Is there an Exposure-Response Relationship for Nivolumab in Real-World NSCLC Patients?

Pharmacokinetic/pharmacodynamic data from real-world cohort are sparse in non small-cell lung cancer (NSCLC) patients treated with nivolumab. The aim of this prospective observational study was to explore the exposure-response relationship for effectiveness and toxicity of nivolumab in 81 outpatients with metastatic lung cancer. Nivolumab plasma trough concentrations (Cmin) were assayed at days 14, 28, and 42. Prognostic factors (including Cmin) regarding progression-free survival (PFS) and overall survival (OS) were explored using a multivariate Cox model. A Spearman's rank test was used to investigate the relationship between Cmin and grade >2 immune-related adverse events (irAE). Mean nivolumab Cmin was 16.2 ± 6.0 µg/mL (n = 76), 25.6 ± 10.2 µg/mL (n = 64) and 33.4 ± 11.3 µg/mL (n = 53) at days 14, 28, and 42, respectively. No pharmacokinetic/pharmacodynamic (PK/PD) relationship was observed with either survival or onset of irAE. Multivariable Cox regression analysis identified Eastern Cooperative Oncology Group Performance Status (hazard ratio 1.85, 95%confidence interval 1.02-3.38, p-value = 0.043) and baseline use of corticosteroids (HR 8.08, 95%CI 1.78-36.62, p-value = 0.007) as independent risk factor for PFS and only baseline use of corticosteroids (HR 6.29, 95%CI 1.46-27.08, p-value = 0.013) for OS. No PK/PD relationship for nivolumab was observed in real-world NSCLC patients. This supports the recent use of flat dose regimens without plasma drug monitoring.