Dose-Response Profile of A-101 in Subjects With Seborrheic Keratosis

The main objective of this study is to evaluate the dose-response relationship of two
concentrations of A-101solution when applied to individual seborrheic keratosis (SK) lesions
(target lesions) compared with a matching A-101 Solution Vehicle.

Each subject will have 4 target lesions on the trunk/extremities.

A further objective is to evaluate the safety and efficacy of two concentrations of A-101
solution and its matching vehicle when applied to SK target lesions on the trunk/extremities.

Inclusion Criteria:

1. Subject is at least 18 years of age

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

3. Subject has 4 appropriate seborrheic keratosis target lesions, as defined below, on
the trunk/extremities:

- Have a clinically typical appearance

- Be treatment naïve

- Have a Physician Lesion Assessment (PLA) of ≥2

- Have a longest axis that is ≥7mm and ≤15mm

- Have a longest dimension perpendicular to the longest axis that is ≥7mm and ≤15mm

- 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 in an intertriginous fold

- Not be in an area where clothing, such as a bra, might cause physical irritation

- Not be pedunculated.

4. If the subject is a woman of childbearing potential, she has a negative urine
pregnancy test and agrees to use an active form of birth control for the duration of
the study

5. Subject is non-pregnant and non-lactating

6. 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 any target
lesion or which exposes the subject to an unacceptable risk by study participation

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

8. 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

- Glucocorticosteroids; 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, that 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; 90 days

- Liquid nitrogen, electrodesiccation, curettage, imiquimod, 5-fluorouracil, or
ingenol mebutate; 60 days

- Glucocorticosteroids or antibiotics; 14 days

- Moisturizers/emollients, sunscreens; 12 hours

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