Safety and Efficacy of Escalating Doses of Ingenol Mebutate Once Daily for Two or Three Consecutive Days When Used on Full Face, Full Balding Scalp or Approximately 250 cm2 on the Chest in Subjects With Actinic Keratosis

Inclusion Criteria:

- Subjects must be competent to understand the nature of the trial and provide informed
consent

- Part 1: Subjects with 5 to 20 clinically typical, visible and discrete AKs on the
face Part 2: Subjects with 5 to 20 clinically typical, visible and discrete AKs on
either the face, the balding scalp (the balding part of the scalp should be at least
25 cm2) or a contiguous area of approximately 250 cm2 on the chest

- Subject at least 18 years of age

- Female subjects must be of either:

1. Non-childbearing potential, i.e. post-menopausal or have a confirmed clinical
history of sterility (e.g. the subject is without a uterus) or,

2. Childbearing potential, provided there is a confirmed negative urine pregnancy
test prior to trial treatment, to rule out pregnancy

- Female subjects of childbearing potential1 must be willing to use effective
contraception at trial entry and until completion

Exclusion Criteria:

- Location of the treatment area (full face, full balding scalp or chest)

- within 5 cm of an incompletely healed wound,

- within 10 cm of a suspected basal cell carcinoma (BCC) or squamous cell
carcinoma (SCC

- Prior treatment with ingenol mebutate gel within the treatment area

- Lesions in the treatment areas that have:

- atypical clinical appearance (e.g., hypertrophic, hyperkeratotic or cutaneous
horns) and/or,

- recalcitrant disease (e.g., did not respond to cryotherapy on two previous
occasions

- History or evidence of skin conditions other than the trial indication that would
interfere with the evaluation of the trial medication (e.g., eczema, unstable
psoriasis, xeroderma pigmentosum)

- Use of cosmetic or therapeutic products and procedures which could interfere with the
assessments of the treatment areas.

- Clinical diagnosis/history or evidence of any medical condition that would expose a
subject to an undue risk of a significant AE or interfere with assessments of safety
and efficacy during the course of the trial, as determined by the investigator's
clinical judgment

- Any abnormal laboratory tests that are medically significant and would impact the
safety of the subjects or the interpretation of the trial results, as determined by
the investigator's judgment

- Anticipated need for hospitalisation or out-patient surgery during the first 15 days
after the first trial medication application. Note that cosmetic/therapeutic
procedures are not excluded if they fall outside of the criteria detailed in
Prohibited Therapies or Medications

- Known sensitivity or allergy to any of the ingredients in ingenol mebutate gel

- Presence of acute sunburn within the treatment areas

- Current enrolment or participation in an investigational clinical trial within 30
days of entry into this trial.

- Subjects previously assigned to treatment in Part 1 or rand

- Female subjects who are breastfeeding.

- In the opinion of the investigator, the subject is unlikely to comply with the
Clinical Study Protocol (e.g. alcoholism, drug dependency or psychotic state)