Oropharyngeal Carcinoma (OPC)

The goal of this study is to understand whether CRB-701, a targeted form of chemotherapy called an anti-body drug conjugate, will work as a treatment for oropharyngeal (throat, tonsil) cancer. In patients who have already received platinum based chemotherapy or immunotherapy (using a check-point inhibitor) It will also learn about the safety of the drug and measure quality of life. The main questions it asks are: * What proportion of participants respond to CRB-701 measured using scans (CT or MRI) * What medical problems do participants experience when taking CRB-701. Researchers will compare CRB-701 with standard of care medicines (drugs that are normally used this disease). Participants will: * Attend clinic every three weeks to receive infusions of CRB-701 or standard of care medicines until the cancer cannot be measured or is not controlled by the treatment they are receiving. * Have a CT or MRI every 6 weeks to measure the effect on their cancer * Complete questionnaires to assess their health status.

This study focuses on the longitudinal monitoring of HPV infection in patients with head and neck cancers, particularly oropharyngeal carcinoma (OPC), using a new electrochemical detection method. This method has already been successfully developed and validated for cervical cancer. The aim of the project is to monitor the dynamics of HPV viral load before the start of treatment and during conservative radiation therapy or concurrent chemoradiation therapy. HPV will be analyzed from oral swabs, oral cavity washings, and plasma as part of a small prospective study. The results of the new method will be correlated with standard techniques, particularly qPCR. Longitudinal monitoring may contribute to the individualization and potential de-escalation of treatment in selected patients.