A whole host of companies are preparing to flood the market with their generic versions of Pfizer’s blockbuster antidepressant Zoloft as the successful patent challenger, Israel’s Teva Pharmaceutical Industries, sees the 180 days of marketing exclusivity for its copycat drug come to an end.

Barr Laboratories’ Croatian-based subsidiary Pliva and Mylan Laboratories were the first firms to issue statements heralding the end of Teva’s exclusivity and their final approvals from the US Food and Drug Administration for their Abbreviated New Drug Application to manufacture and market generic Zoloft (sertraline). Both companies said that their versions of the drug, which brought in $166 million to Pfizer’s coffers in the fourth quarter, already down 79% as a result of Teva’s copycat, will be shipped immediately.

However this is just the tip of the iceberg as a number of Indian drugmakers, including the major generics players such as Ranbaxy, Dr Reddy’s and Cipla are poised to get their version of Zoloft out there once the tentative approvals they have from the FDA get the full green light.

As to where this leaves Teva is not clear as the firm recently filed infringement claims "against a number of finished dose companies" which are manufacturing their own versions of the antidepressant. Teva launched sertraline in August and in filing the complaint, mentioned four patents it holds covering processes of making the drug which have expiry dates ranging from November 2019 to April 2023. At the time, the Jerusalem Post named Novartis' generic unit Sandoz and India's Lupin as two of the firms in question.

If Teva wins in court, its rivals named in the lawsuit may be forced to pay out significant sums in compensation though possible legal ramifications would not appear to be putting any generic firms off at the moment.

- Meantime, Teva has been mentioned, along with Novartis, as being interested in buying a major stake in the Indian drugmaker Aurobindo Pharma, The Hindustan Times newspaper, which cited sources close to the company, said that the Hyderabad-based firm is in advanced stages of negotiations with the two companies.