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ObsEva Recovers Full Worldwide Rights on Nolasiban

Ad hoc announcement pursuant to Art. 53 LR of the SIX Swiss Exchange

Geneva, Switzerland – July 13, 2023 – ObsEva SA (SIX: OBSN), a biopharmaceutical company developing novel therapies for women's health, today 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 reverted to ObsEva.

“With one third of the ART cycles worldwide, China is a key market in fertility, and recovering the Chinese rights of nolasiban is a significant opportunity for ObsEva to address the huge unmet medical need in IVF and its global commercial potential.” said Fabien de Ladonchamps, Chief Executive Officer. “So far, Nolasiban has shown meaningful efficacy results on ongoing pregnancy rates with no safety concerns, and we look forward to resuming its clinical development, as well as evaluating potential strategic partnerships with well-established candidates.”

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 (1), 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 accounted for more than 3.1 million cycles worldwide in 2018 (2).

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

About ObsEva

ObsEva is a biopharmaceutical company developing novel therapies to improve women’s reproductive health and pregnancy. ObsEva has established a development program focused on improving in vitro fertilization success rates. ObsEva is listed on the SIX Swiss Exchange where it is traded under the ticker symbol “OBSN”. For more information, please visit

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ObsEva SA
Chemin des Aulx 12,
1228 Plan-les-Ouates

+41 22 552 1550



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