Impact of Baseline Clinical Biomarkers on Treatment Outcomes in Patients With Advanced NSCLC Receiving First-line Pembrolizumab-Based Therapy

Background: While the introduction of immune checkpoint inhibitors (ICI) such as pembrolizumab has significantly improved survival for patients with metastatic non-small cell lung cancer (NSCLC), there remains a need for improved predictive and prognostic biomarkers.

Patients and methods: We conducted a retrospective, 3-center study using electronic medical record data for patients with stage IV NSCLC treated with first-line pembrolizumab, either as monotherapy or in combination with chemotherapy, between 2014 and 2019. We categorized variables as covariates or confounders. Covariates, which were the focus of analysis due to their emerging prognostic value, included pretreatment body mass index (BMI), neutrophil-to-lymphocyte ratio (NLR), albumin, and antibiotic exposure. Confounders, which highlighted characteristics for each patient and their cancer, included sex, age at start of immunotherapy, Programmed death-ligand 1 (PD-L1) expression, performance status (PS), tumor mutational burden and whether pembrolizumab was given as monotherapy or in combination with chemotherapy. The association between these variables with time to treatment failure (TTF) and overall survival (OS) was assessed using Kaplan-Meier method and Cox proportional hazards models.

Results: One hundred thirty-six patients were included in our study. Antibiotics usage, serum albumin, and NLR have univariate relationships with TTF. Serum albumin, NLR, and BMI were associated with OS in univariate analyses. In our multivariate analysis, antibiotic usage had a strong negative association with TTF when adjusting for all 6 confounders.

Conclusion: Pretreatment usage of antibiotics, as well as albumin, NLR, and BMI have potential to predict treatment outcomes in patients with advanced NSCLC receiving first-line immunotherapy.