ARA-290 (Cibinetide)

ARA-290 (also called Cibinetide) is a synthetic peptide made of 11 amino acids, derived from the hormone erythropoietin (EPO). The active substance selectively activates the Innate Repair Receptor (IRR), inhibits inflammation, and promotes tissue repair and nerve regeneration, without triggering the blood-forming effects of EPO. In several phase 2 clinical trials, ARA-290 was studied for the treatment of neuropathic pain, sarcoidosis-associated small fiber neuropathy, and type 2 diabetes.

How is ARA-290 used and dosed?

In clinical protocols, ARA-290 is primarily given by subcutaneous injection (s.c.) or intravenously (i.v.), with daily subcutaneous administration becoming the preferred method in later phase 2 studies. Clinical data exist only for parenteral injections; nasal, oral, or topical forms of ARA-290 have not been studied in clinical trials.

• Intravenous (i.v.): Patients in the first sarcoidosis pilot study received 2 mg of ARA-290 three times a week for 4 weeks [1].
• Subcutaneous (s.c.): In the diabetes study, patients self-injected 4 mg of ARA-290 daily for 28 days; in the subsequent dose-finding study on sarcoidosis, they self-administered 1 mg, 2 mg, or 4 mg subcutaneously each day [2, 3].

In the later clinical studies, patients administered ARA-290 themselves using standardized prefilled syringes. On the gray market, however, the substance circulates as lyophilized peptide powder in vials, which users reconstitute with bacteriostatic water (BAC water) and inject subcutaneously. This home use is an unproven practice without the backing of controlled clinical trials.

How does reconstitution and dosage calculation work for ARA-290?

Reconstituting ARA-290 requires precisely dissolving the lyophilized powder in sterile BAC water, since no standardized finished pharmaceutical products are commercially available for this unapproved substance. The following calculation illustrates mathematically how the doses of 2 mg to 4 mg s.c. used in phase 2 clinical trials are drawn from a 5-mg vial.

Example calculation (based on the clinical study dose of 4 mg s.c.):

If the vial size or the volume of solvent differs, you need to calculate the peptide concentration beforehand. The guides on mixing and storing peptides explain the method of sterile reconstitution in detail. This model calculation serves only to help you understand clinical protocols and is not medical dosing advice.

How does ARA-290 work in the body? Mechanism of action and receptors

ARA-290 acts as a selective agonist at the Innate Repair Receptor (IRR), a heteroreceptor made up of the classical erythropoietin receptor and the CD131 subunit (beta-common receptor). When ARA-290 binds to the IRR, it triggers a tissue-protective signaling cascade that blocks proinflammatory pathways, limits cellular damage, and kick-starts regenerative processes in the tissue [4].

The key therapeutic advantage of ARA-290 over native erythropoietin (EPO) is that it completely avoids stimulating erythropoiesis. Because ARA-290 does not promote the formation of red blood cells, hematological side effects such as an uncontrolled rise in hematocrit, increased blood viscosity, and the associated risk of thrombosis do not occur [4].

At the cellular and structural level, the peptide ARA-290 produces the following effects through the IRR:

• Anti-inflammatory: Inhibits proinflammatory cytokines and downregulates activated immune cells [5]
• Cytoprotective: Protects various tissue cells from stress-induced cell death (apoptosis) [5]
• Neuroprotective: Promotes the survival and functional regeneration of small, unmyelinated nerve fibers [1, 2]
• Metabolic: Improves insulin sensitivity and optimizes the lipid profile in metabolic dysfunction [2]

What do clinical studies on ARA-290 and nerve regeneration show?

Phase 2 clinical trials show that ARA-290 significantly reduces symptoms in small fiber neuropathy and produces a measurable increase in nerve fiber density, with good short-term tolerability. The clinical development of this peptide was led by the biopharmaceutical company Araim Pharmaceuticals.

ARA-290 in sarcoidosis-associated small fiber neuropathy

In a randomized, placebo-controlled phase 2 pilot study with 22 sarcoidosis patients, giving 2 mg of ARA-290 i.v. (three times a week for 4 weeks) led to a significant improvement in the Small Fiber Neuropathy Screening List (SFNSL) score compared to placebo (p < 0.05). Along with pain relief, functional parameters improved without any relevant safety concerns [1].

The follow-up dose-finding study (NCT02039687) tested 1 mg, 2 mg, and 4 mg of ARA-290 subcutaneously over 28 days in sarcoidosis patients. The key result was that ARA-290 significantly increased corneal nerve fiber density, providing objective evidence of structural regeneration of small nerve fibers [3].

ARA-290 in type 2 diabetes and neuropathic pain

In type 2 diabetes patients with painful diabetic neuropathy, taking 4 mg of ARA-290 s.c. daily for 28 days reduced neuropathic pain on the PainDetect questionnaire and improved HbA1c levels and blood lipid values. In patients with initially reduced corneal nerve fiber density, a significant increase in nerve fibers was seen during the subsequent 28-day follow-up, with no substance-specific safety issues [2].

Preclinical evidence and animal research

Preclinical animal models document tissue-protective effects of ARA-290 in peripheral nerve lesions [6], experimental autoimmune neuritis, cerebral ischemia, and cisplatin-induced nephrotoxicity [5]. These animal data confirm the cell-protective mechanism at the IRR, but they cannot be applied to humans without reservation.

What risks and side effects are known for ARA-290?

In phase 2 studies over 4 weeks, ARA-290 showed few side effects and no statistically significant differences from placebo in terms of adverse events [1, 2, 3]. Since it does not induce erythropoiesis, the typical EPO risk of elevated hematocrit with a tendency to thrombosis does not occur; however, the evidence base is limited to small groups (22-66 subjects).

The following safety aspects and risk factors should be considered when evaluating ARA-290:

• Short-term safety: Good tolerability and side effect rates at placebo level in controlled 28-day studies [1, 2]
• Long-term safety: No evidence on long-term effects over periods of several months or years
• Small study populations: Limited statistical power to detect rare adverse drug reactions due to small case numbers
• Gray market risks: Contamination hazards, dosing errors, and lack of sterility from unregulated sources - the vendor radar offers criteria for checking labs and suppliers

What is still unknown about ARA-290?

• No phase 3 studies and no regulatory approval from authorities such as the FDA or EMA
• No controlled long-term data on safety of use beyond 8 weeks
• No officially validated standard dosage outside specific study protocols
• No clinical data on use in pregnant women, pediatric patients, or people with liver or kidney impairment
• Insufficient data on potential interactions with other medications
• Unknown durability of the regenerative nerve effects and metabolic improvements after treatment ends

Assessment and conclusion: How should the peptide ARA-290 be evaluated?

ARA-290 (Cibinetide) is one of the best-studied peptide candidates for targeted tissue protection and nerve regeneration, with controlled phase 2 data showing an objective increase in corneal nerve fibers. Despite these regenerative effects, the peptide remains an unapproved investigational drug without standardized pharmaceutical safety for use.

Further scientific profiles of experimental peptides for regeneration and tissue healing are available in the peptide library for detailed evidence comparisons.