Kailera and Hengrui's ribupatide shows up to 20.2% weight loss and improved menstrual regularity in Phase 2 PMOS study
A mid-stage trial in China found the experimental weekly shot ribupatide cut weight by up to 20.2% and made periods more regular in women with PMOS, a condition formerly called PCOS.
Kailera Therapeutics and Jiangsu Hengrui Pharmaceuticals reported that their experimental weekly injection ribupatide, a GLP-1/GIP dual receptor agonist, helped women with polyendocrine metabolic ovarian syndrome (PMOS) lose up to 20.2% of their body weight in a Phase 2 trial, while also increasing how often they had menstrual cycles [1].
The results were presented at the European Association for the Study of Diabetes annual meeting in Milan [1]. Analysts at Leerink Partners called the Phase 2 performance "compelling, with supportive menstrual effects," adding that "these findings provide early support for activity beyond weight loss" [1].
What the trial measured
The study was run in China and enrolled 158 women ages 18 to 40 who had been diagnosed with PMOS and who had obesity or overweight [1]. Participants were randomly assigned to 1 mg, 2 mg or 4 mg of ribupatide, or to placebo. The main goal was weight loss at 32 weeks [1].
Weight loss rose with dose: about 10% at 1 mg, 15.1% at 2 mg and 20.2% at 4 mg, compared with 2.6% in the placebo group, according to the conference abstract [1]. All three doses beat placebo by a statistically significant margin [1]. Kailera's August 2026 business update described the same trial as showing mean weight loss of up to 21.2% using a different statistical approach called an efficacy estimand, with no plateau at week 32 [2]. The two figures come from different analyses of the same study, so they are not directly comparable.
On the menstrual measure, all three ribupatide groups saw cycles become more frequent, while cycles in the placebo group became less frequent [1]. In the 4 mg group, the mean number of cycles participants reported rose by 0.9 during the final 12 weeks of treatment [2]. Women with PMOS often have irregular periods and miss cycles [1].
On safety, there were no serious adverse events and no adverse events that caused participants to drop out of the study [1]. Kailera previously said most treatment-emergent adverse events in the trial were mild and gastrointestinal, in line with other GLP-1-based drugs [2].
Why it matters for patients
PMOS, the hormonal disorder formerly called polycystic ovary syndrome, is driven by dysregulated ovarian and neuroendocrine hormones and by insulin [1]. No GLP-1 drug is approved for it. Novo Nordisk's Wegovy (semaglutide) and Eli Lilly's Zepbound (tirzepatide) are not indicated for PMOS [1].
Even so, use is climbing. A Truveta analysis cited in a December 2025 Reuters report found that 17.6% of women with PMOS were on semaglutide or tirzepatide in 2025, up from 2.4% in 2021, though the firm noted the growth may partly reflect the broader spread of GLP-1 drugs rather than PMOS-specific prescribing [1].
Few companies are running drug programs aimed specifically at the condition. One is PostEra, whose molecule PERA-5720 is still in preclinical work ahead of a filing that would allow human testing [1].
Several caveats apply. This was a mid-stage trial of 158 women conducted entirely in China, not a late-stage study, and it is too small and too short to show whether the menstrual changes translate into fertility or long-term hormonal benefits. Whether ribupatide will ever be tested in a registration trial for PMOS in the United States has not been disclosed.
What happens next
Ribupatide's main development path is obesity. Kailera's global Phase 3 KaiNETIC program includes three placebo-controlled trials enrolling more than 4,700 participants, testing once-weekly doses up to 10 mg over 76 weeks in adults with obesity or overweight, with data expected in 2028 [2].
A US Phase 2b high-dose trial enrolled 264 participants with a BMI of 35 or greater and no type 2 diabetes, testing 10 mg, 13 mg, 16 mg and 20 mg over 48 weeks, with data anticipated in mid-2027 [2]. An oral version of ribupatide has an active investigational new drug application with the FDA, and global Phase 3 obesity trials are planned for the first half of 2027 [2].
Kailera launched in October 2024 with $400 million, built around assets licensed from Hengrui, and holds global rights outside Greater China [1].
Sources
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