Phase 2b study of ARC-4558 for painful diabetic neuropathy (PDN)

Arcion Therapeutics announced positive results from a Phase 2b, double-blind, randomized, placebo-controlled clinical trial of ARC-4558 (clonidine HCl 0.1% topical gel) in patients with painful diabetic neuropathy (PDN). The study included an adaptive trial design and enrolled a total of 180 adult patients with PDN. Patients in the study applied ARC-4558 0.1% gel or placebo to the affected area three times a day (3.9 mg clonidine per day) for a 12-week treatment period. Patients were able to continue taking a stable dose of their existing pain medications. The primary endpoint of the study related to the change in pain at week 12 compared to baseline measured by the numerical pain rating scale (NPRS).  

The study results demonstrated ARC-4558 to be most effective in reducing pain in patients with evidence of preserved nociceptors in the skin.  In patients with at least minimal nociceptor function, ARC-4558 was significantly more effective in reducing pain than placebo (p<0.05). The significance of the response increased with higher levels of nociceptors in the subject’s skin (p<0.005). ARC-4558 did not demonstrate efficacy in subjects lacking evidence of preserved nociceptor function.  

ARC-4558 is a 0.1% gel formulation of clonidine hydrochloride (HCL) for topical administration to the painful area in order to manage the neuropathic pain associated with PDN.  Topical clonidine, through its agonist effects on alpha2-adrenergic receptors, is believed to reduce pain in PDN via local actions on the nociceptors that innervate the affected skin.

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