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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.

Introduction: Durvalumab maintenance therapy after definitive concurrent chemoradiotherapy (CRT) is the standard treatment modality for stage III NSCLC. Although severe treatment-related lymphopenia (TRL) during CRT may impair the efficacy of subsequent durvalumab therapy, data on the effect of TRL recovery on consolidation durvalumab therapy are lacking. Methods: This retrospective study evaluated patients with unresectable stage III NSCLC treated with durvalumab after concurrent CRT. The patients were enrolled across nine institutes throughout Japan between August 2018 and March 2020. The effect of TRL recovery on survival was evaluated. The patients were divided into two groups on the basis of their lymphocyte recovery status: the recovery group involved patients who did not experience severe TRL or experienced TRL but exhibited lymphocyte count recovery at durvalumab initiation, and the nonrecovery group involved patients who experienced severe TRL and did not exhibit lymphocyte count recovery on durvalumab initiation. Results: Among the 151 patients evaluated, 41 (27%) and 110 (73%) patients were classified into the recovery and the nonrecovery groups, respectively. The nonrecovery group had significantly worse progression-free survival than the recovery group (21.9 mo versus not reached, p = 0.018). Recovery from TRL (p = 0.027) and high pre-CRT lymphocyte count (p = 0.028) independently influenced progression-free survival. Conclusions: Baseline lymphocyte count and recovery from TRL at the start of durvalumab therapy were predictive factors for survival outcomes in patients with NSCLC treated with durvalumab consolidation after concurrent CRT.