The U.S. Food and Drug Administration (FDA) has approved the antidepressant Cymbalta(R) (duloxetine HCl) for the treatment of generalised anxiety disorder (GAD), Eli Lilly and Company (NYSE: LLY) and Boehringer Ingelheim announced today.
The approval is based on the results of three randomized, double-blind, placebo-controlled studies in which the safety and efficacy of duloxetine in the treatment of GAD was studied in more than 800 non-depressed adults. In all studies, duloxetine significantly improved core anxiety symptoms as measured by the Hamilton Anxiety Scale (HAMA), compared with placebo.(i,ii ,iii) In addition, duloxetine patients reported greater improvement in functional impairment associated with the illness, including improved ability to perform everyday activities at work, home, and in social situations.(iv,v)
Duloxetine, a member of a class of drugs commonly referred to as serotonin and norepinephrine reuptake inhibitors (SNRI),(vi) was approved by Mexico for the treatment of GAD in October 2006. Lilly and Boehringer Ingelheim, which partner in the development and commercialization of duloxetine for neuroscience indications in most countries outside the United States and Japan, are evaluating further submissions in other regions, including Europe.
More than 7 million Europeans may have generalised anxiety disorder.(vii,viii) Worldwide prevalence is not known. While anxiety is a symptom of many mental health disorders, including depression, GAD is more than simple anxiety. The essential feature of the disorder is excessive anxiety and worry about a number of events and activities (such as work or school performance), occurring for a majority of days for at least six months.(ix) Because GAD presents with a variety of symptoms, both anxious and physical, it can be difficult to diagnose(x) and may have a negative impact on a person’s quality of life(xi) and ability to work.(xii) Symptoms can include exaggerated worry or chronic anxiety and irritability, which can lead to poor concentration and procrastination, as well as physical symptoms such as muscle tension, fatigue and nausea. Episodes of generalised anxiety disorder may be brought on, or worsened by, stressful life events. The illness also tends to be chronic with periods of exacerbation and remission.
In a pooled analysis of the three clinical trials supporting the approval, on average, patients treated with duloxetine for generalised anxiety disorder experienced a 46 percent improvement in anxiety symptoms compared with 32 percent for those who took placebo, as measured by the Hamilton Anxiety Scale (p<=0.001).(xiii,xiv,xv) In addition, patients in these studies experienced a 46 percent improvement in function, as measured by the Sheehan Disability Scale, compared with 26 percent for those who took placebo (p<=0.001).(xvi,xvii) The most common side effects in these studies included nausea, fatigue, dry mouth, drowsiness, constipation, insomnia, decreased appetite, hyperhidrosis, decreased libido, vomiting, ejaculation delay and erectile dysfunction.