This Phase III study is designed to evaluate the efficacy and safety of KX01 Ointment in adult participants when applied to an area of skin containing more than 1, clinically typical Actinic Keratosis (AK) lesions on the face or scalp.

This study is a double-blinded, multicenter, activity, and safety study of KX01 Ointment administered topically to the face or scalp of participants with actinic keratosis. The study consists of Screening, Treatment, Follow-up, and Recurrence Follow-up Periods. Eligible participants received 5 consecutive days of topical treatment, to be applied at the study site. Activity (lesion counts) and safety evaluations is performed.

Inclusion Criteria:

1. Japanese Males and females ≥20 years old

2. A treatment area on the face or scalp that:

   1. is a contiguous area measured 25 cm2
   2. contains more than 1 clinically typical, visible, and discrete AK lesions

3. Subjects who, in the judgment of the Investigator or Sub-investigator, are in good general health based on:

   1. medical history
   2. physical examination (PE) findings
   3. vital signs
   4. clinical chemistry, hematology, and urinalysis results

4. Females must be postmenopausal (>45 years of age with at least 12 months of amenorrhea), surgically sterile (by hysterectomy, bilateral oophorectomy, or tubal ligation); or, women with childbearing potential must use highly effective contraception for at least 30 days or 1 menstrual cycle, whichever is longer, prior to study treatment and must agree to continue to use highly effective contraception for at least 30 days following their last dose of study treatment. Highly effective contraception includes oral hormonal contraceptives, hormonal contraceptive implant, injection or patch, intrauterine device, or complete abstinence from sexual intercourse.

5. Sexually active males who have not had a vasectomy and whose partner is reproductively capable must agree to use barrier contraception from Screening until 90 days after their last dose of study treatment.

6. All subjects must agree not to donate sperm or eggs or attempt conception from Screening until 90 days following their last dose of study treatment.

7. Females of childbearing potential must have a negative serum pregnancy test at Screening and a negative urine pregnancy test on Day 1 prior to randomization.

8. Willing to avoid excessive sunlight or ultraviolet (UV) light exposure, including the use of tanning beds, to the face or scalp

Exclusion Criteria:

1. Clinically atypical and / or rapidly changing AK lesions on the treatment area, e.g., hypertrophic, hyperkeratotic, recalcitrant disease (had cryosurgery on two previous occasions) and / or cutaneous horn

2. Location of the treatment area is:

   • On any location other than the face or scalp
   • Within 5 cm of an incompletely healed wound
   • Within 5 cm of a suspected basal cell carcinoma (BCC) or SCC

3. Been previously treated with KX01 Ointment

4. Anticipated need for in-patient hospitalization or in-patient surgery from Day 1 to Day 57

5. Treatment with 5-fluorouracil (5-FU), imiquimod, ingenol mebutate, diclofenac, photodynamic therapy, or other treatments for AK within the treatment area or within 2 cm of the treatment area, within 8 weeks prior to the Screening visit

6. Use of the following therapies and / or medications within 2 weeks prior to the Screening visit:

   • Cosmetic or therapeutic procedures (e.g., use of liquid nitrogen, surgical excision, curettage, dermabrasion, medium or greater depth chemical peel, laser resurfacing) within the treatment area or within 2 cm of the selected treatment area
   • Acid-containing therapeutic products (e.g., salicylic acid or fruit acids, such as alpha- and beta-hydroxyl acids and glycolic acids), topical retinoids, or light chemical peels within the treatment area or within 2 cm of the selected treatment area
   • Topical salves (non-medicated / non-irritant lotion and cream are acceptable) or topical steroids within the treatment area or within 2 cm of the selected treatment area; artificial tanners within the treatment area or within 5 cm of the selected treatment area

7. Use of the following therapies and / or medications within 4 weeks prior to the Screening visit:

   • Treatment with immunomodulators (e.g., azathioprine), cytotoxic drugs (e.g., cyclophosphamide, vinblastine, chlorambucil, methotrexate), or interferons / interferon inducers