Mirogabalin treatment of postoperative neuropathic pain after thoracic surgery: study protocol for a multicenter, randomized, open-label, parallel-group, interventional trial

BACKGROUND: Intercostal nerve damage due to thoracotomy or thoracoscopic manipulation is a major contributor to chronic postsurgical pain after pulmonary resection. Chronic postsurgical pain may last for months or years and can negatively impair physical functioning and daily activities. Global consensus on severe postoperative pain management is lacking, and chronic pain incidence after thoracic surgery remains high. Many patients report neuropathic pain, which can be difficult to treat with currently available therapies. The efficacy and safety of mirogabalin have been demonstrated for other types of neuropathic pain; thus, this study was planned to investigate the efficacy and safety of mirogabalin to treat neuropathic pain after thoracic surgery. METHODS: In this multicenter, randomized, open-label, parallel-group, interventional study, patients who are diagnosed with neuropathic pain following removal of a chest drain after lung resection will receive conventional therapy (non-steroidal anti-inflammatory drugs and/or acetaminophen) with or without the addition of a clinical dose of mirogabalin for 8 weeks. For patient stratification, a visual analog scale pain intensity score at baseline of <60 vs. ≥60 mm will be used. Treatment efficacy and safety with and without the addition of mirogabalin will be assessed using a questionnaire evaluating postoperative changes in pain severity and activity. The primary study endpoint is the change in pain intensity from baseline to Week 8, measured by the visual analog scale. Additionally, the presence of chronic pain at 12 weeks after enrollment in each treatment group will be recorded. DISCUSSION: This protocol has been reviewed and approved by the Clinical Research Review Board of Nagasaki University. Study data will be published in the Japan Registry of Clinical Trials database and peer-reviewed journals. Mirogabalin is already approved for the treatment of other types of neuropathic pain. It is anticipated that this study will provide data to elucidate the impact of mirogabalin treatment, in combination with conventional therapy, to benefit patients with neuropathic pain following thoracic surgery. TRIAL REGISTRATION: Japan Registry of Clinical Trials Identifier: jRCTs071200053.