Small-nerve-fiber imaging
Short Phase 2 studies used corneal and skin imaging to look for structural nerve-fiber changes alongside symptoms and physical function.
P—20 • Innate repair signaling profile
ARA-290(Also known as cibinetide)
An 11-amino-acid erythropoietin-derived research peptide with early human evidence in small-nerve-fiber biology and expanding preclinical work in tissue-stress signaling.
Name
ARA-290
Also known as cibinetide, pHBSP, or pyroglutamate helix B surface peptide
- Scientific classification
- Synthetic 11-amino-acid peptide modeled on the tissue-protective surface of erythropoietin
- Library family
- Regenerative
- Regulatory status
- Investigational and not FDA approved; FDA lists cibinetide among 503A bulk substances nominated without adequate support
Compound overview
A compact erythropoietin-derived signal designed to study repair without driving red-blood-cell production.
ARA-290, also called cibinetide, was engineered from the helix B surface of erythropoietin. The design goal was to retain selected tissue-response signals associated with erythropoietin while avoiding the conventional pathway that stimulates red-blood-cell production.
The most developed human research involves small-nerve-fiber loss. Short randomized Phase 2 studies in people with sarcoidosis-associated neuropathy reported encouraging changes in corneal or skin nerve-fiber measurements and selected symptom or function measures. A Phase 2b trial of 64 participants found its clearest structural signal at one studied dose, while pain improved across all groups and did not show a clear overall advantage over placebo.
A separate early study in people with type 2 diabetes and painful neuropathy reported changes in corneal nerve-fiber density, neuropathic symptoms, and selected metabolic measures. These findings are useful research signals, but the trials were small, short, and not designed to establish routine clinical use.
More recent research is broadening the biological questions. A 2025 mouse and cell study connected ARA-290 with SIRT1, NF-κB, and IL-1β signaling in an experimental dental-inflammation model. A 2026 review also discussed cibinetide among erythropoietin derivatives being explored for time-sensitive neuroprotection after traumatic brain injury.
ARA-290 has not progressed to an established Phase 3 evidence base or regulatory approval. Larger independent trials are needed to confirm safety, determine whether imaging changes lead to durable improvements people can feel, and clarify which conditions—if any—may benefit.
Inflammatory-pathway research
A mouse and cell study linked ARA-290 with SIRT1, NF-κB, and IL-1β signaling in an experimental model of inflammation and local bone loss.
Timing tissue protection
A 2026 review placed cibinetide within a broader effort to match protective signaling compounds to different stages of traumatic brain injury.
Mechanism under study
Innate repair and stress-response signaling
ARA-290 is designed to engage a proposed tissue-protective receptor system without strongly activating erythropoietin's red-blood-cell pathway. The full mechanism and its relevance across human tissues remain under investigation.
Innate repair receptor
Research proposes signaling through a receptor complex involving the erythropoietin receptor and CD131 in stressed or injured tissue.
Small-nerve-fiber response
Human studies have used corneal microscopy and skin markers to examine whether short-term exposure is associated with structural nerve-fiber changes.
Inflammatory signaling
A 2025 preclinical study connected ARA-290 with SIRT1 activity and lower NF-κB and IL-1β signaling in a specific inflammation model.
Receptor models and short-term biomarker changes do not establish nerve repair, pain relief, tissue healing, or clinical effectiveness in people.
Current research areas
Questions under investigation
- How small nerve fibers respond to injury and inflammation
- Whether corneal imaging can track nerve recovery
- How stressed tissues switch on protective signals
- How inflammation and local repair signals interact
- Whether early trial findings hold up in larger human studies
Evidence summary
Early human signals with a clear need for confirmation
- Human nerve-fiber research: Randomized Phase 2 studies reported encouraging changes in selected corneal and skin nerve-fiber measurements.
- Symptom research: Early trials explored neuropathic symptoms, physical function, and quality of life, with mixed results that require larger confirmation.
- Nonerythropoietic design: The peptide offers a way to study selected erythropoietin-related tissue signals without intentionally stimulating red-blood-cell production.
- Inflammatory-pathway research: Newer laboratory work is examining how ARA-290 influences macrophages, inflammatory signals, and local tissue stress.
- Neuroprotection framework: Recent reviews identify cibinetide as one candidate for studying how timing and injury stage may shape protective signaling.
ARA-290 has more human research than many experimental peptides, but the studies remain small and short. They do not establish durable nerve regeneration, pain relief, tissue repair, or long-term safety.
Educational notice
Education, not usage guidance.
This profile is provided for scientific education only. It is not medical advice, neuropathy guidance, dosing information, or instructions for ARA-290 use. ARA-290 is investigational and not FDA approved. FDA's 503A nomination list places cibinetide in Category 3, meaning the nomination lacked adequate support for evaluation. Research-market materials should not be assumed to match the identity, purity, or properties of substances used in published clinical studies.
Key scientific referencesComing soon
A curated primary-source reference list will be added during the next educational expansion.