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

Hengrui Pharma and Kailera Therapeutics have announced positive results from a Phase 3 trial of their experimental dual-acting obesity drug, HRS9531, conducted 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

The Phase 3 trial, which enrolled 567 adults with obesity or overweight individuals with at least one weight-related medical condition, showed impressive outcomes after 48 weeks of treatment:

• Participants treated with HRS9531 experienced an average weight loss of about 18%, approximately 16% more than those given a placebo.
• Nearly 90% of participants receiving HRS9531 lost at least 5% of their body weight.
• Over 44% of treated individuals achieved at least 20% weight loss.
• In a pre-specified analysis, patients on the highest tested dose (6 mg) lost up to 19.2% of their body weight.

The companies noted that the drug's effects had not plateaued by the end of the trial, suggesting potential for further improvement with extended treatment duration.

Safety Profile and Next Steps

While specific safety data were not disclosed, Hengrui and Kailera 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.

Following these positive outcomes, Hengrui plans to file an approval application in China. Meanwhile, Kailera, which holds rights to the drug outside of Greater China under the name KAI-9531, will initiate global studies involving higher doses and longer treatment durations.

Industry Context and Competition

The development of HRS9531 reflects a growing trend in the pharmaceutical industry, with increased focus on obesity treatments and collaborations between Western companies and Chinese drug developers. Since late 2023, eight drug companies, including major players like Merck & Co., Novo Nordisk, and Regeneron Pharmaceuticals, have sought obesity drug candidates from China.

HRS9531 belongs to a class of dual-acting drugs that target both GLP-1 and GIP gut hormones, similar to Eli Lilly's approved drug Zepbound. While the results are promising, HRS9531 has yet to be tested in the larger, longer global studies that supported Zepbound's U.S. approval. Zepbound demonstrated up to 21% weight loss after 72 weeks in late-stage trials involving over 3,000 participants.

As the obesity treatment landscape becomes increasingly competitive, with companies like Lilly and Novo Nordisk developing oral medicines and other advanced therapies, Kailera and Hengrui will need to demonstrate HRS9531's potential advantages to stand out in the market.