Eli Lilly's eloraTZP, a combination of the amylin agonist eloralintide and tirzepatide, produced up to 23.3% mean weight loss at 48 weeks in adults with obesity and type 2 diabetes, according to Phase 2b data presented at EASD 2026 in Milan on September 30. Tirzepatide 15 mg alone, run as an active comparator in the same trial, reported 14.8%. A1C fell by up to 2.9 points from an 8.1% baseline.
The cost was tolerability. Lilly reported treatment discontinuation of 10.8% to 27.0% across the combination arms, against 2.9% for tirzepatide alone. That 8.5-point weight-loss gap and the dropout gap are the two numbers the Phase 3 program now has to reconcile.
Research-context information only. EloraTZP and eloralintide are investigational drugs not approved by the FDA. Protocols, doses, and reactions reported below come from published clinical trials and self-reported community sources. This article reports what has been documented, not what should be done. Possession or use of investigational drugs outside an authorized clinical trial may be illegal in your jurisdiction. Consult a licensed physician for personal medical decisions.
What the Phase 2b Trial Reported
The trial (NCT06603571) was a 48-week, double-blind, placebo-controlled study that randomized 367 adults in the US and Argentina across 10 arms. All participants had type 2 diabetes plus obesity or overweight, with a mean baseline weight of 105.4 kg (about 232 lb) and a mean A1C of 8.1%. Lilly said every combination arm met its primary endpoint (weight change) and key secondary endpoint (A1C change). Dr. Liana Billings presented the data.
Lilly's release led with the efficacy estimand, which estimates the effect in participants who stayed on treatment. A treatment-regimen estimand, which counts everyone randomized, has not yet been published. Treatment-regimen figures typically run lower than efficacy-estimand figures when discontinuation is high, as the discontinuation rates below suggest.
| Arm (48 weeks, efficacy estimand) | Weight change | A1C change from 8.1% |
|---|---|---|
| Eloralintide 3 mg + tirzepatide 5 mg | -13.2% | -2.2 pts |
| Eloralintide 6 mg + tirzepatide 5 mg | -19.4% | -2.7 pts |
| Eloralintide 6 mg + tirzepatide 10 mg | -19.9% | -2.6 pts |
| Eloralintide 9 mg + tirzepatide 15 mg | -23.3% | -2.9 pts |
| Tirzepatide 15 mg alone | -14.8% | -2.4 pts |
| Eloralintide alone (3, 6, 9 mg) | -8.2% to -12.3% | -1.1 to -1.4 pts |
| Placebo | -3.0% | -0.3 pts |
Sources: Eli Lilly release, September 30, 2026; HCPLive and Healio EASD coverage, October 1-2, 2026. Only the tirzepatide 15 mg row is a within-trial comparator.
Healio's conference report added depth on the top arms. On eloralintide 9 mg plus tirzepatide 15 mg, 63% of participants lost at least 20% of body weight and 25% lost at least 30%. A separate arm that started on tirzepatide 15 mg and added eloralintide from week 25 reported 19.9% weight loss at week 48, with 62% reaching the 20% mark. Billings told Healio: "We have not seen these degrees of weight loss in people with type 2 diabetes in previous studies."
Three Things the Numbers Show
At the top dose, the combination came close to the sum of its parts. Eloralintide alone reached up to 12.3% and tirzepatide 15 mg alone 14.8%. The 9 mg plus 15 mg combination reported 23.3%, not far below their sum. In the earlier non-diabetic Phase 2 trial, eloralintide monotherapy reported up to 20.1% at 48 weeks (Billings et al., Lancet 2025; PMID 41207310). The weaker monotherapy result here fits the pattern of diabetes populations losing less weight on every class tested so far.
Most of the extra weight loss came with low tirzepatide doses. Eloralintide 6 mg plus tirzepatide 5 mg reported 19.4%, already well above tirzepatide 15 mg alone. Going to tirzepatide 10 mg on top added only half a point. One reading of the arm data, not stated by Lilly, is that the amylin component drove much of the separation; the trial was not designed to isolate it. The pattern is the same lesson the eloraTZP Phase 1b cohorts hinted at.
Dropouts are the open question. The 27.0% top-end discontinuation figure is the highest reported for any arm, and Lilly attributed GI events mainly to dose escalation. Two caveats apply. The placebo arm also reported 16.7% discontinuation, which is unusually high and may reflect how Lilly defined the measure. And Healio reported that fewer than 10% of participants in any arm left the trial because of adverse events, which suggests many who stopped the drug stayed in follow-up. The full publication should clarify which definitions apply.
How It Compares in Diabetes Trials
Diabetes trials are the fair benchmark, since weight loss runs lower in this population on every incretin drug. No head-to-head trial exists outside eloraTZP's own tirzepatide arm, so the other figures come from separate studies with different durations and estimands. Tirzepatide and semaglutide are active ingredients in FDA-approved products; eloraTZP, retatrutide and survodutide are investigational.
| Compound | Mechanism | Diabetes-population weight loss (cross-trial, not head-to-head) | Source |
|---|---|---|---|
| Tirzepatide 10-15 mg | GIP + GLP-1 | 12.8-14.7% at 72 weeks | SURMOUNT-2 (Garvey et al., Lancet 2023) |
| Survodutide 6.0 mg | GLP-1 + glucagon | 13.1% at 76 weeks (efficacy) | SYNCHRONIZE-2 (NEJM 2026) |
| Retatrutide 12 mg | GIP + GLP-1 + glucagon | 20.8% at 80 weeks | TRIUMPH-2 (Bellido et al., Lancet 2026) |
| EloraTZP 9 + 15 mg | Amylin + GIP + GLP-1 | 23.3% at 48 weeks (efficacy) | Phase 2b, EASD 2026 |
SURMOUNT-2 (PMID 37385275) reported tirzepatide's figures under its treatment-regimen estimand. TRIUMPH-2, published in The Lancet on September 29 (PMID 42810372), reported 12.7% to 20.8% across retatrutide 4 to 12 mg versus 4.0% on placebo at 80 weeks. EloraTZP's 23.3% is the highest figure in the table, but it comes from a shorter, smaller Phase 2b trial on the more favorable estimand. Bloomberg's October 2 headline framed the meeting as Lilly upstaging Novo Nordisk in Milan.
Research-Use Supply and Verification
Nothing about the readout changes availability. EloraTZP is a two-molecule investigational product that exists only inside Lilly's trials, and eloralintide is not stocked by the research-peptide vendors we track. The trial results above come from clinical-grade drug supplied under trial conditions; they do not describe research-grade material and do not apply to it.
This article contains affiliate links; The Peptide Catalog may earn a commission if you purchase through them. Compounds referenced are sold for research use only and are not FDA-approved for human use.
Research-use-only listings exist for two related compounds. Neither is the trial product:
- Tirzepatide is widely listed as research-use-only material. Research-grade tirzepatide is not the FDA-approved finished product, and pricing per milligram varies several-fold across vendors. The tirzepatide buying guide tracks live per-vial pricing, COA status and coupon codes, and best tirzepatide vendors ranks in-stock sources.
- Cagrilintide is the amylin analog that research vendors list. It is a different molecule from eloralintide, developed by Novo Nordisk, and has its own trial record (Phase 3 data reported alongside semaglutide). The pairing of cagrilintide with an incretin agonist is documented in our cagrilintide + tirzepatide vs cagrilintide + semaglutide comparison; no trial has tested cagrilintide with tirzepatide, and the eloraTZP results do not transfer to that combination. Live listings are on best cagrilintide vendors.
Lot-specific third-party HPLC and mass-spec results are how buyers of research peptides verify identity and purity; the COA verification guide covers what to check.
