AUSTIN, TX—Results of a study presented at the American Pain Society’s 30th Annual Scientific Meeting found that the prescription-strength capsaicin 8% patch, NGX-4010 (Qutenza), indicated for the management of postherpetic neuralgia (PHN), provided 3 months of relief, with the largest degree of relief for burning pain, shooting pain, or numbness.
Patients rated their pain from 0–100 at screening and Week 12 on the 12-item Neuropathic Pain Questionnaire (NPQ), which was developed to differentiate neuropathic from non-neuropathic pain. Study author Miroslav Backonja, MD, from Lifetree Clinical Research, Salt Lake City, UT, and colleagues also compared mean percent change from baseline to Weeks 2–12 in “average pain for the past 24 hours” Numeric Pain Rating Scale (NPRS) score between treatment groups using a gender-stratified ANCOVA model with baseline pain as the covariate.
Integrated data from 384 patients who received a single, one-hour, localized NGX-4010 application demonstrated a mean percentage reduction from baseline to Weeks 2–12 in NPRS score of -30.8% compared with -21.1% in 327 patients who received a single 30-, 60- or 90-minute 0.04% capsaicin control patch application (P<0.0001).
Compared with baseline screening, patients in the NGX-4010 group experienced more reduction on all NPQ items at Week 12 vs. controls, but only those with burning pain, shooting pain, or numbness had significantly different reductions. At Week 12, median percent reduction from baseline in burning pain was -40% in NGX-4010-treated patients vs. -27% in controls (P=0.0046); -50% vs. -29% (P=0.0124), for shooting pain; and -54% vs. -33% (P=0.0147), for numbness.
Patients treated with NGX-4010 achieved complete resolution for almost each NPQ item compared with control, but the agent was statistically significant only in patients with burning pain and tingling pain. At Week 12, percentage of patients with resolution for burning pain was 29% for NGX-4010 and 16% for control (P=0.0019) and for tingling pain, 34% vs. 24% (P=0.0466), respectively.
Dr. Backonja et al. conclude that NGX-4010 can provide 3 months of PHN relief and that the differential effect of NGX-4010 on several components of the NPQ may guide further studies on pathophysiology and treatment of pain associated with PHN.