Efficacy and limitations of pulse cyclophosphamide therapy in polymyositis and dermatomyositis

To assess the therapeutic response of intravenous (IV) pulse cyclophosphamide therapy in polymyositis and dermatomyositis.

Data of 9 patients (M:F = 2:7) who received IV pulse cyclophosphamide therapy were retrospectively analyzed.

The mean symptom duration was 11.33 ± 10.6 months (range, 2-34 months). The cohort comprised (1) primary idiopathic polymyositis (n = 1), (2) primary idiopathic dermatomyositis (n = 1), (3) childhood type associated with vasculitis (n = 1), and (4) associated with collagen vascular disease (n = 6). All patients improved and became clinically asymptomatic after a mean period of 12.33 ± 6.5 months (range, 4-24 months); 5 remained asymptomatic at the end of a median follow-up period of 22 months. All patients received concomitant steroid therapy, and in 6, steroids could be tapered after the initiation of IV pulse cyclophosphamide therapy.

In this cohort of polymyositis/dermatomyositis, treatment with IV pulse cyclophosphamide was associated with improvement; the therapeutic response was sustained in majority of the patients.