Novo Nordisk and United Laboratories report 19.7% weight loss for UBT251 in Chinese phase 2 trial
An experimental triple-agonist injection produced 19.7% average weight loss at 24 weeks in a Chinese trial, but it is unapproved and its long-term effects are unknown.
Novo Nordisk and The United Laboratories International Holdings reported positive topline results from a phase 2 trial in China of UBT251, an experimental once-weekly injection for weight loss. People taking the highest dose tested, 6 mg, lost an average of 19.7 percent of their body weight — about 17.5 kg — at 24 weeks, compared with 2.0 percent, or about 1.6 kg, for placebo [1].
UBT251 is a synthetic peptide that activates three hormone receptors at once: GLP-1 and GIP, the targets of approved weight-loss drugs, plus glucagon [1][2]. The randomized, double-blind, placebo-controlled trial enrolled 205 people in China with obesity, defined as a BMI of at least 28.0, or with overweight, defined as a BMI of 24.0 up to 28.0, plus at least one weight-related health condition [1]. Participants' average starting weight was 92.2 kg and average starting BMI was 33.1 [1]. The trial tested once-weekly 2 mg, 4 mg and 6 mg doses against placebo, with the percentage change in body weight at 24 weeks as the primary measure [1].
The companies said UBT251 appeared safe and well tolerated. The most common side effects were gastrointestinal, and the vast majority were mild to moderate and eased over time, a pattern consistent with existing incretin-based therapies [1]. One of the two published reports of the results also lists improvements in lipids along with waist circumference, blood glucose and blood pressure; the other lists waist circumference, blood glucose and blood pressure [1][2]. Detailed data from the trial are expected to be presented at a medical congress later this year [1].
Under an agreement signed in March 2025, a United Laboratories unit, The United Bio-Technology (Hengqin) Co. Ltd., handles development in mainland China, Hong Kong, Macau and Taiwan, while Novo Nordisk handles the rest of the world [1]. "The success of the phase 2 clinical trial of UBT251 in China represents another significant milestone in TUL's innovation-driven development," said Tsoi Hoi Shan, chairman of United Laboratories [1].
Why it matters for patients
UBT251 is not approved by the FDA or any other regulator, so it is not an option today. One industry report projects a China phase 3 trial starting in the third quarter of 2026, a possible Chinese filing in 2028 and possible U.S. or European filings in 2029, but those are forward-looking estimates rather than company commitments, and the companies have not confirmed them [2].
The 24-week treatment period is short. Whether the weight loss continues beyond 24 weeks, and whether it is maintained after treatment stops, has not been reported [1][2]. One industry report notes that the 19.7 percent figure at 24 weeks is in the range of results seen with tirzepatide (Zepbound, Mounjaro) in a separate trial, which reported 20.9 percent at 72 weeks, but the trials differ in length, population and design, so no direct comparison can be drawn [2].
The phase 2 trial enrolled only Chinese adults who had obesity or overweight plus at least one related health condition [1]. Whether the results would carry over to a broader U.S. population has not been reported. The trial also did not measure whether the drug reduces heart attacks, strokes or deaths; improvements in blood pressure and blood glucose were reported, but whether those translate into fewer cardiovascular events is not yet known [1][2].
No information on price, insurance coverage or supply has been disclosed. Approved GLP-1 and dual-agonist drugs — semaglutide (Ozempic, Wegovy, Rybelsus) and tirzepatide (Mounjaro, Zepbound) — remain the products patients can currently be prescribed, and UBT251, if it reaches the market, would be an additional option rather than a replacement [2].
What happens next
The companies said they plan to start a phase 3 trial in Chinese patients with overweight or obesity based on these results [1]. United Biotechnology is scheduled to present detailed phase 2 data at a medical congress later this year [1]. Novo Nordisk expects to begin a phase 2 trial of UBT251 in people with type 2 diabetes in the second half of 2026 [1]. Novo recently started a global phase 1b/2a trial testing different doses for up to 28 weeks in about 330 people with overweight or obesity, with topline results expected in 2027 [1].
Sources
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