Roche Reports Strong Phase II Results For Obesity Drug CT-388, GLP-1 Receptor Agonist Delivers Over 22% Weight Loss in Roche Phase II Trial

Roche reported positive topline findings from its Phase II CT388-103 study evaluating CT-388, a once-weekly injectable dual GLP-1/GIP receptor agonist for obesity. Participants receiving doses titrated up to 24 mg achieved a placebo-adjusted weight loss of 22.5% at 48 weeks under the efficacy estimand, with no evidence of a plateau and a clear dose-response effect. Under the treatment-regimen estimand, weight loss reached 18.3% versus placebo, meeting strong statistical significance.

At the highest dose, the majority of treated patients experienced substantial reductions in body weight: nearly 96% lost at least 5%, 87% lost 10% or more, close to half lost 20% or more, and about one quarter achieved reductions of 30% or greater. Among participants who entered the trial with pre-diabetes, 73% normalized blood glucose levels after 48 weeks of treatment compared with just 7.5% in the placebo group.

“We are pleased to see such meaningful weight loss in people treated with CT-388,” said Levi Garraway, M.D., Ph.D., Roche’s Chief Medical Officer and Head of Global Product Development. “The robust weight loss combined with a well-tolerated safety profile reinforces our confidence in the clinical development programme as we advance to Phase III trials.” 

CT-388 was generally well tolerated, with gastrointestinal side effects mostly mild to moderate and consistent with other incretin-based medicines. Treatment discontinuation due to adverse events remained low at 5.9% in the active-treatment arms, compared with 1.3% in placebo-treated participants.

Roche highlighted CT-388 as a fast-tracked program within its expanding cardiometabolic portfolio and confirmed plans to rapidly advance development. Another Phase II study is underway in patients with obesity or overweight and type 2 diabetes, while the Phase III Enith1 and Enith2 obesity trials are expected to begin this quarter. Roche also views CT-388 as a potential backbone therapy in combination regimens, including with petrelintide, as it seeks to address the growing global burden of obesity and related chronic diseases.