Cepharanthine and Oral Lichen Planus Efficacy (COLE) study: protocol for a multicentre randomised controlled study assessing the efficacy and safety of cepharanthine with topical corticosteroids in oral lichen planus

INTRODUCTION: Oral lichen planus (OLP) is a chronic, inflammatory oral condition leading to a range of symptoms from mild discomfort to severe pain, affecting patients’ quality of life. Standard therapy involves the use of topical corticosteroids, although some patients respond insufficiently or develop resistance to therapy. We aim to explore if adding cepharanthine, an herbal extract from Stephania cepharantha Hayata, can enhance the efficacy of corticosteroid therapy in symptomatic OLP. METHODS AND ANALYSIS: This open-label, parallel-group, multi-centre, randomised controlled study will be conducted at three Japanese hospitals. It will compare safety and efficacy of integrated oral cepharanthine and corticosteroid therapy versus standard corticosteroid therapy. 50 symptomatic OLP patients will be randomised 1:1 to receive cepharanthine (30 mg/day) plus topical dexamethasone, or topical dexamethasone alone for 8 weeks. The primary outcome will be changed in pain intensity while drinking room-temperature water, measured on a visual analogue scale. The primary outcome is the change in pain intensity from baseline when drinking room-temperature water, evaluated using a visual analogue scale. Secondary outcomes are changes in the longest diameter of the target lesion from baseline to weeks 4 and 8, improvement and deterioration rates according to appearance and severity criteria at weeks 4 and 8, change in pain intensity when drinking room-temperature water from baseline to week 4, changes in pain intensity at rest from baseline to weeks 4 and 8, and the rates of adverse events. ETHICS AND DISSEMINATION: This protocol was approved by the Certified Review Board of Nara Medical University (CRB5200002). Participants will provide informed consent. Results will be disseminated in peer-reviewed journals and conferences. TRIAL REGISTRATION NUMBER: Japan Registry of Clinical Trials (jRCTs051220130).