Eli Lilly and Company presented Phase 3 clinical trial findings on November 16, 2026, at the American Heart Association (AHA) Scientific Sessions in Chicago, Illinois, concurrently published in the New England Journal of Medicine. The SUMMIT registration trial established that dual GIP/GLP-1 receptor agonist tirzepatide reduced the combined risk of worsening heart failure events and cardiovascular death by 38% among adults diagnosed with heart failure with preserved ejection fraction (HFpEF) and obesity.
The double-blind, randomized, placebo-controlled SUMMIT investigation (NCT04847557) enrolled 731 ambulatory adult patients across clinical sites in North America, Europe, and Asia. Over a median clinical follow-up duration of 104 weeks, once-weekly subcutaneous tirzepatide demonstrated statistically significant improvements across co-primary endpoints. Compared to standard-of-care placebo arms, tirzepatide administration achieved a 38% relative risk reduction in the composite primary endpoint of adjudicated heart failure events requiring urgent medical intervention or cardiovascular mortality (hazard ratio = 0.62; p < 0.001). Isolated analyses revealed a 56% reduction in heart failure hospitalizations.
Principal investigator Dr. Milton Packer stated: "These results indicate tirzepatide produced meaningful benefits for people living with heart failure with preserved ejection fraction and obesity, changing the clinical trajectory of the disease in patients with HFpEF and obesity." Patients randomized to tirzepatide experienced mean weight reductions of 13.9% at 52 weeks and 15.7% at 104 weeks, compared with a 2.2% adjustment observed in placebo cohorts.
Eli Lilly officially confirmed the submission of supplemental New Drug Applications to the United States FDA and the European Medicines Agency (EMA) seeking regulatory approval for HFpEF indications in obese adults. With more than 3.0 million individuals in the United States afflicted by obesity-related HFpEF, commercial approval would establish the first specialized pharmaceutical therapy approved specifically to modify disease progression in this patient demographic.
