Despite achieving far greater weight loss and blood sugar reduction, tirzepatide narrowly missed proving superior heart protection over dulaglutide in the SURPASS-CVOT trial, raising questions about whether we've hit a cardiovascular benefit ceiling with incretin drugs.
HR 0.92 — superiority missedTirzepatide reduced MACE by 8% vs dulaglutide but didn't reach statistical superiority (P=0.086), despite achieving 7% more weight loss and 0.8% better HbA1c
What the researchers found
SURPASS-CVOT compared tirzepatide to dulaglutide (not placebo) for major adverse cardiovascular events (MACE) in type 2 diabetes. Tirzepatide demonstrated noninferiority with an HR of 0.92 (95.3% CI: 0.83–1.01, P = 0.086), but superiority over dulaglutide was narrowly missed. Against an imputed placebo, tirzepatide showed a potential 28% MACE risk reduction.
Notably, tirzepatide achieved substantially better metabolic outcomes — 0.8% greater HbA1c reduction and 7% more weight loss than dulaglutide — yet this translated to only modest incremental cardiovascular benefit. Exploratory analyses showed promising signals for reduced mortality and better kidney function, but these require cautious interpretation. The disconnect between dramatic metabolic improvements and limited extra heart protection is the central finding of this commentary.
Why it matters
This raises a fundamental question for metabolic medicine: if dramatically better weight loss and blood sugar control don't proportionally improve heart outcomes, have we reached the limit of what incretin-based drugs can do for cardiovascular protection? With billions being invested in triple and multi-agonist drugs, the answer has enormous implications for drug development strategy and patient care priorities.
How the study worked
This is an expert commentary/editorial analyzing the results of the SURPASS-CVOT trial. SURPASS-CVOT was a large cardiovascular outcomes trial that used an active comparator design (tirzepatide vs dulaglutide) rather than a placebo-controlled design, reflecting the ethical reality that placebo-controlled trials are no longer appropriate when effective treatments exist. The commentary also discusses an imputed placebo analysis to estimate the absolute cardiovascular benefit of tirzepatide.
What this study cannot tell us
This is a commentary by a single author, not a primary research study. The SURPASS-CVOT trial used an active comparator rather than placebo, making it harder to demonstrate superiority since dulaglutide itself provides cardiovascular benefits. The imputed placebo analysis is a statistical estimation, not a direct comparison. The commentary notes that exploratory findings on mortality and kidney function should be interpreted cautiously.
How to read the evidence
This is an expert commentary analyzing a major cardiovascular outcomes trial (SURPASS-CVOT). While the underlying trial is high-quality evidence, this paper provides interpretation and opinion rather than new data.
When this study was published
Published in 2025, this commentary analyzes one of the most important metabolic cardiovascular trials of the decade. The findings are directly relevant to current clinical practice and ongoing drug development.
The bigger picture
The incretin drug race has been defined by achieving ever-greater weight loss and metabolic improvement. SURPASS-CVOT challenges the assumption that more weight loss automatically means more heart protection. If the cardiovascular benefit of GLP-1-based drugs has a ceiling, the industry's push toward triple agonists (like retatrutide) may need to be justified by benefits beyond heart protection — such as liver disease, kidney protection, or quality of life. This commentary suggests the field may need entirely new paradigms to further reduce cardiovascular risk in diabetes.
Questions still open
- Is there truly a cardiovascular benefit ceiling for incretin-based drugs, or would longer follow-up or higher doses of tirzepatide eventually show superiority?
- If better metabolic outcomes don't translate to proportionally better heart protection, what other mechanisms drive cardiovascular risk in type 2 diabetes?
- Should the development of triple agonists like retatrutide pivot to emphasizing liver and kidney benefits rather than cardiovascular superiority?
Common questions
Does this mean tirzepatide (Mounjaro) is worse for your heart than other diabetes drugs?
What is a 'cardiovascular ceiling' and why does it matter?
Read the original research
Can Dual Incretin Receptor Agonists Exert Better Cardiovascular Protection than Selective GLP-1 Receptor Agonists? Highlights from SURPASS-CVOT.
Diabetes therapy : research, treatment and education of diabetes and related disorders, 16(10), 1893-1898
Citation
Fadini, Gian Paolo. (2025). Can Dual Incretin Receptor Agonists Exert Better Cardiovascular Protection than Selective GLP-1 Receptor Agonists? Highlights from SURPASS-CVOT.. Diabetes therapy : research, treatment and education of diabetes and related disorders, 16(10), 1893-1898. https://doi.org/10.1007/s13300-025-01784-x