Tumor mutational burden as a predictive biomarker for non-small cell lung cancer treated with immune checkpoint inhibitors of PD-1/PD-L1

Abstract

Background: The significant clinical benefits of PD-1/PD-L1 immune checkpoint inhibitors (ICIP) in non-small cell lung cancer (NSCLC) have been widely recognized, emphasizing the urgent need for a reliable biomarker. In this study, we find the remarkable capacity of tumor mutational burden (TMB) to serve as an accessible and streamlined indicator.

Patients and methods: We designed a retrospective cohort study, consisting of 600 NSCLC patients treated with ICIP. Association between TMB and overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR) has been explored.

Results: A strong positive correlation between TMB levels and OS, PFS rates, clinical benefit has been found when TMB > = 16(TMB > = 16 mutations/megabase (mut/Mb)). However, when TMB < 16, increasing TMB values did not exhibit a gradual stepwise increase in OS and PFS rates. The median months of OS in the TMB > = 16 and < 16 are 35.58, and 10.71 months respectively with average 12.39 months (p < 0.0001). The median months of PFS in the TMB > = 16 and < 16 are not-obtained, and 2.79 months respectively with an average of 3.32 months (p < 0.0001). The DCR in the TMB > = 16 and < 16 are 71.4% and 44.2% respectively with an average of 47.7% (p < 0.0001). The ORR in the TMB > = 16 and < 16 are 49.4% and 20.8% respectively with an average of 24.5% (p < 0.0001).

Conclusion: The TMB > = 16 shows significantly associated with optimal ICIP treatment outcomes, including higher patient survival rates, delayed disease progression, and significant clinical benefits. These results present the potential of TMB as a promising biomarker candidate for NSCLC patients undergoing ICIP treatment.

Keywords: Biomarker; Immunotherapy; Lung cancer; NSCLC; TMB.