AstraZeneca blockbuster faces copycat threat

Seroquel, AstraZeneca's fastest-growing medicine, has come under attack from a copycat drug maker which wants to launch its own version, years earlier than the City expected competition.

A filing with the US Food & Drug Administration (FDA) raised the prospect that Teva Pharmaceutical is close to being able to launch its version of the schizophrenia drug, which accounts for 10 per cent of AstraZeneca's sales.

The UK giant - one of the world's top 10 pharmaceuticals companies - said it would vigorously defend its patents, which it believes protect Seroquel from competition until 2012.

Teva told AstraZeneca this week that it had filed an abbreviated new drug application (Anda) and was challenging a core patent behind Seroquel. Teva says it is invalid and its version does not infringe AstraZeneca's intellectual property. The UK company said it was evaluating Teva's notice, but analysts expect it to sue Teva.

Seroquel is making sales of more than £120m a month and growing at 35 per cent a year, with most profits generated in the US. Even if its legal challenge were to fail, it would have the effect of delaying approval of the Israeli company's version until 2008 at the earliest.

"The company continues to have full confidence in its intellectual property protecting Seroquel," AstraZeneca told shareholders yesterday. "The company has 45 days within which to commence a patent infringement lawsuit against the filer of an Anda that would automatically stay, or bar, the FDA from approving the Anda for 30 months."

Teva's move comes as the generics industry becomes ever more bold in challenging Big Pharma's blockbuster drugs at an early stage in their life cycle. The arrival of generic competition invariably causes a collapse in sales and profits of a branded medicine.

AstraZeneca shares slipped 29p to 2,639p yesterday to reflect the new risk to what analysts described as its most important drug. Seroquel has been its major success in a period when other hoped-for blockbusters - the lung cancer drug Iressa, the blood-thinner Exanta and the cholesterol-buster Crestor - have proved poor sellers or failed to win approval for launch.