Imaging tumor-infiltrating CD8+ T-cells in non-small cell lung cancer patients upon neo-adjuvant treatment with durvalumab

ABSTRACT

Aim/Introduction: Immune checkpoint inhibitors (ICI), like targeting programmed death receptor ligand 1 (PD-L1), have revolutionized anti-cancer treatments, including non-small cell lung cancer (NSCLC) [1, 2]. Assessment of PD-L1 expression on tumor biopsies is current practice, but there is a need for additional biomarkers correlating to the complex mechanism of action of ICI. The presence of tumorinfiltrating CD8+ T-cells (TILs) is a robust biomarker associated with immune therapy success [3]. Tools to track TILs in patients during ICI treatment allow further development of immune-oncology drugs. Material(s) and Method(s) This ongoing single-center prospective study (NCT03853187) includes patients with histologically proven T1b-3N0-1M0 NSCLC eligible for resection. Exclusion criteria are previous anti-cancer therapy and known immune disorders or suppression. Patients receive two courses neo-adjuvant durvalumab (750mg Q2W), after which TIL imaging is performed. Cohort 1 underwent apheresis and magnetic-activated cells sorting to isolate 100 x10e6 autologous CD8+ T-cells for cell labeling with 111In-oxine. Re-injection was followed by 4h post-injection (p.i.) planar imaging, 70h p.i. SPECT imaging, standard-of-care surgery and 78h p.i. uSPECT of the resected lobe. Patients in cohort 2 (ongoing) receive 1.5mg 89Zr-Df-crefmirlimab followed by PET/CT 24h p.i. Result(s) In cohort 1, 8/10 patients underwent apheresis and TIL imaging;one procedure was withdrawn due to COVID-19 restrictions and one due to unsuccessful T-cell isolation. Yield ranged 240-714 x10e6 CD8+ T-cells, purity 84%-97% and cell viability 92%-100%. Labeling efficacy of 100 x10e6 cells for re-injection ranged 42%-64% and injected activity 22,4-36,7 MBq In-111.TIL imaging was completed by 4/5 patients in cohort 2, one subject discontinued neo-adjuvant treatment due to post-obstruction pneumonia.Tumor-to-bloodpool were determined to quantify specific TIL accumulation in the tumor. Our results favor quantification of T-cells on PET over SPECT given its higher sensitivity and spatial resolution. Correlation of imaging findings with density of CD8+ T-cells in the resected tumor is currently ongoing. Conclusion(s) We implemented two methods for tracking CD8+ T-cells in earlystage NSCLC patients after neo-adjuvant durvalumab treatment. Although ex vivo cell labeling perhaps more specifically targets migrating TILs into the tumor, 89Zr-Df-crefmirlimab has the potential to also target residing cells. Quantitative correlation with presence of TILs in the resected tumor will help to determine the role of these imaging tools in the development of immune-oncology drugs.