Weighting tumor-specific TCR repertoires as a classifier to stratify the immunotherapy delivery in non–small cell lung cancers

Analysis of T cell receptor (TCR) repertoires may contribute to better understanding of the response to immunotherapy. By deep sequencing of the TCR β chain complementarity-determining regions in the paired biopsies and peripheral blood specimens of 31 patients with non–small cell lung cancer (NSCLC) treated with anti–programmed death 1 (PD-1) or PD-ligand 1 (PD-L1) therapy, we developed a previously unidentified index, the TCR-based immunotherapy response index (TIR index), that estimated the degree of overlap of the TCR repertoire between tumor-infiltrating lymphocytes and circulating PD-1(+)CD8(+)T cells (shared TCR clones). This index correlated with response and survival outcomes of anti–PD-(L)1 treatment. All the TCR sequences of neoantigen-stimulated T cells were included in the shared TCR clones, indicating that TCR clones involved in TIR index estimation represented tumor-specific T cells. Therefore, the TIR index is a feasible approach for assessing tumor-specific TCR and stratifying patients with NSCLC for anti–PD-(L)1 therapy.