This pilot clinical study will evaluate the safety, tolerability, and effectiveness of a novel photodynamic therapy (PDT) for moderate-to-severe acne vulgaris. PDT combines a topical photosensitizing gel with red light to treat acne lesions. The gel to be used in this study, called RLP068/Cl (a zinc phthalocyanine compound), has demonstrated antimicrobial, anti-inflammatory, and sebosuppressive effects in laboratory studies.

A total of 10 patients with moderate-to-severe acne on the face will be enrolled. RLP068/Cl 0.3% gel will be applied topically for 30 minutes under occlusion, followed by 8 minutes of red LED light exposure. Treatments will be performed twice weekly, with the total number of sessions individualized based on clinical response.

Acne severity will be assessed using the Global Acne Grading System (GAGS). Pain levels will be recorded after each session using a visual scale, and patient satisfaction will be evaluated at the end of the treatment cycle.

The goal of the study is to determine whether RLP068/Cl-PDT is a safe, well-tolerated, and effective non-antibiotic treatment option for patients with moderate-to-severe acne vulgaris who may not respond to or tolerate conventional therapies.

Inclusion Criteria:

• Male or female participants aged ≥16 years.
• Diagnosis of moderate-to-severe acne vulgaris (comedonal, papulopustular, or cystic), with facial lesions symmetrically distributed.
• Washout period of at least 6 months from prior oral acne treatments.
• Washout period of at least 2 months from prior topical acne treatments.
• Ability to understand the study procedures and provide written informed consent.

Exclusion Criteria:

• Use of systemic or topical photosensitizing medications.
• Known photosensitivity disorders.
• Pregnancy or breastfeeding.
• Participation in another interventional clinical study within the past 3 months.
• Any dermatological condition of the face that may interfere with treatment assessment (e.g., eczema, rosacea).
• Any serious uncontrolled medical condition deemed by the investigator to pose a risk to the participant or interfere with study results.