EloraTZP: eloralintide with tirzepatide

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What EloraTZP is

EloraTZP is Lilly's name for a combination of two of its drugs. Eloralintide activates amylin receptors, which help end meals by signalling fullness. Tirzepatide, the active ingredient of Mounjaro and Zepbound, activates the GIP and GLP-1 receptors. Together they engage three hormone pathways that the body normally switches on after eating, and Lilly says the combination has minimal activity at the calcitonin receptor, the related receptor that eloralintide was designed to avoid.

In the phase 2b trial the two drugs were given as two separate weekly injections. The product Lilly intends to take into phase 3 is a co-formulation, both drugs in one injection, which did not exist in this trial. A registered phase 1 study (NCT06916065), completed in January 2026, looked at the safety, tolerability and relative bioavailability of eloralintide given with tirzepatide in 188 adults with a BMI of 27 to 40; its results have not been posted.

How the phase 2b trial was run

The trial (NCT06603571) randomised 367 adults in the United States and Argentina, in equal numbers, to ten groups: placebo, three eloralintide-alone groups, tirzepatide 15 mg alone, four combinations, and one group that took tirzepatide and added eloralintide at week 24. It was double-blind and lasted 48 weeks.

To join, participants needed type 2 diabetes, a BMI of 27 or more, and an HbA1c between 7.0% and 10.5% while on diet and exercise alone or a stable dose of metformin, with or without an SGLT2 inhibitor, for at least three months. They had to have kept a steady weight for the three months before randomisation. On average they weighed 105.4 kg (232.4 lb) and had an HbA1c of 8.1%.

Doses were reached in steps. Eloralintide started at 1 or 3 mg. Tirzepatide started at 2.5 mg and went up every four weeks to its target dose. In the add-on group, eloralintide began at week 24 at 3 mg and rose to 6 mg four weeks later.

The primary question was whether a combination beat placebo on percentage weight change at 48 weeks. Every comparison with tirzepatide alone or eloralintide alone, including the headline comparison with tirzepatide 15 mg, was a secondary endpoint. The results were presented at EASD 2026 in Milan; the lead author is Liana K. Billings of Endeavor Health.

Results by group

Lilly reported these 48-week figures under the efficacy estimand:

Group	Weight change	Weight change (lb)	HbA1c change (points)
Eloralintide 9 mg + tirzepatide 15 mg	-23.3%	-54.1 lb	-2.9
Eloralintide 6 mg + tirzepatide 10 mg	-19.9%	-46.2 lb	-2.6
Eloralintide 6 mg + tirzepatide 5 mg	-19.4%	-45.1 lb	-2.7
Eloralintide 3 mg + tirzepatide 5 mg	-13.2%	-30.7 lb	-2.2
Tirzepatide 15 mg	-14.8%	-34.4 lb	-2.4
Eloralintide 6 mg	-12.3%	-28.6 lb	-1.4
Eloralintide 9 mg	-11.1%	-25.8 lb	-1.3
Eloralintide 3 mg	-8.2%	-19.1 lb	-1.1
Placebo	-3.0%	-7.0 lb	-0.3

Read down the weight column and a few things stand out. Every combination beat placebo, which was the primary question. Eloralintide 6 mg with tirzepatide 5 mg (19.4%) took off more weight than tirzepatide 15 mg alone (14.8%), and adding a larger tirzepatide dose to the same eloralintide dose moved the result only half a point (19.9%). The top combination, eloralintide 9 mg with tirzepatide 15 mg, gave the largest loss, 23.3%. On its own, eloralintide did slightly worse at 9 mg (11.1%) than at 6 mg (12.3%).

HbA1c moved less dramatically. Three of the four combinations lowered it more than tirzepatide 15 mg alone (2.6 to 2.9 points against 2.4), while the smallest combination lowered it less (2.2). Eloralintide alone lowered HbA1c by 1.1 to 1.4 points.

Lilly's figures come without confidence intervals, p-values or group sizes, so the size of the uncertainty around each number is not yet known. With 367 people across ten groups, each group held about 37.

What "efficacy estimand" means here

Lilly defines the efficacy estimand as the effect expected had every randomised participant stayed on treatment for all 48 weeks, allowing for interrupted or reduced doses. It answers the question of what the drug does in people who keep taking it. It does not answer what happens to a group of people who are offered it, some of whom stop.

That distinction matters more than usual in this trial, because a large share of people stopped. Between 10.8% and 27.0% of participants on the combinations stopped treatment because of adverse events, against 2.9% on tirzepatide alone and up to 10.8% on eloralintide alone. Lilly also reported 16.7% on placebo, without explaining it. Results under a treatment-regimen estimand, which counts everyone randomised, have not been reported; when many people stop, as here, that estimand typically comes out lower.

Side effects and stopping

Lilly reported that the most common adverse events were gastrointestinal, that most were mild or moderate, that they occurred mainly while doses were being raised, and that they were more frequent on the combinations than on either drug alone. It did not publish rates for individual side effects by group.

The earlier eloralintide trials suggest what to look for when the full data appear. In eloralintide's 48-week phase 2 trial in adults without diabetes, nausea depended heavily on how the dose was started: 64% of people who began on 6 mg had nausea, against 25% of those who climbed from 3 mg, and 14% on placebo. Fatigue reached 43% on 9 mg, against 12% on placebo. Whether the combination adds to tirzepatide's own gastrointestinal effects, and by how much, is a question the phase 2b paper will need to answer.

Lilly says phase 3 will use an optimised escalation schedule. In eloralintide's own phase 2, a slower climb cut nausea sharply, which is the usual reason for one.

What has not been reported yet

As of October 2, 2026, neither Lilly's announcement nor ClinicalTrials.gov gives:

• results under a treatment-regimen estimand;
• how many people were in each group, and how many finished;
• the rate of each side effect, including nausea, vomiting, fatigue and hypoglycaemia, by group;
• the result for the group that added eloralintide at week 24 (ten groups were randomised and Lilly's table lists nine);
• confidence intervals or p-values for any comparison;
• a peer-reviewed paper.

The registry record was last updated on September 29, 2026 and had no posted results on October 2. Each of these gaps changes how far the headline can be taken, and each should close when the trial is published.

The co-formulation and phase 3

Lilly says it will start phase 3 trials of an EloraTZP co-formulation by the end of 2026, in the fourth quarter, with an optimised escalation schedule. No phase 3 trial of the combination appears among the 22 eloralintide studies on ClinicalTrials.gov as of October 2, 2026. Separately, eloralintide on its own is already in five phase 3 trials, the ENLIGHTEN programme, each measuring weight at 64 weeks.

For a combination to be approved, regulators generally expect evidence that each component contributes. This trial was built to show that, with eloralintide-alone, tirzepatide-alone and placebo groups beside the combinations, and phase 3 will need to show it again at scale.

What phase 3 will have to show

• Results that count everyone. A treatment-regimen result for the combination, not only an efficacy estimand.
• Fewer people stopping. Whether the slower escalation brings discontinuation for adverse events down from as high as 27%.
• The full-dose comparison. Whether the combination beats tirzepatide 15 mg alone by a margin that justifies a second drug, over more than 48 weeks.
• People without diabetes. This trial enrolled only people with type 2 diabetes, who tend to lose less weight on the same drugs.
• The single injection. That the co-formulation behaves like the two separate injections tested here.

Comparisons

EloraTZP is not the first amylin and incretin pairing. Novo Nordisk's CagriSema combines the amylin analogue cagrilintide with semaglutide and has reported phase 3 results, including in type 2 diabetes. Retatrutide, Lilly's own triple agonist, reaches three receptors with one molecule. None of these has been tested against EloraTZP, and the published figures differ in population, length and estimand, so they cannot be ranked from the numbers alone. The EloraTZP Wire post works through the retatrutide comparison figure by figure.

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Frequently asked questions

What is EloraTZP?

EloraTZP is Eli Lilly's name for eloralintide, an amylin receptor agonist, combined with tirzepatide, a GIP and GLP-1 receptor agonist. It was tested as two separate weekly injections; Lilly plans a single-injection version for phase 3.

How much weight did people lose on EloraTZP?

In the 48-week phase 2b trial in adults with type 2 diabetes, the combinations cut weight by 13.2% to 23.3%, against 14.8% on tirzepatide 15 mg alone and 3.0% on placebo, under the efficacy estimand, which assumes everyone stayed on treatment.

Is EloraTZP better than tirzepatide alone?

In this trial the top combination lost more weight than tirzepatide 15 mg (23.3% against 14.8%), but more people stopped because of side effects (10.8% to 27.0% on the combinations against 2.9%), and the comparison was a secondary endpoint. Phase 3 will test it properly.

Is EloraTZP available?

No. It is investigational and approved nowhere as of October 2, 2026, and there is no lawful way to obtain it outside Lilly's clinical trials.

When could EloraTZP be approved?

There is no date. Lilly plans to start phase 3 trials by the end of 2026, and an application would normally follow their results.

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Sources

1. Eli Lilly and Company. EloraTZP (combination of eloralintide and tirzepatide) phase 2b results. News release, September 30, 2026. Read October 2, 2026.
2. ClinicalTrials.gov NCT06603571 (EloraTZP phase 2b; last updated September 29, 2026) and NCT06916065 (phase 1 relative bioavailability of eloralintide with tirzepatide). Read October 2, 2026.
3. Billings LK, et al. "Eloralintide, a selective amylin receptor agonist for the treatment of obesity: a 48-week phase 2, multicentre, double-blind, randomised, placebo-controlled trial." Lancet. 2025;406(10520):2631-2643.

Medical disclaimer: This page is for education only and is not medical advice. EloraTZP and eloralintide are investigational and not approved for use. Do not start, stop, or self-administer any drug based on this page; consult a licensed clinician.