Full Breakdown
Eli Lilly Reports Record Weight-Loss Results for New Obesity Drugs
By Drooid · · How we work
Core Trial Results
On September 30, Eli Lilly announced that its experimental combination therapy EloraTZP (eloralintide + tirzepatide) produced an average 23.3 % body-weight loss (? 54 lb) after 48 weeks in a mid-stage trial of 367 adults with obesity or overweight and type 2 diabetes. The same regimen lowered A1C by up to 2.9 %. A high-dose tirzepatide (Zepbound) arm lost 14.8 % weight (? 34 lb) and reduced A1C by 2.4 %.
In the Phase 3 TRIUMPH-2 study, retatrutide – a triple-agonist targeting GLP-1, GIP and glucagon – achieved 20.8 % mean weight loss (? 49.6 lb) at the 12 mg dose over 80 weeks, with A1C falling by 1.6 % and up to 40 % of participants reaching an A1C below 5.7 %. More than half of the 12 mg group no longer met the BMI criterion for obesity. Both programs met primary efficacy endpoints, setting new benchmarks for patients with type 2 diabetes.
Background & Context
Current obesity treatments such as semaglutide (Wegovy) and tirzepatide (Zepbound) act on the GLP-1 receptor, with tirzepatide also engaging GIP. Lilly’s combination adds an amylin agonist (eloralintide) to hit a third satiety pathway, while retatrutide simultaneously activates GLP-1, GIP and glucagon receptors. The strategy deepens appetite suppression and improves metabolic control, positioning Lilly against Novo Nordisk, which is developing its own amylin-GLP-1 combo (CagriSema).
Data & Statistics
| Metric | EloraTZP (48 wks) | Tirzepatide alone | Retatrutide (80 wks, 12 mg) |
|---|---|---|---|
| Mean weight loss | 23.3 % (? 54 lb) | 14.8 % (? 34 lb) | 20.8 % (? 49.6 lb) |
| A1C reduction | up to 2.9 % | up to 2.4 % | up to 1.6 % |
| Discontinuation (adverse events) | 10.8 %–27 % | 2.9 % | 7.7 % (12 mg) |
| BMI < 30 achieved | – | – | > 50 % (12 mg) |
| Cardiovascular risk-factor changes* | – | – | Triglycerides – 39.5 %, non-HDL cholesterol – 19.6 %, systolic BP – 10.8 mmHg |
*Data shown for retatrutide only.
Official Statements & Responses
Lilly will refine dose-escalation schedules in upcoming Phase 3 trials slated for the fourth quarter of 2026 and will develop a single-injection co-formulation.
Conflicting Reports & Gaps
The reported discontinuation rate for EloraTZP varies: Reuters cited 8 %–27 %, while CNBC and Biospace reported 10.8 %–27 %. Both sources agree rates are higher than for tirzepatide alone, but the exact lower bound differs. Long-term safety data, especially regarding gallstone risk and micronutrient deficiencies associated with rapid weight loss, remain unpublished.
What’s Next
Lilly plans to launch Phase 3 trials of EloraTZP by the end of 2026, testing an optimized dosing schedule and a co-formulation that delivers both agents in a single injection. A Biologics License Application for retatrutide is targeted for the first quarter of 2027, with additional analyses of its effects on obstructive sleep apnea and cardiovascular risk factors to be presented at future medical meetings.
