Efficacy and Safety Study With Visonac Photodynamic Therapy (PDT)

Double blinded, prospective, randomized, stratified, placebo-controlled, multi-center study in patients with moderate to severe acne vulgaris. Patients with facial severity grades 3 to 4 on the Investigator's Global Assessment (IGA) scale will be included. Each patient will be classified according to age in the two age groups 9 to 12 years and 13 to 35 years and randomized to either Visonac or vehicle cream within each age group. All patients will receive 4 treatments 2 weeks apart (at week 0, 2 ,4 and 6 week). Efficacy evaluation will be done after each treatment and at 12 weeks after the first treatment. Safety evaluations will be performed at each treatment visit and at 12 weeks after the first treatment.

Photographs of patients will be taken before and after treatment at first and last treatment visit, and at 12 weeks after first treatment.

Blood samples will be drawn at 3 visits; pre-treatment visit, one week after first treatment and at one week after last treatment visit.