Patients completed two phases of screening termed Initial Screening and Final Screening. Initial Screening assessed the EpCAM status of the patient's SCCHN prior to final screening procedures taking place. Patients had to have a biopsy of their advanced disease that had been appropriately collected for verification of EpCAM-positive SCCHN by immunohistochemical methods. If EpCAM-positive SCCHN was confirmed, the patient could enter Final Screening to determine full eligibility for participation in the study. At the beginning of Final Screening, all patients had to have received at least one anti-cancer treatment regimen for advanced disease. Patients who had successfully completed both Initial and Final Screening had a Principal Target Tumour and up to five additional Target Tumours designated for treatment prior to Day 1 dosing. Only one target tumour per week was to be injected. The Investigator was to treat the principal target tumour until clinically relevant tumour control of the principal target tumour was achieved, at which point other target tumours could be chosen and injected once per week at the same dose level of Proxinium.