Clinical and MRI response to dose reduction of an etanercept-biosimilar for hip arthritis in patients with ankylosing spondylitis: an observational, retrospective cohort study

Objectives Hip arthritis plays a critical role in the prognosis of ankylosing spondylitis (AS). Dose reduction of tumor necrosis factor inhibitors preserves general improvement of AS, so this study attempted to examine the equivalence between Yisaipu® tapering and conventional therapy for hip arthritis in AS patients, using clinical parameters and magnetic resonance image (MRI).