The FDA has given Israel-based Teva Pharmaceutical and Ohio-based Roxane Laboratories the go-ahead to market generic versions of Pfizer's blockbuster antidepressant Zoloft, the agency said June 30, the same day Pfizer's patent expired.

U.S. sales of Zoloft (sertraline) -- the sixth highest-selling brand drug in the U.S. -- were more than $2.6 billion in 2005, the FDA said. Teva plans to launch its Zoloft equivalent in late July. Roxane has not yet announced when it will launch its version.

Israeli drugmaker Teva will market the drug in 25-, 50- and 100-mg tablets. Roxane will market a 20-mL liquid concentrate Zoloft equivalent (sertraline HCl). Sertraline tablets are indicated to treat depression while liquid sertraline is indicated to treat depression and some anxiety disorders.

Teva and Roxane were the first companies to file applications containing a Paragraph IV certification for the Zoloft products they each plan to market, and each received 180 days of marketing exclusivity for their products. A Paragraph IV certification claims the drug patent is invalid or would not be infringed on by the generic version of the drug.