AstraZeneca has suffered a setback after an Australian court decided that patents on its blockbuster cholesterol drug Crestor are invalid.

The decision from the Federal Court of Australia, which found three patents protecting Crestor (rosuvastatin) to be invalid, followed a legal challenge by generic drugmaker Apotex, Watson and Ascent Pharma. One of them is a  formulation patent which was set to expire in 2020.

AstraZeneca expressed its disappointment at the court’s move, saying it "remains committed to defending its intellectual property protecting Crestor in Australia". The company added that it is "carefully reviewing this decision and evaluating all legal options at this time, which could include filing an appeal and seeking to maintain existing preliminary injunctions".

The Anglo-Swedish drugmaker noted that this is limited to Australia and has no impact on the validity of patents related to Crestor in other countries nor does it have any impact on AstraZeneca’s financial guidance for 2013. Sales of the drug in Australia last year were in the region of $350 million.

Commenting on the judgement, Savvas Neophytou, an analyst at Panmure Gordon, said that "this is not good news and Australia is likely to join Canada and Brazil in allowing generic copies of Crestor on the market". He added that given Crestor's importance to the group (expected to contribute about 23% to 2013 revenues and 30% of profits) "we believe this increases pressure on management to undertake some sort of M&A".