Impact of Lymphopenia Recovery After Chemoradiotherapy on Durvalumab Consolidation Therapy in Stage III NSCLC

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.