A Study to Evaluate Efficacy and Safety of Light Dose in Subjects With PWB Treated With Hemoporfin PDT

This is a multi-center, randomized, double-blind, vehicle-controlled, and sequential group Phase 2 study. Eligible subjects aged 18 to 75 years old with PWB will receive Hemoporfin PDT or vehicle PDT in cycles at fixed drug dose (5 mg/kg) and different light fluences. This study will be conducted in two sequential stages, each contains the same schedule, which includes Screening Period, Treatment Period apart; subsequent treatment is based on efficacy evaluation, and End of Study.