Tirzepatide and the Search for Better Obesity Treatment

When NEJM recently published impressive results for a new obesity treatment, it caused quite a stir. Now it looks like semaglutide might have some serious competition coming right behind it. Late last week, Lilly announced results for two phase 3 studies of tirzepatide. These were both studies for type-2 diabetes. Effects on body weight were important secondary outcomes and they were impressive indeed. In the SURPASS-3 study, patients on the highest dose lost 14 percent of body weight. In the SURPASS-5 study, they lost 12 percent. Even though these tirzepatide studies are not for obesity, the results are quite impressive.

These results add to results announced late last year from the first phase 3 study with tirzepatide.

Different Patient Populations

Because obesity was not the primary focus of these studies, the results are not directly comparable to semaglutide for obesity. In the SURPASS-5 study, patients did not have to have overweight or obesity to enter the trial. For the SURPASS-3 study, they did.

It is also worth noting that these results came at the same doses that are effective for type-2 diabetes. With semaglutide, the dosing for obesity is higher than it is for diabetes. So seeing weight outomes in this study with tirzepatide similar to those seen with semaglutide for obesity is encouraging.

Playing Catch Up

Clearly, tirzepatide is a few years behind semaglutide for obesity. Semaglutide is already approved for treating diabetes, both as an injection and as a tablet. FDA is reviewing it for obesity as a weekly injection and may approve it later this year if all goes well.

On the other hand, Lilly plans its first FDA submission for tirzepatide in diabetes later this year. Studies of tirzepatide for obesity will not be complete before 2024. So Lilly will be playing catch up.

Options Are Good

Whatever the timing, it will be good to have more options for effectively treating obesity. Plus, we should remember the effective dose for obesity may be the same as it is for diabetes. So if tirzepatide enters the market for diabetes next year, it may be a very good option for patients with both diabetes and obesity. The dual effectiveness could mean less opportunity for insurers to discriminate against patients who have diabetes and need an effective treatment for obesity.

Speaking of options, another new drug – known as AM833 – is entering phase 3 studies in combination with semaglutide this year. Positive results for that study could mean further gains in effective treatment for obesity.

The search for better options in obesity care is becoming quite interesting.

Click here for the announcement from Lilly on their clinical trial results. Click here and here for further reporting.

Searchlights, painting by C. R. W. Nevinson / flickr

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February 22, 2021