458 Evaluation of the Safety and Efficacy of Wst11mediated Vascular Targeted Photodynamic Therapy in Inoperable Cholangiocarcinoma

458 Evaluation of the Safety and Efficacy of Wst11mediated Vascular Targeted Photodynamic Therapy in Inoperable Cholangiocarcinoma Emmanuel Ben Soussan*, Jean Francois Lefebvre, Joseph Hardy, Sidney Houry alma clinic, Paris, France Introduction: Interest of PDT in cholangiocarcinoma remains controversial. The aims of this prospective phase II study was to evaluate a new photosensitive agent (WST11) which advantages are: 1) an innovative mechanism of action by vessels occlusion. 2) a short delay between intra-veinous infusion and its penetration of tumoral site (10 minutes) that allowed drug infusion in ERCP room 3) its short half-life (less than 2 hours) reducing the phototoxicity risks and limiting the duration of light protection measures. 4) its deep penetration in tumoral tissues (10-15 mm) without damage of normal tissues. Patients and Methods: From Nov 2009 to Dec 2010, seven pts (42-85 yrs, mean age 65.4) with inoperable cholangiocarcinoma (positive biopsies or cytology) have been treated with WST11. Patients were classified according to Bismuth classification: grade III (3 pts), grade II (3 pts) grade I (1 pts). Six patients were treated during ERCP and one during percutaneous procedure. Plastic stents or biliary drain were inserted after laser treatment in the same procedure. One single procedure with WST11 was performed during the 6 months follow-up for all patients, and 2 received subsequent chemotherapy. Preventive procedure of phototoxicity was made the first day after procedure. Results: No phototoxic or severe secondary effects occured in all patients during the 6 months follow-up, but all patients had an increased D Dimeres level. Two patients are still alive at 36 and 42 months without reccurence of disease in one. This 2 pts received post operative chemotherapy for grade I and III tumor. In four patients, stent ablation was done for stent obstruction. A complete healing of th stricture was found in 3 of the 4 pts. In one, stent have been definitively retriewed without tumoral reccurence at 42 months. Conclusion: This phase II study has shown the safety of WST 11 in non operable cholangiocarcinoma. Advantages of WST 11 are its short half-life and easy use during drainage procedure. Efficacy of this treatment must to be considered in phase III study in association with chemotherapy.