ARA-290 (Cibinetide)

1. Overview

ARA-290, known generically as cibinetide, is a synthetic 11-amino acid linear peptide (pyroglutamate-EELERALNSS) with a molecular weight of 1257 Da. It was engineered from the helix-B surface domain of erythropoietin (EPO) by Michael Brines and Anthony Cerami at Araim Pharmaceuticals, who identified the specific three-dimensional structure of EPO responsible for tissue-protective and anti-inflammatory signaling, independent of its hematopoietic (red blood cell-stimulating) activity [1][7][8].

The key innovation underlying ARA-290 is that native EPO has two distinct receptor interactions: one through the classical homodimeric EPO receptor (EPOR/EPOR) that drives erythropoiesis, and another through a heterodimeric complex termed the innate repair receptor (IRR), composed of the EPO receptor and the beta-common receptor (CD131). ARA-290 selectively activates the IRR without engaging the classical EPOR homodimer, thereby delivering tissue-protective, anti-inflammatory, and regenerative effects without the cardiovascular risks associated with increased red blood cell production [1][9].

ARA-290 has received both Orphan Drug Designation and Fast Track Designation from the U.S. FDA for the treatment of neuropathic pain in patients with sarcoidosis. It has also been granted EU Orphan Drug Designation for sarcoidosis. As of 2026, it remains in clinical development and has not received marketing approval in any jurisdiction.

Molecular Weight

1257 Da

Sequence

Pyr-Glu-Glu-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser (11 amino acids)

Half-life

~2 min (IV); ~20 min (subcutaneous)

Routes Studied

Intravenous, subcutaneous

Target

Innate Repair Receptor (EPOR/CD131 heterodimer)

Developer

Araim Pharmaceuticals

FDA Status

Not approved; Orphan Drug and Fast Track designations for sarcoidosis neuropathy

WADA Status

Not currently listed (non-erythropoietic)

2. Mechanism of Action

ARA-290 acts by selectively binding to and activating the innate repair receptor (IRR), a heterodimer of the erythropoietin receptor (EPOR) and the beta-common receptor (CD131, also known as CSF2RB). This receptor complex is a member of the type I cytokine receptor family and is expressed on a wide range of cell types including neurons, endothelial cells, immune cells, and Schwann cells [1][9].

Activation of the IRR by ARA-290 triggers several downstream pathways:

Anti-inflammatory signaling: ARA-290 antagonizes the production and effects of pro-inflammatory cytokines, particularly tumor necrosis factor-alpha (TNF-alpha), and reduces macrophage activation. This mirrors the paracrine tissue-protective function of locally produced hypoglycosylated EPO, which is released by many cell types as a stress response [1][9][13].

Nociceptive modulation: ARA-290 has been shown to antagonize the transient receptor potential vanilloid 1 (TRPV1) channel, providing a direct mechanism for pain relief beyond its anti-inflammatory effects. In preclinical models, it produced sustained reduction of allodynia coupled with suppression of the spinal microglia response, indicating it acts at multiple levels of the nociceptive pathway [10][11].

Nerve regeneration: The most clinically significant finding is that ARA-290 appears to stimulate regrowth of small nerve fibers from damaged axons. This has been demonstrated in human clinical trials through increases in corneal nerve fiber area (measured by confocal microscopy) and intraepidermal GAP-43-positive regenerating nerve fibers (measured by skin biopsy), suggesting a disease-modifying mechanism rather than mere symptomatic relief [3][6].

Cytoprotection: ARA-290 protects cells from apoptosis under conditions of inflammation, ischemia, and metabolic stress. This has been demonstrated in pancreatic islet transplantation models, retinal ischemia models, and doxorubicin-induced toxicity models [13][14][15][16].

Importantly, because ARA-290 does not bind the classical EPOR homodimer, it does not stimulate erythropoiesis and therefore does not carry the thromboembolic and cardiovascular risks associated with therapeutic EPO or erythropoiesis-stimulating agents [1][8].

3. Researched Applications

Sarcoidosis-Associated Small Fiber Neuropathy

Evidence level: Phase 2 clinical trials

Small fiber neuropathy (SFN) is a common and debilitating complication of sarcoidosis, causing burning neuropathic pain, autonomic dysfunction, and reduced quality of life. There are no approved disease-modifying therapies for sarcoidosis-associated SFN, making it an area of significant unmet medical need [4].

ARA-290 has been evaluated in three clinical studies for this indication. An initial randomized, double-blind pilot study (n=22) demonstrated safety and significant improvement in SFN screening list scores with intravenous ARA 290 (2 mg, 3x/week, 4 weeks) [2]. A subsequent open-label study showed increases in corneal nerve fiber density and improvements in pain, sensory thresholds, quality of life, and physical functioning [3]. The pivotal Phase 2b multicenter RCT (n=64) demonstrated that cibinetide 4 mg subcutaneously daily for 28 days significantly increased corneal nerve fiber area (P=0.012) and GAP-43-positive regenerating intraepidermal nerve fibers (P=0.035), providing objective evidence of nerve fiber regeneration [6].

Type 2 Diabetic Neuropathy

Evidence level: Phase 2 clinical trial

In a randomized Phase 2 study, ARA 290 (4 mg SC daily, 28 days) improved neuropathic symptoms as measured by the PainDetect questionnaire, increased corneal nerve fiber density, and additionally improved metabolic parameters including HbA1c and lipid profiles compared with placebo over a 56-day observation period. No safety concerns were identified [5].

Diabetic Macular Edema

Evidence level: Phase 2 open-label (exploratory)

A small Phase 2 study (n=9) evaluated cibinetide 4 mg SC daily for 12 weeks in patients with diabetic macular edema. The treatment was safe and some individual participants showed improvements in central retinal thickness, tear production, and visual function scores, though group-level improvement in best-corrected visual acuity was not achieved. The study was primarily designed to assess safety and generate preliminary efficacy signals [12].

Pancreatic Islet Transplantation

Evidence level: Preclinical

ARA-290 has shown protective effects on pancreatic islets in transplantation settings. It inhibited macrophage activation, prevented cytokine-induced islet damage and apoptosis, and improved islet engraftment outcomes in preclinical models, suggesting potential as an adjunctive therapy in islet transplantation protocols [13][14].

Cardioprotection and Multi-Organ Protection

Evidence level: Preclinical

In animal models, ARA-290 has been evaluated in myocardial infarction, chronic heart failure, traumatic brain injury, burn injury, and shock-induced multi-organ failure. In these diverse models, ARA-290 consistently prevented tissue injury, reduced inflammation, and activated healing processes, underscoring the broad protective role of the innate repair receptor pathway [7][9].

4. Clinical Evidence Summary

5. Dosing in Research

The following table summarizes doses used in published clinical studies. These are not therapeutic recommendations. ARA-290 (cibinetide) is not approved for human use, and optimal dosing has not been established through Phase 3 trials.

6. Safety and Side Effects

ARA-290 has demonstrated a favorable safety profile across all completed clinical studies. In formal preclinical animal toxicology studies, a good safety margin was observed with no organ damage or cytotoxicity at doses far exceeding therapeutic levels [9].

In human studies:

• Sarcoidosis trials: No potentially drug-related adverse events were reported. No abnormalities in laboratory or clinical assessments were observed [2][6].
• Type 2 diabetes trial: No potential safety issues were identified [5].
• Diabetic macular edema trial: No serious adverse events or anti-cibinetide antibodies were detected [12].
• Mild, transient injection site reactions and headaches have been reported at low frequency across studies.

A critical safety advantage of ARA-290 over erythropoietin is the absence of erythropoietic stimulation. Because ARA-290 does not increase red blood cell production, it avoids the thrombotic and cardiovascular risks (stroke, myocardial infarction, venous thromboembolism) that have been associated with EPO and erythropoiesis-stimulating agents [1][8].

Limitations and unknowns:

• Long-term safety data: The longest study duration has been 12 weeks. Chronic administration safety has not been evaluated in humans.
• Immune effects: While short-term immunomodulation appears beneficial, the consequences of sustained innate repair receptor activation on immune surveillance are unknown.
• Pregnancy and development: No reproductive or developmental safety data exist in humans.
• Drug interactions: Systematic evaluation of interactions with immunosuppressants, analgesics, or diabetes medications has not been conducted.
• Large-scale safety: The total number of patients treated in published trials remains small (approximately 100 across all studies), limiting the detection of rare adverse events.

7. Regulatory Status

United States (FDA): ARA-290 (cibinetide) is not approved for any therapeutic indication. It has received Orphan Drug Designation and Fast Track Designation from the FDA for the treatment of neuropathic pain in patients with sarcoidosis. Araim Pharmaceuticals completed an end-of-Phase 2 meeting with the FDA and has indicated plans for continued clinical development.

European Union: Cibinetide has been granted EU Orphan Drug Designation for the treatment of sarcoidosis. It is not approved as a medicinal product in any EU member state.

Development status: As of available information, ARA-290 has completed Phase 2 clinical development for sarcoidosis-associated small fiber neuropathy. No Phase 3 trial results have been publicly reported.

8. Related Peptides

See also: BPC-157 (Body Protection Compound-157), TB-500 (Thymosin Beta-4), GHK-Cu (Copper Peptide)

9. References

1. [1] Brines M, Cerami A. (2012). The receptor that tames the innate immune response. Molecular Medicine. DOI PubMed
2. [2] Heij L, Dahan A, Howal E, Brines M, Cerami A, et al. (2012). Safety and efficacy of ARA 290 in sarcoidosis patients with symptoms of small fiber neuropathy: a randomized, double-blind pilot study. Molecular Medicine. DOI PubMed
3. [3] Dahan A, Dunne A, Swartjes M, Proto PL, Heij L, Brines M, et al. (2013). ARA 290 improves symptoms in patients with sarcoidosis-associated small nerve fiber loss and increases corneal nerve fiber density. Molecular Medicine. DOI PubMed
4. [4] Dahan A, Brines M. (2014). ARA 290 for treatment of small fiber neuropathy in sarcoidosis. Expert Opinion on Investigational Drugs. DOI PubMed
5. [5] Brines M, Dunne AN, van Velzen M, Proto PL, Ostenson CG, Kirk RI, Petropoulos IN, Javed S, Malik RA, Cerami A, Dahan A. (2015). ARA 290, a nonerythropoietic peptide engineered from erythropoietin, improves metabolic control and neuropathic symptoms in patients with type 2 diabetes. Molecular Medicine. DOI PubMed
6. [6] Culver DA, Dahan A, Baber D, Cober D, Cerami A, Brines M, et al. (2017). Cibinetide improves corneal nerve fiber abundance in patients with sarcoidosis-associated small nerve fiber loss and neuropathic pain. Investigative Ophthalmology & Visual Science. DOI PubMed
7. [7] Brines M, Cerami A. (2008). Erythropoietin-mediated tissue protection: reducing collateral damage from the primary injury response. Journal of Internal Medicine. DOI PubMed
8. [8] Brines M, Patel NSA, Villa P, et al. (2008). Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin. Proceedings of the National Academy of Sciences. DOI PubMed
9. [9] Brines M, Cerami A. (2017). Targeting the innate repair receptor to treat neuropathy. Drug Design, Development and Therapy. DOI PubMed
10. [10] Swartjes M, Niesters M, Heij L, Dunne A, Cerami A, Brines M, Dahan A. (2014). ARA 290, a peptide derived from the tertiary structure of erythropoietin, produces long-term relief of neuropathic pain coupled with suppression of the spinal microglia response. Molecular Pain. DOI PubMed
11. [11] Dahan A, Brines M, Niesters M, Cerami A, van Velzen M. (2016). ARA 290 relieves pathophysiological pain by targeting TRPV1 channel: integration between immune system and nociception. Peptides. DOI PubMed
12. [12] Brines M, Tannemaat MR, de Graaf L, Cerami A, et al. (2020). A phase 2 clinical trial on the use of cibinetide for the treatment of diabetic macular edema. Journal of Clinical Medicine. DOI PubMed
13. [13] Montero-Melendez T, Boesen T, Brines M. (2016). A nonhematopoietic erythropoietin analogue, ARA 290, inhibits macrophage activation and prevents damage to transplanted islets. Transplantation. DOI PubMed
14. [14] Reid TJ, Dai Y, Bhatt DL, Brines M, et al. (2021). Cibinetide protects isolated human islets in a stressful environment and improves engraftment in the perspective of intra portal islet transplantation. PLoS ONE. PubMed
15. [15] El-Kordi A, Brines M, Bhatt S. (2020). An engineered non-erythropoietic erythropoietin-derived peptide, ARA290, attenuates doxorubicin induced genotoxicity and oxidative stress. Biomedicine & Pharmacotherapy. DOI PubMed
16. [16] Reid TJ, Kenyon NS. (2019). The vasoreparative potential of endothelial colony-forming cells in the ischemic retina is enhanced by cibinetide, a non-hematopoietic erythropoietin mimetic. Experimental Eye Research. PubMed