Presentation (CTI)

OBJECTIVES: Immune checkpoint inhibitors (ICIs) are being the cornerstone for non-small cell lung cancer (NSCLC) treatment but are associated with immune-related adverse events, including pneumonitis. Patients with chronic obstructive pulmonary disease (COPD) are vulnerable to pulmonary toxicity; however, real-world data describing pneumonitis incidence following ICI initiation stratified by COPD status remain limited. This study estimates the incidence of pneumonitis after ICI initiation among NSCLC patients and to describe differences by pre-existing COPD status.
METHODS: We conducted a retrospective cohort study using claims data from Merative MarketScan database. Adult patients with NSCLC who initiated ICIs in 2022 were identified using diagnosis and procedure codes using index date defined as the first observed ICI claim. Pre-existing COPD was identified during a 12-month baseline period prior to ICI initiation using inpatient or outpatient diagnosis codes. Patients with evidence of pneumonitis during baseline were excluded. The primary outcome was incidence of pneumonitis identified from inpatient or outpatient claims within 180 days following ICI initiation. Incidence proportions were calculated overall and stratified by COPD status. Exploratory multivariable logistic regression was performed to examine baseline factors associated with pneumonitis.
RESULTS: Among 1,248 NSCLC patients initiating ICIs with a mean age of 58.5 years (SD 6.4); 51.8% were female and Pre-existing COPD was present in 203 patients (16.3%). The overall 180-day incidence of pneumonitis was 4.25% (53 events). Pneumonitis incidence was 4.93% among patients with COPD compared with 4.11% among patients without COPD.
CONCLUSIONS: In this real-world claims-based cohort, pneumonitis occurred in approximately 4% of NSCLC patients within six months of ICI initiation, with a slightly higher incidence observed among patients with pre-existing COPD. These findings provide population-level incidence estimates that inform pulmonary risk stratification and clinical monitoring in NSCLC patients receiving immunotherapy.