Efficacy and safety of mirogabalin in patients with fibromyalgia: protocol for a multicentre, Prospective, Randomised, Open-label, Blinded Endpoint (PROBE) study.

introductionFibromyalgia (FM) is a prevalent chronic pain condition that significantly impairs quality of life. The current treatments for FM still have some disadvantages and limitations. Pregabalin, a standard pharmacological treatment, provides relief for some patients but is associated with dose-dependent adverse events (AEs) and incomplete efficacy, highlighting a significant unmet clinical need. Mirogabalin, as a novel α2δ ligand similar to pregabalin but with distinct binding properties, has shown a favourable safety profile and potential analgesic effects in preclinical studies and trials for other neuropathic pain conditions. However, data on its efficacy in FM are limited and no studies have directly compared mirogabalin with pregabalin in an Asian FM population. METHODS AND ANALYSIS: This is a prospective, multicentre, randomised, open-label, blinded endpoint trial to compare the efficacy and safety of mirogabalin versus pregabalin for the management of pain and other core symptoms in adult patients with FM. This study will be conducted at the Department of Pain Management, Beijing Tiantan Hospital, the First Affiliated Hospital of Nanchang University, Chongqing University Three Gorges Hospital, the First Affiliated Hospital of Army Medical University and the Affiliated Hospital of Yanbian University. Patients aged over 18 years, diagnosed with FM according to the 2016 Revisions to the 2010/2011 FM diagnostic criteria, will be enrolled. 674 qualified patients experiencing moderate-to-severe FM will be randomly assigned to either the pregabalin group or the mirogabalin group in a 1:1 ratio. Treatment will involve individualised dose titration based on treatment response and tolerability. All participants will be followed for a duration of 12 weeks. The primary outcome will be the proportion of patients achieving a pain reduction of at least 50% at 12 weeks. Secondary endpoints will include the average pain intensity, the worst pain intensity, the Revised FM Impact Questionnaire, the Brief Pain Inventory severity and interference subscales, the Short-Form 36 Health Survey, the Medical Outcomes Study Sleep Scale, the Beck Depression Inventory-II, AEs throughout the study. An open-label administration is selected to reflect real-world clinical practice and to allow individualised dose titration according to tolerability and response, while blinded endpoint assessment is implemented to minimise evaluation bias and preserve methodological rigour. ETHICS AND DISSEMINATION: This study was approved by the Institutional Review Board of Beijing Tiantan Hospital, Capital Medical University (KY2025-217-03), the First Affiliated Hospital of Nanchang University (IIT (2026) Clinical Ethics Review no. 676), Chongqing University Three Gorges Hospital (2026 Scientific Ethics Review no. 41), the Affiliated Hospital of Yanbian University (Yan Medical Ethics no. 20260275) and the First Affiliated Hospital of Army Medical University (AIIT2026081KX). All participants will provide written informed consent prior to enrolment. This study will be conducted in accordance with the Declaration of Helsinki. Findings from this study will be disseminated through peer-reviewed journals and at scientific conferences. TRIAL REGISTRATION NUMBER: NCT07157852.