Objective:The aim of this study was to evaluate the efficacy of pirfenidone for patients with rapidly progressive ILD(RPILD)related to clinically amyopathic dermatomyositis(CADM).Methods:Thirty patients diagnosed CADM-RPILD with disease duration <6 months,at Renji Hospital South Campus from June 2014 to November 2015,were prospectively enrolled and treated with pirfenidone at a target dose of 1800mg/d on top of conventional treatment,such as corticosteroid and other immunosuppressants.Matched patients without prifenidone(n=27)between October 2012 and September 2015 were retrospectively selected as controls.Intent-to-treat analysis was applied with the12-month survival changes as the endpoint.