Tirzepatide heart trial SURPASS-CVOT completes more than four years of follow-up
The biggest tirzepatide heart study has finished, but its findings are not public yet, so how the drug compares with an older GLP-1 medicine on cardiovascular outcomes is still unknown.
SURPASS-CVOT, a cardiovascular outcomes trial of tirzepatide, has reached its completion date after more than four years of follow-up, according to its record on ClinicalTrials.gov [1]. The study is registered as NCT04255433 and is the largest and longest trial of tirzepatide run to date [1].
Tirzepatide is the molecule sold as Mounjaro and Zepbound. The trial randomized 13,299 participants across 640 sites in 30 countries [1].
The design is unusual for this type of study. Rather than comparing tirzepatide with a placebo, SURPASS-CVOT compared it with dulaglutide 1.5 mg [1]. ClinicalTrials.gov defines an active comparator arm as a group that receives an intervention health care providers already consider effective [1]. In practical terms, everyone in the trial received an active medicine, so the study was not built to test whether tirzepatide works better than no treatment. It was built to test how tirzepatide compares with an existing injected GLP-1 medicine over a long period.
Results have not been reported. How tirzepatide compared with dulaglutide 1.5 mg on cardiovascular outcomes, and whether the two drugs differed at all on those measures, has not been disclosed. No date for releasing the findings has been announced.
Why it matters for patients
Cardiovascular outcomes trials are the studies regulators, insurers and doctors often lean on when comparing one diabetes or weight medicine with another, because they track heart-related events over years rather than weeks or months. Until this trial's results are public, there is no head-to-head cardiovascular comparison between tirzepatide and dulaglutide 1.5 mg to point to.
Tirzepatide and semaglutide are different molecules, and results from one do not automatically describe the other. Semaglutide is sold as Ozempic, Wegovy and Rybelsus, and its own cardiovascular data come from separate trials. A finding for tirzepatide in SURPASS-CVOT would apply to the drug, dose and comparison tested in that study — not to semaglutide, and not to every dose or version of tirzepatide.
The comparator also shapes what the trial can say. Because SURPASS-CVOT used an active drug rather than a placebo, its results are positioned to answer a comparison question: how did tirzepatide do next to dulaglutide 1.5 mg [1]. A placebo-controlled design would answer a different question, about performance against no active treatment. Neither kind of result tells an individual patient what to take; that depends on their own history and their prescriber's judgment.
One practical point for anyone following the news: completing a trial is not the same as publishing it. The study reaching its completion date means follow-up and data collection are finished [1]. It does not mean the numbers are available.
What happens next
ClinicalTrials.gov rules generally require sponsors to submit results about a year after a trial's primary completion date, and sponsors can request extensions to that deadline [1]. Whether an extension has been requested for SURPASS-CVOT has not been reported.
Cardiovascular outcomes results are often first presented at medical conferences and then published in a journal, but no presentation or publication for this trial has been announced. Until then, the key question — whether tirzepatide reduced heart-related events compared with dulaglutide 1.5 mg, and by how much — remains unanswered.
Sources
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