Our summary
While tumor mutational burden (TMB) is an emerging biomarker that may be associated with response to immune checkpoint inhibitor therapies, the prognostic value associated with TMB in the absence of immunotherapy is uncertain.
This study sought to assess the prevalence of high TMB and its association with overall survival among patients with the same tumor types as the clinical trial cohort but who hadn’t been treated with immunotherapy.
Why this matters
While immune checkpoint inhibitors have revolutionized cancer therapy, the understanding of how to optimize patient selection for treatment with immunotherapy is still evolving. The potential role of tumor mutational burden (TMB) in this regard continues to be an area of active investigation.
In order to validate TMB as a biomarker, specifically predictive of benefit with immune checkpoint inhibitors, investigators have to first characterize the overall prognostic effect (if any) that this marker may have. This report addresses that stepping stone; by determining that TMB in and of itself appears not to have any influence on outcomes, it will be easier to attribute outcome differences associated with high or low TMB in patients treated with immune checkpoint inhibitors to the specific interaction between the marker and this therapeutic class.