A novel approach to identify responder subgroups and predictors of response to low‐ and high‐dose capsaicin patches in postherpetic neuralgia

作者：Chris H. Martini, Ashraf Yassen, Axel Krebs‐Brown, Paul Passier, Malcolm Stoker, Erik Olofsen, Albert Dahan · 发表于：European Journal of Pain · 年份：2013 · DOI：10.1002/j.1532-2149.2013.00329.x · 被引用次数：57 · 研究领域：Pain Mechanisms and Treatments、Herpesvirus Infections and Treatments、Ion Channels and Receptors

BACKGROUND: Treatment of chronic pain conditions is commonly assessed at specific endpoints at preset times during or after treatment by analysis of the total study population. An alternative approach is the identification of specific patient subgroups characterized by differential response patterns in their analgesic response and to determine the presence of significant predictors of effect. METHODS: Data from four double-blind, randomized controlled trials on the efficacy of topical capsaicin 8% (Qutenza) versus an active control (capsaicin 0.04%) in patients with postherpetic neuropathic pain were combined. Longitudinal pharmacodynamic, mixture and covariate analyses were performed on the pooled dataset. RESULTS: Data from 1248 patients treated with Qutenza (n = 722) or topical low-dose capsaicin 0.04% (n = 526) were successfully analysed. Five distinct response subgroups were detected with different treatment efficacies, including a group of non-responders, a group showing partial analgesic effect and a group showing full analgesic effect. Active control and Qutenza had similar response profiles, but the proportional distribution of patients among the five response groups was in favour of Qutenza, with 40% less non-responders and 25% more patients showing a full analgesic response. For Qutenza, important predictors of efficacy were efficacy of lidocaine pretreatment and greater pretreatment pain score variability. CONCLUSIONS: The analyses indicate the existence of differ...