Phase I study of safety and immunogenicity of ADU-623, a live-attenuated Listeria monocytogenes vaccine (ΔactA/ΔinlB) expressing EGFRvIII and NY-ESO-1, in patients with WHO grade III/IV astrocytomas.

TPS3106 Background: The neo-antigen EGFRvIII is expressed in multiple tumor types, including high-grade astrocytomas. It is associated with a poor prognosis and resistance to conventional therapies such as chemotherapy and radiation that are part of the standard treatment. We propose that immunization with a live-attenuated Listeria-based vaccine, ADU-623, expressing EGFRvIII and NY-ESO-1 will elicit robust tumor-specific immune responses capable of killing EGFRvIII and/or NY-ESO-1-expressing tumor cells and improve survival of the patients. In addition, ADU-623 induces a potent innate immune response that can kill transformed cells even in the absence of neo-antigens. We designed a translational vaccine study to evaluate the safety and immunogenicity of this vaccine in patients with high-grade astrocytomas after standard of care therapy or at progression. Methods: Patients with a pathologic diagnosis of WHO Grade III/IV astrocytic tumors that have completed standard of care external beam radiation therap...