Eli Lilly's dual GIP/GLP-1 receptor agonist tirzepatide has already demonstrated its benefits in patients with diabetes, obesity, sleep apnea and fatty liver disease. Now, Lilly is eying another major market with positive results from a trial in patients with heart failure (HF).
In the phase 3 SUMMIT trial, Lilly's tirzepatide reduced the risk of adverse HF outcomes—such as hospitalization or cardiovascular death—by 38% compared with placebo. The study enrolled 731 patients with HF with preserved ejection fraction (HFpEF) and obesity.
Besides meeting that primary endpoint of a reduction in HF outcomes, Lilly said tirzepatide improved patients' HF symptoms and physical limitations versus placebo, the trial's other primary endpoint. For that endpoint, investigators used the Kansas City Cardiomyopathy Questionnaire Clinical Summary Score.
For patients with HFpEF, the heart's left ventricle becomes stiff and doesn't allow the heart to fill properly between beats, affecting blood flow. HFpEF cases make up nearly half of all heart failure cases, according to Lilly. Symptoms include fatigue, shortness of breath, inability to exercise and swelling.
Importantly, nearly 60% of HFpEF patients also live with obesity, Lilly's senior vice president of product development, Jeff Emmick, M.D., Ph.D., said in a statement.
In addition to the trial's two primary endpoints, tirzepatide met all secondary endpoints, including one measure of improvement in exercise capacity, Lilly said. Further, patients on tirzepatide lost significantly more weight—15.7% on average prior to treatment discontinuation—compared to 2.2% for placebo.
Lilly said it plans to share the results at an upcoming medical meeting and submit them to a peer-reviewed journal.
Lilly's tirzepatide is already approved in Type 2 diabetes as Mounjaro and obesity as Zepbound and is set to make serious blockbuster sales in those two indications alone. The company plans to submit the SUMMIT study results to the FDA and other regulators "starting later this year," Lilly said in its release, potentially adding to the drug's sales trajectory.
On the market, tirzepatide is going up against Novo's rival GLP-1 drug semaglutide, which is branded as Ozempic and Rybelsus in diabetes and Wegovy in obesity. A year ago, Novo touted semaglutide's benefits in a late-stage trial in patients with HFpEF, and the FDA approved a cardio label expansion for the drug in March.
Facing seemingly unlimited demand for the rival medicines, Novo and Lilly have spent billions in recent years building global manufacturing capacity. For Lilly, high tirzepatide demand prompted the company's recent decision to pledge more than $9 billion to expand in its home state of Indiana.