Treatment with low‐dose nintedanib and tacrolimus in patients with progressive fibrosing interstitial lung diseases with anti‐ARS antibody‐positive dermatomyositis

Nintedanib has been demonstrated to inhibit the rate of forced vital capacity decline in patients with progressive fibrosing interstitial lung diseases (PF‐ILD) at a dose of 200 or 300 mg/day in the INBUILD trial. Although concomitant use of nintedanib with P‐glycoprotein inhibitors reportedly increases the plasma concentrations of the former, tacrolimus, a P‐glycoprotein inhibitor, is often used to treat connective tissue diseases‐related interstitial lung diseases. The optimal dose of nintedanib in combination with tacrolimus for the treatment of PF‐ILD with connective tissue disease is unknown. We herein present two patients with PF‐ILD with anti‐aminoacyl‐tRNA synthetase antibody‐positive dermatomyositis who were successfully treated with low‐dose nintedanib (