A Double Blinded, Prospective, Randomized, Vehicle Controlled Multi-center Study of Photodynamic Therapy With Visonac® Cream in Patients With Acne Vulgaris

Inclusion Criteria: * Female and male patients, from 12-35 years of age with severe facial acne vulgaris (IGA score 4 on IGA scale) * Signed and verified informed consent form and photo consent form. For subjects under age of 18, an assent form in conjunction with an informed consent form, signed and verified by parent/guardian. * Female patients who are surgically sterile, pre-menstrual, postmenopausal, abstinent, or willing to use an adequate means of contraception including birth control pills, or barrier methods and spermicide for at least 14 days prior to T1. Patients using birth control pills must have used the same product and dose for at least 3 months and must agree to stay with the same product and dose for an additional 3 months. * Fitzpatrick skin type I through VI, * Patients with 25 to 75 inflammatory lesions (papules, pustules, and nodules) on the face. * Patients with 20 to 100 non-inflammatory lesions (open and closed comedones) on the face. Exclusion Criteria: * Patients with acne conglobata, acne fulminans, secondary acne (chloracne, drug-induced acne, etc.) * Patients with more than 3 nodules on the face. * Patient is the investigator or any sub investigator, research assistant, pharmacist, study coordinator, other staff or relative thereof directly involved in the conduct of the study. * Patients unlikely to comply with the protocol, e.g. mental condition rendering the patient unable to understand the nature, scope, and possible consequences of the clinical study, uncooperative attitude or unlikelihood of completing the study (e.g. drug or alcohol abuse). * Female patients with childbearing potential (i.e. ovulation, pre-menopausal, not surgically sterilized) and sexually active, not willing to use a medically accepted contraceptive regimen (as described under inclusion criteria) while on treatment. * Pregnancy. * Nursing. * Participation in other clinical studies either currently or within the last 30 days. * Patients with porphyria. * Patients with cutaneous photosensitivity. * Known allergy to MAL, to a similar PDT compound, or to excipients of the cream * Patients using testosterone, any other systemic hormonal treatment or hormonal contraceptives solely for control of acne. * Patients who have received topical treatments for their facial acne within the last 14 days (e.g steroids, retinoids, glycolic acid, benzoyl peroxide, anti inflammatory agents, antibiotics). Medicated cleansers may be used during the washout period and stopped before the treatment. * Patients who have received oral antibiotics for treatment of their acne within the last month. * Patients who have received oral isotretinoin within the last 6 months. * Patient who have received facial procedures like dermabrasion, chemical or laser peels within the last 1 month. * Patients using testosterone, any systemic hormonal treatment for other reasons than acne treatment and has not been on the same product and dose for at least 3 months * Patients with moderate, severe or very severe facial acne scarring according to scarring scale described in section 10.4.3. * Patients with a beard that might interfere with study assessments. * Patients with melanoma or dysplastic nevi in the treatment area. * Exposure to ultraviolet radiation (UVB phototherapy, sun tanning salons) within the last 30 days * Exposure to PDT within 12 weeks before T1.