FDA Committee Rejects Capsaicin Patch for HIV Neuropathy Pain

An advisory committee of the U.S. Food and Drug Administration (FDA) last week unanimously voted against approval of a capsaicin patch for relief of HIV-related neuropathy pain, due to insufficient evidence of its effectiveness.

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Elevated Triglyceride Level Increases Likelihood of Peripheral Neuropathy

HIV positive people with higher blood triglyceride levels are more likely to develop peripheral sensory neuropathy, or nerve damage, according to a study described in the January 14, 2011 issue of AIDS. Investigators suggested that the relationship might be due to changes in mitochondria function associated with elevated triglycerides.

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IDSA 2011: Capsaicin Patch Reduces Pain Due to HIV-Associated Neuropathy

A patch containing 8% capsaicin -- a compound derived from chili peppers -- significantly relieved the pain of nerve damage related to HIV or its treatment, investigators reported at the 49th Annual Meeting of the Infectious Diseases Society of America (IDSA 2011) last month in Boston.

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AIDS 2008: Pregabalin vs Placebo for the Treatment of Painful HIV-associated Peripheral Neuropathy

Painful peripheral neuropathy remains a significant problem for many HIV/AIDS patients and there are few palliative or otherwise helpful therapies for this serious adverse event that may be associated with antiretroviral drug treatment, HIV infection itself, or both.

Pregabalin, an anti-epileptic drug, has previously demonstrated efficacy in several neuropathic pain syndromes. The FDA has approved Pfizer's pregabalin (Lyrica) for the treatment of fibromyalgia.

At the XVII International AIDS Conference last week in Mexico City, David Simpson of the Mount Sinai Medical Center in New York City presented results from the first trial to evaluate the efficacy, safety, and tolerability of pregabalin as a treatment for pain associated with HIV sensory neuropathy.

This randomized, double-blind, placebo-controlled, multicenter trial included 302 participants, 151 allocated to receive pregabalin and 151 to receive placebo. At baseline, the mean pain score was about 6.93 for the pregabalin arm and 6.72 for the placebo arm.

There were 4 phases: 1-2 week screening, 2-week double-blind dose-adjustment (150-600 mg/day taken twice-daily), 12-week double-blind maintenance, and 1-week tapering off. Overall average daily dosage of pregabalin was 385.7 mg/day.

The primary efficacy measure was mean pain score using an 11-point numeric rating scale completed daily by patients; weekly man pain score was a supplemental analysis.

Results

• At weeks 1 and 2, patients taking pregabalin had significantly greater improvements in mean pain score relative to placebo:

• Week 2: -1.92 vs 1.43; P = 0.0393.

• In an analysis of PGIC scores, more patients taking pregabalin said their condition had improved, and fewer said it had worsened (P = 0.0077):

• 13.3% and 25.4%, respectively, experienced "no change."

• The most common adverse events (AEs) in the pregabalin arm were somnolence (23.2% pregabalin vs 8.6% placebo) and dizziness (19.2% vs 10.6%, respectively).

• Seven patients (4.6%) in the pregabalin group and 2 patients (1.3%) in the placebo group discontinued because of treatment-related AEs.

Based on these findings, the study authors concluded, "Pregabalin and placebo were associated with substantial improvements in pain and PGIC, with no significant difference in endpoint mean pain score. Adverse events were consistent with the tolerability profile of pregabalin in other neuropathic pain clinical trials."

Mount Sinai Medical Center, New York, NY; Pfizer Global Pharmaceuticals, New York, NY.

8/15/08

Reference

DM Simpson, TK Murphy, E Durso-De Cruz, and others. A randomized, double-blind, placebo-controlled, multicenter trial of pregabalin vs placebo in the treatment of neuropathic pain associated with HIV neuropathy. XVII International AIDS Conference (AIDS 2008). August 3-8, 2008. Mexico City. Abstract THAB0301.

Peripheral Neuropathy Still Common, Capsaicin Patch Can Help

Nerve damage in the feet remains common among people with HIV in the ART era, though is often asymptomatic. A patch containing capsaicin -- derived from hot peppers -- relieved pain in people with HIV-associated neuropathy, researchers reported at a recent pain conference.

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