AstraZeneca has received some bad news in Canada after a court decided the company cannot stop a generic version of its antiulcerant blockbuster Nexium from hitting the market.

The Anglo-Swedish drugmaker has revealed that the Federal Court of Canada has dismissed its request to prohibit the country’s Minister of Health from issuing a notice of compliance (NOC) for regulatory applications for a copycat version of Nexium (esomeprazole) submitted by generics specialist Apotex. This means that versions of the drug, which had worldwide sales in the first quarter of $1.30 billion (+27%), could enter the market before the expiry of AstraZeneca's Canadian patents, the first of which expires in 2013 through to 2019.

AstraZeneca added that it is reviewing the ruling, which relates to only one of Nexium's Canadian patents, and evaluating its options, which could involve the filing of the lawsuit. The company added that in a Canadian proceeding seeking prohibition of an NOC, a presiding court does not rule on the validity of patents “and this decision has no bearing on cases in other jurisdictions”. The proceedings “are summary in nature and involve no discovery process or witness testimony in court”, it added.

Though a very big seller elsewhere, AstraZeneca notes that turnover of Nexium in Canada in 2009 reached $217 million. As such, “in the event of a near-term at-risk launch” of generic esomeprazole, the company does not expect to alter its 2010 core earnings per share guidance range of $6.05-$6.35.

Across the border in the USA, AstraZeneca fended off the threat of an imminent copycat version of Nexium at the beginning of this year by settling a patent dispute with Teva Pharmaceutical Industries, allowing the Israeli firm to enter the US market with its drug on May 27, 2014. A similar deal was struck with Ranbaxy Laboratories in April 2008. which was the first to file its generic version of Nexium with the US Food and Drug Administration, so it will have 180 days of marketing exclusivity.