Study of Reformulated Levulan Kerastick Plus PDT for Actinic Keratosis on Upper Extremities

• Reformulated Levulan Kerastick containing aminolevulinic acid hydrochloride (ALA HCl), 20% (Drug): Solution for topical use
• Vehicle (Other): Solution for topical use
• Blue Light Photodynamic Therapy Illuminator device, BLU-U® model 4170E. (Device): BLU-U® blue light PDT illuminator

Primary outcomes

• Complete Clearance Rate (CCR) i.e., proportion of patients achieving complete clearance of all AK lesions in the Treatment Area) [Week 12]: Complete clearance is defined as clearance of all AK lesions in the Treatment Area after PDT 1 or PDT 2, if re-treated; lesions should no longer be palpable nor visible to be declared as "cleared"

Secondary outcomes

• Actinic Keratosis Clearance rate (AKCR) [Week 4, 8 ,12, 20, and 24]: AKCR for each patient is calculated as 100 x \[1- (number of target AK lesions present at that particular visit/ number of target AK lesions present at Baseline)\]. Target lesions are those AK lesions that were identified at baseline and treated at baseline
• Proportion of patients achieving clearance of target lesions in the Treatment Area [Weeks 4, 8, 12, 20, and 24]: Target lesions are those AK lesions that were identified at baseline and treated at baseline.
• Complete Clearance Rate (CCR) i.e., proportion of patients achieving complete clearance of all AK lesions in the Treatment Area [Weeks 4, 8, 20, and 24]
• Partial Clearance Rate (PCR); i.e., Proportion of patients achieving partial clearance of AK lesions) [Weeks 4, 8, 12, 20, and 24]: Partial clearance is defined as clearance of at least 75% of all AK lesions in the Treatment Area; lesions should no longer be palpable nor visible to be declared as "cleared".
• Percent change in total AK lesion count from Baseline [Weeks 4, 8, 12, 20, and 24]
• Percent change in total AK lesion area from Baseline [Weeks 8, 12, and 24]
• Investigator Assessment of Cosmetic Response [Weeks 12, 20, and 24]: The overall cosmetic response to treatment will be assessed by a Blinded Investigator using a 4-point scale, selecting the score that best describes the patient's cosmetic outcome in actinic keratosis since treatment initiation: 1 = Excellent, 2 = Good, 3 = Fair, and 4 = Poor.
• Patient Assessment of Cosmetic Response [Weeks 12, 20, and 24]: The patient's overall cosmetic response to treatment will be measured by the patient on a 4-point scale, where 1 = Excellent, 2 = Good, 3 = Fair, and 4 = Poor
• Patient Satisfaction Score (PSS) at Weeks 12, 20, and 24. [Weeks 12, 20, and 24]: The patient's overall satisfaction with the study treatment will be assessed using a 4-point patient-reported scale, where 0 = Not satisfied at all, 1 = Slightly satisfied, 2 = Moderately satisfied, and 3 = Very satisfied.
• Recurrence Rate at Week 24. Measured as proportion of patients presenting with at least one recurrent lesion during the follow-up period, after having achieved complete clearance at Week 12. [Week 24]: Measured as proportion of patients presenting with at least one recurrent lesion during the follow-up period, after having achieved complete clearance at Week 12.

Sex: All, ages: 18 Years to 85 Years

Inclusion Criteria:

1. Patient is a male or non-pregnant female aged 18-85 years.
2. Patient must have 4-8 mild to moderate actinic keratosis (AK) lesions (Olsen grade 1 or 2) in a single treatment area on their Index arm, each measuring up to 1 cm in diameter and spaced at least 1 cm apart.

   \[The treatment area should be approximately 25 cm², located on the extensor surface of only one of the upper extremities that is selected as the Index arm\]
3. Patients must be in good general health, avoid sunbathing or tanning devices, and maintain a consistent skincare routine throughout the study.
4. Patient is willing to stop using all topical products within the Treatment Area within 8 hours of a scheduled clinic visit with an efficacy evaluation.
5. Women of childbearing potential must use highly effective contraception; men with such partners must use barrier methods unless surgically sterile.

Exclusion Criteria:

1. Presence of Olsen grade 3 AK, untreated or suspicious skin cancers, or significant skin abnormalities (e.g., psoriasis, eczema) in the treatment area.
2. Active herpes simplex infection or history of ≥2 outbreaks in the treatment area within the past year.
3. History of cutaneous photosensitization, porphyria, photodermatosis, or hypersensitivity to porphyrins.
4. Positive human immunodeficiency virus (HIV) test result, hepatitis B surface (HBS) antigen, or hepatitis C virus (HCV) test result
5. Immunosuppressed status (e.g., HIV, organ transplant) or known coagulation defects.
6. Use of specific topical therapies (e.g., retinoids, steroids, cryotherapy, PDT, chemical peels) on the treatment area within 2 days to 8 weeks prior to randomization.
7. Recent use of certain systemic therapies (e.g., corticosteroids, immune-modulators, retinoids, cytotoxic drugs) within 6 weeks to 6 months prior to randomization.
8. Recent use of hypericin or other phototoxic/photoallergic medications (e.g., tetracyclines, psoralenes, St. John's wort) within 8 weeks of randomization.
9. Clinically significant or unstable illnesses, or history of alcohol/drug abuse in the past year.
10. Pregnancy/lactation, recent or current participation in another clinical study, or any other condition deemed unsuitable by the Investigator.