ARA-290 / Cibinetideerythropoietin's repair signal, engineered without the red-cell effect
ARA-290 — also called cibinetide — is an experimental peptide designed to copy the repair-signaling part of erythropoietin (EPO) without turning on red-blood-cell production. Its strongest human research signal is in small fiber neuropathy, especially the nerve pain and nerve-fiber loss seen in sarcoidosis. It is not FDA-approved and remains investigational — and "non-erythropoietic" does not automatically mean "proven safe."
Cibinetide is an 11-amino-acid, EPO-derived helix-B surface peptide investigated as a non-erythropoietic tissue-protective agent. Phase II/pilot studies suggest possible benefit in sarcoidosis-associated small fiber neuropathy, while diabetic-neuropathy/metabolic and diabetic-macular-edema findings remain exploratory or negative on primary endpoints. Most clinical work used 4 mg subcutaneous once daily.
ARA-290/pHBSP (CAS 1208243-50-8; C₅₁H₈₄N₁₆O₂₁; MW ~1257.3 Da; pGlu-Glu-Gln-Leu-Glu-Arg-Ala-Leu-Asn-Ser-Ser) is modeled on the tissue-protective helix-B surface of EPO. It is proposed to engage a non-hematopoietic innate repair receptor (IRR) involving EPOR and the β-common receptor (CD131), though the receptor architecture remains debated. Plasma t½ is ~minutes, but downstream signaling persists far longer.
11-aaEPO helix-B surface peptide
IRREPOR + β-common (CD131)
Phase IISarcoidosis SFN · human signal
4 mg SCDaily · study-anchor dose
Status
Not FDA-approved · investigational · 503A Category 3
A genuine Phase II signal — in one narrow indication.
ARA-290 has a stronger human evidence base than most "research peptides," but it's important to be precise about where. The real signal is sarcoidosis-associated small fiber neuropathy — multiple small Phase II/pilot studies showing reduced neuropathic pain and increased corneal/skin nerve-fiber abundance. Elsewhere the picture is thinner: the diabetic-macular-edema trial was negative on its primary endpoints, and the type-2-diabetes findings are exploratory. The mechanism (mimic EPO's repair signal without erythropoiesis) is elegant but the receptor architecture is debated. In the U.S. it is investigational, sitting in FDA's 503A Category 3.
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Primary use case
Sarcoidosis SFN
Best human signal is in sarcoidosis-associated small fiber neuropathy, with symptom and corneal/skin nerve-fiber endpoints in Phase II. Grade B.
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Mechanism headline
EPO repair signal
Designed to mimic EPO's helix-B tissue-protective signaling without stimulating erythropoiesis. Grade P/C.
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Strongest evidence
Phase II / pilot
Human evidence exists but is small, mostly Phase II/pilot, and not approval-level. Grade B.
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Studied dose
4 mg SC daily
Most protocols used 4 mg SC once daily for 28 days or 12 weeks; early IV 2 mg in PK/pilot. Grade B/D.
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Key caution
Not "safe by design"
Don't assume safety because it's non-erythropoietic; long-term safety, malignancy, immune, pregnancy, and quality concerns are unresolved. Grade D.
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Negative trial
DME (primary)
The diabetic-macular-edema Phase II trial was safe but showed no mean improvement in core visual/anatomic endpoints. Grade B/C.
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US regulatory
Investigational
Not FDA-approved; on FDA's 503A bulk list as Category 3 (nominated without adequate support). Grade D.
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Pharmacokinetics
Minutes plasma
Short serum exposure (a few minutes after IV); 4 mg SC peak ~3 ng/mL — but downstream signaling outlasts plasma levels. Grade C.
02 · Mechanism of action
Borrowing EPO's repair half, leaving the red-cell half behind.
Erythropoietin does two things: it drives red-blood-cell production (via the classic EPOR homodimer) and it protects stressed tissue (via a distinct, non-hematopoietic receptor system). ARA-290 was engineered from EPO's helix-B surface to keep only the second — the tissue-protective signal — engaging what's called the innate repair receptor (IRR), proposed to involve EPOR plus the β-common receptor (CD131). Downstream, the themes are anti-inflammatory cytokine modulation, reduced microglial activation, anti-apoptotic signaling, and small-nerve-fiber repair. The mechanistic model is well-developed (Grade P/C); the human translation is strongest for nerve fibers (Grade B), and the receptor architecture itself is genuinely contested.
ARA-290 turns on a repair-like signal in stressed tissue without acting like full erythropoietin.
Clinical significance: The intended target is the non-hematopoietic tissue-protective receptor system — distinct from the EPOR homodimer that drives red-cell production. This is what lets it act without erythropoiesis.
Molecular detail: It is described as mimicking the 3D structure of EPO's helix-B surface and binding selectively to the innate repair receptor, believed to involve EPOR and βcR/CD131. The model is supported but debated — one study reported no direct extracellular EPOR–βc interaction under the tested conditions.
Grade C/P
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2 · Anti-inflammatory cytokine modulation
The peptide may reduce inflammatory signaling in injured or irritated tissue.
Clinical significance: Human sarcoidosis studies frame ARA-290 as an IRR activator that dampens inflammatory cytokine action and may reduce neuropathic symptoms. It is positioned as quieting inflammation rather than broadly suppressing immunity.
Molecular detail: Trial literature describes ARA-290 activating IRR signaling that can inhibit TNF-α and broader inflammatory cytokine cascades in injury models. Supported preclinically; human cytokine effects remain exploratory.
Grade B
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3 · Small-nerve-fiber repair / regeneration
ARA-290's strongest human story is nerve-pain improvement with small-fiber structural signals.
Clinical significance: Sarcoidosis-associated small-fiber-neuropathy trials assessed pain questionnaires, corneal confocal microscopy, and skin nerve-fiber measures. This is the indication with genuine human data.
Molecular detail: A 2017 sarcoidosis study reported increased corneal and skin small-nerve-fiber abundance, consistent with a possible disease-modifying effect — a structural signal, not just symptom relief. Still unconfirmed in large Phase III trials.
In animal pain models, ARA-290 appears to calm nerve-inflammation pathways.
Clinical significance: Preclinical neuropathic-pain models show reduced allodynia and suppression of the spinal microglial response — a proposed link between central inflammation and pain relief. Mechanistic basis for the analgesic effect.
Molecular detail: Swartjes et al. reported dose-dependent reduction in allodynia coupled to suppression of the spinal microglia response, suggesting a mechanistic link between suppressed central inflammation and relief of neuropathic pain. Preclinical; translation uncertain.
Grade C
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5 · Anti-apoptotic / cytoprotective signaling
ARA-290 may help stressed cells resist injury-related death signals.
Clinical significance: Kidney ischemia-reperfusion and other injury models suggest reduced apoptosis and inflammation — the basis for "organ-protection" research framing. Demonstrated in renal injury models.
Molecular detail: Helix-B surface peptide given after renal ischemia-reperfusion improved renal function/structure and reduced apoptosis through β-common-receptor-related mechanisms in animals. Downstream cascades include JAK2/STAT3, PI3K/Akt, and Bcl-2-family anti-apoptotic signaling. Preclinical.
In eye-disease research, ARA-290 was explored for diabetic retinal injury and edema.
Clinical significance: The diabetic-macular-edema Phase II trial used 4 mg SC daily for 12 weeks and found safety but no mean improvement in core visual/anatomic endpoints — an honest negative on the primary outcome, with only exploratory signals.
Molecular detail: The DME paper describes cibinetide as anti-apoptotic, anti-inflammatory, and anti-permeability, with preclinical diabetic-retinopathy models showing reduced vascular leakage/edema and neuroglial protection. Human efficacy not established; preclinical rationale exists.
L3 · Cascade
From tissue stress to nerve-fiber repair (proposed)
ARA-290 is unusual among research peptides in having a defensible human-study dosing anchor: most clinical work used 4 mg subcutaneous once daily, for 28 days in sarcoidosis neuropathy and 12 weeks in the diabetic-macular-edema trial, plus an early 2 mg IV PK reference. That said, there is no approved dosing protocol — these are study parameters, not prescribing instructions, and titration beyond the fixed dose is unvalidated. The compound is investigational, sitting in FDA's 503A Category 3. The calculator validates mg arithmetic only (working unit: mg).
Investigational · not FDA-approved · 503A Category 3
ARA-290/cibinetide is not FDA-approved for any indication. On FDA's 503A bulk drug substances list it is Category 3 — "nominated without adequate support" (list updated May 14, 2026). Historic orphan/Fast Track designations for sarcoidosis programs are not approvals. Dosing below is a research-model layer, not a clinical recommendation.
Short plasma PK, prolonged signaling
Serum exposure is brief; early literature notes 2 mg IV peak ~50 ng/mL with threshold activation around ~1 ng/mL, and the DME paper cites 4 mg SC peak ~3 ng/mL (~2.4 nM). Tmax, bioavailability, and clearance are not adequately established for page-grade use. CBC/hemoglobin monitoring is prudent despite the non-erythropoietic design.
Subcutaneous — fixed-dose clinical-study anchor
The route with genuine human data
Grade B
Study dose
4 mg SC once daily — used in sarcoidosis-associated neuropathy programs (28 days) and the DME trial (12 weeks).
Titration
No validated titration — fixed-dose model only. A speculative tolerability ladder (1 → 2 → 4 mg) is not trial-validated.
Cycle
28 days (sarcoidosis SFN); 12 weeks (DME). Washout not standardized; open-ended use not studied.
Reconstitution
16 mg vial + 4 mL diluent → 4 mg/mL; 4 mg dose = 1.0 mL = 100 U on a U-100 syringe.
Investigational. Avoid in pregnancy/lactation, active malignancy (unless protocol-supervised), uncontrolled inflammatory disease, or elite sport. Grade B (study anchor) · D (extrapolated titration).
Dose bands · study-anchored
Global dose-band table (research model, not prescribing)
Band
Fixed dose
≈ mg/kg @ 70 kg
Basis
Low exploratory
1 mg/day SC
0.014
Tolerability ladder only; not trial-validated
Moderate
2 mg/day SC
0.029
From early 2 mg IV PK context; SC 2 mg not validated
Study anchor
4 mg/day SC
0.057
Used in DME and sarcoidosis SFN programs
High
>4 mg/day
Not established
Do not define without protocol data
Weight-band · context only
Weight interpolation (context, not weight-based dosing)
Body weight
1 mg/day
2 mg/day
4 mg/day anchor
55 kg
0.018 mg/kg
0.036 mg/kg
0.073 mg/kg
65 kg
0.015 mg/kg
0.031 mg/kg
0.062 mg/kg
75 kg
0.013 mg/kg
0.027 mg/kg
0.053 mg/kg
85 kg
0.012 mg/kg
0.024 mg/kg
0.047 mg/kg
95 kg
0.011 mg/kg
0.021 mg/kg
0.042 mg/kg
105 kg
0.010 mg/kg
0.019 mg/kg
0.038 mg/kg
The DME paper raised that a fixed 4 mg dose may give lower peaks in severe obesity — a study interpretation, not a validated weight-adjusted algorithm.
Titration logic
Titration / safety decision logic
Trigger
Action
Rationale
Injection reaction / hypersensitivity
Hold; evaluate
Peptide-biologic exposure; limited long-term safety data
Hemoglobin/hematocrit rises
Hold; repeat CBC
Non-erythropoietic by design, but monitoring is prudent
BP elevation / thrombotic symptoms
Hard stop; urgent eval
EPO-family caution despite design
No response after 28 days
Do not auto-escalate beyond 4 mg
28-day trials used fixed dosing; high-dose strategy unvalidated
Pregnancy / lactation
Avoid unless formal protocol
Safety not established
Competitive athlete
Avoid / anti-doping review
WADA S2 risk
Biomarker scaffold
Monitoring scaffold
Marker
Purpose
Validated?
CBC / Hgb / Hct
Unwanted erythropoietic signal
No (prudent)
Neuropathic pain score
Symptom tracking
Partially (SFN studies)
Corneal confocal microscopy
Small-fiber abundance
Research-supported
Skin biopsy nerve density
Small-fiber structure
Research-supported
Blood pressure
Cardiovascular safety
No
HbA1c / glucose
Exploratory metabolic
No
Intravenous — early PK/pilot anchor only
Historical PK reference, not a protocol
Grade D
Reference
2 mg IV was referenced in early PK/pilot context — not an approved protocol.
Use
No validated escalation or maintenance; IV use should be protocol/manufacturer-controlled — do not infer home-use math.
Higher procedural risk; not appropriate outside a regulated research/clinical setting. Grade D.
IV PK note
What the early IV reference showed
Parameter
Value
IV dose (pilot)
2 mg
Peak level
~50 ng/mL
Threshold activation
~1 ng/mL
Oral
Not established
Grade D/P
Status
No credible human oral dosing protocol identified.
Reason
Peptide structure and short systemic exposure make oral bioavailability uncertain without specialized delivery.
Excluded from calculator. Grade D/P — not established.
Route reality
Only SC has real data
Route
Status
Subcutaneous
Human study anchor
IV
Early PK only
Oral
Not established
Intranasal
Not established
Grade D/P
Status
No validated human intranasal ARA-290 protocol identified.
Note
Excluded from calculator unless future literature emerges.
No basis. Grade D/P — not established.
Caution
No data exists
Question
Answer
Human protocol?
None
PK data?
None
Topical / ophthalmic
Not established
Grade D/P
Status
The human DME trial used systemic SC, not ophthalmic drops or intravitreal injection.
Note
No topical/ophthalmic local-delivery protocol established.
Excluded from calculator. Grade D/P — not established.
Clarification
DME study was systemic, not eye-drops
Misconception
Reality
"Eye-drops for DME"
Trial used 4 mg SC systemically
Intravitreal?
Not used
L2 · Reconstitution math (research only)
Reconstitution & Dose Calculator
This calculator validates concentration and draw-volume arithmetic only (working unit: mg) around the 4 mg SC study anchor. It is not a prescribing tool — ARA-290 is investigational and not FDA-approved (503A Category 3). Only the subcutaneous route has human-study precedent.
Concentration
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Draw volume
—
Units (U-100)
—
Doses/vial
—
Basis
—
04 · Combinations
Combinations — adjunct to standard care, not a replacement.
The combinations discussed around ARA-290 are framed as adjuncts to proven standard care, not validated regimens — and the honest theme is that none of them has been tested as a combination in humans. The recurring caution is real: as a disease-modifying small-fiber approach it might sit alongside conventional neuropathic-pain agents, but the pain-medication confounding is exactly why its trials watched for it; and in diabetes or eye disease it must never displace proven therapies (anti-VEGF, glycemic control). EPO-axis and tissue-repair biology also create theoretical concerns in malignancy and thrombotic history.
ARA-290 + Standard Neuropathic-Pain Care
Disease-modifying adjunct
ARA-290Pain agents
Studied conceptually as a disease-modifying small-fiber approach while conventional agents manage symptoms. A human ARA-290 SFN signal exists, but combination protocols are not validated. Watch for sedation/pain-med confounding — don't over-attribute response. Grade B (the SFN signal) · D (the combination itself).
Element
Role
Standard pain agents
Symptom control
ARA-290
Proposed disease-modifying
ARA-290 + Diabetes Standard Care
Exploratory metabolic
ARA-290Diabetes care
Exploratory metabolic and neuropathy signals in T2D/DME contexts — small human studies only. Monitor glucose; never replace proven diabetes therapy. A hypothesis-generating adjunct, not a glucose-lowering agent. Grade B/C (exploratory).
Signal
Status
HbA1c / metabolic
Exploratory (T2D study)
Neuropathy
Exploratory
ARA-290 + Ophthalmology Standard Care
DME · negative primary
ARA-290Anti-VEGF / laser
The DME trial did not show mean BCVA/CRT improvement overall, though it raised the question of further investigation in early/mild disease. Do not replace anti-VEGF, steroid, or laser standards. Grade C — the honest read is a negative primary endpoint.
Therapy
Role
Anti-VEGF / laser / steroid
Proven standard
ARA-290
Unproven for DME
ARA-290 + Anti-Inflammatory Disease Management
Mechanistic rationale
ARA-290Anti-inflammatory care
A mechanistic anti-inflammatory/tissue-repair rationale, mostly preclinical. IRR signaling can dampen inflammatory cytokines, but immunologic effects aren't fully mapped and no human combination data exist. Grade P/C.
Rationale
Status
Anti-inflammatory tissue repair
Preclinical/mechanistic
Immune mapping
Incomplete
Hard-constraint clinical note — Avoid casual stacking in active malignancy, pregnancy/lactation, uncontrolled autoimmune/inflammatory disease, significant thrombotic history, or competitive athletes unless under formal clinician/research oversight. Mechanism-derived tissue-repair and EPO-axis biology create theoretical concerns even though ARA-290 is designed to be non-erythropoietic — and none of the combinations above is a validated human regimen.
05 · Safety & contraindications
Well tolerated in small trials — but "non-erythropoietic" ≠ "proven safe".
In the small Phase II/pilot settings studied, ARA-290/cibinetide was generally well tolerated — the DME trial reported no serious adverse events and no anti-cibinetide antibodies in its small sample. That's reassuring as far as it goes, but it doesn't establish broad long-term safety, and the key honesty point is that "non-erythropoietic by design" is not the same as "proven safe." The meaningful risks are mechanistic (EPO-family and tissue-repair biology warrant caution in malignancy and thrombotic history even though red-cell stimulation is designed out), regulatory (investigational, gray-market quality variation), and the simple absence of long-term human safety data.
Safety signals & risks
Generally well tolerated in small trialsThe DME trial reported no serious adverse events and no anti-cibinetide antibodies in its small sample — reassuring but not definitive. Grade B/C.
Hematologic signal (monitor)Designed to avoid erythropoiesis, but EPO-derived biology warrants CBC monitoring. Grade D.
Thrombotic / cardiovascular cautionFull EPO raises erythropoiesis/thrombosis risk; ARA-290 is different, but caution remains. Grade D.
Immune modulationThe IRR/tissue-protective pathway may alter inflammatory signaling. Grade P/D.
Tumor-biology uncertaintyTissue-repair/anti-apoptotic signaling creates theoretical caution in active malignancy. Grade D.
Product-quality riskNon-approved compounded/research peptides vary in purity/sterility. Grade D.
Pregnancy / lactationNo adequate safety dataset. Grade D.
No long-term human dataSmall, short Phase II/pilot exposure does not establish chronic safety. Grade D.
Practical safety framework
"Well tolerated in small trials" has limits
The favorable tolerability came from small, short Phase II/pilot studies in selected patients. That supports short-term tolerability in those settings but says little about chronic use, broad populations, or rare events — so it's a reason for cautious optimism, not a safety guarantee.
EPO-family caution survives the redesign
ARA-290 is engineered to skip erythropoiesis, but it comes from EPO biology and engages tissue-repair/anti-apoptotic pathways. That's why CBC monitoring is prudent and active malignancy and significant thrombotic history are contraindications — the theoretical concern doesn't vanish because red-cell stimulation was designed out.
Investigational + gray market = quality risk
It is not FDA-approved (503A Category 3), so any material is unapproved and compounded/research-grade, with purity and sterility variation. Identity and quality should be confirmed, and gray-market product treated as unverified.
A real Phase II story — strongest in sarcoidosis nerve fibers.
ARA-290 has a genuinely better human evidence base than most research peptides — but it's concentrated in one place. Multiple small sarcoidosis-associated small-fiber-neuropathy studies (Heij 2012, Dahan 2013, Culver 2017) showed symptom improvement and — importantly — increased corneal/skin nerve-fiber abundance, a structural signal. The type-2-diabetes study (Brines 2015) suggested metabolic/neuropathy benefit, and the diabetic-macular-edema trial (Lois 2020) was safe but negative on its primary endpoints. Preclinical work spans neuropathic pain, renal ischemia-reperfusion, and retinal models. The honest grade: B for the sarcoidosis SFN signal, B/C for the exploratory/negative human work, C for preclinical — and not approval-level anywhere.
Sarcoidosis SFN · 2012
Grade B
Randomized double-blind pilot (n=22): improved SFN symptoms/QOL signals. Heij.
Open-label Phase II (n=9/8): safe, no mean BCVA/CRT improvement. Lois.
Type 2 diabetes
Exploratory
Suggested metabolic & neuropathy benefit; further study recommended. Brines 2015.
BHuman pilot · sarcoidosis SFN
Heij et al. (2012) — ARA-290 in sarcoidosis SFN (randomized, double-blind pilot)
A randomized, double-blind pilot (n=22) in sarcoidosis patients with small-fiber-neuropathy symptoms reported improved SFN-related symptom and quality-of-life signals, though pain decreased in both arms. The first controlled human signal — small, but a real randomized starting point.
Dahan et al. (2013) — symptoms & corneal nerve fiber density
A Phase II sarcoidosis-associated small-fiber-loss study using daily ARA-290 for 28 days reported improved symptoms and increased corneal nerve fiber density — moving from symptom report toward an objective structural endpoint.
Culver et al. (2017) — cibinetide increases nerve fiber abundance
A Phase II study in sarcoidosis-associated small-nerve-fiber loss and neuropathic pain, with cibinetide daily for 28 days, reported increased corneal and skin small-nerve-fiber abundance — the strongest structural evidence of a possible disease-modifying effect in this indication.
A small human study in type-2-diabetes patients with painful neuropathy suggested improvements in metabolic control (HbA1c, lipids) and neuropathic symptoms, recommending continued evaluation — an exploratory signal beyond sarcoidosis, not a confirmatory metabolic trial.
Lois et al. (2020) — cibinetide for DME (negative primary)
An open-label Phase II DME trial (9 recruited, 8 completed; 4 mg SC daily × 12 weeks) found cibinetide safe but with no mean improvement in BCVA or central retinal thickness — the primary endpoints. Only exploratory signals (NEI VFQ-25, tear production, diabetic control, albuminuria) and a relationship to baseline retinal thickness emerged. An honest negative on its main outcome.
Brines et al. (2008) — tissue-protective EPO-derived peptides
The foundational design paper defining short tissue-protective domains within erythropoietin, including the helix-B peptide rationale — the origin of the entire "split EPO's repair signal from its red-cell signal" concept that ARA-290 embodies.
Swartjes et al. (2011/2014) — long-term neuropathic-pain relief
Neuropathic-pain/allodynia models showed ARA-290 dose-dependently reduced allodynia coupled to suppression of the spinal microglia response — the preclinical mechanistic bridge between central inflammation and the analgesic effect, via β-common-receptor/microglia biology.
van Rijt / Yang et al. (2013) — renoprotection via β-common receptor
Renal ischemia-reperfusion models showed ARA-290/HBSP reduced inflammation and acute kidney injury and improved renal function, structure, and apoptosis through β-common-receptor-related mechanisms — the organ-protection evidence line, in animals renal IRI β-common receptor.
A study reporting no direct extracellular interaction between the erythropoietin receptor and β-common receptor under the tested conditions — included deliberately, because it tempers the tidy "IRR = EPOR + βcR heterocomplex" story: the receptor architecture is genuinely debated.
The Guide to Pharmacology ligand record describes cibinetide as mimicking EPO's helix-B surface 3D structure and binding selectively to the non-hematopoietic innate repair receptor — the curated pharmacology framing of the mechanism.
FDA 503A bulk drug substances — Cibinetide Category 3
FDA's 503A bulk drug substances list places cibinetide (ARA-290) in Category 3 — nominated without adequate support (updated May 14, 2026). The central US regulatory fact: it is investigational, not approved, and lacks adequate support for the compounding nomination.
GRADE summary — ARA-290/cibinetide has a stronger human evidence base than many research peptides, especially for sarcoidosis-associated small fiber neuropathy (Grade B — symptom and structural nerve-fiber signals across several small Phase II/pilot studies). But the evidence is small, early-phase, and non-approval-level: the type-2-diabetes data are exploratory (B/C), the DME trial was negative on its primary endpoints (B/C), and mechanism/organ-protection work is preclinical (C/P), with the receptor architecture itself debated. Positioning: "an investigational EPO-derived tissue-repair peptide with a genuine Phase II human signal in small fiber neuropathy, exploratory metabolic/retinal findings, short systemic PK with prolonged signaling, and unresolved long-term safety and regulatory status."
07 · Compare & contrast
ARA-290 in the EPO family.
ARA-290 is best understood against its parent biologic, erythropoietin, and its cousins in the tissue-protective EPO-derivative space. EPO itself is an approved drug — but for anemia, by stimulating red-cell production, with the thrombotic risk that entails. ARA-290 and carbamylated EPO (CEPO) are the attempts to keep EPO's tissue-protective signaling while dropping erythropoiesis. The table keeps the approval status honest: only full EPO/epoetin products are approved, and only for hematologic indications — the tissue-protective derivatives remain experimental.
Agent
Primary use positioning
Mechanism class
Evidence tier
Main route
Regulatory status
ARA-290 / cibinetide
Small fiber neuropathy, tissue repair, inflammatory injury
L1 · Consumer — ARA-290, also called cibinetide, is an experimental peptide designed to copy the repair-signaling part of erythropoietin without turning on red-blood-cell production. Its strongest human research signal is in small fiber neuropathy, especially sarcoidosis-related nerve pain and nerve-fiber loss. It is not FDA-approved, and "non-erythropoietic" does not automatically mean proven safe.
L2 · Clinical — Cibinetide is an 11-amino-acid, EPO-derived helix-B surface peptide investigated as a non-erythropoietic tissue-protective agent. Phase II/pilot studies suggest possible benefit in sarcoidosis-associated small fiber neuropathy, while diabetic-neuropathy/metabolic and diabetic-macular-edema findings remain exploratory or negative on primary endpoints. Most clinical work used 4 mg subcutaneous once daily; it is investigational (FDA 503A Category 3).
L3 · Research — ARA-290/pHBSP is modeled on the tissue-protective helix-B surface of erythropoietin and proposed to engage a non-hematopoietic innate repair receptor involving EPOR/β-common-receptor biology, though the receptor architecture remains debated. Downstream themes include anti-inflammatory cytokine modulation, reduced microglial activation, anti-apoptotic signaling, neurovascular protection, and small-fiber regenerative endpoints — with a short plasma half-life but prolonged downstream signaling.
08 · References & evidence
Source register.
Evidence grades reflect the strength of support for the specific claim cited, not the prestige of the journal. For ARA-290 the firmest sources are the small sarcoidosis-associated small-fiber-neuropathy Phase II/pilot studies (Grade B); the diabetic-macular-edema trial is graded honestly as B/C given its negative primary endpoints; preclinical pain/renal work and the design paper are C/P; and the receptor-architecture challenge is included to keep the mechanism honest. Regulatory and identity records (Grade D) anchor the investigational status. No source rises to approval-level (Grade A), which is the central fact about this peptide.