Chemotherapy induced peripheral neuropathy (CIPN) is a frequent and disabling complication of systemic chemotherapy, particularly with oxaliplatin or taxanes. The incidence of CIPN is variable but approximately 30-40% of patients treated with neurotoxic chemotherapy agents develop CIPN after long-term use of taxanes or oxaliplatin.

This CIPN is essentially a sensory peripheral neuropathy with pain manifested by unpleasant symptoms such as numbness, tingling, and less frequently shooting/burning pain. These symptoms spread proximally to affect both lower and upper extremities in a characteristic "stocking and glove" distribution.

Many symptoms of CIPN may resolve completely for some patients. However, CIPN is only partly reversible for most. In the worst instances, it does not appear to be reversible at all and can even increase over time.

CIPN is difficult to manage. Only duloxetine is recommended, based on the positive result of a randomized phase III double-blind placebo-controlled crossover trial. The use of duloxetine resulted in a greater reduction in pain and was effective in decreasing numbness and tingling in the feet. But, systemic antidepressants are often associated with toxicities and patients often refuse or abandon the treatment.

Capsaicin inhibits neural transmission in sensory axons and has been proven as effective on the intensity of pain for post-herpetic neuralgia and human immunodeficiency virus-associated neuropathy. Efficacy appears at one month and persists for at least 2 months.

Only a few studies focused on the efficacy of capsaicin 179 mg patch on the intensity of CIPN-induced pain. These non-randomized studies show that more than 50% of patients have a reduction in pain intensity of more than 30%.

Until now, no clinical trial has compared the efficacy of the capsaicin 179 mg patch with duloxetine.

Accordingly, this open-label phase 3, randomized, multicenter trial, will compare efficacy and safety of capsaicin patch with oral duloxetine on painful CIPN persisting more than 3 months after the end of the responsible chemotherapy.

Inclusion Criteria:

• Patient with CIPN manifested by painful symptoms such as numbness and / or tingling and / or burning pain in fingers / hands and toes / feet with a typical distribution in "gloves and socks" beginning after neurotoxic chemotherapy
• Painful CIPN as expressed by the BPI-SF (average pain) as ≥ 4/10
• CIPN persisting at least 1 month after completion of chemotherapy with taxanes and/or platinum salts and sensory CIPN grade ≥ 2 according to the NCI Common Toxicity Criteria for Adverse Events (CTCAE v.5.0) grading scale
• Stable doses in the 4 weeks before screening, of concomitant neuropathic pain medication (antiepileptic drugs)
• Healthy and non-irritated skin on the areas to be treated
• Absence of neurotoxic chemotherapy planned during the next 6 months after inclusion
• Patient affiliated to a social security scheme
• > 18 years old
• Signed written informed consent form

Exclusion Criteria:

• Presence of known carcinomatous meningitis
• Pre-existing known peripheral neuropathy of another aetiology (alcohol, diabetes, …)
• Hypersensitivity to Capsaicin or contra-indications to duloxetine (e.g imatinib, tamoxifen)
• Patient already treated for this neuropathy with Capsaicin patches
• Patient treated by antidepressant drugs at time of inclusion
• Uncontrolled hypertension (systolic blood pressure ≥ 180 mmHg or diastolic blood pressure ≥ 90 mmHg) or recent history (<3 months) of cardiovascular events (stroke, heart attack, pulmonary embolism)
• Patients with known severe renal or hepatic failure
• Breastfeeding or pregnant women
• Persons deprived of liberty or guardianship (including curatorship)
• Patient unable to undergo regular medical follow-up for geographical, social or psychological.