Clinical trial participants who took the drug lost up to 52 lb., or 24 kg, in the 72-week, phase 3 study.
Tirzepatide achieved superior weight loss compared with the placebo at 72 weeks of treatment in topline results from the SURMOUNT-1 clinical trial, Eli Lilly and Company said in a statement.
“Tirzepatide delivered impressive body weight reductions in SURMOUNT-1, which could represent an important step forward for helping the patient and physician partnership treat this complex disease,” Louis Aronne, MD, FACP, DABOM, director of the Comprehensive Weight Control Center at New York-Presbyterian/Weill Cornell Medical Center, said in the statement.
Investigators found that individuals in the study lost up to 22.5% of their body weight. The average weight reduction for individuals was 16% on the 5-mg dosage, 21.4% on the 10-mg dosage, and 22.5% on the 15-mg dosage compared with the placebo.
Additionally, 89% and 96% of individuals who were taking 10 mg and 15 mg of tirzepatide, respectively, achieved at least 5% body weight reductions compared with 28% of those taking the placebo.
In a key secondary endpoint, approximately 55% of individuals taking the 10-mg dosage and 63% taking the 15-mg dosage achieved at least 20% body weight reductions compared with 1.3% of those taking the placebo. Additionally, 32% of individuals taking the 5-mg dose achieved at least 20% body weight reductions, which was not controlled for type 1 error. The mean baseline body weight of individuals was 231 lb.
The overall safety and tolerability profile of tirzepatide was similar to other incretin-based therapies approved for the treatment of obesity. The most common adverse events (AEs) were gastrointestinal-related and were generally mild to moderate in severity, usually occurring during the dose-escalation period.
For those treated with tirzepatide, the AEs included constipation, diarrhea, nausea, and vomiting, which were more frequent compared with the placebo.
The treatment discontinuation rates because of AEs were 4.3% on the 5-mg dosage, 7.1% at 10 mg, 6.2% at 15 mg, and 2.6% for the placebo. The overall treatment discontinuation rates were 14.3% on the 5-mg dosage, 16.4% at 10 mg, 15.1% at 15 mg, and 26.4% for the placebo.
“Tirzepatide is the first investigational medicine to deliver more than 20% weight loss on average in a phase 3 study, reinforcing our confidence in its potential to help people living with obesity,” Jeff Emmick, MD, PhD, vice president of product development at Lilly, said in the statement.
Investigators included 2539 study participants to evaluate the efficacy and safety of tirzepatide in individuals who were obese or overweight with at least 1 comorbidity who do not have diabetes.
Individuals who had pre-diabetes at the study commencement will remain enrolled in SURMOUNT-1 for an additional 104 weeks of treatment following the initial 72-week completion date to evaluate the impact on body weight and the potential differences in progression to type 2 diabetes at 3 years of treatment with tirzepatide compared with the placebo.
Tirzepatide is a novel investigational once-a-week glucose-dependent insulinotropic polypeptide receptor and glucagon-like peptide-1 receptor agonist that is being studied for the treatment of obesity.
Lilly's tirzepatide delivered up to 22.5% weight loss in adults with obesity or overweight in SURMOUNT-1. Lilly. News release. April 28, 2022. Accessed April 29, 2022. https://investor.lilly.com/news-releases/news-release-details/lillys-tirzepatide-delivered-225-weight-loss-adults-obesity-or