Photodynamic therapy (PDT) is a highly effective, non-invasive, irradiation-free light therapy to treat AK, performed by a healthcare provider. In principle, it uses light and a photosensitizing (i.e. making something sensitive to light) gel or solution. A preferred photosensitizing substance is aminolevulinic acid (ALA), a naturally occurring precursor of protoporphyrin IX (PpIX), the photoactive (i.e. activated by light) substance. Once inside the cell, ALA is converted into PpIX by a series of enzymatic reactions. PpIX is activated by light in the presence of oxygen, resulting in the elimination of AK cells. Aminolevulinic acid is primarily absorbed by premalignant cells, leaving healthy skin cells mostly intact.
In general, PDT can be performed with different light sources. Although the human eye is not able to see the different colors in daylight, seemingly “white” visible light contains a broad range of different wavelengths, with spectra of red, yellow, green and blue light. The red light of the BF-RhodoLED® lamp activates the photosensitizer at a wavelength of 635 nm, targeting actinic keratoses in the entire epidermis.
Once your AK diagnosis has been confirmed by a doctor, and you and your doctor have decided on PDT with Ameluz® (aminolevulinic acid hydrochloride) gel, 10% your skin will be prepared for the treatment. Ameluz® should only be administered by a healthcare provider.
Ameluz® has been approved for lesion-directed and field-directed photodynamic therapy of actinic keratoses of mild-to-moderate severity on the face and scalp using the BF-RhodoLED® lamp. It is for topical use only.
Step 1: Lesion preparation and application of Ameluz®
Initially the skin is degreased with alcohol to cleanse the treatment area. After removing scabs of more moderate actinic lesions, Ameluz® is applied to the affected skin. Special care should be taken to avoid bleeding during lesion preparation in patients with inherited or acquired coagulation disorders. Direct contact of Ameluz® with eyes and the mucous membranes should be avoided.
Ameluz® should be applied at a thickness of 1 mm. No more than 2 grams (one tube) of Ameluz® should be applied at any one time. Larger skin areas may be treated separately or in two office visits.
To avoid a premature reaction, the treatment area is covered with a light occlusive dressing, a process called occlusion.
Step 2: Illumination with the BF-RhodoLED®
After an incubation period of 3 hours the occlusion and any remaining gel is removed, followed by illumination with the BF-RhodoLED® lamp for 10 minutes. Eye exposure to the BF-RhodoLED® light must be prevented. Patients, healthcare providers and any person present during the illumination period must wear protective eyewear before operating the lamp. Avoid staring directly into the light source.
After the treatment, patients should avoid sunlight, prolonged or intense light (e.g., tanning beds, sun lamps) on lesions and surrounding skin treated with Ameluz® for approximately 48 hours following treatment, whether exposed to illumination or not.
Local skin reactions at the application site were observed in about 99.5% of patients. The sensation of pain and other frequently observed adverse reactions include reddening of the skin at the application site, burning, irritation, swelling, itching, scaling, crust formation, hardening and blistering.
Most adverse reactions occurred during illumination or shortly afterwards, were generally of mild or moderate intensity and lasted for 1 to 4 days in most cases. In some cases, however, they persisted for 1 to 2 weeks or even longer. Severe pain/burning occurred in up to 30% of patients. Cooling of the treatment area during and after PDT usually reduces the symptoms.
The healing process usually takes a few days. However, some signs may remain for up to a couple of weeks. Once the crusts are gone, the skin appears smooth.
The final results of the treatment will be examined by your doctor three months after your first PDT, to determine if all AKs have been eliminated. If any AK remains, a second PDT should follow. It was demonstrated in clinical trials that about six out of ten patients treated with Ameluz® and the BF-RhodoLED® and did not require a second PDT. About 9 out of 10 patients who received one or two treatments with Ameluz were completely cleared of their AKs.