PD1-targeted cis-delivery of an IL-2 variant induces a multifaceted anti-tumoral T cell response in human lung cancer

Antibody-cytokine fusion proteins are being developed as next-generation cancer immunotherapies, aiming to deliver activation signals to targeted immune populations. Among these, PD1-IL2v - an engineered interleukin-2 variant (IL-2v) lacking CD25 binding, fused to a high affinity programmed cell death protein-1 (PD-1) blocking antibody - has shown promising results in murine tumor models. Here, using human model systems, we show that PD1-IL2v elicits a multifaceted anti-tumor T cell response by targeting both CD8⁺ and conventional CD4⁺ T cells (Tconv). Single cell RNA sequencing (scRNAseq) on a lung cancer patient-derived tumor fragment (PDTF) platform revealed that PD1-IL2v drives the expansion of proliferative, cytotoxic CD8⁺ T cells exhibiting features of tumor reactivity. This was accompanied by upregulation of CXCR6, enhancing their migratory capacity. In Tconv cells, PD1-IL2v upregulated CXCL13 expression and promoted a Tfh/Th1-like transcriptional program associated with anti-PD1 responsiveness. Our findings provide mechanistic insights into the effects of IL-2v targeted delivery to PD-1⁺ cells within human tumors, supporting the clinical development of next-generation immunocytokines.