Abstract 4644: Real-world outcomes in dual checkpoint inhibitor therapy: A single community center perspective

Abstract Introduction: Immunotherapy using dual checkpoint inhibitors is used to induce an antitumor response towards cancer. The varied response in treatment outcomes for those who receive dual checkpoint may be influenced by many factors. We attempted to interrogate factors impacting response to dual checkpoint inhibitor therapies in a single-center retrospective analysis, with the primary objective of examining how these factors may influence cancer progression. Methods: This single-center retrospective analysis examines patients with documented treatment histories of dual immunotherapy between 2015 and 2023. Additional data collected included: demographics, disease characteristics, additional treatment history, imaging, and next generation sequencing results. The primary endpoint of this study was progression free survival, with the secondary endpoint of overall survival. Patients were excluded from the study if they passed within one month of starting dual immunotherapy, were being treated for more than one form of cancer or had insufficient documentation. Results: In this study, the median age at the start of dual immunotherapy was 65 years old (range 30 to 84). Of the 144 patients examined, 20% were diagnosed with stage II or stage III cancer, 76% were diagnosed with stage IV cancer, and 3.5% had an undetermined stage at the start of dual immunotherapy. The most common diagnoses were melanoma (42%), kidney cancer (29%), and lung cancer (9%). 47% of the patients received 4 doses of dual immunotherapy and the next most common group received 2 doses (22%). 51 of the patients had their tumor mutation burden (TMB) assessed with 31% of the patients in this subgroup determined to have a high TMB. 33 patients had PD-L1 assessed, with 69% having a positive PDL-1 status. 46% of patients had not received prior lines of immunotherapy or chemotherapy while 22% received a single line. There was no significant change in survival found for PDL1 status (p=0.49), TMB (p=0.48), or age (p=0.68). The relationship between doses of dual checkpoint immunotherapy to survival was found to be significant (p < 0.001) when assessed over 8000 days but showed insignificant (p=0.18) when assessed over 2500 days. The number of prior lines to survival also was found to be significant (p=0.0014) when assessed over 2500 days. Conclusions: An increase in cancer survivorship was found to be higher in patients that received more doses of dual checkpoint immunotherapy which may suggest that doses of dual immunotherapy received may increase the lifespan of some individuals with cancer. The small sample size of this study is a limitation to this analysis as well as the limited results for PD-L1 and NGS testing results, including TMB. Citation Format: Victoria Moe, Rachel Elsey, Tobias Meissner, Bing Xu, Yuliang Sun, Crystal Hattum, Casey Williams. Real-world outcomes in dual checkpoint inhibitor therapy: A single community center perspective [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4644.