A Multi-Center Study to Evaluate the Efficacy and Safety of KX2-391 Ointment 1% on AK on Face or Scalp

Inclusion Criteria 1. Males and females greater than or equal to (≥) 18 years old 2. A defined area on the face or scalp contains 4 to 8 clinically typical, visible, and discrete AK lesions 3. Participants who in the judgment of the Investigator, are in good general health 4. Females must be postmenopausal \[greater than (\>) 45 years of age with at least 12 months of amenorrhea\], surgically sterile (by hysterectomy, bilateral oophorectomy, or tubal ligation); or, if of childbearing potential, must be using 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 through 90 days after their last dose of study treatment. 6. All participants must agree not to donate sperm or eggs or attempt conception from Screening through 90 days following their last dose of study treatment 7. Willing to avoid excessive sun or UV exposure 8. Able to comprehend and are willing to sign the informed consent form (ICF). Exclusion Criteria 1. Clinically atypical and/or rapidly changing AK lesions on the treatment area 2. Location of the selected 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 squamous cell carcinoma (SCC) 3. Been previously treated with KX2-391 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 (eg, 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 (eg, 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 (eg, azathioprine), cytotoxic drugs (eg, cyclophosphamide, vinblastine, chlorambucil, methotrexate) or interferons/interferon inducers * Treatment with systemic medications that suppress the immune system (eg, cyclosporine, prednisone, methotrexate, alefacept, infliximab) 8. Use of systemic retinoids (eg, isotretinoin, acitretin, bexarotene) within 6 months prior to the Screening visit 9. A history of sensitivity and/or allergy to any of the ingredients in the study medication 10. A skin disease (eg, atopic dermatitis, psoriasis, eczema) or condition (eg, scarring, open wounds) that, in the opinion of the Investigator, might interfere with the study conduct or evaluations, or which exposes the participants to unacceptable risk by study participation 11. Other significant uncontrolled or unstable medical diseases or conditions that, in the opinion of the Investigator, would expose the participant to unacceptable risk by study participation 12. Females who are pregnant or nursing 13. Participated in an investigational drug trial during which an investigational study medication was administered within 30 days or 5 half-lives of the investigational product, whichever is longer, before dosing