ObsEva regains China rights to pregnancy drug after partner misses deadlines

ObsEva has resecured the China rights to its pregnancy drug after Yuyuan BioScience allegedly failed to hit pre-agreed milestones on time.

The early-stage drug, called nolasiban, is an oral oxytocin receptor antagonist being developed to improve clinical pregnancy and live birth rates in women undergoing in vitro fertilization. After ObsEva significantly shrunk its head count and pipeline last year, nolasiban is one of only two drugs still listed on the biotech’s portfolio.

Obseva granted Yuyuan an exclusive sublicense to develop and commercialize nolasiban in China in January 2020. The agreement gave ObsEva the rights to terminate the deal with immediate effect if Yuyuan didn’t meet “certain development milestones … within certain deadlines,” the Swiss company said in a release July 13.

“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,” the company explained.

Things had seemed to be on track as recently as October, when Yuyan secured approval from Chinese authorities for a phase 1 trial to evaluate nolasiban in healthy adult females. At the time, ObsEva said the China trial would “provide critical observations that will inform nolasiban’s future development in the U.S. and abroad.”

Ending the partnership means ObsEva loses out on any chance to receive the over $130 million in combined development and sales milestones set out in the original agreement.

The company had previously tested nolasiban in a phase 3 trial to see whether it increased the rate of clinical pregnancy 10 weeks after embryo transfer. This year, the biotech set out plans for a phase 1 multiple dose study in preparation for a phase 2 trial in early 2024.

ObsEva’s only other remaining asset is preterm labor treatment ebopiprant, for which Xoma is entitled to royalties and milestone payments. ObsEva had hoped that selling off the license for ebopiprant to Xoma in November would be enough to halt debt proceedings in court and perhaps prevent the Swiss biotech from dropping off the Nasdaq, but, by February, the company had to demolish its U.S. C-suite in order to claw back further savings.