The efficacy of tacrolimus in patients with refractory dermatomyositis/polymyositis: a systematic review

The purpose of this study is to examine the efficacy and safety of tacrolimus (FK506) in the management of polymyositis (PM)/dermatomyositis (DM). The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, and China National Knowledge Infrastructure (CNKI) were searched to find articles published between May 1980 and April 2015 concerning tacrolimus therapy in PM/DM. The initial search yielded 107 articles. In the end, eight studies met our inclusion criteria and involved a total of 134 patients who received tacrolimus therapy for DM/PM. All studies were non-randomized. Oral tacrolimus of 0.075 mg/kg/day or 1.0-3.5 mg/d was administered twice daily or once daily together with glucocorticoids (GCs). According to comprehensive analysis of the studies, 93.3 % (42/45) and 64.7 % (11/17) of patients showed improvement in muscle strength and physical function status. The creatine kinase (CK) levels of 100 % (68/68) of patients decreased. The average dosage of GCs was reduced from 33.8 to 11.5 mg/day in PM/DM patients after the addition of tacrolimus. In the subject population, 65 patients had interstitial lung disease (ILD). After treatment, the forced vital capacity (FVC) and diffusing capacity for carbon monoxide (DLCO) improved or stabilized in 89.3 % (25/28) and 81.3 % (13/16) of patients, respectively. The commonly adverse events were nephrotoxicity, hypomagnesemia, tremors, and hypertension, but they were slight among these patients. Current evidence appears to support the use of tacrolimus in refractory PM/DM and PM/DM-ILD patients. Tacrolimus seems to be a safe drug that improves both muscle strength and lung function, and it is well tolerated by patients. However, this conclusion should be confirmed by large-sample, randomized controlled studies.