INDIANAPOLIS — A new weight loss drug is the first to ever help patients lose over 20 percent of their body weight during a clinical trial, researchers report.
A team from pharmaceutical company Eli Lilly and Company say the drug tirzepatide delivered record-breaking results in the first phase 3 trial of the drug. A group of more than 2,500 people participated in the 72-week trial (16 months), taking either 5 mg, 10 mg, or 15 mg of the medication once a week. These individuals had an average body weight of 231 pounds and a body mass index (BMI) of 38, placing them all in the obese range.
Over the course of the study, patients taking 5 mg of tirzepatide lost 16 percent of their body weight. For patients taking 10 mg, they lost 21.4 percent on average and those taking 15 mg lost 22.5 percent. A staggering 96 percent of the participants taking 10 or 15 mg of the drug lost at least five percent of their total body weight, compared to just 28 percent who were taking a 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,” says Jeff Emmick, MD, Ph.D., vice president of product development at Lilly, in a media release.
What is tirzepatide?
Researchers say the drug is a once-weekly glucose-dependent insulinotropic polypeptide (GIP) receptor and glucagon-like peptide-1 (GLP-1) receptor agonist. It’s part of a new class of drugs scientists are studying for use as an obesity treatment.
Tirzepatide activates two of the body’s natural incretin hormones (GIP and GLP-1). Studies have found that GIP decreases food intake and increases energy expenditure. Researchers believe the combination of GLP-1 receptor agonism reveals even greater ties between these hormones and metabolic dysregulation.
Taking the drug only led to mild or moderate gastrointestinal-related side-effects in a portion of the patients. These symptoms included nausea, diarrhea, vomiting, and constipation. Interestingly, fewer patients from each dosage group of tirzepatide failed to complete the 72-week program than the number of participants in the placebo group (26.4%).
The team is now examining how well obese patients who also have Type 2 diabetes tolerate this drug and how well tirzepatide works as a diabetes deterrent. This follow-up trial will last for an additional 104 week (two years).
“For perspective, a 5% weight loss reduces the risk of developing diabetes by 50%, and a 10% weight loss reduces it by 80%,” says Louis J. Aronne, MD, FACP, DABOM, from Weill Cornell Medicine and an investigator in the SURMOUNT-1 trial, in a statement. “Lap band produces about 17% weight loss, and sleeve gastrectomy 25% mean weight loss. The gap between diets and bariatric surgery is being filled by medical therapy.”
“Obesity is a chronic disease that often does not receive the same standard of care as other conditions, despite its impact on physical, psychological and metabolic health, which can include increased risk of hypertension, heart disease, cancer and decreased survival,” he adds.