MA07.11 Survival Outcomes Based on Gender of Advanced Nonsmall Cell Lung Cancer Patients Treated with Pembrolizumab or Nivolumab in Everyday Clinical Practice

Abstract

Women are underrepresented in clinical trials of PD1 Ab. We investigated the relationship between gender and overall survival (OS) in aNSCLC patients (pts) treated with PD1 Ab in a large Canadian provincial cohort. All aNSCLC pts treated with nivolumab (NIV) or pembrolizumab (PEM) between 06/2015 and 11/2018 at BC Cancer were identified. Demographic, tumor, treatment details, and survival status were collected from chart review. Kaplan-Meier (KM) curves of OS from initiation of PD1 Ab were generated and compared by the log-rank test. Of 527 pts analyzed (58.9% NIV, 36.1% PEM), 50.5% were female. Women were more likely to have Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0/1 at PD1 Ab initiation (72.9% vs. 64.8%, p=0.05), lower median Charlson Comorbidity Index score (CCI, 2.0 vs. 3.0, p=0.006), and tumors with non-squamous histology (83.5% vs. 69.7%, p<0.001) or Epidermal Growth Factor Receptor (EGFR) mutation (9.8% vs. 3.4%, p=0.006). No significant gender variation in age at diagnosis, smoking status, and programmed death ligand 1 tumor proportion score (PD-L1 TPS) was observed. In addition, there were no differences in type of PD1 Ab, line of treatment, duration of treatment, or treatment discontinuation due to immune related adverse events. With a median follow-up of 16.3 months by reverse KM method, 65% of pts had died. In the entire cohort, women had a longer median OS than men (10.2 vs. 8.1 months, p=0.029). In the subgroup of ECOG PS 2/3 pts, men had worse OS (3.9 vs. 6.5 months, p=0.034). Women ≥60 years of age at initiation of PD1 Ab demonstrated superior median OS to men (12.2 vs. 6.1 months, p=0.006). On multivariable analysis of NIV pts, male gender (HR=1.3, 95% CI 1.0-1.7, p=0.02), baseline ECOG PS 2/3 (HR=2.5, 95% CI=1.9-3.2 p<0.001), CCI score≥3 (HR=1.6, 95% CI=1.3-2.1, p<0.001), and EGFR/ALK aberration (HR=2.3, 95% CI 1.4-3.9, p<0.001) predicted for worse survival; for PEM pts, only ECOG PS 2/3 (HR=2.5, 95% CI 1.6-3.9, p<0.001) was associated with OS. In this large series with a significant proportion of women, females treated with PD1 Ab for aNSCLC lived longer than men (especially if ECOG PS 2/3 or age≥ 60 years.) Despite similarities in smoking status and PD-L1 TPS, gender divergence in outcome could be attributed to more favorable histology and baseline ECOG PS in females. Increased enrollment of women in PD1 Ab trials would facilitate evaluation of gender as a predictive variable.