OPT101 (CD40-pathway peptide)
Op-T LLC
What it is
A short CD154-derived peptide designed to restrain pathogenic CD40 signalling with the aim of avoiding broad immunosuppression. A 24-person Phase 1b study in people with established T1D posted results in August 2026: the peptide looked tolerable over the short posted follow-up, but the posted C-peptide and glucose numbers do not show a treatment benefit over placebo. A subcutaneous Phase 2 (NCT06964087) is listed as recruiting; it is not an efficacy result.
Editorial review: .
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 behind this assessment
Key evidence notes. Study results, product eligibility and access answer different questions.
- Who was studied?
- Study populations and analysis groups vary. Product age limits alone do not describe who was studied.See the linked studies and their populations →
- Benefit or performance
- Beta-cell preservation: Posted Phase 1b C-peptide values after a mixed-meal test were not higher on OPT101 than placebo (mean 0.03–0.07 ng/mL vs 0.16 ng/mL on placebo). That is not evidence of beta-cell preservation.[1]
- Important harms and treatment burden
- Safety: Primary outcome: one treatment-related adverse event in each OPT101 dose group and none on placebo over the 42-day posted follow-up; no deaths and no serious events reported in the posted tables. Earlier anti-CD154 antibodies were reported to cause clotting problems, so thromboembolism remains a class watch-out even though this peptide's posted safety table is small and short.[1]
- Approval and country access
- Country-specific approval and access are not summarized in this record.Approval, trial recruitment, local supply and funding are separate. Check the cited label or access source.
- Follow-up and remaining uncertainty
- Durability: Follow-up in the posted study was measured in weeks, not years, and no lasting C-peptide advantage was shown.[1]
Research status alone does not establish approval, clinical benefit or local availability. This record cites company or conference reports. Those sources may describe interim findings; their source type is shown in the source list.
Editorial score: calculation and evidence
A weighted editorial judgment on a 0–100 scale, not a probability of success or a measured treatment effect. Higher criterion scores mean more favorable assessments.
Default calculation: 18 × 30 + 12 × 20 + 48 × 20 + 22 × 10 + 28 × 20 = 2520; divide by total weight 100. Unrounded weighted result: 25.2.
Posted Phase 1b C-peptide values after a mixed-meal test were not higher on OPT101 than placebo (mean 0.03–0.07 ng/mL vs 0.16 ng/mL on placebo). That is not evidence of beta-cell preservation.[1]
Follow-up in the posted study was measured in weeks, not years, and no lasting C-peptide advantage was shown.[1]
Primary outcome: one treatment-related adverse event in each OPT101 dose group and none on placebo over the 42-day posted follow-up; no deaths and no serious events reported in the posted tables. Earlier anti-CD154 antibodies were reported to cause clotting problems, so thromboembolism remains a class watch-out even though this peptide's posted safety table is small and short.[1]
Phase 1b enrolled medically stable adults 18–60 with T1D diagnosed within 20 years, not newly diagnosed children or stage 1–2 relatives.[1]
Human Phase 1b completed with posted results (n=24 started; 18 completed). A subcutaneous Phase 2 is listed as recruiting (NCT06964087, estimated n=72). That is still not a Phase 2/3 efficacy package.[2]
The full picture
OPT101 is described as a 15-amino-acid peptide derived from CD154 (CD40 ligand). The idea is to quiet the CD40 pathway that helps drive autoimmune T cells, with the aim of avoiding the clotting problems reported with earlier anti-CD154 monoclonal antibodies.
A randomized, placebo-controlled Phase 1b study (NCT05428943) enrolled 24 adults with T1D and posted results on 10 August 2026. Eight people were assigned to 1.1 mg/kg, eight to 2.8 mg/kg, and eight to placebo; six in each group completed. The primary endpoint was treatment-related adverse events over 42 days: one event in each active-dose group and none on placebo, with no deaths. Posted mixed-meal C-peptide means were not higher on drug than placebo, so this record is scored as an early safety programme, not as a therapy that has been shown to preserve insulin production.
A conference immunophenotyping abstract reported lower pathogenic Th40 cells and higher Tregs. That is a mechanistic signal from a meeting abstract, not a clinical efficacy result.
A subcutaneous Phase 2 (NCT06964087) is recruiting in the US (estimated n=72; started 10 April 2026). It is a pharmacokinetic and pilot C-peptide study, not a posted preservation result.
Coming soon
ETA · Phase 1b complete with posted results; subcutaneous Phase 2 listed as recruiting (NCT06964087). No Phase 3 and no approval path.
Sources
- [1]OPT101 in Type 1 Diabetes Patients · Trial registry · 2026-08-10 — Phase 1b completed; results first posted 10 August 2026. Actual enrollment 24; primary completion 21 February 2024.
- [2]Pharmacokinetic and Early Efficacy of OPT101 in Patients With Type 1 Diabetes Mellitus · Trial registry · 2026-04-06 — Phase 2 recruiting; estimated n=72; last update 6 April 2026. No results.
- [3]Restoring Immune Homeostasis with a Novel Peptide — Phase 1b immunophenotyping · Conference finding · 2026-01-01 — Conference immunophenotyping abstract; not a substitute for the posted registry efficacy tables.