Landscape of Immune-Related Pneumonitis in Cancer Patients with Asthma Being Treated with Immune Checkpoint Blockade.

INTRODUCTION: Predicting the factors that increase the risk of immune-related pneumonitis, a potentially life-threatening complication of treatment with immune checkpoint inhibitors for cancer, is a clinical challenge. Baseline clinical factors such as asthma may portend the development of pneumonitis due to pre-existing airway inflammation prior to immunotherapy. OBJECTIVE: The purpose of the study was to investigate whether a prior diagnosis of asthma is associated with an increased risk of immune-related pneumonitis in patients undergoing cancer immunotherapy. METHODS: Patients at the Moores Cancer Center at UC San Diego Health undergoing immunotherapy were identified on an IRB-approved protocol. Clinical charts were reviewed for asthma documented in the medical records and CT scans were reviewed during and after treatment. Pneumonitis was defined as the onset of new pulmonary symptoms with characteristic imaging findings during or after a patient's first course of immunotherapy that could not be readily explained as infection or a progression of malignancy. It was graded according to the Common Terminology Criteria for Adverse Events. RESULTS: A total of 187 patients were included. A diagnosis of asthma was found in the records of 26 cases (13.9%). Pneumonitis was found in 10 cases (5.35%); 50% were grade 2 and 50% were grade 3-4. Two of the grade 3-4 cases (40%) occurred in patients with non-small-cell lung cancer. Three patients with asthma developed pneumonitis (11.5% of patients with asthma), all grade 3-4. Only 28.6% of the non-asthma-pneumonitis cases were grade 3-4. All (100%) of the asthma-pneumonitis patients were former smokers, while 71.4% of the non-asthma-pneumonitis patients were former smokers. CONCLUSION: A history of asthma may be associated with a higher grade of pneumonitis if it develops, and a history of smoking may augment this relationship.