Compound profile
ARA-290 (Cibinetide)
Limited human dataAlso known as: Cibinetide · EPO helix-B surface peptide
An 11-amino-acid peptide engineered from a non-erythropoietic region of erythropoietin, designed to activate tissue-repair signaling without stimulating red blood cell production. Studied in phase 2 human trials for small-fiber neuropathy, one of the more clinically tested "tissue protective" peptides.
Overview
ARA-290, known by its generic drug name cibinetide, is an 11-amino-acid synthetic peptide engineered from a specific surface region of erythropoietin (EPO), the hormone best known for stimulating red blood cell production. The idea behind it is a kind of molecular separation: EPO has two distinct effects, one that boosts red blood cell counts and a separate one that protects and helps repair tissue, and researchers wanted a way to get the tissue-protective effect without the blood-related one.
That separation was engineered by Michael Brines and Anthony Cerami at Araim Pharmaceuticals, who identified the specific three-dimensional surface region of EPO, the helix-B surface domain, responsible for its tissue-protective and anti-inflammatory signaling, distinct from the part of the molecule that drives red blood cell production. ARA-290 reproduces that helix-B region as a standalone peptide, deliberately built to avoid triggering the classical EPO receptor pathway tied to red blood cell stimulation.
The peptide moved further into human clinical development than most peptides in this category, reaching phase 2 randomized controlled trials in specific neuropathy conditions. However, Araim Pharmaceuticals closed before phase 3 trials could be completed, so despite meaningful phase 2 data, ARA-290/cibinetide has not been approved by any regulatory agency and its development has effectively stalled.
Mechanism (plain language)
Activates the "innate repair receptor" (a complex of the erythropoietin receptor and the beta-common receptor subunit) to reduce inflammation and support nerve-fiber regeneration, while deliberately avoiding the erythropoietin receptor pathway that drives red blood cell production.
How it works
ARA-290 works through a receptor complex researchers call the innate repair receptor, a combination of the standard EPO receptor and a separate protein called the beta-common receptor subunit (also known as CD131). This is different from the classical EPO receptor pathway alone, which is what drives red blood cell production. By engaging this combined receptor complex rather than the classical EPO pathway, ARA-290 is designed to trigger anti-inflammatory, anti-apoptotic (meaning it protects cells from a specific form of programmed cell death), and tissue-repair signaling, without meaningfully raising red blood cell mass.
This distinction matters clinically because elevating red blood cell counts, as full EPO or its analogues do, carries its own risks, including increased blood clotting risk, which is why EPO-based drugs are tightly regulated and monitored. ARA-290's design intent was to keep the tissue-protective and nerve-supportive signaling that researchers observed with EPO in some contexts, while deliberately engineering out the blood-related effect, making it a more targeted tool for studying nerve repair and inflammation specifically rather than a general EPO substitute.
What research suggests
A randomized, placebo-controlled phase 2 trial in sarcoidosis-associated small-fiber neuropathy reported significant improvement in neuropathic symptoms and an objective increase in corneal nerve fiber density after 28 days of dosing; a separate exploratory trial reported improved metabolic markers in painful diabetic neuropathy.
Reported benefits
What studies, case reports, and the research literature describe, not guaranteed outcomes. The trials behind these findings are in the studies below.
Improved symptoms in small-fiber neuropathy
A randomized, placebo-controlled phase 2 trial in sarcoidosis-associated small-fiber neuropathy reported significant improvement in neuropathic symptoms after 28 days of dosing.
Objective nerve fiber regeneration signal
The same trial reported an objective increase in corneal nerve fiber density, a measurable marker of small nerve fiber health, not just a symptom score.
Metabolic marker improvements in diabetic neuropathy
A separate exploratory trial in painful diabetic neuropathy reported improved metabolic markers alongside neuropathy-related outcomes.
Tissue protection without red blood cell stimulation
By design and in trial data, ARA-290 has not been associated with the blood-count changes seen with classical EPO therapy, supporting its intended mechanism.
Uncertainties & risks
Trials are small (dozens of patients) and in specific neuropathy populations, not general recovery or performance contexts. The company developing it (Araim Pharmaceuticals) closed before phase 3 trials were completed, so development has stalled and no approved product exists.
ARA-290's human trials, while more rigorous than what exists for many research peptides, were still small, involving dozens of patients rather than the hundreds or thousands typical of pivotal drug trials, and were conducted in specific, narrowly defined neuropathy populations, sarcoidosis-associated small-fiber neuropathy and painful diabetic neuropathy, not in general recovery or performance contexts that some online discussion extrapolates toward. The more significant issue is that Araim Pharmaceuticals, the company developing cibinetide, closed before phase 3 confirmatory trials could be completed. That means the drug's development effectively stalled at the phase 2 stage despite having orphan drug designation and encouraging early results, and no new drug application has been filed with the FDA or any comparable agency. There is currently no path to an approved product, and anyone encountering ARA-290 as a research chemical should understand they are working with a peptide whose most rigorous supporting data comes from trials in a very specific patient population, with commercial development on hold.
Primary sources
Secondary citations for verification. Prefer the STACKD summary above for context before opening these.