Painless PDT using 10% aminolevulinate gel and red light: A pilot clinical trial of short-contact protocols to reduce discomfort during illumination.

Abstract

Background: Traditional red light photodynamic therapy for actinic keratoses (AK) causes significant pain during illumination.

Objective: To evaluate new short-incubation red light PDT regimens for their pain and efficacy characteristics.

Methods: Patients (n = 30) with facial AK were treated with 10% ALA gel (no occlusion) and red light (635 nm), after randomization as follows [incubation time, illumination time (fluence)]: Group A [10 min, 20 min (74 J/cm²)]; Group B [20 min, 10 min (37 J/cm²)]; Group C [1 hour, 10 min (37 J/cm²)]. Pain and AK lesion counts were recorded during two PDT treatments spaced 8 weeks apart. Final lesion counts were at 3-6 months.

Results: At both treatment visits, Group A and B patients experienced negligible pain that was statistically less than that of Group C patients. AK clearance after two PDT treatments was robust and similar amongst the three treatment groups (76% for Group A, 74% for Group B, and 82% for Group C). Using a non-inferiority margin of 15%, lesion reduction in Group A was statistically non-inferior to Group C after one PDT treatment.

Limitations: Efficacy rates of the new short incubation protocols (done without occlusion) were not compared directly with the long (3-hour) FDA-approved protocol that is done with occlusion.

Conclusion: Short-contact red light PDT regimens are essentially painless and appear to provide very good AK lesion clearance.

Clinical trial registration: NCT06027619 (date of trial registration: 31 August, 2023).