Le rétatrutide en 2026 : résultats de phase 3, accès anticipé et échéancier de la FDA

Recherche sur la perte de poids et le métabolisme

Retatrutide had the busiest summer of any molecule in this catalogue. Three phase 3 trials reported between May and July 2026, Lilly opened an early access program in August, and the company has now said when it intends to file for approval. This is a plain summary of what was actually announced, with the figures as Lilly published them, and what it does and does not change for research supply in Canada.

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Findings

• TRIUMPH-1 (May 2026): 28.3% average weight loss at 80 weeks on the 12 mg dose, 30.3% at 104 weeks in the extension group.
• TRIUMPH-2 and TRIUMPH-3 (July 2026): 20.8% in adults with type 2 diabetes and 22.6% in adults with severe obesity and cardiovascular disease, both at 80 weeks.
• An early access program opened on 3 August 2026 for a narrow group of patients, through their physicians. It is not an approval.
• Lilly plans to file its Biologics License Application with the FDA in the first quarter of 2027.
• A head-to-head trial against tirzepatide (TRIUMPH-5) is due to complete its primary phase in November 2026.

TRIUMPH-1: the obesity trial, 21 May 2026

The first registrational readout came on 21 May 2026. TRIUMPH-1 randomised 2,339 adults with obesity or overweight to retatrutide 4 mg, 9 mg or 12 mg, or placebo, for 80 weeks. Average weight change at 80 weeks, as reported by Lilly:

• 4 mg: 19.0% (47.2 lb)
• 9 mg: 25.9% (64.4 lb)
• 12 mg: 28.3% (70.3 lb)
• Placebo: 2.2% (5.5 lb)

At 80 weeks, 45.3% of participants on 12 mg had lost at least 30% of their body weight. A pre-specified extension followed 532 participants with a baseline BMI of 35 or higher for a further 24 weeks. Those who stayed on 12 mg through 104 weeks averaged 30.3% (85.0 lb). Discontinuation because of adverse events ran 4.1%, 6.9% and 11.3% on the three doses, against 4.9% on placebo.

TRIUMPH-2 and TRIUMPH-3: diabetes and cardiovascular disease, 23 July 2026

Two more trials reported together in July. Both ran 80 weeks.

TRIUMPH-2 enrolled 1,152 adults with type 2 diabetes and obesity or overweight. Weight change averaged 12.7% (4 mg), 19.1% (9 mg) and 20.8% (12 mg) against 4.0% on placebo. HbA1c fell by up to 1.6 percentage points from a 7.7% baseline, against 0.2 points on placebo. Weight loss in people with type 2 diabetes typically runs below what non-diabetic cohorts show, which is the right lens for these numbers.

TRIUMPH-3 enrolled 1,949 adults with severe obesity (BMI 35 or higher) and established cardiovascular disease. Weight change averaged 21.6% (9 mg) and 22.6% (12 mg) against 3.2% on placebo. On the 12 mg dose Lilly reported triglycerides down 37.0%, non-HDL cholesterol down 16.5%, systolic blood pressure down 9.3 mmHg, waist circumference down 19.0 cm and high-sensitivity C-reactive protein down 51.2%. Over the 80 weeks there were 44 major cardiovascular events in the pooled 9 mg and 12 mg groups against 52 on placebo, a hazard ratio of 0.82 with a confidence interval of 0.55 to 1.22, which means the study was not sized to prove a cardiovascular benefit. That question belongs to the separate TRIUMPH-Outcomes trial. Discontinuation for adverse events was 9.8% and 13.5% on the two doses against 4.8% on placebo.

Early access is not approval

On 3 August 2026 Lilly confirmed that a defined group of patients can apply for retatrutide ahead of approval. The criteria are narrow: adults 18 and over with severe obesity and serious related health problems, whose condition has not responded to the highest tolerated dose of an approved obesity medication, and who cannot enrol in a clinical trial. The patient’s clinician submits the request, and each case is reviewed by Lilly, the FDA and an institutional review board. It is a compassionate-use route for a small number of people, not a soft launch.

The timeline from here

• November 2026: TRIUMPH-5 (NCT06662383), the first head-to-head trial of retatrutide against tirzepatide, reaches its estimated primary completion date. That is the trial that will settle the comparison people currently argue about from separate studies.
• First quarter of 2027: Lilly plans to submit its Biologics License Application to the FDA. The company said it needed more time to gather manufacturing and quality-control data before filing.
• 2028, on a standard review clock: the earliest a US decision could realistically land. Health Canada runs its own process on its own schedule.

What this changes for research supply in Canada

Nothing about the regulatory status of the research material, and a great deal about the level of interest in it. Retatrutide supplied for laboratory research is not the pharmaceutical product in these trials and does not become one when that product is approved. What the trials do is settle the question of whether the triple-agonist mechanism is worth studying: three phase 3 readouts say it is, which is why retatrutide is the most visited product page on this site.

The practical advice does not change either. Buy from a supplier who publishes a certificate of analysis for the compound, check the purity figure and the identity method on it, and keep the vial cold and dry until reconstitution with eau bactériostatique. Our retatrutide vs tirzepatide comparison covers the receptor difference, and the trial record covers the phase 2 and diabetes data that preceded this summer’s results.

Questions fréquentes

Is retatrutide approved anywhere?

No. As of September 2026 it has no marketing authorisation in the United States, Canada, the United Kingdom or the European Union. Lilly plans to file with the FDA in the first quarter of 2027.

How much weight did people lose in the phase 3 trials?

In TRIUMPH-1, an average of 28.3% at 80 weeks on the 12 mg dose, and 30.3% at 104 weeks in the extension group with a baseline BMI of 35 or higher. In adults with type 2 diabetes the 12 mg average was 20.8%, and in adults with severe obesity and cardiovascular disease it was 22.6%.

Can Canadians get retatrutide through Lilly’s early access program?

The program Lilly confirmed in August 2026 runs through US physicians and the FDA’s expanded access framework, with strict clinical criteria. It is not a general access route.

Has retatrutide been compared with tirzepatide directly?

Not yet in published results. TRIUMPH-5 is the head-to-head trial, with an estimated primary completion date of November 2026.

Sources: Eli Lilly and Company, “Lilly’s triple agonist, retatrutide, delivered powerful weight loss in pivotal Phase 3 obesity trial” (TRIUMPH-1), press release, 21 May 2026, via PR Newswire. Eli Lilly and Company, “Lilly’s triple agonist, retatrutide, successful in two additional Phase 3 obesity trials” (TRIUMPH-2 and TRIUMPH-3), press release, 23 July 2026, via PR Newswire. STAT News, “Eli Lilly to offer retatrutide access given earlier to just one patient”, 3 August 2026, statnews.com. BioPharma Dive, “Lilly, with new data, to seek FDA approval of obesity drug retatrutide”, 23 July 2026, biopharmadive.com. ClinicalTrials.gov, NCT06662383 (TRIUMPH-5).

Références

Le rétatrutide a été évalué dans des essais humains randomisés contrôlés par placebo jusqu'à la phase 3.

1. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 TrialJastreboff AM et al. · N Engl J Med 2023 · PMID 37366315Essai d'obésité de phase 2 randomisé, à double insu, contrôlé par placebo, 48 semaines.
2. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USARosenstock J et al. · Lancet 2023 · PMID 37385280Essai de phase 2 randomisé, à double insu, contrôlé par placebo et comparateur actif; 281 participants avec diabète de type 2.
3. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trialSanyal AJ et al. · Nat Med 2024 · PMID 38858523Sous-étude de phase 2a randomisée; 98 participants avec stéatose hépatique associée à une dysfonction métabolique.
4. Efficacy and safety of retatrutide, a GIP, GLP-1, and glucagon receptor agonist, in people with type 2 diabetes and inadequate glycaemic control with diet and exercise (TRANSCEND-T2D-1): a double-blind, randomised, phase 3 trialBajaj HS et al. · Lancet 2026 · PMID 42250575Essai de phase 3 randomisé à double insu dans le diabète de type 2 (TRANSCEND-T2D-1).

Les liens ouvrent la fiche de l'étude sur PubMed afin que la source puisse être vérifiée directement. Citer une étude ne signifie pas que ses résultats s'appliquent à un autre usage, produit ou mode d'administration. Usage laboratoire uniquement.