Alternative predictive end points for overall survival (OS), such as tumor response and progression-free survival (PFS), are useful in the early detection of drug efficacy; however, they have not been fully investigated in patients with advanced NSCLC treated with anti–programmed death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) antibodies.Methods
In a systematic review of the reported prospective clinical trials, data for response rate, median PFS, and median OS were extracted from 12 arms in 10 reported clinical trials using anti–PD-1/PD-L1 antibody, and their correlation was investigated. In a retrospective analysis at our institution, OS was compared according to tumor response on 5- to 9-week computed tomography scans and status of being progression-free at 8, 16, and 24 weeks by landmark analysis in 71 patients with advanced NSCLC treated with anti–PD-1/PD-L1 antibodies between 2013 and 2015.Results
In a systematic review, moderate correlations between median OS and median PFS (p = 0.120, r = 0.473) and between median OS and response rate (p = 0.141, r = 0.452) were identified using the Spearman correlation coefficient, although these correlations were not statistically significant. In a retrospective analysis of patients treated at our institution, disease control (partial response [PR]/stable disease versus progressive disease/not evaluable), and progression-free status at 8, 16, and 24 weeks significantly predicted OS (Cox proportional hazards model, PR/stable disease versus progressive disease/not evaluable, p = 0.0104, HR = 3.041; 8-week progression-free yes versus no, p = 0.0183, HR = 2.684; 16-week progression-free yes versus no, p = 0.0036, HR = 4.009; and 24-week progression-free yes versus no, p = 0.0002, HR = 12.726).Conclusions
Both disease control (PR plus stable disease status) and landmark progression-free survival were correlated with OS, with the longer interval landmark PFS being the best predictor of survival in patients with NSCLC treated with anti–PD-1/PD-L1 antibodies.