Effect of first-line pembrolizumab treatment in individuals with advanced non-small cell lung cancer and poor performance status.

Abstract

e18796 Background: There is limited evidence supporting the optimal use of immune checkpoint inhibitors (ICIs) in NSCLC patients with poor performance status (PS), as clinical trials exclude these patients. In this study, we use real-world oncology data to determine the impact of first line pembrolizumab vs. no treatment in high PD(L)-1 expressing cancers in individuals with advanced NSCLC and ECOG PS ≥2. Methods: We performed a retrospective cohort study of patients with advanced NSCLC with ECOG PS ≥2 between 09/01/2014 and 02/18/2020, using the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database. Patients were included if they were PD(L)-1 high (≥50%) and had clinical and treatment information recorded within 90 days of diagnosis. Real-world overall survival (rwOS) was defined as time from diagnosis to death (censored at last EHR activity). Median rwOS was estimated using weighted Kaplan-Meier methods. A marginal Cox structural model with inverse probability of treatment weighting was used to adjust for selection bias and estimate the effectiveness of pembrolizumab. The inverse probability weights were estimated using an ensemble machine learning technique, Super Learner, based on age, gender, race, practice type and smoking history. Adjusted hazard ratios (aHR) were estimated using weighted Cox proportional hazards models. Stratified analysis was conducted by ECOG PS (2 vs >2). Results: 217 (16%) individuals with advanced NSCLC and high PD(L)-1 expression received no treatment, compared to 546 (39%) individuals who received 1L pembrolizumab. The no-treatment group had a lower proportion of ECOG 2 compared to the pembrolizumab group (Table). Median rwOS in the no-treatment group was 2.4 months, compared to 7.1 months in the pembrolizumab group (p<0.001). In unadjusted survival analyses in the entire cohort and in cohorts stratified by ECOG status, treatment with pembrolizumab was associated with a significantly lower risk of death (hazard ratio [HR]: 0.38, 95% Confidence Interval [CI]: 0.31-0.45). In adjusted analyses, individuals treated with pembrolizumab had improved survival (HR: 0.40, 95% CI: 0.35-0.45). Conclusions: Our analysis of real-world clinical oncology data demonstrated that 1L treatment with pembrolizumab was associated with significantly improved rwOS among individuals with ECOG ≥ 2. [Table: see text]