RPB

Antigen-specific peptide immunotherapy

proinsulin peptide C19-A3 (MonoPepT1De), MultiPepT1De (multiple islet peptide administration), ATX-MS-1467 (four myelin basic protein peptides), MBP peptides; related: Diamyd/GAD65-alum (a protein, not a peptide), IMCY-0098, NBI-6024, altered peptide ligands

Immune & bioregulators
Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates
Note on this profile. These are investigational immunotherapies given by injection inside clinical trials under specialist supervision. None is approved, none is available outside trials, and nothing here describes self-preparation. Nothing on this page is a reason for anyone to alter insulin or disease-modifying therapy.

1What it is

Both type 1 diabetes and multiple sclerosis are diseases in which T cells attack a known, specific tissue target — insulin-producing beta cells in the first case, the myelin sheath in the second. Every approved immunotherapy for these conditions works by suppressing or depleting broad parts of the immune system, with the infection and malignancy risks that follow. Antigen-specific peptide immunotherapy is the attempt to do something fundamentally different: give the exact epitope that the autoreactive T cells recognise, in a way that re-establishes tolerance to it, and leave everything else alone.

This is the same tolerance-induction logic as peptide allergen immunotherapy (profile 239), applied to autoimmunity. The attraction is obvious and the evidence is early. Two programmes are far enough along to describe honestly: the proinsulin peptide work in type 1 diabetes, and ATX-MS-1467 in multiple sclerosis.

Note that the better-known GAD65-alum product (Diamyd) is a whole recombinant protein with an aluminium adjuvant, not a peptide, and sits outside this profile — it is mentioned because its mixed phase 2 and phase 3 history is part of the same story of antigen-specific therapy in type 1 diabetes.

2How it's thought to work

A short autoantigen peptide injected intradermally without adjuvant is presented on MHC class II in the absence of a danger signal.
Autoreactive CD4+ T cells encountering their epitope under these conditions are driven toward anergy, deletion or a regulatory phenotype rather than effector function.
Induced IL-10-producing regulatory T cells suppress responses locally, including to other epitopes of the same tissue (linked suppression) — important, because by the time either disease is diagnosed the autoimmune response has spread well beyond the first epitope.
In type 1 diabetes, the hoped-for clinical consequence is preservation of residual beta-cell function, measured by C-peptide, in people recently diagnosed.
In multiple sclerosis, it is reduced inflammatory activity, measured by new gadolinium-enhancing lesions on MRI.
Dose and schedule are critical and double-edged: in animal models the wrong dose or frequency of the same peptide can expand effector T cells and make disease worse. This is not a theoretical concern — it is the central safety question for the whole approach.
The general form: a defined peptide shown to the immune system on purpose, to provoke a response against it or — at other doses and schedules — to teach tolerance to it.Schematic — not to scale

3What the research shows

Type 1 diabetes, proinsulin peptide (MonoPepT1De)

A randomised, placebo-controlled phase 1b study in 27 adults within 100 days of type 1 diabetes diagnosis gave 10 µg of the proinsulin C19-A3 peptide intradermally every 2 or 4 weeks for 6 months. It was safe, with no acceleration of beta-cell loss. Stimulated C-peptide was maintained in treated participants over 12 months while it declined in the placebo group, and placebo participants required increasing insulin doses while treated participants did not. Immunological markers shifted toward a regulatory profile (Alhadj Ali 2017, Science Translational Medicine). This is a 27-person phase 1b whose primary purpose was safety; the C-peptide finding is encouraging and must not be reported as efficacy. [1]

Type 1 diabetes, multiple islet peptides (MultiPepT1De)

A phase 1b study extended the approach to a pool of six peptides from proinsulin, GAD65, IA-2 and IGRP, on the reasoning that targeting several epitopes better matches the spread of the real autoimmune response. It was reported as safe and feasible in a small cohort, with no evidence of disease acceleration. Safety and feasibility only; no efficacy claim (Alhadj Ali / Dayan group, King's College London).
Graded B / A (negative)

Type 1 diabetes, other peptide constructs

NBI-6024, an altered peptide ligand of the insulin B9-23 epitope, did not preserve C-peptide in a randomised trial. IMCY-0098, a proinsulin-derived "Imotope", has reported early-phase safety and immune data. No antigen-specific therapy of any kind has yet shown a definitive phase 3 benefit in type 1 diabetes; the only approved disease-modifying immunotherapy in the condition is teplizumab, an anti-CD3 antibody, which is broad rather than antigen-specific.

Multiple sclerosis, ATX-MS-1467

This is a mixture of four peptides from myelin basic protein, selected as the epitopes recognised by autoreactive T cells in HLA-DR-restricted contexts. An open-label phase 2a study in relapsing MS used intradermal dose escalation then maintenance and reported a reduction in new gadolinium-enhancing MRI lesions compared with each patient's own pre-treatment , with good tolerability (Chataway 2018, Neurology). The critical limitation is that this was open-label and compared against patients' own baselines rather than a placebo arm, in a disease with marked spontaneous variation in MRI activity — so the apparent effect cannot be separated from regression to the mean. The programme did not advance to a positive randomised trial and the original licensor returned rights †. [2]
Graded B (reasonably solid)

Mechanistic human work

Across both diseases, trials have reproducibly demonstrated the intended immunological changes: induction of IL-10-producing antigen-specific regulatory T cells, reduced interferon-gamma responses to the target antigen, and in the diabetes work a shift in the IL-10:interferon-gamma ratio. As with allergen peptide therapy, the immunology is more convincing than the clinical evidence.
Not graded

What has not been shown — stated plainly

No peptide antigen-specific immunotherapy has shown benefit in a positive, adequately powered, randomised, placebo-controlled phase 3 trial in either type 1 diabetes or multiple sclerosis. All the clinical evidence above comes from studies of between about 20 and 40 participants, several of them open-label.

4Reported side effects and interactions

Literature-reported

the dominant reported events are local — injection-site erythema, pruritus and induration, usually mild. Systemic events were uncommon and generally mild in the published cohorts. Crucially, the thing these trials were designed to detect — acceleration of the underlying autoimmune disease — was not observed: no excess beta-cell loss in the diabetes studies and no increase in relapse or MRI activity attributable to treatment in the MS work. Numbers are small and follow-up short, so "not observed" is not "excluded".

Community-reported

Community use: essentially none documented. These are trial-only products.

Theoretical. the central theoretical risk is the one from animal models — that peptide administration at the wrong dose or schedule expands effector rather than regulatory T cells and worsens disease. Hypersensitivity to the administered peptide and, in the MS context, induction of encephalitogenic responses are also theoretical concerns that have driven conservative dose escalation.

Interactions. concurrent immunosuppressive or immunomodulatory disease-modifying therapy would be expected to alter the tolerance mechanism and was generally excluded or controlled in these trials. In type 1 diabetes, insulin requirements and glycaemic control are the clinical context and were tracked; nothing in this profile is a reason to change insulin therapy.

Markers researchers commonly monitor

From trial protocols:

MarkerWhy it's watched
Stimulated and fasting C-peptide (mixed-meal tolerance test)the standard measure of residual beta-cell function and the primary efficacy marker in type 1 diabetes immunotherapy trials. Preservation of C-peptide, not HbA1c, is what these trials are built around.
HbA1c, insulin dose per kg per day, and insulin-dose-adjusted HbA1c (IDAA1c)clinical glycaemic context; insulin requirement is a practical signal of beta-cell preservation.
Islet autoantibodies (GAD, IA-2, ZnT8, insulin)disease characterisation, not a treatment response marker.
HLA class II genotype (DR4/DQ8 and related)epitope presentation depends on it; an eligibility criterion in the peptide work.
Antigen-specific T-cell cytokine profile, particularly the IL-10 to interferon-gamma ratio, and regulatory T-cell frequencythe mechanistic readout of whether tolerance was induced.
New and enlarging gadolinium-enhancing T2 lesions on MRIthe primary activity marker in the MS work, and the measure whose spontaneous variability makes open-label results hard to interpret.
Relapse rate and EDSS (Expanded Disability Status Scale)clinical MS endpoints.
Injection-site assessment, including delayed reactionsthe main observed adverse event in both programmes.
CBC, CMP and standard safety labsroutine monitoring; neither programme reported systemic laboratory toxicity.

Free for everyone. Safety information is never behind a paywall.

5Formulation and administration context

Supplied as a refrigerated, adjuvant-free aqueous peptide solution prepared by trial pharmacy and given as a small-volume intradermal injection by clinic staff, on a strictly specified schedule — every two or four weeks for six months in the diabetes studies, and a carefully escalated then maintained schedule in the MS study. The absence of adjuvant is deliberate: adding a danger signal would be expected to immunise rather than tolerise, which is the opposite of the intent. Dose and interval are not incidental details but the main determinants of whether tolerance or sensitisation results, which is why no dose here should be read as transferable to any other context. There is no self-prepared or compounded version of these products and no dose calculation appropriate to publish.

6Commonly studied alongside

In type 1 diabetes: insulin therapy (standard care throughout), teplizumab and other broad immunotherapies as comparators in the wider field, GAD65-alum (a protein antigen therapy). In multiple sclerosis: approved disease-modifying therapies as the standard of care and comparator context. Conceptually related: peptide allergen immunotherapy (profile 239) — the same tolerance-induction mechanism in allergy.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

RegionStatus (checked —)
United StatesNot FDA-approved; investigational in both indications
European UnionNot authorised
United KingdomNot licensed. The main type 1 diabetes peptide programme is UK academic work †
AustraliaNot approved
South AfricaNot registered with SAHPRA
SportNot listed by WADA; no performance application

8Open questions

  • Can a single epitope, or even a pool of six, control an autoimmune response that has already spread across many epitopes by the time of diagnosis?
  • What dose and interval induce tolerance rather than sensitisation in humans? Animal models show both outcomes from the same peptide, and human dose-finding is still early.
  • Does the approach need to be applied before clinical onset — in antibody-positive but normoglycaemic individuals — to work at all?
  • Will any of these programmes reach a randomised phase 3, or will antigen-specific tolerance in autoimmunity move to cell-based and nanoparticle delivery instead?

9References

  1. 1Alhadj Ali M et al. (2017). Metabolic and immune effects of immunotherapy with proinsulin peptide in human new-onset type 1 diabetes. Science Translational Medicine. DOI
  2. 2Chataway J et al. (2018). Effects of ATX-MS-1467 immunotherapy over 16 weeks in relapsing multiple sclerosis. Neurology. PubMed · DOI
  3. 3Streeter HB et al. (2015). Preclinical development and first-in-human study of ATX-MS-1467 for immunotherapy of MS. Neurology: Neuroimmunology & Neuroinflammation. PubMed · DOI
  4. 4Thrower SL et al. (2009). Proinsulin peptide immunotherapy in type 1 diabetes: report of a first-in-man phase I safety study. Clinical and Experimental Immunology. PubMed · DOI
  5. 5Dayan CM et al. (2019). Changing the landscape for type 1 diabetes: the first step to prevention. Lancet. PubMed · DOI
  6. 6Larché M, Wraith DC (2005). Peptide-based therapeutic vaccines for allergic and autoimmune diseases. Nature Medicine. PubMed · DOI
  7. 7ClinicalTrials.gov. NCT02620332 (MultiPepT1De) and NCT01973491 (ATX-MS-1467) trial records. PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

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11Page history

31 Oct 2026Profile published — awaiting medical review

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