Fig. 3. Confirmation of the predictive nature of the immunotherapy response score (IRS) biomarker.
To establish the predictive nature of the IRS model, we assessed an internal comparator in the pembrolizumab monotherapy cohort, consisting of the 146 patients who had received a prior line of systemic therapy prior to pembrolizumab monotherapy (n = 146 individual patients). a For each patient, real-world progression-free survival (rwPFS) was determined for the line of systemic therapy immediately prior to pembrolizumab (pembro; yellow) and the pembrolizumab monotherapy line (purple), with rwPFS for each group then stratified by IRS status. b Kaplan–Meier analysis of pembrolizumab monotherapy rwPFS (purple) vs. prior systemic therapy rwPFS (yellow) in the IRS-Low [L] subset of patients (log-rank p-value shown). The number (n) of patients, events, and median rwPFS (with 95% confidence intervals [CI]) for each group are shown. c Kaplan–Meier analysis of pembrolizumab monotherapy rwPFS (purple) vs. prior systemic therapy rwPFS (yellow) in the IRS-H subset of patients (log-rank p-value shown). The likelihood ratio test (LRT) p-value for interaction between pembrolizumab vs. immediately prior treatment line and IRS status (IRS-L vs. IRS-High [H]) is also shown.