Hengrui and Kailera's Dual-Acting Obesity Drug Shows Promise in Phase 3 Trial

Hengrui Pharma and biotechnology startup Kailera Therapeutics have announced positive results from a Phase 3 trial of their experimental obesity drug, HRS9531, in China. The once-weekly injection demonstrated significant weight loss efficacy, positioning the companies to seek approval in China and initiate global late-stage testing.

Trial Results and Drug Efficacy

HRS9531, a dual-acting drug targeting GLP-1 and GIP gut hormones, showed impressive results in the 48-week trial:

• Participants lost an average of 18% of their body weight
• Nearly 90% of treated individuals lost at least 5% of their body weight
• Over 44% achieved at least 20% weight loss
• The highest tested dose resulted in up to 19.2% body weight loss

The study enrolled 567 adults with obesity or overweight individuals with at least one weight-related medical condition. Participants were randomized to receive weekly injections of 2mg, 4mg, or 6mg of HRS9531, or a placebo.

Kailera CEO Ron Renaud stated that the drug has "best-in-class potential," noting that the weight loss effects had not plateaued by the end of the trial, suggesting potential for further improvement with extended treatment.

Safety Profile and Next Steps

While specific safety data were not disclosed, the companies reported that most treatment-emergent adverse events were mild to moderate and primarily gastrointestinal-related. Detailed results are expected to be presented at a future medical meeting.

Hengrui plans to file for approval in China based on these results. Meanwhile, Kailera will initiate global studies involving higher doses and longer treatment durations, advancing the drug outside of China under the name KAI-9531.

Industry Context and Competition

The obesity drug market has become increasingly competitive, with major players like Eli Lilly's Zepbound and Novo Nordisk's offerings already established. Lilly's Zepbound demonstrated up to 21% weight loss after 72 weeks in late-stage trials involving over 3,000 participants.

Kailera's entry into this space is part of a broader trend of pharmaceutical companies turning to China for innovative drug candidates. A recent report by Jefferies revealed that one-third of the drug industry's licensing deal spending in the first half of 2025 involved China-originated drugs, up from 21% in 2023 and 2024.