Release Details

       Neurocrine Also announces Pharmacokinetic Results for NBI-34060
                      Modified Release (MR) Formulation

SAN DIEGO, Dec. 14 /PRNewswire/ -- Neurocrine Biosciences, Inc. (Nasdaq: NBIX) today announced dose related positive efficacy results with all three doses of NBI-34060 Immediate Release (IR) relative to placebo in a Phase II study in the elderly population of primary (chronic) insomnia. This study was a randomized, multi-center, double-blind, placebo-controlled, four-way crossover dose-response study in 42 patients over 65 years of age (mean 70 years, range from 65 to 85 years) with primary (chronic) insomnia. The primary endpoint was Latency to Persistent Sleep (LPS) compared to placebo as measured objectively by polysomnography (PSG). Latency to Sleep Onset (LSO) as reported subjectively by the patient was also collected during the study. NBI-34060-IR demonstrated a statistically significant effect on LPS relative to placebo at all dose levels (p?0.001) with up to a 61% improvement in the primary endpoint of LPS. In addition, up to 86% of the treated patients responded by going to sleep within 30 minutes as compared to only 40% of patients on placebo. Subjective LSO was also improved significantly over placebo in a dose-response manner from 30% to 50% (p<0.004). Overall, NBI-34060-IR was found to be safe, well tolerated and without next day residual sedation for all dose groups after approximately 270 administered doses.

Secondary efficacy as measured objectively by PSG also demonstrated statistically significant improvements on Total Sleep Time (TST) and Sleep Efficiency (SE) for the two higher doses (p<0.03). Statistically significant difference in subjective TST was also demonstrated in a dose-response manner (p<0.04) for all doses with the highest dose group showing approximately one hour increase in TST. These data indicate that the NBI-34060-IR treated patients not only fell asleep more rapidly but also stayed asleep longer. There were no next day residual effects observed with NBI-34060-IR at any dose level relative to placebo using the accepted standardized sedation tests of Digital Symbol Substitution Test (DSST), Symbol Copy Test (SCT) and Visual Analogue Scale (VAS) of sleepiness.

The elderly (over 65 years old) have the highest incidence of insomnia and are known to be more sensitive than the adult population to the residual effects of sedation. However, the safety profile in these elderly patients with primary (chronic) insomnia is consistent with results seen in previous studies conducted with NBI-34060 and confirm that the compound is well tolerated with no relevant effects on next day residual sedation. These results also demonstrate safety and efficacy in elderly patients at doses equivalent to those used in the adult population.

"The results from this study definitively confirm three other Phase II studies completed with NBI-34060-IR in more than 600 subjects demonstrating that the drug is highly active in reducing the latency to persistent sleep (LPS), the primary endpoint accepted by the FDA, with no next day residual effects even when given in the middle of the night," said Henry Pan, M.D., Ph.D., Executive Vice President of Clinical Development and Chief Medical Officer for Neurocrine Biosciences. "What is also exciting is that the IR formulation significantly increases the duration of sleep and can reduce night time awakenings which is not consistently seen with other short acting sleep aids. This gives us great confidence for success as we expand our ongoing pivotal Phase III program for the IR formulation and also for sleep maintenance with our MR formulation which follows closely on its heals. The lack of side effects compared to placebo in the elderly is also very reassuring since it is a population which often uses these drugs. This excellent safety profile in the elderly is likely due to a lack of alteration in the pharmacokinetics as has been reported previously for NBI-34060. A deleterious change in pharmacokinetics in the elderly population is a problem often seen with some other sleep aids."

In addition, Neurocrine today announced results from a pharmacokinetic Phase I study evaluating NBI-34060-Modified Release (MR) formulation. The study was a placebo controlled, parallel design, nighttime, pharmacokinetic study, involving 36 subjects and was designed to confirm that the MR formulation would achieve sufficient night time blood levels of NBI-34060 necessary to achieve sleep maintenance without inducing next day residual effects. Results from the study showed rapid absorption with drug levels that remained above the targeted therapeutic plasma levels required for sleep maintenance, resulting in a statistically significant improvement in Total Sleep Time (TST). This was achieved with no residual next day side effects such as sedation or drowsiness as measured by DSST, VAS and SCT scores as compared to placebo.

"We believe the MR formulation will translate into clinical benefit in patients who have difficulty in both falling asleep and staying asleep throughout the night," said Bruce Campbell, Ph.D., Senior Vice President of Development for Neurocrine Biosciences. "We are on track with our extensive Phase III clinical plans for the IR and MR formulations of NBI-34060 to address the comprehensive symptoms of insomnia which will provide one product with two formulations for the total sleep solution. The Phase III program with NBI-34060-MR is scheduled to begin in early 2002 and will run in parallel with the Phase III program in the IR formulation currently underway."

NBI-34060 is a non-benzodiazepine 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, NBI-34060 is more potent than the currently marketed non- benzodiazepines, including Ambien(R) and Sonata(R), and is more selective for 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 about one-half of the adult population reporting trouble sleeping a few nights per week or more, according to the National Sleep Foundation (NSF). Approximately 29% of the adult population reports that they experience insomnia every night or almost every night. It is also estimated that the elderly comprise 15% of the total insomnia population. 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, malignant brain tumors and peripheral cancers, diabetes, multiple sclerosis, irritable bowel syndrome, eating disorders, pain, stroke, and certain female 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 NBI-34060 development program and business and finances including, but not limited to, risk that NBI-34060 will not successfully proceed through Phase III clinical trials or that in later stage clinical trials will not show that it is effective in treating humans; determinations by regulatory and governmental authorities; 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 the year ended December 31, 2000, as amended, the current form 10Q and its most recent registration statement, as filed with the Securities and Exchange Commission, each of which should be read before making any investment in Neurocrine common stock. Neurocrine undertakes no obligation to update the statements contained in this press release after the date hereof.

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SOURCE Neurocrine Biosciences, Inc.
Web site: http: //www.neurocrine.com
CONTACT: Elizabeth Foster or Paul Hawran, both of Neurocrine Biosciences, Inc., +1-858-658-7600