The aims of this pilot study were to assess (1) the safety and tolerability of etanercept in dermatomyositis (DM), (2) the feasibility and safety of a forced prednisone taper, and (3) outcome measures, including those recommended by the International Myositis Assessment Clinical Study Group (IMACS).
We conducted a randomized, double-blind, placebo-controlled trial of etanercept (50 mg SQ weekly) for 52 weeks in DM subjects. Subjects were tapered off prednisone in a standardized schedule as tolerated over the initial 24 weeks of the study. Principal outcomes included adverse events, time from randomization to treatment failure (inability to wean off prednisone on schedule), and average prednisone dosage after Week 24.
Sixteen subjects were randomized, 11 to etanercept and 5 to placebo. There were no significant differences in adverse event rates between the treatment groups, although 5 etanercept-treated and 1 placebo-treated subjects developed worsening rash. All 5 subjects receiving placebo were treatment failures (median time to treatment failure 148 days). In contrast, 5/11 subjects in the etanercept arm were successfully weaned off prednisone; the median time to treatment failure in this group was 358 days (p = 0.0002). The median of the average prednisone dosage after Week 24 was 29.2 mg/day in the placebo group and 1.2 mg/day in the etanercept group (p = 0.02). IMACS and other outcome measures demonstrated excellent test-retest reliability (intraclass correlation coefficients 0.79 - 0.99). There was no significant treatment effect on functional outcome.
The observation of no major safety concerns and a steroid-sparing effect in our study suggest that further investigation of etanercept as a treatment for DM is warranted.