What it is
ARA-290 is a synthetic peptide of eleven amino acids modelled on a region of the erythropoietin molecule that sits away from the part responsible for making red blood cells. It is also called cibinetide, and it was developed by Araim Pharmaceuticals. Because it is built from the tissue-protective face of erythropoietin rather than the blood-forming one, researchers describe it as non-hematopoietic, meaning it is not expected to raise red blood cell counts the way erythropoietin itself does. [3]
Its proposed target is the innate repair receptor, a pairing of the erythropoietin receptor with a second protein called the beta common receptor that appears on injured or inflamed tissue rather than on healthy tissue. That selectivity is the whole idea behind the compound, and it is also the part of the story that comes from the group that named the receptor, so it is worth reading with that in mind. [6]
What researchers study it for
- Small fiber neuropathy in sarcoidosis This is the anchor of the human record. In a randomized, double-blind pilot of 22 people with sarcoidosis, four weeks of intravenous ARA-290 given three times weekly improved small fiber neuropathy symptom scores more than placebo, along with the pain and physical functioning dimensions of a standard quality of life questionnaire. [1]
- Corneal nerve fiber density A second blinded, placebo-controlled trial used a different regimen, twenty-eight days of daily subcutaneous dosing, and reported improvement in neuropathic symptom scores together with an increase in corneal small nerve fiber density, cutaneous temperature sensitivity, and six-minute walk distance. [2] The corneal measurement is the most objective finding anywhere in this literature, because it is a count of nerve fibers rather than a questionnaire score.
- Macrophage activation and transplanted tissue In a mouse islet transplant model with supporting cell culture work, ARA-290 was associated with protection of transplanted islets from cytokine-driven damage and with reduced secretion of several inflammatory signalling proteins from macrophages. [4] This is animal and in vitro work, and it is the clearest support for the anti-inflammatory side of the mechanism.
- Diabetic nerve damage in animal models In diabetic mice, ARA-290 reduced established nerve fiber dystrophy in sympathetic ganglia by roughly 55 to 74 percent without changing blood glucose measures, which is the point of the experiment since it separates the nerve effect from glucose control. The same study found no effect on neuron number or on ongoing neuron loss. [5]
- Glucose handling, in rats only Four weeks of daily dosing in a rat model of type 2 diabetes was associated with lower plasma glucose in weeks three and four, a fall in glycated hemoglobin of about 20 percent, and improved beta cell glucose oxidation, with no change in hematocrit. [7] This is a rat study. No human metabolic result has been published, and that gap matters more than the rat data does.
Research context
ARA-290 is unusual among research peptides in having genuine registered human trials rather than an animal-only record, and it is worth saying plainly that this is a real strength. It is also worth saying, in the same breath, that both published human trials were small and that neither the compound nor the programme has produced an approved drug in any country. The 2012 study enrolled 22 people and its own authors called it a pilot, and the two trials used different routes and schedules, intravenous three times weekly in the first and daily subcutaneous in the second, so they are not one result repeated twice. [1] [2] A frequently cited 2014 paper in Expert Opinion on Investigational Drugs is a review of those same two trials rather than a third one, which is an easy mistake to make when counting up the evidence.
Two registered trials are worth naming because they frame what has and has not been tested in people. NCT02039687 covered corneal nerve fiber density and neuropathic symptoms in sarcoidosis, and NCT01933529 was a Phase II study at Karolinska in prediabetes and drug-naive type 2 diabetes with primary completion in June 2014. As far as this review could establish, the Karolinska metabolic trial has never been published, so anyone reading a vendor page that pairs the glucose findings with the phrase "human trial" should check which species is being described. [7] The mechanism literature has a similar wrinkle worth knowing about, since the main review of the innate repair receptor was written by the researchers who proposed the receptor and ran the sarcoidosis trials. [6] That is not disqualifying, it just means the field has not yet had much independent assessment.
Typical research parameters
| Parameter | Typical range |
|---|---|
| Common vial sizes | 2 mg and 5 mg are the usual research supplier formats |
| Supplied as | Lyophilized (freeze-dried) powder |
| Storage | Lyophilized powder refrigerated at 2 to 8 degrees Celsius, or frozen for long-term storage |
| Stability | Reconstituted peptide is handled refrigerated and used within a short window; repeated freeze and thaw cycles are avoided |
| Administration studied | Intravenous three times weekly in the 2012 pilot, daily subcutaneous in the 2013 trial [1] [2] |
| Purity to look for | ≥98% by HPLC; third-party certificate of analysis recommended |
References
- [1] Heij L, Niesters M, Swartjes M, et al. 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(1):1430-6. PubMed ↗
- [2] Dahan A, Dunne A, Swartjes M, et al. ARA 290 improves symptoms in patients with sarcoidosis-associated small nerve fiber loss and increases corneal nerve fiber density. Molecular Medicine. 2013;19. PubMed ↗
- [3] van Velzen M, Heij L, Niesters M, et al. ARA 290 for treatment of small fiber neuropathy in sarcoidosis. Expert Opinion on Investigational Drugs. 2014;23(4):541-50. Review of the two published trials rather than independent trial data. PubMed ↗
- [4] Watanabe M, Lundgren T, Saito Y, et al. A nonhematopoietic erythropoietin analogue, ARA 290, inhibits macrophage activation and prevents damage to transplanted islets. Transplantation. 2016;100(3):554-562. PubMed ↗
- [5] Schmidt RE, Green KG, Feng D, et al. Effect of insulin and an erythropoietin-derived peptide (ARA290) on established neuritic dystrophy and neuronopathy in Akita (Ins2 Akita) diabetic mouse sympathetic ganglia. Experimental Neurology. 2011. PubMed ↗
- [6] Dahan A, Brines M, Niesters M, Cerami A, van Velzen M. Targeting the innate repair receptor to treat neuropathy. PAIN Reports. 2016;1(1):e566. Written by researchers who proposed the receptor and ran the sarcoidosis trials. PubMed ↗
- [7] Watanabe M, Lundgren T, Saito Y, et al. ARA290 improves insulin release and glucose tolerance in type 2 diabetic Goto-Kakizaki rats. Molecular Medicine. 2016;22. Animal study. PubMed ↗