London, UK; Brentwood, TN, US; 27 August 2008 - Protherics PLC (“Protherics” or the “Company”), the international biopharmaceutical company focused on critical care and cancer, today announces the initiation of a phase 2a proof-of-concept study of ProlarixTM, a targeted prodrug chemotherapy being developed for the treatment of primary liver cancer (hepatocellular carcinoma or “HCC”). This follows promising data from a phase 1 study of Prolarix, presented at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, USA on 2 June 2008.