Eli Lilly's push beyond tirzepatide (Mounjaro/Zepbound) gained another contender after an experimental amylin combination drove substantially greater weight loss than the blockbuster obesity drug alone in a Phase IIb trial.
The company reported that EloraTZP, combining the selective amylin receptor agonist eloralintide with the GIP/GLP-1 receptor agonist tirzepatide, produced average weight loss of up to 23.3% at 48 weeks in adults with obesity or overweight and type 2 diabetes, compared with 14.8% for tirzepatide 15 mg alone. The highest-dose combination also reduced A1C by 2.9%, versus 2.4% with tirzepatide.
The Phase IIb trial (NCT06603571) was a 48-week, double-blind, placebo-controlled study enrolling 367 adults. All EloraTZP dose combinations met the primary endpoint of percent change in body weight versus placebo, as well as secondary A1C endpoints.
EloraTZP adds eloralintide's selective amylin receptor agonism to tirzepatide's dual GIP and GLP-1 receptor activity, giving Lilly a three-pathway combination as it explores several approaches to pushing weight loss beyond its existing incretin franchise.
Gastrointestinal adverse events were the most common and were generally mild or moderate, but occurred more frequently in the combination groups. Treatment discontinuation due to adverse events ranged from 10.8% to 27.0% with EloraTZP, compared with 2.9% for tirzepatide alone.