A couple of days before regulatory advisors in the USA looks at the benefits of giving Crestor to many more patients, AstraZeneca has suffered a legal setback in its bid to defend the patents on its blockbuster cholesterol drug.

A US District Court, in Delaware, has rejected a motion brought by the Anglo-Swedish drugmaker to dismiss claims of inequitable conduct made by generic firms who are seeking to invalidate a patent on Crestor (rosuvastatin). The companies making a challenge on the patent, which expires in 2016, are Teva Pharmaceutical Industries, Aurobindo Pharma, Apotex, Par Pharmaceutical, Novartis’ Sandoz unit, Mylan, Glenmark Pharmaceuticals and Sun Pharmaceutical Industries.

AstraZeneca is also taking action against Aurobindo, Apotex, Cobalt, Par, Sandoz, Mylan and Sun, but not Teva and Glenmark, since they sent notice letters to the drugs giant that they are challenging two patents, expiring in 2020 and 2021, not the 2016 one. Regarding the latter, a full trial is now expected to go ahead in February and AstraZeneca spokesman Neil McCrae told Reuters that the company remains confident it will prevail.

The decision in Delaware has not surprised industry observers and analysts at Morgan Stanley issued a research note saying that “resolution of inequitable conduct claims at summary judgment is a rare occurrence given the often-subtle issues surrounding intent”. They added that “we continue to anticipate AstraZeneca will prevail in defending its '314 patent at the February 2010 hearing”.

Meantime, the US Food and Drug Administration has posted briefing materials in advance of the December 15th Endocrinologic and Metabolic Drugs Advisory Committee meeting to discuss the supplemental New Drug Application filed by AstraZeneca for Crestor.

That sNDA is seeking to expand the label on the drug to include the prevention of cardiovascular events in people with normal cholesterol levels but who have elevated C-reactive protein levels. The application was based on results of the landmark Jupiter trial.