When will maintenance data be available?

TRIUMPH-6 has a primary completion date of April 2028, with publication following after that.

Is maintenance data available for any incretin?

Cessation data exists (the STEP-1 extension is the best known), but purpose-built maintenance-dosing trials are still reading out across the class.

Why do maintenance trials take longer than efficacy trials?

They need a reduction phase, then randomisation to a maintenance strategy, then long follow-up. Three sequential stages instead of one.

TRIUMPH-6: The Maintenance Trial, and Its Timeline

The short answer

TRIUMPH-6 (NCT06859268) is a Phase 3 trial of retatrutide in the maintenance of weight reduction, enrolling 643 participants. It began in March 2025 and has a primary completion date of April 2028. The field's most important open question therefore has no answer for several years.

Key facts

Registration: NCT06859268
Acronym: TRIUMPH-6
Focus: Maintenance of weight reduction
Phase: 3
Enrolment: 643 participants
Started: 5 March 2025
Primary completion: April 2028
Status: Active, not recruiting

The question it addresses

Every headline figure in this field describes weight while treatment continues. What happens afterwards is measured far less often, and where it has been measured the answer is uncomfortable: the STEP-1 extension found roughly two-thirds of the loss returning within a year of stopping semaglutide. Maintenance dosing asks whether a reduced dose can hold the result without the full treatment burden.

Why the completion date matters

TRIUMPH-6 has a primary completion date of April 2028. That needs saying clearly, because commentary (including some of the earlier articles in this library) tends to describe maintenance data as imminent, or as the thing the field is currently waiting on. It is neither. It is several years out, and until then every claim about durability rests on extrapolation from other compounds.

Research material referenced

Retatrutide 10mg, third-party HPLC tested

Buy Retatrutide · £49.99

Why maintenance trials take so long

The design requires participants to reach a reduction plateau first, then be randomised to a maintenance strategy, then be followed long enough for divergence to appear. That is three sequential phases rather than one. A 12-month endpoint measured after a 12-month run-in is a two-year trial before analysis, which is why maintenance evidence lags efficacy evidence across the whole class by years.

What this means for reading efficacy figures

A peak reduction figure describes a maintained state, not an achieved outcome. Retatrutide's 28.3% at 80 weeks is the reduction present while treatment continued at 12 mg. Whether any of it persists at a lower dose, or without treatment, is exactly what TRIUMPH-6 exists to find out and will not report until 2028. Reading peak figures as durable results is the single most common error in coverage of this field.

Scale and status

The trial enrolled 643 participants and began on 5 March 2025. It is listed as active but no longer recruiting. Retatrutide remains investigational in every jurisdiction throughout.

Frequently asked questions

When will maintenance data be available?: TRIUMPH-6 has a primary completion date of April 2028, with publication following after that.
Is maintenance data available for any incretin?: Cessation data exists (the STEP-1 extension is the best known), but purpose-built maintenance-dosing trials are still reading out across the class.
Why do maintenance trials take longer than efficacy trials?: They need a reduction phase, then randomisation to a maintenance strategy, then long follow-up. Three sequential stages instead of one.

Extended research context

The Research & Regulatory News deep dive

Deep dive: why 2026 was the year the incretin field split in two

For a decade every meaningful GLP-1 medicine was a peptide, and every one of them was injected. 2026 broke that pattern in both directions at once. In August the MHRA authorised orforglipron, a small molecule with no peptide bonds that works as an ordinary daily tablet. Three months earlier, retatrutide's TRIUMPH-1 reported a 28.3% mean weight reduction. That is the largest figure yet from a single molecule, and achievable only with a peptide capable of engaging three receptors at once. The field is not converging on one answer. It is separating into a convenience track and a magnitude track, and those tracks have different chemistry.

Deep dive: what a marketing authorisation actually means

An authorisation is granted to a specific product, in a specific formulation, for a specific indication, by a specific regulator. It is not a statement about a compound class and it does not transfer. Orforglipron being licensed in the UK tells you nothing about the legal or regulatory status of any other incretin, and nothing at all about compounds that remain investigational. Authorisation is also separate from funding: a licensed medicine is not automatically available on the NHS, which requires a further NICE appraisal.

Deep dive: reading trial results without being misled

Headline percentages are the least transferable part of a trial. A figure is only meaningful alongside its population, its duration, its comparator and its dropout rate. TRIUMPH-1's 28.3% came from an 80-week study in a relatively uncomplicated obesity population; TRIUMPH-3's 22.6% came from adults with severe obesity and established cardiovascular disease, and the gap between those two numbers is mostly population, not potency. Discontinuation rates deserve the same attention as efficacy: 11.3% of the TRIUMPH-1 12 mg arm stopped due to adverse events against 4.9% on placebo, and that figure is routinely dropped from summaries.

Research applications

▸Tracking regulatory status of investigational incretin compounds
▸Understanding the difference between authorisation, NICE appraisal and NHS availability
▸Comparing peptide and non-peptide receptor agonist pharmacology
▸Interpreting Phase 3 topline releases before peer-reviewed publication
▸Verifying trial identity against ClinicalTrials.gov registrations

Handling checklist

✓Check the compound named in a trial registration matches the compound being discussed
✓Confirm the NCT identifier resolves to the acronym being cited
✓Read topline press releases as preliminary until peer-reviewed publication
✓Separate the trial population from the headline percentage before comparing studies
✓Treat authorisation in one jurisdiction as saying nothing about status in another

Common research-handling mistakes

Learnt from thousands of researcher orders across our UK labs.

✗ Treating a positive Phase 3 as approval

Fix: Filing begins a review that commonly takes a year or more and can end in a request for more data.

✗ Comparing weight-reduction percentages across different trials

Fix: Population, duration and comparator differ; the numbers are not interchangeable.

✗ Assuming one incretin's approval legitimises another compound

Fix: Authorisations are product-specific and do not transfer between compounds.

✗ Citing a TRIUMPH number without checking the NCT identifier

Fix: Verify against ClinicalTrials.gov, as the numbering has been widely misreported.

✗ Reading research material as an alternative to a licensed medicine

Fix: Research material is supplied for laboratory use only and is not a substitute for anything prescribed.

Continue researching

Peer-reviewed guides, comparators and matched reference materials.

Primary sources & clinical trials

Peer-reviewed research and registered trials from PubMed, ClinicalTrials.gov, PubChem, FDA and NIH. All links open in a new tab and point to the primary source, so every claim can be verified at origin.

UKP

Written and reviewed by

The UK Peptides Editorial Team · Research library, UK Peptides

The editorial team is responsible for supplier selection, batch release decisions and the content published in this research library. Every article here is sourced to primary literature and every product page to a signed third-party certificate. Corrections are made in place and the review date updated.

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TRIUMPH-6: Maintenance of Weight Reduction