Who Benefits the Most From Adjuvant Durvalumab After Chemoradiotherapy for Non-small Cell Lung Cancer? An Exploratory Analysis

Purpose: Adjuvant durvalumab is now recommended for most patients with locally advanced non-small cell lung cancer after concurrent chemoradiotherapy. Herein, we explore the clinical factors that may be associated with the benefit from adjuvant durvalumab. Methods and Materials: Patients with non-small cell lung cancer who were treated with definitive concurrent chemoradiotherapy at our institution between August 2013 and May 2019 were included in this analysis. Clinical and treatment characteristics were tested for associations with progression-free survival (PFS) in Cox models. Interaction terms were added to the PFS Cox models to explore factors that may modulate the effects of adjuvant durvalumab. PFS and overall survival (OS) rates were estimated using the Kaplan-Meier method, and comparisons between patient subgroups were performed using log rank testing. Results: A total of 105 patients met the eligibility criteria. Thirty-five patients (33%) received adjuvant durvalumab. Treatment with durvalumab was associated with significant improvement in PFS (1-year PFS: 67% vs 39%; log rank P = .006) and OS (1-year OS: 88% vs 76%; log rank P = .041). Exploratory analyses identified the neutrophil-to-lymphocyte ratio (NLR) after radiation therapy (RT) as a factor that may be associated with a benefit from durvalumab. For patients with post-RT NLR exceeding the cohort's median value of 4.3, receipt of adjuvant durvalumab was not associated with a significant PFS improvement (1-year PFS: 45% vs 36%; log rank P = .702). For patients with post-RT NLR <4.3, durvalumab receipt was associated with improved PFS (69% vs 41%; P = .009). High mean RT doses delivered to the heart and esophagus were associated with high post-RT NLR. Conclusions: We identified low NLR after chemoradiotherapy as a factor that may be associated with a benefit from adjuvant durvalumab. Validation studies are warranted.