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    Research 9 min readOct 25, 2026 Fact-checked

    EloraTZP: Eloralintide Plus Tirzepatide Trial Results

    EloraTZP pairs eloralintide with tirzepatide. In a type 2 diabetes Phase 2b the top arm lost 23.3% at 48 weeks on the efficacy estimand. Phase 3 is next.

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    BioChonch

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    Evidence notes from published research and trial registries. Educational information, not medical advice.

    Key Takeaway

    EloraTZP pairs eloralintide with tirzepatide. In a type 2 diabetes Phase 2b the top arm lost 23.3% at 48 weeks on the efficacy estimand. Phase 3 is next.

    EloraTZP is two Lilly drugs given together: eloralintide, a selective amylin receptor agonist, and tirzepatide, the GIP and GLP-1 receptor agonist sold as Mounjaro and Zepbound. In a 48-week Phase 2b trial of 367 adults with obesity or overweight and type 2 diabetes, the top arm, eloralintide 9 mg plus tirzepatide 15 mg, lost 23.3% of body weight on average. Tirzepatide 15 mg alone lost 14.8% and placebo 3.0%. Those are efficacy-estimand figures, which assume everyone stayed on treatment (Lilly's results release). In the combination arms, 10.8% to 27.0% of participants stopped treatment because of adverse events, depending on the arm. The trial used two separate injections; Phase 3 moves to one co-formulated shot.

    EloraTZP is not approved anywhere, and this page covers what its trials have shown, not how to use either drug.

    The name, and one shot or two

    The name joins Elora, for eloralintide (Lilly code LY3841136), to TZP, Lilly's shorthand for tirzepatide. Unlike amycretin, it is not one new molecule.

    Co-administered or co-formulated? Both, at different stages. In Phase 2b the drugs were given as separate injections. The Phase 3 records describe an "eloralintide and tirzepatide coformulation" coded LY900043. A Phase 1 relative-bioavailability study of the pair, NCT06916065, finished in January 2026 without saying which formulation it used.

    Eloralintide is a once-weekly injection with a half-life of about 14 days (Phase 1 paper). Our eloralintide and tirzepatide pages cover each drug on its own.

    How the Phase 2b trial was set up

    NCT06603571 ran in the US and Argentina; Lilly presented it at EASD in Milan on September 30, 2026 (schedule).

    Design point NCT06603571
    Population Adults with a BMI of 27 or more and type 2 diabetes, HbA1c 7.0% to 10.5%, on diet and exercise or metformin with or without an SGLT2 inhibitor
    Baseline 105.4 kg (232.4 lb) and an A1C of 8.1% on average
    Arms Ten, randomized in equal numbers: placebo, three eloralintide doses alone, tirzepatide 15 mg, four pairings, and an arm adding eloralintide to tirzepatide at week 24 (3 mg, then 6 mg)
    Escalation Pairings started at eloralintide 1 or 3 mg plus tirzepatide 2.5 mg and stepped up every four weeks
    Primary endpoint Percent weight change at week 48, EloraTZP against placebo; comparisons with tirzepatide alone were secondary

    Sources: registry and Lilly. Lilly reported nothing from the tenth arm. Ten arms from 367 people means about 37 per arm, which matters for every figure below.

    EloraTZP results by arm

    Arm, weekly doses tested in NCT06603571 Mean weight loss Pounds lost A1C drop, points
    Eloralintide 3 mg + tirzepatide 5 mg 13.2% 30.7 2.2
    Eloralintide 6 mg + tirzepatide 5 mg 19.4% 45.1 2.7
    Eloralintide 6 mg + tirzepatide 10 mg 19.9% 46.2 2.6
    Eloralintide 9 mg + tirzepatide 15 mg 23.3% 54.1 2.9
    Tirzepatide 15 mg 14.8% 34.4 2.4
    Eloralintide 3 mg 8.2% 19.1 1.1
    Eloralintide 6 mg 12.3% 28.6 1.4
    Eloralintide 9 mg 11.1% 25.8 1.3
    Placebo 3.0% 7.0 0.3

    Source: Lilly, September 30, 2026, 48 weeks, efficacy estimand. The release gives no confidence intervals, and PubMed listed no paper on this trial as of October 24.

    What the table does and does not show

    The 23.3% headline is not the most telling number. Look at eloralintide 6 mg plus tirzepatide 5 mg: 19.4%, against 14.8% for tirzepatide 15 mg, on a third of the tirzepatide dose (Lilly). If Phase 3 repeats that, amylin could buy more weight loss with less incretin. For now it is a secondary comparison between two small arms.

    Eloralintide alone looked weaker here than in its first Phase 2. In adults without diabetes, 9 mg produced 20.1% at 48 weeks (Lancet trial, our phase 2 review); here the same dose produced 11.1%, no better than 6 mg. Diabetes explains part of that gap, because it blunts weight loss across the class. Tirzepatide 15 mg gave 20.9% in SURMOUNT-1, which excluded diabetes, and 14.7% in SURMOUNT-2, which required it, both at 72 weeks.

    Then the estimand. FDA's draft obesity guidance asks for treatment-policy analyses that count everyone randomized, and with up to 27.0% stopping treatment for adverse events, those figures are likely to come in lower, by an amount nobody outside Lilly knows.

    Side effects and who stopped

    Lilly says gastrointestinal events were the most common, mostly mild or moderate, clustered in dose escalation, and more frequent in the combination arms than with either drug alone. Discontinuation for adverse events was 10.8% to 27.0% with EloraTZP, 0% to 10.8% with eloralintide alone, 2.9% with tirzepatide and 16.7% with placebo (Lilly).

    That placebo figure is a warning about small arms: more placebo participants stopped over adverse events than tirzepatide participants did. If arms stayed near equal size, 27.0% is roughly ten people and 2.9% roughly one. Until a full paper gives confidence intervals, we treat every per-arm rate here as soft. Lilly says Phase 3 will use an "optimized escalation schedule," which suggests it sees the step-up pace as part of the problem.

    The release leaves out per-arm nausea and fatigue, which arm reached 27.0%, and heart rate. Eloralintide's own trials say where to look. In the monotherapy Phase 2, fatigue hit 43% on 9 mg against 12% on placebo, and nausea 64% on 6 mg against 14% (Lancet).

    Heart rate is harder to call. In Phase 1, mean pulse fell 14.4 beats per minute on 12 mg against 3.4 on placebo at week 12, with no symptomatic bradycardia (Phase 1 paper). GLP-1 drugs tend to raise heart rate (2026 review), so what the pair does to pulse is an open question, and the Phase 2b excluded anyone with a resting pulse under 60 or over 100 (registry). The same Phase 1 logged mood-related events, including depressed mood, in four of 73 people on eloralintide (Phase 1 paper).

    Why pair amylin with an incretin?

    Amylin is released with insulin after meals. It curbs glucagon, slows gastric emptying and signals fullness through the brain (Phase 1 paper). GIP and GLP-1 use other receptors, so the effects can stack. CagriSema, an amylin analog paired with the GLP-1 drug semaglutide, showed they do, and Lilly's researchers note that pairing also "brings additivity for gastrointestinal adverse events" (same paper).

    Lilly's bet is selectivity. In cell assays eloralintide activated the human amylin 1 receptor about 12 times more potently than the calcitonin receptor, and in rats it caused less conditioned taste avoidance than cagrilintide (discovery paper). Lilly says EloraTZP has "minimal activity at the calcitonin receptor" (Lilly). No human trial has tested that head to head; see eloralintide vs cagrilintide and amylin analogs compared.

    The other half of the bet is the partner. In the open-label REDEFINE 4, people on CagriSema lost 23.0% against 25.5% on tirzepatide 15 mg at 84 weeks, had everyone stayed on treatment, and missed non-inferiority (Novo Nordisk). Lilly is adding amylin to the incretin CagriSema could not match. A Phase 1 result at EASD 2026 showed 17% weight loss at 16 weeks with eloralintide 3 mg on top of tirzepatide 5 mg, against 10% on tirzepatide 5 mg alone (Lilly).

    EloraTZP next to other diabetes trials

    Length, estimand and populations differ, so read the rows as context rather than a ranking.

    Trial Drugs, top dose tested Weeks Estimand Mean weight loss Placebo
    NCT06603571, Phase 2b Eloralintide 9 mg + tirzepatide 15 mg 48 Efficacy 23.3% 3.0%
    SURMOUNT-2, Phase 3 Tirzepatide 15 mg 72 Treatment-regimen 14.7% 3.2%
    REDEFINE 2, Phase 3 Cagrilintide 2.4 mg + semaglutide 2.4 mg 68 Treatment-policy 13.7% 3.4%

    CagriSema is much further along. Novo announced its FDA filing on December 18, 2025, ten months before the EloraTZP Phase 3 trials appeared on the registry.

    Without diabetes, and what comes next

    Apart from that short Phase 1 result, every EloraTZP figure comes from people with type 2 diabetes. The real test for everyone else is AMPLIFY-1 (NCT07881432): about 2,115 adults with a BMI of 35 or more and no diabetes, randomized to five EloraTZP doses, tirzepatide alone, eloralintide alone or placebo, measured at week 100. That BMI floor sits well above ENLIGHTEN-1's 30, or 27 with a weight-related condition (NCT07321886), which reads like a combination aimed at people with more weight to lose.

    AMPLIFY-2 (NCT07881458) pits EloraTZP against tirzepatide in about 1,000 adults with type 2 diabetes. It is due to start in November 2026 and AMPLIFY-1 in December; both list primary completion in October 2029 and no milligram doses. Our eloralintide Phase 3 trials and timeline lists every registered study and estimates approval timing.

    No registered trial pairs eloralintide with retatrutide. For the two as single drugs, see eloralintide vs retatrutide.

    Sources

    Frequently asked

    Not in Phase 2b, where eloralintide and tirzepatide went in as separate weekly injections. The Phase 3 trials use a single co-formulated product, coded LY900043.

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    BioChonchResearch editorial

    Evidence notes from published research and trial registries. Educational information, not medical advice.