Anti-IL-5 Agents for the Treatment of Idiopathic Chronic Eosinophilic Pneumonia: A Case Series

PURPOSE: Idiopathic chronic eosinophilic pneumonia (ICEP) is a rare, chronic respiratory disease. Corticosteroid therapy is effective for ICEP, but relapse is frequent after its tapering, which leads to chronic use and corticosteroid-related adverse effects. Currently, biological agents targeting interleukin 5 (IL-5) are considered alternatives for treating ICEP patients with frequent relapse, but the detailed effects are not fully understood. PATIENTS AND METHODS: The clinical characteristics of 30 patients with ICEP, especially 12 patients with ICEP who experienced relapse after corticosteroid dose tapering, were evaluated retrospectively. In addition, 4 ICEP patients with frequent relapse treated by IL-5-targeted biological agents were reviewed. RESULTS: Of the 30 patients diagnosed with ICEP, 12 patients (40.0%) recurred after corticosteroid dose tapering, and 9 (30.0%) were treated with maintenance doses of corticosteroid. Of ICEP patients who experienced recurrence, 6 (50.0%) had frequent relapses (2 or more times). All 4 patients treated with anti-IL-5 agents had their corticosteroid dose reduced without any relapses; in 3 patients, corticosteroids were withdrawn. CONCLUSION: Anti-IL-5 agents might be alternatives for treating ICEP patients with frequent relapses.