Cibinetide

Cibinetide, also known as ARA-290, is an eleven-residue peptide developed from the exposed surface of erythropoietin. Its design sought tissue-protective activity without the red-cell production stimulated by the full protein. Small human trials have investigated neuropathic symptoms and nerve imaging, especially in sarcoidosis. Some findings favor the peptide, while general pain measures, skin-nerve density and several treatment comparisons remain negative or inconclusive. The resulting evidence is strongest as an early investigation of specific nerve endpoints.

Overview

Erythropoietin, or EPO, is best known for supporting red-cell production. Its tissue-protective effects in experimental systems led investigators to study which portions of its structure might preserve those actions. Cibinetide emerged from that work as a short peptide intended to mimic an exposed three-dimensional surface. The design is therefore explained through the folded protein's surface, even though the new chain has its own sequence. Brines et al., 2008.

FDA's substance record identifies cibinetide with a pyroglutamyl N terminus and maps the ARA-290 and pHBSP names to it. That identity helps distinguish the peptide from full-length EPO and from the uncyclized HBSP preparation used in parts of the original discovery work. The molecular profile describes the identified peptide without assigning a salt formulation to every clinical study. FDA identity record.

Molecular profile

Aliases: ARA-290; ARA 290; pyroglutamyl helix-B surface peptide (pHBSP) Source
Length: 11 amino-acid residues Source
Identified peptide sequence: pGlu-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser-OH Source
Peptide formula, without an added salt: C51H84N16O21 Source
UNII: 9W5677JKDA Source
CAS: 1208243-50-8 Source

Forms and derivatives

HBSP and pyroglutamyl pHBSP

The discovery paper studied HBSP with an N-terminal glutamine and pHBSP with a cyclized pyroglutamate. Some HBSP batches contained both. FDA maps the pyroglutamyl sequence to cibinetide/ARA-290, so preparation identity remains attached to each finding.

Uses and research areas

Small sensory nerve fibers help detect pain and temperature, while small autonomic fibers contribute to functions such as sweating and blood-vessel regulation. Loss or dysfunction of these fibers can produce burning pain, abnormal sensitivity and autonomic symptoms. The sarcoidosis studies enrolled people with chronic painful small-fiber symptoms in an inflammatory disease setting. Heij et al., 2012.

The clinical program combined patient questionnaires with corneal confocal microscopy, an imaging method that visualizes small fibers in the clear front surface of the eye. Investigators also sampled skin nerves and measured walking. These outcomes provide complementary views of symptoms, local tissue structure and function. A separate diabetes trial examined another population with neuropathic symptoms and metabolic disease. Dahan et al., 2013, diabetes trial.

Mechanism of action

The original experimental rationale separates two EPO-associated receptor settings. Red-cell production involves paired EPO-receptor subunits. Tissue-protective research describes a complex involving the EPO receptor and CD131, often called the innate repair receptor. Cibinetide was developed to engage this protective response without the erythropoietic effect. The discovery work demonstrated injury-related effects and absent red-cell stimulation in the tested cell and animal systems. Brines et al., 2008.

This rationale creates a clinical question about injured nerves. If an inflammatory environment contributes to continuing fiber damage, a protective response might influence both symptoms and tissue structure. The trials therefore examined whether a change in reported discomfort accompanied an objective nerve measurement. A decrease in pain alone can arise through several mechanisms, and an imaging change alone does not establish how much sensory function returns.

The receptor model is useful for explaining why investigators chose this molecule. It does not supply a clinical estimate of repair in every organ. The studies below identify the particular tissues and populations in which outcomes were measured.

Pharmacokinetics

The original discovery paper reports an approximately two-minute plasma half-life for pHBSP after intravenous administration in rats and rabbits. Its detailed pharmacokinetic observations are in supplementary material. Clinical papers cite short human exposure after subcutaneous administration, but the acquired reports do not provide a complete original human analysis with analyte methods, population-specific estimates and uncertainty. Original preclinical report.

A pharmacokinetic figure is omitted because the source-specific numerical observations and statistical details needed for a faithful curve were not acquired. The research rationale allows tissue responses to continue after a short circulating exposure. Plasma measurements and downstream tissue responses therefore require separate observations.

Research findings

The pilot sarcoidosis trial showed a questionnaire-specific signal

The 2012 randomized, double-blind study included 22 participants, with 12 assigned ARA-290 and ten placebo. Over four weeks, the small-fiber neuropathy screening-list score improved more in the active group. Brief Pain Inventory and fatigue scores improved similarly in both groups. Heij et al., 2012.

The pilot supported further investigation of a particular symptom measure. Its several questionnaires did not move together, which is useful context when the study is described as showing “pain relief.” It also had a short observation window and a small number of participants.

Corneal and skin measurements differed in the next trial

The 2013 study enrolled 38 people with sarcoidosis-associated painful small-fiber loss, assigning 21 to ARA-290 and 17 to placebo for 28 days with a twelve-week follow-up. The area covered by nerve fibers in the cornea increased within the active group. Skin biopsies showed a small increase in nerve-fiber density in the lower leg and a small decrease in the thigh; both changes were too uncertain to establish an effect. Symptom measures also favored active treatment. The corneal analysis treated each eye as an independent sample, a choice that matters when considering statistical precision. Dahan et al., 2013.

A 2016 erratum corrected the arithmetic and normalization of the corneal area algorithm. The original absolute values therefore require correction before reuse. The finding retained here is the reported direction of the corneal response alongside the negative skin measurements; no uncorrected area graph is reproduced. Erratum.

Phase 2b favored one imaging comparison

The 2017 study randomized 64 people with sarcoidosis-associated nerve loss and neuropathic pain to one of three cibinetide doses or placebo for 28 days. Investigators imaged nerves in the cornea and measured the area occupied by their fibers. In the middle-dose group, the increase beyond placebo was 697 μm² (95% CI 159–1,236; P = 0.012). The corresponding intervals for the lower and higher doses included no difference, so those comparisons did not establish an increase beyond placebo. The middle-dose group also showed an increase in a skin marker associated with regenerating nerve fibers. Culver et al., 2017.

Pain improved in every group. The moderate-to-severe-pain subgroup comparison had P=0.157, so it did not establish superiority on that pain outcome. Correlations between nerve imaging and walking were biologically interesting, but correlation does not demonstrate a durable functional treatment benefit. This trial's primary question concerned corneal nerve area, which remains the clearest positive comparison.

The diabetes trial also produced mixed endpoints

A placebo-controlled phase 2 study enrolled 49 people with type 2 diabetes and neuropathic symptoms; 48 remained in the main analysis after one participant stopped because of worsening renal function. PainDetect scores favored ARA-290, while another small-fiber symptom list and sensory testing did not improve significantly. Across all participants, corneal nerve density increased slightly more with ARA-290 than with placebo, but the result was too uncertain to establish a treatment effect. A post hoc subgroup with low baseline density showed a within-group increase. Brines et al., 2014.

Selecting a subgroup with low baseline density concentrates the imaging question on people with an initial fiber deficit. Because that selection was post hoc and the reported increase was within the active group, it supplies a hypothesis for a prospectively defined comparison. The full-cohort result remains part of the same trial.

Safety and tolerability

The small 2012 pilot raised no clinical or laboratory safety concern. The 2013 sarcoidosis study reported no serious adverse event during treatment or its follow-up, and investigators did not judge the reported mild events likely to be drug-related. These findings describe tolerability of trial material within the cohorts studied. Pilot, 2013 trial.

The diabetes trial recorded four serious adverse events among participants receiving ARA-290; two were considered possibly related to treatment. One participant’s kidney function worsened while a diuretic was being increased, prompting study treatment to stop. Another developed severe cellulitis, an infection of skin and underlying tissue, followed by a fatal heart attack; the safety committee judged that event unrelated. These illnesses and other medicines make the cause of each event difficult to determine. Diabetes safety results.

FDA's current orphan-drug record lists the sarcoidosis-neuropathic-pain designation without approval for that indication. Its May 14, 2026 compounding-nomination document lists cibinetide in Category 3, substances nominated without adequate support. A substance identifier, orphan designation and nomination each have a specific administrative purpose; none supplies a finished-product approval. FDA orphan record, FDA nomination list.

What the research means

Cibinetide's clinical studies give a reason to investigate nerve repair in defined disease populations. They combine objective imaging with reported symptoms and provide several positive comparisons. Their value also depends on retaining the discordant results: corneal area can change while skin density or general pain measures remain unchanged, and one treatment arm can succeed while adjacent arms do not.

A disease-modifying claim needs more than a short imaging response. Longer controlled follow-up must show what happens to symptoms, sensory function and disability, and determine how reliably an imaging endpoint predicts those outcomes. Larger exposure sets are also needed to characterize uncommon harms. The existing results support that research direction while leaving the magnitude and durability of clinical benefit unresolved.

FAQs

Is ARA-290 the same name as cibinetide?

FDA's identity record maps ARA-290 to cibinetide and specifies the pyroglutamyl peptide. The original discovery paper also tested a related uncyclized HBSP preparation, which has its own material label. Clinical effects belong to the trial preparation.

Did every pain measure improve beyond placebo?

The pilot's small-fiber symptom list favored treatment, while its general pain and fatigue measures improved similarly in both groups. The later phase 2b pain-subgroup comparison was statistically inconclusive. Questionnaires and nerve imaging therefore need to be read as individual endpoints.

Why do these studies image nerves in the cornea?

Corneal confocal microscopy can visualize small fibers noninvasively. It offers an objective tissue measure that can be compared with symptoms and other nerve assessments. Its usefulness as a research marker still requires evidence connecting a treatment-induced change with durable patient benefit.

Did corneal improvement establish skin-nerve regeneration?

In the 2013 trial, corneal nerve-fiber area increased within the cibinetide group, but the study did not establish an increase in nerve density in sampled leg and thigh skin. A later trial found a change in a skin protein associated with growing nerve fibers. That protein measurement answers a different question from counting how many fibers are present.

Why retain the 2016 erratum?

It corrects arithmetic and normalization of corneal nerve-fiber area in the 2013 report. Absolute area values need the correction before reuse. The page links the notice and avoids reproducing an uncorrected graph.

Does the EPO-derived design stimulate red-cell production?

The experimental design aimed to retain protective activity while avoiding erythropoiesis. The discovery studies found no red-cell stimulation in their tested systems. That property is one part of the biological rationale; complete clinical safety still depends on observed patient outcomes.

Does an FDA orphan designation mean approval?

Designation supports development for a rare disease. The directly checked FDA sarcoidosis-pain record lists the compound as designated and unapproved for that indication. The substance identifier and compounding-nomination entry have separate administrative purposes.

Cibinetide's erythropoietin-derived design gives it a different biological starting point from mitochondrial-targeting elamipretide or the cell-survival peptide Humanin. Comparing them can clarify which molecular process and clinical endpoint each research program actually examines.

References

The sources preserve the original discovery paper and all three baseline sarcoidosis trials. The corneal-algorithm erratum, diabetes trial and current official identity/regulatory records supply additional context where it changes interpretation.

Brines M, Patel NSA, Villa P, Brines C, Mennini T, De Paola M, Erbayraktar Z, Erbayraktar S, Sepodes B, Thiemermann C, Ghezzi P, Yamin M, Hand CC, Xie QW, Coleman T, Cerami A. Nonerythropoietic, tissue-protective peptides derived from the tertiary structure of erythropoietin. Proceedings of the National Academy of Sciences USA. 2008;105(31):10925–10930. DOI: 10.1073/pnas.0805594105.
The discovery work explains the surface-mimic rationale and distinguishes HBSP from its pyroglutamyl form across preclinical systems.
Heij L, Niesters M, Swartjes M, Hoitsma E, Drent M, Dunne A, Grutters JC, Vogels O, Brines M, Cerami A, Dahan A. Safety and efficacy of ARA 290 in sarcoidosis patients with symptoms of small fiber neuropathy: a randomized, double-blind pilot study. Molecular Medicine. 2012;18:1430–1436. DOI: 10.2119/molmed.2012.00332.
A small randomized study found a symptom-list signal, while general pain and fatigue measures did not separate from placebo.
Dahan A, Dunne A, Swartjes M, Proto PL, Heij L, Vogels O, van Velzen M, Sarton E, Niesters M, Tannemaat MR, Cerami A, Brines M. ARA 290 improves symptoms in patients with sarcoidosis-associated small nerve fiber loss and increases corneal nerve fiber density. Molecular Medicine. 2013;19:334–345. DOI: 10.2119/molmed.2013.00122. Corneal algorithm corrected in 2016.
In the trial of 38 people with sarcoidosis-associated nerve-fiber loss, corneal nerve-fiber area increased within the ARA-290 group. Skin biopsies showed a small increase in lower-leg nerve-fiber density and a decrease in thigh density, with both changes too uncertain to establish an effect. The corneal calculation later required correction.
Culver DA, Dahan A, Bajorunas D, Jeziorska M, van Velzen M, Aarts LPHJ, Tavee J, Tannemaat MR, Dunne AN, Kirk RI, Petropoulos IN, Cerami A, Malik RA, Brines M. Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Pain. Investigative Ophthalmology & Visual Science. 2017;58(6):BIO52–BIO60. DOI: 10.1167/iovs.16-21291.
The phase 2b primary imaging comparison favored the middle active group. Adjacent arms and a pain-subgroup comparison remained inconclusive.
Dahan A, Dunne A, Swartjes M, Proto PL, Heij L, Vogels O, van Velzen M, Sarton E, Niesters M, Tannemaat MR, Cerami A, Brines M. Erratum to: ARA 290 Improves Symptoms in Patients with Sarcoidosis-Associated Small Nerve Fiber Loss and Increases Corneal Nerve Fiber Density. Molecular Medicine. 2016;22:674. DOI: 10.2119/molmed.2013.00122.erratum.
The notice corrects the 2013 corneal area algorithm and normalization. It is a correction to the same cohort, not another trial.
Brines M, Dunne AN, van Velzen M, Proto PL, Ostenson CG, Kirk RI, Petropoulos IN, Javed S, Malik RA, Cerami A, Dahan A. ARA 290, a Nonerythropoietic Peptide Engineered from Erythropoietin, Improves Metabolic Control and Neuropathic Symptoms in Patients with Type 2 Diabetes. Molecular Medicine. 2014;20:658–666. DOI: 10.2119/molmed.2014.00215.
The detailed report gives mixed neuropathy and imaging outcomes plus serious-event observations that need to accompany the favorable abstract.
U.S. Food and Drug Administration. Substance Registration System: Cibinetide, UNII 9W5677JKDA. Accessed October 13, 2026.
The official identity record gives the pyroglutamyl sequence, elemental formula and ARA 290 aliases, with an explicit statement that identity registration does not imply approval.
U.S. Food and Drug Administration. Orphan Drug Designations and Approvals: cibinetide peptide for neuropathic pain in patients with sarcoidosis, record 349111. Accessed October 13, 2026.
The current record lists a designation dated September 13, 2011 and no FDA approval for the orphan indication.
U.S. Food and Drug Administration. Bulk Drug Substances Nominated for Use in Compounding Under Section 503A of the Federal Food, Drug, and Cosmetic Act. Updated May 14, 2026.
The current document lists cibinetide among Category 3 substances nominated without adequate support.

Glossary

Erythropoietin (EPO): A protein hormone that supports red-cell production and has tissue-protective actions in experimental systems.
Erythropoiesis: The production of red blood cells.
Pyroglutamate: A cyclized amino-acid residue at the peptide's N terminus.
Innate repair receptor: The EPO-receptor/CD131 complex described in the tissue-protection research underlying cibinetide.
Small-fiber neuropathy: Damage or dysfunction affecting small sensory or autonomic nerve fibers.
Sarcoidosis: An inflammatory disease involving collections of immune cells in affected tissues.
Corneal confocal microscopy: Imaging that visualizes small nerve fibers in the cornea.
CNFA: Corneal nerve-fiber area, an image-derived measurement of the area occupied by fibers.
Epidermal nerve density: A measure of the nerve fibers entering the skin's outer layer.
GAP-43: A protein associated with growing nerve fibers, measured here as a regeneration-related marker.
Surrogate endpoint: A measurement used to investigate or predict clinical benefit; its relationship to patient outcomes needs validation.
Post hoc subgroup: A group examined in an additional analysis after the main study plan or results.