Frequency of immune-related adverse events of immune-checkpoint inhibitors for non-small cell lung cancer in our single institution

Single use or combination of immune-checkpoint inhibitor (ICI) with cytotoxic chemotherapeutic agents is the standard treatment for non-small cell lung cancer (NSCLC). The combination therapy demonstrated superiority of outcome to cytotoxic chemotherapy with acceptable toxicities. However, there is no phase 3 study comparing combination therapy and single ICI. To investigate the frequency of immune-related adverse events (irAE) of ICI treatment for NSCLC in our institution. This is retrospective analysis checking medical record of all ICI treatment patients by August 2020. Total number of ICI treated patients were 358, any grade/grade 3 or higher of irAE occurred in 135 (37.7%)/56 (15.6%), respectively. Combination therapy to 80 patients, any/grade 3 or higher irAE in 36 (45%)/19 (23.8%). Chemoradiation followed by ICI maintenance therapy to 31 patients, any/grade 3 or higher irAE in 10 (32.3%)/1 (3.2%). Single use of ICI to 247 patients, any/grade 3 or higher irAE in 89 (36%)/36 (14.6%). The irAE occurred more frequently in the combination therapy than in single usage of ICI (chi-square test p=0.0018). There is no difference in irAE frequency between combination therapy and single usage of ICI limited to first line treatment, 52 patients, any/grade 3 or higher in 26 (50%)/10 (19.2%). Treatment duration was tend to longer in the first line treatment including combination therapy and single use of ICI than in the later line treatment (mostly single use of ICI). That may be the reason of the difference of the irAE frequency. Chemoradiotherapy followed by ICH maintenance therapy frequently developed radiation pneumonitis, which was usually NOT included in irAE. irAE could be occurred frequently in especially in combination ICI therapy. It is important to manage the irAE leading better patient outcome.