Lilly's EloraTZP (eloralintide + tirzepatide) outperforms tirzepatide 15 mg in Phase 2b obesity and T2D trial

Study design

The Phase 2b trial randomized 367 adults with overweight or obesity and type 2 diabetes in the U.S. and Argentina to placebo, eloralintide, tirzepatide or combinations (EloraTZP) for 48 weeks. The primary endpoint was percent change in body weight from an average baseline of 232.4 lbs; a key secondary endpoint was change in A1C from an average baseline of 8.1%.

Efficacy results

All EloraTZP dose combinations met primary and secondary endpoints. The highest-dose combination (eloralintide 9 mg + tirzepatide 15 mg) produced a mean 23.3% weight loss (54.1 lbs) and a 2.9% A1C reduction at 48 weeks. By comparison, tirzepatide 15 mg produced a mean 14.8% weight loss (34.4 lbs) and a 2.4% A1C reduction. Eloralintide alone reduced weight by up to 12.3% (28.6 lbs) and A1C by up to 1.4% versus placebo (−3.0% weight, −0.3% A1C).

Safety and tolerability

The most common adverse events were gastrointestinal and generally mild to moderate, occurring primarily during dose escalation and more frequently in combination arms than with either agent alone. Treatment discontinuation due to adverse events ranged from 10.8% to 27.0% for EloraTZP arms, 0%–10.8% for eloralintide arms, 2.9% for tirzepatide, and 16.7% for placebo.

Next steps

Results were presented at EASD. Lilly plans to initiate Phase 3 studies of an EloraTZP co‑formulation using an optimized escalation schedule by the end of 2026 (Q4 2026).