Enicepatide (development code CT-388) is an investigational once-weekly injectable that activates both the glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors. Roche is developing it for obesity, type 2 diabetes and related cardiometabolic conditions. Tirzepatide, which is FDA-approved, acts on the same two receptors.
In a 48-week Phase 2 trial in adults with obesity or overweight, the highest dose (24 mg) produced 22.5% placebo-adjusted weight loss under Roche’s efficacy estimand (Roche, Jan. 27, 2026). A second Phase 2 trial, in adults with type 2 diabetes, reported a 2.65-percentage-point HbA1c (glycated hemoglobin) reduction and 15.5% mean weight loss at 48 weeks (Roche, Sept. 22, 2026).
Enicepatide is not approved. Roche reported in September 2026 that two Phase 3 chronic weight-management studies, ENITH-1 and ENITH-2, were underway. No head-to-head trial has compared enicepatide with tirzepatide, and results from separate trials are not directly comparable.
Medical information: This page summarizes clinical research and company announcements. It is not individual medical advice. Enicepatide is investigational, and decisions about obesity or diabetes treatment are made with a qualified healthcare professional.
Information current as of September 29, 2026.
In this article
- Enicepatide at a glance
- What is enicepatide (CT-388)?
- How does enicepatide work?
- Enicepatide weight-loss results
- Enicepatide results in type 2 diabetes
- Enicepatide side effects
- Enicepatide vs tirzepatide
- What is still unknown about CT-388?
- Is enicepatide available?
- What happens next for enicepatide?
- Frequently asked questions about enicepatide
- Summary
Enicepatide at a glance
| Question | Current evidence (as of September 2026) |
|---|---|
| What is enicepatide? | An investigational once-weekly GLP-1/GIP receptor agonist from Roche |
| Other names | CT-388, RO7795068, RG6640 |
| Administration studied | Once-weekly subcutaneous injection |
| Highest Phase 2 obesity dose | 24 mg |
| Phase 2 obesity result | 22.5% placebo-adjusted weight loss at 48 weeks (efficacy estimand); 18.3% under the treatment-regimen estimand |
| 20% or more weight loss | 47.8% of participants receiving 24 mg |
| 30% or more weight loss | 26.1% of participants receiving 24 mg |
| Phase 2 type 2 diabetes result | 15.5% mean weight loss and a 2.65-percentage-point HbA1c reduction at 48 weeks (24 mg) |
| Most common adverse events | Gastrointestinal, mostly mild to moderate |
| FDA-approved? | No |
| Phase 3? | Yes: ENITH-1 and ENITH-2 (weight management) are underway |
| Same receptor targets as tirzepatide? | Yes, GLP-1 and GIP |
| Shown to be better than tirzepatide? | No head-to-head trial exists |
What is enicepatide (CT-388)?
Enicepatide is an experimental dual GLP-1/GIP receptor agonist. It originated at Carmot Therapeutics, which Roche acquired, and it was widely discussed under the code name CT-388 before Roche adopted the generic name enicepatide.
Like tirzepatide, it activates the GLP-1 receptor (GLP-1R) and the GIP receptor (GIPR), which are involved in the body’s response to nutrients. The two molecules are not identical. Roche describes enicepatide as a “dually biased” GLP-1/GIP receptor agonist studied as a once-weekly injection to reduce appetite, manage body weight and improve glucose regulation (Roche, Sept. 22, 2026).
How does enicepatide work?
Drugs that activate GLP-1 and GIP receptors can affect appetite, food intake, insulin secretion, glucose control and body weight.
What sets CT-388 apart is its signaling design. A peer-reviewed paper describing CT-388 reports that it is biased toward cAMP signaling at both receptors while causing relatively little receptor internalization compared with the receptors’ natural ligands, and the authors proposed this could help preserve receptor activity (PubMed 41319798). Roche similarly states that enicepatide has minimal to no beta-arrestin recruitment on either receptor, which “minimises receptor internalisation and consequent desensitisation.”
That is a mechanistic distinction. Whether it produces better weight loss, glucose control, tolerability or long-term outcomes than existing dual agonists can only be shown by large randomized trials.
Enicepatide weight-loss results
The main obesity study so far is CT-388-103, registered as NCT06525935. It was a randomized, double-blind, placebo-controlled Phase 2 trial in adults with obesity or overweight and at least one weight-related condition, without type 2 diabetes. ClinicalTrials.gov lists actual enrollment of 469 participants, while the ADA scientific abstract reports 467 randomized. Target doses of 4, 8, 12, 16 and 24 mg were given once weekly for 48 weeks (ADA 2026 abstract).
At 24 mg, Roche reported 22.5% placebo-adjusted weight loss at week 48 under the efficacy estimand, and said weight loss had not reached a plateau (Roche, Jan. 27, 2026). Responder rates at 24 mg were:
| Weight loss at 48 weeks | Participants on enicepatide 24 mg |
|---|---|
| At least 5% | 95.7% |
| At least 10% | 87.0% |
| At least 20% | 47.8% |
| At least 30% | 26.1% |
Roche also reported that 54% of participants on 24 mg had a BMI below 30 kg/m² by week 48, versus 13% on placebo. Among participants with prediabetes at baseline, 73% on 24 mg returned to normal blood glucose, versus 7.5% on placebo (Roche, Jan. 27, 2026).
Understanding the 22.5% figure
Roche’s 22.5% figure is placebo-adjusted and uses an efficacy estimand. Under a treatment-regimen estimand, which accounts differently for treatment discontinuation and other events, Roche reported 18.3% placebo-adjusted weight loss in the same trial.
The original SURMOUNT-1 tirzepatide study reported a different 22.5%: mean weight loss from baseline at 72 weeks for tirzepatide 15 mg under its efficacy estimand, with a placebo-adjusted difference of 20.1 percentage points (NEJM, SURMOUNT-1). The two 22.5% figures are not equivalent, because the estimands, placebo responses, durations, participants, dose schedules and protocols all differ.
Enicepatide results in type 2 diabetes
On September 22, 2026, Roche released Phase 2 results from CT-388-104 (NCT06628362). The randomized, double-blind, placebo-controlled trial enrolled 447 adults with type 2 diabetes and overweight or obesity, who received once-weekly enicepatide or placebo for 48 weeks. Roche reported the following for the highest titrated dose, 24 mg:
| Outcome at week 48 | Enicepatide 24 mg |
|---|---|
| Baseline mean HbA1c | 8.1% |
| Mean HbA1c reduction | 2.65 percentage points |
| Participants reaching HbA1c of 6.5% or lower | 90% |
| Participants reaching HbA1c below 5.7% | 62% |
| Mean body-weight reduction | 15.5% |
| Weight-loss plateau observed | No |
In participants whose baseline HbA1c exceeded 8.5%, Roche reported a 4.13-percentage-point reduction (Roche, Sept. 22, 2026). Roche described the trial as meeting both primary endpoints. These are Phase 2 findings and do not carry the weight of tirzepatide’s completed Phase 3 program.
Enicepatide side effects
Roche reported that gastrointestinal adverse events were the most commonly reported and that most were mild to moderate. The company reported no new safety signals in either Phase 2 announcement (Roche, Sept. 22, 2026). In the earlier Phase 1 program, reported gastrointestinal effects included nausea, vomiting, diarrhea and decreased appetite, and most treatment-emergent adverse events were mild or moderate (ADA 2023 abstract).
The Phase 2 announcements do not give event-by-event percentages for each adverse effect, so a full frequency table is not available. No prescribing label exists because the drug is not approved.
Discontinuation because of adverse events
| Trial | Enicepatide groups | Placebo |
|---|---|---|
| Phase 2 obesity (CT-388-103) | 5.9% | 1.3% |
| Phase 2 type 2 diabetes (CT-388-104) | 2.0% | 0% |
Phase 3 trials with more participants and longer exposure are expected to characterize uncommon and long-term risks.
Enicepatide vs tirzepatide
Both are once-weekly peptide injections that activate GLP-1 and GIP receptors, but the evidence behind them differs greatly.
| Feature | Enicepatide (CT-388) | Tirzepatide |
|---|---|---|
| Targets | GLP-1 and GIP receptors | GLP-1 and GIP receptors |
| Administration | Once-weekly injection in trials | Once-weekly injection |
| Development status | Investigational | Approved |
| Obesity evidence | Phase 2 completed; Phase 3 underway | Multiple Phase 3 trials completed |
| Highest obesity dose discussed | 24 mg in Phase 2 | 15 mg (approved maximum) |
| Signaling design | Described as dually biased / cAMP-biased | Dual GIP/GLP-1 receptor agonist |
| Prescription brands | None | Zepbound and Mounjaro |
| Long-term clinical evidence | Limited | Multi-year data |
| Head-to-head trial | None | None |
FDA approved tirzepatide as Zepbound for chronic weight management in 2023, and it is also marketed as Mounjaro for type 2 diabetes (FDA).
Weight loss: separate trials, no direct comparison
No head-to-head trial has compared the two drugs, so no comparative conclusion is available. The separate trial results are:
- Tirzepatide (SURMOUNT-1). Adults with obesity or overweight without diabetes on 15 mg had a 20.9% mean weight reduction at 72 weeks under the treatment-regimen estimand and 22.5% under the efficacy estimand (NEJM).
- Enicepatide (CT-388-103). 22.5% placebo-adjusted weight loss at 48 weeks for 24 mg under the efficacy estimand, with no plateau observed (Roche).
A valid comparison would randomize similar participants to each drug under one protocol, follow them for the same duration, and use the same estimand and outcome measures.
Blood-sugar results
In its September 2026 Phase 2 trial, enicepatide 24 mg produced a 2.65-percentage-point mean HbA1c reduction at 48 weeks from a baseline of 8.1%, and 62% of participants at that dose reached an HbA1c below 5.7% (Roche).
In SURPASS-2, tirzepatide 5, 10 and 15 mg lowered HbA1c by 2.01, 2.24 and 2.30 percentage points at week 40, and 46% of participants on 15 mg reached an HbA1c below 5.7% (NEJM, SURPASS-2). These were separate studies with different participants, protocols, background treatments and statistical methods, so 2.65 and 2.30 cannot be compared directly.
What is still unknown about CT-388?
Phase 2 indicates whether a drug warrants further study, and Phase 3 tests whether the findings hold across a larger and more diverse population. For enicepatide, evidence is still missing on:
- long-term safety and weight maintenance over multiple years;
- outcomes after treatment is stopped;
- uncommon adverse reactions and results in important patient subgroups;
- cardiovascular outcomes; and
- whether its receptor-signaling profile gives a clinical advantage over existing dual incretin drugs.
A compelling mechanism does not by itself show a better outcome in patients.
Is enicepatide available?
No. Enicepatide is not an approved prescription medication for obesity or diabetes as of September 2026, and it remains in clinical development. Roche reports that ENITH-1 and ENITH-2, two Phase 3 chronic weight-management studies, are underway, and that it plans a Phase 3 glycemic-control program and cardiovascular-outcomes studies beginning in the first half of 2027 (Roche, Sept. 22, 2026).
Because no approved product exists, items sold online under the names “CT-388” or “enicepatide” are not approved medicines. Clinical-trial supply is manufactured, dosed and monitored under controlled research conditions.
What happens next for enicepatide?
Phase 3 is the next stage. Larger trials should show how efficacy varies across populations, how tolerability and discontinuation rates hold up at scale, and whether the Phase 2 weight-loss trajectory persists. Cardiovascular-outcomes research will add evidence on cardiovascular events, kidney health and overall benefit–risk.
Enicepatide is also being developed in combination with the amylin analog petrelintide in the Phase 2 ZYNERGY program.
Frequently asked questions about enicepatide
Is enicepatide the same as CT-388?
Yes. CT-388 was the development code for the molecule now called enicepatide. Trial records may also use identifiers such as RO7795068 or RG6640, and Roche now generally uses enicepatide when discussing the late-stage program.
How much weight did people lose on enicepatide?
In the 48-week Phase 2 obesity trial, Roche reported 22.5% placebo-adjusted weight loss at 24 mg under the efficacy estimand (18.3% under the treatment-regimen estimand). Nearly 48% of participants at that dose lost at least 20% of body weight, and 26.1% lost at least 30%.
What are the side effects of CT-388?
The most commonly reported adverse events have been gastrointestinal. Early studies reported nausea, vomiting, diarrhea and decreased appetite, generally mild to moderate. Discontinuation because of adverse events was 5.9% (versus 1.3% for placebo) in the obesity trial and 2.0% (versus 0%) in the type 2 diabetes trial.
Is enicepatide better than tirzepatide?
That has not been established. Enicepatide produced strong Phase 2 results, but no randomized head-to-head trial with tirzepatide exists, and tirzepatide has far more Phase 3 and long-term evidence.
Is enicepatide a GLP-1 drug?
It is a GLP-1 receptor agonist and also a GIP receptor agonist. Describing it only as a “GLP-1 drug” omits the second target.
Is enicepatide FDA-approved?
No. As of September 2026, enicepatide is investigational. Roche is running Phase 3 weight-management studies and plans further late-stage research in diabetes and cardiovascular outcomes.
Is CT-388 the same type of drug as tirzepatide?
Both are dual GIP/GLP-1 receptor agonists. Enicepatide was designed with a distinct signaling profile involving limited beta-arrestin recruitment and receptor internalization. Whether this yields a clinical advantage has not been established.
When could enicepatide become available?
No approval or launch date has been confirmed. Phase 3 studies must produce sufficient efficacy and safety data, and regulators would then review any marketing application.
Summary
Enicepatide (CT-388) is an investigational GLP-1/GIP receptor agonist. A 48-week Phase 2 obesity study reported 22.5% placebo-adjusted weight loss at 24 mg under the efficacy estimand, and a separate Phase 2 study in type 2 diabetes reported 15.5% mean weight loss and a 2.65-percentage-point HbA1c reduction. Reported adverse events were mainly gastrointestinal. Enicepatide has a much smaller evidence base than tirzepatide, no head-to-head comparison exists, and Phase 3 studies are underway.
Sources
- Roche (Sept. 22, 2026): Positive Phase II results for enicepatide in people with type 2 diabetes and overweight or obesity. Diabetes results, safety and Phase 3 status.
- Roche (Jan. 27, 2026): Phase II obesity results for CT-388. Weight-loss, responder and discontinuation data.
- ClinicalTrials.gov NCT06525935: CT-388-103 and NCT06628362: CT-388-104. Study design and enrollment.
- ADA 2026 abstract: CT-388, a cAMP signal-biased GLP-1/GIP receptor agonist, 48-week Phase 2 study.
- ADA 2023 abstract: CT-388, a novel once-weekly dual GLP-1 and GIP receptor agonist. Phase 1 data.
- PubMed 41319798: CT-388 signaling and clinical study.
- NEJM: Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1).
- NEJM: Tirzepatide versus semaglutide once weekly in type 2 diabetes (SURPASS-2).
- FDA: FDA approves new medication for chronic weight management.