Impact of tumor mutational burden on checkpoint inhibitor drug eligibility and outcomes across racial groups

The FDA approval of immune checkpoint inhibitors for cancers with tumor mutation burden (TMB) of at least 10 mut/Mb is postulated to reduce healthcare disparities by broadly expanding treatment eligibility. In a cohort of 39,400 patients with available genomic and race data, black and Asian patients were less likely to have TMB-high cancers in multiple types of malignancies based on the currently approved cut-off. Decreasing TMB thresholds preferentially increased the eligibility of minority patients for immune checkpoint inhibitors while retaining predictive value of treatment benefit in a cohort of immune checkpoint inhibitor treated patients. This study highlights differing distributions of TMB-high cancers between racial groups and provides guidance in developing more rational eligibility criteria for immune checkpoint inhibitors.