Powerful new obesity drug poised to upend the weight-loss cure

As a growing number of overweight Americans clamor for Ozempic and Wegovy drugs touted by celebrities and on TikTok to shed the pounds, an even more powerful obesity medicine is poised to upend the treatment.

Tirzepatide, an Eli Lilly and Co. drug approved for the treatment of type 2 diabetes under the brand name Mounjaro, has helped people with the disease who were overweight or obese lose up to 16 percent of their body weight, or more than 34 pounds, in nearly 17 months, the company said Thursday.

The late-stage study of the weight-loss drug adds to previous evidence that similar participants without diabetes lost up to 22 percent of their body weight in that period with weekly injections of the drug. For a typical patient on the highest dose, that meant losing more than 50 pounds.

Having diabetes makes it notoriously difficult to lose weight, said Dr. Nadia Ahmad, medical director of obesity clinical development at Lilly, which means the recent findings are particularly significant. We haven’t seen this degree of weight reduction, she said.

Based on the new findings, which have not yet been published in full, company officials said they will finalize an application to the U.S. Food and Drug Administration for accelerated approval for the sale of tyrzepatide for chronic weight management. A decision could come by the end of the year. A company spokesperson would not confirm whether the drug would be marketed for weight loss in the United States under a different brand name.

If approved for weight loss, tyrzepatide could become the most effective drug to date in an arsenal of drugs that are transforming the treatment of obesity, which affects more than 4 in 10 American adults and is linked to dozens of diseases that can lead to disability or death.

If everyone with obesity in this country lost 20 percent of their body weight, we would be taking patients off all these reflux, diabetes, high blood pressure medications, said Dr. Caroline Apovian, director of the Center for Weight Management and Wellness at Brigham and Women’s Hospital. We will not refer patients for stent replacement.

Industry analysts predict that tirzepatide could become one of the best-selling drugs of all time, with annual sales exceeding $50 billion. It is expected to surpass Novo Nordisks Ozempic, a diabetes drug used so commonly for weight loss that comedian Jimmy Kimmel joked about it at the Oscars, and Wegovy, a version of the drug also known as semaglutide approved for weight loss in the 2021. Together, those drugs earned nearly $10 billion in 2022, with prescriptions continuing to climb, company reports show.

In separate studies, tirzepatide led to greater weight loss than semaglutide, whose users lost approximately 15% of their body weight over 16 months. A head-to-head trial comparing the two drugs is planned.

Mounjaro was first approved for the treatment of diabetes last year. Since then, thousands of patients have obtained the drug from doctors and telehealth practitioners who have prescribed it off-label to help them lose weight.

In California, Matthew Barlow, a 48-year-old health technology executive, said he’s lost more than 100 pounds since November using Mounjaro and changing his diet.

Psychologically, you don’t want to eat, Barlow said. Now I can eat two bites of dessert and be satisfied.

Rather than relying solely on diet, exercise and willpower to reduce weight, tyrzepatide and other new drugs target the digestive and chemical pathways that underlie obesity, suppressing appetite and dulling the craving for food.

They’ve completely changed the landscape, said Dr. Amy Rothberg, a University of Michigan endocrinologist who leads a virtual weight-loss and diabetes program.

Research has shown that with diet and exercise alone, about a third of people will lose 5 percent or more of their body weight, said Dr. Louis Aronne, director of the Comprehensive Weight Control Center at Weill Cornell Medicine. In the latest study of tyrzepatide, more than 86% of patients using the highest dose of the drug lost at least 5% of their body weight. More than half of that dose lost at least 15%, the company said.

Obesity drugs help overcome a biological mechanism that kicks in when people diet, triggering a coordinated effort by the body to prevent weight loss.

This is a real physical phenomenon, Aaron said. There are a number of hormones that respond to reduced calorie intake.

Ozempic and Wegovy are two versions of semaglutide. That drug mimics a key gut hormone, known as GLP-1, which is activated after people eat, boosting insulin release and slowing sugar release from the liver. It delays digestion and reduces appetite, making people feel full longer.

Tirzepatide is the first drug that uses the action of two hormones, GLP-1 and GIP, for greater effects. It also targets the chemical signals sent from the gut to the brain, curbing cravings and thoughts of food.

Although the drugs appear safe, they can cause side effects, some serious. The most common reactions include diarrhea, nausea, vomiting, constipation and stomach pain. Some users have developed pancreatitis or inflammation of the pancreas, others have had gallbladder problems. The Mounjaros product description warns that it may cause thyroid cancers, including cancer.

There are other downsides: versions of semaglutide have been on the market for several years, but the long-term effects of taking overriding drugs on human metabolism are still unclear. Early evidence suggests that when people stop taking their medications, they put the weight back on.

In addition, the drugs are expensive and difficult to obtain in recent months due to intermittent shortages. Wegovy is priced at around $1,300 a month. Mounjaro used for diabetes starts at around $1,000 a month.

Apovian said that only about 20% to 30% of privately insured patients in his study find the drugs are covered. Some insurers who previously paid for drugs are issuing new rules, requiring six months of documented lifestyle changes or a certain amount of weight loss for ongoing coverage. Medicare is largely prohibited from paying for diet drugs, although there have been efforts by drug makers and congressional advocates to change that.

However, experts say the amazing effects of tyrzepatide along with Ozempic, Wegovy and other drugs underscore that losing weight isn’t just about willpower. Like hypertension, which affects about half of US adults and is managed with medication, obesity should be considered a chronic disease, not a character flaw, Aronne stressed.

What effect new drug treatments will have on the pervasive prejudice against people with obesity remains to be seen, said Rebecca Puhl, a professor at the Rudd Center for Food Policy and Health who studies weight stigma. US culture has ingrained beliefs about body weight and appearance that are hard to change, she said.

Weight stigma could persist or worsen if taking medication is equated with taking the easy way out or not trying hard enough, she said.

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