Analgesic effectiveness of capsaicin 8% cutaneous patch for the treatment of chronic postsurgical or post-traumatic neuropathic pain: a randomized placebo controlled study in children aged 12 to 17-y

The primary objective of this study is to demonstrate the **analgesic effectiveness** of a capsaicin 8% cutaneous patch in managing chronic postsurgical or post-traumatic neuropathic pain in children aged 12 to 17 years. The clinical relevance of this objective lies in addressing the significant challenge of managing chronic neuropathic pain in pediatric patients, which can severely impact quality of life and daily functioning. The improvement in the Neuropathic Pain Symptom Inventory (NPSI) score will be assessed before the initial application of capsaicin or placebo and again four months later, following one or two applications.

Secondary objectives include: - Evaluation of tolerance and safety during application and in the subsequent days. - Assessment of analgesic effectiveness using the NPSI. - Analysis of NPSI subscores. - Evaluation of functional improvement using the Functional Disability Inventory (FDI). - Investigation of the impact of topical capsaicin treatment on the use of concomitant pain medication and non-pharmacologic pain therapies.

The clinical trial focuses on evaluating the **analgesic effectiveness** of a capsaicin 8% cutaneous patch in managing **chronic post-surgical or post-traumatic neuropathic pain** in a pediatric population. The study population comprises children aged 12 to 17 years, including both male and female participants. The trial does not involve a vulnerable population. Participants are required to have persistent neuropathic pain for more than 32 months following surgery or trauma, despite receiving treatment according to standard recommendations. The pain must be localized in a nerve territory associated with the surgery or trauma and meet specific diagnostic criteria, such as a DN4 score of 3/7 or 4/10. The sponsor has not provided information regarding the total number of participants. The trial population was selected based on these criteria, ensuring that all participants are treated, surveyed, and followed up in an identified investigating center of the study. No specific lifestyle considerations, such as diet or physical activity, are mentioned as part of the trial's focus.

The clinical trial is designed to evaluate the **analgesic effectiveness** of a **capsaicin** 8% cutaneous patch in children aged 12 to 17 years suffering from chronic postsurgical or post-traumatic neuropathic pain. This study is a randomized, placebo-controlled trial, where participants will be randomly assigned to receive either the capsaicin patch or a placebo, which is a hydrocolloid dressing. The trial is double-blind, ensuring that neither the participants nor the investigators know which treatment is being administered, thus minimizing bias. The trial is expected to commence on March 5, 2024, with an estimated completion date of November 1, 2025.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as age, gender, and the presence of persistent neuropathic pain. Following the initial application of the capsaicin or placebo patch, participants will be monitored for adverse events and vital signs, including cardiac frequency and arterial pressure. Follow-up visits will occur to assess the primary endpoint, which is the difference in the Neuropathic Pain Symptom Inventory (NPSI) score from baseline to four months post-treatment. Secondary endpoints include monitoring adverse events, physical examinations, and the intake of rescue medication.

The expected duration of participant involvement is approximately four months, with the possibility of early termination if adverse events occur or if the participant withdraws consent. The study aims to provide valuable insights into the treatment of neuropathic pain in a pediatric population, with the potential to improve pain management strategies for this demographic. Participants will be required to attend all scheduled visits and comply with study procedures to ensure the integrity of the trial data.

The clinical trial involves the use of **Qutenza**, a 179 mg **cutaneous patch** containing the active substance **capsaicin**. This pharmaceutical form is specifically designed for **cutaneous use**. The patch is applied directly to the skin, and the frequency of administration is determined by the study protocol, which may involve one or two applications over a four-month period. The primary objective is to assess the analgesic effectiveness of the capsaicin patch in treating chronic postsurgical or post-traumatic neuropathic pain in children aged 12 to 17 years. The product is manufactured by GRÜNENTHAL GMBH and is authorized for use in the European Union under the marketing authorization number EU/1/09/524/002.

In addition to the experimental treatment, the study utilizes **Comfeel Plus Transparent**, a hydrocolloid dressing classified as a medical device class IIB. This dressing is used as a comparator treatment and is applied cutaneously. The specific details regarding its application and role in the study are outlined in the study protocol and accompanying documentation. The hydrocolloid dressing serves as a non-experimental treatment to provide a standard-of-care comparison for the effectiveness of the capsaicin patch.

Furthermore, the trial includes the use of **Tramadol 100 mg/ml oral drops, solution** as an auxiliary treatment. Tramadol, an opioid analgesic, is administered orally in the form of drops. The dosing schedule and administration frequency are specified in the study protocol, ensuring that participants receive the appropriate dosage to manage pain symptoms effectively. The product is manufactured by MERCURY PHARMACEUTICALS LTD. and is authorized in the United Kingdom under the marketing authorization number PL 12762/0453. Participant compliance with the dosing regimen is monitored throughout the study to ensure adherence to the treatment protocol.

The efficacy of the capsaicin 8% cutaneous patch in treating chronic postsurgical or post-traumatic **neuropathic pain** in children aged 12 to 17 years will be assessed through a randomized placebo-controlled study. The primary endpoint for evaluating efficacy is the difference in the Neuropathic Pain Symptom Inventory (NPSI) score, measured between the first application of capsaicin or placebo (M0) and four months later (M4). The NPSI score is a validated tool used to quantify the severity of neuropathic pain symptoms, with higher scores indicating worse outcomes.

Secondary endpoints include monitoring adverse events during patch application and through follow-up phone calls, assessing vital signs such as cardiac frequency and arterial pressure, conducting physical examinations including dermal assessments, and recording the intake of rescue medication for pain. Additionally, the duration of patch application will be noted, and global scores and subscores of the NPSI questionnaire will be evaluated, with scores ranging from 0 to 100. The Functional Disability Inventory (FDI) questionnaire will also be used, with scores ranging from 0 to 60, where higher scores indicate worse outcomes. These assessments will provide a comprehensive evaluation of the patch's efficacy in managing neuropathic pain in the specified pediatric population.