A new drug called tirzepatide has proved to help overweight and obese participants lose up to 22.5 percent of their total body weight over the 72-week trial.
These drugs are designed to emulate the action of a naturally occurring hormone called glucagon-like peptide-1 (GLP-1), which is produced by intestinal cells.
Instead of directly acting on GLP-1 receptors, tirzepatide is a molecule designed to simultaneously copy the role of a slightly different hormone called gastric inhibitory polypeptide (GIP). Early studies found this unique molecule results in a dual-action on both GLP-1 and GIP receptors, leading to greater decreases in food intake and greater increases in energy expenditure.
Based on successful Phase 3 trial results, that approval is expected to come over the next few months.
This new data, was announced in a press release from pharma company Eli Lilly.
The Phase 3 trial, called SURMOUNT-1, enrolled 2,539 subjects across nine countries, with the mean body weight of each participant being 231 lb (105 kg). Each participant was randomly, and blindly, put into one of four groups: tirzepatide 5 mg, 10 mg or 15 mg, or placebo. The treatment involved one subcutaneous injection of the drug each week.
At the end of the 72-week program, those on the lowest dose had lost an average of 16 percent of their body weight, while those on the highest dose dropped 22.5 percent. This compared to just a 2.4-percent drop in body weight for those taking the 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, vice president of product development at Eli Lilly. “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.”
SURMOUNT-1 is part of a larger series of six global trials looking at the effects of tirzepatide on obesity.