Elinzanetant (NT-814), a Neurokinin 1,3 Receptor Antagonist, Reduces Estradiol and Progesterone in Healthy Women.
The ideal therapy for endometriosis (EM) and uterine fibroids (UF) would suppress estrogenic drive to the endometrium and myometrium, whilst minimizing vasomotor symptoms and bone loss associated with current treatments. An integrated neurokinin-kisspeptin system involving Substance P and neurokinin B acting at the neurokinin (NK) receptors 1 and 3, respectively, modulates reproductive hormone secretion and represents a therapeutic target.To assess the effects of the novel NK1,3 antagonist elinzanetant on reproductive hormone levels in healthy women.Randomized, single-blinded, placebo-controlled study.Thirty-three women attended for 2 consecutive menstrual cycles. In each cycle blood samples were taken on days 3/4, 9/10, 15/16 and 21/22 to measure serum reproductive hormones. In cycle 2, women were randomized to receive once daily oral elinzanetant 40, 80, 120 mg or placebo (N=8 or 9 per group).Elinzanetant dose-dependently lowered serum luteinizing hormone, estradiol (120 mg median change across cycle: -141.4 pmol/L, P=0.038) and luteal phase progesterone (120 mg change from baseline on day 21/22: -19.400 nmol/L, P=0.046). Elinzanetant 120 mg prolonged the cycle length by median of 7.0 days (P=0.023). Elinzanetant reduced the proportion of women with a luteal phase serum progesterone concentration >30 nmol/L (a concentration consistent with ovulation) in a dose-related manner in cycle 2 (P=0.002). Treatment did not produce vasomotor symptoms.NK1,3 receptor antagonism with elinzanetant dose-dependently suppressed the reproductive axis in healthy women, with the 120 mg dose lowering estradiol to potentially ideal levels for UF and EM. As such, elinzanetant may represent a novel therapy to manipulate reproductive hormone levels in women with hormone driven disorders.
Authors: Steve Pawsey, Edouard Gregory Mills, Elizabeth Ballantyne, Kirsteen Donaldson, Mary Kerr, Mike Trower, Waljit Singh Dhillo