Outcomes of Patients With Interstitial Lung Disease Receiving Programmed Cell Death 1 Inhibitors: A Retrospective Case Series.

Background: Immune checkpoint inhibitors (ICIs), such as programmed cell death 1 (PD-1) inhibitors, are used to treat multiple cancers. Limited data exist as to the use of ICIs in patients with coexistent interstitial lung disease (ILD). We conducted a retrospective case series to assess clinical and radiologic outcomes of patients with ILD treated with PD-1 inhibitors.

Methods: Eligible patients were 18 years of age or older, treated with pembrolizumab or nivolumab for oncologic indications, and had evidence of ILD on chest computed tomography scan not attributable to radiotherapy before initiation of ICI therapy. Outcomes of interest included mortality, hospitalizations for respiratory-related causes, development of pneumonitis, and radiologic change in ILD over a 1-year follow-up period.

Results: We included 41 patients in the analysis. At 1 year, 17 patients (41.5%) were alive, 23 had died (56.1%), and 1 (2.4%) was lost to follow-up. Of 23 deaths, 16 (69.6%) were due to cancer, 4 (17.4%) to causes excluding cancer and ILD, and 3 (13.0%) to hypoxemic respiratory failure from ILD- or ICI-induced pneumonitis. Three patients (7.3%) required hospitalization owing to ILD, including drug-induced pneumonitis, and 3 (7.3%) developed pneumonitis attributable to anti-PD-1 therapy. On follow-up computed tomography scans, 32 patients (78.0%) had stable or improved ILD and 9 (22.0%) had progression.

Conclusion: Patients with ILD receiving PD-1 inhibitors more frequently died of cancer-related causes than from ILD. Further research is needed to determine the safety of ICIs in patients with ILD and if ILD subtype may help to refine ICI-associated risks.