Pilot study of etanercept in patients with refractory juvenile dermatomyositis

To evaluate the efficacy of etanercept in patients with juvenile dermatomyositis (DM) refractory to standard treatment.

Nine patients with juvenile DM prospectively received etanercept 0.4 mg/kg subcutaneous twice weekly concurrently with baseline medications for 12 weeks. Patients were reevaluated 12 weeks (week 24) after stopping etanercept. Outcome measures included a validated Disease Activity Score (DAS), serum muscle enzymes, Childhood Myositis Assessment Scale (CMAS), and nailfold capillaroscopy (NFC).

Six patients completed all visits; 2 patients completed through week 12 and 1 patient stopped after the fifth etanercept dose due to marked worsening of a rash. At week 12, 7 patients had a mild decrease in DAS and 1 patient noted worsening of the DAS. At week 24, 1 patient remained stable, 2 patients had worsening of the DAS, and 3 patients had improvement of the DAS (1 patient with inactive disease), including the patient who worsened while receiving etanercept. This patient and the patient who stopped (worsening rash) both had the tumor necrosis factor α (TNFα) 308A allele. There was a trend of worsening NFC at week 12, while at week 24 improvement of NFC was noted. There was no appreciable change in serum muscle enzymes or CMAS throughout the study.

In this trial of patients with refractory juvenile DM, etanercept did not demonstrate appreciable improvement and some patients noted worsening of disease. Caution should be taken when recommending TNF receptor inhibitors to patients with active symptoms of juvenile DM, and close followup is warranted. Further investigation of the interaction of the TNFα-308A polymorphism and type I interferon is needed to define the mechanism of TNF blockade in juvenile DM.