocor at a price that is lower than that charged before its patent expired. Merck also has made a contract with Dr. Reddy’s Laboratories Ltd. of India to sell a so-called authorized generic version of Zocor.

A copy of the opinion in Ranbaxy Laboratories v. Leavitt, No. 06-5154 is available here.