The clinical trial aims to test the long term safety of a new drug for acne vulgaris. The trial is performed to answer this question "Is it safe to apply the IMP daily for up to 52 weeks?". The trial aims to accurately measure the safety and the effects of the new treatment (N-Acetyl-GED-0507-34-LEVO gel 5%) and to achieve this, patients will be review the drug containing the active ingredient.

Participants will:

• Take drug every day for up to 52 weeks
• Visit the site once every 4 weeks for checkups and tests (where applicable) for the first 3 months of treatment, then visit the site every 13 weeks approximately for checkups and tests (where applicable).
• Record on a diary the daily/weekly applications of the study drug at home, and record any adverse events

Inclusion Criteria:

• Informed consent obtained* * Written informed consent, before any study-related procedure, personally signed and dated by the patient if the patient is ≥ 18 years old or signed and dated by the parents or the legal guardian(s) if the patient is ≥ 9 to < 18 years old. An additional informed assent form must be signed by patient if ≥ 9 to < 18 years old to confirm his willingness to participate in the study. If the patient becomes 18 years of age during the study, the patient must provide written informed consent at that time to continue study participation.

• Sex and age: Male and female patients aged ≥ 9 and < 50 years. Patients who turn 50 during the pivotal study can roll over to the LT study.

• Diagnosis at screening and baseline visits:

• a. Patients affected by facial acne vulgaris with an Investigator's Global Assessment (IGA) score: =1 or 2 for pivotal-naïve* patients not included in pivotal 12 Week treatment studies ≥ 0 for patients completing the 12-Week treatment period according to protocol in the pivotal Phase 3 trials (NAC-GED-0507-ACN-01-23-A and NAC-GED-0507-ACN-01-23-B)

• b. Patients affected by truncal acne (optional criteria) on areas of the trunk (shoulders, upper back and upper anterior chest) accessible for patient's self- application of study medication with a Physician Global Assessment (PGA) severity grade: =1 or 2 for pivotal-naïve* patients not included in the pivotal 12Week treatment studies ≥ 0 and < 4 for patients completing the 12-Week treatment period according to protocol in the pivotal Phase 3 trials (NAC-GED-0507-ACN-01-23-A and NAC-GED-0507-ACN-01-23-B)

  • Pivotal-naïve: Patients not rolling over from NAC-GED-0507-ACN-01-23-A and NAC-GED-0507-ACN-01-23-B. If the pivotal-naïve patient is ≥ 9 and ≤ 14 years old and declined participation to pivotal Phase 3 study, a 12-week period should run before inclusion in the present study. During the 12-week period the patients will be allowed to follow their doctor's instructions regarding treatment of acne.

• Full comprehension Patients and their parents/legal guardian(s) (for < 18 years old patients) can comprehend the whole nature and purpose of the study, including possible risks and side effects, and are able to cooperate with the Investigator and to comply with the requirements of the entire study.

• Contraception and fertility: Women of childbearing potential must be using an effective contraception method during the entire duration of the study. Effective contraception methods are those considered at least "acceptable" according to CTFG Recommendations. A prior stable treatment period is required for the following reliable methods of contraception:

  1. Hormonal oral, implantable, transdermal, or injectable contraceptives must be stable for at least 6 months before the screening visit
  2. A non-hormonal intrauterine device (IUD) must be started at least 2 months before the screening visit.

Exclusion Criteria:

• Acne:

  • Patients with generalized or localized acne forms other than acne vulgaris, e.g., acne conglobata, acne fulminans, acne rosacea, secondary acne (chloracne, drug-induced acne, etc), nodule-cystic acne
  • Patients with acne requiring systemic treatment.

• Beard and facial/body hair, tattoos:

  • Patients with a beard or who intend to grow a beard and/or to perform a facial tattoo during the study
  • Patients with facial hair or facial tattoos that could interfere with study assessments in the investigator's opinion
  • For patients with truncal acne: body hair, tattoos (or who intend to perform them) on the shoulders, upper back or upper anterior chest accessible to self-application of study medication by the patient (evaluable area) that may interfere with the study assessments in the investigator's opinion.

• Skin diseases: Patients with other active skin diseases (e.g., urticaria, atopic dermatitis, sunburn, seborrheic dermatitis, perioral dermatitis, rosacea, skin malignancies) or active skin infections in the facial or truncal region (bacterial, fungal, or viral) or any other facial or truncal disease or condition that might interfere with the evaluation of acne or place the patient at unacceptable risk.

• Allergy: Known or suspected hypersensitivity to any active or inactive ingredient in the study medication. Patients with a history of an allergic reaction or significant sensitivity to the formulations' ingredients.

• Topical therapies: Patients who are currently using, plan to use during the study, or discontinued less than 4 weeks before study baseline the use of prescribed or over-the-counter topical therapies for the treatment of acne, including but not limited to: corticosteroids, antibiotics, azelaic acid, benzoyl peroxide, salicylates, α-hydroxy/glycolic acid, any other topical cosmetic therapy for acne and retinoids on the face/trunk.

• Topical skin care products and procedures: Patients who are currently using, plan to use during the study, or discontinued less than 4 weeks before study baseline the use of products for facial/truncal application containing glycolic or other acids, masks, washes or soaps containing benzoyl peroxide or salicylic acid, non-mild cleansers or moisturizers containing retinol, salicylic or alpha- or beta-hydroxy acids, facial/truncal procedures such as chemical peel, laser treatment, photodynamic therapy, acne surgery, cryodestruction or chemodestruction, x-ray therapy, intralesional steroids, dermabrasion;

• Phototherapy: Patients who are currently using, plan to use during the study, or discontinued less than 4 weeks before study baseline phototherapy for the treatment of acne, including but not limited to: UV-A, UV-B, heliotherapy. Patients who have the need or plan to be exposed to artificial tanning devices or excessive sunlight during the study.

• Systemic therapies: Patients who are currently using, plan to use during the study, or discontinued less than 12 weeks before study baseline the use of systemic therapies for the treatment of acne, including but not limited to: antibiotics, isotretinoin. Other systemic therapy that could affect the patient's acne (i.e., anabolics, lithium, EGRF inhibitors, iodides, systemic corticosteroids - except inhaled corticosteroids or intrathecal corticosteroids - or other immunosuppressants), in the opinion of the investigator.

• Known systemic diseases that can lead to acneiform eruptions:

  1. Increased androgen production.

     1. Adrenal origin: e.g., Cushing's disease, 21-hydroxylase deficiency;
     2. Ovarian origin: e.g., polycystic ovarian syndrome, ovarian hyperthecosis

  2. Cryptococcosis disseminated

  3. Dimorphic fungal infections

  4. Behçet's disease

  5. Systemic lupus erythematosus (SLE).

• Investigative studies: Participation in the evaluation of any other investigational product or device within 24 weeks before study baseline.

• Diseases: Patients with underlying uncontrolled or unstable conditions (including but not limited to metabolic, hematologic, renal, hepatic, pulmonary, neurologic, endocrine, cardiac, infectious or gastrointestinal), which, in the Investigator's opinion, could significantly compromise the patient's safety and/or place the patient at an unacceptable risk. Any condition that in the investigator's opinion would make it unsafe for the patient to participate in the study.

• Alcohol and other substance abuse: History of alcohol or other substance abuse within one year before screening.

• Communication: Patient(s) and parents/legal guardian(s) (if applicable) unable to communicate or cooperate with the investigator due to e.g., language problems, impaired cerebral function, impaired mental conditions.

• Reliability: Patients who may be unreliable for the study including patients who are unable to return for the scheduled visits.

• Pregnancy*: Pregnant or breastfeeding women or women of childbearing potential who are planning to become pregnant during the study. *For all female patients of childbearing potential, pregnancy test result must be negative at screening.