Topical RM191A gel for chronic peripheral neuropathic pain: randomized, double-blind, placebo-controlled, crossover pilot study.

Introduction: Current pharmacotherapy options for neuropathic pain (NPP) are limited. RM191A is a novel copper-amino acid complex that mimics superoxide dismutase and has anecdotal evidence for fast-onset analgesia. The aim of this pilot randomized clinical trial (RCT) was to evaluate the safety and efficacy of a topical gel containing RM191A compared with placebo in adults with moderate-to-severe chronic peripheral NPP. Materials and methods: This single-site study was conducted at an Australian pain clinic. Eligible patients were randomized to receive either active or placebo gel, applied four times daily to the painful site for 3 days, followed by a 4-day washout and crossover to the other gel. Co-primary outcomes were changes in the Numerical Pain Rating Scale (NPRS) scores for average pain from baseline to Days 1 and 3. Secondary outcomes included safety/tolerability and neuropathic pain characteristics. Results: Twenty-seven participants (14 males, 13 females, mean age 67 ± 15 years) were screened, with 25 proceeding to randomization and 24 completing both treatment periods. No first-order ( Discussion: This small pilot RCT found that 3 days of RM191A gel modestly reduced chronic peripheral neuropathic pain. The NNT of 8 compares favorably with topical lidocaine (14.5) and is similar to duloxetine (7.4) and gabapentinoids (8.9). Larger, longer studies in well-defined neuropathic pain populations are warranted. Clinical Trial Registration: ANZCTRN 12617000206325. https://www.anzctr.org.au/.