Teva and AstraZeneca want a consolidated class action lawsuit alleging they conspired to delay generic entry of AstraZeneca’s acid-reflux drug Nexium dismissed, arguing that Teva couldn’t have marketed its version sooner due to approval delays plaguing Ranbaxy, which has 180 days of generic exclusivity on the product.

The class action lawsuit alleges that AstraZeneca paid off Teva under the guise of a 2010 deal to settle Teva’s patent challenge against Nexium (esomeprazole magnesium). The plaintiffs, comprised of drug distributors, retailers and union health benefit funds, also are suing Ranbaxy and Dr. Reddy’s for similar alleged deals. Plaintiffs say those deals guaranteed no Nexium generic would arrive until May 27 of this year, which forced them to purchase the more expensive branded version for years more than they otherwise would have.

In a dismissal brief filed in Massachusetts federal court, AstraZeneca and Teva rely on recent rulings from the court to argue that generic market entry sooner would have been impossible.

They cite findings that Ranbaxy was entitled to 180-day generic exclusivity as the first-to-file an ANDA against Nexium, but was unable to launch before its licensed-entry date of May 27 because of “continuing, and well-documented difficulties with obtaining FDA approval.”

Ranbaxy’s biggest difficulty has been import bans on all five of its Indian manufacturing facilities. The company still has not entered the market with a generic Nexium product despite the passage of the May 27 entry date, Teva and AstraZeneca said.

AstraZeneca remains the only pharmaceutical company authorized to market Nexium’s active ingredient, according to the Orange Book.

By law, none of the other ANDA filers can get final FDA approval and launch until Ranbaxy does, AstraZeneca and Teva said. Nor is that exclusivity in danger until at least Sept. 30 due to Ranbaxy’s consent decree with the FDA that gave it until then to reach certain milestones, they added. — Bryan Koenig

Originally appeared in Drug Industry Daily, the pharmaceutical industry’s number one source for regulatory news and information. Click here for more information.