SR-16234, a Novel Selective Estrogen Receptor Modulator for Pain Symptoms with Endometriosis: An Open-label Clinical Trial

Abstract

Background SR-16234 is a selective estrogen receptor modulator (SERM) structurally different from approved SERM and has been reported to have estrogen receptor (ER) α antagonistic activity and strong affinity with a weak partial agonistic activity to ERβ receptor. SR- 16234 showed strong inhibitory effects on transplanted endometrial cysts in the endometriosis model of rat and mouse. In this clinical trial, efficacy and safety of SR- 16234 have been evaluated in endometriosis patients. Methods This trial was an open-label single arm clini- cal trial. Ten patients with dysmenorrhea and pelvic pain associated with endometriosis and adenomyosis were enrolled in this trial, and received 40 mg of SR-16234 once daily for 12 weeks. The primary endpoint was the visual analogue scale (VAS) of pelvic pain. The sec- ondary endpoints included dysmenorrhea score, pelvic pain score, objective observations (stiffness of Douglas’ pouch, limitation of uterine movement, size of ovarian chocolate cysts, thickness of endometrium, and serum CA125 concentration) and safety. Results After oral administration of SR-16234 40 mg for 12 weeks, there were statistically significant decreas- es in pelvic pain VAS, total pelvic pain score, total dys- menorrhea score, stiffness of Douglas’ pouch, limitation of uterine movement compared with the baseline values. Conclusion The present trial suggested that a selective estrogen receptor modulator could be used for treatment of pain associated with endometriosis for the first time.