Release Details

Results Demonstrate Latency to Persistent Sleep Was Significantly Improved In Subjects Receiving Indiplon Versus Placebo

SAN DIEGO, May 22 /PRNewswire-FirstCall/ -- Neurocrine Biosciences, Inc. (Nasdaq: NBIX) announced today that Neurocrine and Clinical Investigators from the Company's indiplon clinical development program presented an abstract reporting data from a Phase II clinical trial with indiplon at the upcoming American Psychiatric Association (APA) Meeting in San Francisco, May 17-22, 2003.

The abstract presented today, Thursday, May 22, 2003 explores the dose-related efficacy and tolerability of indiplon in healthy adults subjected to a well-accepted laboratory model of transient insomnia using objective polysomnography (PSG) assessments. This was a randomized, placebo-controlled, parallel group, dose-response Phase II clinical study with two doses of indiplon (15 mg. and 30 mg.) in 228 adult healthy subjects with no history of insomnia. The primary endpoint was Latency to Persistent Sleep (LPS) as measured objectively by PSG. Results demonstrated that LPS was significantly improved with those subjects receiving indiplon the mean time to LPS was 17.4 minutes (15 mg) and 16.2 minutes (30 mg.) compared to 34 minutes in the placebo group (p <0.001 for both comparisons). Safety evaluation and subjective measures of next day residual effect using the three validated measures of VAS, SCT and DSST confirmed that the drug was safe and well tolerated with no evidence of next day residual effects.

The first abstract which was presented on Monday, May 19, 2003, described the effect of alcohol on the pharmacodynamics (PD) and pharmacokinetics (PK) of a single dose of indiplon (10 mg.) in a randomized, placebo-controlled, double blind, three-way crossover Phase I clinical study in ten healthy adult volunteers. See our press release dated May 19, 2003.

Neurocrine is conducting one of the most comprehensive clinical programs in insomnia to address the multiple needs of younger and older adult patients with insomnia such as sleep initiation, sleep maintenance, and long-term administration. Neurocrine has initiated and is completing all of its multiple Phase III safety and efficacy trials to support a New Drug Application (NDA) registration expected in early 2004 for indiplon for multiple indications associated with insomnia.

Indiplon is a unique non-benzodiazepine sedative hypnotic that acts on a specific site of the GABA-A receptor. It is through this mechanism that the currently marketed non-benzodiazepine therapeutics also produce their sleep-promoting effects. However, indiplon has been shown to be more potent than the currently marketed non-benzodiazepines at the specific subtype of receptors within the brain believed to be responsible for promoting sleep.

Insomnia is a prevalent neurological disorder in the United States, with more than one-half 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% of the adult population reports that they have experienced insomnia every night or almost every night within the past year. Despite this widespread prevalence, insomnia remains a disorder with high unmet medical needs, including the ability to maintain sleep throughout the night without next-day residual effects.

Neurocrine Biosciences, Inc. is a product-based biopharmaceutical company focused on neurological and endocrine diseases and disorders. Our product candidates address some of the largest pharmaceutical markets in the world including insomnia, anxiety, depression, diabetes, multiple sclerosis, irritable bowel syndrome, eating disorders, pain, autoimmunity and certain female and male health disorders. Neurocrine Biosciences, Inc. news releases are available through the Company's website via the Internet at http://www.neurocrine.com .

In addition to historical facts, this press release contains forward-looking statements that involve a number of risks and uncertainties. Among the factors that could cause actual results to differ materially from those indicated in the forward looking statements are risks and uncertainties associated with Neurocrine's indiplon development program and business and finances including, but not limited to, risk that indiplon will not successfully proceed through Phase III clinical trials or that Phase III clinical trials will not show that it is safe and effective in treating humans; determinations by regulatory and governmental authorities; our reliance on corporate collaborators for commercial manufacturing and marketing and sales activities; uncertainties relating to patent protection and intellectual property rights of third parties; impact of competitive products and technological changes; availability of capital and cost of capital; and other material risks. A more complete description of these risks can be found in the Company's Form 10K for December 31, 2002 and the Company's most recent report on Form 10Q. Neurocrine undertakes no obligation to update the statements contained in this press release after the date hereof.

SOURCE Neurocrine Biosciences, Inc.