A First in Human Study Consisting of a Two-Part, Double-Blind, Placebo-Controlled, Escalating Single and Multiple Dose Study of VA111913 TS in Adult Non-Pregnant Women Volunteers With a Single Dose, Open, Fed vs. Fasting Crossover Phase

VA111913 TS is a selective V1a-receptor antagonist. The hypothesised mechanism of action of a V1a receptor antagonist in dysmenorrhea has been described in literature. Contractions of the uterine muscle are required for normal menstruation. Women with dysmenorrhea have increased uterine myometrial tone and contractions and decreased blood flow to the uterus. These abnormalities have been shown to lead to the pain experienced in dysmenorrhea. Thus, if a drug is able to reduce the hyperreactivity of the uterus to physiological levels then the pain experienced in dysmenorrhea may be controlled. In humans, vasopressin, via the V1a receptor, is able to potently induce contractions in both uterine smooth muscle and uterine blood vessels. Thus, a V1a receptor antagonist will potentially inhibit these contractions and in turn reduce the pain experienced in dysmenorrhea.