Improved, Faster Lesion Clearance With M-PDT vs Isotretinoin in Acne Vulgaris

Treatment with modified 5-aminolevulinic acid photodynamic therapy (M-PDT) yielded improved lesion clearance, a faster onset of improvement, and a similar overall effective rate at 6 months compared with isotretinoin (ISO) therapy in adult patients with moderate to severe acne vulgaris, according to study results published in the Journal of the American Academy of Dermatology.

Researchers conducted a prospective, randomized, multicenter study to evaluate the efficacy and adverse events (AEs) associated with M-PDT and ISO in patients with acne vulgaris at dermatology outpatient clinics in 3 hospitals in China from September 2019 to September 2021. Eligible patients were 18 to 40 years of age, had a clinical diagnosis of moderate to severe acne, Pillsbury grade III and IV, and agreed to take contraceptive measures during treatment. Patient follow-up was scheduled at 6 months post-therapy.

Patients were randomly assigned in a 1:1 ratio to the intervention group (treatment with M-PDT) or control group (treatment with ISO). In the M-PDT group, up to 5 sessions were conducted at 1-week intervals, following manual comedone extraction. The ISO group received oral ISO at a dose of 0.5 mg/kg once daily for 6 months, with a total dose of 90 mg/kg.

The overall effective rate (number of patients with a clearance rate of 75% or higher divided by the total number of patients) was the primary efficacy outcome.

A total of 152 patients were allocated and included in the intent-to-treat (ITT) population. The M-PDT group included 77 patients (mean [SD] age, 26.66 [4.05] years; 47 men), while the ISO group included 75 (mean [SD] age 25.80 [3.92] years; 48 men). The per-protocol (PP) cohort comprised the 101 patients who completed the study.

Overall effective rates in the M-PDT group were significantly higher than those in the ISO group at 1 month (ITT, 66.23% vs 13.33%, respectively, P <.001; PP, 67.74% vs 10.26%, respectively, P <.001). At 1 month, the efficacy was greater in the ISO group vs the M-PDT group (ITT, 85.33% vs 70.13%, respectively, P <.05; PP, 97.44% vs 75.81%, respectively, P <.01).

M-PDT and ISO demonstrated comparable efficacy overall, with no significant difference observed between the groups at 2, 4, and 6 months posttherapy.

The time to achieve 50% lesion improvement was significantly less in the M-PDT group than in the ISO group (median of 1 week vs 8 weeks, respectively; P <.001). Patients’ Acne Quality of Life score was improved in the 2 groups after treatment and maintained during the 6-month follow-up period, with a similar recurrence rate between groups (M-PDT, 24.14% vs ISO, 38.46%; P =.13).

Most AEs in the M-PDT group were skin-limited and occurred in 99% of patients. AEs included mild erythema, edema, exudation, or dryness, all of which were successfully alleviated by moisturization and cooling. The M-PDT group had no systemic symptoms, and 71% of patients in the ISO group had documented systemic side effects such as liver dysfunction, gastrointestinal discomfort, increased lipid profile, depression, and menstrual disorders.

Study limitations include a potentially reduced statistical power due to small sample sizes, a high drop-out rate in the isotretinoin group, the relatively short follow-up period of 6 months, and inclusion of few nodulocystic lesions. Additionally, comedone extraction was performed only in the M-PDT group as a pretreatment before illumination.

“M-PDT offers a more rapid onset of improvement, comparable overall efficacy, good tolerability, and comparable durability of response compared with ISO,” the researchers concluded. They added, “Further larger studies with longer follow-up time are needed.”