Results from Tulip PETAL Study of elagolix announced by Neurocrine Biosciences

Neurocrine Biosciences, Inc. (Nasdaq: NBIX) today announced top-line efficacy and safety results from the Tulip PETAL Study (703 Study), its fifth Phase 2 clinical trial using its proprietary, orally-active nonpeptide Gonadotropin-Releasing Hormone (GnRH) receptor antagonist, elagolix, in patients with endometriosis.

"The efficacy and safety data from the Tulip PETAL Study are consistent with what we have seen in our previous elagolix studies. Women recognize significant improvement in endometriosis symptoms across multiple time points using elagolix, coupled with an excellent safety profile," said Chris O'Brien, M.D., Chief Medical Officer at Neurocrine. "Although certain daily efficacy scales employed in this trial will not be used in subsequent trials, we have and will continue to obtain important information from this Phase 2 study. Given the placebo response in some of the secondary efficacy endpoints, we plan to perform extensive analyses to understand the differences between North American and Central Eastern European clinical trial sites and subjects, the impact of trial design differences and patient baseline characteristics, and continue our assessment of appropriate statistical methods as we plan for our pivotal trials."

Tulip PETAL Study Design and Baseline Characteristics

The Tulip PETAL study was conducted in six countries in the Eastern European region (Romania, Poland, Ukraine, Hungary, Russia and Bulgaria). The study randomized 174 patients with a laparoscopic diagnosis of endometriosis into four treatment arms: elagolix 150 mg once daily, elagolix 250 mg once daily, leuprorelin monthly depot (Prostap SR®), or placebo; in a double-blind, double-dummy design. After completion of the initial three months of treatment, placebo and leuprorelin depot recipients were re-randomized in a double-blind manner to one of the elagolix arms for an additional three months. The top-line results reflect the initial three-month portion of the study. Unlike the previous Lilac PETAL Study (702 Study), the Tulip PETAL Study did not include a single-blind placebo lead-in phase prior to the first three months of treatment. The study was designed to compare active treatments to placebo and was not powered for active treatment group comparisons.

The study population overall had less severe endometriosis compared to the Company's prior endometriosis clinical trials; the mean Composite Pelvic Signs and Symptoms Scale (CPSSS) score was 8.1 (0-15 scale). The mean baseline daily score for Dysmenorrhea was 1.3, while the daily Non-Menstrual Pelvic Pain mean score was 0.89; both measured on a 0-3 scale.