Clinical characteristics and management of immune checkpoint inhibitor-related pneumonitis: A single-institution retrospective study

Introduction The increasing application of immune checkpoint inhibitors (ICIs) will cause more checkpoint inhibitor-related pneumonitis (CIP), which is a common cause of ICI-related death. The clinical management of CIP needs further optimization. Methods Patients who were managed at Peking Union Medical College Hospital (PUMCH) between February 2017 and December 2019 with a diagnosis of CIP were retrospectively analyzed. Clinical data including clinical manifestations, radiologic data, laboratory and bronchoscopy results, treatments, and outcomes were collected and analyzed. The Mann-Whitney test was used to compare patients with and without co-infections. Results In total, 48 CIP cases in 42 patients were analyzed. The median time from the first dose of ICI to the onset of CIP was 1.9 months (range: 0.1-13.7). Grade 3-4 (G3-4) accounted for 30 cases (71.4%). The most common symptoms were cough (88.1%) and dyspnea (78.6%). The median starting dose of equivalent prednisone (EP) was 55 mg (range: 30-200) for all patients. The median total duration of glucocorticosteroids (GCS) treatment was 42.5 days (range: 15-89). Three patients (7.14%) died because of infection. A higher starting dose and longer duration of GCS (>= 30 mg/day; p = 0.001) were associated with opportunistic infection. Chest computed tomography (CT) showed diverse and asymmetrical lesions. Twelve patients were re-challenged, and six patients developed recurrent CIP. Conclusions The clinical and imaging manifestations of CIP are various, and differential diagnosis of exclusion is essential. GCS at 1-2 mg/kg is feasible to treat CIP, but the duration of GCS >= 30 mg/day should be used with caution, given the high risk of acquired infections. Re-challenges of ICI are feasible, but the recurrence of CIP needs to be closely monitored.