AZ files FDA lawsuit over generic Seroquel

 AstraZenca’s lawsuit against the US FDA over its decision not to block the entry of generic versions of Seroquel and Seroquel XR (quetiapine fumarate) has been called a gamble.

AZ claims the FDA cannot approve any generic versions of the blockbuster brands that lack specific label safety warnings – which the pharma company holds exclusive rights to.

But Ana Nicholls, Healthcare Analyst at the Economist Intelligence Unit, says the move could backfire and end up damaging AZ’s relationship with the US health regulator.

The FDA denied a Citizen Petition filed by the pharmaceutical company on March 7th. AZ requested in September 2011 that generic versions should not be allowed to enter the market until December 2nd 2012, when data exclusivity expires.

But the Agency’s denial of the Petition has led to AZ saying it will “vigorously defend its legal rights”.

It is now seeking an injunction preventing the FDA from granting final marketing approval of generic versions until the start of December or, alternatively, until a federal court has had the opportunity to review the FDA’s action regarding the pending generic marketing applications.

Generic competition cost the company almost $2bn in revenue last year, it calculates. Seroquel generated sales in the US worth $3.3bn in 2011 and could earn additional revenue of $650 million if AZ gets its way.

If the lawsuit is successful, Ana Nicholls predicts the move may be used by other pharmaceutical companies looking to protect or extend patent exclusivity. “If AZ does succeed in its argument over labelling requirements and data exclusivity rights, then this might give it (and other companies) another way of extending protection for drugs that are coming off patent,” she said.

“Other companies have tried different tactics – Pfizer, for example, struck exclusivity deals with pharmacy benefits managers to protect sales of Lipitor after its US patent expired late last year.

“But with the mood in the US firmly against attempts by patented drug-makers to block generic competition, the likelihood of AZ winning its case seems remote, raising the question of how much its lawsuit may damage its relationship with the FDA.”

The patent covering the active ingredient in Seroquel and Seroquel XR expired in September 2011, with paediatric exclusivity expiring on 26 March 2012. Seroquel XR is covered by a formulation patent that expires in May 2017, with paediatric exclusivity expiring in November 2017.

Last year, AstraZeneca agreed a licensing deal with generic firms Handa and Accord to enter a generic version of Seroquel XR in the US market on November 1st 2016, or earlier under certain circumstances.