Capsaicin Trials Reveal Moderately Positive Results For Nerve Pain

Today's post from clinicalpainadvisor.com (see link below) reveals the results of recent trials of the capsaicin (chili-based) patch Qutenza in relation to neuropathic pain. Now capsaicin is one of those treatments that regularly returns to the neuropathy forums on the internet but mostly without conclusive results. The results here can also hardly be called 'conclusive' but they do indicate that there is benefit to be had from capsaicin patches, if applied properly. That's the problem: it's a controversial treatment because it carries the risk of potential burn issues and is both tricky to use and needs medical supervision (especially with the 8% versions that are pretty strong). Alternatives include capsaicin creams but they do tend to be messy and less effective than the patches. If you are considering trying capsaicin patches, please talk to your doctor first before ordering them on the internet. Hopefully your insurance will cover them anyway so it's always best to go through the official channels.
 

Capsaicin 8% Patch Effective on Nondiabetic Peripheral Neuropathic Pain
Christin Melton, ELS May 03, 2017 
 
The patch used in the study is approved in the United States for postherpetic neuralgia and in Europe for PNP arising from any etiology.

Results from the ASCEND study recently published in BioMed Central Neurology indicate that an 8% capsaicin patch is effective in relieving peripheral neuropathic pain resulting from a wide range of etiologies.1

Peripheral neuropathic pain (PNP) may arise from several medical conditions and is commonly encountered in clinical practice.2 Conditions including diabetes, cancer and cancer treatments, traumatic nerve injury/entrapment syndromes, and infections such as herpes zoster virus (HZV) or human immunodeficiency virus (HIV) are known etiologies of PNP.1,2 Many patients with PNP are treated with oral nonsteroidal anti-inflammatory drugs (NSAIDs) despite a lack of evidence of their efficacy in relieving neuropathic pain.3 A phase 4 open-label study, ASCEND (Clinicaltrials.gov ID NCT01737294) sought to determine whether a high-dose capsaicin patch (8%; QUTENZA™) was effective on several measures of PNP in a real-world setting.1 The patch used in the study is approved in the United States for postherpetic neuralgia (PHN) and in Europe for PNP arising from any etiology.

ASCEND, which was an observational study conducted from February 2012 to August 2014, included 429 adults from 7 European countries who had non-diabetic PNP, with etiologies including HZV, HIV, back injury or inflammation, cancer, and surgery or trauma. Some participants had newly diagnosed PNP, whereas others had previously received 1 or more treatments for PNP. The patches were prescribed as part of routine clinical practice, with patients receiving up to 4 capsaicin patches per treatment. Patches were applied for 30 minutes to the feet and for 60 minutes at other sites. Subsequent capsaicin treatments could be prescribed every 90 days.

The study's primary end point consisted of follow-up, which was conducted by phone or at the prescribing clinic at weeks 2 and 8. Additional follow-up sessions were conducted at weeks 12, 26, 39, and 52. At each time point, patients were asked to rate their pain intensity over the past 24 hours and over the past 7 days using a 0 to 10 numeric pain rating scale (NPRS). In addition, health-related quality of life (HR-QOL) and perceived changes in health were evaluated.

Between the first capsaicin patch application and follow-up at weeks 2 and 8, mean NPRS scores decreased 26.6% (95% confidence interval (CI: 23.6, 29.62; n = 412). Almost half of patients had at least a 30% reduction in pain at weeks 2 (44.4% reduction; n=183) and 8 (49.1% reduction; n=79). In some patients, pain relief (as indicated by ≥50% reduction in pain scores) occurred as early as the second week after treatment (26.2% of patients; n=108). Improvement was similar in patients with PNP resulting from PHN, neuropathic back pain, postoperative or posttraumatic neuropathic pain, and other causes.

Median time for first re-treatment was 191 days, which was administered to 43.1% of study participants (n=181). In the 16.7% (n=70) of patients who received a third dose, a median of 301 days elapsed between first and second re-treatments. The capsaicin 8% patch showed evidence of long-term effectiveness, with an overall 37% reduction in NPRS scores between baseline and week 52. The investigators noted that “patients in the primary stage of treatment or with short duration of disease had the greatest pain reduction, suggesting that patients with PNP may benefit from early treatment with the capsaicin 8% patch.” Sustained improvement in HR-QOL and in patients' self-perception of health status were also observed. At week 12, 61.0% of patients (n=224/367), indicated their health had improved.

The capsaicin 8% patch was well tolerated. More than 92% of patients completed at least 90% of the suggested patch applications. Only 11% of patients experienced an adverse event, the most common of which were site reactions. The researchers concluded that “the capsaicin 8% patch may benefit patients who have inadequate pain relief from systemic therapies or for those suffering intolerable systematic side effects.” 

Summary and Clinical Applicability

The ASCEND study observed meaningful decreases in pain and improvement in health-related quality of life in patients with PNP with wide-ranging etiologies. In many patients, the capsaicin 8% patch showed long-term effectiveness and good tolerability. In the United States, the capsaicin 8% patch is only approved for PHN. However, the current study indicates that the patch may be an effective option when first-line therapies for PNP are ineffective or not tolerated. 

Limitations and Disclosures

The ASCEND study is limited by the fact that it was an open-label observational study vs a randomized controlled trial.

The study was sponsored by Astellas Pharma Europe Ltd., which manufactures the Qutenza 8% capsaicin patch used in the study.

Several study investigators and individuals who designed the study were Astellas employees. However, the researchers who recruited and treated study participants had no relevant disclosures. Astellas funded the data analyses and medical writing and editing services for the study.


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Neuropathic Pain Complexity Requires Thoughtful Approach and Combination of Interventions
Central Neuropathic Pain Syndromes
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References
Mankowski C, Poole CD, Ernault E, et al. Effectiveness of the capsaicin 8% patch in the management of peripheral neuropathic pain in European clinical practice: the ASCEND study. BMC Neurol. 2017;17(1):80.
Jay GW, Barkin RL. Neuropathic pain: etiology, pathophysiology, mechanisms, and evaluations. Dis Mon. 2014;60(1):6-47.
Moore RA, Chi CC, WIffen PJ, Derry S, Rice AS. Oral nonsteroidal anti-inflammatory drugs for neuropathic pain. Cochrane Database Syst Rev. 2015;(10):CD010902.

http://www.clinicalpainadvisor.com/neuropathic-pain/capsaicin-patch-for-non-diabetic-peripheral-neuropathic-pain/article/654496/