Eli Lilly presented new Phase 2b data on September 30, 2026 at the 62nd Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan, Italy, showing that a combination of two of its investigational and approved peptide drugs, eloralintide and tirzepatide, produced greater weight loss and blood sugar improvement than tirzepatide alone in adults with obesity or overweight and type 2 diabetes.
The Trial
The study (NCT06603571) was a 48-week, double-blind, placebo-controlled Phase 2b trial enrolling 367 adults in the United States and Argentina. Participants were randomized to one of several dose combinations of eloralintide (an amylin receptor agonist Lilly has been studying on its own) and tirzepatide (the dual GLP-1/GIP receptor agonist already FDA-approved as Zepbound for weight management and Mounjaro for type 2 diabetes), to tirzepatide alone at 5 mg, 10 mg, or 15 mg, or to placebo. Lilly refers to the combination product as EloraTZP.
What the Results Showed
At the highest tested combination dose, participants lost an average of 54.1 pounds, or 23.3% of body weight, over 48 weeks. That compares with 34.4 pounds, or 14.8%, in the group receiving the top approved dose of tirzepatide alone. On the trial's glycemic measure, the highest EloraTZP dose produced an average A1C reduction of up to 2.9 percentage points, compared with 2.4 points for tirzepatide alone.
Safety and Tolerability
The most common side effects were gastrointestinal, including nausea, diarrhea, and vomiting, generally described as mild to moderate and concentrated during dose escalation, a pattern consistent with other incretin and amylin-pathway drugs. Discontinuation due to side effects was noticeably higher in the combination arms, ranging from about 10.8% to 27.0%, compared with 2.9% for tirzepatide alone, a gap Lilly and outside researchers will need to explain and narrow as the program advances.
Why Combine an Amylin Drug With Tirzepatide
Amylin is a hormone the pancreas releases alongside insulin that promotes fullness through different brain signaling pathways than GLP-1 drugs use. Pairing an amylin-pathway drug like eloralintide with a GLP-1/GIP drug like tirzepatide is a strategy several companies are pursuing, on the theory that hitting complementary appetite pathways at once can produce greater weight loss than either mechanism alone, similar to the logic behind Novo Nordisk's cagrilintide-semaglutide combination, CagriSema. This site's guide to amylin agonists covers how eloralintide and other amylin-pathway candidates differ from GLP-1 drugs in more detail.
Where Eloralintide and Tirzepatide Each Stand Today
Tirzepatide is already FDA-approved and on the market as Zepbound and Mounjaro. Eloralintide is not FDA-approved for any use; Lilly has been studying it both as a standalone obesity treatment, where it previously reported up to 20.1% weight loss in a Phase 2 monotherapy trial, and in earlier combination work with tirzepatide, where a smaller 16-week Phase 2 study showed 17% weight loss. This new 48-week Phase 2b data is the most extensive combination dataset released so far, and Lilly said it plans to move the EloraTZP combination into Phase 3 testing in the fourth quarter of 2026.
The Bottom Line
EloraTZP is not an approved drug, and today's presentation is Phase 2b data on an investigational combination, not proof it will succeed in the larger trials needed for FDA approval. The elevated discontinuation rates in the higher-dose combination arms are a real signal worth watching as this moves forward. Anyone currently taking tirzepatide should not read this as a reason to change their treatment, and questions about any GLP-1 or amylin-pathway medication are worth raising directly with a prescribing physician.