Platinum Re-Exposure as a Non-Small Cell Lung Cancer (NSCLC) Treatment Strategy in the Age of Immunotherapy

Abstract

IntroductionImmunotherapy has prolonged the time that NSCLC patients are off platinum-based (PB) chemotherapy. However, the significance of the platinum-free-interval (PFI) is unclear. We evaluated whether an optimal PFI exists in NSCLC for PB re-exposure in contemporary treatment settings. MethodsWe conducted a retrospective cohort study of patients with metastatic NSCLC treated with 1st-line PB chemotherapy with or without immunotherapy. Using multivariable Cox models stratified by treatment strategies, we evaluated whether salvage PB vs. nonPB chemotherapy resulted in superior outcomes and whether this was modulated by the PFI. ResultsA total of 751 patients treated with salvage chemotherapy after PB chemoimmunotherapy were identified in 2 treatment strategy cohorts: 3rd-line after sequential chemotherapy and immunotherapy (Sequential Chemo IO, n = 604); 2ndline after chemoimmunotherapy (Concurrent ChemoIO, n = 147). An optimal PFI of 5 and 6 months was identified in the Sequential Chemo IO and Concurrent ChemoIO cohorts, respectively, but there was no overall survival or progression free survival advantage for PB vs. nonPB chemotherapy in long or short PFI groups. ConclusionAn optimal PFI was identified in this contemporary NSCLC cohort treated with two common immunotherapy-containing treatment approaches, but PFI threshold did not predict benefit from platinum re-exposure as it has in other malignancies.