Prognostic factors of overall survival (OS) in non-small cell lung cancer (NSCLC) patients after failure on immune checkpoint inhibitors (IO) treated with anticancer vaccine OSE2101 or chemotherapy (CT) in phase 3 ATALANTE-1 randomized trial.

Abstract

e21037 Background: OSE2101 (Tedopi) is an anticancer vaccine that has shown an improvement in overall survival (OS) compared with Chemotherapy (CT) (HR 0.59; p = 0.017) in HLA-A2+ NSCLC patients with IO secondary resistance (ESMO 2021 #47LBA). The objective of this analysis was to identify the prognostic factors of OS in each treatment group. Methods: 118 NSCLC EGFR and ALK negative patients who progressed after sequential CT-IO and who received at least 12 weeks IO (defining IO secondary resistance), were randomized (2:1) in OSE2101 or SoC (docetaxel or pemetrexed). Stepwise multivariate analysis of OS was performed after the selection of factors with p > 0.10. Classical baseline factors (disease stage, histology, patient general status) and treatment effect, including best response (Complete Response CR, Partial Response PR, Stable Disease SD versus Progressive Disease PD), severe adverse events and ECOG PS deterioration, were studied and correlated to OS. Results: The statistically significant prognostic factors of OS in multivariate analysis are described in table below. When PS ≤1 was maintained, median OS with OSE2101 was 14.0 [11.1; 16.8] months and 6.3 [2.9; 8.2] when PS deteriorated > 1 (HR 0.23 [0.13; 0.41]); with CT, median OS was respectively 7.5 [4.4; 10.3] and 7.2 [2.3; 15.7] months (HR 0.92 [0.44; 1.96]). When best response to study treatment was CR/PR/SD, median OS with OSE2101 was 12.6 [8.8;16.8] months and 8.0 [5.5; 11.1] when best response was DP (HR 0.61 [0.36; 1.04]); with CT, median OS was respectively 9.8 [7.4; 13.8] and 5.0 [1.0; 7.2] months (HR 0.34 [0.14; 0.84]. Conclusions: Prognostic factors of OS differ between cancer vaccine OSE2101 and standard CT. Maintenance of good ECOG PS was the most important for OSE2101, while best response (CR/PR/SD) to treatment correlated with longer OS with CT and was not prognostic for OSE2101. This analysis supports the mechanism of action of the cancer vaccine in improving OS by controlling tumor growth regardless of best response. Clinical trial information: NCT02654587 . [Table: see text]