Abstract A022: Effects of chemotherapy on the peripheral immune-cellome in patients with pancreatic cancer

Abstract Pancreatic cancer (PC) has become one of the leading causes of cancer related deaths. Late detection and resistance to therapy are two reasons for the dismal prognosis of this disease. Hence, there is an immense need for novel treatment options as well as predictive biomarkers, to prolong the life of these patients. The Chemotherapy, Host Response and Molecular Dynamics in Periampullary Cancer, the CHAMP study (clinical trial nr NCT03724994), is an ongoing observational, prospective clinical study that includes newly diagnosed patients with PC or other periampullary cancers receiving adjuvant or first-line palliative chemotherapy. The present study aims to investigate the peripheral immune-cellome in serial blood samples obtained during treatment from 24 patients, of whom 8 had resectable tumors. Buffy coat was isolated from blood samples taken at baseline (before treatment), after one month and after three to four months of treatment. Flow cytometry with two panels of antibodies was applied to detect major immune populations in both the innate and the adaptive immune system, as well as subpopulations of T cells. Immune cell frequencies were compared between patients with progression and no progression during treatment, and the associations of different immune cell subsets with overall survival were examined. As B cells have been highlighted as being of particular clinical relevance, single-cell transcriptomics and proteomics will be applied to further delineate the dynamics and prognostic impact of individual subtypes within this lineage. The results will provide important real-world data on the longitudinal dynamics of circulating immune cells under the pressure of chemotherapy in patients with PC. These results will in the future be related to analyses of circulating tumor DNA in matched blood samples, and together they will provide a foundation for forthcoming adaptive treatment trials based on results from the CHAMP study. Citation Format: Maja Svensson, Alexandra Petersson, Viktor Sincic, Sofie Olsson Hau, Jakob Eberhard, David Gisselsson Nord, Karin Leandersson, Kristina Lundberg, Karin Jirström. Effects of chemotherapy on the peripheral immune-cellome in patients with pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on the Evolutionary Dynamics in Carcinogenesis and Response to Therapy; 2022 Mar 14-17. Philadelphia (PA): AACR; Cancer Res 2022;82(10 Suppl):Abstract nr A022.