Treatments for peripheral neuropathic pain compared

The first study to compare the 8% capsaicin patch with pregabalin as a treatment for peripheral neuropathic pain begins, with enrolment of the first patient.

The study, called ELEVATE, aims to evaluate the efficacy and safety of the topical 8% capsaicin patch against pregabalin, an oral therapy which is widely used as first-line treatment for peripheral neuropathic pain.¹ The earliest results are expected in 2014.

Conventional therapies for peripheral neuropathic pain can be restricted by factors such as systemic side effects, drug-drug interactions, slow onset of action, the need for titration and multiple daily dosing.^2,3,4

The 8% capsaicin patch is designed to act locally on the affected area and has not been associated with the systemic side effects such as sedation and dizziness that may be experienced with other treatments.^2,3,5 The study is designed to provide results which will help patients receive treatment which best balances pain relief with tolerability of treatment and the ability to return to daily activities.

Associate Professor Maija Haanpää, a Consultant in Pain Management at the Helsinki University Central Hospital, Finland and the lead investigator in the ELEVATE study comments: “It is important to perform head-to-head comparative studies in the field of neuropathic pain. This study may also provide information about the symptom profiles that are most likely to respond to the different treatments since the NPSI* questionnaire is used to assess the characteristics of pain and other sensory symptoms.”

The study aims to enrol 526 patients from approximately 100 centres in 23 countries across eastern and western Europe, including the UK, Germany, France, Italy, Spain, Sweden, Finland, Russia, Romania and Bulgaria.¹

Peripheral neuropathic pain is caused by lesion or disease to the peripheral somatosensory nervous system. The somatosensory system is a diverse sensory system composed of the receptors and processing centres to provide information about touch or pressure, temperature, body position and pain.

The nerve damage that can lead to peripheral neuropathic pain can happen as a result of a range of different diseases, medications or traumatic injuries. Exactly how many people suffer from neuropathic pain is not known but estimates for the percentage of the population affected typically range from 1 to 2%, however some sources estimate prevalence to be as high as 8%.^6,7

It is a complex and difficult to treat disorder that can have a detrimental effect on a patient’s quality of life.^8,9 Studies suggest that, at present, only around a third of patients receiving treatment for neuropathic pain achieve adequate pain relief.¹⁰

The 8% capsaicin patch uses a synthetic form of capsaicin, the substance found in chilli peppers which gives them their ‘heat’, to change the way these 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.⁵

Pain relief following application of the 8% capsaicin patch can take up to two weeks to take full effect and can be maintained for up to twelve weeks following a single application.⁵ Significant reductions in pain have been achieved with the capsaicin patch when used alone or in combination with other treatments for pain.⁵

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.⁵

*The Neuropathic Pain Symptom Inventory (NPSI) is a self-questionnaire specifically designed to evaluate the different symptoms of neuropathic pain.

References

1. EU Clinical Trials Register: https://www.clinicaltrialsregister.eu/ctr-search/search?query=2011-005872-41 Last accessed: May 2012
2. Backonja M et al. NGX-4010, a high-concentration capsaicin patch, for the treatment of postherpetic neuralgia: a randomised, double-blind study. Lancet Neurol 2008;7(12):1106-12
3. Simpson DM et al. Controlled trial of high-concentration capsaicin patch for treatment of painful HIV neuropathy. Neurology 2008;70(24):2305-13
4. O’Connor AB et al. Treatment of neuropathic pain: an overview of recent guidelines. Am J Med 2009;122:S22-32
5. Qutenza (Capsaicin) EPAR. Available from: http://www.ema.europa.eu/docs/en_GB/document_library/EPAR_-_Product_Information/human/000909/WC500040453.pdf Last accessed: April 2012
6. 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: April 2012
7. 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]
8. 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
9. 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
10. Jensen T et al. Pharmacology and treatment of neuropathic pains. Current Opinion in Neurology 2009;22:467-474
11. Knotkova H et al. Capsaicin (TRPV1 agonist) therapy for pain relief: Farewell or revival? Clin J Pain 2008;24(2):142-154
12. Anand P et al. Topical capsacin for pain management: therapeutic potential and mechanisms of action of the new high-concentration capsaicin 8% patch. Br J Anaesth 2011;107(4):490-502