The efficacy of calcineurin inhibitors for the treatment of interstitial lung disease associated with polymyositis/dermatomyositis

Interstitial lung disease (ILD) in patients with polymyositis (PM) and dermatomyositis (DM) is often resistant to treatment and life threatening, being recognized as one of the severest complication in these autoimmune disorders. Patients with clinically amyopathic dermatomyositis (CADM) or those with anti-CADM140/MDA5 antibody are especially prone to develop rapidly progressive interstitial pneumonia. We retrospectively analyzed 46 patients with PM/DM admitted to our hospital and identified DM, rapidly progressive disease, honeycomb lung, CADM and extensive ILD as risk factors for recurrence or death. In the presence of two or more risk factors, the sensitivity and specificity for the prediction of death or relapse were 81.3% and 76.7%, respectively. Calcineurin inhibitors have been widely used as induction and maintenance therapy for PM/DM-associated ILD. Recently we reported the benefit of tacrolimus on the disease-free survival and event-free survival of the patients with PM/DM-associated ILD. Among those patients treated with tacrolimus, poor prognostic factors for death, recurrence or severe adverse event were identified as acute progression of the disease, honeycomb lung, forced vital capacity (FVC) less than 80% and having DM. The potential effectiveness of an intensive therapy protocol with triple therapy that comprises high-dose corticosteroids, calcineurin inhibitors and cyclophosphamide has been reported.