Objectives: To assess the efficacy and safety of intravenous cyclophosphamide (CYP) used in severe and refractory juvenile dermatomyositis (JDM).
Methods: Retrospective case note review of the outcome of 12 patients.
Results: Assessment at 6 months of therapy in 10 of the 12 patients showed a significant improvement in muscle function as assessed by the Childhood Myositis Assessment Scale (CMAS) (P = 0.012), muscle strength (P = 0.008), global extramuscular disease score (P = 0.008), skin disease severity (P = 0.015) and lactate dehydrogenase (P = 0.028). There were reductions in creatine kinase, alanine aminotransferase, prednisolone dose and ESR, but these did not reach statistical significance. Clinical improvement was maintained after CYP until the most recent follow-up (between 6 months and 7 yr) and no severe side-effects were seen. Reversible complications included lymphopenia, herpes zoster infections and alopecia. The median cumulative dose was 4.6 g/m(2) (range 3-9 g/m(2)). The available evidence suggests that, at the doses required, risks of malignancy, infertility and gonadal failure are low. Two patients with severe treatment-resistant disease died after one dose of CYP, both of whom were ventilated prior to commencement of CYP and were thought to have died as a result of their severe disease process, and too early for clinical benefit to be obtained from the drug.
Conclusions: In this cohort of children with severe and refractory JDM, CYP appeared to have provided major clinical benefit with no evidence of serious toxicity in the short term.