ObsEva announced the completion of a Phase 1 single and multiple ascending dose study of OBE022, a potential first-in-class, once daily, oral and selective prostaglandin F2alpha, or PGF2alpha, receptor antagonist for the treatment of preterm labor in weeks 24 to 34 of pregnancy. ObsEva is developing OBE022 to safely control PGF2alpha–mediated inflammation, decreasing uterine contractions and preventing membrane ruptures and cervical changes, which are the key features of preterm labor resulting in preterm birth. The study evaluated the safety, tolerability and pharmacokinetics of OBE022 in healthy post-menopausal female volunteers after single doses of 10 to 1,300 mg and multiple doses between 100 and 1,000 mg/day over 7 consecutive days. Based on preliminary data from the single and multiple doses administered in the Phase 1 study, OBE022 was observed to be readily absorbed and converted into the active stable metabolite OBE002. Exposure to OBE002 increased with dose of OBE022 and reached clinically meaningful exposure levels within an hour after administration, which is an important feature for orally administered preterm labor treatments. Median OBE002 half-lives were observed to be between 7 and 15 hours, which ObsEva believes is an adequate half-life for OBE022 to have once or twice daily dosing. Single and multiple administrations of OBE022 were well tolerated at all doses. There were no serious adverse events and no clinically relevant changes in safety parameters.