A pH Responsive Transistor-like Nanoprobe for Sensitive Detection of Unknown Primary Cancers of the Head and Neck Project Summary/Abstract Approximately 65,000 cases of Head and Neck Squamous Cell Cancer (HNSCC) are diagnosed each year in the US and arise in the mucosal lining of the upper aerodigestive tract and spread to local lymph nodes. In some cases, the primary tumor is too small to be detected, with enlarged nodes being the only manifestation of HNSCC. These unknown primary cancers (UPCs), often induced by human papilloma virus (HPV), usually arise in the mucosa of Waldeyer's ring, the lymphatic tonsillar tissues of the pharynx. Finding UPC is significant and impactful addressing an unmet need with long term oncologic and functional outcomes improved by locating and removing UPC. However, their detection is impaired by the corrugated, cryptic surface, and nodularity of lymphatic tissue which decreases the sensitivity of physical examination while the vascularity and fluorodeoxyglucose (FDG) avidity of the lymphoid tissue obscure small tumors by computerized tomography (CT) and positron emission tomography (PET). We have invented a library of ultra pH sensitive (UPS) nanoprobes, covalently conjugated to indocyanine green (ICG) that respond to acidic tumor microenvironment, with a concomitant sharp change in their fluorescence state from OFF to ON. One such nanoprobe, ONM-100, has been developed and studied in a Phase 1 and ongoing FDA approved Phase 2 clinical trial. it has been shown to be well tolerated with no serious adverse events, compatible with surgical endoscopes, and able to detect a variety of cancers including HNSCC in real time. Based on these data we hypothesize that ONM-100 used as an adjunct to SOC panendoscopy can improve detection of UPC. To test our hypothesis, we will (1) Compare the sensitivity and specificity of activatable probe ONM-100 for cancer detection to always ON probes for tumors in Waldeyer's ring; (2) Detect HPV-mediated HNSCC in patients after systemic administration of ONM-100 comparing fluorescence to true-positive cancers; (3) Detect UPC in patients after systemic administration of ONM-100. Successful execution of this project will provide precise excision of UPC and avoidance of intense adjuvant therapy for UPC patients significantly improving care and outcomes for these patients who suffer greatly from less oncologically effective imprecise overtreatment.

A pH Responsive Transistor-like Nanoprobe for Sensitive Detection of Unknown Primary Cancers of the Head and Neck Project Narrative This application uses activatable fluorescence nanoprobe ONM-100 to evaluate the sensitivity and specificity of detecting unknown primary cancer in head and neck cancer patients after intravenous injection and imaging during surgery.