NGX-4010, Capsaicin 8% Patch, Effective for Postherpetic Neuralgia in Older Population

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AUSTIN, TX Data presented at the American Pain Society's 30th Annual Scientific Meeting demonstrated that NGX-4010, a capsaicin 8% patch significantly reduces pain in older patients with postherpetic neuralgia (PHN), a debilitating condition characterized by persistent pain following the healing of a herpes zoster rash. The risk of developing herpes zoster is 50% in people over 85 years old, and age is the predominant factor in developing PHN, with a 21% prevalence rate in people aged 80-841. Traditional therapies for PHN do not always provide satisfactory pain relief and may not be suitable for older patients.2-4

Gordon Irving, MD, from Swedish Pain Center, Seattle, WA, and colleagues investigated integrated data from four randomized, double-blind, 12-week controlled PHN studies of NGX-4010, evaluating efficacy and safety in the older population subgroup (median age 80 years). The analysis included 305 patients (≥73 years) receiving a single 60-minute treatment with NGX-4010 and 277 patients receiving a low-dose (0.04%) capsaicin control patch. Endpoints included the mean percentage change from baseline to Weeks 2-8 in “average pain for the past 24 hours” Numeric Pain Rating Scale (NPRS) score and the proportion of patients with ≥30%, ≥50% or ≥2 units decrease in NPRS scores. Adverse events (AEs) were also evaluated.

The investigators found that NGX-4010 decreased pain associated with PHN in the older patient subpopulation. The NGX-4010-treated group experienced a mean percentage NPRS score reduction from baseline of 25.8% compared with 17.1% in the control group (P=0.0005); 35.4% of NGX-4010-treated group achieved ≥30% reduction in NPRS scores vs. 26% for control, P=0.0164; 23.6% had a reduction of ≥50% in NPRS scores vs. 12.6% for control, P=0.0009; and 33.8% had a decrease of ≥2 units vs. 28.4% for control, P=0.0002 all during Weeks 2–8.

Similar results were obtained during Weeks 2–12. The most common AEs in the older NGX-4010 patients were capsaicin-related application site erythema, pain, papules and pruritus (>5%) and their incidence and severity was similar to the younger NGX-4010 patients. Most of these AEs were mild to moderate and self-limited.

Dr. Irving et al. concluded that the data demonstrate that a single application of NGX-4010 can produce significant pain reduction for 12 weeks in the older patients with PHN with similar adverse event profiles compared to the younger population. This was study supported by NeurogesX.

References

1.      Johnson RW, et al. Postherpetic neuralgia in the elderly, Int J Clin Pract. 2009;Sept; 63(9): 1386-1391.

2.      Sampathkumar P, et al. Herpes zoster (shingles) and postherpetic neuralgia. Mayo Clinic Proc. 2009;Mar; 84(3):274-280.

3.      O'Connor A, et al. Treatment of neuropathic pain: An overview of recent guidelines. Am J Med. 122(10 supp); 2009: S22-S32.

4.      Harden N, et al. Unmet needs in the management of neuropathic pain. J Pain Symptom Manage. 2003; May; 25(5 supp): S1 2-7.

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