AstraZeneca says it filed patent infringement actions in the USA against seven drugmakers who are trying to get their generic versions of the blockbuster cholesterol lowerer Crestor approved for marketing.

The news comes a month after the Anglo-Swedish drugmaker was stung by Canadian generics firm Cobalt Pharmaceuticals’ challenge to the US patents on Crestor (rosuvastatin). In November, Cobalt submitted an Abbreviated New Drug Application to the US Food and Drug Administration for approval to market copycat versions of Crestor in 5, 10, 20 and 40mg strengths, adding that its ANDA contains a Paragraph IV certification, alleging that the claims of two patents, which expire in January 2016 and August 2020 “are not infringed, invalid or unenforceable” by its move.

At the time an AstraZeneca spokesman told PharmaTimes World News that such patent challenges were par for the course and the firm had full confidence in its intellectual property portfolio protecting Crestor. Since then, however, it has received similar challenges from another eight generic drug manufacturers.

The firms making those challenges are Teva Pharmaceutical Industries, Aurobindo Pharma, Apotex, Par Pharmaceutical, Novartis’ Sandoz unit, Mylan, Glenmark Pharmaceuticals and Sun Pharmaceutical Industries. AstraZeneca is 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.

The importance of Crestor to AstraZeneca cannot be doubted as it contributed $691 million to the firm’s coffers in the third quarter. Those revenues are vital as a number of key drugs come under genuine generic threat, such as the antiulcerant Nexium (omeprazole) and Seroquel (quetiapine) for schizophrenia.