FDA Approves New Weight Loss Drug: Zepbound

On November 8, 2023, the United States Food and Drug Administration (FDA) approved Eli Lilly’s newest weight loss drug, Zepbound. The newly approved drug uses the same active ingredient as Mounjaro, tirzepatide, which acts as a glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) agonist.

The FDA notes that roughly 70% of adults in the US are overweight or obese.

“Obesity and overweight are serious conditions that can be associated with some of the leading causes of death such as heart disease, stroke, and diabetes,” said John Sharretts, MD, director of the Division of Diabetes, Lipid Disorders, and Obesity in the FDA’s Center for Drug Evaluation and Research, in the release. “In light of increasing rates of both obesity and overweight in the United States, today’s approval addresses an unmet medical need.” 

The approval was based on data from two randomized, double-blind, placebo-controlled studies on over 3,000 overweight or obese adults. One trial recruited adults without type 2 diabetes, while the other chose to include patients with type 2 diabetes.

Patients were randomized to three experimental groups — which received 5, 10, or 15 mg of the drug — or a control group that received a placebo.

In the trial that excluded patients with type 2 diabetes, the average starting body weight was 231 lbs. However, patients taking the highest dose of Zepbound achieved an 18% body weight reduction over 72 weeks. Meanwhile, patients with type 2 diabetes lost approximately 12% of their body weight.

Additionally, Eli Lilly notes that the researchers identified improvements in weight-related conditions, including cholesterol changes and blood pressure reduction. However, the drug has not been approved to treat these conditions.

Although the results of the clinical trials are promising, they also highlighted potential risks associated with the medication. Common side effects include nausea, vomiting, diarrhea, constipation, abdominal pain, injection site reactions, fatigue, burping, hair loss, and gastroesophageal reflux disease.

Beyond the more common side effects, the FDA also notes that there may be an elevated risk of thyroid cancer for patients taking this drug, advising patients with a personal or family history of medullary thyroid cancer or multiple endocrine neoplasia syndrome type 2 to avoid the medication.

According to the FDA press release, the drug is approved for overweight or obese patients with a body mass index over 27 who have one or more weight-related conditions, such as high blood pressure, type 2 diabetes, or high cholesterol. Like other weight loss drugs on the market, this medication is not meant to be used alone. Patients looking to lose weight and effectively manage conditions that come with excess weight should also make lifestyle changes, including eating a healthy diet and engaging in regular physical activity.

Like Ozempic and other weight loss drugs, Zepbound is delivered as a once-weekly subcutaneous injection. The medication can be prescribed for three target doses, including 5, 10, or 15 mg; however, patients should begin on a lower dose and be increased to the target dose over 4–20 weeks. Lilly will make the drug available in the following doses: 2.5 , 5, 7.5, 10, 12.5, and 15 mg.

The company revealed that the medication will be listed at $1,059.87 per unit; however, insurance coverage may result in lower out-of-pocket patient payments. 

Despite the hefty list price, Lilly maintains that the drug is cheaper than semaglutide alternatives and emphasizes the company’s commitment to accessibility.

"Far too many hurdles continue to prevent people living with obesity from accessing obesity treatments that could lead to significant weight loss," said Mike Mason, executive vice president and president of Lilly Diabetes and Obesity, in the company announcement. "Broader access to these medicines is critical, which is why Lilly is committed to working with healthcare, government, and industry partners to ensure people who may benefit from Zepbound can access it."