SJX-653

SJX-653 is a novel, potent, and highly selective small molecule neurokinin 3 (NK3) receptor antagonist developed as a non-hormonal, once-daily oral therapy. Its mechanism of action involves antagonism of the NK3 receptor, which plays a central role in regulating gonadotropin-releasing hormone (GnRH) secretion and is implicated in the generation of vasomotor symptoms (VMS), such as hot flashes associated with menopause. By blocking NK3 receptors in the hypothalamus, SJX-653 reduces excessive neurokinin B signaling that occurs during menopause due to declining estrogen levels, thereby alleviating VMS. Clinical studies have demonstrated that SJX-653 produces dose-dependent reductions in luteinizing hormone (LH) and testosterone levels in men—serving as pharmacodynamic markers for central NK3 antagonism—and has shown favorable safety and tolerability profiles. The drug is currently being developed by Sojournix for moderate to severe vasomotor symptoms due to menopause.