ARA-290 (cibinetide) is an 11-amino-acid synthetic peptide derived from the tissue-protective helix B surface region of erythropoietin (EPO) — engineered to activate the innate repair receptor (IRR) for tissue protection, anti-inflammatory signaling, and nerve repair without stimulating red blood cell production or carrying any of the cardiovascular risks associated with EPO therapy.

ARA-290 (cibinetide) is an 11-amino-acid synthetic peptide derived from the tissue-protective helix B surface region of erythropoietin (EPO) — engineered to activate the innate repair receptor (IRR) for tissue protection, anti-inflammatory signaling, and nerve repair without stimulating red blood cell production or carrying any of the cardiovascular risks associated with EPO therapy. Among research peptides, ARA-290 occupies a distinctive position: it has more human clinical trial data than most compounds in the peptide space, including Phase 2 randomized controlled trials for sarcoidosis-associated small fiber neuropathy and diabetic neuropathy, and it holds both FDA Orphan Drug and Fast Track designations for neuropathic pain in sarcoidosis.

The scientific concept behind ARA-290 is elegant. EPO performs two biologically distinct functions: it drives red blood cell production through the classical homodimeric EPO receptor (EPOR), and it protects and repairs injured tissue through a separate heterodimeric receptor called the innate repair receptor (IRR). ARA-290 was specifically designed to activate only the second function — tissue protection and repair — while leaving erythropoiesis completely untouched. PSPeptides offers research-grade ARA-290 for laboratory applications studying innate repair receptor biology, neuroprotection, and inflammatory modulation.

What Is the Innate Repair Receptor and How Does ARA-290 Activate It?

The innate repair receptor (IRR) is a heterodimeric receptor complex composed of two subunits: the erythropoietin receptor (EPOR) and the beta-common receptor (CD131, also called βcR). This receptor was characterized by Michael Brines and Anthony Cerami in a landmark 2004 paper published in the Proceedings of the National Academy of Sciences (PNAS) that fundamentally reshaped the understanding of EPO biology.

The critical insight was that EPO’s tissue-protective effects — documented in brain, heart, kidney, and peripheral nerve tissue — were not mediated through the same receptor that drives red blood cell production. The classical erythropoietic EPO receptor is a homodimer (two EPOR subunits), while the tissue-protective receptor is a heterodimer (EPOR + CD131). This distinction explained a longstanding puzzle: why did EPO protect neurons and cardiac cells that express too few EPOR homodimers for classical EPO signaling?

The answer was the IRR. This heterodimeric receptor is selectively upregulated in injured and inflamed tissue and is largely absent from healthy, uninjured cells — meaning it provides a damage-sensing signal that activates repair pathways only where repair is needed. When ARA-290 binds to the IRR, it initiates several downstream effects: anti-apoptotic signaling (preventing programmed cell death in injured but salvageable cells), suppression of pro-inflammatory cytokine cascades (reducing TNF-α, IL-1β, and IL-6 production), and inhibition of microglial activation (reducing neuroinflammation in nervous tissue). These effects occur without any activation of erythropoiesis — ARA-290 does not bind the classical EPOR homodimer with sufficient affinity to stimulate red blood cell production.

What Does the Clinical Trial Data Show About ARA-290?

ARA-290 has more published human clinical data than the vast majority of research peptides — a fact that distinguishes it from compounds that rely entirely on preclinical animal and cell culture evidence.

Sarcoidosis small fiber neuropathy (Phase 2): The most advanced clinical data comes from Phase 2 trials conducted at the Leiden University Medical Center in the Netherlands. Sarcoidosis-associated small fiber neuropathy (SFN) is a painful condition caused by damage to the small unmyelinated nerve fibers responsible for pain and temperature sensation. Published results from a 2017 dose-ranging trial demonstrated that ARA-290 at 4 mg subcutaneously daily for 28 days met its primary endpoint: a significant placebo-corrected increase in corneal nerve fiber area — an objective biomarker of small nerve fiber regeneration measured by confocal microscopy. This finding was significant because it provided structural evidence of nerve repair, not just symptomatic improvement — the damaged nerve fibers were actually regrowing.

Diabetic neuropathy and metabolic effects (Phase 2): A 2015 Phase 2 trial published in Molecular Medicine (Brines et al.) evaluated ARA-290 in type 2 diabetes patients. The study found that ARA-290 improved HbA1c (a marker of long-term blood sugar control) and lipid profiles. Additionally, treated patients showed improvements in neuropathic symptom scores. The metabolic effects were unexpected — suggesting the innate repair receptor may play a role in metabolic regulation beyond its known tissue-protective functions. These metabolic findings have attracted interest from researchers studying the intersection of inflammation and metabolic dysfunction.

Corneal nerve fiber density: Across the clinical trials, corneal confocal microscopy provided the most robust objective endpoint. The cornea is the most densely innervated tissue in the human body, and corneal nerve fiber density serves as a surrogate biomarker for systemic small fiber neuropathy — allowing non-invasive, quantitative measurement of nerve fiber regeneration. ARA-290’s ability to increase corneal nerve fiber area represents structural evidence of nerve regeneration that goes beyond subjective pain scores or functional assessments.

Safety profile: Across all published clinical trials, ARA-290 was well-tolerated with no serious adverse events attributed to the drug. Critically, no effects on hematocrit or red blood cell counts were observed at any dose — confirming that the peptide’s tissue-protective activity is fully dissociated from erythropoietic activity. The clinical trial dosing (4 mg SC daily for 28 days) did not produce the cardiovascular risks (hypertension, thrombosis) associated with EPO therapy. This safety profile earned ARA-290 both FDA Orphan Drug and Fast Track designations for sarcoidosis-related neuropathic pain.

How Does ARA-290 Compare to Other Tissue-Protective and Anti-Inflammatory Peptides?

The research peptide landscape includes several compounds with tissue-protective and anti-inflammatory properties, but ARA-290’s mechanism — innate repair receptor activation — is unique. Understanding how it compares to other peptides helps researchers select the right tool for their specific investigation.

ARA-290’s key differentiator is its selectivity for injured tissue. The IRR is upregulated specifically at sites of injury and inflammation — meaning ARA-290’s effects are concentrated where damage has occurred rather than acting globally. This injury-selective activation contrasts with BPC-157’s broader angiogenic and cytoprotective effects, TB-500’s generalized actin-mediated wound healing, and KPV’s systemic NF-κB inhibition. For researchers studying tissue repair from a vascular perspective, our BPC-157 guide covers VEGF-mediated angiogenesis. For actin-based repair mechanisms, our TB-500 guide covers cytoskeletal regulation. For NF-κB-targeted inflammation, our KPV guide covers that pathway.

ARA-290 and Neuropathic Pain Research

The neuropathic pain application is where ARA-290’s clinical evidence is strongest. Neuropathic pain — pain caused by damage to the nervous system itself rather than by tissue injury — is one of the most challenging conditions in medicine. It affects an estimated 7-10% of the population and responds poorly to conventional analgesics. Current treatments (anticonvulsants, antidepressants, opioids) manage symptoms without addressing the underlying nerve damage.

ARA-290’s approach is fundamentally different. Rather than masking pain signals, it promotes the structural repair of damaged nerve fibers — as demonstrated by the corneal nerve fiber area increases documented in clinical trials. The proposed mechanism involves IRR activation on Schwann cells (the cells that maintain and repair peripheral nerve myelin), damaged neurons, and local immune cells. By reducing neuroinflammation (microglial activation), preventing further neuronal apoptosis, and potentially supporting Schwann cell-mediated nerve regeneration, ARA-290 addresses the pathology rather than the symptom.

Published research has also linked ARA-290’s analgesic effects to modulation of the TRPV1 channel — a receptor at the intersection of the immune and nociceptive systems. TRPV1 activation mediates inflammatory pain signaling, and ARA-290’s ability to modulate this channel may contribute to its pain-relieving effects alongside its structural nerve repair activity. A 2016 review in Pain Reports by Dahan, Brines, Niesters, Cerami, and van Velzen titled “Targeting the innate repair receptor to treat neuropathy” summarized the case for the IRR as a clinically actionable pain target — connecting the mechanistic research to the clinical trial outcomes.

ARA-290 Research Beyond Neuropathy: Preclinical Applications

While the clinical trial program focused on neuropathic pain, preclinical research on ARA-290 and the innate repair receptor has explored several additional applications where injury-selective tissue protection is relevant.

Diabetic retinopathy: The retina, like the cornea, is densely innervated and highly metabolically active — making it vulnerable to the microvascular and neural damage caused by diabetes. Preclinical studies have evaluated ARA-290 for protection of retinal neurons and microvasculature in diabetic models, with published data showing reduced retinal cell apoptosis and preserved retinal function following IRR activation. This application extends the nerve-repair mechanism from peripheral small fibers (sarcoidosis SFN) to central retinal neurons — broadening the potential scope of IRR-targeted therapy.

Traumatic brain injury: Published preclinical data has evaluated EPO-derived peptides including ARA-290 for neuroprotection following traumatic brain injury. The IRR is upregulated in injured brain tissue following trauma, and its activation by ARA-290 reduced neuronal apoptosis, microglial-mediated neuroinflammation, and functional deficits in animal models. For researchers studying neuroprotective peptides through different mechanisms, Semax provides BDNF-mediated neuroprotection, and Selank provides GABAergic neuroprotection — complementary approaches that target different aspects of neural injury and recovery.

Cardiac ischemia-reperfusion: The heart is one of the tissues where EPO’s tissue-protective effects were first documented, and the IRR is expressed in cardiac tissue. Preclinical studies have shown that ARA-290 reduces infarct size and preserves cardiac function in ischemia-reperfusion models — protecting cardiomyocytes from the secondary damage that occurs when blood flow is restored after ischemia. For researchers studying cardiac mitochondrial protection through a different mechanism, our SS-31 guide covers cardiolipin stabilization in cardiac mitochondria.

Chronic kidney disease: The kidney is another tissue with documented IRR expression, and preclinical studies have evaluated ARA-290 for renal protection in models of acute kidney injury and chronic kidney disease. The anti-apoptotic and anti-inflammatory effects of IRR activation may reduce tubular cell death and interstitial inflammation — the pathological processes that drive progressive kidney damage.

ARA-290 Research Protocols and Handling

The clinical trial protocol for ARA-290 is well-established: 4 mg administered subcutaneously once daily for 28 days. This dose was identified through Phase 2 dose-ranging studies as the most effective for increasing corneal nerve fiber density in sarcoidosis SFN patients. PSPeptides supplies ARA-290 as a lyophilized powder for reconstitution.

For reconstitution, use bacteriostatic water following standard aseptic technique as described in our reconstitution guide. Direct the water stream against the vial wall, allow gentle dissolution, and never shake. For dosing calculations, our peptide calculator guide covers mass-to-volume conversions. Reconstituted ARA-290 should be refrigerated at 2-8°C and used within 28 days. Unreconstituted vials should be stored at -20°C for long-term preservation. For comprehensive storage protocols, see our peptide storage guide.

The 28-day treatment course used in clinical trials reflects the time required for measurable nerve fiber regeneration to occur — a structural repair process that is inherently slower than symptomatic relief. Researchers should design protocols with sufficient duration to observe the structural endpoints (nerve fiber density, corneal confocal microscopy) that distinguish ARA-290’s regenerative mechanism from symptom management. For guidance on peptide treatment duration, our cycling guide covers the principles of course-based versus continuous peptide administration.

ARA-290 in the 2026 Regulatory Landscape

ARA-290’s regulatory history is informative for researchers. The peptide received FDA Orphan Drug designation and Fast Track designation for neuropathic pain in sarcoidosis, plus EU orphan designation — development incentives reflecting the regulatory agencies’ recognition of the unmet medical need and the scientific promise of the innate repair receptor mechanism. However, no New Drug Application (NDA) was ever submitted, and the original developer (Araim Pharmaceuticals) reportedly wound down its development program. Published sources attribute the stall to commercial and organizational factors rather than safety or efficacy concerns.

This creates an unusual situation: ARA-290 has Phase 2 clinical data of reasonable quality, regulatory designations that recognized its therapeutic promise, and a well-characterized mechanism with a solid scientific foundation — but no ongoing clinical development program or path to approval. For researchers, this means ARA-290 is available only as a research-grade compound for laboratory use, not as an approved pharmaceutical. For broader regulatory context, our FDA reclassification guide covers the 2026 changes affecting the peptide landscape, and our legal status guide covers the regulatory framework for research peptides.

Why ARA-290 Research Is Relevant in 2026

Despite the stalled development program, ARA-290 research remains relevant for several reasons. The innate repair receptor concept — a damage-selective tissue repair pathway that can be pharmacologically activated without erythropoietic side effects — is scientifically compelling and has been validated by the clinical data showing measurable nerve regeneration. The unmet need in neuropathic pain remains enormous, and conventional treatments continue to provide only symptomatic relief without structural repair. And the metabolic effects observed in the diabetes trials have opened a new research direction connecting IRR activation to metabolic health — an area that intersects with the broader metabolic peptide landscape including compounds like retatrutide and MOTS-C that approach metabolic regulation through entirely different receptor systems.

For researchers studying tissue protection and repair, ARA-290 offers a mechanism that no other available peptide provides — selective activation of the IRR at sites of injury. This complements rather than duplicates the mechanisms of BPC-157 (angiogenesis), TB-500 (actin-mediated cell migration), and KPV (NF-κB inhibition) — each addressing tissue repair through distinct molecular pathways. For multi-peptide tissue repair protocols, our stacking guide covers the principles of combining peptides from different mechanism classes.

Further Reading

For additional peer-reviewed research, see: Innate repair receptor discovery (Brines & Cerami, PNAS).

Understanding ara-290 is essential for researchers navigating this rapidly evolving field in 2026.

Frequently Asked Questions

What is ARA-290 and how does it work?

ARA-290 (cibinetide) is an 11-amino-acid peptide derived from the tissue-protective region of erythropoietin. It activates the innate repair receptor (IRR) — a heterodimeric receptor (EPOR/CD131) selectively upregulated in injured tissue — to produce anti-apoptotic, anti-inflammatory, and nerve-regenerative effects without stimulating red blood cell production or carrying EPO’s cardiovascular risks.

Does ARA-290 have human clinical trial data?

Yes — more than most research peptides. Phase 2 trials demonstrated increased corneal nerve fiber area (structural nerve regeneration) in sarcoidosis SFN patients, and improved HbA1c and neuropathic symptoms in type 2 diabetes patients. ARA-290 holds FDA Orphan Drug and Fast Track designations for sarcoidosis neuropathic pain.

How does ARA-290 differ from BPC-157 for tissue repair?

ARA-290 activates the innate repair receptor, which is selectively upregulated in damaged tissue — providing injury-targeted anti-apoptotic and anti-inflammatory effects. BPC-157 promotes repair through VEGF-mediated angiogenesis and nitric oxide modulation — providing vascular supply and cytoprotection. Their mechanisms are complementary: ARA-290 targets the damage-sensing repair pathway, BPC-157 targets the vascular infrastructure supporting repair.

Is ARA-290 FDA approved?

No. ARA-290 received FDA Orphan Drug and Fast Track designations (development incentives, not approvals), but no NDA was submitted and development stalled after Phase 2. It is available only as a research-grade compound from suppliers like PSPeptides for laboratory use.

All PSPeptides products are sold exclusively for research and laboratory use.