The goal of this multicenter, randomized, double-blind, placebo-controlled phase 2 clinical trial is to evaluate the efficacy and safety of proximod in active rheumatoid arthritis patients with inadequate response or intolerance to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs). The main questions it aims to answer are:
Evaluate the efficacy of different doses of proximod in active RA patients who have inadequate response or intolerance to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs), and provide a basis for dose selection in the confirmatory phase III clinical study.
Explore the changes of S1P and SPHK before and after treatment of proximod. Participants will take proximod 5mg/10mg daily or placebo for three months and will be followed up for 1 month.