Abstract LB-095: HPV E7 antigen-expressing Listeria-based immunotherapy (ADXS11-001) prior to robotic surgery for HPV-positive oropharyngeal cancer enhances HPV-specific T cell immunity

Abstract

Human papilloma virus-associated oropharyngeal cancer (HPVOPC), which accounts for almost 75% of newly diagnosed OPC, is an appealing target for immunotherapy due to the expression of viral antigens. ADXS11-001, a live attenuated Listeria monocytogenes listeriolysin O (LLO) immunotherapeutic agent expressing an HPV16-E7 fusion protein, has been shown to induce HPV-specific T cell responses in animal models, and to have clinical activity in cervical cancer. A phase II “window of opportunity” trial was designed to evaluate the effect of ADXS11-001 on anti-tumor immunity in peripheral blood and the tumor immune microenvironment (TIME) of patients with HPVOPC. Previously untreated, surgically resectable, stage II-IV, HPVOPC patients received two doses of ADXS11-001 over 5 weeks prior to transoral robotic surgery. Formalin-fixed paraffin embedded (FFPE) pre-treatment biopsies and post-treatment surgical resection specimens were banked for studies of the TIME. Peripheral blood samples were collected at multiple time points before, during and after ADXS11-001 administration and after surgery. The TIME was profiled by quantitative multiplex immunofluorescence (qIF) microscopy and conventional H&E histopathology. T cell immune responses in the peripheral blood were monitored by ELISPOT of IFN-γ and TNF-α expressing T cells. Serum expression of 38 cytokines was measured using the Luminex multiplex analysis platform. So far 8 patients have completed treatment, of which 5 showed increased E6 or E7-specific IFN-γ responses on the day of surgery or 5 weeks post-surgery, compared to pre-treatment responses. Serum cytokines CCL22 and CXCL10 showed a trend towards increase after ADXS11-001 delivery (p = 0.067, p = 0.070) and drop following surgery (p = 0.069, p = 0.016). CCL22 levels were correlated with E6-specific T cell response after immunotherapy treatment (R2 = 0.6303, p = 0.019). qIF results demonstrated increased post-treatment CD8 and CD4 intratumoral T cell infiltration in 4/8 patients, and correlations between intra-tumoral pre- and post-treatment CD8 numbers (R2 = 0.6481, p = 0.0167). Also, post-treatment PD-1 expression strongly correlated with PD-L1 expression (R2 = 0.8803, p = 0.0007) in the tumor. Tumor infiltrating lymphocytes at the tumor host interface tended to increase after treatment (p = 0.188) and correlated with pre-treatment numbers (R2 = 0.772, p = 0.042). Antigen-specific peripheral blood T cell responses are increased post-treatment with ADXS11-001 and correlate with increased serum CCL22 levels. In this small patient sample (n = 8), the intratumoral qIF and H&E results present an overall suggestion of positive treatment-induced effects in the TIME, which must be confirmed as additional patients are accrued. Citation Format: Rosemarie Krupar, Naoko Imai, Brett Miles, Eric Genden, Krzys Misiukiewicz, Yvonne Saenger, Elizabeth G. Demicco, Jigneshkumar Patel, Phapichaya Chaoprang Herrera, Falguni Parikh, Michael Donovan, Seunghee Kim-Schulze, Marshall Posner, Sacha Gnjatic, Andrew G. Sikora. HPV E7 antigen-expressing Listeria-based immunotherapy (ADXS11-001) prior to robotic surgery for HPV-positive oropharyngeal cancer enhances HPV-specific T cell immunity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-095.

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