Tumor-associated antigens and hotspot neoantigens (OST-503) (OST-503 antigens)

Tumor-associated antigens and hotspot neoantigens (OST-503) represent a specific panel of 22 immunogenic targets utilized in the OST-503 (formerly ADXS-503) cancer immunotherapy platform [3.1.1, 3.3.3]. This panel consists of 11 shared hotspot mutations—notably covering all KRAS G12 position mutations (G12D, G12V, G12R, G12C, etc.) as well as common TP53 and EGFR alterations—and 11 proprietary tumor-associated antigens (TAAs) frequently expressed in non-small cell lung cancer (NSCLC) [2.4.1, 3.3.3]. These antigens are designed as off-the-shelf targets to provide broad therapeutic coverage across patients with common oncogenic drivers [3.3.2]. The biological role of these antigens in the context of OST-503 therapy is to serve as the focal point for a robust, vaccine-induced immune response. The antigens are delivered via a live-attenuated Listeria monocytogenes vector, which naturally targets antigen-presenting cells and provides intrinsic adjuvant properties [2.4.3, 3.3.2]. This leads to the generation of potent CD8+ T-cell responses directed against tumor cells that present these specific neoepitopes and TAAs [3.1.2]. OST-503 is currently being evaluated in clinical trials for NSCLC, glioblastoma, and pancreatic cancer, often in combination with pembrolizumab to enhance the anti-tumor immune response and overcome checkpoint inhibitor resistance [2.4.1, 3.3.4].

Other names

ADXS-503 antigensADXS-HOT antigensNSCLC-associated tumor antigensMulti-neoantigen vector targets

Induction of antigen-specific CD8+ T-cell responses via a live-attenuated Listeria monocytogenes vector delivery system that secretes antigen-adjuvant fusion proteins.