AstraZeneca has been boosted by the news that regulators in the Netherlands have given the green light to a sustained-release version of the company’s blockbuster antipsychotic Seroquel.

The company noted that the Netherlands’ Medicines Evaluation Board has approved Seroquel XR (quetiapine fumarate) extended-release tablets, which have the benefit of offering schizophrenia patients the convenience of once-daily dosing, rather than twice-daily for the currently marketed version. With the new treatment, AstraZeneca said that patients can achieve a dose within the recommended range as early as the second day of treatment and the MEB approval also includes relapse prevention in the long-term treatment of schizophrenia.

Seroquel XR was approved in the USA in May 2007 and the Anglo-Swedish drugmaker says that it will proceed with a mutual recognition procedure, seeking similar approvals across Europe. The drug is also being studied in bipolar disorder, major depressive disorder and generalised anxiety disorder.

The original formulation of the antipsychotic had sales of $1.9 billion, up 12%, for the first six months of 2007 and these new approvals should only serve to push that figure up. The US patent on Seroquel will expire in 2017 so AstraZeneca will be looking to switch the drug's existing patients to the once-daily formulation.