Neurocrine Biosciences, Inc., a product-based biopharmaceutical company, announced results from two Phase I studies demonstrating that indiplon modified release does not effect respiratory functioning in healthy subjects or those with mild-to-moderate chronic obstructive pulmonary disease (COPD). These results were presented at the 157th annual meeting of the American Psychiatric Association (APA) in New York City.

The first study presented was conducted in 12 healthy male volunteers in a double-blind crossover design with indiplon modified release 30 mg, codeine sulfate 60 mg (as a positive control), or placebo. Indiplon modified release demonstrated no statistically or clinically significant effects on respiratory function as compared with placebo in response to carbon dioxide (CO2) challenge, whereas following treatment with codeine sulfate 60 mg, respiratory suppression was observed in response to CO2 challenge at all post-dose time points. The 30 mg dose of indiplon modified release was safe and well tolerated.

The second study presented evaluated the potential respiratory depressant effects, safety and tolerability of a 20 mg dose of indiplon modified release in a double-blind two-way crossover study in 18 patients with mild-to-moderate COPD. Primary outcomes consisted of the measurements of arterial oxygen saturation and the respiratory disturbance index of the effects of sleep apnea on total sleep time. Sleep quality was assessed using a subjective sleep quality questionnaire. In patients with mild to moderate COPD, indiplon modified release 20 mg had no clinically significant effects on respiratory function. Sleep quality was subjectively rated as "very good" or "excellent" by 50 per cent of subjects on indiplon versus 17 per cent of subjects on placebo.

"Effects of a sedative on respiratory function are often a concern, particularly in treating patients with insomnia. Results from these two studies demonstrate that indiplon modified release was safe and well tolerated and was not associated with any relevant effects on respiratory function in patients with chronic obstructive pulmonary disease," said Dr. Steven Hull, lead author and medical director, somniTech Inc.

Indiplon is a novel GABA-A receptor potentiator with high selectivity for the specific subtype of GABA-A receptors within the brain believed to be responsible for promoting sleep. Two formulations of indiplon, immediate release and modified release, are being developed to address different types of sleep problems. Indiplon was licensed from DOV Pharmaceutical in 1998.

Insomnia is a prevalent condition in the United States, with 58 percent of the adult population reporting trouble sleeping a few nights per week or more, according to the National Sleep Foundation's (NSF) Sleep in America Poll 2002. Approximately 35 percent of the adult population reports that they have experienced insomnia every night or almost every night within the past year. Insomnia remains a disorder with high unmet medical needs, including prolonged awakenings during the night with difficulty falling back to sleep.