Roche’s Experimental Obesity Drug Shows Powerful Weight Loss in Phase II Trial

Roche has reported strong Phase II clinical results for its experimental obesity medicine CT-388, raising optimism about the future of weight-loss treatment. The Swiss pharmaceutical company shared topline data showing sustained and clinically meaningful weight reduction in people living with obesity. The findings position CT-388 as a potential new option in a rapidly evolving therapeutic area.

CT-388 is a once-weekly injectable therapy designed to target two key metabolic pathways. It acts as a dual GLP-1 and GIP receptor agonist, which helps regulate appetite and blood sugar levels. Roche tested the medicine in a global Phase II study that followed participants for 48 weeks. The trial compared multiple dose levels against placebo in adults with obesity or overweight.

Patients who received the highest dose of CT-388 achieved particularly striking results. Roche reported a placebo-adjusted average weight loss of 22.5 percent at 48 weeks. Importantly, participants did not reach a weight-loss plateau during the study. Many continued losing weight through the final weeks of treatment. This trend suggests the therapy may deliver sustained benefits over time.

The proportion of patients reaching clinically relevant milestones also stood out. Nearly all participants on the highest dose lost at least five percent of their body weight. A large majority achieved weight loss of ten percent or more. Almost half lost at least twenty percent of their starting weight. More than one in four participants reached a thirty percent weight reduction by the end of the study.

The treatment also helped many patients move out of the obesity range altogether. More than half of participants receiving the highest dose reached a body mass index below 30. That threshold marks the transition from obesity to overweight. Only a small fraction of patients in the placebo group achieved the same outcome. This shift highlights the potential real-world impact of the therapy.

CT-388 delivered benefits beyond weight loss alone. The trial included participants with pre-diabetes, a condition that often accompanies obesity. Among those patients, nearly three quarters achieved normal blood glucose levels after 48 weeks of treatment. By contrast, very few patients in the placebo group reached normal glucose control. These findings suggest CT-388 could support metabolic health as well as weight reduction.

Safety and tolerability played a key role in Roche’s assessment. The company reported that CT-388 was generally well tolerated across dose levels. Most side effects were mild or moderate and affected the gastrointestinal system. This pattern aligns with other medicines in the same class. Only a small percentage of participants discontinued treatment because of adverse events. Roche reported no unexpected safety concerns during the study.

Roche’s leadership expressed confidence in the programme’s progress. The company described the results as encouraging and clinically meaningful. Executives highlighted the consistency of weight loss and the favorable safety profile. They also noted the absence of a weight-loss plateau as a positive signal for long-term treatment potential.

Based on these findings, Roche plans to move CT-388 into late-stage development. The company intends to launch two Phase III trials focused on obesity. These studies will evaluate the therapy in a larger and more diverse patient population. Roche is also continuing to study CT-388 in people with overweight and type 2 diabetes, aiming to better understand its metabolic effects.

The announcement comes at a time when obesity rates continue to rise worldwide. Excess weight increases the risk of type 2 diabetes, heart disease, and other chronic conditions. While several new weight-loss medicines have reached the market, many patients still struggle with access, tolerability, or long-term effectiveness. Roche aims to address these gaps with a therapy that combines strong efficacy with manageable side effects.

CT-388 also reflects Roche’s broader strategy in cardiometabolic disease. The company has expanded its pipeline to include treatments that target obesity and related conditions. Roche sees obesity as a complex, chronic disease that requires long-term medical solutions. By investing in innovative mechanisms, the company hopes to improve outcomes for millions of patients.

If future trials confirm the Phase II results, CT-388 could become a significant addition to the obesity treatment landscape. The data suggest it may help patients achieve substantial and sustained weight loss. The improvements in blood sugar control further strengthen its clinical appeal. For now, Roche’s latest results mark an important step forward in the search for effective obesity therapies.

References

Roche. (2026, January 27). Roche announces positive Phase II results for its dual GLP-1/GIP receptor agonist CT-388 in people living with obesity. Roche. Retrieved from https://www.roche.com/investors/updates/inv-update-2026-01-27

RTTNews. (2026, January 27). Roche: Phase II trial of CT-388 achieves statistically significant placebo-adjusted weight loss. RTTNews. Retrieved from https://www.rttnews.com/3613575/roche-phase-ii-trial-of-ct-388-achieves-statistically-significant-placebo-adjusted-weight-loss.aspx

Reuters. (2026, January 27). Roche’s experimental obesity drug delivers positive Phase II results. Reuters. Retrieved from https://www.reuters.com/business/healthcare-pharmaceuticals/roche-announces-positive-phase-ii-results-dual-glp-1gip-receptor-2026-01-27/

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