FDA Grants Tirzepatide a New Indication for Obesity Management

The US Food and Drug Administration has approved tirzepatide (Zepbound; Eli Lilly), for chronic weight management in adults with obesity or overweight and at least one weight-related condition.

Tirzepatide is the first in a new class of incretin-based agents that activate two different hormones involved in the regulation of blood sugar: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). GLP-1 increases satiety and decreases gastric emptying, while GIP is thought to affect regulation and storage of adipose tissue. The FDA approved tirzepatide in May 2022 under the trade name Mounjaro (Eli Lilly) as an adjunct to diet and exercise to improve blood sugar control in patients with type 2 diabetes.

In its announcement today, the FDA said tirzepatide received priority review and Fast Track designations for this new indication. The agent will compete with the GLP-1 receptor agonist semaglutide (Ozempic and Wegovy; Novo Nordisk), whose popularity has led to drug shortages in 2023. Later this week, the cardiovascular outcomes trial for semaglutide, SELECT, will be presented at the American Heart Association 2023 Scientific Sessions; top-line results showing a favorable impact on CV events were released in August.

Supporting data for tirzepatide come from two RCTs, including SURMOUNT-1. Both tracked weight reductions in a total of 2,519 patients who received injections of 5 mg, 10 mg, or 15 mg of tirzepatide once weekly and 958 patients who received once-weekly placebo injections, according to the FDA. Both trials, which included patients with and without diabetes, showed that after 72 weeks, weight loss was greater in the tirzepatide patients at all three doses compared with placebo. In those without diabetes, the average weight lost on the highest dose was 18% of starting body weight, while in those with diabetes the average weight lost on the highest dose was 12% of starting body weight.

Tirzepatide is administered by injection under the skin once weekly, with the dosage increasing over four to 20 weeks. Patients are eligible for the treatment if they have a BMI of 30 kg/m² or greater, or a BMI of 27 kg/m² or greater plus type 2 diabetes, hypertension, hyperlipidemia, or other weight-related condition.