Neoantigen-specific stimulation of tumor-infiltrating lymphocytes enables effective TCR isolation and expansion while preserving stem-like memory phenotypes

• Published in: Journal for immunotherapy of cancer Vol. 12; no. 5; p. e008645
• Main Authors: Levin, Noam, Kim, Sanghyun P, Marquardt, Charles A, Vale, Nolan R, Yu, Zhiya, Sindiri, Sivasish, Gartner, Jared J, Parkhurst, Maria, Krishna, Sri, Lowery, Frank J, Zacharakis, Nikolaos, Levy, Lior, Prickett, Todd D, Benzine, Tiffany, Ray, Satyajit, Masi, Robert V, Gasmi, Billel, Li, Yong, Islam, Rafiqul, Bera, Alakesh, Goff, Stephanie L, Robbins, Paul F, Rosenberg, Steven A
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group Ltd 01.05.2024; BMJ Publishing Group LTD; BMJ Publishing Group
• Subjects: Adoptive cell therapy - ACT; Animals; Antigens; Antigens, Neoplasm - immunology; Breast cancer; Cytokines; Dendritic cells; Female; Humans; Immune cell therapies and immune cell engineering; Immunologic Memory; Immunotherapy; Lymphocytes; Lymphocytes, Tumor-Infiltrating - immunology; Lymphocytes, Tumor-Infiltrating - metabolism; Melanoma; Mice; Mutation; Neoplasms - immunology; Patients; Peptides; Phenotype; Receptors, Antigen, T-Cell - immunology; Receptors, Antigen, T-Cell - metabolism; T cell Receptor - TCR; Tumor infiltrating lymphocyte - TIL; Tumor infiltrating lymphocyte - TIL; Adoptive cell therapy - ACT; T cell Receptor - TCR
• ISSN: 2051-1426; 2051-1426
• DOI: 10.1136/jitc-2023-008645

BackgroundTumor-infiltrating lymphocytes (TILs) targeting neoantigens can effectively treat a selected set of metastatic solid cancers. However, harnessing TILs for cancer treatments remains challenging because neoantigen-reactive T cells are often rare and exhausted, and ex vivo expansion can further reduce their frequencies. This complicates the identification of neoantigen-reactive T-cell receptors (TCRs) and the development of TIL products with high reactivity for patient treatment.MethodsWe tested whether TILs could be in vitro stimulated against neoantigens to achieve selective expansion of neoantigen-reactive TILs. Given their prevalence, mutant p53 or RAS were studied as models of human neoantigens. An in vitro stimulation method, termed “NeoExpand”, was developed to provide neoantigen-specific stimulation to TILs. 25 consecutive patient TILs from tumors harboring p53 or RAS mutations were subjected to NeoExpand.ResultsWe show that neoantigenic stimulation achieved selective expansion of neoantigen-reactive TILs and broadened the neoantigen-reactive CD4+ and CD8+ TIL clonal repertoire. This allowed the effective isolation of novel neoantigen-reactive TCRs. Out of the 25 consecutive TIL samples, neoantigenic stimulation enabled the identification of 16 unique reactivities and 42 TCRs, while conventional TIL expansion identified 9 reactivities and 14 TCRs. Single-cell transcriptome analysis revealed that neoantigenic stimulation increased neoantigen-reactive TILs with stem-like memory phenotypes expressing IL-7R, CD62L, and KLF2. Furthermore, neoantigenic stimulation improved the in vivo antitumor efficacy of TILs relative to the conventional OKT3-induced rapid TIL expansion in p53-mutated or KRAS-mutated xenograft mouse models.ConclusionsTaken together, neoantigenic stimulation of TILs selectively expands neoantigen-reactive TILs by frequencies and by their clonal repertoire. NeoExpand led to improved phenotypes and functions of neoantigen-reactive TILs. Our data warrant its clinical evaluation.Trial registration numberNCT00068003, NCT01174121, and NCT03412877.