Published on November 10, 2023, 12:53 am
Weight loss drugs have garnered significant attention in recent times, and a new medication has emerged as one of the most effective options available. The U.S. Food and Drug Administration (FDA) recently approved tirzepatide, which will be sold under the brand name Zepbound, to treat overweight and obesity. Developed by Eli Lilly and Co., this drug has already shown its efficacy in treating type 2 diabetes under the name Mounjaro, with weight loss effects being a contributing factor.
It is estimated that around 70% of Americans fall into the categories of either overweight or obese, carrying significant health risks such as heart disease, diabetes, osteoarthritis, and more. Despite this alarming statistic, there haven’t been many effective medications available for the treatment of obesity. However, semaglutide (sold as Wegovy), manufactured by Novo Nordisk and approved in 2021, has helped numerous individuals lose a significant amount of weight. This success has prompted doctors to view overweight and obesity as chronic conditions requiring medical intervention.
In studies submitted to the FDA by Lilly, tirzepatide demonstrated its effectiveness in promoting weight loss among individuals who were overweight or obese and did not have diabetes. On average, these participants lost approximately 18% of their body weight compared to those taking a placebo. Participants with diabetes experienced an average weight loss of about 12%. In comparison, individuals without diabetes who were part of semaglutide trials lost an average of 15%. While these percentages may seem modest at first glance, they far surpass typical outcomes achieved through diet and exercise alone.
Zepbound is administered to patients via injection once a week over a period of up to 20 weeks until the maximum dose is reached (15 mg). The FDA has cautioned that side effects such as nausea, vomiting, hair loss, and reflux may occur with this drug. Although thyroid tumors were observed in animal studies, it remains unclear if the same risk exists for humans. As a result, individuals with a history of thyroid cancer should avoid taking tirzepatide.
Tirzepatide belongs to a class of drugs known as incretins, which mimic hormones released by the gut after meals. These hormones signal the pancreas to produce insulin, which aids in breaking down glucose from food and helps regulate blood sugar levels. Insufficient incretin production can lead to weight gain, diabetes, and other metabolic conditions. Scientists have been working for decades to develop treatments that replicate these hormones, but their short lifespan posed challenges. Dr. Daniel Skovronsky, Chief Scientific and Medical Officer and President of Lilly Research Laboratories, was part of the team that developed tirzepatide and explained that combining different incretins proved successful in improving both glucose and weight control. Tirzepatide is a combination of two highly effective incretins: glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). It is the first dual-acting weight loss drug of its kind, whereas semaglutides target a single incretin—GLP-1.
The combination of GLP-1 and GIP has proven to be powerful in promoting weight loss. Initial safety studies involving patients with type 2 diabetes showed significant weight reduction. Consequently, Lilly decided to seek FDA approval for overweight individuals and those with obesity based on these promising results. The FDA has approved tirzepatide only for individuals who are overweight (BMI between 27 and 30) with additional risk factors like high blood pressure or high cholesterol or for those who are classified as obese (BMI over 30).
The potential market for such drugs is enormous globally due to the alarming projections that around half of the world’s population will be overweight or obese in the next few decades. Treating obesity could lead to substantial cost savings for healthcare systems that currently bear the burden of treating the costly consequences associated with obesity-related health issues. Overweight and obesity contribute over $400 billion in direct costs and over $1 trillion in indirect costs to the U.S. healthcare system alone.
With the FDA’s approval of tirzepatide, doctors and patients now have access to two powerful drugs for weight loss. The availability of a growing range of effective weight loss medications may prompt doctors, patients, and insurance companies to view obesity as a chronic medical condition rather than merely a result of poor lifestyle choices. Studies demonstrate that tirzepatide can work in conjunction with diet and exercise; individuals who started with diet and exercise alone achieved an average weight loss of 6.9%, which increased to an additional 21% when tirzepatide was added. In contrast, the placebo group experienced an average weight gain of 3.3%.
Although Zepbound doses are expected to be available at pharmacies soon, some individuals may still face challenges obtaining access to this medication. Zepbound will be priced approximately 20% lower compared to