EloraTZP Phase 2b: 23.3% Weight Loss in Type 2 Diabetes, and Up to 27% Stopped for Side Effects

What the trial tested

The trial enrolled 367 adults in the United States and Argentina who had type 2 diabetes and a BMI of 27 or more. Their HbA1c had to be between 7.0% and 10.5% on diet and exercise alone or on a stable dose of metformin, with or without an SGLT2 inhibitor. On average they weighed 105.4 kg (232.4 lb) and had an HbA1c of 8.1% at the start.

Participants were randomised evenly to ten groups for 48 weeks: placebo, eloralintide alone, tirzepatide alone, and several combinations. The two drugs were given as separate weekly injections. EloraTZP is Lilly's name for the pair; the single-injection version it plans to test next was not part of this trial. Doses were raised in steps: eloralintide started at 1 or 3 mg, and tirzepatide started at 2.5 mg and went up every four weeks.

The primary question was narrow: did the combination beat placebo on weight? Every comparison with tirzepatide or eloralintide alone was a secondary endpoint. The results were presented at EASD 2026 in Milan, and Lilly announced them on September 30.

The numbers Lilly reported

Change in body weight and in HbA1c at week 48:

• Eloralintide 9 mg with tirzepatide 15 mg: weight down 23.3%, HbA1c down 2.9 points
• Eloralintide 6 mg with tirzepatide 10 mg: 19.9%, 2.6 points
• Eloralintide 6 mg with tirzepatide 5 mg: 19.4%, 2.7 points
• Eloralintide 3 mg with tirzepatide 5 mg: 13.2%, 2.2 points
• Tirzepatide 15 mg alone: 14.8%, 2.4 points
• Eloralintide alone: 8.2% at 3 mg, 12.3% at 6 mg and 11.1% at 9 mg, with HbA1c down 1.1 to 1.4 points
• Placebo: 3.0%, 0.3 points

Two details are easy to miss. Eloralintide 6 mg with only 5 mg of tirzepatide took off more weight than the full 15 mg of tirzepatide on its own, 19.4% against 14.8%. And eloralintide by itself did slightly worse at 9 mg than at 6 mg in this trial.

What "up to 23.3%" assumes

Every figure above is an efficacy estimand. Lilly defines it as the result expected if every randomised participant had stayed on treatment for all 48 weeks, allowing for interrupted or reduced doses.

In this trial that assumption carries weight, because many people did not stay on treatment. Between 10.8% and 27.0% of participants on the combinations stopped because of adverse events, against 2.9% on tirzepatide alone and up to 10.8% on eloralintide alone. Lilly also reported 16.7% in the placebo group, without explaining it. Most side effects were gastrointestinal and mild or moderate, they came mainly while doses were being raised, and they were more common on the combinations than on either drug alone.

Several things have not been published yet: results under a treatment-regimen estimand, which counts everyone randomised whether or not they kept taking the drug; how many people were in each group; how often each side effect occurred in each group; and the result for one group that began eloralintide only at week 24, on top of tirzepatide. That group is the tenth of the ten randomised, and Lilly's table lists nine. There is no journal paper, and ClinicalTrials.gov had no posted results on October 2.

Diabetes lowers the ceiling

Trials in people with type 2 diabetes tend to report smaller weight losses than trials of the same drug in people without it, and two of Lilly's own pairs show the size of the gap. Retatrutide 12 mg cut weight by 25.0% at 80 weeks in adults without diabetes in TRIUMPH-1, and by 18.8% over the same 80 weeks in adults with type 2 diabetes in TRIUMPH-2. Eloralintide 6 mg gave about 18% in its phase 2 trial in people without diabetes and 12.3% in this one, both under the efficacy estimand.

So 23.3% is a large result for this population. It is also not comparable with figures from trials that excluded diabetes.

Why the retatrutide comparison does not hold up

Comparisons with retatrutide, Lilly's triple agonist, started the day the results came out. The closest counterpart is TRIUMPH-2, retatrutide's phase 3 trial in adults with obesity and type 2 diabetes, published in The Lancet the day before. Its top dose, 12 mg, cut weight by 18.8% against 5.1% on placebo, which on its face is below EloraTZP's 23.3%.

The two numbers were not measured the same way. TRIUMPH-2 ran for 80 weeks with about 290 people per group; this trial ran for 48 weeks with about 37. TRIUMPH-2 reports a treatment-regimen estimand, which keeps the people who stopped the drug in the result; EloraTZP's figure assumes nobody stopped, in a trial where up to 27% of a combination group did. The placebo groups also lost different amounts, 5.1% against 3.0%. Subtracting placebo leaves 13.8 points for retatrutide and 20.3 for EloraTZP, still under different estimands. None of the 22 eloralintide trials registered on ClinicalTrials.gov includes retatrutide.

What the trial does show is narrower and still useful: in people with type 2 diabetes, EloraTZP produced more weight loss than tirzepatide alone, if everyone stayed on treatment. How it compares with retatrutide is not known.

What happens next

Lilly says it will start phase 3 trials of a single-injection EloraTZP by the end of 2026, using a revised dose-escalation schedule. Eloralintide alone is already in five phase 3 trials, the ENLIGHTEN programme, each measuring weight at 64 weeks: obesity with and without type 2 diabetes, sleep apnoea, knee osteoarthritis, and people still living with obesity on a weekly incretin. Neither treatment is approved anywhere, and neither is available outside clinical trials.

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