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These observational studies are included in a wide range of abstracts evaluating the use of the 8% capsaicin patch, presented at the World Congress on Pain in Milan, Italy (27-31 August 2012). When combined the abstracts on the 8% capsaicin patch presented at the conference provide data on over 2,500 treated patients. Observational studies are based on real-world practice and can give a naturalistic picture of treatment efficacy.
Efficacy reported in Scandinavian study
A Swedish observational study demonstrated the efficacy and tolerability of the 8% capsaicin patch in 211 non-diabetic patients with different peripheral neuropathic pain conditions, including partial peripheral nerve injury which can be caused by trauma or as the result of surgery.(1) The study found that:(1)
- Average pain intensity using the Numeric Pain Rating Scale (NPRS)* over the past 24 hours at baseline had a mean of 6.3 (SD 1.8).The mean change from baseline to 14 – 90 days post treatment (maximum pain reduction at any time point during this period) was -1.77 (SD 2.36), (95% CI. (-2.10 – -1.44)), P<0.001
- 29% of patients in the study reported that they felt their pain had decreased by 50% or more and 37% reported a 30% or more reduction in pain
- 51% of patients in the study reported some improvement in their overall status following treatment with the 8% capsaicin patch, using the Patient Global Impression of Change (PGIC) scale*
- 59% of patients asked for re-treatment with the 8% capsaicin patch and 14% of all patients did not seek re-treatment due to unsatisfactory pain relief
Professor Per Hansson, Specialist in Neurology and Pain Management, Karolinska University Hospital, Sweden, and lead investigator in the Swedish study comments, “Our data show that the 8% capsaicin patch can offer benefits for patients with peripheral neuropathic pain conditions, the majority of treated subjects reporting such pain after trauma or surgery.”
Quality of life and concomitant medication concerns addressed by Czech observational study
Neuropathic pain is a complex and difficult to treat disorder that can have a detrimental effect on a patient’s quality of life.(5,6) It is estimated that only around a third of patients receiving treatment for the condition achieve adequate pain relief.(7) A series of three posters presented at the World Congress on Pain showed that the 8% capsaicin patch could provide adequate pain relief with reduced need for other pain medications, and lead to improvements in quality of life for patients. The data were drawn from a prospective observational study of 258 patients with peripheral neuropathic pain who received treatment in the Czech Republic.(2,3,4)
The 8% capsaicin patch was shown to lead to statistically significant improvements in quality of life for patients who had previously been treated for their neuropathic pain. The mean values for quality of life among the patients in the study before treatment with the 8% capsaicin patch was 0.51 (SD 0.19) using the EQ-5D* questionnaire and 51.0 (SD 16.7) according to the visual analogue scale (VAS*). Three months after a single treatment with the 8% capsaicin patch, mean values for quality of life had significantly increased to 0.63 (SD 0.17, P<0.001) and 61.5 (SD 18.2, P<0.001) respectively.(2)
Use of the 8% capsaicin patch enables patients to reduce use of concomitant medications and lead to reduced hospital stay, potentially resulting in cost offset or savings. It was observed that 17.8% of patients who were already receiving treatment for their neuropathic pain were able to stop these medications after treatment with the capsaicin 8% patch. The key findings reported were:(3)
- In the previous 12 months, 96.9% of patients in the study had been on treatment for neuropathic pain
- Three months after a single treatment with the 8% capsaicin patch, the percentage of patients on other medication had decreased to 79.7%
- There was a 54.5% decrease in the probability of neuralgia-associated hospitalisation
- There was a 65.6% decrease in the duration of any stay in hospital (from 13.1 to 4.5 days)
The studies also confirmed that a single treatment with the 8% capsaicin patch led to a significant long-term reduction in pain. At three months 52.1% of patients reported pain relief of more than 30% on the NPRS* and 62.2% reported more than 30% reduction in pain, or a reduction of two degrees on the NPRS.(4)
“New treatment approaches should be welcomed in neuropathic pain. Our study showed there are high unmet needs in this patient population and the 8% capsaicin patch offers an effective treatment for peripheral neuropathic pain, providing long-term pain relief and improved quality of life,” comments Dr Tomáš Doležal, Institute of Health Economics and Technology Assessment, Prague, Czech Republic and investigator in the Czech observational study, “It is unusual for an observational study such as this to better the results seen in randomised controlled clinical trials, so these findings, along with data showing a reduction in healthcare resource utilisation, further demonstrate the real life cost-effectiveness of the 8% capsaicin patch.”
Exactly how many people suffer from neuropathic pain is not known but estimates of the prevalence of neuropathic pain range from 3% to as high as 8% according to a UK study.(8,9) Estimates vary considerably because of differences in the way neuropathic pain is defined, the way in which the condition is assessed and the selection of patients.(10)
The 8% capsaicin patch uses a synthetic form of capsaicin, the substance found in chilli peppers that gives them their ‘heat’, to change the way the pain-sensing nerves work in the area of skin affected.(11) The efficacy and safety of the 8% capsaicin patch have been investigated in a comprehensive clinical trial programme involving 1,327 patients who received at least one application.(12) Pain relief following application of the 8% capsaicin patch can take up to two weeks to take full effect and can last for up to 12 weeks following a single application.(12) Significant reductions in pain have been achieved with the 8% capsaicin patch when used alone or in combination with other treatments for pain.(12)
The most commonly reported side effects with the 8% capsaicin patch are transient and self-limiting application site reactions such as pain and erythema that tend to be mild to moderate in intensity.(12)
*About the rating scales used in these studies
PGIC is a short questionnaire completed by the patient following treatment ranking their perception of any change in activity limitations, symptoms, emotions and overall quality of life related to their painful condition on a 7-point scale from -3 (very much worse) to +3 (very much improved).
NPRS is a numeric 11-point rating scale to allow patients to describe the severity of their pain at a given point in time.
EQ-5D is a questionnaire used to assess any improvements in quality of life for patients.
VAS is a visual scale used to measure levels of pain by asking patients to define their pain by indicating a position along a continuous line between two end-points.
References
- Hansson P et al. A Swedish prospective observational multicenter study to evaluate efficacy and safety in patients with peripheral neuropathic pain receiving their first Qutenza™ treatment.” Presented at World Congress on Pain, Milan, August 2012 [Abstract PT 422]
- Dolezal T et al. High concentration capsaicin patch improves quality of life in patients with neuropathic non-diabetic pain. Presented at World Congress on Pain, Milan, August 2012 [Abstract PH 124]
- Vocelka M et al. Lower consumption of concomitant pain medication and other resource use after administration of 8% capsaicin patch: Results of the observational study. Presented at World Congress on Pain, Milan, August 2012 [Abstract PH 135]
- Klimes J et al. High concentration (8%) of capsaicin patch: Effectiveness in real clinical practice for treatment of neuropathic pain of non-diabetic etiology in the Czech Republic. Presented at World Congress on Pain, Milan, August 2012 [Abstract PH 107]
- Gálvez R et al. Cross-sectional evaluation of patient functioning and health-related quality of life in patient with neuropathic pain under standard care conditions. Eur J of Pain 2007;3:244-55
- Smith B et al. Health and quality of life associated with chronic pain of predominantly neuropathic origin in the community. Clin J Pain 2007;23:143–9
- Jensen T et al. Pharmacology and treatment of neuropathic pains. Curr Opin Neurol 2009;22:467-474
- Gilron I et al. Neuropathic pain: a practical guide for the clinician. CMAJ 2006;175(3):265-75
- Mailis Gagnon A et al. Systematic review of the prevalence of neuropathic pain. Eur J Pain 2007;11 (Suppl. 1):S202-S203 [Abstract No. 457]
- National Institute for Health and Clinical Excellence (NICE) Neuropathic Pain: The pharmacological management of neuropathic pain in adults in non-specialist settings. March 2010. Available from: http://www.nice.org.uk/nicemedia/live/12948/47949/47949.pdf. Last accessed: July 2012
- Knotkova H et al. Capsaicin (TRPV1 agonist) therapy for pain relief: Farewell or revival? Clin J Pain 2008;24(2):142-154
- Qutenza (Capsaicin) EPAR. Available from: http://www.ema.europa.eu/docs/en_GB/document_library/EPAR_-_Product_Information/human/000909/WC500040453.pdf Last accessed: July 2012
