Adverse events should be reported. Reporting forms and information can be found at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. Adverse events should also be reported to Biofrontera Pharma GmbH on +49 214 876 32 66 or Ameluz@biofrontera.com
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Photodynamic Therapy

Photodynamic therapy (PDT) is a procedure used in dermatology for the lesion- or field-directed treatment of various indications.1-4 The mechanism of action of PDT is based on the selective destruction of neoplastic cells through the application of a photosensitising substance in combination with light and oxygen. This procedure can take various forms, such as conventional red light PDT or daylight PDT, which differ, among other things, in the light source used.
The spectrum of approved indications varies depending on the drug used and the light treatment selected, and includes:5-7

  • Actinic keratosis (AK)5-7and field cancerisation5
  • Appropriate forms of basal cell carcinoma5,6

Basics of PDT

PDT requires three components: a photosensitiser, light of an appropriate wavelength, and oxygen (see Fig. 1).8,9

A photosensitiser is a molecule that can transfer energy to oxygen molecules when excited by light. Often, the molecule protoporphyrin IX (PpIX) provides the photosensitising properties.9 In dermatology, PDT drugs contain a PpIX metabolic precursor, such as 5-ALA, which allows for targeted PpIX synthesis in diseased tissue.9,10 Critical to the efficacy of PDT is the use of a light source that matches the absorption spectrum of the photosensitiser.8,9 PpIX has a total of 5 absorption maxima, at 405 nm (blue), 505 nm (blue), 540 nm (green), 575 nm (yellow), and 635 nm (red).

Figure 1: The three key components of photodynamic therapy

In the context of daylight PDT, all PpIX absorption maxima are stimulated by daylight.10,11 In contrast, only red light is used in conventional PDT, which can penetrate particularly deeply into the skin and is therefore particularly well suited as a light source for PDT.

In this process, the oxygen molecules serve as acceptors for the energy from the excited PpIX and thus become cytotoxic reactive oxygen species (ROS). ROS oxidize cell membranes and other cellular components, leading to necrosis or apoptosis of target cells, such as neoplastic cells.8,9

After the treatment, the wound healing process begins: The destroyed cells are replaced by healthy skin cells. Erythema, oedema and crusting may occur in the first few days. These are signs of wound healing that usually subside within a few days.5,12

The benefits of PDT

PDT offers the benefits:

  • High efficacy in lesion- and field-directed treatment3
  • Short treatment duration of a few hours1 leading to high adherence13
  • Minimally invasive therapy option
  • Local skin reactions usually resolve within 1 to 2 weeks
  • Visible improvement in the appearance of the skin after treatment9,14
  • PDT is recognised as a treatment by private health insurers as well as NHS England’s national tariff payment system

PDT with Ameluz® (78 mg/g 5-aminolaevulinic acid gel)

PDT with Ameluz® containing the active substance 5-aminolevulinic acid (5-ALA) is approved for the following indications5:

Daylight PDT:

Actinic keratosis and field cancerisation
on the face and scalp*

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Conventional PDT:

Actinic keratosis and field cancerisation*
Appropriate forms of basal cell carcinoma**

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In Phase III studies, Ameluz®  showed high efficacy in terms of complete lesion and patient-related clearance rates, both in conventional and daylight PDT. In addition to high clearance rates, Ameluz®  also achieved an excellent cosmetic result.5,10

In a network meta-analysis, conventional PDT with Ameluz®  in combination with a narrow-spectrum red light source proved to be a highly effective therapy option for the treatment of mild to moderate AK on the face and scalp.15

* Actinic keratosis of mild to moderate severity (grade 1 to 2 according to Olsen) and field cancerisation in adults
** Superficial and/or nodular basal cell carcinoma in adults not suitable for surgical treatment due to possible disease-related morbidity and/or poor cosmetic results

References

  1. Wong T et al., British Association of Dermatologists and British Photodermatology Group guidelines for topical photodynamic therapy.Br J Dermatol 2019;180;730-739
  2. European Dermatology Forum guidelines on topical photodynamic therapy – Part 1 (established indications) und Part 2 (emerging indications). www.onlinelibrary.wiley.com/doi/10.1111/jdv.16017 (last accessed November 2021) and  onlinelibrary.wiley.com/doi/full/10.1111/jdv.16044 (last accessed November 2021).
  3. Morton CA et al. JEADV 2019;33:2225-2238.
  4. Morton CA et al. JEADV 2020;34:17-29.
  5. Ameluz® Summary of Product Characteristics.
  6. Metvix® Summary of Product Characteristics.
  7. Alacare® Summary of Product Characteristics.
  8. Agostinis P et al. CA Cancer J Clin 2011;61:250-281.
  9. Ericson MB et al. Ther Clin Risk Manag 2008;4:1-9.
  10. Reinhold U et al. Br J Dermatol 2016;175:696-705.
  11. Peng Q et al. Cancer 1997;79:2282-2308.
  12. Velnar T et al. J Int Med Res 2009;37:1528-1542.
  13. Foley P et al. The Journal of dermatological treatment 2016;27:538-545.
  14. Nguyen M et al. Clin Cosmet Investig Dermatol 2019;12:427-435.
  15. Vegter S, Tolley K. PLoS One 2014;9:e96829.

UKBF-2022-006b-V01, Date of preparation: June 2022