Journal club: SURMOUNT-1, read without the press release

Journal club: SURMOUNT-1, read without the press release Writing it up because I had to work it out twice and would rather nobody else did.

Session topic: STEP 1 (N Engl J Med, 2021). Please read it before posting; the discussion is much better when everyone has.

The question I would like us to start with is what the trial set out to estimate, rather than what it found. Once that is on the table we can talk about whether the design could have answered it, and only then about the numbers.

Specific things I would like covered: the population and how far it generalises, how discontinuation was handled, whether the comparator was a fair one, and what the absolute rather than relative effect looks like.

I will summarise at the end and the summary will feed the relevant digest page.

Session format: read the paper before posting. The discussion is much better when everyone has. Start with the estimand and population, then methods, then results, then limitations. That order makes critique coherent.

TRIUMPH (ongoing): Retatrutide phase 3. No results yet. Nothing should be attributed to it because it has not finished. When it does, this discussion will return to it.

Picking up the opening post: that is the part I would want checked first.

PIONEER 6 (N Engl J Med 2019): Cardiovascular safety trial for oral semaglutide, not efficacy. Non-inferiority for safety was met. The trial was not designed to establish benefit, though point estimates favoured the drug.

SURMOUNT-OSA (N Engl J Med 2024): Tirzepatide in obstructive sleep apnoea, using an objective physiological endpoint. Notable because soft endpoints are avoided. Two parallel trials addressed the confounder directly.

For anyone arriving from a search: the marked solution above is the direct answer, and the replies underneath it add the caveats that make it safe to use.

I read post #5 twice before replying, because I had assumed the opposite.

SURMOUNT-1 (N Engl J Med 2022): Tirzepatide obesity trial. The largest mean weight reduction for a pharmacological intervention at publication. Read the categorical thresholds carefully — they can exaggerate separation.

This follows post #5 rather than contradicting it.

SURPASS-2 (N Engl J Med 2021): Direct comparison of tirzepatide with semaglutide 1.0 mg. The 1.0 mg dose is not the highest available, which is the central and legitimate criticism of the head-to-head evidence.

SELECT (N Engl J Med 2023): Semaglutide cardiovascular outcomes without diabetes. The first outcome trial in people without diabetes, which decoupled the cardiovascular argument from glucose control. Read the absolute numbers, not just the relative reduction.

post #9 answers the question as asked. The question underneath it is different.

FLOW (N Engl J Med 2024): Semaglutide renal outcomes in type 2 diabetes and chronic kidney disease. Stopped early for efficacy. Component-by-component analysis is essential because the components differ in how patient-important they are.

post #10 is right about the mechanism and I think understates the practical bit.

SOUL (N Engl J Med 2025): Oral semaglutide cardiovascular outcomes. Extends the cardiovascular evidence to the oral formulation. Note that oral bioavailability is lower and more variable than injectable.

Worth separating two things that post #8 runs together.

Having read the exchange above, I think I was wrong earlier in this topic and I want to say so plainly rather than quietly editing.

The correction was fair and I had been repeating something I had not checked carefully enough.

Critical appraisal template: (1) What did the trial set out to estimate? (2) Could the design answer that question? (3) Was the population sufficiently similar to your population to apply the results? (4) What was the absolute effect, not just the relative one? (5) What are the two strongest criticisms available?

STEP 1 (N Engl J Med 2021): The pivotal obesity trial for semaglutide and the reference point for most subsequent comparison. Mean weight reduction was substantially larger than anything previously achieved pharmacologically.