ARA-290

ARA-290, also known as cibinetide or pyroglutamate helix B surface peptide (pHBSP), is an 11-amino-acid peptide designed from the structure of erythropoietin (EPO) Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin. It activates the innate repair receptor (IRR), a proposed pairing of the EPO receptor and the beta common receptor (CD131), to shift signaling toward tissue protection and inflammation control without stimulating red blood cell production Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin+1. Phase 2 studies have tested cibinetide in diabetic macular edema and sarcoidosis-associated small-fiber neuropathy A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema+1. Much of the broader evidence comes from animal models of nerve injury, wound healing, cardiac stress, and metabolic dysfunction Activation of the EPOR-β common receptor complex by cibinetide ameliorates impaired wound healing in mice with genetic diabetes+3.

ARA-290 binds the innate repair receptor (IRR), which is thought to pair the erythropoietin receptor (EPOR) with the beta common receptor (CD131) Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin. This receptor is not present at high levels in healthy tissue, but it rises after injury, inflammation, or metabolic stress Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin. Binding shifts signaling away from the EPOR homodimer pathway that drives red blood cell production and toward PI3K/Akt and suppression of NF-kB, a key inflammatory switch Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin+1.

Downstream, ARA-290 reduces reactive oxygen species and blocks NLRP3 inflammasome activation in nerve-supporting Schwann cells after sciatic nerve injury ARA290, an alternative of erythropoietin, inhibits activation of NLRP3 inflammasome in schwann cells after sciatic nerve injury. In an apical periodontitis model, it increased SIRT1 and reduced acetylated NF-kB and IL-1 beta, supporting an anti-inflammatory axis ARA290 Attenuates Apical Periodontitis via SIRT1/NF-κB/IL-1β Pathway Modulation. The plasma half-life is roughly 2 minutes, but the downstream tissue-protective signaling lasts much longer Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin. Pharmacokinetic and receptor details are still debated; one study did not find a direct physical EPOR-beta common receptor interaction EPO does not promote interaction between the erythropoietin and beta-common receptors.

Secondary mechanisms

• Antioxidant/anti-inflammatory: lowers ROS, TNF-alpha, IL-1 beta, and IL-6 while raising glutathione and antioxidant enzymes in neuronal cells Mechanisms of ARA290 in counteracting cadmium-triggered neurotoxicity in PC12 cells.
• Macrophage polarization: shifts macrophages toward an M2 repair phenotype and reduces inflammatory damage; inhibits macrophage activation to protect transplanted islets Cibinetide dampens innate immune cell functions thus ameliorating the course of experimental colitis+1.
• Endothelial repair: improves circulating endothelial progenitor cell angiogenic potential and homing ARA290, a Specific Agonist of Erythropoietin/CD131 Heteroreceptor, Improves Circulating Endothelial Progenitors' Angiogenic Potential and Homing Ability.
• Pain modulation: interacts with TRPV1 channels to reduce pathological pain ARA 290 relieves pathophysiological pain by targeting TRPV1 channel: Integration between immune system and nociception.

Human evidence is strongest for small-fiber neuropathy and neuropathic pain. In patients with sarcoidosis-associated small-fiber nerve loss, cibinetide improved corneal nerve fiber abundance and neuropathic pain Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain. Corneal nerve fiber size metrics have been proposed as treatment-response biomarkers in small fiber neuropathy Corneal nerve fiber size adds utility to the diagnosis and assessment of therapeutic response in patients with small fiber neuropathy. A phase 2 trial evaluated cibinetide for diabetic macular edema A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema.

Preclinical models show broader tissue-protective effects:

• Peripheral nerve repair: reduced NLRP3 inflammasome activation and improved functional recovery after sciatic nerve injury ARA290, an alternative of erythropoietin, inhibits activation of NLRP3 inflammasome in schwann cells after sciatic nerve injury; reviewed as a promising nerve repair peptide The protective effect of erythropoietin and its novel derived peptides in peripheral nerve injury.
• Wound healing: improved diabetic wound healing via EPOR-beta common receptor activation Activation of the EPOR-β common receptor complex by cibinetide ameliorates impaired wound healing in mice with genetic diabetes; elastin co-delivery accelerated diabetic wound healing Co-delivery of a growth factor and a tissue-protective molecule using elastin biopolymers accelerates wound healing in diabetic mice.
• Cardiac and vascular: reduced age-related cardiac inflammation and decline, improved healthspan in mice A small erythropoietin derived non-hematopoietic peptide reduces cardiac inflammation, attenuates age associated declines in heart function and prolongs healthspan; improved endothelial progenitor angiogenic potential ARA290, a Specific Agonist of Erythropoietin/CD131 Heteroreceptor, Improves Circulating Endothelial Progenitors' Angiogenic Potential and Homing Ability.
• Metabolic: improved glucose tolerance and insulin sensitivity without raising red cells The Role of Erythropoietin in Metabolic Regulation+1.
• Inflammatory and renal: reduced colitis and renal allograft injury through anti-inflammatory pathways EPO Derivative ARA290 Attenuates Early Renal Allograft Injury in Rats by Targeting NF-κB Pathway+1.
• Bone: inhibited osteoclastogenesis and increased bone mineral density in mice The Non-Erythropoietic EPO Analogue Cibinetide Inhibits Osteoclastogenesis In Vitro and Increases Bone Mineral Density in Mice.

Published human protocols used cibinetide for finite courses. A 4 mg subcutaneously once daily for 28 days course is community protocol; the provided clinical abstract Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain did not report dose details. A phase 2 diabetic macular edema trial used repeated dosing, though the abstracted dose was not specified in the corpus A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema. Community protocols often extend the 4 mg once-daily schedule to 4-6 weeks, followed by 2-4 weeks off, and some practitioners use 3 times weekly as maintenance after an initial daily course (community protocol). Fixed dosing is more common than body-weight adjustment, though a weight-scaled approximation of about 0.06 mg/kg has been discussed for adults outside the reference range (community protocol). No oral route is used because the peptide has negligible oral bioavailability Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin.

ARA-290 is supplied as a lyophilized powder for reconstitution. Bacteriostatic water (0.9% benzyl alcohol) is the standard diluent, and sterile water for injection may be used for single-use vials (community protocol). Add the diluent slowly down the vial wall and swirl gently; do not shake or vortex (community protocol). For storage, keep unopened lyophilized vials refrigerated at 2-8°C, or at -20°C for long-term storage, protected from light and moisture (community protocol). After reconstitution, keep the solution refrigerated at 2-8°C and discard after 30 days. Do not freeze the reconstituted peptide, and avoid repeated freeze-thaw cycles (community protocol). ARA-290's peptide backbone can degrade under heat or protease exposure, so minimize room-temperature time and do not autoclave Functionalized Biopolymer Particles Enhance Performance of a Tissue-Protective Peptide under Proteolytic and Thermal Stress.

No formal drug-drug interaction trials for ARA-290 were identified. The following is based on mechanistic and preclinical observations.

• Immunosuppressants and corticosteroids: ARA-290 shifts macrophages toward an M2 anti-inflammatory phenotype and reduces NF-kB/NLRP3 signaling ARA290 Attenuates Apical Periodontitis via SIRT1/NF-κB/IL-1β Pathway Modulation+1. Theoretical additive immunosuppression; monitor for infection.
• Antihypertensives: ARA-290 improves endothelial nitric oxide signaling and corrects endothelial dysfunction Erythropoietin and a nonerythropoietic peptide analog promote aortic endothelial cell repair under hypoxic conditions: role of nitric oxide+1. Additive blood pressure lowering is possible, especially with ACE inhibitors or ARBs.
• Glucose-lowering agents: ARA-290 improves insulin sensitivity and glucose tolerance in animal models The Role of Erythropoietin in Metabolic Regulation+1. Additive glucose lowering may occur with insulin or GLP-1 receptor agonists.
• Chemotherapy: In preclinical models, ARA-290 reduced cisplatin nephrotoxicity and doxorubicin-induced oxidative stress An engineered non-erythropoietic erythropoietin-derived peptide, ARA290, attenuates doxorubicin induced genotoxicity and oxidative stress+1. Human data are absent.
• JAK inhibitors: Because ARA-290 signals through EPOR-CD131/JAK2-STAT3, JAK inhibition could blunt efficacy Pegmolesatide ameliorates indoxyl sulfate-induced cardiomyocyte hypertrophy through modulating the EPOR-CD131-dependent JAK2/STAT3 signaling pathway. Avoid combining outside clinical trials.
• TRPV1 modulators: ARA-290 relieves neuropathic pain partly via TRPV1 ARA 290 relieves pathophysiological pain by targeting TRPV1 channel: Integration between immune system and nociception. Additive analgesia possible.

No randomized trial has tested ARA-290 cycling schedules. Published phase 2 studies used time-limited courses, not continuous daily use A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema+1. Community protocols typically use 4 mg subcutaneously once daily for 28-42 days, followed by 2-4 weeks off before considering another course (community protocol). For acute injury support, shorter courses of 10-14 days are sometimes used (community protocol).

The rationale for cycling comes from the receptor's biology. The innate repair receptor is upregulated by injury or inflammation, and ARA-290 plasma half-life is about 2 minutes but downstream tissue-protective signaling persists, suggesting episodic targeting may be sufficient Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin. Tolerance or receptor desensitization has not been formally demonstrated for ARA-290, but intermittent dosing is consistent with the finite courses in available clinical data A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema+1.

No formal peptide combination studies exist. Community protocols sometimes combine ARA-290 with other repair or anti-inflammatory peptides.

• BPC-157: Both support tissue repair and reduce inflammation; no antagonism expected. Common community stack for healing (community protocol).
• TB-500 (thymosin beta-4): Both promote wound repair and angiogenesis. Additive benefit possible, but combined angiogenic activity warrants caution in cancer (community protocol).
• GHK-Cu: Tissue remodeling and anti-inflammatory actions overlap with ARA-290, but no direct data.
• GLP-1 receptor agonists (semaglutide, tirzepatide): ARA-290 improves insulin sensitivity in metabolic models Immunometabolic dysregulation drives selective executive cognitive dysfunction in male db/db mice. Additive glucose lowering is possible; monitor glucose (community protocol).
• EPO or ESAs: Avoid combining with EPO or other ESAs outside trials (community protocol).

ARA-290 is not FDA-approved for any indication A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema+1. It is not scheduled under the US Controlled Substances Act. The corpus documents only investigational use, including a phase 2 RCT in diabetic macular edema A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema and clinical assessments in sarcoidosis-associated small fiber neuropathy Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain. No EMA marketing authorization or MHRA/TGA approval is documented.

For sports, EPO is prohibited by WADA under category S2 at all times. ARA-290 itself is a non-hematopoietic EPO-derived peptide and does not appear to have a WADA-specific classification in the corpus. Testing sensitivity for this short-lived peptide is limited. Products marketed as research chemicals are not approved for human use.

In phase 2 studies, ARA-290 did not produce a consistent serious safety signal A Phase 2 Clinical Trial on the Use of Cibinetide for the Treatment of Diabetic Macular Edema+1. Because it selectively activates the innate repair receptor rather than the EPO homodimer, it does not stimulate red blood cell production, so hypertension, polycythemia, and thrombotic events are not expected Flipping the molecular switch for innate protection and repair of tissues: Long-lasting effects of a non-erythropoietic small peptide engineered from erythropoietin.

The most common reported events are mild injection-site reactions, such as redness, itching, or local discomfort (practitioner consensus). Transient headache, fatigue, and mild nausea are reported at low frequency early in treatment (community protocol). Long-term safety beyond 28-day cycles, immunogenicity, and drug interaction profiles remain uncharacterized. Relative contraindications include active malignancy, pregnancy, breastfeeding, and pediatric use due to absent human data. No specific lab monitoring is required, but baseline and periodic CBC and inflammatory markers have been used in practice (community protocol).