Lilly's EloraTZP Combo Tops Tirzepatide Alone in Phase 2b Obesity-Diabetes Trial

On September 30, 2026, Eli Lilly and Company announced Phase 2b results for EloraTZP, an investigational combination of eloralintide (a selective amylin receptor agonist) and tirzepatide (the dual GIP/GLP-1 agonist in Zepbound and Mounjaro). According to the company's release, the data were presented at the 62nd Annual Meeting of the European Association for the Study of Diabetes (EASD) in Milan. EloraTZP is not FDA-approved; the readout describes a mid-stage trial, not a regulatory decision.

The 48-week, double-blind, placebo-controlled study (NCT06603571) randomized 367 adults with obesity or overweight and type 2 diabetes in the U.S. and Argentina. Lilly said the primary objective was to show that eloralintide plus tirzepatide was superior to placebo for percent change in body weight at 48 weeks. Mean baseline weight was about 232.4 lb (105.4 kg) and mean baseline A1C was 8.1%, according to the company.

In the Phase 2b study, eloralintide and tirzepatide were given as separate injections; Lilly said it plans to advance a co-formulation into Phase 3. The efficacy figures below use the company's efficacy estimand, which estimates results as if all randomized participants had remained on study intervention for 48 weeks.

Lilly reported that the highest EloraTZP dose tested — eloralintide 9 mg plus tirzepatide 15 mg — produced average weight loss of 23.3% (about 54.1 lb) and an A1C reduction of 2.9% at 48 weeks. Tirzepatide 15 mg alone, in the same trial, was associated with 14.8% weight loss (about 34.4 lb) and a 2.4% A1C reduction. Lower combination doses also met the company's primary and secondary endpoints, with weight-loss figures ranging from 13.2% to 19.9% depending on the pair.

Eloralintide alone reduced weight by up to 12.3% and A1C by up to 1.4% in this study, while placebo was associated with about 3.0% weight loss and a 0.3% A1C change, according to the release. Cross-trial comparisons with other obesity drugs are not appropriate here; these figures come from one Phase 2b dataset in people who already have type 2 diabetes.

Lilly said the most common adverse events were gastrointestinal and generally mild or moderate, mainly during dose escalation, and occurred more often with the combination than with either agent alone. Treatment discontinuation due to adverse events ranged from 10.8% to 27.0% with EloraTZP, versus 2.9% with tirzepatide 15 mg and 16.7% with placebo, according to the company. Phase 3 will need to show whether an optimized escalation schedule improves tolerability.

Lilly said it will initiate Phase 3 trials of an EloraTZP co-formulation in the fourth quarter of 2026, while Phase 3 studies of eloralintide alone for obesity are already underway. That timeline is a company plan, not an approval date. Readers comparing marketed pens such as Zepbound or Wegovy should treat this as pipeline news: investigational combinations can look strong in mid-stage trials and still fail, be delayed, or carry different risk profiles in larger studies. Anyone considering a change in diabetes or weight-management therapy should discuss options with a licensed clinician rather than treating a conference readout as a prescribing guide.