Wangbi granule as a combination therapy to achieve clinical deep remission in rheumatoid arthritis: protocol for a multicenter, triple-blind, randomised, placebo-controlled trial.

INTRODUCTION: Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that may lead to bone erosion and disability. Although there are many biological therapies in RA treatment nowadays, such as etanercept and tofacitinib, there are still a considerable number of patients who cannot achieve clinical deep remission, which makes patients feel pain and stiffness of joints. As a traditional Chinese medicine preparation, Wangbi granule showed a synergistic role with methotrexate in the treatment of RA patients with "kidney deficiency and dampness" or "stasis blocking channels". Therefore, it is a promising therapeutic strategy for the clinical deep remission of RA. In this study, Wangbi granule will be used as the test drug. The investigators conduct this study to evaluate the efficacy and safety of Wangbi granule in the treatment of patients who have not achieved deep remission despite the use of methotrexate and tofacitinib.

METHODS AND ANALYSIS: Two parallel randomized, triple-blind, placebo-controlled trials will be conducted. In six study centers, 340 eligible RA patients will be recruited and randomly allocated to either the intervention group or the control group (in a 1:1 ratio). They will receive Wangbi granule or Wangbi placebo 12.0 g each time, three times a day for 12 weeks. The primary outcome is the disease activity score derivative for 28 joints (DAS28). Secondary outcomes are patient-reported outcomes, American College of Rheumatology 50% response criteria (ACR50), fatigue scale-14 (FS-14), visual analogue scale for pain (VAS), health assessment questionnaire disability index (HAQ-DI) and biomarkers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR).

EXPECTED OUTCOMES: The success of this study will provide strong evidence to confirm the efficacy and safety of Wangbi granule in the treatment of RA. Trial registration The trial has been registered in the ClinicalTrials Registry (NCT05540938, Date: 09/15/2022, https://clinicaltrials.gov/ct2/show/NCT05540938 ).