The primary objective of this study is to evaluate the safety and effectiveness of 2 concentrations of A-101 compared to Vehicle for the treatment of 4 seborrheic keratosis (SK) Target Lesions on the trunk, extremities and face.

The primary objective of this study is to evaluate the safety and effectiveness of 2 concentrations of A-101 compared to Vehicle for the treatment of 4 seborrheic keratosis (SK) Target Lesions on the trunk, extremities and face.

The secondary objectives of this study include duration of response of A-101. During the study, the investigator will identify 4 eligible SK Target Lesions on each subject on the trunk, extremities and face. For each subject, at least 1 SK Target Lesion must be on the face and at least 1 Target Lesion must be on the trunk or extremities. The Target Lesions will be treated at a maximum of two treatment visits.

Inclusion Criteria:

1. Subject is able to comprehend and is willing to sign an informed consent for participation in this study.

2. Male or female ≥ 18 years old.

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

4. Subject has 4 appropriate seborrheic keratosis Target Lesions on the trunk, extremities and face, with at least 1 Target Lesion on the face and at least 1 Target Lesion on the trunk or extremities. The 4 identified Target Lesions must meet the requirements as defined below:

   1. Have a clinically typical appearance
   2. Have a Physician's Lesion Assessment of ≥ 2
   3. Length that is ≥ 5mm and ≤ 15mm
   4. Width that is ≥ 5mm and ≤ 15 mm
   5. Thickness that is ≤ 2mm
   6. Be a discrete lesion
   7. Be the only SK lesion present when centered in the area outlined by the provided circular template
   8. Not be covered with hair which, the in the investigator's opinion, would interfere with the study medication treatment or the study evaluations
   9. Not be in the intertriginous fold
   10. Not be on the eyelids
   11. Not be within 5mm of the orbital rim
   12. Not be pedunculated

5. Subject chemistry and complete blood count results are within normal limits. If any of the laboratory values are outside normal range, the treating investigator must assess the value/s as NOT clinically significant and document this in the subject's medical chart in order for the subject to be eligible for randomization.

6. Woman of childbearing potential must have a negative urine pregnancy test within 14 days of the first application of study drug and agree to use an active method of birth control for the duration of the study.

7. Subject is non-pregnant and non-lactating.

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

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

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 current systemic malignancy.

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

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

5. Subject has used any of the following topical therapies within the specified period prior to Visit 1 on, or in a proximity to any Target Lesion, that in the investigator's opinion interferes with the study medication treatment or the study assessments:

   • LASER, light or other energy based therapy (e.g., intense pulsed light, photo-dynamic therapy; 180 days
   • Liquid nitrogen, electrodesiccation, curettage, imiquimod, 5-Fluorouracil, or ingenol mebutate; 60 days
   • Hydrogen peroxide: 90 days
   • Retinoids; 28 days
   • Microdermabrasion or superficial chemical peels; 14 days
   • Corticosteroids or antibiotics; 14 days

6. Subject would require the use of any topical treatment (e.g. moisturizers, sunscreen) to any of the Target Lesions 12 hours prior to any study visit.

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 any Target Lesion that, in the investigator's opinion, interferes with the study medication treatment or the study assessments:

   • Cutaneous malignancy; 180 days
   • Sunburn; currently
   • Pre-malignancy (e.g. actinic keratosis); currently
   • Body art (e.g. tattoos, piercing, etc.); currently
   • Excessive tan; currently. The use of self-tanning lotions/sprays are prohibited.

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), or condition (e.g., sunburn, excessive hair, open wounds) that, in the opinion of the investigator, might put the subject at undue risk by study participation or interfere with the study conduct or evaluations.

10. Participation in another therapeutic investigational drug trial in which administration of an investigational study medication occurred within 30 days prior to Visit 1.