In this exploratory analysis, the predictive value of TMB and inflammatory biomarkers (TcellinfGEP, PD-L1) were assessed in both KEYNOTE-012 cohorts (B1 and B2). The methods used to analyze TMB, NL, and TcellinfGEP have been reported.16 18 (link) The cut-off of −0.318 used to define GEPlow and GEPnonlow is synonymous with GEPlo and GEPhi used in Cristescu et al.18 (link) Tumor PD-L1 expression was assessed by IHC combined positive score (CPS); CPS ≥1 was considered positive.
HPV status was confirmed by p16 IHC using the CINtec p16 Ventana assay on the BenchMark Ultra using formalin-fixed paraffin-embedded pretreatment clinical specimens and by WES of germline and tumor DNA. For HPV status determined by p16 IHC, HPV-positive status (defined as ≥70% tumor cells with positive nuclear and/or cytoplasmic diffuse staining and H score of 210) included patients with primary tumor locations in the oropharynx, and HPV-negative status included patients with non-HPV-associated oropharyngeal cancers and primary tumor locations outside the oropharynx. Additional details are described in online supplemental file 1.