Ranbaxy Laboratories said Wednesday that the United States Court of Appeals for the District of Columbia Circuit has affirmed an earlier District Circuit holding on Simvastatin, preserving 180-day exclusivity when patents are de-listed from the FDA Orange Book.

Earlier, Merck had de-listed two patents on its branded cholesterol-reducing drug, Zocor (Simvastatin), which the U.S. Food and Drug Administration interpreted as eliminating Ranbaxy’s 180-day exclusivity on 80-milligram strength Simvastatin tablets.

Ranbaxy challenged the decision on the basis that it was inconsistent with the Hatch-Waxman Act. The Generic Pharmaceutical Association (GPhA) filed an amicus brief supporting Ranbaxy’s position. The District Court agreed and Ranbaxy launched 80 mg Simvastatin tablets with 180-day exclusivity in June 2006.

“We are pleased with this decision, for both Ranbaxy and the generic pharmaceutical industry,” said Jay Deshmukh, senior vice president of global intellectual property at Ranbaxy.

“This [decision] preserves the exclusivity of innovative generic pharmaceutical companies who expend significant effort and finances to introduce affordable generic medicines to the U.S. healthcare system,” he added.

The FDA’s Office of Generic Drugs has found Ranbaxy’s 80 mg Simvastatin tablets to be bioequivalent and hence therapeutically equivalent to Merck’s listed drug Zocor tablets in its 80 mg strength.

According to March 2006 data from IMS, total annualized sales of Simvastatin were $ 4.6 billion, out of which the 80 mg strength accounted for $513 million.

Ranbaxy currently has over 60 percent market share for the 80 mg strength of Simvastatin tablets.