ObsEva SA announced that it has recovered full worldwide rights on nolasiban, a novel, oral oxytocin receptor antagonist being developed to improve clinical pregnancy and live birth rates in women undergoing embryo transfer after in vitro fertilization ("IVF"), following the termination of its sub-licensing agreement with Yuyuan BioScience (Yuyuan). In January 2020, ObsEva granted to Yuyuan an exclusive sublicense to use, register, import, develop, market, promote, distribute, offer for sale, and commercialize nolasiban for use in humans in the People's Republic of China, including Hong Kong and Macau. The terms of the sub-licensing agreement provided ObsEva with rights to terminate the agreement with immediate effect subject to certain development milestones not being met by Yuyuan within certain deadlines.

Under these terms, on July 12, 2023, ObsEva decided to notify Yuyuan of its breach to comply with certain set milestones and the license rights on nolasiban previously granted to Yuyuan forthwith revert to ObsEva. In its previous clinical trials of nolasiban, involving more than 1'700 randomized patients, ObsEva was able to demonstrate an average 5.03% absolute (15% relative) increase versus placebo of the 10 weeks ongoing pregnancy rate after embryo transfer following IVF, with a favorable safety profile, an increase considered as clinically very significant by IVF specialists. Indeed, with success rates of IVF procedures that could be as low as 30%, nolasiban might have the potential to meaningfully improve success rates of assisted reproductive technologies ("ART"), which accounting for more than 3.1 million cycles worldwide in 2018.

Meta-analysis of IMPLANT 1, IMPLANT 2 and IMPLANT 4 data (2) ICMART Preliminary World Report 2018.