New clinical data released in May 2025 show that the investigational drug mazdutide, a once-weekly injection, produced clinically meaningful weight loss in Chinese adults who are overweight or have obesity. The findings come from a Phase III study of the medication, which is being developed jointly by Eli Lilly and Innovent Biologics.
Mazdutide, also known by the developmental codes IBI362 and LY3305677, is a dual agonist, meaning it activates two biological targets: the GLP-1 receptor and the glucagon receptor. It is an analog of oxyntomodulin, a naturally occurring hormone that plays a role in appetite regulation and energy balance. The drug is currently being evaluated in multiple late-stage clinical trials to assess its safety and efficacy for weight management and related metabolic conditions.
The Phase III study, whose results were announced this month, focused on a population of Chinese adults with overweight or obesity. According to the data released, participants who received once-weekly injections of mazdutide experienced “clinically relevant reductions in body weight.” The term “clinically relevant” is a standard benchmark in medical research, indicating that the weight loss achieved was significant enough to potentially improve health outcomes, such as reducing the risk of obesity-related complications like type 2 diabetes or cardiovascular disease. The study did not specify the exact percentage of weight loss or the number of participants in its public summary, but the finding marks a key milestone in the drug’s development path.
The development of mazdutide places it within a competitive field of next-generation weight-loss therapies. GLP-1 receptor agonists, such as semaglutide, have already demonstrated substantial weight-loss effects and have become widely prescribed. By adding glucagon receptor activation, mazdutide aims to further enhance energy expenditure and fat burning, potentially offering a complementary mechanism to the appetite-suppressing effects of GLP-1 stimulation. Researchers have been exploring dual and triple agonists as a way to improve efficacy and tolerability in obesity treatment.
The collaboration between Eli Lilly, a major U.S.-based pharmaceutical company, and Innovent Biologics, a Chinese biopharmaceutical firm, reflects a growing trend of international partnerships in drug development. Innovent has been leading the clinical development and regulatory efforts for mazdutide in China, while Eli Lilly holds rights in other global markets. The Phase III program includes multiple studies designed to evaluate the drug’s effects on weight loss, glycemic control, and other metabolic parameters in diverse patient populations.
As of the date of this report, mazdutide remains an investigational drug and has not yet been approved for marketing in any country. The positive Phase III results in Chinese adults provide a foundation for regulatory submissions, but the drug must still undergo review by health authorities before it can be made available to patients. No announcement has been made regarding the timeline for filing for approval in China or elsewhere.
Looking ahead, the next key developments to watch include the completion of other ongoing Phase III studies, which will provide a fuller picture of mazdutide’s safety profile and efficacy across different populations. Additionally, regulatory decisions in China and other major markets will determine when—and if—this dual agonist therapy becomes available as a treatment option for obesity. With obesity rates rising globally, the outcome of these trials and subsequent reviews will be closely monitored by clinicians, patients, and investors alike.
