AstraZeneca says that a US court has lifted a temporary injunction against South Korea’s Hanmi Pharmaceutical Co which was preventing the launch of a drug seen as an alternative to the former's blockbuster Nexium.

The Hanmi drug is Esomezol (esomeprazole strontium) which was filed with the US Food and Drug Administration in October 2010 and the data filed included comparative bioequivalence testing against Nexium (esomeprazole magnesium). In August, Hanmi and partner Amneal Pharmaceuticals of the USA received tentative approval from the agency for Esomezol and hope to launch soon, prior to the expected entry of generic versions of Nexium in the USA in May next year.

In June, AstraZeneca entered into an agreement with Hanmi and Amneal to “streamline litigation issues” regarding Esomezol, whereby the latter two conceded the validity and enforceability of a couple of patents that protect Nexium. The Anglo-Swedish drugmaker then filed an appeal in July concerning an earlier judgement in December 2012.

AstraZeneca now says that its appeal of claim construction from the New Jersey court remains ongoing. The Anglo-Swedish drugmaker adds that if Hanmi were to launch Esomezol, depending on the outcome of the appeal, the Korean firm "would be at risk of owing AstraZeneca patent-infringement damages".  

AstraZeneca concluded by saying it understands that Hanmi’s product is not AB-rated (ie drugs deemed to have bioequivalence by the FDA) and is not automatically substitutable for Nexium._