Corticosteroid-sparing effect of tacrolimus in the initial treatment of dermatomyositis and polymyositis.

OBJECTIVE

In the treatment of polymyositis (PM) and dermatomyositis (DM), muscle inflammation and underlying autoimmunity need to be suppressed promptly; however, catabolic effects of corticosteroids such as myopathy can be detrimental in PM/DM. In this study, we aimed to assess the corticosteroid-sparing effect of tacrolimus in the initial treatment of PM/DM.

METHODS

We retrospectively identified 19 PM/DM patients who received initial treatment with prednisolone at an initial dose of 1 mg/kg/day (Conventional Monotherapy, our standard therapy before 2008) and 23 patients with tacrolimus plus prednisolone at an initial dose 0.8 mg/kg/day (Tacrolimus Combination, our standard therapy after 2008). Data until 36 months after commencing treatment were collected.

RESULTS

There were no statistically significant differences in baseline characteristics between two groups. Median daily dose of prednisolone in the Tacrolimus Combination Group was significantly lower than that in the Conventional Monotherapy Group during the study period, whereas the proportion of patients who required additional immunosuppressive medications for remission induction was comparable. Remission was achieved in all patients, except one who died of refractory interstitial lung disease after receiving Conventional Monotherapy. The time required for creatine kinase normalization and relapse rate was comparable between two groups. The period of hospitalization for initial treatment was significantly shorter and survival without serious infection or relapse tended to be longer in the Tacrolimus Combination than the Conventional Monotherapy.

CONCLUSION

This study provides real-life data which demonstrate that tacrolimus has a corticosteroid-sparing effect and reduces the length of hospitalization period for the initial treatment of PM/DM.