The FDA has approved the use of TMB (Tumor Mutation Burden) detection as a biomarker for the selection of pembrolizumab (Keytruda™) as a treatment for adults and pediatric patients with incurable or metastatic solid tumors.
The approval was based in part on phase 2 Trial KEYNOTE-158, which revealed an association between high TMB and ORR response with the PD-1 inhibitor in patients with various solid tumors.
TMB refers to the total number of mutations present in the tumor genome.
Tumors with a high mutation load (TMB-H) may have a higher percentage of neo-antigens and, consequently, are expected to be more immunogenically active than tumors with a comparatively lower mutation load.
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