Tirzepatide: Two for One Efficacy? Diabetes + Obesity?

News from Eli Lilly and Company suggests that we may soon see a new drug that offers two-for-one efficacy – a clinical benefit in both obesity and diabetes. The company announced yesterday that tirzepatide produced good results against endpoints for both diseases in a phase 3 RCT.

In this study, called SURPASS-1, researchers tested three different doses of tirzepatide – injections of 5, 10, or 15 mg versus placebo. At the highest dose, patients lost an average of 11 percent of their initial body weight after 40 weeks. Effects on obesity were a secondary outcome in this study of type-2 diabetes.

Nonetheless, these results suggest that the same dose of tirzepatide might be effective for both diabetes and obesity.

Moving Away from Drugs That Make Obesity Worse

Coming to obesity from a background in pharmacy, we could never make sense of treating type 2 diabetes with drugs that cause weight gain. Obesity often causes diabetes. So why treat diabetes with drug that trigger more weight gain? Insulin has that potential, though careful prescribing can reduce this risk. Glitazones cause weight gain, too. Before their sales tanked due to safety concerns, sales of glitazones mounted into the billions of dollars. Insulin remains a 25 billion dollar business today.

So it’s nice to see movement toward drug therapy that helps with both conditions. GLP-1 agonists like liraglutide, dulaglutide, and semaglutide started this. SGLT2 inhibitors are also positive in this regard, though the impact on obesity is modest.

Two for One

What may be different with tirzepatide could be the dosing. With both liraglutide and semaglutide, the dose for a clinically significant effect on obesity is higher than the dose for diabetes. Among other things, that means liraglutide (Saxenda) is much more expensive for obesity than it is for diabetes.

But the story appears to be different for tirzepatide. Even at the lowest dose for diabetes (5 mg), patients lost eight percent of their initial body weight. That’s enough to be clinically meaningful.

Of course, we must take all of this with a grain of salt. These results will not be published in peer-reviewed form until next year. This study included patients who didn’t even have obesity. They were allowed into this study with a BMI as low as 23. So much more work will go into completing the picture of tirzepatied for diabetes and obesity.

Nonetheless, this is clearly good news.

Click here for the Lilly’s data in the form of a press release. For further perspective, click here and here, and here.

Two Hands Holding a Pair of Books, sketch and study by Albrecht Durer / WikiArt

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December 10, 2020