In October of last year, Kailera Therapeutics unveiled a whopping $600 million series B financing raised to fund a phase 3 trial of its injected, dual-agonist obesity drug ribupatide.
Four months later, the Massachusetts biotech and its China partner Hengrui have released top-line results from a phase 2 trial of their oral version of ribupatide, which indicate that it has a “potentially game-changing clinical profile,” according to Kailera Chief Medical Officer Scott Wasserman, M.D.
The study, which included 166 patients in China, demonstrated a mean weight loss of up to 12.1% over 26 weeks. The trial’s efficacy figure assumes that participants adhered to protocol treatment and excludes data collected after premature discontinuation or use of other weight loss therapies from the analysis, the companies explained.
Based on this estimand, participants taking a 10-mg daily dose of oral ribupatide achieved a mean weight loss of 6.9%. Those on doses of 25 mg and 50 mg each achieved a mean weight loss of 12.1%. There was no observed plateau in weight reduction, and the figures compare to a 2.3% efficacy figure for those on placebo.
While cross-trial comparisons can be challenging, the mean weight loss figure in a study that paved the way for the recent approval of Novo Nordisk’s GLP-1 pill was 16.6%. Meanwhile, in a trial of Eli Lilly’s orforglipron, which the company expects will be approved in the second quarter of this year, the dual-agonist pill provided a 12.4% mean reduction in weight. A key difference between the trials, however, is that these were conducted over 64 and 72 weeks respectively, while Hengrui’s study lasted 26 weeks.
As for side effects, ribupatide rates of vomiting were 2.4% at 10 mg, 11.4% at 25 mg and 7.5% at 50 mg, while nausea was reported for 11.9% of patients in the 10-mg arm, 22.7% in the 25-mg group and 20% in the 50-mg arm. In the Novo study, 31% of participants reported vomiting, while Lilly’s trial showed vomiting at a rate between 14% and 32%, depending on the dosing.
“The Hengrui phase 2 clinical trial results mark an important milestone in the expansion of our ribupatide franchise,” Wasserman said in the release. “We believe oral ribupatide could help to address the diverse needs of people living with obesity or overweight and meet patients wherever they are in their treatment journey.”
Wasserman added that the company would initiate a phase 2 trial of oral ribupatide this year, while Hengrui’s chief of clinical development of its metabolic diseases unit, Zi Ye, said the company plans to advance the treatment this year to a phase 3 study in China.
Obesity drug specialist Kailera launched in October 2024 with a $400 million series A funding round. Its top candidate, which has allowed the company to secure much of its funding, is injected ribupatide, or KAI-9531. The treatment is touted by the company as having a long half-life, allowing it to have more consistent exposure during a weekly dosing period.
A phase 3 trial of KAI-9531 in China showed in July of last year that it provided a mean weight loss of 19.2% at its highest 6-mg dose after 36 weeks, compared to a 20.9% weight loss figure for Lilly’s injected obesity treatment Zepbound.