Intravenous pulse cyclophosphamide in the treatment of interstitial lung disease due to collagen vascular diseases

Objective. Substantial toxicity limits the use of daily oral cyclophosphamide (CYC) for the treatment of interstitial lung disease (ILD) due to collagen vascular diseases. We examined whether intravenous (IV) pulse CYC can be substituted for daily oral therapy. Methods. Six patients with rapidly progressive ILD due to polymyositis, systemic sclerosis, systemic lupus erythematosus, or primary Sjogren's syndrome received 6-9 cycles of IV pulse CYC (0.5 gm/m² of body surface area), together with an initial course of 50 mg of prednisolone, which was tapered to a maintenance dosage of 5-7.5 mg/day, and their response was measured clinically, by high-resolution computed tomography (HRCT) and by assessment of the bronchoalveolar lavage (BAL) cell profile. Results. All patients showed significant improvement in exercise tolerance and lung function. Elevated BAL neutrophils dropped substantially, whereas the response of BAL lymphocytes was inconsistent. Low- attenuation opacities in the HRCT regressed in 4 patients and remained unchanged in 2, but reticular infiltrates remained largely unaffected. Remission was maintained with hydroxychloroquine, azathioprine, or cyclosporin A. Conclusion. IV pulse CYC proved to be an effective and well- tolerated treatment in these patients. Since it appears to target mainly the inflammatory component of the disease, it should be reserved for progressive ILD featuring indices of high inflammatory activity.