In recent years an immune-mediated inflammatory process has been implicated in the genesis of the pulmonary damage seen in patients with cystic fibrosis.1,2 A 4-year double-blind, placebo-controlled trial of alternate-day prednisone (2 mg/kg) was conducted in 45 cystic fibrosis patients with mild-to-moderate pulmonary disease to assess the effect of this drug on the pulmonary inflammatory process.3 The patients in the prednisone group showed better growth and pulmonary function and less morbidity compared with those in the placebo group. No complications were reported among the prednisone-treated patients. To extend these observations, the United States Cystic Fibrosis Foundation sponsored a multicenter double-blind, placebo-controlled trial of alternate-day prednisone. Since March 1986, 283 patients with cystic fibrosis, followed up at 15 centers in the United States and Canada, have been enrolled in this trial. Patients 5 through 14 years of age with mild-to-moderate pulmonary disease were randomly assigned to receive prednisone 2 mg/kg (high-dose) every other day, prednisone 1 mg/kg (low-dose) every other day, or placebo. On entry into the study, patients in the three groups were closely matched by a variety of clinical and laboratory parameters (Table 1).
Patients are closely monitored at 3-month intervals for both efficacy and side effects. An interim analysis is carried out every 6 months and the results are reviewed by an unblinded study ombudsman. Initially, 95 patients were randomly assigned to the high-dose group, 94 to the low-dose group, and 94 to the placebo group. At the time of the most recent interim analysis, mean duration in the study was 33.9 months for the high-dose group, 35.3 months for the low-dose group, and 36.8 months for the placebo group.