The U.S. Food and Drug Administration (FDA) approved in May AstraZeneca's
once-a-day formulation of its schizophrenia drug quetiapine (Seroquel) for the
treatment of schizophrenia in adult patients.
The once-daily version is called Seroquel XR (quetiapine fumarate)
extended-release tablets. It will become available during the latter half of
AstraZeneca said it developed Seroquel XR so that patients using Seroquel
for schizophrenia would have a more convenient dosing than is the case with
Seroquel, where a tablet has to be taken more than once a day.
FDA approval of Seroquel XR was based on a six-week, double-blind,
randomized, placebo-controlled study investigating efficacy and safety in 573
patients experiencing acute exacerbations of schizophrenia. Subjects getting
Seroquel XR received doses of 400 mg/day, 600 mg/day, or 800 mg/day.
Subjects were evaluated with the Positive and Negative Syndrome Scale
(PANSS) at the start and end of the six-week study. The total PANSS score
changes of the subjects receiving Seroquel SR were compared with the total
PANSS score changes of the subjects getting a placebo.
Subjects receiving Seroquel XR showed a significant improvement in PANSS
scores compared with subjects getting a placebo regardless of whether they
received a dose of 400 mg/day, 600 mg/day, or 800 mg/day.
In a second analysis, the efficacy of Seroquel XR was evaluated based on
changes in total PANSS scores over the six-week period, as well as on the
basis of changes in individual schizophrenia symptoms—positive symptoms,
negative symptoms, symptoms of general psychopathology, aggression, and
depression—over that period.
Compared with placebo, Seroquel XR at all three doses led to a significant
reduction in total PANSS scores, positive symptoms, symptoms of general
psychopathology, and aggression. Compared with placebo, Seroquel XR at 600
mg/day or at 800 mg/day led to a significant reduction in negative symptoms
Seroquel XR was generally well tolerated in the trial. The most commonly
observed adverse reactions were dry mouth, somnolence, dizziness, and
"Clinical trial data demonstrate that Seroquel XR is a safe and
effective treatment option for schizophrenia," Charles Schulz, M.D.,
chair of psychiatry at the University of Minnesota, said in a press release
issued by AstraZeneca.
According to the same press release, Seroquel XR is not approved for the
treatment of patients with dementia-related psychosis. Elderly patients with
dementia-related psychosis treated with second-generation antipsychotics such
as Seroquel have been found to be at an increased risk of death compared with
elderly patients taking a placebo.
Seroquel was included in the National Institute of Mental Healt h's CATIE
(Clinical Antipsychotic Trials of Intervention Effectiveness) study
(Psychiatric News, April 21, 2006). Seroquel has also been approved
by the FDA to treat both the depressive and acute manic phases of bipolar
disorder (Psychiatric News, December 1, 2006). ▪