The purpose of this study is to evaluate the safety and dose-response of 2 concentrations of A-101 versus a vehicle control in the treatment of seborrheic keratosis.

The main objective of this study is to evaluate the dose-response relationship of 2 concentrations of A-101 Solution and its matching A-101 Solution Vehicle when applied to seborrheic Keratosis (SK) target lesions on the face. A further objective is to evaluate the safety and efficacy of 2 concentrations of A-101 Solution and its matching A-101 Solution Vehicle when applied topically up to 2 times to SK target lesions on the face.

Inclusion Criteria:

1. Subject is at least 18 years of age

2. Subject has a Fitzpatrick skin type of 1-4

3. Subject has a clinical diagnosis of stable clinically typical seborrheic keratosis

4. Subject has 1 appropriate seborrheic keratosis target lesion, as defined below (Section 5.4), on the face:

   • Have a clinically typical appearance
   • Be treatment naïve
   • Have a Physician's Lesion Assessment (PLA) of ≥2 (Section 6.1.2)
   • Have a longest axis that is ≥7mm and ≤15mm (Section 5.4)
   • Have a longest dimension perpendicular to the longest axis that is ≥7mm and ≤15mm (Section 5.4)
   • Have a thickness that is ≤2mm
   • Be a discrete lesion
   • Be, when centered in the area outlined by the provided 3cm diameter circular template, the only seborrheic keratosis lesion present
   • Not be on the eyelids
   • Not be within 5mm of the orbital rim
   • Not be covered with hair which, in the investigator's opinion, would interfere with the study medication application or the study evaluations (NB: the study medication may bleach hair)
   • Not be in an intertriginous fold
   • Not be pedunculated.

5. If the subject is a woman of childbearing potential, she has a negative urine pregnancy test and agrees to use an approved effective method of birth control (Section 8) for the duration of the study

6. Subject is non-pregnant and non-lactating

7. Subject is in good general health and free of any known disease state or physical condition which, in the investigator's opinion, might impair evaluation of the target lesion or which exposes the subject to an unacceptable risk by study participation

8. Subject is willing and able to follow all study instructions and to attend all study visits

9. Subject is able to comprehend and willing to sign an Informed Consent Form (ICF).

Exclusion Criteria:

1. Subject has clinically atypical and/or rapidly growing seborrheic keratosis lesions

2. Subject has presence of multiple eruptive seborrheic keratosis lesions (Sign of Leser-Trelat)

3. Subject has a current systemic malignancy

4. Subject has a history of keloid formation or hypertrophic scarring

5. Subject has used any of the following systemic therapies within the specified period prior to Visit 1:

   • Retinoids; 180 days
   • Glucocortico-steroids; 28 days
   • Anti-metabolites (e.g., methotrexate); 28 days

6. Subject has used any of the following topical therapies within the specified period prior to Visit 1 on, or in a proximity to the target lesion, which in the investigator's opinion, interferes with the application of the study medication or the study assessments:

   • LASER, light (e.g., intense pulsed light (IPL), photo-dynamic therapy(PDT)) or other energy based therapy; 180 days
   • Retinoids; 28 days
   • Liquid nitrogen, electrodesiccation, curettage, imiquimod, 5-fluorouracil, or ingenol mebutate; 60 days
   • Glucocortico-steroids or antibiotics; 14 days

7. Subject currently has or has had any of the following within the specified period prior to Visit 1 on, or in a proximity to the target lesion, which in the investigator's opinion, interferes with the application of the study medication or the study assessments :

   • A cutaneous malignancy; 180 days
   • Experienced a sunburn; 28 days
   • A pre-malignancy (e.g., actinic keratosis); currently
   • Body art (e.g., tattoos, piercing, etc.); currently
   • Excessive tan; currently

8. Subject has a history of sensitivity to any of the ingredients in the study medications

9. Subject has any current skin disease (e.g., psoriasis, atopic dermatitis, eczema, sun damage, etc.), or condition (e.g., sunburn, excessive hair, open wounds) which, in the investigator's opinion, might put the subject at undue risk by study participation or interfere with the study conduct or evaluations

10. Subject has participated in an investigational drug trial in which administration of an investigational study medication occurred within 30 days prior to Visit 1.

Treatment-emergent adverse events (TEAEs) had a start date on or after the date of Visit 2 (study day 1) and treatment-emergent serious adverse events (TESAEs) had a start date on or after the date of Visit 1 (Screening). Collection continued through the patients last visit or the end of the study, visit 8 (Day 106.)

An adverse event (AE) was any untoward medical occurrence in a patient or clinical investigation subject administered a study medication(s) and that did not necessarily have a causal relationship with the study medication.

Safety summaries by study medication group will include listings by study medication of adverse events incidences within each MedDRA System Organ Class, and changes from pre-application values in vital signs.