Overall survival in high and very high PD-L1 expressing patients with advanced non-small cell lung cancer treated with immune checkpoint inhibitors in a real-world data setting.

Abstract

e15156 Background: Clinical trials show improved survival for advanced non-small cell lung cancer (aNSCLC) patients whose tumors are positive for PD-L1 expression when treated with immune checkpoint inhibitors (ICI), including pembrolizumab (Pb) and nivolumab (Nb). It is unclear whether relatively higher PD-L1 expression by tumor proportion score (TPS) is associated with better response to treatment, and whether this can be generalized to a real-world setting. Methods: We assessed overall survival (OS) across categories of PD-L1 expression levels among aNSCLC patients who received ICI monotherapy in the advanced/metastatic setting (stages IIIB or IV, or documented metastatic disease at diagnosis). Sub-analyses were performed based on first, second, or subsequent lines of treatment, as well as for patients receiving only Pb. The patient population is a sample from community health systems based in the United States, with data derived from electronic medical records and supplemented with molecular data integration from diagnostics labs. Results: 874 aNSCLC patients received ICI in the advanced/metastatic setting in the first line (n = 246, 28%), second line (n = 456, 52%), or third or later lines (n = 172, 20%). ICI-treated patients in any line with TPS of 1-49% (n = 148), 50-89% (n = 124), and 90-100% (n = 97) had OS of 6.9, 11.5, and 11.7 months, respectively. Pb-treated patients in any line with TPS of 1-49% (n = 38), 50-89% (n = 104), and 90-100% (n = 72) had OS of 5.5, 10.1, and 11.7 months, respectively. ICI-treated patients in the 1st line with TPS of 1-49% (n = 10), 50-89% (n = 80), and 90-100% (n = 59) had OS of 3.7, 8.0, and 7.4 months, respectively. Pb-treated patients in the first line with TPS of 1-49% (n = 7), 50-89% (n = 80), and 90-100% (n = 58) had OS of 3.7, 8.0, and 9.5 months, respectively. Conclusions: Results suggest OS benefit for real-world ICI-treated aNSCLC patients with PD-L1 TPS ≥50%, consistent with observations in clinical trials. The data further suggest additional benefits in the highest TPS category of 90-100% among Pb-treated patients, while the evidence is weaker for all ICI-treated patients, although comparisons did not reach statistical significance. A similar trend was seen in analyses of both patients treated in first-line only and in any line. Further analyses, to include comparison to clinical trial results, are warranted.