Predictors of Response in Patients with Postherpetic Neuralgia and HIV-Associated Neuropathy Treated with the 8% Capsaicin Patch (Qutenza).

OBJECTIVES:Qutenza is a high-dose capsaicin patch used to relieve neuropathic pain from postherpetic neuralgia (PHN) and HIV-associated neuropathy (HIV-AN). In clinical studies, some patients had a dramatic response to the capsaicin patch. Our objective was to determine the baseline characteristics of patients who best benefit from capsaicin patch treatment.METHODS:We conducted a meta-analysis of 6 completed randomized and controlled Qutenza studies by pooling individual patient data. Sustained response was defined as>50% decrease in the mean pain intensity from baseline to weeks 2 to 12, and Complete Response as an average pain intensity score≤1 during weeks 2 to 12. Logistic regression was used to identify predictors of response and Complete Response, and subgroups of patients who respond best to the capsaicin patch.RESULTS:Baseline pain intensity score (BPIS)≤4 was a predictor of Sustained and Complete Response in PHN and HIV-AN patients; absence of allodynia and presence of hypoesthesia, and a McGill Pain Questionnaire (MPQ) sensory score <22 were predictors of Sustained Response in PHN patients; female sex was a predictor of Sustained and Complete Response in HIV-AN patients. Thus, characteristics associated with the highest chance of responding to the capsaicin patch were, for PHN, BPIS≤4, MPQ sensory score≤22, absence of allodynia, and presence of hypoesthesia; for HIV-AN, they were female sex and BPIS≤4. Patients with these characteristics had a statistically significantly greater chance of responding to the capsaicin patch than other patients.DISCUSSION:We identified subpopulations of PHN and HIV-AN patients likely to benefit from the capsaicin patch.