Tirzepatide, developed by the American pharmaceutical company Eli Lilly and Company (Lilly), is a weekly injection that promotes weight loss by mimicking the effects of natural hormones called incretins. These hormones lower blood sugar after eating, as well as regulating the metabolic processes related to digestion.
In the case of tirzepatide, which is not yet available on the market pending further clinical study, the drug is a synthetic combination of two particular incretins, called GLP-1 (glucagon-1-like peptide) and GIP. (glucose-dependent insulinotropic polypeptide). ).
The old hormone, GLP-1, is the basis of the semaglutide diabetes drug, which was approved in the United States as a weight loss drug in 2021, which was the first time the FDA had endorsed a new treatment. for weight loss in several years. years.
This approval was granted based on the results described as a “game changer” for weight loss, but it seems that the formulation of tirzepatide, thanks to the addition of GIP together with GLP-1, could change the game’s weight loss. we.
In the Phase 3 results of the ongoing SURMOUNT-1 clinical trial investigating the effects of tirzepatide, the researchers enrolled 2,539 overweight or obese participants (with weight-related comorbidity but no type 2 diabetes).
Participants received tirzepatide or a placebo over 72 weeks, along with support for a low-calorie diet and increased levels of physical activity.
Tirzepatide was administered in one of three different doses (5, 10, or 15 milligrams per weekly injection), but all three groups saw significant levels of weight loss throughout the study.
At the highest dose (15 mg), participants saw an average weight reduction of 22.5 percent of their body weight (24 kg or 52 pounds), while the 10 mg dose achieved a weight loss of 21.4 percent (22 kg or 49 lbs) and 5 mg. saw a 16 percent reduction in body weight (16 kg or 35 pounds).
In comparison, the placebo group lost only 2.4 percent of its body weight (2 kg or 5 pounds). Previously, semaglutide weight loss trials had an average of approximately 17 percent weight loss.
“Tirzepatide is the first research drug to deliver more than 20% more weight loss on average in a Phase 3 study,” says clinical research physician Jeff Emmick, Lilly’s vice president of product development.
Although the results have not yet been reviewed in pairs, Lilly says they will be presented for this consideration in the future. Meanwhile, the study of the SURMOUNT-1 trial is ongoing, along with the related SURMOUNT trials, the results of which are expected to be announced in 2023.
However, we already know that tirzepatide does not agree with everyone who takes it. Although the mean weight loss results appear to slightly outweigh semaglutide treatment and are roughly equal to what patients can expect from bariatric surgery, some participants in the tirzepatid arm experienced adverse effects.
Depending on the dose, up to one-third of the tirzepatide group experienced nausea, while diarrhea was also relatively common (for 18.7-23% of participants). Some people also experienced vomiting and constipation, although it is worth noting that only a small percentage of participants dropped out of the study because of these effects.
Another potential barrier to the stomach of tirzepatide is the question of price, assuming that the results of subsequent research convince the FDA to approve the drug for patients with weight loss. (The drug has already been submitted for regulatory review for the treatment of diabetes.)
As others have pointed out, semaglutide, sold as a weight-loss drug under the brand name Wegovy by the Danish pharmaceutical company Novo Nordisk, sells for more than $ 1,300 a month, and very few patients can afford such an expensive drug. especially when medications such as this are rarely covered by health insurance.
If tirzepatide follows a similar pricing strategy, after its expected future release but not yet assured, this could be another case of a potentially bright and life-changing drug that many people will unfortunately not be able to buy.
“The drugs seem fantastic, but Wegovy is expensive, and so are the others,” neuroscience and obesity researcher Stephan Guyenet told Gizmodo.
“This is especially true in the US, where Wegovy costs about four times as much as in other countries. So the main issue becomes access.”
Aside from the economy, the impressive results of these drugs, however, suggest that we could soon transform the treatment of obesity, a complex and damaging epidemic that has been under our control for decades.
If we achieve that promise and ensure equitable access to this new generation of obesity drugs, we will improve the health of millions of people around the world, researchers say.
“This is extremely exciting, although preliminary data show weight loss at the level of bariatric surgery of a drug, which probably offers many other metabolic benefits,” said Scott Kahan, director of the National Center for Weight and Wellness. Washington, DC, and Healio. .
“The continued development of tirzepatide and similar agents could portend a radical shift in the treatment of obesity, similar to how the management of cholesterol and heart disease was transformed with the advent of statin drugs and how HIV management was transformed with antiretroviral drugs. ”