CT-388 Clinical Development Overview
CT-388's clinical program has progressed rapidly since Roche's $2.7 billion acquisition of Carmot Therapeutics in January 2024. The drug has demonstrated compelling efficacy in Phase 1/1b trials and is now in Phase 2, with Phase 3 planned for H1 2026.
| Phase | Status | Key Result |
|---|---|---|
| Phase 1 SAD/MAD | Complete | Up to 8% weight loss (4 weeks) |
| Phase 1b (Obesity) | Complete | 18.8% placebo-adj (24 weeks) |
| Phase 1 (T2D) | Complete | 3.0% HbA1c reduction (12 weeks) |
| Phase 2 (Obesity) | Enrolling | ~450 patients, 48 weeks |
| Phase 2 (T2D) | Enrolling | ~350 patients, 48 weeks |
| Phase 3 | Planned H1 2026 | Design TBD |
Phase 1 Dose-Finding Studies
Single-Ascending Dose (SAD)
Initial safety and pharmacokinetic studies with single doses ranging from 0.5 mg to 7.5 mg in healthy volunteers with obesity.
Multiple-Ascending Dose (MAD) — 4 Weeks[1]
| Dose | Weight Loss | Notes |
|---|---|---|
| 5 mg weekly | ~4.7% | Dose-dependent response |
| 8 mg weekly | ~6% | Dose-dependent response |
| 12 mg weekly | ~8% | Maximum tested in MAD |
- Half-life confirmed: ~6 days (135-151 hours) supporting once-weekly dosing
- Safety: Well-tolerated with expected GI adverse events
- Outcome: Supported advancement to Phase 1b with higher doses
Phase 1b Trial Results
The Phase 1b trial (NCT04838405) evaluated CT-388 at 8 mg and 22 mg doses in adults with obesity (BMI ≥30) or overweight with comorbidities over 24 weeks.[2]
22 mg Dose Results (Week 24)
| Endpoint | Result | Significance |
|---|---|---|
| Placebo-adjusted weight loss | 18.8% | p < 0.001 |
| ≥5% weight loss | 100% | All patients |
| ≥10% weight loss | 85% | 17/20 patients |
| ≥15% weight loss | 70% | 14/20 patients |
| ≥20% weight loss | 45% | 9/20 patients |
| Pre-diabetes resolution | 100% | All became normoglycemic |
22 mg Titration Schedule
The 22 mg dose was reached through gradual titration over approximately 8 weeks:
- Week 1-2: 5 mg weekly
- Week 3-4: 8 mg weekly
- Week 5-6: 12 mg weekly
- Week 7-8: 17 mg weekly
- Week 9+: 22 mg weekly (maintenance)
Remarkable Responder Rates
100% of patients achieved at least 5% weight loss—an unprecedented responder rate. This suggests CT-388 may offer more consistent efficacy across patients compared to current treatments where 20-30% are "non-responders."
Type 2 Diabetes Results
A 12-week cohort evaluated CT-388 22 mg in 19 adults with obesity and type 2 diabetes (14 CT-388, 5 placebo).[3]
Glycemic Control Results
| Endpoint | CT-388 | Placebo | Difference |
|---|---|---|---|
| HbA1c reduction | 3.0% | 0.2% | 2.8% (p<0.001) |
| HbA1c ≤6.5% | 100% | — | All patients |
| HbA1c <5.7% | 50% | — | 7/14 patients |
| Weight loss | 8.6% | 1.2% | 7.4% |
| ≥5% weight loss | 100% | — | All patients |
- Baseline HbA1c: 8.7% (CT-388) vs. 9.4% (placebo)
- Baseline weight: ~95-96 kg
- Discontinuations due to AEs: 0 (excellent tolerability)
- Background therapy: Diet/exercise alone or metformin
Diabetes Remission Potential
50% of CT-388 patients achieved HbA1c <5.7% (diabetes remission threshold) in just 12 weeks. This suggests CT-388 may have exceptional glycemic control potential in addition to weight loss.
Phase 2 Trials
NCT06525935 — Obesity Without T2D[4]
| Characteristic | Details |
|---|---|
| Target enrollment | ~450 participants |
| Duration | 48 weeks |
| Dose groups | 5 dose levels (levels 1-5) |
| Randomization | 80% CT-388, 20% placebo |
| Start date | August 2024 |
| Primary endpoint | Percent change in body weight |
| Results expected | Q1 2026 |
NCT06628362 — T2D + Obesity[5]
| Characteristic | Details |
|---|---|
| Target enrollment | ~350-400 participants |
| Duration | 48 weeks |
| Population | Overweight/obese with T2D |
| Randomization | 80% CT-388, 20% placebo |
| Primary endpoints | HbA1c and body weight |
| Results expected | Q1-Q2 2026 |
Phase 3 Plans
Roche announced Phase 3 initiation for H1 2026 at its Pharma Day investor event in September 2025. Full Phase 3 program details will be disclosed when Phase 2 data reads out.[6]
Expected Program Structure
- Multiple trials: Likely obesity, T2D, and potentially cardiovascular outcomes
- Large enrollment: Probably 2,000-5,000+ patients across trials
- Duration: 52-72 weeks for pivotal efficacy trials
- Comparator: Placebo-controlled; unlikely to have active comparator arm
Timeline refinement: Roche has stated it will "refine the guidance on timelines" when Phase 3 kicks off. Market entry is targeted for 2030.
How to Enroll in CT-388 Trials
CT-388 Phase 2 trials are currently enrolling. Unlike smaller biotechs, Roche/Genentech has extensive clinical trial infrastructure with sites globally.
Eligibility Criteria (General)
- NCT06525935 (Obesity): BMI ≥30 or ≥27 with weight-related comorbidities, adults 18-75
- NCT06628362 (T2D): Overweight/obese with type 2 diabetes, HbA1c 7.0-10.0%
- Exclusions: Prior bariatric surgery, GLP-1 medication use in past 3 months, significant cardiovascular disease
How to Apply
- Visit ClinicalTrials.gov and search "CT-388" or "NCT06525935"
- Check ForPatients.Roche.com for patient-friendly trial information
- Contact sites listed in the trial records
- Discuss eligibility with the research coordinator
Benefits of Trial Participation
- Free access to investigational medication before FDA approval
- Close medical monitoring at no cost
- Regular lab work and health assessments
- Contribute to scientific advancement
- Travel reimbursement typically provided
FAQs
In the current Phase 2 trials, randomization is 80:20 (drug:placebo), meaning there's an 80% chance of receiving active CT-388 and only 20% chance of placebo. This is more favorable than typical 50:50 randomization in some trials.
Phase 2 results are expected in Q1 2026. Since trials are 48 weeks long and started in mid-2024, top-line results should read out in early 2026, which will inform Phase 3 design.
CT-388's Phase 1b data (18.8% at 24 weeks) compares favorably to other pipeline drugs:
- Retatrutide (Lilly): ~24% at 48 weeks (Phase 2)
- CagriSema (Novo): ~25% at 68 weeks (Phase 3)
- VK2735 (Viking): ~14.7% at 13 weeks (Phase 2)
Direct comparison is difficult due to different trial durations. CT-388's 18.8% at 24 weeks suggests competitive efficacy trajectory.
Sources & References
- Steinberg A, et al. "CT-388, a Novel Once-Weekly Dual GLP-1 and GIP Receptor Modulator, Is Safe, Well-Tolerated, and Produces More than 8% Weight Loss in Four Weeks." Diabetes 2023;72(Supplement_1):75-LB. https://diabetesjournals.org/diabetes/article-abstract/72/Supplement_1/75-LB/149193
- Roche. "Roche reports positive Phase Ib results for its dual GLP-1/GIP receptor agonist CT-388 in people with obesity." May 16, 2024. https://www.roche.com/media/releases/med-cor-2024-05-16
- Steinberg A, et al. "Glycemic Control, Weight Reduction, and Safety with CT-388—Results from a 12-Week Cohort in Adults with Obesity and Type 2 Diabetes." Diabetes 2025;74(Supplement_1):763-P. https://diabetesjournals.org/diabetes/article/74/Supplement_1/763-P/160045/
- ClinicalTrials.gov. NCT06525935 - A Study of CT-388 in Participants With Obesity or Overweight. https://clinicaltrials.gov/study/NCT06525935
- ClinicalTrials.gov. NCT06628362 - A Study of CT-388 in Participants Who Are Overweight or Obese With Type 2 Diabetes Mellitus. https://clinicaltrials.gov/study/NCT06628362
- FierceBiotech. "Roche unveils strategy to become 'top 3' obesity company." September 2025. https://www.fiercebiotech.com/biotech/we-have-will-roche-unveils-strategy-become-top-3-obesity-company
Last updated October 6, 2026
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