Napsin A-specific T-cell clonotypes are associated with improved clinical outcomes in patients receiving checkpoint immunotherapy for metastatic non-small cell lung cancer.

Abstract

Background: Napsin A is normally expressed in human lung pneumocytes and is a highly expressed cancer antigen in lung adenocarcinoma. We examined whether T cells specific for Napsin A may play a role in immune checkpoint inhibitor (ICI)-mediated responses. We used bulk T-cell receptor (TCR) repertoire data to assess whether the presence of Napsin A-specific clonotypes in the peripheral blood was associated with improved clinical responses to ICI.

Methods: Patients with metastatic non-small cell lung cancer (NSCLC) receiving anti-programmed cell death protein 1 (PD-1) and/or programmed death-ligand 1 (PD-L1) were enrolled at Fred Hutchinson Cancer Center and Stanford University Medical Center (n=62; histology of adenocarcinoma n=48, squamous n=9, NSCLC/other n=5). Peripheral blood mononuclear cells were collected for genomic DNA isolation at one pretreatment and one post-treatment time point (range 3 weeks to 3 months). TCRβ was bulk sequenced via the immunoSEQ platform (Adaptive Biotechnologies). Napsin A-specific TCRβ sequences were identified from publicly available data and their frequencies were quantified in each patient sample. We examined whether overall survival (OS) and progression-free survival (PFS) outcomes differed in patients with or without detectable Napsin A-specific TCRs (herein Napsin TCRs). We used Cox proportional hazards regression to assess the association between detectable Napsin TCRs and PFS or OS in univariable and multivariable analyses.

Results: Napsin TCRs were detectable in the blood in a large fraction of our cohort (n=25/62 (40%) pretreatment; n=21/42 (50%) post-treatment). Patients with detectable Napsin TCRs had a significant improvement in OS compared with patients without these TCRs (median OS 45.4 vs 14.8 months, p=0.0043 pretreatment; median OS 55.4 vs 18.9 months, p=0.0066 post-treatment). Among 27 HLA-A*02 carriers of 55 human leukocyte antigen-typed patients (49%), patients with detectable pretreatment Napsin TCRs had a significant improvement in OS (median 60.2 vs 16.5 months, p=0.0054) and PFS (median 21.5 vs 7.2 months, p=0.031) compared with patients without these TCRs. In univariate and multivariate analysis, the presence of Napsin TCRs pretreatment was associated with improved OS (p=0.0057, HR 0.40, 95% CI 0.21 to 0.76 univariate; p=0.033, HR 0.45, 95% CI 0.23 to 0.91 multivariate).

Conclusions: Napsin TCRs are frequently detected in patients with NSCLC and are associated with improved OS in patients with NSCLC receiving ICI.