According to recent case reports and small series, adjunctive treatment with tacrolimus may be beneficial in patients with myositis-associated interstitial lung disease (MA-ILD) who are refractory to conventional therapies.

A retrospective cohort study, published in Annals of the Rheumatic Diseases, investigated a cohort of patients with MA-ILD to compare clinical characteristics of patients who responded to conventional treatment vs patients who did not. Patients were considered as not responding to conventional treatment if they presented with refractory myositis, defined by worsening muscle weakness or serum creatine kinase levels that do not normalize, or refractory ILD, defined by at least two of the following criteria: 10% decrease in total lung capacity, 10% decrease in functional vital capacity, 15% decrease in diffusing capacity of the lungs for carbon monoxide, or worsening of respiratory symptoms.

In patients who did not respond to conventional treatment and received adjunctive tacrolimus, the response to the agent was assessed by clinical improvements in myositis, ILD, and changes in glucocorticoid and disease-modifying antirheumatic drug (DMARD) doses.

A total of 54 patients with MA-ILD were included in the study. All of the participants received conventional treatment with prednisone and ≥1 DMARD. Of the patients studied, 31 of 54 (57%) responded to conventional treatment based on predefined variables of improvement in myositis and/or ILD. Patients with polymyositis (PM)-ILD were significantly more likely to respond to conventional therapy than patients with dermatomyositis (DM)-ILD (67% vs 35%, respectively; P =.013).

Overall, 23 patients did not respond to conventional therapy and received additional treatment with either cyclophosphamide (CYC) or tacrolimus. A total of 18 patients met  the study inclusion criteria and were included in the final analysis. Of the 18 tacrolimus-treated patients, 14 (78%) exhibited improvements in myositis, 17 (94%) showed improvements in ILD, and 13 (72%) demonstrated improvements in both. The mean dose of prednisone used by the participants decreased from baseline by 65% at 3 to 6 months (P =.02) and by 81% at 12 months (P <.001).

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Although patients with PM-ILD were more likely to respond to conventional therapy than patients with DM-ILD, clinical characteristics and serology did not otherwise predict participants’ response to therapy. A majority of patients with MA-ILD who were refractory to conventional therapy improved while being treated with tacrolimus, thus decreasing their dose of both glucocorticoids and other DMARDs.

According to the researchers, randomized prospective multicenter studies in patients with MA-ILD that analyze the efficacy and safety of tacrolimus earlier in the disease course may prove helpful.

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Reference

Sharma N, Putman MS, Vij R, Strek ME, Dua A. Myositis-associated interstitial lung disease: Predictors of failure of conventional treatment and response to tacrolimus in a US cohort [published online September 1, 2017]. J Rheumatol.  doi:10.3899/jrheum.161217