Is a 4 J/cm² PpIX-Weighted Simulated Daylight (SDL-PDT) Dose Still Efficient for Photodynamic Therapy of Actinic Keratosis?

• Main Authors: Mathilde Fronville (Author), Muriel Creusot (Author), Serge R. Mordon (Author)
• Format: Book
• Published: MDPI AG, 2023-10-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 10.3390/ph16101454; 1424-8247
• Keywords: actinic keratosis; photodynamic therapy; protoporphyrin IX; artificial daylight; indoor daylight; simulated daylight; Medicine; R; Pharmacy and materia medica; RS1-441
• Source: Pharmaceuticals, Vol 16, Iss 10, p 1454 (2023)

<b>Background:</b> Several solutions are now proposed to provide indoor illumination with so-called <b>artificial</b> white <b>light</b> or simulated <b>daylight</b> (SDL-<b>PDT</b>), resulting in an effective treatment for actinic keratosis (AK). However, the optimal PpIX-weighted light dose is still debated. Integrating the effective irradiance over the irradiation time yields the effective light dose, which is also known as the protoporphyrin IX-weighted light dose and is a key parameter for the efficacy of the treatment. <b>Objectives:</b> The paper aims to report the clinical outcomes of SDL-PDT when using the PpIX-weighted light dose of 4 J/cm², in patients treated for AK lesions of the scalp or the face at our medical dermatology center (ClinicalTrials.gov NCT052036). <b>Methods:</b> A total of 30 patients (16 males, 14 females), with a mean age of 71.0 ± 10.2, with phototype 1 (16 patients) and phototype 2 (14 patients) with grade I-II AK were treated with a drug light interval (DLI) of 10 min and a light exposure of 35 min (Dermaris, Surgiris, Croix, France), corresponding to a PpIX-weighted light dose of 4 J/cm². The primary endpoint was the cure rate of patients at six months post-treatment. Secondary endpoints included scores of pain, erythema, crusts, and discomfort during or/and post the treatment. <b>Results:</b> In total, 762 AK were treated. Six months following treatment, the cure rate of the patients was 77%. The median pain score was less than 1 out of 10 for most of the patients. Erythema was observed in all patients and lasted 3 days (±1.5 day). Crusts were seen in 28 patients. Discomfort was reported as mild or less in more than 97% of patients. <b>Conclusions:</b> The shortening of the PpIX-weighted light dose to 4 J/cm², corresponding to an illumination duration of 35 min with the Dermaris, does not modify the efficacy of the SDL-PDT. This observation is in agreement with recent published data demonstrating that the light dose can be reduced. Furthermore, this clinical study confirmed that SDL-PDT is an effective and nearly painless treatment with minimal side effects for patients with AK lesions of the scalp.