Abstract
INTRODUCTION: Durvalumab consolidation therapy is the standard of care after concurrent chemoradiotherapy (CRT) for stage III NSCLC. Immune-related pneumonitis during durvalumab treatment is potentially fatal; however, information is lacking regarding the impact of pneumonitis on patient survival. This study investigates the effect of pulmonary and nonpulmonary immune-related adverse events (irAEs) on the efficacy of durvalumab treatment in patients with stage III NSCLC. METHODS: We retrospectively assessed 158 patients who received durvalumab after CRT at nine Japanese institutions between July 2018 and March 2020. Survival outcomes were compared between patients who developed pneumonitis with those who developed irAEs other than pneumonitis. Patients who survived for less than 3 months were excluded to reduce immortal time bias. RESULTS: Among 158 evaluated patients, 76 (48%) experienced grade less than or equal to one irAEs, whereas 82 (52%) experienced grade greater than or equal to two irAEs. Among the patients with grade greater than or equal to two irAEs, those with grade greater than or equal to two pneumonitis (n = 55) were compared with those with grade greater than or equal to two irAEs other than pneumonitis (n = 27). Patients with grade greater than or equal to two pneumonitis exhibited a significantly worse overall survival than those with grade greater than or equal to two irAEs that excluded pneumonitis. Multivariate analysis revealed that grade greater than or equal to two pneumonitis (hazard ratio = 3.71; 95% confidence interval, 1.85-7.45; p < 0.001) and squamous histology (hazard ratio = 2.64; 95% confidence interval, 1.29-5.42; p = 0.008) were independently associated with worse overall survival. CONCLUSIONS: After minimizing immortal time bias, pneumonitis grade two or greater and squamous histology were poor prognostic factors in patients who received consolidation durvalumab after CRT.