South San Francisco, California — January 27, 2026 — Leads & Copy — Genentech, a member of the Roche Group (SIX: RO, ROG; OTCQX: RHHBY), announced positive topline results from the CT388-103 Phase II clinical trial, which studied CT-388 for obesity treatment.
The trial revealed that weekly subcutaneous injections of CT-388, titrated up to 24 mg, led to a significant 22.5% placebo-adjusted weight loss without reaching a plateau after 48 weeks, using the efficacy estimand. The treatment-regimen estimand showed an 18.3% placebo-adjusted weight loss (p-value < 0.001).
At week 48, among participants on the 24 mg dose, 95.7% achieved at least 5% weight loss, 87% achieved at least 10%, 47.8% achieved at least 20%, and 26.1% achieved at least 30%.
The study also found that 73% of participants who were pre-diabetic at the start of the trial and treated with CT-388 at 24 mg achieved normal blood glucose levels by week 48, compared to 7.5% in the placebo group.
According to the release, the treatment was well-tolerated, with mostly mild-to-moderate gastrointestinal-related adverse events, consistent with the incretin class of medicines. The treatment discontinuation rate due to adverse events was low, at 5.9% in CT-388 arms and 1.3% in the placebo arm. The full study results will be presented at a future medical congress.
Levi Garraway, M.D., Ph.D., chief medical officer and head of Global Product Development, stated that the weight loss, combined with the safety profile, reinforces confidence in the clinical development program as it advances to Phase III trials.
Genentech is advancing potentially transformative standards of care to improve the lives of people living with cardiometabolic diseases and reduce the burden on healthcare systems.
The company designated CT-388 as a fast-track asset and accelerated its clinical development to bring this therapy to patients quickly. CT-388 is also being studied in another Phase II trial (CT388-104) to assess its efficacy, safety, and tolerability in participants with obesity or who are overweight and have type 2 diabetes. The Phase III clinical trial program of CT-388 in obesity (Enith1 and Enith2) is expected to start this quarter. CT-388 is also considered a combination asset for petrelintide.
The Phase II trial [NCT06525935] included 469 people with obesity, assessing the efficacy and safety of CT-388 at different doses. It included adults with a BMI of 30.0 kg/m2 or higher, or those overweight with a BMI between 27.0 and 30.0 kg/m2 and at least one weight-related comorbidity without type 2 diabetes. The primary endpoint was the percent change in body weight from baseline to week 48.
CT-388 is an investigational, once-weekly, subcutaneous injectable, dual GLP-1/GIP receptor agonist being developed for obesity, type 2 diabetes, and other obesity-related comorbidities. It aims to reduce appetite and regulate blood sugar by targeting and activating both receptors which integrate nutrient-derived signals to control energy homeostasis. CT-388 was designed to have potent activation of both GLP-1 and GIP receptors, but with minimal to no ß-arrestin recruitment on either receptor.
Founded 50 years ago, Genentech is a biotechnology company that discovers, develops, manufactures, and commercializes medicines. It is a member of the Roche Group, with headquarters in South San Francisco, California.
Source: Genentech
