Successful multi‐target therapy including rituximab and mycophenolate mofetil in anti‐melanoma differentiation‐associated gene 5 antibody‐positive rapidly progressive interstitial lung disease with clinically amyopathic dermatomyositis

Successful multi-target therapy including rituximab and mycophenolate mofetil in anti-melanoma differentiation-associated gene 5 antibody-positive rapidly progressive interstitial lung disease with clinically amyopathic dermatomyositis Dear Editor, Interstitial lung disease (ILD) in dermatomyositis (DM) is a serious complication that affects patient prognosis.ILD associated with clinically amyopathic DM (CADM) is more refractory and rapidly progressive than classical DM.Sato et al. identified anti-melanoma differentiation-associated gene 5 (MDA5) antibody and reported that about half of the patients with CADM positive for this antibody developed rapidly progressive ILD (RP-ILD).1 The cumulative 6month survival rate is reported to be approximately 50% for RP-ILD with anti-MDA5 antibody.2 In classic DM patients, ILD can progress rapidly when they are anti-MDA5 antibody positive.Here, we present a case of worsening RP-ILD despite treatment with high-dose prednisolone (PSL) combined with cyclosporine (CSA) and intravenous cyclophosphamide (IVCY) in a patient with anti-MDA5 antibody-positive CADM.The addition of polymyxin-B direct hemoperfusion (PMX-DHP), mycophenolate mofetil (MMF), intravenous immunoglobulin (IVIG), and rituximab (RTX) led to remission of the disease.