Wyeth and its Swiss partner Nycomed have announced the launch in the USA of a generic version of the blockbuster Protonix in the latest stage of a battle with Teva Pharmaceutical Industries concerning the patent status of the antiulcerant.

Wyeth says it is launching its own copy of Protonix (pantoprazole) in response to Teva’s decision taken near the end of December to sell its version in the USA. Since the latter firm received Food and Drug Administration approval for generic Protonix in August, thus obtaining 180 days of market exclusivity, the companies have been involved in a patent-infringement lawsuit over the treatment.

After that, a New Jersey court denied Wyeth's and Nycomed's motion for a preliminary injunction and Teva prepared for launch. However, the Israeli-headquartered firm only shipped the drug for two days, starting on December 21, before Wyeth announced its plans to sue. This was followed by a deal which saw Teva agree to call a 30-day halt to shipments so that the problem could be solved in discussion with Wyeth and Nycomed. This ‘standstill” agreement was extended up to January 31.

It would appear that little progress was being made to end the ceasefire so Wyeth has started selling generic pantoprazole which will be distributed by Prasco. The US major’s chief executive Bernard Poussot said that “compound patents, like that infringed by Teva, represent the foundation of pharmaceutical innovation, a critical underpinning in bringing important new medicines to patients".

He claimed that the Protonix compound patent is strong “and we will vigorously pursue our litigation” against Teva and other infringing generics, such as one that India’s Sun Pharmaceuticals hopes to start selling. “Going forward, we will continue to seek an injunction against any infringement of this patent, as well as monetary damages, including lost profits, from Teva," Mr Poussot concluded.

Teva has responded by saying that Wyeth's launch of an authorised generic product renders the standstill agreement void. The patent on Protonix expires on July 19, 2010, according to Wyeth, and could be extended further if approval is given for paediatric use of the drug.