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What does TRIUMPH-1 report at the 8 mg dose level?

Asked 23 Oct 2024Modified 18 months agoViewed 7.1k times
4

For reference: TRIUMPH-1 · 8 mg.

I want to understand what this actually establishes, as opposed to what it is being used to imply.

My concern is that I am being invited to draw a conclusion the data does not support.

What is the correct interpretation, and what is the common misreading?

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askedfiadh_cronin58k5823 Oct 2024

5 Answers

Accepted answer first, then by votes
6

Accepted answer

Read the 8 mg row, not the pooled one. A programme that randomised more than one dose level reports each arm separately, and the figure that circulates afterwards is usually either the top-dose arm or an average across arms nobody was randomised to. If TRIUMPH-1 ran a 8 mg arm, that row carries its own sample size and its own confidence interval, and both are narrower than the trial-level ones by roughly the square root of however many arms there were. Take the primary publication rather than the press release: one reports by arm, the other reports whichever number is largest. A dose level inside a trial is a protocol decision made under supervision, not a recommendation, and nothing here is medical advice.

Answer first: read the primary endpoint, the comparator and the population before you read the effect size. Almost every argument on this site about a trial is really an argument about one of those three.

Intention-to-treat and per-protocol analyses answer different questions. ITT asks what happens if you offer the treatment; per-protocol asks what happens if it is taken as directed. The gap between the two is a measure of how tolerable the protocol was.

Relative to absolute, worked

QuantityValueDerivation
Control-arm event rate8.0 %From the trial table, not the abstract
Hazard ratio0.80Reported
Treated event rate6.4 %8.0 × 0.80
Absolute risk reduction1.6 pp8.0 − 6.4
Number needed to treat631 ÷ 0.016
Relative risk reduction20 %1 − 0.80

The last two rows describe the same finding. Only one of them is used in headlines.

Duration decides what can be seen. A 68-week trial can measure weight and glycaemia; it cannot measure anything whose event rate is one per cent per year without enrolling tens of thousands.

The cardiovascular outcome programme in this class runs to several large randomised trials — LEADER for liraglutide, SUSTAIN-6 and SELECT for semaglutide, REWIND for dulaglutide — and they are the reason the class is discussed as more than a weight intervention.

Read the protocol and the statistical analysis plan if the result matters to you. Both are usually published alongside.

edited 14 Dec 2024 by Dr_Jonas_Halvorsen — added a caveat about sampling

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DH
answered · acceptedDr_Jonas_Halvorsen28k377 Dec 2024
2Same experience here, different supplier. – plate_count_9k 8 months ago
The number needed to treat is the framing that finally made this concrete for me. – p_mkhize 6 months ago
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100

The honest answer here is that the published evidence supports part of the claim and is silent on the rest, and it is worth being precise about which part is which.

Confidence intervals matter more than point estimates when two trials disagree. Two studies reporting fifteen and twenty per cent whose intervals overlap heavily have not disagreed about anything.

Mechanically, a composite endpoint is only as informative as its least serious component. Where a cardiovascular composite combines death, infarction and stroke, ask which component moved, because they are not interchangeable outcomes.

Registry entries at ClinicalTrials.gov carry the pre-specified primary endpoint with a timestamp, which is the cheapest available check on whether an endpoint was changed after the data were seen.

Quote the interval alongside the estimate and half the disagreements on this site would not start.

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SK
answereds_kalniete57k3818 Dec 2024
7Good answer, but the confidence interval in the cited trial is wider than implied. – Dr_Bram_Verhoeven 5 months ago
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49

The short version: the effect is real, the magnitude depends on the population, and the population is usually the part that gets dropped when a result is quoted second-hand.

Open-label extensions are not the same evidence as the randomised phase. Once everyone knows what they are taking, the reported outcomes acquire a bias that no analysis fully removes.

More usefully, placebo arms in this class are not nothing. Lifestyle-intervention placebo arms in the major obesity trials commonly lose two to three per cent of body weight, so an active-arm figure quoted without its comparator overstates the drug effect by roughly that much.

Meta-analyses in this area are dominated by whichever trial contributed the most participants, so read the forest plot rather than the summary estimate.

The caveat is that trial evidence is about licensed product administered under supervision. None of it transfers automatically to research-grade material of unverified content.

If a claim cannot be traced to a named trial with a named endpoint, treat it as a claim rather than as evidence.

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DH
answeredDr_Jonas_Halvorsen28k3726 Nov 2024
5Which population was that figure from? It moves a lot between the trials. – loss_on_drying 9 months ago
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40

This is answerable from the published record, but only if you take the placebo arm seriously rather than reading the active arm alone.

Trial populations are selected. Exclusion criteria in this class routinely remove people with significant renal impairment, prior pancreatitis and unstable psychiatric illness, which is exactly the population the results are then quoted for.

Where a result is quoted from a conference abstract rather than a peer-reviewed publication, the numbers routinely move between the two. It is worth checking which one you are reading.

The short version: check the endpoint, check the comparator, check who was excluded, then look at the number.

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DF
answeredDr_Nadia_Farsi104k24715 Nov 2024
32

Look at the discontinuation rate alongside the efficacy figure. A large effect in the two thirds who stayed is a different result from a large effect in everyone.

Non-inferiority and superiority designs are not interchangeable. A non-inferiority result says the new agent is not meaningfully worse against a pre-specified margin — it does not say it is as good, and it certainly does not say it is better.

SELECT reported a hazard ratio of 0.80 (95% CI 0.72–0.90) for the primary composite major adverse cardiovascular event endpoint with semaglutide 2.4 mg in overweight or obese adults with established cardiovascular disease and without diabetes[1].

When two sources disagree, the answer is almost always in the methods section of the one you have not read.

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DF
answeredDr_Nadia_Farsi104k2471 Feb 2025
2This matches what I was told by a clinician, for whatever that is worth. – thermal_mass 4 days ago
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Your answer

Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.

Not medical advice. Research-use-only compounds are not approved for human use.