Study of WST11 in Patients With Localized Prostate Cancer

Inclusion Criteria: * Diagnosed with prostate cancer and eligible for active surveillance; * No prior treatment for prostate cancer; * Prostate Cancer Stage up to cT2b - N0/Nx - M0/Mx (rT2c and pT2c are acceptable); * Gleason score ≤ 3+3 For patients characterized with prostate mapping (transperineal template guided biopsy at 5mm intervals) a secondary pattern 4 is acceptable provided that it is not present in more than 3 cores from each side of the prostate and is no more than 3 mm cancer core length. * PSA \< 10 ng/mL; Exclusion Criteria: * Any condition or history of illness or surgery that, in the opinion of the investigator and/or the Sponsor, might confound the results of the study or pose additional risks to the patient. * Patients with a prior history of viral or alcoholic hepatitis, and other patients felt to be at risk for hepatotoxicity including concomitant use of potentially hepatotoxic medications or dietary supplements; * History of non compliance with medical therapy and medical recommendations or an unwillingness or inability to complete patient self-administered questionnaires; * Participation in a clinical study or receipt of an investigational treatment within the past 3 months; * A history of porphyria; * Patient with contra-indication to MRI (such as pace maker, metal prosthesis, etc.); * All patients whose current pre-operative cardiac evaluation does not show their fitness for a procedure requiring general anesthesia; * Patients with a history of inflammatory bowel disease or other factors which may increase the risk of fistula formation; * Men who have received any hormonal manipulation (excluding 5-alpha reductase inhibitors) or androgen supplements within the previous 6 months; * Men previously treated by radiation therapy (external therapy or brachytherapy) or chemotherapy or any therapy for prostate cancer; * Men who have received or are receiving chemotherapy for prostate carcinoma or other significant cancer; * Men who have undergone previous TURP (trans-urethral resection of the prostate); * Men who are currently receiving any medications having potential photosensitizing effects (e.g. tetracyclines, sulfonamides, phenothiazines, sulfonylurea hypoglycemic agents, thiazide diuretics and griseofulvin); * Men who are receiving anticoagulant drugs (e.g.: coumadin, warfarin) * Patient who stopped long term treatment of acetylsalicylic acid (aspirin) or other anti platelets agents less than 15 days before the procedure; * Patient suspected of Disseminated Intravascular Coagulation (DIC) as defined by the presence of three out of the five following criteria: platelets \<LLN, PT \>ULN,aPTT \>ULN, fibrinogen\<LLN, D-Dimer \>ULN; * A history of sun hypersensitivity or photosensitive dermatitis; * Renal disorders (blood creatinine \> 1.5 x ULN) or known post mictional residue \> 150cc; * Hepatic disorders (transaminases \> ULN, bilirubin \> ULN). In case of slight abnormalities, another exam should be performed. If the results are within normal ranges, then the patient can be included; * Hematological disorders (white cells \< 2500/mm3, neutrophils \< 1500/mm3, platelets \< 140.000/mm3, Hb \< 8 g/dl);