The Swiss biopharmaceutical company ObsEva SA recently announced randomization of the first patient EDELWEISS, a Phase 2b clinical study of OBE2109 for the treatment of endometriosis. Endometriosis is a painful, debilitating condition that affects approximately 176 million women globally between the ages of 15 and 49 and is a leading cause of infertility. OBE2109 is orally administered gonadotropin-releasing hormone (GnRH) antagonist that has been tested in more than 150 Japanese patients with endometriosis with interesting results on reductions of endometriosis-associated pelvic pain, analgesic use and bleeding days.

EDELWEISS is a double-blind, placebo-controlled and dose-ranging study that will assess the efficacy and safety of the novel GnRH antagonist in patients with endometriosis and pelvic pain. The study will be conducted in North America (46 center) and Europe (15 centers), on more or less 330 endometriosis patients who will be treated daily for 24 weeks, with an option to receive OBE2109 for another 28 weeks and then a period of treatment-free 24 week.

Primary endpoint of the study: menstrual and non-menstrual pelvic pain.

About OBE2109 and GnRH

OBE2109 is a novel, orally administered GnRH receptor antagonist with a potentially best-in-class profile in late-stage clinical development for the treatment of pain associated with endometriosis and heavy menstrual bleeding associated with uterine fibroids. OBE2109 acts by binding to and blocking the GnRH receptor in the pituitary gland, ultimately reducing estrogen production by the ovaries. Through previously reported results from this class of drugs and sophisticated pharmacological modelling, it has been established that maintaining estradiol within a specific target range provides the optimal balance between reducing the pain symptoms associated with endometriosis while mitigating bone density loss associated with excessive estradiol suppression.6 In Phase 2a studies conducted in Japan, patients treated with OBE2109 were observed to have a reduction of endometriosis-associated pain, analgesic use and bleeding days. ObsEva licensed OBE2109 from Kissei in late 2015 and retains worldwide commercial rights, excluding Asia, for OBE2109.