The efficacy of tacrolimus in patients with interstitial lung diseases complicated with polymyositis or dermatomyositis.

Interstitial lung diseases (ILDs) complicated with PM or DM are frequently aggressive and refractory to treatment. Recently some reports have suggested the potential benefit of tacrolimus for severe ILD complicated with PM/DM. However, little evidence has yet shown the efficacy of tacrolimus in these settings. The aim of this study was to evaluate the efficacy of tacrolimus as a treatment for PM-/DM-related ILD. This retrospective study comprised 49 previously untreated patients diagnosed as PM-/DM-related ILD admitted to Hokkaido University Hospital from January 2000 to July 2013. These patients were treated with tacrolimus plus conventional therapy or only with conventional therapy (prednisolone, i.v. CYC and/or ciclosporin). The primary endpoint was defined as the time to relapse or death of respiratory cause or a serious adverse event. The secondary endpoint was defined as the time from the initiation of immunosuppressive treatment to relapse or death of respiratory cause. Endpoints were compared by adjusted Cox regression model by using inverse probability of treatment weighting in order to reduce the impact of these selection biases and potential confounding factors. After adjustment, the tacrolimus group (n = 25) had significantly longer event-free survival as compared with the conventional therapy group (n = 24). The weighted hazard ratio (HR) was 0.32 (95% CI 0.14, 0.75, P = 0.008). In addition, the tacrolimus group had significantly longer disease-free survival as compared with the conventional therapy group. The weighted HR was 0.25 (95% CI 0.10, 0.66, P = 0.005). The addition of tacrolimus to conventional therapy significantly improved the prognosis of patients with PM-/DM-related ILD.