Tirzepatide and Semaglutide Begin to Compete

Semaglutide is getting a lot of attention right now because of its impressive effectiveness for treating obesity. But it may not have the spotlight all to itself for long. A new study in the New England Journal of Medicine tells us that tirzepatide will be giving semaglutide some serious competition. This study was for treating diabetes. Nonetheless, tirzepatide delivered impressive results for outcomes related to obesity. On the highest dose of tirzepatide, patients lost 13 percent of body weight at the end of 40 weeks.

That was about twice as much weight loss as recorded in patients receiving the 1 mg dose of semaglutide. Of course, a higher dose of 2.4 mg of semaglutide is what is indicated for treating obesity.

Dosing for Diabetes vs. Obesity

Let’s be clear. This was a study of these drugs for treating type 2 diabetes. Semaglutide requires a higher dose for treating obesity and at that high dose, it yields better outcomes. Furthermore, research on tirzepatide is in its early stages. So we have a lot yet to learn.

With all that said, though, 13 percent weight loss is impressive. And getting that degree of effectiveness for an obesity endpoint in a diabetes trial is very good. One of the key issues with semaglutide is its high cost for obesity treatment. Because the semaglutide dose for obesity is more than twice as high as it is for diabetes, the cost is much higher than the cost for treating diabetes.

Time will tell if the dosing and pricing for tirzepatide translates into a better value for treating obesity.

“Breaking New Ground”

For diabetes, tirzepatide is looking like a winner. In an NEJM editorial, Katherine Tuttle offers a glowing assessment of this development:

“The novel concept of combining a glucose-dependent insulinotropic polypeptide with a glucagon-like peptide-1 (GLP-1) receptor agonist takes incretin therapeutic agents to a new level.”

In short, she says the unique dual action of tirzepatide is ground-breaking.

Much to Learn

Without a doubt, we still have much to learn about tirzepatide. When it goes into FDA later this year for approval, it will get careful scrutiny. One thing to pay attention to is the safety profile. Overall tolerability was similar for both tirzepatide and semaglutide. However, for tirzepatide, serious adverse events were more common. Five to seven percent of tirzepatide had a serious AE, compared to only three percent for semaglutide. This may be an artifact of this particular study, but it bears watching.

We may see tirzepatide approved for treating type 2 diabetes next year. An indication for obesity will take a few more years after that. This means competition to provide better options for treating obesity is growing, and that is definitely good news.

Click here for the study, here for the editorial, and here for further perspective.

In the Racing Shell, painting by Joaquín Sorolla / WikiArt

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June 26, 2021