The FDA and a federal district court have removed all obstacles for Israeli company Teva and Indian company Ranbaxy to begin marketing their generic versions of Merck's $4.4 billion cholesterol drug Zocor, the drugmakers said June 23, the day Merck's patent expired.

Teva will market generic Zocor (simvastatin) in 5-, 10-, 20- and 40-mg tablets, and Ranbaxy will market an 80-mg tablet. Both companies said they will be launching their products immediately.

The District Court for the District of Columbia denied an eleventh-hour request by Sandoz to prevent the FDA from approving any generic version of Zocor until the court ruled on Sandoz's motion to have the FDA approve its application.

Also on June 23, the FDA granted final approval -- and 180 days of marketing exclusivity -- for Teva's and Ranbaxy's generic Zocor, a move the head of the FDA's Office of Generic Drugs, Gary Buehler, called "another example of our agency's efforts to increase access to safe and effective generic alternatives as soon as the law permits."

But in October 2005, the FDA decided Ivax -- now part of Teva -- and Ranbaxy should not receive exclusivity because Merck withdrew the two patents for which the drugmakers had filed Paragraph IV applications to market generic Zocor. Paragraph IV challenges contend a brand patent is invalid or that the generic product would not infringe on the patent, and can only be launched against patents listed in the FDA's Orange Book. In April, the Columbia district court ruled the FDA's action was "unlawful" and sent the issue back to the agency for review. The FDA has appealed the district court's decision to the United States Court of Appeals.