No result has been published from this trial, and none is due for about a year. That is the single most useful thing to know about SURMOUNT-MMO, because it is the trial that would settle whether tirzepatide prevents heart attacks, strokes and deaths in people who have obesity and do not have diabetes — and until it reports, every claim in that direction is borrowed from somewhere else. Semaglutide already has such a result, described in the SELECT article. Tirzepatide does not.
What is being run
The registry record describes a phase 3, randomized, parallel-group trial with double masking of participants and investigators, comparing once-weekly tirzepatide escalated to a maximum tolerated dose against a matched placebo. Actual enrollment is 15,374 participants, recorded across 671 site entries in 28 countries.[2] The trial’s own design paper, published while recruitment was closing, describes the target as roughly 15,000 participants at 664 sites across 27 countries.[1] Those figures are the plan and the registry’s are the outturn.
The primary endpoint is time to the first occurrence of any component of a five-part composite: death from any cause, nonfatal myocardial infarction, nonfatal stroke, coronary revascularization, or a heart-failure event, followed for up to five years.[2] The design paper states the same composite and adds the trial’s positioning: it is the first outcome trial of an incretin medication to assess both primary and secondary cardiovascular prevention in one protocol.[1]
Secondary endpoints include time to onset of type 2 diabetes, change in estimated glomerular filtration rate, the narrower three-part composite of cardiovascular death with nonfatal myocardial infarction and nonfatal stroke, time to death from any cause, time to cardiovascular death, and the physical functioning domain of a quality-of-life instrument at two years.[2] It is an event-driven trial, so the reporting date depends on how many of those events accumulate rather than on the calendar alone.[1]
Who is eligible, and who is deliberately excluded
Entry requires an age of at least 40 and a body-mass index of at least 27. Beyond that the protocol splits into two routes. One is established cardiovascular disease — coronary artery disease, cerebrovascular disease or peripheral arterial disease. The other is primary prevention, which requires a count of risk factors that rises with age and differs by sex: women aged 55 to 69 and men aged 50 to 64 need at least three, while women aged 70 or older and men aged 65 or older need at least two.[2]
The exclusions matter as much. Type 1 and type 2 diabetes are both excluded, as is laboratory evidence of diabetes at screening — a glycated hemoglobin of 6.5% or higher, or a fasting glucose of 126 mg/dL or higher. Also excluded are a myocardial infarction, acute coronary syndrome, stroke, revascularization or acute decompensated heart failure within 90 days of screening; a history of acute or chronic pancreatitis; a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia type 2; significant gastroparesis or planned bariatric surgery; and any malignancy within the previous five years.[2]
That set of criteria is what makes the trial interesting and what limits it. Excluding diabetes removes the population in which incretin cardiovascular benefit is best established, which is the point — and it also means the result, whenever it arrives, will not transfer automatically to anyone whose screening labs put them over the diabetes line, a distinction drawn in the two-indication article.
The timeline, read from the record
The registry records an actual start date of 11 October 2022, a status of active and no longer recruiting, and both primary completion and overall completion as estimated October 2027. No results have been posted, and the results-first-posted field is empty.[2] A PubMed search returns the rationale-and-design paper and commentary on it; there is no results publication of any kind.
So the honest statement of what this trial has shown is: nothing yet. It has no reported primary endpoint, no treatment difference, no confidence interval, no discontinuation rate and no adverse-event table, because none of those has been released. Anyone quoting a cardiovascular figure for tirzepatide in obesity is quoting something other than SURMOUNT-MMO, and the rest of this page is a census of what that something is.
What has reported: an active-comparator trial in diabetes
SURPASS-CVOT randomized 13,299 patients with type 2 diabetes and atherosclerotic cardiovascular disease to weekly tirzepatide at up to 15 mg or to dulaglutide 1.5 mg; 134 were excluded and the modified intention-to-treat population was 6,586 against 6,579. The primary endpoint — cardiovascular death, myocardial infarction or stroke — occurred in 801 patients (12.2%) on tirzepatide and 862 (13.1%) on dulaglutide: hazard ratio 0.92, 95.3% confidence interval 0.83 to 1.01, P = 0.003 for noninferiority against a margin of 1.05 and P = 0.09 for superiority.[3]
Three features of that design disqualify it as a stand-in for SURMOUNT-MMO. There was no placebo arm; the comparator was an agent already shown to reduce cardiovascular events, so the trial asked whether tirzepatide is at least as good rather than whether it helps. The population had diabetes, which SURMOUNT-MMO excludes. And the test that would license a benefit claim was run and did not pass.
A post hoc analysis widened the endpoint to a six-part cardiorenal composite and found it in 1,559 tirzepatide-treated patients (23.7%) against 1,803 on dulaglutide (27.4%), a hazard ratio of 0.84 (95% CI, 0.79 to 0.90; P < .001) over a median treatment duration of 46.9 months. Gastrointestinal adverse events were reported by 2,827 (42.5%) against 2,387 (35.9%).[4] That is still a comparison of two drugs, and it was constructed after the primary result was known.
The placebo arm that was imputed
Because SURPASS-CVOT had no placebo group, a prespecified indirect analysis built one. It took 2,055 of the 9,901 participants in REWIND who would have been eligible for SURPASS-CVOT, used propensity scores to adjust for differences between the populations, and multiplied the tirzepatide-versus-dulaglutide hazard ratio by the dulaglutide-versus-placebo hazard ratio from REWIND. Against that constructed comparator, tirzepatide returned a hazard ratio of 0.72 (95% CI, 0.55 to 0.94) for the three-part composite, 0.70 (95% CI, 0.51 to 0.96) for cardiovascular death or heart-failure events, and 0.61 (95% CI, 0.45 to 0.82) for death from any cause.[5]
Those are the figures most often quoted as tirzepatide’s placebo-controlled effect, and the analysis calls itself an indirect exploratory comparison. Multiplying two hazard ratios from two trials run years apart in overlapping but different populations produces an estimate whose uncertainty is wider than its confidence interval shows, because the interval prices the sampling error and not the assumption that the two populations are exchangeable.
And the arm that was a risk equation
For primary prevention the substitute is a model rather than a comparator. A post hoc analysis of SURMOUNT-1 took the 962 of 2,539 randomized participants who had prediabetes, no pre-existing cardiovascular disease and both a baseline and at least one later risk score, and calculated predicted ten-year cardiovascular risk with the Framingham equation. At week 72, tirzepatide 15 mg was associated with an absolute predicted risk reduction of 1.92% while placebo carried an increase of 1.10% (P < 0.001; model-derived hazard ratio 0.73). At week 176 the figures were a reduction of 1.31% against an increase of 3.84% (P < 0.001; hazard ratio 0.62).[6]
No cardiovascular events were counted in that analysis. Its authors state the limitation directly and name SURMOUNT-MMO as the event-based trial that would have to confirm it.[6] A predicted risk reduction is an arithmetic consequence of moving blood pressure, lipids and weight; whether those movements convert into fewer events is exactly the question under test.
What tirzepatide has actually measured
The molecule’s strongest long-term randomized data are metabolic rather than cardiovascular. The three-year analysis of SURMOUNT-1 followed 1,032 participants with both obesity and prediabetes for 176 weeks: mean weight change was −12.3%, −18.7% and −19.7% at 5, 10 and 15 mg against −1.3% on placebo, and type 2 diabetes was diagnosed in 1.3% of the tirzepatide groups against 13.3% on placebo, a hazard ratio of 0.07 (95% CI, 0.0 to 0.1).[7] How those dose arms behaved over the first 72 weeks is set out in the SURMOUNT-1 article.
The comparison that makes the gap visible is SELECT, which randomized 17,604 patients with pre-existing cardiovascular disease and a body-mass index of 27 or higher but no diabetes to semaglutide 2.4 mg or placebo. The primary cardiovascular endpoint occurred in 569 of 8,803 (6.5%) against 701 of 8,801 (8.0%), a hazard ratio of 0.80 (95% CI, 0.72 to 0.90; P < 0.001) over a mean 39.8 months, with adverse events leading to permanent discontinuation in 1,461 patients (16.6%) against 718 (8.2%).[8] That is a placebo-controlled event result in almost exactly the population SURMOUNT-MMO enrolls, and it is the template against which the tirzepatide trial will be read. It is also a reminder that in a trial of this length the discontinuation rate is a large number, which nothing yet reports for SURMOUNT-MMO.
What cannot be said, and why it matters to a buyer
Tirzepatide has not been shown to reduce cardiovascular events against placebo in anyone, with or without diabetes. It has been shown not to be worse than a drug that does, in people with diabetes. Everything beyond that is an indirect estimate or a risk model, and the sellers listed on the tirzepatide board have no cardiovascular claim available to them on this evidence. How the two molecules compare on the endpoints that have been measured is covered in the comparison article.
SURMOUNT-MMO will also be a trial of branded, FDA-approved tirzepatide escalated under supervision with free supply and scheduled visits. Compounded tirzepatide is not FDA-approved, and compounded drugs are not reviewed by the FDA for safety, efficacy or quality before they are dispensed — the distinction set out in the compounded-versus-brand article. Whatever this trial reports in 2027 or later will be a fact about the product it studied.