OPT101 Phase 1b in adults with type 1 diabetes
What this study tests
A completed, placebo-controlled Phase 1b study of the CD154-derived peptide OPT101 in 24 adults with T1D. Results posted 10 August 2026 show a small safety dataset and no C-peptide advantage over placebo.
Editorial review: .
Registry checked: 2026-09-17. Registry’s own update: 2026-08-10.
Most recent recorded citation date: 2026-08-10. Only explicit date metadata is included; an undated citation may be newer. This does not mean every claim was reviewed on that date.
Trial status, labels and access can change between reviews. How we review the evidence · How to read the evidence
Evidence at a glance
- Who can enter the study?
- Medically stable adults 18–60 with T1D diagnosed within the previous 20 years; people with clotting history, active infection, or immunomodulatory treatment were excluded. Registered eligibility ↗Enrollment criteria describe who may enter. They do not establish who was analyzed or the denominator for a reported result.
- Reported benefit and results
- Results posted 10 August 2026. 24 participants started (8 per arm); 18 completed. One treatment-related adverse event in each OPT101 dose group and none on placebo; no deaths. Posted end-of-study mixed-meal C-peptide means were 0.03 ng/mL (1.1 mg/kg), 0.07 ng/mL (2.8 mg/kg) and 0.16 ng/mL (placebo). That is not a C-peptide preservation signal. HbA1c change (mmol/mol) was also not better on drug. Do not treat completion, or the conference Th40 immunophenotyping abstract, as efficacy.Read the result sources and their limitations →
- Important harms
- Read the reported results, safety discussion and original sources. A separate harms summary is not available; this does not establish safety.
- Research access and approval
- Study regions: United States. A trial listing does not establish product approval or current recruitment at a particular site. Check the study’s current entry requirements.
- What remains uncertain?
- Read the full discussion and original sources for study limitations. Planned endpoints and completion dates are not results.
Research status alone does not establish approval, clinical benefit or local availability.
Primary endpoints
- Number of treatment-related adverse events (CTCAE v4.0) over 42 days
The full picture
This Phase 1b study asked whether repeated infusions of OPT101 are tolerable in adults with T1D and whether any early metabolic signal appears. The registry now has posted results. Safety looks acceptable in a tiny sample. The posted C-peptide and glucose tables do not support a claim that OPT101 preserves beta cells.
Sources
- [1]OPT101 in Type 1 Diabetes Patients · Trial registry · 2026-08-10