High concentration capsaicin for treatment of peripheral neuropathic pain: effect on somatosensory symptoms and identification of treatment responders

Abstract

Background:

Pain is usually assessed by spontaneous pain ratings. Time-dependent (brief attacks) or evoked (allodynia) phenomena, common in neuropathic pain, are not captured. To evaluate the overall effectiveness of a treatment, improvement of all sensory symptoms should be measured. Since the pattern of sensory abnormalities might hint at the underlying mechanisms of pain, this baseline information may aid in predicting the treatment effect. Data on sensory neuropathic abnormalities (painDETECT questionnaire) were analyzed aiming to (1) evaluate the frequency of neuropathic symptoms in different peripheral neuropathic pain syndromes, (2) assess the effect of capsaicin 8% patch on neuropathic symptoms and (3) identify treatment responders based on baseline values.

Methods:

Data analysis of a prospective 12 week non-interventional trial in peripheral neuropathic pain treated with capsaicin 8% cutaneous patch. Average pain intensity during the past 24 hours, pain descriptors and qualities of neuropathic pain were assessed to characterize the patients’ sensory symptoms at baseline and to document changes.

Results:

(1) Characteristic symptoms of neuropathic pain were present in all peripheral neuropathic pain syndromes, but frequencies varied in the individual syndromes. (2) Topical capsaicin 8% treatment significantly reduced the overall pain intensity and resulted in a reduction of sensory abnormalities. (3) Short disease duration predicted a better treatment effect. High painDETECT scores, the presence of burning and pressure-evoked pain were weakly associated with treatment response.

Conclusions:

Topical capsaicin 8% treatment effectively reduced sensory abnormalities in peripheral neuropathic pain. The association of sensory symptoms and treatment response aids in understanding the mechanism of action of high concentration capsaicin. It is, however, not possible to use sensory symptom patterns to predict treatment response to capsaicin on an individual level.

Limitations:

Completion of painDETECT was optional and therefore data was not available for all patients. Further studies for confirmation of these results are needed.

Keywords::

• Capsaicin 8% patch
• PainDETECT questionnaire
• Pain duration
• Peripheral neuropathic pain
• Sensory symptoms
• Treatment response

Transparency

Declaration of funding

The trial was funded by Astellas Pharma GmbH, Munich, Germany. Study concept, study design, operational conduct, data analysis and review of the manuscript were undertaken by Marie-Luise Heskamp, Medical Department, Astellas Pharma GmbH.

Declaration of financial/other relationships

J.H. has received speaking fees or research support from Pfizer, Grünenthal, Astellas and Genzyme. S.H. has received speaking fees or research support from Grünenthal, Astellas and Genzyme. M.-L.S.H. is an employee of Astellas Pharma GmbH. C.G.M. has received honoraria as consultant for Astellas, Bionorica and Mundipharma, and has participated in speakers bureaus of Allergan, Astellas, Grünenthal, Janssen and Pfizer. University Hospital Erlangen received financial support from Astellas Pharma to fund the investigation. R.B. is a member of the IMI Europain consortium, IMI ‘Europain’ collaboration and industry members of this are: AstraZeneca, Pfizer, Esteve, UCB-Pharma, Sanofi Aventis, Grünenthal, Eli Lilly and Boehringer Ingelheim. R.B. has received grants from the German Federal Ministry of Education and Research (BMBF) (German Research Network on Neuropathic Pain, NoPain system biology) and from the German Research Foundation (DFG). He has received speaking fees from Pfizer, Genzyme, Grünenthal, Mundipharma, Sanofi Pasteur, Medtronic, Eisai, UCB BioSciences, Lilly, Boehringer Ingelheim, Astellas, Desitin, Teva Pharma and Bayer-Schering. He has been a consultant to Pfizer, Genzyme, Grünenthal, Mundipharma, Allergan, Sanofi Pasteur, Medtronic, Eisai, UCB BioSciences, Lilly, Boehringer Ingelheim, Astellas, Novartis, Bristol-Myers Squibb, Biogenidec and AstraZeneca.

CMRO peer reviewers may have received honoraria for their review work. The peer reviewers on this manuscript have disclosed that they have no relevant financial relationships.

Acknowledgments

We thank factum (Gesellschaft für Statistik, wissenschaftliche Information und Kommunikation GmbH, Offenbach, Germany) for the statistical analysis as well as Petra Stadler (Omniconsult, Zweibrücken, Germany) and Matt Burchill (Astellas Pharma GmbH, Germany) for editing of language, and Matti Förster for his valuable comments. Special thanks go to the 161 investigators who have contributed to this study.

Notes

*Qutenza is a registered trade name of Astellas Pharma Europe BV, The Netherlands

^†EMLA is a registered trade name of AstraZeneca GmbH, Karlskoga, Sweden