A T cell receptor β chain-directed antibody fusion molecule activates and expands subsets of T cells to promote antitumor activity.

Abstract

Despite the success of programmed cell death-1 (PD-1) and PD-1 ligand (PD-L1) inhibitors in treating solid tumors, only a proportion of patients respond. Here, we describe a first-in-class bifunctional therapeutic molecule, STAR0602, that comprises an antibody targeting germline Vβ6 and Vβ10 T cell receptors (TCRs) fused to human interleukin-2 (IL-2) and simultaneously engages a nonclonal mode of TCR activation with costimulation to promote activation and expansion of αβ T cell subsets expressing distinct variable β (Vβ) TCR chains. In solution, STAR0602 binds IL-2 receptors in cis with Vβ6/Vβ10 TCRs on the same T cell, promoting expansion of human Vβ6 and Vβ10 CD4+ and CD8+ T cells that acquire an atypical central memory phenotype. Monotherapy with a mouse surrogate molecule induced durable tumor regression across six murine solid tumor models, including several refractory to anti-PD-1. Analysis of murine tumor-infiltrating lymphocyte (TIL) transcriptomes revealed that expanded Vβ T cells acquired a distinct effector memory phenotype with suppression of genes associated with T cell exhaustion and TCR signaling repression. Sequencing of TIL TCRs also revealed an increased T cell repertoire diversity within targeted Vβ T cell subsets, suggesting clonal revival of tumor T cell responses. These immunological and antitumor effects in mice were recapitulated in studies of STAR0602 in nonhuman primates and human ex vivo models, wherein STAR0602 boosted human antigen-specific T cell responses and killing of tumor organoids. Thus, STAR0602 represents a distinct class of T cell-activating molecules with the potential to deliver enhanced antitumor activity in checkpoint inhibitor-refractory settings.

• Authors: Jonathan Hsu, Renee N Donahue, Madan Katragadda, Jessica Lowry, Wei Huang, Karunya Srinivasan, Gurkan Guntas, Jian Tang, Roya Servattalab, Jacques Moisan, Yo-Ting Tsai, Allart Stoop, Sangeetha Palakurthi, Raj Chopra, Ke Liu, E John Wherry, Zhen Su, James L Gulley, Andrew Bayliffe, Jeffrey Schlom
• Journal: Science translational medicine (Sci Transl Med) Vol. 15 Issue 724 Pg. eadi0258 (11 29 2023) ISSN: 1946-6242 [Electronic] United States
• PMID: 38019931 (Publication Type: Journal Article)

Chemical References

• Receptors, Antigen, T-Cell, alpha-beta
• Programmed Cell Death 1 Receptor
• Receptors, Antigen, T-Cell
• Antibodies

Topics

• Humans
• Animals
• Mice
• Receptors, Antigen, T-Cell, alpha-beta (metabolism)
• CD8-Positive T-Lymphocytes
• Programmed Cell Death 1 Receptor (metabolism)
• Receptors, Antigen, T-Cell (metabolism)
• Neoplasms (drug therapy, metabolism)
• Antibodies (pharmacology)