- Design
- phase 3, double-blind, parallel-group, randomised, placebo-controlled, 80 weeks
- Population
- 1,152 adults with obesity and type 2 diabetes, mean BMI 38.2 kg/m2, mean HbA1c 7.71%
- Primary outcome
- percentage change in bodyweight from baseline to week 80
- Effect
- -18.8% on 12 mg vs -5.1% on placebo; difference -13.8% (95% CI -15.8 to -11.8)
TRIUMPH-2 randomised 1,152 adults with a BMI of 27 kg/m2 or above and type 2 diabetes, mean HbA1c 7.71%, to weekly subcutaneous retatrutide at 4, 9 or 12 mg or to placebo for 80 weeks, across 92 centres in eight countries. Retatrutide agonises three receptors - GIP, GLP-1 and glucagon. Ninety-two per cent of participants were already on an oral glucose-lowering drug.
Weight fell 11.9% on 4 mg, 16.8% on 9 mg and 18.8% on 12 mg, against 5.1% on placebo. The treatment difference at 12 mg was -13.8% (95% CI -15.8 to -11.8). Weight loss of this size in people with type 2 diabetes has historically been harder to achieve than in people without it.
The tolerability column deserves equal attention. Diarrhoea affected about a third on the higher doses against 13% on placebo, and nausea 28% at 12 mg against 8%. Hypotension (6% at 12 mg versus under 1%) and dysaesthesia (7% versus 1%) are less familiar from this class and worth knowing about. Discontinuation for adverse events or death was highest not at the top dose but at 9 mg, 12% against 5% on placebo, which is an odd pattern rather than a reassuring one. The drug is not approved anywhere, and the trial reports weight and glycaemia, not events.
- Retatrutide adds glucagon receptor agonism to the GIP and GLP-1 actions of tirzepatide.
- Ask about postural symptoms if a patient is on any triple agonist in a trial - hypotension was commoner than placebo.
- Dysaesthesia was reported in 7% at the top dose; it is not a familiar effect of this class.
- No cardiovascular or renal outcome data are available from this trial.
- Not licensed in India or elsewhere; nothing to prescribe or plan around yet.
Why it matters
The ceiling on achievable weight loss in type 2 diabetes keeps moving, and the conversation is shifting from whether to treat obesity pharmacologically to which agent and at what tolerability cost.
Don't overread it
Weight and HbA1c are intermediate endpoints - this trial says nothing about cardiovascular or renal outcomes.
The statistics, in plain English
The confidence intervals around the weight differences are narrow and nowhere near zero, so the size of the effect is well established for this population over 80 weeks. What is not established is anything about outcomes: weight and HbA1c are intermediate measures, and a drug that moves them does not automatically prevent infarcts, kidney disease or death. The higher discontinuation rate at 9 mg than at 12 mg is most likely chance in groups of under 300, but it is a reason not to read the safety data as a clean dose gradient.
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