Efficacy of Pregabalin for Peripheral Neuropathic Pain: Results of an 8-Week, Flexible-Dose, Double-Blind, Placebo-Controlled Study Conducted in China

Background: Topical capsaicin therapy may be of benefit in providing pain relief in patients with peripheral neuropathy. Objectives: To investigate the efficacy and safety of 0.625% (50 µg/cm2 ) and 1.25% (100 µg/cm2 ) capsaicin patches (CPs) compared to conventional 0.075% capsaicin cream or placebo patches in patients suffering from peripheral neuropathy. Study Design: Early Phase II, multi-center, randomized, semi-double-blind, and placebocontrolled clinical trial. Setting: Two medical college teaching hospitals. Methods: Sixty patients were randomized to the 0.625% CP, 1.25% CP, placebo-controlled patch, or 0.075% capsaicin cream. The primary efficacy endpoint was the mean difference in the change of daily numerical rating scale (NRS) pain score. Secondary endpoints included values for the Daily Sleep Interference Scale, the percentage of patients achieving a ≥ 30% or ≥ 50% reduction in pain, and data for Global Impression Change (GIC) and EQ-5D. Results: Patients treated with the 0.625% CP and 0.075% capsaicin cream showed statistically significant improvements in pain after 6-weeks of test drug application. Daily sleep disorder scores were improved only for those patients applying the 0.075% capsaicin cream. For patient-derived GIC scores, the majority (11 of 12) of patients in the 0.625% CP group reported that their pain was improved. For the safety evaluation, 2 severe adverse events were reported for the 0.075% capsaicin cream group only. Repetitive patch application was related to minor skin problems such as a burning sensation, erythema, pruritus, and vesicles in 28 patients (46.67%). Limitations: The small sample size and relatively high dropout rates. Conclusion: Our data indicate that the 0.625% CP may prove to be an effective and safe alternative with which to treat patients with peripheral neuropathy and could replace the high concentration (8%) CP. Further studies are now needed to definitively establish efficacy. Key words: Capsaicin, patch, CP, topical capsaicin, neuropathic pain, peripheral neuropathic pain, PNP, high concentration CP

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One Year Follow-up of a Randomized, Double-Blind, Placebo-Controlled Trial of Percutaneous Peripheral Nerve Stimulation for Chronic Neuropathic Pain Following Amputation

Neurosurgery ◽

10.1093/neuros/nyz310_144 ◽

2019 ◽

Vol 66 (Supplement_1) ◽

Author(s):

Joshua M Rosenow ◽

Christopher Gilmore ◽

Brian M Ilfeld ◽

Sean Li ◽

Mehul J Desai ◽

...

Keyword(s):

Neuropathic Pain ◽

Pain Relief ◽

Peripheral Nerve ◽

Nerve Stimulation ◽

Peripheral Nerve Stimulation ◽

Pain Interference ◽

Controlled Study ◽

Double Blind ◽

Double Blind Placebo

Abstract INTRODUCTION Over 85% of patients experience residual limb (RLP) and/or phantom limb (PLP) pain following amputation. Peripheral nerve stimulation (PNS) is a non-opioid approach to relieve postamputation neuropathic pain. A recent multicenter, randomized, double-blind, placebo-controlled study using a novel percutaneous PNS system demonstrated clinically and statistically significant improvements in pain and pain interference with PNS compared to placebo (Gilmore et al, 2019). This work presents prospective 1-yr follow-up to assess durability of pain relief and functional improvements. METHODS Over 85% of patients experience residual limb (RLP) and/or phantom limb (PLP) pain following amputation. Peripheral nerve stimulation (PNS) is a non-opioid approach to relieve post-amputation neuropathic pain. A recent multicenter, randomized, double-blind, placebo-controlled study using a novel percutaneous PNS system demonstrated clinically and statistically significant improvements in pain and pain interference with PNS compared to placebo (Gilmore et al, 2019). This work presents prospective one-year follow-up to assess durability of pain relief and functional improvements. RESULTS A significantly greater proportion of subjects who completed the 12-mo visit reported = 50% pain relief on the BPI-SF (5/8, 63%; average pain relief = 73% among responders) compared to the placebo group at the time of crossover (0/14, 0%, P = .003; average pain relief = 23%). A majority of subjects also reported = 50% reductions in pain interference at 12 mo (5/8, 63%). Two of 13 (15%) subjects in the placebo group reported sustained improvements in pain interference (P = .06). Average reduction in pain interference among responders in the PNS group was 87%. CONCLUSION This work suggests that PNS delivered over 60 d may provide clinically significant and enduring pain relief, enabling improved function and potentially reducing the need for a permanently implanted system.

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