AstraZeneca has announced that the US Food and Drug Administration (FDA) approved once-daily Seroquel XR (quetiapine fumarate) extended-release tablets for maintenance treatment of schizophrenia in adult patients. FDA has approved Seroquel XR for the acute treatment of schizophrenia in adult patients.

Schizophrenia patients experience high rates of symptom relapse, and as a result, there is an important need for options for long-term treatment of schizophrenia to help reduce the risk of the recurrence of acute psychotic episodes.

In the clinical trial supporting this approval, patients with schizophrenia who were treated with Seroquel XR experienced a significantly longer time to relapse, compared with patients receiving placebo. Patients receiving Seroquel XR demonstrated an 84 per cent reduction in the relative risk of relapse. Results showed the estimated risk of relapse after six months was 14.3 per cent in the Seroquel XR group versus 68.2 per cent in the placebo group. Differences in relapse rate between active treatment and placebo were large enough to require the study to be stopped early. The complete results of the clinical trial appear in the November 2007 issue of the journal Psychiatry 2007.

Schizophrenia is a serious brain disorder with symptoms including distorted perceptions of reality, hallucinations and delusions, illogical thinking, and flat or blunted emotions, affecting over 2 million American adults about one per cent of the population aged 18 and older.

The FDA approval for maintenance treatment of schizophrenia was based on clinical trial results in which patients who had responded to Seroquel XR for the treatment of schizophrenia for 16 weeks either continued on Seroquel XR or were switched to placebo. The primary endpoint was the time from randomisation to psychiatric relapse .

The adverse reactions reported for Seroquel XR were generally consistent with those reported in the short-term placebo-controlled schizophrenia trials. The most common treatment emergent adverse events for the Seroquel XR group versus placebo group in the randomised phase were insomnia (8.5 per cent vs. 17.5 per cent) and headache (7.4 per cent vs. 4.9 per cent)