Release Details

Indiplon Modified Release Formulation Demonstrates Statistically Significant Improvement in Sleep Initiation

SAN DIEGO, March 1 /PRNewswire-FirstCall/ -- Neurocrine Biosciences, Inc. (Nasdaq: NBIX) today announced positive results from its Phase III trial with the modified release formulation of indiplon, achieving highly statistically significant results in adults with transient insomnia. The study was a randomized, double-blind, placebo-controlled, parallel-group, multi-center sleep laboratory Phase III clinical trial. The primary objective of the study was to assess the efficacy of two dose levels of indiplon modified release (20 mg and 30 mg) relative to placebo on sleep initiation in 325 healthy adult subjects. The primary endpoint for the study was Latency to Persistent Sleep (LPS), or time to sleep onset, as measured objectively by polysomnography (PSG). Indiplon modified release demonstrated a statistically significant reduction in LPS at both dose levels (p<0.0001) as compared to placebo. Improvements over placebo were approximately 50% for both dose groups. Patient reported Latency to Sleep Onset (LSO), or the amount of time it took subjects to fall asleep, was also significantly reduced (p<0.0001) for both doses, with a greater than 50% improvement relative to placebo. Safety results demonstrated that indiplon modified release was well tolerated and the incidence of adverse events for the indiplon treatment groups was similar to those studies we have conducted previously in the same population. In addition, there were no serious adverse events in the study.

"We are excited about the clinical results for our first Phase III clinical trial with indiplon modified release in transient insomnia. These results demonstrate the versatility of the modified release formulation and will enhance the data set for the modified release formulation with this new data on sleep initiation," said Dr. Henry Pan, Executive Vice President and Chief Medical Officer for Neurocrine Biosciences.

Study Design

This Phase III study was conducted in 11 centers in North America using a sleep laboratory model of the first night effect in a new environment combined with a phase advance (advancing subjects' bedtime 2 hours earlier than their normal bedtime) for the purpose of inducing transient insomnia in normal healthy adult volunteers who otherwise have a normal sleep pattern.

About Indiplon

Indiplon is a unique non-benzodiazapine agent that acts on a specific site of the GABA-A receptor. Indiplon has been shown to bind selectively to the specific subtype of GABA-A receptors within the brain believed to be responsible for promoting sleep. There are two formulations of indiplon, immediate release and modified release are being studied in clinical trials to address different types of sleep problems.

About Neurocrine Biosciences

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 Phase III safety and efficacy trials to support a New Drug Application (NDA) for the two formula expected in the first half of 2004 for indiplon for multiple insomnia indications. The Phase III program alone will have data from approximately 5,000 patients with different types of insomnia. Indiplon was licensed from DOV Pharmaceutical in 1998.

Insomnia is a prevalent condition in the United States, with nearly 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 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.

Neurocrine Webcast at Lehman Brothers Conference

Neurocrine will present at the Lehman Brothers Seventh Annual Healthcare Conference at Loews Miami Beach Hotel on Thursday, March 4, 2004 at 2:00 PM Eastern Standard Time; 11:00 AM Pacific Standard Time. Gary Lyons, President and CEO of Neurocrine will highlight the Company's recent clinical data results. The presentation will be simultaneously webcast and can be accessed on the Company's website at http://www.neurocrine.com .

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, certain female and male disorders, anxiety, depression, diabetes, multiple sclerosis, irritable bowel syndrome, eating disorders, pain, and autoimmunity. 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 may contain 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 the Company's indiplon clinical development program and planned regulatory activities. Specifically, the risks and uncertainties the Company faces with respect to its indiplon program include, but are not limited to, risk that indiplon may not successfully proceed through Phase III clinical trials or Phase III clinical trials may fail to demonstrate that indiplon is safe and effective in treating humans; risk that the Company may not complete indiplon Phase III clinical trials on the Company's projected timelines for various reasons, including the possibility that patient recruitment may be slower than expected; risk that the clinical investigators and contract research organizations upon which the Company relies to conduct its clinical programs may not be diligent, careful or timely, and may make mistakes, in the conduct of the programs; risk relating to the Company's dependence on contract manufacturers for clinical drug supply and compliance with regulatory requirements for marketing approval; risk that the Company may not successfully co-ordinate the completion and submission of planned regulatory filings on the Company's projected timelines; risk that the Company may not receive regulatory approval for indiplon or approval may be delayed; risks associated with the Company's dependence on corporate collaborators for commercial manufacturing and marketing and sales activities; uncertainties relating to patent protection and intellectual property rights of third parties; risks and uncertainties relating to competitive products and technological changes that may limit demand for the Company's products; risk that the Company will be unable to raise additional funding required to complete development of all of its product candidates; and the other risks described in the Company's Form 10-K for the year ended December 31, 2002, the Company's most recent report on Form 10-Q and the Company's final prospectus supplement and accompanying prospectus relating to its recent offering. Neurocrine undertakes no obligation to update the statements contained in this press release after the date hereof.

     Investor Contacts:
     Elizabeth Foster or Claudia Jones of Neurocrine Biosciences
     (858) 658-7600

     Media Contact:
     Liz Frank of Cohn & Wolfe
     (212) 798-9734

SOURCE Neurocrine Biosciences, Inc.