Randomized Controlled Trial of Neurokinin 3 Receptor Antagonist Fezolinetant for Treatment of Polycystic Ovary Syndrome

Context: Polycystic ovary syndrome (PCOS), a highly prevalent endocrine disorder characterized by hyperandrogenism, is the leading cause of anovulatory infertility. Objective: This proof-of-concept study evaluated clinical efficacy and safety of the neurokinin 3 (NK3) receptor antagonist fezolinetant in PCOS. Methods: This was a phase 2a, randomized, double-blind, placebo-controlled, multicenter study (EudraCT 2014-004409-34).The study was conducted at 5 European clinical centers. Women with PCOS participated in the study. Interventions included fezolinetant 60 or 180 mg/day or placebo for 12 weeks. The primary efficacy end point was change in total testosterone. Gonadotropins, ovarian hormones, safety and tolerability were also assessed. Results: Seventy-three women were randomly assigned, and 64 participants completed the study. Adjusted mean (SE) changes in total testosterone from baseline to week 12 for fezolinetant 180 and 60 mg/day were -0.80 (0.13) and -0.39 (0.12) nmol/L vs -0.05 (0.10) nmol/L with placebo (P< .001 and P< .05, respectively). Adjusted mean (SE) changes from baseline in luteinizing hormone (LH) for fezolinetant 180 and 60 mg/d were -10.17 (1.28) and -8.21 (1.18) vs -3.16 (1.04) IU/L with placebo (P< .001 and P= .002); corresponding changes in follicle-stimulating hormone (FSH) were -1.46 (0.32) and -0.92 (0.30) vs -0.57 (0.26) IU/L (P= .03 and P= .38), underpinning a dose-dependent decrease in the LH-to-FSH ratio vs placebo (P< .001). Circulating levels of progesterone and estradiol did not change significantly vs placebo (P> .10). Fezolinetant was well tolerated. Conclusion: Fezolinetant had a sustained effect to suppress hyperandrogenism and reduce the LH-to-FSH ratio in women with PCOS.