Controlled Trial of High-Concentration Capsaicin Patch for Treatment of Painful HIV Neuropathy
July 1, 2008
There are limited effective treatments for the painful condition HIV-associated distal sensory polyneuropathy (HIV-DSP). Capsaicin desensitizes cutaneous nociceptors resulting in reduced pain. The authors reported on a placebo-controlled study of a high-concentration capsaicin dermal patch (NGX-4010) for the treatment of painful HIV-DSP.
The double-blind multicenter study randomized 307 patients with painful HIV-DSP to receive NGX-4010 or control, a low-concentration capsaicin patch. A topical anesthetic was applied, and then participants received NGX-4010 or control to painful areas on the feet once for 30, 60 or 90 minutes. Percent change in Numeric Pain Rating Scale (NPRS) from baseline in mean "average pain for past 24 hours" from weeks two to 12 was the primary efficacy endpoint.
For this time period, a single NGX-4010 application resulted in a mean pain reduction of 22.8 percent, compared to a 10.7 percent reduction for controls (p=0.0026). Following a transient treatment-related pain increase, pain was lessened; significant improvement was apparent by week two and continued throughout the controlled 12-week observation period. For NGX-4010, mean pain reductions in the 30, 60, and 90-minute groups were 27.7 percent, 15.9 percent, and 24.7 percent (p=0.0007, 0.287, and 0.0046 vs. control). One-third of patients receiving NGX-4010 reported = 30 percent pain decrease from baseline, compared to 18 percent of controls (p=0.0092). Self-limited, mild-to-moderate local skin reactions were commonly reported.
"A single NGX-4010 application was safe and provided at least 12 weeks of pain reduction in patients with [HIV-DSP]," the authors concluded. "These results suggest that NGX-4010 could provide a promising new treatment for painful HIV neuropathy."
6.2008; Vol. 70: P. 2305-2313; David M. Simpson, MD; Stephen Brown, MD; Jeffrey Tobias, MD; the NGX-4010 C107 Study Group