Preclinical data suggest a dual therapeutic opportunity. Data reported in the Nature publication indicate that PD - 1 and PLA2G2D are non redundant and reciprocally regulated. More importantly, blockade of PLA2G2D not only restores anti - tumor immunity in preclinical models resistant to anti - PD - 1 therapy but also potentiates the activity of anti - PD - 1 in tumor types that are otherwise unrespon sive to checkpoint inhibition. Together, the Nature findings on PLA2G2D point to two potential paths for patient benefit: a new therapeutic option for patients who have failed anti - PD - 1 therapy, and a way to extend the reach of anti - PD - 1 into tumors currently cons idered “ cold. ” Apeximmune built an antibody against PLA2G2D. AI - 306, the company's lead product candidate, is a first - in - class monoclonal antibody that blocks both the enzymatic and non - enzymatic activity of PLA2G2D. B acked by key patents covering target antagonism, antibody constructs, and combination therapies, AI - 306 is currently in IND - enabling development with cell line development underway. GLP toxicology studies are scheduled to initiate in late 2026, and an IND filing is targeted for the second quarter of 2027. Apeximmune has developed proprietary PLA2G2D knockout and humanized mouse models that support the program. Quotes: Li - Fen Lee, PhD, f ounder and CEO of Apeximmune. “For nearly a decade, we have pursued PLA2G2D based on a conviction that the field was overlooking a fundamentally different kind of immune checkpoint. The independent identification of the same target by the Erasmus team, using entirely different methods and starting from patient samples rather than computational discovery, is the strongest possible validation of the underlying biology. What matters most is what this means for patients: a potential new therapeutic path for the majority who do not respond to anti - PD - 1, and possibly a way to make PD - 1 therapy work in tumor types where it currently cannot.” Floris Dammeijer, MD, PhD, Erasmus MC. “ When we began this work, we were asking a straightforward question: how do cancer cells block effective anti - tumor immune responses where they are first generated, in the lymph node? The answer, unexpectedly, kept pointing to PLA2G2D . ” Ralph Stadhouders, PhD, Erasmus MC. “Discovering that a team at Apeximmune had independently reached the same target , from an entirely different starting point , was extraordinary. The collaboration that followed has produced a body of evidence neither group could have generated alone . " Dan Ross, managing partner at BioPharma Capital and advisor to Apeximmune. “This publication marks an inflection point for Apeximmune and the AI - 306 program. We are actively engaging with partners who share our commitment to bringing this therapy to patients as quickly as possible.” About Apeximmune Therapeutics, Inc.: Apeximmune Therapeutics, Inc. is an IND - stage biotechnology company in South San Francisco, Calif., focused on developing novel immunotherapies for patients who do not respond to existing immune checkpoint inhibitors. Founded by Li - Fen Lee, PhD, the compan y applies proprietary computational target discovery to identify mechanistically distinct immune checkpoints with the potential to expand the reach of immuno - oncology. For more information, visit www.apeximmune.com . Nature Publication: “ PLA2G2D in tumour - draining lymph nodes regulates anti - tumour immunity. ” Nature . Sept . 9, 2026. DOI: 10.1038/s41586 - 026 - 10954 - 1. Anneloes van Krimpen, Julie Huang, Mike Eterman, Vivian Gerretsen, Michihisa Umetani, Josephine C. Janssen, Menno van Nimwegen, Nina