Eli Lilly Tirzepatide Delivers 25.5% Weight Loss vs Novo’s 23%
Novo Nordisk’s 84-week REDEFINE 4 trial showed CagriSema achieved 23.0% weight loss in adherent patients versus 25.5% for Eli Lilly’s tirzepatide, missing its non-inferiority primary endpoint. Under the treatment estimand, CagriSema delivered 20.2% weight loss compared to tirzepatide’s 23.6%.
1. REDEFINE 4 Trial Outcomes
The open-label phase 3 REDEFINE 4 trial enrolled 809 participants over 84 weeks comparing CagriSema 2.4/2.4 mg to tirzepatide 15 mg. CagriSema reached 23.0% mean weight loss in the adherent population versus 25.5% for tirzepatide, failing to meet the non-inferiority primary endpoint.
2. Tirzepatide’s Efficacy Advantage
Using the treatment regimen estimand, CagriSema produced 20.2% weight reduction at 84 weeks against tirzepatide’s 23.6%. Both drugs showed acceptable safety profiles, with CagriSema’s most common adverse events being mild to moderate gastrointestinal symptoms that diminished over time.
3. Implications for Eli Lilly
Eli Lilly’s tirzepatide, marketed as Zepbound and Mounjaro, reinforced its leading efficacy position in the obesity market. The superior trial results may bolster prescribing momentum and support stronger sales growth in 2026 and beyond.
4. Outlook on Competitor Trials
Novo Nordisk has an FDA decision on CagriSema expected by late 2026, with REDEFINE 11 readout due in the first half of 2027 and a higher-dose trial launching in the second half of 2026. Tirzepatide’s established clinical profile faces limited near-term challenge from Novo’s upcoming studies.