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Quetiapine May Improve Generalised Anxiety Symptoms After 1 Week: Presented at ADAA

By Mike Fillon

SAVANNAH, Ga -- March 10, 2008 -- Once-daily monotherapy with oral quetiapine XR at 50 or 150 mg/day was effective in improving symptoms of anxiety in patients with generalised anxiety disorder (GAD) after 8 weeks in a study presented here at the Anxiety Disorders Association of America (ADAA) 28th Annual Conference.

In addition, the onset of action of once-daily, oral quetiapine XR monotherapy at 50, 150, and 300 mg/day in these patients was seen as early as week 1 after starting treatment, said lead researcher, Arifula Khan, MD, Medical Director, Northwest Clinical Research Centre, Bellevue, Washington.

GAD is a chronic, prevalent disorder associated with marked functional impairment and reduced quality of life. 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, Dr. Khan said in a presentation on March 7.

Current treatments for GAD include benzodiazepines, buspirone, or antidepressants such as tricyclic antidepressants, selective serotonin and norepinephrine reuptake inhibitors, and serotonin-norepinephrine reuptake inhibitors.

Quetiapine 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.

The 10-week, multicentre, double-blind, placebo-controlled, parallel-group, phase 3 study included an 8-week active-treatment, randomised phase and a 2-week, post-treatment drug-discontinuation/tapering phase. Primary endpoint was a Hamilton Anxiety Rating Scale (HAM-A) total score change from baseline to week 8. Secondary endpoints included HAM-A response and remission rates at week 8.

There were 951 patients randomised at the beginning of the study: quetiapine XR 50 mg/day (n = 234); 150 mg/day (n = 241); 300 mg/day (n = 241); placebo (n = 235). In the randomised treatment phase, the percentages of patients who withdrew due to an adverse event in each treatment arm were 15.9%, 18.1%, 24.4%, and 6.4%, respectively.

The two most common reasons for withdrawal in each group during the randomised treatment phase were:
· Placebo: depression (3 patients), irritability, and dizziness (2 patients each)
· Quetiapine XR 50 mg/day: somnolence-related events (11 patients), sedation (8 patients)
· Quetiapine XR 150 mg/day: sedation (14 patients), somnolence-related adverse effects (11 patients)
· Quetiapine XR 300 mg/day: sedation (24 patients), somnolence-related adverse effects (10 patients)

The researchers found that HAM-A total score mean change from baseline (overall baseline mean 24.6) to week 8 was significantly greater for quetiapine XR 50 mg/day (-13.3, P = .001) and 150 mg/day (-13.5, P < .001), but not 300 mg/day (-11.7, P = .24) versus placebo (-11.9). Significant change from placebo (-5.9) in HAM-A total score was observed at week 1 for 50 mg/day (-7.5, P = .001), 150 mg/day (-8.2, P < .001), and 300 mg/day (-7.2, P < .01).

They also found that HAM-A response rates (week 8) were significantly higher for quetiapine XR 50 mg/day (60.3%, P < .05) and 150 mg/day (61.5%, P < .05), but not 300 mg/day (54.9%, P = .37) versus placebo (50.7%). HAM-A remission rates (week 8) were significantly higher for quetiapine XR 150 mg/day versus placebo (37.2% vs 27.6%, P < .05); 50 mg/day and 300 mg/day remission rates were 36.1% (P = .08) and 28.6% (P = .96), respectively. Most common adverse events were dry mouth, somnolence, sedation, and headache. Serious adverse effects were less than 2.5% in all groups.

"We found that all three dosage levels of quetiapine XR monotherapy were generally well tolerated," said Dr. Khan.

Funding for this study was provided by AstraZeneca Pharmaceuticals.


[Presentation title: Extended Release Quetiapine Fumarate (Quetiapine XR) Monotherapy in the Treatment of Patients With Generalized Anxiety Disorder (GAD). Abstract 22]

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