Successful rescue treatment of refractory anti-MDA5 autoantibody positive dermatomyositis with rapidly progressive interstitial lung disease using daratumumab

Anti-melanoma differentiation-associated 5 gene autoantibody (anti-MDA5 Ab) positive dermatomyositis (DM) with rapidly progressive interstitial lung disease (RP-ILD) is a severe and difficult-to-treat form of autoimmune myositis with unfavourable 6-month survival rates. We report a case of refractory anti-MDA5 DM RP-ILD that improved after daratumumab, a human monoclonal antibody targeting CD38-positive plasma cells.