The main purpose of this vehicle-controlled study is to determine the efficacy and safety of a solution of Actikerall® (containing 5-fluorouracil 0.5% and salicylic acid 10.0%) in the field-directed treatment of grade I-II actinic keratosis, when it is applied to the affected area once daily for 12 weeks.

A secondary objective of this study is to evaluate the efficacy of Actikerall® solution on subclinical actinic keratosis lesions in a subset of patients.

Inclusion Criteria:

• Adult male or non-pregnant, non-lactating (in the last 3 months) female aged between 18 and 85 years (both inclusive). Women of childbearing potential will follow specific study requirements.
• Patients with at least 4 but not more than 10 clinically confirmed actinic keratoses lesions grade I or II (according to Olsen EA et al. 1991) within a field of cancerization of 25 cm² in the face/forehead or bald scalp.
• Patients with skin type I to IV (according to Fitzpatrick Skin Types)
• Patients free of any significant physical abnormalities (e.g., tattoos, dermatoses) in the potential treatment area that may interfere with area examination or final evaluation.
• Patients in good health condition or free of medical conditions that may interfere with the study results as confirmed by a physical examination, medical history and laboratory analysis.
• Patients who accept to refrain from sunbathing, intense UV-light exposure and the solarium during the study duration.
• Patients willing to stop using moisturizers and topical treatments with anti-aging products, vitamins A, C, and/or E containing ointments and gels and green tea preparations in the treatment area.
• Patients able (physical ability or supportive person) to apply the study preparations correctly and to follow the study procedure and restrictions.
• Patients with at least 3 subclinical lesions in the 25 cm² test area (field) clearly separated from each other and the actinic keratoses lesions (additional inclusion criteria for the patients participating on the sub-clinical lesions sub-study).

Exclusion Criteria:

• Subjects that have received treatment for actinic keratoses within the treatment area in the 3 months previous to Visit 1 (screening).
• Subjects that have received prohibited pharmacological or non-pharmacological treatments for any indication other than actinic keratoses within the treatment area before randomization (Visit 2).
• Subjects that have received prohibited systemic treatments for any indication before randomization (Visit 2).
• Subjects taking phenytoin, methotrexate or sulfonylurea.
• Subjects with dermatological diseases in the treatment area or surrounding area that may be exacerbated by the study treatment or may interfere the study assessments (e.g. psoriasis, eczema).
• Subjects that have currently malignant or benign tumors of the skin within the treatment area (e.g., malignant melanoma, basal cell carcinoma, squamous cell carcinoma).
• Subjects that suffer from any kind of photodermatoses.
• Subjects that have evidence of clinically significant unstable medical conditions.
• Subjects with known hypersensitivity to any of the trial drugs (5-fluorouracil, salicylic acid), to ingredients of the trial formulation, or to drugs of similar chemical classes
• Subjects with allergy against dimethylsulfoxide, ethanol, ethyl acetate, pyroxyline, poly(butyl)methacrylate, and/or methylmethacrylate.
• Subjects with dihydropyrimidine dehydrogenase deficiency (DPD deficiency).
• Subjects that are currently participating or have participated within the 8 weeks prior to Visit 1 in another clinical trial.
• Patients with known drug or alcohol abuse as assessed by the investigator within the 2 years prior to Visit 1.
• Subject is institutionalized because of legal or regulatory order.