ARA-290
Also known as: ARA 290, Cibinetide, pHBSP, pyroglutamate helix B surface peptide, helix B surface peptide derivative
3 notable studies · 4 references
TLDR
Cibinetide (ARA-290) is an 11-amino-acid erythropoietin-derived peptide designed to activate tissue-protective signaling without stimulating red-blood-cell production, with randomized human studies showing encouraging effects on symptoms and objective nerve-fiber measures in small-fiber neuropathy, although its precise receptor mechanism and long-term clinical efficacy remain unresolved.
Research Supports
- Studied for effects on small-fiber neuropathy, including sarcoidosis- and diabetes-associated neuropathy
- Investigated for effects on nerve regeneration using corneal nerve-fiber measures
- Examined for effects on neuropathic pain
- Studied for anti-inflammatory and tissue-protective signaling
Observations Reported in Research
- Produced significantly greater improvement in Small Fiber Neuropathy Screening List score than placebo in a 22-person sarcoidosis trial (Heij et al., 2012)
- Increased corneal nerve-fiber area in a 64-person Phase 2b sarcoidosis trial, an objective marker consistent with nerve regeneration (Culver et al., 2017)
- Improved neuropathic symptom scores and increased corneal nerve-fiber density in people with type 2 diabetes and painful neuropathy (Brines et al., 2014/2015)
- A 2018 investigation found no direct biophysical evidence for the proposed EPOR/CD131 "innate repair receptor" structure
These are brief summaries of what the referenced research examined or reported — not conclusions about safety or effectiveness, and not medical advice. See Notable Studies and Sources & References below for the full context and citations.
At a Glance
Classification: Synthetic 11-amino-acid erythropoietin-derived peptide; non-erythropoietic tissue-protective peptide; experimental innate-repair signaling agonist
Cibinetide, originally known as ARA-290, is an 11-amino-acid peptide engineered from the three-dimensional structure of helix B of erythropoietin (EPO). It was designed to separate two very different aspects of EPO biology: EPO → red blood-cell production from EPO-associated tissue-protective signaling. ARA-290 was designed to retain the second without meaningfully stimulating erythropoiesis. Research has focused heavily on small-fiber neuropathy, neuropathic pain, nerve regeneration, sarcoidosis, diabetic neuropathy, inflammation, tissue repair, and metabolic dysfunction. Importantly, Cibinetide has been administered directly to humans in randomized controlled trials, which makes its evidence base substantially different from many experimental peptides on Aminodex.
What Is ARA-290?
Erythropoietin is best known for stimulating red-blood-cell production. But researchers discovered that EPO also produces tissue-protective effects in experimental injury models. Using structural information from EPO, researchers developed a small peptide representing the exposed surface of its helix-B region. The resulting molecule was ARA-290, later called Cibinetide. It contains only 11 amino acids and lacks EPO's conventional erythropoietic activity. Its reported plasma half-life is only about two minutes, yet biological effects can persist much longer. Researchers have interpreted this as transient receptor activation triggering longer-lasting cellular repair programs rather than requiring continuous circulating exposure.
What Are Researchers Studying?
Small-fiber neuropathy
This is Cibinetide's best-developed human research area. Small-fiber neuropathy affects small sensory and autonomic nerve fibers and can produce burning pain, abnormal temperature sensation, autonomic symptoms, tingling, and altered sensation. Cibinetide has been studied particularly in small-fiber neuropathy associated with sarcoidosis and type 2 diabetes. Multiple randomized human trials have reported improvements in some neuropathy measures.
Nerve regeneration
One of the most interesting findings is that researchers didn't rely exclusively on pain questionnaires. Corneal confocal microscopy can quantify small nerve fibers in the cornea. In a 64-person Phase 2b trial of sarcoidosis-associated small-fiber loss, Cibinetide increased corneal nerve-fiber area, providing an objective biological signal consistent with nerve regeneration or restoration. That is much stronger mechanistically than simply reporting that people said their pain felt better. However, corneal nerve-fiber changes remain a surrogate marker and don't automatically establish durable clinical benefit.
Neuropathic pain
Animal models demonstrated sustained reductions in mechanical and cold allodynia following ARA-290 treatment. Human trials subsequently reported improvement in several neuropathy-related symptom measures. Pain results haven't been uniformly positive across every measurement. In the original 22-person sarcoidosis trial, the overall small-fiber-neuropathy symptom score improved significantly versus placebo, while some pain and fatigue measures improved similarly in both groups.
Diabetic neuropathy
Cibinetide has also been studied in people with type 2 diabetes and painful neuropathy. Participants received 4 mg subcutaneously each day for 28 days, followed by another month of observation. Researchers reported improvement in PainDetect neuropathy scores and, in participants with reduced baseline corneal nerve-fiber density, increased corneal nerve-fiber density compared with placebo. Metabolic measures including HbA1c and lipid profiles also changed during the study. These findings were exploratory and shouldn't be interpreted as establishing Cibinetide as a diabetes treatment.
Inflammation
Cibinetide was designed around EPO-associated tissue-protection pathways without activating conventional erythropoiesis. Experimental research suggests effects involving inflammatory-cell activation, cytokine signaling, tissue injury responses, microglial activity, and repair signaling. Animal experiments show anti-inflammatory effects across several injury models.
Tissue protection and repair
Preclinical research extends far beyond neuropathy. ARA-290 has been investigated in experimental kidney injury, burns, neurological injury, cardiac injury, and metabolic disease. For example, systemic ARA-290 preserved microvascular patency and reduced inflammatory signaling after experimental burns in mice. This supports broad tissue-protection biology. It does not mean every organ-protection finding translates to humans.
How Does It Work?
The commonly proposed model involves the innate repair receptor (IRR). Researchers have described this as a receptor complex involving erythropoietin receptor (EPOR) and β-common receptor / CD131. Activation is proposed to trigger cytoprotection, anti-inflammatory signaling, tissue repair, and nerve restoration. Cibinetide was designed to activate this repair-associated signaling without activating the conventional EPOR homodimer responsible for erythropoiesis. The precise structural model of the EPOR/CD131 “innate repair receptor” remains debated. A 2018 investigation found no direct biophysical evidence that the extracellular regions of EPOR and β-common receptor specifically associate as proposed, even though functional relationships between these pathways have been reported. Aminodex should say “proposed innate repair receptor mechanism” rather than presenting the receptor architecture as completely settled science.
What Does the Research Show?
Human research
Moderate and unusually substantive for an experimental research peptide. Cibinetide has been evaluated in randomized trials, placebo-controlled trials, repeated subcutaneous administration, sarcoidosis-associated small-fiber neuropathy, and diabetic neuropathy. A 22-person randomized double-blind pilot trial found a significantly larger improvement in the Small Fiber Neuropathy Screening List score with ARA-290 than placebo. A subsequent blinded placebo-controlled sarcoidosis study reported improvements in neuropathic symptoms alongside increases in corneal nerve-fiber density and changes in sensory thresholds and walking capacity. A later 64-person Phase 2b study again demonstrated objective changes in corneal nerve fibers. Human evidence therefore clearly exists. What has not been established is broad clinical efficacy across neuropathies or other diseases.
Animal research
Extensive. ARA-290 has been investigated in models involving peripheral nerve injury, neuropathic pain, burns, kidney injury, diabetes, and inflammation. Knockout experiments have also been used to investigate whether CD131/β-common-receptor signaling is necessary for its effects.
In-vitro research
Substantial mechanistic research exists around EPO-derived tissue-protective signaling, inflammatory pathways, cellular survival, receptor signaling, and neural repair. The principal uncertainty isn't whether Cibinetide has biological activity. It's exactly how its receptor biology works and whether the encouraging small clinical trials translate into meaningful larger-scale therapeutic benefit.
Notable Studies
Safety and Efficacy of ARA 290 in Sarcoidosis Patients With Symptoms of Small Fiber Neuropathy: A Randomized, Double-Blind Pilot Study
humanTwenty-two patients with sarcoidosis-associated small-fiber neuropathy received IV ARA-290 or placebo three times weekly for four weeks. The ARA-290 group experienced significantly greater improvement in the Small Fiber Neuropathy Screening List score than placebo. No major safety concerns emerged during the study.
Limitations: Very small exploratory study. Some individual pain/fatigue measures improved similarly in both groups, and the study was not large enough to establish definitive clinical efficacy.
View publication →ARA 290, a Nonerythropoietic Peptide Engineered From Erythropoietin, Improves Metabolic Control and Neuropathic Symptoms in Patients With Type 2 Diabetes
humanParticipants with type 2 diabetes and painful neuropathy received 4 mg ARA-290 or placebo subcutaneously each day for 28 days. Neuropathic symptom scores improved, and participants with reduced baseline corneal nerve-fiber density showed an increase in nerve-fiber density compared with placebo. Metabolic measures also changed during follow-up.
Limitations: Small exploratory trial, relatively short duration and multiple outcomes. Findings do not establish treatment of diabetes or broad diabetic-neuropathy efficacy.
View publication →Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain
humanSixty-four participants with sarcoidosis-associated small-nerve-fiber loss and neuropathic pain received Cibinetide or placebo for 28 days. Researchers used corneal confocal microscopy and other measures to investigate structural nerve changes, symptoms and function. Cibinetide increased corneal nerve-fiber area, supporting a potential regenerative biological effect.
Limitations: Short treatment period and surrogate nerve-regeneration endpoints. The study doesn't establish long-term prevention of neuropathy progression or durable clinical benefit.
View publication →What We Still Don't Know
Whether benefits persist long-term. Whether larger trials would reproduce the neuropathy findings. Which neuropathies respond. Whether structural nerve changes translate into durable functional improvement. Long-term human safety. Optimal treatment duration. Effects in healthy individuals. Whether metabolic findings are clinically meaningful. Whether it modifies diabetes itself. Whether the proposed EPOR/CD131 receptor architecture is correct. Whether broader organ-protection findings translate from animals to humans. Whether research-market ARA-290 corresponds to clinical-development Cibinetide material.
Related Compounds
Recent publications
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Sources & References
- Heij L, et al. Safety and efficacy of ARA 290 in sarcoidosis patients with symptoms of small fiber neuropathy. Molecular Medicine. 2012.
- ARA 290, a nonerythropoietic peptide engineered from erythropoietin, improves metabolic control and neuropathic symptoms in patients with type 2 diabetes.
- Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain.
- Brines M, et al. Flipping the molecular switch for innate protection and repair of tissues. 2015.
Supplier Listings
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