Israeli drugmaker Teva Pharmaceutical Industries has launched the first generic version of Pfizer’s antidepressant Zoloft in the USA, allowing it to tap into a market worth in the region of $3 billion a year.

Teva was the first generic company to file for US regulatory approval to sell a generic version of Zoloft (sertraline), so it will have a 180-day period of market exclusivity for its product.

The Israeli firm said sales of Zoloft were $3.1 billion in the 12 months ended June 2006. In the first six months of this year, Pfizer reported total Zoloft sales of $1.49 billion, down 9%, with the USA accounting for $1.3 billion of that total.

Pfizer has launched its own generic version of Zoloft, via its Greenstone subsidiary, in a move that reinforces suggestions that the research-based drug industry is increasingly using price as a defensive measure against generic incursions.