What is ARA-290? The Innate Repair Receptor Peptide Explained
A research guide to ARA-290 (cibinetide) — the non-erythropoietic erythropoietin derivative studied for tissue-protective and neuroregenerative research applications.
ARA-290 — also known as cibinetide — is an 11-amino acid synthetic peptide derived from the structural “helix B” surface region of erythropoietin (EPO). It was engineered to retain the tissue-protective signalling properties of EPO while eliminating its haematopoietic activity, making it a key research tool for studying the biology of the innate repair receptor (IRR) independently of red blood cell production.
What Makes ARA-290 Unique?
Native EPO acts through two distinct receptor systems: the classical homodimeric EPO receptor (EPOR)2, which drives erythropoiesis, and the innate repair receptor — a heteromeric complex of EPOR and the beta-common receptor (CD131) — which mediates tissue-protective, anti-inflammatory and regenerative signalling. ARA-290 is selective for the innate repair receptor and does not meaningfully engage the classical EPOR pathway, so it is studied without the erythropoietic effects associated with EPO itself.
This receptor selectivity makes ARA-290 a widely referenced tool compound for isolating and studying innate repair receptor biology in inflammation, small-fibre nerve injury and tissue-protection research.
Mechanism of Action
ARA-290’s activity centres on selective innate repair receptor activation, with downstream effects on inflammatory signalling and cellular survival pathways.
- Innate Repair Receptor Binding: ARA-290 binds the EPOR/CD131 heteromer, triggering cytoprotective intracellular signalling distinct from erythropoietic EPOR homodimer activation.
- Anti-Inflammatory Signalling: Research models show modulation of pro-inflammatory cytokine pathways (including NF-κB-associated signalling), relevant to models of chronic low-grade inflammation.
- Cytoprotective Effects: Activation of the innate repair receptor is studied for its role in reducing apoptosis in stressed or injured cells, particularly in neuronal and vascular tissue models.
- Small-Fibre Nerve Signalling: ARA-290 has been studied for effects on small-diameter nerve fibre density and function in models of peripheral neuropathy.
Key Research Areas
Neuropathic Pain and Small-Fibre Neuropathy Research: ARA-290 is one of the most extensively studied innate repair receptor agonists in models of small-fibre neuropathy, including sarcoidosis-associated and diabetic neuropathy research contexts.
Corneal Nerve Regeneration: Studies have examined ARA-290’s effects on corneal nerve fibre density and regeneration, given the cornea’s reliance on small-fibre innervation.
Metabolic and Inflammatory Research: ARA-290 has been investigated in models of insulin resistance and chronic inflammation, exploring the intersection of innate repair receptor signalling with metabolic regulation.
Tissue-Protection and Ischaemic Injury Models: As a non-erythropoietic tool for studying EPO-pathway tissue protection, ARA-290 is referenced in ischaemia-reperfusion and vascular injury research without the confounding haematopoietic effects of native EPO.
Compound Profile
| Property | Detail |
|---|---|
| Sequence | pGlu-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser (11 residues, modelled on helix B of erythropoietin) |
| Molecular formula | C51H84N16O21 |
| Molecular weight | 1257.3 g/mol |
| CAS number | 1208243-50-8 |
| Other names | Cibinetide (INN); helix B surface peptide analogue |
| Target | Innate repair receptor (EPOR/CD131 heteromer); no meaningful erythropoietic activity reported |
| Regulatory status | Investigational — phase 2 trials completed; not approved in any market |
Key Published Research
- Rational design (2008): Peptides built from the helix B surface of EPO were tissue-protective in rodent injury models without stimulating red blood cell production — the basis for ARA-290.1
- Sarcoidosis pilot (2012): In a small randomised, double-blind pilot in sarcoidosis patients with small-fibre neuropathy symptoms, ARA-290 improved neuropathic symptom scores versus placebo and was well tolerated.2
- Corneal nerve fibres (2013): A 28-day trial in sarcoidosis-associated small-fibre loss reported improved symptoms and increased corneal nerve fibre density.3
- Type 2 diabetes (2015): In patients with type 2 diabetes and painful neuropathy, ARA-290 improved HbA1c and neuropathic symptoms over 28 days compared with placebo.4
- Phase 2b (2017): Cibinetide increased corneal nerve fibre abundance versus placebo in patients with sarcoidosis-associated small-fibre loss and neuropathic pain.5
Research Status (2026)
ARA-290 remains investigational. The published clinical programme consists of small phase 2 studies lasting weeks rather than months, and no phase 3 results have been reported. It continues to be used as a tool compound for separating the tissue-protective actions of the EPO pathway from its effects on red blood cell production.
Evidence Quality & Limitations
Human trials have been small and short, and several relied on surrogate endpoints such as corneal nerve fibre metrics and symptom questionnaires. Most trials were run by the developer and its academic collaborators. The exact composition and signalling of the innate repair receptor are still being characterised, so mechanistic conclusions should be drawn cautiously.
References
- Brines M, et al. Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin. Proc Natl Acad Sci USA. 2008;105:10925–30. PubMed
- Heij L, et al. Safety and efficacy of ARA 290 in sarcoidosis patients with symptoms of small fiber neuropathy: a randomized, double-blind pilot study. Mol Med. 2012;18:1430–6. PubMed
- Dahan A, et al. ARA 290 improves symptoms in patients with sarcoidosis-associated small nerve fiber loss and increases corneal nerve fiber density. Mol Med. 2013;19:334–45. PubMed
- Brines M, et al. ARA 290, a nonerythropoietic peptide engineered from erythropoietin, improves metabolic control and neuropathic symptoms in patients with type 2 diabetes. Mol Med. 2015;20:658–66. PubMed
- Culver DA, et al. Cibinetide improves corneal nerve fiber abundance in patients with sarcoidosis-associated small nerve fiber loss and neuropathic pain. Invest Ophthalmol Vis Sci. 2017;58:BIO52–60. PubMed
