retatrutide · 80 weeks
TRIUMPH-1
At 80 weeks, weight changed by −17.6%, −23.7% and −25.0% with retatrutide 4, 9 and 12 mg, compared with −3.9% on placebo, using the treatment-regimen estimand (intention to treat).
Randomized controlled trial
TRIUMPH-2: retatrutide for obesity with type 2 diabetes
At 80 weeks, weight changed by −11.9%, −16.8% and −18.8% with retatrutide 4, 9 and 12 mg, compared with −5.1% on placebo, using the treatment-regimen estimand; the differences were −6.9 (95% CI, −8.7 to −5.1), −11.8 (95% CI, −13.7 to −9.8) and −13.8 percentage points (95% CI, −15.8 to −11.8), all p < 0.0001. 84% of participants completed treatment.
Bellido V et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2): a double-blind, parallel-group, randomised, placebo-controlled, phase 3 trial. The Lancet, 2026. DOI: 10.1016/S0140-6736(26)01861-1
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- Alex Gonzalez
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Key facts
- Drug
- retatrutide
- Design
- Randomized controlled trial
- Participants
- 1,152
- Duration
- 80 weeks
- Funding
- Eli Lilly
- Registry
- NCT05929079
- Population
- 1,152 adults with type 2 diabetes (HbA1c of 6.5 to 10.5%) and a BMI of 27 or more, managed with diet and exercise alone or with up to three oral diabetes drugs, at 92 sites in eight countries; 48% women, mean age 55.1 years, mean BMI 38.2 and mean HbA1c 7.71%. 92% were taking an oral diabetes drug.
- Primary outcome
- Percentage change in weight from baseline to week 80 with retatrutide 9 and 12 mg once weekly versus placebo; the comparison of the 4 mg dose with placebo was a key secondary objective.
What it found
At 80 weeks, weight changed by −11.9%, −16.8% and −18.8% with retatrutide 4, 9 and 12 mg, compared with −5.1% on placebo, using the treatment-regimen estimand; the differences were −6.9 (95% CI, −8.7 to −5.1), −11.8 (95% CI, −13.7 to −9.8) and −13.8 percentage points (95% CI, −15.8 to −11.8), all p < 0.0001. 84% of participants completed treatment. The most common adverse effects were digestive: diarrhea affected 27%, 34% and 34% with the three doses, compared with 13% on placebo, and nausea 14%, 21% and 28%, compared with 8%; hypotension (1%, 5% and 6%, compared with less than 1%) and dysesthesia (4%, 6% and 7%, compared with 1%) were also more common with retatrutide. 4%, 12% and 8% stopped treatment because of adverse effects or death with 4, 9 and 12 mg, compared with 5% on placebo; there were six deaths on retatrutide and one on placebo, none related to treatment according to the investigator.
Limitations
Funded by Eli Lilly, which is developing retatrutide. The paper’s abstract says blood sugar control improved but does not give the HbA1c figure. It was compared with placebo, not with other treatments. Retatrutide is an investigational drug, not approved in any country.
What it means for you
In people with type 2 diabetes and obesity or overweight, weekly retatrutide 12 mg reduced weight by an average of 18.8% over 80 weeks, compared with 5.1% on placebo, a smaller loss than in TRIUMPH-1 in people without diabetes. Retatrutide is not yet approved in any country. These data help show where research is heading, but they are not a basis for choosing a treatment or a dose today.
Further reading
Sources
The original paper and the records consulted for this summary, with the date they were accessed.
- The Lancet.Bellido V, et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2): a double-blind, parallel-group, randomised, placebo-controlled, phase 3 trial. Lancet. Published online September 29, 2026.accessed .
- National Library of Medicine (PubMed).PubMed record PMID 42810372 (abstract).accessed .
- ClinicalTrials.gov (National Library of Medicine).ClinicalTrials.gov record NCT05929079 (TRIUMPH-2: registration and eligibility).accessed .