Hot off the presses! Topline data was just released on the up-and-coming medication tirzepatide as a weight management medication. And the results are very impressive!
As blogged previously, tirzepatide is a once-weekly dual GIP/GLP1 receptor agonist that has proven to be very powerful as a treatment for type 2 diabetes in the SURPASS clinical trial program. In these studies, tirzepatide was also found to result in a very impressive weight loss. (Note: tirzepatide is not yet available for clinical use.)
Now, we have the first topline results from the SURMOUNT clinical trial program, evaluating tirzepatide as a weight loss medication in people without diabetes. The study enrolled 2,539 participants, and randomized them to receive tirzepatide 5mg, 10mg, 15mg, or placebo.
After 72 weeks, they found an average weight loss of:
(scientists/researchers: below data are using the more conservative treatment-regimen estimand; the efficacy estimand results are a little higher)
- 15% with tirzepatide 5mg
- 19.5% with tirzepatide 10mg
- 20.9% with tirzepatide 15mg (almost 50lb)
- 3.1% with placebo
- 30% of people achieved at least 20% weight loss with tirzepatide 5mg
- 50% of people achieved at least 20% weight loss with tirzepatide 10mg
- 57% of people achieved at least 20% weight loss with tirzepatide 15mg
- 3.1% of people achieved at least 20% weight loss with placebo
The overall safety and tolerability was reported as being similar to what we see in the GLP1 class of medications. Gastrointestinal side effects were the most common (nausea in 25-33% of people on tirzepatide vs 10% in placebo, diarrhea in 19-23% on tirzepatide vs 7% in placebo, constipation in 12-17% vs 6% in placebo, vomiting in 8-12% vs 2% in placebo). These side effects were generally mild to moderate in severity, and usually during the dose escalation period.
Rates of discontinuation of treatment due to adverse events was 4.3% with tirzepatide 5mg, 7.1% with tirzepatide 10mg, 6.2% with tirzepatide 15mg, and 2.6% with placebo.
Many more people on placebo stopped study medication for any reason (26%) than those on tirzepatide (14-16%), probably due to participant frustration with lack of weight benefit on placebo.
I really look forward to seeing the study published, so we can learn more about these exciting data. I will be very keen to see the additional 2-year extension of this study in people with prediabetes, to evaluate tirzepatide’s long term effect on weight and diabetes prevention. Importantly, we also need to learn more details about side effects.
BOTTOM LINE: This is the first time that a large clinical trial of a potential weight loss medication shows an average weight loss of over 20%, approaching the amount of weight loss success that we see with bariatric surgery. Another step forward in the obesity field!
Disclaimer: I was an investigator in the SURPASS clinical trial program. The SURPASS and SURMOUNT trials are conducted by Eli Lilly, the makers of tirzepatide. I receive honoraria as a continuing medical education speaker and consultant from the makers of tirzepatide (Eli Lilly).
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