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Quetiapine XR Shown to Improve Quality of Life of Patients With Generalised Anxiety: Presented at ADAA

By Mike Fillon

SAVANNAH, Ga -- March 10, 2008 -- The onset of action of quetiapine XR monotherapy (50 and 150 mg/day) for the treatment of generalised anxiety disorder (GAD) was observed as early as day 4, earlier than with the active comparator, paroxetine 20 mg.

In addition, quetiapine XR at both dosage levels as well as the paroxetine improved the health-related quality of life of patients with GAD.

Researchers presented their findings here on March 7 at the Anxiety Disorders Association of America (ADAA) 28th Annual Conference.

GAD is a highly prevalent, chronic disorder which has considerable comorbidity with other psychiatric disorders, including depression and physical illnesses. "Furthermore, GAD is associated with a substantial impairment in health-related quality of life," said lead researcher Guy Chouinard, MD, Professor of Psychiatry, McGill University, Montreal, Quebec, Canada. The lifetime prevalence of GAD in the United States and the European Union has been estimated to be 4% to 5% and 2.8%, respectively.

In the past, several pilot investigator-sponsored studies have demonstrated that quetiapine XR is effective as monotherapy for GAD and as an adjunct to selective serotonin-norepinephrine reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors.

Quetiapine XR and its major active metabolite, norquetiapine, have a combination of effects on several neuroreceptors, including moderate to high antagonist affinity for dopamine D2 and serotonin 5 HT2a receptors, and moderate affinity for 5HT1a receptors. Norquetiapine is also a potent inhibitor of the norepinephrine transporter.

Chouinard said the objective of this new study was to evaluate the efficacy and tolerability of once-daily extended-release quetiapine XR monotherapy in outpatients with moderate to severe GAD without comorbid major depressive disorder.

The 10-week, multicentre, double-blind, randomised, placebo-controlled, parallel-group, active-comparator study consisted of an 8-week active-treatment and a 2-week drug-discontinuation/tapering phase. The primary endpoint was Hamilton Rating Scale for anxiety (HAM-A) total score change from baseline to week 8. Secondary endpoints included HAM-A psychic and somatic cluster change from baseline to week 8. Adverse events (AEs) were recorded throughout the study, and the statistical analyses included a 2-sided analysis of covariance last observation carried forward.

A total of 873 patients were randomised to quetiapine XR 50 mg/day (n = 221), quetiapine XR 150 mg/day (n = 218), paroxetine 20 mg/day (n = 217), or placebo (n = 217).

Mean HAM-A total score decreased significantly from baseline to day 4 with both quetiapine XR doses (P < .05). At week 8, significant decreases were seen with quetiapine XR 50 mg/day (-13.95, P < .05) and 150 mg/day (-15.96, P < .001), and with paroxetine (-14.45, P < .01) versus placebo (-12.30).

Mean HAM-A psychic cluster score, with a mean of 14.40 at baseline, was significantly decreased at week 8 by quetiapine XR 50 mg/day (-7.42, P < .01) and 150 mg/day (-8.64, P < .001), and paroxetine (-7.70, P < .001) versus placebo (-6.27).

Mean HAM-A somatic cluster score decreased from the baseline mean of 12.58 with quetiapine XR 150 mg/day (-7.37, P < .001) versus placebo (-6.00), but not with quetiapine XR 50 mg/day (-6.54, P = .15) or paroxetine (-6.74, P = .05).

Serious AEs were low (<2%) in all groups.

In the randomised treatment phase, the percentages of patients who withdrew due to an AE were 11.8%, 15.6%, 7.9%, and 4.1%, respectively.

The most common AEs recorded during the entire 8 weeks by the subjects taking quetiapine XR 50 and 150 mg, respectively, were dry mouth (15.9%; 25.7%), somnolence (21.8%; 25.2%), fatigue (15.0%; 16.5%), dizziness (11.8%; 15.6%), and headache (16.4%; 12.4%). For placebo patients, the most common AE was headache (18.0%). For those taking paroxetine, the most common AEs were somnolence (11.2%), dizziness (13.5%), headache (17.2%), insomnia (9.3%), and nausea (20.5%).

Dr. Chouinard said that since the researchers found that psychic anxiety scores were significantly improved for quetiapine XR 50 mg and 150 mg by day 4 and week 8, and quetiapine XR 150 mg significantly improved somatic anxiety cluster scores by week 8, with minimal AEs, both dosages proved effective and well tolerated while improving symptoms of anxiety in patients with GAD.

Funding for this research was provided by AstraZeneca Pharmaceuticals.


[Presentation title: Extended Release Once-Daily Monotherapy of Quetiapine Fumarate (Quetiapine XR), Paroxetine and Placebo in Generalized Anxiety Disorder (GAD). Abstract 23]

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