Abstract 1699: Impact of whole blood interferon gamma production for patient selection in vaccination with autologous formalin-fixed tumor vaccine

Abstract

Abstract Introduction: Immune checkpoint blockade by anti-CTLA-4 antibody and anti-PD-1 antibody led to clinical breakthrough for the treatment of patients with solid tumors. Moreover, recent reports have shown that neoantigens are important functional targets mediating response to immune checkpoint inhibitors. Therefore, sequential combination of personalized cancer vaccines and immune checkpoint blockade has emerged as a potential therapeutic strategy. However, existing drawbacks is that it is difficult to identify robust biomarkers for patient selection in vaccination with cancer vaccine. In this study, we examined whether the development of delayed-type hypersensitivity (DTH) response, measured after vaccination with autologous formalin-fixed tumor vaccine (AFTV), correlates to parameters of immune function such as whole blood cytokine levels and peripheral regulatory T cells (Treg) in patients with solid tumors. Methods: Subjects comprised 52 patients with solid malignancy. AFTV treatment consisted of 3 courses of vaccination performed at intervals of 2 weeks. DTH test was performed before and after vaccination. A positive DTH response was defined as a ≥ 10mm diameter erythema/induration. We evaluated whole blood cytokine production after phytohemagglutinin (PHA) stimulation using the bioplex array system. We also assessed the number of peripheral Tregs as well as routine hematological and biochemical parameters. Results: DTH positive patients and DTH negative patients did not differ with respect to the number of peripheral Tregs, leukocytes, lymphocytes or granulocyte/lymphocyte ratio. Whole blood IFN-γ production levels after phytohemagglutinin (PHA) stimulation at baseline in DTH positive patients were significantly higher than those in DTH negative patients (p=0.0397). Conclusion: These data indicate that whole blood IFN-γ production at baseline is likely to be useful to assess immunologic competence in vaccinated patients with AFTV. Consequently, clinical utility of whole blood IFN-γ production, as immunomonitoring method for patient selection in vaccination with cancer vaccine, is required to investigate in larger clinical studies in the future. Citation Format: Naoyuki Sakamoto, Takeshi Ishikawa, Tetsuya Okayama, Tomoyo Yasuda, Toshifumi Doi, Mari Tanigawa, Yuji Naito, Yoshito Itoh, Toshikazu Yoshikawa. Impact of whole blood interferon gamma production for patient selection in vaccination with autologous formalin-fixed tumor vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1699. doi:10.1158/1538-7445.AM2017-1699