Patients taking Mounjaro were more than three times likelier to lose at least 15% of their body weight than those on Ozempic or Wegovy.
Tirzepatide, sold as Mounjaro, has beaten semaglutide for speed and quantity of weight loss in the first large head-to-head study.
The study was conducted by researchers from Truveta Inc., a company that, according to Bloomberg, “designs and develops data platform that aims to help researchers and patients”.
They used electronic health record data from 35 US states to find a sample of more than 18,000 patients with a recent first prescription for tirzepatide or semaglutide. They compared their likelihood of achieving at least 5%, 10% and 15% weight loss, and percentage change in weight at three, six and 12 months.
The researchers did not have access to dosages actually taken. The on-label standard full doses for type 2 diabetes in the US are 0.5mg for semaglutide and 5mg for tirzepatide (which was only approved for diabetes at the time).
Patients on tirzepatide were 75% more likely to lose at least 5% of their weight, 2.5 times more likely to lose at least 10% and 3.2 times more likely to lose at least 15%.
Tirzepatide also worked faster, with greater mean weight changes at three, six and 12-month intervals.
Rates of moderate to severe gastrointestinal adverse events (bowel obstruction, cholecystitis, cholelithiasis, gastroenteritis, gastroparesis, and pancreatitis) were similar on the two drugs.
Just over half the patients in both groups discontinued their drug during follow-up.
The groups were propensity matched, as those on tirzepatide were younger, more often female, white and college-educated, with a lower prevalence of type 2 diabetes and most other comorbidities.
Baseline weight was similar in both groups before matching, however. Mean baseline weight in the final sample was 110kg.
There were greater weight reductions in patients without type 2 diabetes. The reasons for this weren’t clear, but the authors suggested “patients with and without T2D may have differing motivation levels for weight loss and may engage in other weight loss activities differentially”.
