At the recent American Diabetes Association Scientific Sessions conference, there was a great deal of buzz surrounding the new type 2 diabetes drug tirzepatide (Mounjaro).
The new drug — it was approved by the U.S. Food and Drug Administration in May and should go on sale by the end of June — might be a game changer. It is delivered as a once-weekly injection and will soon be sold in the United States under the brand name Mounjaro. When we reviewed the data on tirzepatide’s efficacy, we were forced to conclude that it “might just be the best type 2 diabetes drug ever.” And that’s just the half of it; tirzepatide is also possibly the best weight loss medication ever developed.
During the 82nd annual conference, researchers shared a deluge of new information on the drug, including many new analyses of the multiple major clinical trials that helped lead to its approval.
Here are some of the new details:
- Tirzepatide may help reduce the risk of kidney disease. This was one of the significant remaining questions regarding the efficacy of the drug. A new analysis of the SURPASS-4 trial showed that patients with type 2 diabetes and increased risks of cardiovascular disease using tirzepatide “experienced significantly fewer renal outcomes, especially new onset of macroalbuminuria,” when compared with patients that had been assigned basal insulin injections.
- Patients that achieve A1C reductions on tirzepatide continue to enjoy good results in the second year of treatment. The major phase of the SURPASS-4 trial lasted one year, but researchers followed patients for a second year to see what would happen. Those that hit A1C targets using tirzepatide were overwhelmingly likely to sustain those A1C improvements. Tirzepatide beat insulin on this measure in every patient grouping, even in the smallest dosage.
- We don’t yet have solid data on tirzepatide’s long-term effects — the drug is too new — but experts have their guesses. Using the BRAVO diabetes simulation model, experts have taken the short-term results and projected what is likely to occur for patients that use the drug for up to five years. Even in a conservative scenario, patients using tirzepatide are likely to experience significantly fewer complications, including both microvascular complications, cardiovascular disease, and early. Semaglutide, a GLP-1 receptor agonist sold under the brand names Ozempic, Rybelsus, and Wegovy, also performed very well, beating insulin and nearly matching the lowest dose of tirzepatide. Larger doses of tirzepatide, however, are predicted to confer the greatest protective health benefits.
- Tirzepatide improves insulin sensitivity. In the SURPASS-2 trial, measures of both islet cell function and insulin sensitivity improved over a period of 40 weeks. The new drug bested its rival semaglutide even at the lowest dose.
- How does tirzepatide spark so much weight loss? The drug reduces appetite in people with type 2 diabetes. Patients using the new medication eat less and lose fat mass. How do they measure this? Study participants were served lunch, asked to rate their own hunger levels, and told to eat as much as they wished. Scientists were there to weigh the leftovers.
- Tirzepatide users spend a lot of time in range and experience far less hypoglycemia than insulin users. Participants spent up to 91% of time in range, in comparison with 75% for insulin degludec, and experienced a lower coefficient of variation.
- Tirzepatide works quickly. Study participants that lowered their blood sugar to the target level did so weeks faster than those using semaglutide or insulin.
- Tirzepatide lowers blood pressure. An analysis of all five SURPASS trials found that systolic blood pressure dropped from 2.8 to 12.6 mmHg, with the larger dose of the medication delivering the biggest drop. To some extent, this was a natural result of weight loss, but weight loss didn’t explain all of the blood pressure improvements, suggesting that tirzepatide might have some beneficial independent effects on circulation.
- Males and females lose weight on tirzepatide. A post hoc analysis of all five SURPASS trials found that biological sex didn’t matter much — everyone was likely to enjoy the drug’s groundbreaking weight loss effects.
- Tirzepatide is not just for the obese: Even leaner individuals lost weight using the new drug. In an analysis of all five SURPASS trials, tirzepatide conferred weight loss “across a spectrum of mean baseline BMI values,” with larger doses leading to greater losses. Leaner patients (BMI <27 kilograms/square meter) using the lowest dose of tirzepatide lost about 13 pounds on average; extremely obese patients (≥35 kg/m2) using the highest dose lost closer to 30 pounds.
- Patients with long-standing diabetes enjoyed the same A1C reductions as those that were more recently diagnosed. Study participants that had diabetes for more than 10 years achieved the same huge blood sugar improvements as those who had diabetes for fewer than five years. Tirzepatide also works for young and old alike. This is potentially a big deal — type 2 diabetes is a stubborn condition. Those that have had it for many years are generally considered less likely to see major health improvements from pharmaceutical intensification.
As exciting as all of this is, readers may need to temper their enthusiasm. Tirzepatide, sold under the brand name Mounjaro, will be very expensive, and even if insurers decide that it’s worth covering, some patients may find it impossible to afford. Even for those with good insurance or good luck to pay for the drug, it will take some time before it is widely available. At first, the drug will be available only in the United States. We’re not sure when it will reach Canada, Europe, and elsewhere.
Read more about A1c, American Diabetes Association (ADA), GLP-1, insulin, Intensive management, low blood sugar (hypoglycemia), Mounjaro, tirzepatide, type 2 diabetes, U.S. Food & Drug Administration (FDA).