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.

Treatment of Menopausal Vasomotor Symptoms With Fezolinetant, a Neurokinin 3 Receptor Antagonist: A Phase 2a Trial.

CONTEXT: The thermoregulatory center in the hypothalamus is stimulated by neurokinin 3 receptor (NK3R) activation and inhibited by estrogen-negative feedback. This balance is disrupted in menopause, producing vasomotor symptoms (VMSs). OBJECTIVE: To evaluate safety and efficacy of the NK3R antagonist fezolinetant in menopausal VMSs. DESIGN: Twelve-week, double-blind, randomized, placebo-controlled study. SETTING: Eight Belgian centers from September 2015 to October 2016. PARTICIPANTS: Generally healthy menopausal women aged 40 to 65 years with moderate/severe VMSs. INTERVENTIONS: Subjects were randomized (1:1) to 90 mg of fezolinetant twice daily or placebo for 12 weeks. MAIN OUTCOME MEASURES: Subjects captured VMS severity and frequency using an electronic diary. The primary outcome was change from baseline to week 12 in total VMS score with fezolinetant vs placebo. Secondary outcomes included timing of changes in frequency and severity of moderate/severe VMSs and quality-of-life assessments at weeks 4, 8, and 12. Pharmacodynamic and pharmacokinetic effects were assessed, as were safety and tolerability. RESULTS: Of 122 subjects screened, 87 were randomized and 80 (92%) completed the study. At week 12, fezolinetant significantly reduced total VMS score vs placebo (-26.5 vs -12.2, P < 0.001) and decreased mean frequency of moderate/severe VMSs by five episodes per day vs placebo. Severity and frequency of moderate/severe VMSs were reduced from the first day of treatment. Improvements were achieved in all quality-of-life measures. Fezolinetant was well tolerated. The most common fezolinetant-related adverse event was gastrointestinal disorder (n = 6). CONCLUSIONS: Fezolinetant rapidly and significantly reduced moderate/severe VMSs, supporting its potential as an effective nonhormonal treatment option for menopausal women.

The NK3 Receptor Antagonist ESN364 Suppresses Sex Hormones in Men and Women.

CONTEXT: Women's health disorders are commonly treated by agents that suppress the hypothalamic-pituitary-gonadal axis. NK3 receptor antagonism modulates this axis with distinct pharmacology compared to existing therapies. OBJECTIVE: The study aim was to evaluate safety, pharmacokinetics, and pharmacodynamics on gonadotropins and sex hormones after single- and multiple-dose administration of an NK3R antagonist to healthy men and women. DESIGN AND SETTING: This was a first-in-human, double-blind, placebo-controlled, combined single and multiple ascending dose trial. PARTICIPANTS: Forty-one men and 24 regularly cycling women participated in the study. INTERVENTION(S): In part 1 of the study, men received single oral doses of 3-180 mg or placebo. In part 2, men received placebo or 20, 60, or 180 mg each day for 10 days. In part 3, women received placebo or 20, 60, or 180 mg each day for 21 days, where dosing was initiated on day 3 ± 2 after menses. MAIN OUTCOME MEASURE(S): Safety, tolerability, pharmacokinetics, and pharmacodynamics on circulating levels of LH, FSH, testosterone, estradiol, and progesterone, in addition to physiological biomarkers of endometrial thickening, follicle growth, and the duration of the menstrual cycle were evaluated. RESULTS: ESN364 was well-tolerated and rapidly bioavailable with linear pharmacokinetics and no drug accumulation with repeated, daily oral administration. Drug treatment dose-dependently decreased basal LH, but not FSH, and consequently decreased estradiol and progesterone (in women) as well as testosterone (in men). The hormonal changes in women corresponded to delayed ovulation, decreased endometrial thickening, impeded follicular maturation, and prolongation of the menstrual cycle. Drug effects were rapidly reversible. CONCLUSIONS: Oral administration of the NK3R antagonist, ESN364, suppressed the hypothalamic-pituitary-gonadal axis in healthy volunteers by selective modulation of gonadotropin secretion, leading to a restrained decrease in ovarian hormone levels in women. These results suggest that ESN364 may offer therapeutic benefit in the treatment of women's health disorders with a mitigated risk of menopausal-like adverse events.