Mazdutide phase 1b results from Innovent Biologics offer new hope for adolescent obesity in China

Why are phase 1b results for mazdutide a breakthrough in Chinese adolescent obesity treatment?

In a pivotal moment for obesity care in China, Innovent Biologics (HKEX: 01801) has announced positive phase 1b clinical results for mazdutide injection—a dual GLP-1 and glucagon receptor agonist—targeting Chinese adolescents living with obesity. The 12-week trial met its primary endpoint, delivering double-digit reductions in both body mass index (BMI) and absolute body weight for participants, far surpassing the placebo group. Notably, all patients completed the protocol, with no serious adverse events reported and no discontinuations due to safety issues, making safety a highlight alongside efficacy.

This development comes against the backdrop of a worsening obesity crisis in China. According to UNICEF, global obesity rates among children and adolescents aged 5–19 have surged from 3% to nearly 9.4% since 2000. The situation in China is even more pronounced, with obesity detection among those aged 7–18 skyrocketing from just 0.1% in 1985 to 9.6% by 2019, a staggering 75-fold increase. There are currently no approved weight-loss medications for children and adolescents in China, leaving a significant treatment gap that mazdutide aims to fill.

How was the Innovent Biologics phase 1b study on mazdutide designed, and what sets it apart from earlier obesity trials?

The multicenter, randomized, double-blind, placebo-controlled phase 1b trial recruited 36 Chinese adolescents aged 12 to under 18 with obesity, all of whom had previously failed to achieve a 5% BMI reduction despite at least three months of dietary and exercise intervention. Participants were randomized in equal proportions to receive either 4 mg or 6 mg of mazdutide, or placebo, for a total of 12 weeks.

Importantly, subjects met the criteria set by Chinese national standards for obesity screening, with an average baseline BMI of 34.12 kg/m² and a mean body weight of 95.83 kg. This high-risk profile and prior lack of response to lifestyle interventions underline the real-world relevance of the study’s outcomes.

What were the key efficacy and safety findings for mazdutide in this adolescent population?

Mazdutide’s weight loss efficacy was both statistically and clinically significant. Adolescents on 4 mg and 6 mg doses saw BMI reductions of 8.78% and 10.99%, respectively, and lost an average of 7.72 kg and 8.65 kg of body weight. By comparison, the placebo group recorded only a 1.73% BMI reduction and an average weight loss of 1.42 kg. All between-group differences achieved nominal p-values below 0.01, reinforcing the robustness of these findings.

Beyond the headline numbers, the trial showed a dose-dependent trend favoring the higher 6 mg dose. Additionally, mazdutide led to improvements across a spectrum of metabolic parameters—waist circumference, blood pressure, lipids, serum uric acid, liver transaminase levels, and glycemic control. This metabolic benefit aligns with the mechanism of action of dual GLP-1/glucagon receptor agonists, which are designed not only to promote weight loss but also to address broader cardiometabolic risk factors.

Safety outcomes were reassuring. No serious adverse events were observed, and the most common side effects were mild to moderate gastrointestinal reactions. All subjects completed the full course, pointing to a favorable tolerability profile. The pharmacokinetic profile mirrored that seen in adults, supporting the appropriateness of the selected dosing strategy.

What is the clinical and regulatory context for weight-loss drugs among Chinese adolescents?

The results spotlight an urgent clinical need: China currently lacks any approved pharmacological interventions for obesity in the pediatric and adolescent population. Obesity in youth carries profound long-term risks, from hypertension and dyslipidemia to early-onset type 2 diabetes and psychological distress. As lifestyle interventions alone frequently fail, particularly for those with severe obesity or entrenched metabolic syndrome, the arrival of an effective pharmacotherapy could be transformative.

Innovent Biologics’ results therefore represent more than just a single study win—they offer a potential pathway to the first approved adolescent weight-loss drug in China. Given the scale of the problem, with nearly a quarter of Chinese children and adolescents now overweight or obese, the addressable market is vast and socially urgent.

How do these results compare with previous adult obesity and metabolic disorder trials of mazdutide?

Mazdutide has already proven its mettle in adult populations. The drug is currently the subject of seven phase 3 clinical studies, five of which have met their primary endpoints. These include trials in adults with overweight or obesity, adults with moderate to severe obesity, drug-naïve adults with type 2 diabetes, and head-to-head studies versus dulaglutide and semaglutide. The drug’s efficacy in reducing body weight and improving glucose metabolism has been consistently robust across these studies.

Regulatory progress has kept pace. Mazdutide has been approved by China’s National Medical Products Administration (NMPA) for two indications: chronic weight management in adults (BMI ≥ 28 kg/m², or BMI ≥ 24 kg/m² with at least one comorbidity) and for glycemic control in adults with type 2 diabetes, both as monotherapy and in combination with other antidiabetic drugs.

What do leading experts say about the significance of these trial results for adolescent obesity care in China?

According to Professor Ni Xin and Professor Gong Chunxiu, both of Beijing Children’s Hospital at Capital Medical University, the phase 1b findings validate mazdutide as a breakthrough therapy for adolescent obesity in China. They pointed to the challenges of reversing obesity through lifestyle change alone and the importance of addressing the full spectrum of metabolic complications, not just weight loss. Both believe the data reveal the fundamental advantage of dual GLP-1/glucagon receptor agonism in delivering broad metabolic benefits and halting progression to adult metabolic syndrome.

Dr. Lei Qian, Chief R&D Officer of General Biomedicine at Innovent Biologics, emphasized that mazdutide’s results in adolescents mirror its performance in adults, noting similar pharmacokinetics and robust weight-loss efficacy. Dr. Qian stressed that the evidence lays a strong foundation for expanding mazdutide’s indications and for accelerating its clinical development in other at-risk populations.

What is the future roadmap for Innovent Biologics and mazdutide in obesity therapeutics?

On the strength of these results, Innovent Biologics has announced its intention to launch a phase 3 registration trial in Chinese adolescents with obesity or overweight in the near future. With no current competitors in the space, the biopharmaceutical firm is well positioned to claim a first-mover advantage in the world’s largest pediatric obesity market.

Mazdutide’s ongoing development program is ambitious. Beyond adolescent obesity, active and planned studies cover conditions ranging from metabolic dysfunction-associated steatohepatitis (MASH) and heart failure with preserved ejection fraction (HFpEF) to head-to-head comparison with tirzepatide in moderate-to-severe obesity. The drug’s broad metabolic effects—lowering blood pressure, lipids, uric acid, liver enzymes, and improving insulin sensitivity—suggest future utility beyond just weight management.

How are investors and the biopharma industry reacting to these results and Innovent Biologics’ strategy?

Although Innovent Biologics shares (HKEX: 01801) did not see immediate sharp movement following the release, the stock has shown resilience in the face of broader market volatility. Analysts following the sector suggest that market participants are closely watching the company’s next regulatory and clinical milestones, particularly as phase 3 trial planning accelerates. With successful adult approvals already on the books, the market’s expectation is for Innovent Biologics to build on its strong momentum and potentially shape the future landscape of pediatric obesity care in China.

Key takeaways: what the Innovent Biologics mazdutide phase 1b results mean for adolescent obesity in China

• Innovent Biologics reported positive phase 1b results for mazdutide in Chinese adolescents with obesity, showing double-digit reductions in both BMI and body weight over 12 weeks.

• The 4 mg and 6 mg mazdutide arms achieved 8.78% and 10.99% reductions in BMI, with corresponding average weight losses of 7.72 kg and 8.65 kg, significantly outperforming placebo.

• All participants completed the trial with no serious adverse events or discontinuations; most side effects were mild to moderate gastrointestinal reactions.

• This is the first major pharmacological obesity intervention in a Chinese adolescent population, addressing a large unmet clinical need as no approved weight-loss drugs currently exist for youth in China.

• The study also recorded metabolic improvements in waist circumference, blood pressure, lipid profile, liver enzymes, uric acid, and glycemic control, indicating potential benefits beyond weight loss.

• The pharmacokinetic profile in adolescents was similar to adults, supporting dose selection and translational value of prior adult studies.

• Innovent Biologics plans to launch a phase 3 registration trial in Chinese adolescents with obesity, aiming to secure first-mover status in this market.

• Mazdutide is already approved for adult chronic weight management and type 2 diabetes in China, and has met primary endpoints in five out of seven phase 3 trials in adults.

• Leading clinical investigators described the results as a breakthrough, highlighting mazdutide’s dual-action mechanism as especially promising for broader metabolic health.

• Institutional sentiment is cautiously optimistic, with investors and analysts watching for phase 3 progress and future regulatory filings as obesity rates in Chinese youth continue to climb.