Hengrui Pharma and Kailera Therapeutics, have announced positive topline results from the Phase 3 clinical trial (HRS9531-301) of HRS9531, a once-weekly injectable dual GLP-1/GIP receptor agonist for adults with obesity or overweight. The randomised, double-blind, placebo-controlled study was conducted in China and included 567 participants.
The trial met both its primary endpoints. Participants receiving HRS9531 (2 mg, 4 mg, and 6 mg) experienced greater average weight loss and a higher percentage achieved body weight reductions of at least 5 per cent compared to placebo after 48 weeks of treatment.
Under the primary analysis (treatment policy estimand), participants treated with HRS9531 achieved a mean weight loss of up to 17.7 per cent, with a placebo-adjusted difference of 16.3 per cent. Up to 88.0 per cent of participants experienced a minimum of 5 per cent weight loss, and 44.4 per cent saw reductions of at least 20 per cent. A supplementary analysis (hypothetical strategy estimand) indicated a mean weight loss of up to 19.2 per cent, with a 17.7 per cent placebo-adjusted difference.
The study demonstrated a safety and tolerability profile consistent with other GLP-1-based treatments. Most treatment-emergent adverse events (TEAEs) were gastrointestinal-related and mild to moderate in severity.
The Phase 3 findings follow results from a prior Phase 2 study (NCT06054698), in which participants on an 8 mg dose of HRS9531 achieved a mean weight loss of 22.8 per cent (21.1 per cent placebo-adjusted) after 36 weeks, with no plateau in weight loss. The supplementary analysis from that trial showed a mean weight loss of 23.6 per cent (21.7 per cent placebo-adjusted).
“We are delighted to share the data from this landmark study. This is a huge step forward in providing innovative solutions to meet the needs of people living with obesity,” said Hong Chen, Head of Metabolism Department I at Hengrui Pharma. “The positive data from the HRS9531-301 study demonstrated meaningful, sustained weight loss. With an affirmed safety and tolerability profile, we strongly believe in its potential to help more people living with obesity reach their individual weight loss goals. Based on these robust and encouraging clinical results, we are accelerating our efforts to advance this highly promising candidate. We look forward to filing for market approval in China as soon as possible to bring HRS9531 to patients struggling with obesity and overweight.”
“We commend our colleagues at Hengrui for these impressive Phase 3 clinical results, building on the strong momentum behind HRS9531 (KAI-9531). As Kailera prepares to advance KAI-9531 into a global clinical program, we look forward to evaluating both higher doses and longer duration of treatment to expand on KAI-9531’s best-in-class potential,” said Ron Renaud, President and Chief Executive Officer of Kailera. “Together with Hengrui, we believe KAI-9531 has tremendous potential to improve the lives of countless individuals worldwide, including those with higher BMIs who are seeking greater weight loss to achieve optimal health.”
Hengrui intends to present the full trial data from HRS9531-301 at an upcoming scientific conference.
About the HRS9531-301 Trial
The HRS9531-301 trial was conducted in China among adults aged 18 and above with a body mass index (BMI) ≥28 kg/m² (obesity) or ≥24 kg/m² (overweight) and at least one weight-related comorbidity. Participants did not have diabetes. The trial enrolled 567 individuals, of whom 531 completed the study. Participants were randomised in a 1:1:1:1 ratio to receive weekly subcutaneous injections of 2 mg, 4 mg, 6 mg of HRS9531 or placebo over a 48-week period.
About HRS9531 (KAI-9531)
HRS9531 is a dual GLP-1/GIP receptor agonist in development as an injectable peptide for type 2 diabetes, obesity and related metabolic conditions. To date, more than 2,000 participants have been dosed with HRS9531 across Phase 1, 2 and 3 studies in China. Kailera Therapeutics is advancing the compound globally (outside Greater China) under the name KAI-9531.