Here is the design of a clinical trial:

Official Title: Phase II Randomized Controlled Study Aiming to Evaluate the Interest of Qutenza in Patients With Head and Neck Cancer in Remission and With Sequelae Neuropathic Pain.

Included conditions:
- Head and Neck Cancer

Study Armgroups:
- {'label': 'Experimental arm (A): capsaicin patch', 'type': 'EXPERIMENTAL', 'interventionNames': ['Drug: Capsaïcin patch (Qutenza®)']}
- {'label': 'Standard arm (B): amitriptyline', 'type': 'OTHER', 'interventionNames': ['Drug: Amitriptyline (Laroxyl®)']}

Interventions:
- {'type': 'DRUG', 'name': 'Capsaïcin patch (Qutenza®)', 'description': 'Treatment by application of capsaicin 8% (Qutenza®) patches 3 months apart (Month 1, Month 4 and Month 7).', 'armGroupLabels': ['Experimental arm (A): capsaicin patch']}
- {'type': 'DRUG', 'name': 'Amitriptyline (Laroxyl®)', 'description': 'Treatment by amitriptyline (oral solution 40mg/ml), for 9 months at the recommended dose of 25 mg to 75 mg daily.', 'armGroupLabels': ['Standard arm (B): amitriptyline']}

Primary Outcomes:
- {'measure': 'The rate of patients with a decrease in average pain over the last 24 hours by 2 points at 9 months compared to inclusion.', 'description': 'Pain will be assessed using a numerical scale from 0 to 10.', 'timeFrame': '9 months for each patient'}

Please estimate the sample size based on the assumption: 
one-sided chi-square test, alpha of 0.05%, 90% power, 5% lost to follow-up, randomization ratio 1:1
Sample size calculation
        Based on the literature, we expect 25% of patients to present with a pain decrease of at least two points [6]. To detect a 25% improvement (i.e., standard: 25%, experimental: 50%), using a one-sided chi-square test with an alpha of 0.05%, will require the enrollment of 125 patients, for 90% power. Assuming that 5% of patients will be lost to follow-up, we will need to randomize 130 patients (Randomization ratio1:1). According to the recommendations for comparative phase II trials, the target differences and type I error rates are relaxed.