Eli Lilly’s Mounjaro shows similar heart health benefits as Trulicity

Eli Lilly on Thursday said its blockbuster diabetes drug Mounjaro showed heart health benefits in a late-stage trial directly comparing it to the company’s older diabetes treatment, Trulicity.

Mounjaro met the study’s main goal of showing that it wasn’t any worse than Trulicity at treating people with Type 2 diabetes and established cardiovascular disease. Eli Lilly said it believes the new data bolsters the case for Mounjaro to be prescribers’ first choice for patients with Type 2 diabetes, who are twice as likely to have heart disease or stroke as those without the disease.

The results come as Trulicity – also a top-selling drug for Eli Lilly – faces a patent expiration in 2027, which could further boost Mounjaro’s position in the diabetes market. 

Mounjaro met the main goal of the nearly five-year study, reducing the risk of cardiovascular death, heart attack or stroke by 8% when compared to Trulicity in adults with Type 2 diabetes and cardiovascular disease. But shares of Eli Lilly fell nearly 2% in premarket trading Thursday, as those results did not meet some analysts’ benchmarks for being considered superior to Trulicity. 

Still, the company said Mounjaro showed additional, “more comprehensive” benefits over Trulicity in the trial, including a 16% lower rate of death from any cause and greater kidney protection. It was the longest and largest trial to date on tirzepatide, the active ingredient in Mounjaro, enrolling more than 13,000 people. 

Some clinicians said the results, particularly the lowered risk of cardiovascular events, aren’t surprising, as they assumed Mounjaro would be able to offer cardiovascular benefits.

But the difference in the rate of death from any cause between Mounjaro and Trulicity is “really quite profound” and “definitely something clinically meaningful to us as clinicians,” said Dr. David Broome, clinical assistant professor at the division of metabolism, endocrinology and diabetes at the University of Michigan’s department of internal medicine.

He said the data helped quantify the difference between Mounjaro and Trulicity, which will further help providers and patients determine the best treatment to move forward with in their shared decision-making. Broome said those prescribing decisions between patients and providers will ultimately depend on several factors, such as their insurance coverage, the side effects of a given drug and how well the patient tolerates them.

Dr. Howard Weintraub, clinical director of the Center for the Prevention of Cardiovascular Disease at NYU Langone Heart, called Mounjaro a “winner” in the trial, with the only downside coming from it having slightly more side effects than Trulicity. But he said the results may not motivate more people to start Mounjaro, and that the drug’s higher list price may deter insurers from covering it if it isn’t substantially better than Trulicity.

Weintraub said he expects there to be a lot of “digging” into the data when the full results are presented at a European medical meeting and published in a peer-reviewed journal in the fall.

Eli Lilly saw the trial results as an indicator that clinicians should choose Mounjaro for the patient group.

“It strengthens the overall story. In my mind, it raises the question of, ‘Why wouldn’t you choose Mounjaro?'” Ken Custer, president of Lilly Cardiometabolic Health, said in an interview. 

The results “take away any doubt of why this is the right medicine for a patient with Type 2 diabetes and Type 2 diabetes with cardiovascular risk,” he said, adding that it “makes it even harder to say no to covering this medicine for patients.”

The results also come as Eli Lilly solidifies its lead over Novo Nordisk in the booming market for weight loss and diabetes drugs. Studies from both companies have shown the added health benefits of their drugs for conditions such as obstructive sleep apnea and chronic kidney disease. 

Eli Lilly plans to submit the heart health data to global regulators by the end of the year, and the company said that could lead to approvals — and by extension insurance coverage — of Mounjaro for this purpose in 2026. Any approvals would not apply to Eli Lilly’s weight loss drug Zepbound, which shares the same active ingredient as Mounjaro but is specifically cleared for patients with obesity and not diabetes. 

The company is currently studying Zepbound’s cardiovascular benefits in patients with obesity and established cardiovascular disease. The phase three trial is expected to wrap up in 2027, according to Eli Lilly’s website. 

Even if regulators approve Mounjaro for treating heart disease in patients with Type 2 diabetes, it may not significantly expand use of the drug. That’s because Mounjaro’s current approval for Type 2 diabetes already covers many of those patients: Around 30% of people with Type 2 diabetes also have cardiovascular disease, according to the Heart Foundation. 

In a June research note ahead of the data, TD Cowen analyst Steve Scala said he believes uptake of tirzeptide “would be largely unaffected” if it shows similar heart health benefits as Trulicity. 

Tirzepatide is already “gaining significant adoption” in the market due to its “strong profile,” Leerink Partners analyst David Risinger said in a separate note in June. He said experts agreed that regardless of whether tirzepatide’s cardiovascular benefits were superior or matched those of Trulicity in the study, the results “would not significantly alter” the decisions of doctors. 

Mounjaro showed greater improvements than Trulicity did when it came to some cardiovascular measures and lowering body weight and A1C, which is a measure of blood sugar levels.

The safety data of both Mounjaro and Trulicity were generally consistent with what has been observed in the past. The most commonly reported adverse events for both drugs were gastrointestinal-related and generally mild to moderate in severity. 

— CNBC’s Angelica Peebles contributed to this report.