Is the Capsaicin 179 mg (8% w/w) Cutaneous Patch an Appropriate Treatment Option for Older Patients with Peripheral Neuropathic Pain?

Abstract

Introduction

Capsaicin 179 mg (8% weight per weight) cutaneous patch (“capsaicin patch”) is a recommended topical treatment for peripheral neuropathic pain (PNP). In older patients, topical treatments may be preferred over systemic treatments, but data specific to the older population are scarce.

Methods

We conducted pooled analyses of multiple clinical trials to evaluate efficacy and safety of capsaicin patch in older patients. The analysis of efficacy included four randomized, double-blind, 12-week studies with similar trial design comparing a single treatment of capsaicin 179 mg cutaneous patch vs low-dose control patch in post-herpetic neuralgia. For the safety evaluation, data were pooled from 18 interventional studies in which capsaicin patch was used in PNP with varying etiologies.

Results

Capsaicin patch had similar analgesic efficacy in elderly (n=582) and non-elderly patients (n=545) in terms of change from baseline to 2–12 weeks in the 11-point numeric pain rating scale (NPRS) score for average pain over the previous 24 hours. In both age groups, decrease in NPRS score was significantly greater with capsaicin patch vs control. Older patients treated with capsaicin patch were significantly more likely than those in the control group to achieve responder status (ie mean decrease in NPRS score from baseline to week 2–12 of at least 30% or ≥2 points): 36.1% vs 27.1% (odds ratio [OR] [95% CI] 1.52 [1.06, 2.18]; P=0.0231) and 33.1% vs 20.9% (OR [95% CI] 1.90 [1.30, 2.78]; P=0.0009) for active treatment vs control group, respectively. Similar proportions of non-elderly patients (n=2,311) and elderly patients (n=537) treated with capsaicin patch experienced treatment-emergent adverse events (TEAEs) (81.6% and 78.1%, respectively) and serious TEAEs (8.2% and 7.2%), with application-site reactions the most common TEAEs in both groups.

Conclusion

The capsaicin patch was equally efficacious and well tolerated in older patients as in younger patients.

Plain language summary

Peripheral neuropathic pain is a common challenge among the elderly, yet effective treatments for this age group remain underexplored. This research focuses on the use of a high-concentration capsaicin patch, a specialized treatment for this type of pain. The patch, which is applied directly to the affected skin area, has been shown to reduce pain significantly for up to 12 weeks. This analysis of multiple clinical trials showed that the high-concentration capsaicin patch significantly reduced pain intensity and was well tolerated in older patients with peripheral neuropathic pain.

Keywords:

• capsaicin patch
• elderly
• peripheral neuropathic pain
• pooled analysis
• topical treatment

Abbreviations

AE, adverse event; ANCOVA, analysis of covariance; BOCF, baseline observation carried forward; CI, confidence interval; HIV-PN, human immunodeficiency virus infection-related peripheral neuropathy; IMMPACT, Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials; LOCF, last observation carried forward; LS, least squares; MOP, μ-opioid peptide; NOP, nociceptin/orphanin FQ peptide; NPRS, numeric pain rating scale; OR, odds ratio; pDPN, painful diabetic peripheral neuropathy; PHN, post-herpetic neuralgia; PNP, peripheral neuropathic pain; SE, standard error; SoC, standard of care; TEAE, treatment-emergent adverse event.

Data Sharing Statement

Grünenthal will endeavor to share clinical information from applicable studies, ie clinical study reports and clinical data from interventional clinical trials, with suitably qualified scientific and medical researchers as necessary for conducting legitimate research. Access requests must be submitted through ClinicalStudyDataRequest.com. Further information is available at https://www.grunenthal.com/en/science/clinical-trials/data-sharing-clinical-trials.

Analysis Preregistration

The clinical trials included in the pooled analyses were preregistered in independent institutional registries. The pooled analyses were preplanned, but the analysis plan was not preregistered.

Acknowledgments

Medical writing support was provided by NexGen Healthcare Communications.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

Gisèle Pickering has received consultancy fees from Grünenthal, Mylan, MundiPharma, and Sanofi. Sylvia Engelen, Maria Stupar, and Mariëlle Eerdekens are employees of Grünenthal GmbH. Hervé Ganry has received consultancy fees from Grünenthal GmbH.

Additional information

Funding

This work was supported by Grünenthal GmbH. Grünenthal GmbH was involved across all stages of the publication.