Pfizer Inc's novel medicine pregabalin was shown to work quickly and be effective in treating a broad range of symptoms in patients with generalized anxiety disorder (GAD), according to data presented at the annual meeting the American Psychiatric Association.

Data from a combination of five placebo-controlled studies-including Phase II and pivotal Phase III trials-suggest that pregabalin may offer broad and rapid efficacy for the acute treatment of GAD. Pregabalin was shown to be significantly effective in each individual study in providing relief of both psychic and somatic anxiety symptoms as early as the first week of treatment.

In one of the pivotal studies, the antidepressant venlafaxine was a comparator drug. In this study, pregabalin achieved significantly faster improvement than placebo of psychic and somatic symptoms within the first week. Venlafaxine did not show improvement by week one for either psychic or somatic symptoms. In another pivotal study using the cas a comparator drug, data once again showed that pregabalin achieved significantly faster relief of psychic and somatic symptoms than placebo as early as week one. Alprazolam demonstrated significant improvement of only psychic symptoms by week one.

"Psychic and somatic symptoms represent a significant burden of disease experienced by patients with GAD," said Dr. Stuart Montgomery, Professor of Psychiatry, Imperial College School of Medicine, University of London. "Pregabalin represents a new class of drug for the treatment of GAD that works quickly and appears to offer the strengths of both the benzodiazepines and the antidepressants by providing effective control of somatic symptoms, at least as fast as the benzodiazepines, and more rapid control of psychic symptoms than antidepressants."

GAD is a chronic condition characterized by excessive worry-considered a psychic symptom-and fatigue and muscle tension-referred to as somatic symptoms. GAD also is characterized by other symptoms such as poor sleep, difficulty concentrating and restlessness that can worsen during times of stress. Approximately five per cent of people are affected by GAD at some point in their lives, though it is estimated that only one-third seek treatment.

"When treating GAD, physicians frequently prescribe benzodiazepines to provide fast relief of anxiety during the first few weeks before the anti-anxiety effects of antidepressants take hold," said Dr. Mark Pollack, study investigator and Director of the Center for Anxiety and Traumatic Stress Related Disorders, at Massachusetts General Hospital and Associate Professor of Psychiatry, Harvard Medical School. "Pregabalin appears to work at least as quickly as benzodiazepines in treating anxiety, and with less risk for dependence. Pregabalin also appears to work significantly faster than antidepressants, which can take up to two or three weeks to begin working."

The five combined studies represent data from 1,282 patients who received either pregabalin or placebo. All treatment groups had similar baseline clinical and demographic characteristics. Psychic and somatic symptoms as well as speed of onset were assessed using the standard measurement tool, the Hamilton Rating Scale for Anxiety (HAM-A).

Dizziness and drowsiness were the most common adverse events reported by pregabalin-treated patients. However, the majority did not result in discontinuation and most cases were resolved during the trial.

Pregabalin has a novel mechanism of action for potential treatment of anxiety disorders. Developed by Pfizer, pregabalin has been studied in an extensive clinical program involving over 8,000 patients worldwide. Pfizer plans to submit a New Drug Application to the U.S. Food and Drug Administration this year for pregabalin in the treatment of GAD, neuropathic pain and as an add-on therapy for epilepsy.

Pfizer is committed to pioneering targeted, innovative therapies for psychiatric and neurological disorders. The company's knowledge and expertise in the areas of anxiety, depression, schizophrenia, Alzheimer's disease and epilepsy have helped bring effective treatments to market.

Psychiatric and neurologic disorders represent one of the highest research priorities at Pfizer. Of the company's total R&D investment of $5.2 billion, the largest of any healthcare research company in the world, more than $1 billion is allocated to the development of more effective neuroscience compounds.