As AstraZeneca posted a healthy set of financials for the third quarter, the company also revealed that it has reached an agreement in principle with authorities in the USA to resolve investigations into off-label marketing of the antipsychotic Seroquel.

The US Attorney’s Office in Philadelphia has been directing an investigation relating to Seroquel (quetiapine) involving a review of sales and marketing practices. These include allegations that AstraZeneca promoted the drug for non-indicated uses, and a second probe related to “selected physicians who participated in clinical trials involving Seroquel”.

The Anglo-Swedish drugmaker has now announced that a deal was agreed last month to settle the investigations, “subject to the negotiation and finalisation of appropriate implementing agreements”. It has set aside $520 million, which forms part of a $538 million provision.

As of October 9, AstraZeneca was defending 14,444 lawsuits and to date, over 2,600 additional cases have been dismissed by order or agreement and 1,635 with prejudice. The first two trials are now scheduled to begin in Delaware and New Jersey state courts in mid-January 2010.

AstraZeneca added that it is aware of 142 other cases that have been filed but not yet served and “has not determined how many additional cases, if any, may have been filed”. It said that some of the cases also include claims against other pharmaceutical firms such as Eli Lilly, Janssen Pharmaceutica, and/or Bristol-Myers Squibb, adding that it will “defend against the cases vigorously.”

AstraZeneca went on to note that by the end of the third quarter, legal defence costs of $623 million have been incurred in connection with Seroquel-related product liability claims.