Tirzepatide (5 mg, 10 mg, 15 mg) achieved superior weight loss compared to placebo at 72 weeks of treatment in topline results from Eli Lilly and Company's SURMOUNT-1 clinical trial, with participants losing up to 22.5% (52 lb. or 24 kg) of their body weight for the efficacy. This study enrolled 2,539 participants and was the first phase 3 global registration trial evaluating the efficacy and safety of tirzepatide in adults with obesity, or overweight with at least one comorbidity, who do not have diabetes. Tirzepatide met both co-primary endpoints of superior mean per cent change in body weight from baseline and a greater percentage of participants achieving body weight reductions of at least 5% compared to placebo for both estimandsii. The study also achieved all key secondary endpoints at 72 weeks.

For the efficacy estimand, participants taking tirzepatide achieved average weight reductions of 16.0% (35 lb. or 16 kg on 5 mg), 21.4% (49 lb. or 22 kg on 10 mg) and 22.5% (52 lb. or 24 kg on 15 mg), compared to placebo (2.4%, 5 lb. or 2 kg). Additionally, 89% (5 mg) and 96% (10 mg and 15 mg) of people taking tirzepatide achieved at least 5% body weight reductions compared to 28% of those taking placebo.

"Tirzepatide is the first investigational medicine to deliver more than 20 percent weight loss on average in a phase 3 study, reinforcing our confidence in its potential to help people living with obesity," said Jeff Emmick, MD, Ph.D., vice president, product development, Lilly. "Obesity is a chronic disease that requires effective treatment options, and Lilly is working relentlessly to support people with obesity and modernize how this disease is approached. We're proud to research and develop potentially innovative treatments like tirzepatide, which helped nearly two thirds of participants on the highest dose reduce their body weight by at least 20 percent in SURMOUNT-1."

Tirzepatide is a novel investigational once-weekly GIP (glucose-dependent insulinotropic polypeptide) receptor and GLP-1 (glucagon-like peptide-1) receptor agonist, representing a new class of medicines being studied for the treatment of obesity.