Ranbaxy Laboratories’ claim to the 180-day exclusivity of its generic version of Merck & Co.’s cholesterol-cutting drug was supported by the U.S. Court of Appeals for the District of Columbia Circuit. The appeals court affirmed an earlier district circuit holding on Simvastatin, preserving the exclusivity period when patents are delisted from the FDA Orange Book.
Earlier, Merck delisted two patents on Zocor® (Simvastatin), which the FDA interpreted as eliminating Ranbaxy's 180-day exclusivity on the 80-mg strength of Simvastatin tablets. Ranbaxy challenged this decision on the basis that it was inconsistent with the Hatch-Waxman Act.
After the district court’s decision, Ranbaxy launched the 80-mg Simvastatin tablets with 180-day exclusivity in June 2006. In 2005, Merck’s Zocor sales totaled $4.4 billion. Currently, Ranbaxy has over 60% of the market share for the 80-mg strength of Simvastatin tablets, according to the company.