AstraZeneca Plc won a U.S. court battle on Thursday over product liability claims for its blockbuster Seroquel schizophrenia treatment, the first such case to go to trial.

Thousands of plaintiffs have filed lawsuits claiming that Seroquel caused their diabetes and that the drugmaker failed to adequately warn patients.

AstraZeneca denies the allegations and said on Thursday that it believed all the patients still pursuing cases either already had diabetes or were at high risk of developing it before they started taking the Astra drug.

The drug firm said nine previous cases prepared for trial had been dismissed and some 2,600 more had been abandoned by the plaintiffs' lawyers.

Astra shares were up 0.85 percent at 1529 GMT in London.

In case after case, jurors, judges and even plaintiffs' lawyers themselves have found that plaintiffs simply cannot show through any accepted scientific method that AstraZeneca is responsible for their alleged injuries, the Anglo-Swedish drugmaker said in a statement.

In the cases that have been prepared for trial to date...the facts show that the plaintiffs either already had diabetes or had so many pre-existing risk factors that they were already at a significantly increased risk of diabetes before they first took Seroquel.

Seroquel was first approved in the United States 1997 and had sales of $4.9 billion in 2009.

It is currently approved for depressive episodes in bipolar disorder in adults, as well as some manic and bipolar disorders in children over 10 and schizophrenia and adults and children over 13.

The jury in New Jersey state court started deliberating on Wednesday after the roughly month-long trial, the company said.

(Editing by Antonia van de Velde)

Bipolar disorder