Intervention: Imiquimod
Trial phase: Phase 3
ATC code: D06BB10
SMILES: CC(C)Cn1cnc2c(N)nc3ccccc3c21
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 187
Group description: Zyclara® (imiquimod) cream 2.5% was applied once daily approximately 1 to 2 hours before bedtime to the skin of the treatment area (either full face [excluding the ears] or balding scalp) for two, 2-week treatment cycles separated by a 2-week no-treatment period. Participants applied test article for 14 consecutive days for each treatment cycle.
Eligibility criteria:
Inclusion Criteria:

Participant is a male or female, 18 years of age or older.
Participant has provided written informed consent.
Participant is willing and able to apply the test article as directed, comply with study instructions and commit to all follow-up visits for the duration of the study.
Participant has a clinical diagnosis of AK with at least 5 and no more than 20 clinically typical, visible or palpable AK lesions, each at least 4 millimeters (mm) in diameter, in an area greater than 25 cm^2 on the face (excluding ears) or balding scalp, but not both.
Participant is in good general health and free of any disease state or physical condition that might impair evaluation of AK lesions or which, in the investigator's opinion, exposes the participant to an unacceptable risk by study participation.
Females must be post-menopausal, surgically sterile or use an effective method of birth control, with a negative urine pregnancy test (UPT) at the Baseline visit.

Exclusion Criteria:

Participant is pregnant, lactating, or is planning to become pregnant during the study.
Participant has hyperkeratotic, hypertrophic or atypical AKs (for example, AK greater than [>] 1 cm^2 in size) in the treatment area.
Participant is currently enrolled in an investigational drug or device study.
Participant plans to be exposed to artificial tanning devices or excessive sunlight during the trial.
Participant is immunosuppressed (for example; human immunodeficiency virus [HIV], systemic malignancy, graft vs. host disease, etc.).
Participant has experienced an unsuccessful outcome from previous imiquimod therapy (an unsuccessful outcome is defined as after a reasonable therapeutic trial with no compliance issues and the topical drug do not work).
Participant has used an investigational drug or investigational device within 30 days prior to the Baseline visit.
Participant has had dermatologic procedures or surgeries such as: laser resurfacing, PUVA (Psoralen + ultraviolet A) therapy, UVB therapy, chemical peels or dermabrasion on the face or balding scalp within 6 months prior to the Baseline visit.
Participant has cryodestruction or chemodestruction, curettage, photodynamic therapy, surgical excision or other treatments for AK on the designated treatment area (face or scalp) within 1 month prior to the Baseline visit.
Participant has used oral corticosteroid therapy, interferon, cytotoxic drugs, immunomodulators, immunosuppressive therapies or retinoids within 1 month prior to the Baseline visit.
Participant has used topical medications; corticosteroids, alpha hydroxyl acids (for example; glycolic acid, lactic acid etc. >5%), beta hydroxy acid (salicylic acid >2%), urea >5%, 5-fluorouracil, diclofenac, imiquimod, ingenol mebutate or prescription retinoids (for example; tazarotene, adapalene, tretinoin) to the face or balding scalp within one month prior to the Baseline visit.
Participant has used topical creams, lotions or gels of any kind to the selected treatment area within one day prior to the Baseline visit.
Participant has lesions suspicious for skin cancer (skin cancer not ruled out by biopsy) or untreated skin cancers within the selected treatment area (face or scalp).
Participant has a history of sensitivity to any of the ingredients in the test articles.
Participant has any skin pathology or condition (for example; facial/scalp psoriasis, atopic dermatitis, acne, rosacea, etc.) that, in the investigator's opinion, could interfere with the evaluation of the test article, worsen due to the treatment or requires the use of interfering topical, systemic or surgical therapy.
Participant has any condition which, in the investigator's opinion, would make it unsafe or precludes the participant's ability to fully participate in this research study.
Participant is known to be noncompliant or is unlikely to comply with the requirements of the study protocol (for example; due to alcoholism, drug dependency, mental incapacity) in the opinion of the investigator.