The TRIUMPH program is Eli Lilly's multi-trial Phase 3 investigation of retatrutide across obesity, type 2 diabetes, cardiovascular disease, and metabolic liver disease. Results published through mid-2026 consistently demonstrate weight loss outcomes that exceed the established GLP-1 and dual agonist benchmarks — with a safety and tolerability profile broadly consistent with the incretin class.
Key completed trials and outcomes
TRIUMPH-1 (obesity, 24mg): 26.5% mean weight loss at 96 weeks, 42% of participants achieved ≥25% weight loss. TRIUMPH-2 (type 2 diabetes): 17.5% mean weight loss with significant HbA1c reduction. TRIUMPH-3 (obesity + cardiovascular risk): 24.1% mean weight loss with 22% reduction in major adverse cardiovascular events. TRIUMPH-4 (obesity + knee osteoarthritis): 28.7% mean weight loss with substantial improvement in knee pain scores.
Safety and tolerability profile
The most common adverse events are gastrointestinal: nausea (54%), vomiting (28%), and diarrhoea (22%) — consistent with the incretin class and most pronounced during dose escalation. A dysesthesia signal (tingling and numbness, typically in the hands and feet) was identified in Phase 2 and is under Phase 3 monitoring. Most dysesthesia cases are transient and resolve without dose adjustment. Serious adverse events were rare and comparable to placebo-adjusted rates for the patient populations studied.
The MASLD/MASH liver disease data
The most striking retatrutide data point outside weight loss is the Phase 2a liver disease trial: 86% mean liver fat reduction in patients with metabolic dysfunction-associated steatotic liver disease (MASLD). This is largely attributable to the glucagon receptor mechanism — no other GLP-1 class compound has produced liver fat reduction data at this level. Phase 3 liver outcomes data is expected in 2026.
Regulatory timeline
Lilly has indicated FDA submission is anticipated following completion of the full TRIUMPH program readouts, with a target submission window of 2026–2027. If approved on this timeline, retatrutide would represent the first new obesity drug mechanism since the incretin class itself — with clinical outcomes in a new range above what the existing approved compounds can achieve.