Effect of Capsaicin (8%) Topical System on Sensory Function in Patients With Diabetic Peripheral Neuropathy: Analysis of the <scp>PACE</scp> Study

INTRODUCTION/AIMS: High-concentration capsaicin topical system (HCCTS) is an established treatment for painful diabetic peripheral neuropathy (PDPN). The PACE primary analysis showed that HCCTS + standard of care (SOC) was not associated with deterioration in nerve function compared with SOC alone over 52 weeks. This post hoc analysis of PACE evaluated sensory function changes in the feet after repeated 30-min HCCTS treatments + SOC. METHODS: Sensory function was assessed using the Brief Sensory Pain Examination (BSPE) alongside the Norfolk Quality of Life-Diabetic Neuropathy (QOL-DN) questionnaire and its small- and large-fiber subscales. Analysis 1 descriptively assessed shifts in sensory test results over 12 months in patients receiving one to seven 30-min HCCTS treatments + SOC. Analysis 2 statistically compared mean sensory scores over 12 months with HCCTS + SOC versus SOC alone in patients with below-normal baseline sensory function. RESULTS: Analysis 1 (n = 156) showed that repeated HCCTS treatments were associated with shifts from below-normal to normal sensory function at Month 12 in 21.1%, 26.4%, and 22.8% of heat, cold, and sharp tests, respectively. Analysis 2 (HCCTS n = 88; SOC n = 89) demonstrated significant improvements with HCCTS + SOC versus SOC alone in BSPE heat (p = 0.009), sharp (p = 0.048), vibration (p = 0.008), and Norfolk QOL-DN total (p < 0.001) and large-fiber subscale scores (p < 0.001). DISCUSSION: Repeated 30-min HCCTS treatments + SOC improved peripheral sensory function over 12 months in PDPN patients with baseline sensory deficits. If confirmed in dedicated trials, sensory improvements may reduce diabetic foot complications by restoring protective sensation, possibly via neuroregenerative effects of HCCTS reported elsewhere.