Seasonal impact of anti–PD-1 treatment initiation in non-small cell lung cancer patients.

Abstract

e20617 Background: Daily and annual variation of immune parameters has been described (Wyse et al., 2021). We and others have correlated the time-of-day of immune checkpoint inhibitor (ICI) administration with clinical outcomes in different tumor types (Landré et al., 2024; Vilalta et al., 2021), but scarce data is available regarding the seasonal impact (Cho et al., 2024; Ellebaek et al., 2023). We aim to determine if the season of anti-PD-1 initiation is associated with survival outcomes in non-small cell lung cancer (NSCLC) patients receiving anti-PD-1 treatment. Methods: We retrospectively evaluated patients with stage IV NSCLC treated with anti-PD-1 antibodies at three Spanish hospitals (Fundación Jiménez Díaz, Hospital Universitario de Navarra and Clínica Universidad de Navarra) between May 2013 and December 2021. Season of anti-PD-1 initiation was categorized as summer (March 21 st – September 20 th ) versus winter (September 21 st – March 20 th ) according to weather patterns and daylight hours in our country. Kaplan-Meier survival curves of progression-free survival (PFS) and overall survival (OS) were analyzed according to season group. The association between season of ICI initiation and PFS and OS was calculated by Cox regression models. Results: The study included 345 patients treated with Nivolumab or Pembrolizumab monotherapy (255, 73.9%) or in combination with platinum-based chemotherapy (89, 25.8%). Mean age was 64.7 years old (SD 10.0), being 241 patients (69.9%) male. Most patients (200, 58%) received anti-PD-1 therapy as first line, 103 (29.9%) as second line and 42 (12.2%) as third line or beyond. Histology was squamous for 84 patients (24.5%) and 259 (75.5%) had non-squamous NSCLC. A total of 163 patients (47.3%) initiated treatment during the summer period and 182 (52.7%) during winter. Median PFS and OS were 7 months (95%CI 4.7 – 10.6) and 23.8 months (15.5 – 33.1) in the summer group and 5.4 months (3.5 – 6.5) and 16.1 months (12.7 – 24.3) in the winter group, respectively. Multivariate analyses identified summer season as a significant and independent predictor for longer PFS, HR 0.72 (0.55 – 0.93), p = 0.013, with no significant differences in OS. Other correlation analyses are currently being conducted. Conclusions: The initiation of anti-PD-1-based treatment during the summer season was associated with a significant increase in progression-free survival in NSCLC patients.