Colorado Head and Neck Cancer SPORE

Abstract This application is being submitted in response to the Notice of Special Interest (NOSI) identified as NOT-CA- 23-059. Sinonasal carcinoma (SC) is an important head and neck cancer (HNC) globally, but prognosis remains poor. SC is understudied in the laboratory and in the clinic. We propose that SC in pet dogs represents a

spontaneous animal model of this HNC. Our team has validated approaches to investigate immunotherapy and stereotactic body radiation therapy (SBRT) in canine SC clinical trials. Our current efforts incorporate myeloid cell targeted immunotherapy (MTI) with two repurposed drugs (losartan and propranolol) to deplete or reprogram

myeloid cells when combined with SBRT. Our early results in dogs with SC treated with the MTI + SBRT protocol provide evidence of enhanced local T cell responses and improved overall survival compared to SBRT alone. The proposed study represents a logical addition to the parent program (Colorado Head and Neck Cancer

SPORE) which seeks to advance translational research to improve survival and quality of life for HNC patients. Our project will therefore be consistent with the overall immunotherapy/radiotherapy SPORE theme. In this study, we propose to expand the canine MTI/SBRT trial with more animals and add new immune monitoring to assess

local and systemic tumor immunity, as well as functional tumor imaging to understand the impact of MTI/SBRT on tumor perfusion. We will test the overall hypothesis that combining MTI with SBRT will significantly increase SC tumor immunity, perfusion, and improve SBRT clinical responses. Results from this MTI/SBRT study can

exert an immediate and substantial impact on the management of human SC, as the 2-drug combination of already approved and safe drugs for MTI can be readily implemented clinically. Specific Aim 1: Determine whether addition of myeloid-targeted immunotherapy (MTI) to SBRT augments local and systemic tumor immunity in dogs with SC. Subaim 1.1 will investigate local tumor immune

responses to SBRT and MTI/SBRT, using tumor biopsy and nasal lavage samples, to include analysis of immune cell infiltrates (immunohistochemistry, flow cytometry) and transcriptional status (scRNA-seq, bulk RNAseq). In Subaim 1.2, regional and systemic tumor immune responses will be examined, using lymph node biopsies (flow

cytometry, RNAseq) and PBMC samples (T cell responses to SC tumor antigens). The clinical impact of combined MTI/SBRT on tumor responses will be assessed in Subaim 1.3 by serial CT evaluation (pre-treatment, 3 mos, 6 mos) and determination of progression-free interval (PFI) and overall survival time (OST) will be

compared between treatment groups. Specific Aim 2: Elucidate the impact of combined MTI/SBRT on tumor perfusion in dogs with SC. Dynamic contrast enhanced-CT will be used in Subaim 2.1 to determine how adding MTI to SBRT affects tumor perfusion parameters at 3- and 6-mos following treatment. In Subaim 2.2, the impact of adding MTI to SBRT on

tumor angiogenesis and vessel architecture will be determined, using serial tumor biopsies and IHC analyses.