Year: 2026
Type: conference-abstract
Abstract: Background Immune checkpoint blockade (ICB) has improved outcomes for solid malignancies, including advanced melanoma, but the majority of patients do not experience durable disease control. 1 Tumor-infiltrating lymphocyte (TIL) therapy offers a personalized treatment option for ICB-refractory melanoma, leveraging the patient’s own tumor-reactive endogenous T cells expanded from resected tumor material.2 However, lifileucel, the only FDA-approved TIL therapy, fails to induce a clinical response in approximately 70% of patients with metastatic ICB-refractory melanoma, presenting an opportunity to improve patient selection and optimize efficacy.3–5 As predictors of TIL response remain poorly defined, here we systematically interrogate cellular and patient characteristics associated with clinical outcomes.Methods Using single-cell RNA-sequencing (scRNA-seq) with matched T cell receptor sequencing (scTCR-seq), we generated a dataset comprising 827,886 cells from 90 samples, including pre-manufacture tumor biopsies, TIL infusion products (Product), and pre- and post-infusion peripheral blood mononuclear cells from 19 patients with checkpoint-refractory melanoma treated with lifileucel. In addition, spectral flow cytometry analysis enabled detailed immunophenotyping.Results Across 8 responders and 11 non-responders, tumor harvest source, such as lymph node and splenic tissue, may influence pre-manufacture TIL states and, consequently, the cellular composition of the final infusion product. Pre-manufacture tumor TILs from responders were enriched for exhaustion-associated markers TOX, LAG-3, and TIGIT (FDR < 0.001), while non-responder TILs were marked by IL7R (FDR < 0.0001) and KLRB1 (FDR < 0.05). TCR-based reverse fate mapping of 766 paired TIL pre-manufacture and infusion product clonotypes across 20,257 cells showed that intratumoral T cell clones detected in the manufactured product exhibited elevated oxidative phosphorylation signatures relative to undetected clones and displayed a KLR-dependent effector bias (FDR < 0.001), indicating that metabolic fitness and effector programming may govern clonal persistence through manufacturing. In infusion products, T cells from responders with shared tumor-product TCR clonotypes showed rejuvenation from exhaustion signatures, and intratumoral TIL clonotypes detected in Product had elevated XCL1/2 expression, a chemokine axis known to recruit cDC1s. Consistent with this axis, circulating cDC-like monocytes emerged as T cell-extrinsic correlates of clinical response (FDR < 0.01), implicating coordinated myeloid-T cell crosstalk across compartments in shaping therapeutic outcome.Conclusions Multi-compartment single-cell and TCR tracking of lifileucel-treated melanoma identified intratumoral TIL states associated with manufacturing persistence and product features associated with clinical response. Together, these findings nominate candidate biomarkers and provide a foundation for rational TIL optimization, including selection of tumor harvest sites and product formulation strategies to enrich rejuvenation-competent, therapeutically favorable cellular states.References Dana H, Chalbatani GM, Jalali SA, Mirzaei HR, Grupp SA, Suarez ER, Rapôso C, Webster TJ. CAR-T cells: early successes in blood cancer and challenges in solid tumors. Acta Pharm Sin B. 2021 May;11(5):1129–1147. doi: 10.1016/j.apsb.2020.10.020. Epub 2020 Oct 28. PMID: 34094832.Betof Warner A, Hamid O, Komanduri K, et al. Expert consensus guidelines on management and best practices for tumor-infiltrating lymphocyte cell therapy. J Immunother Cancer. 2024;12(2):e008739. doi: 10.1136/jitc-2023-008739.Michielin O, Atkins MB, Koon HB, Dummer R, Ascierto PA. Evolving impact of long-term survival results on metastatic melanoma treatment. J Immunother Cancer. 2020;8(2):e001589. doi: 10.1136/jitc-2020-001589.Betof Warner A, Corrie PG, Hamid O. Tumor-infiltrating lymphocyte therapy in melanoma: facts to the future. Clin Cancer Res. 2023 May 1;29(9):1835–1854. doi: 10.1158/1078-0432.CCR-22-2376.Chesney J, Lewis KD, Kluger H, et al. Efficacy and safety of lifileucel, a one-time autologous tumor-infiltrating lymphocyte (TIL) cell therapy, in patients with advanced melanoma after progression on immune checkpoint inhibitors and targeted therapies: pooled analysis of consecutive cohorts of the C-144-01 study. J Immunother Cancer. 2022;10(12):e005755. doi: 10.1136/jitc-2022-005755.Ethics Approval This study was approved by the Institutional Review Board of Stanford (IRB #43375)
Subfield: Oncology
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,490
OpenAlex ID: W7225203282