Metvix PDT Versus Vehicle PDT With Aktilite CL128 Lamp in Patients With Actinic Keratosis on the Face and Scalp

Actinic keratoses are pre-malignant skin lesions, which may develop to squamous cell carcinomas (SCC). They are usually small, thin, erythematous, de-squamating lesions on light exposed atrophic skin and the lesions are often multiple.

Photodynamic therapy (PDT) is the selective destruction of abnormal cells through light activation of a photosensitiser in the presence of oxygen. These cells accumulate more photosensitiser than normal cells. The photosensitiser generates reactive oxygen species upon illumination.

For skin diseases, such as actinic keratosis (AK), there has been an increasing interest in using topically applied precursors of the photoactive porphyrins (PAP). The most commonly used precursors have been 5-aminolevulinic acid (ALA) and its derivatives. The present test drug contains methyl aminolevulinate, which penetrates the lesions well and shows high lesion selectivity.

Different light sources (i.e. CureLight, Aktilite CL16 and Aktilite CL128) had been used for the activation of PAP, which absorbs light in the range of 400-700 nanometer (nm). The present study used the Aktilite CL 128 lamp. Aktilite 128 was based on LED technology and emits a narrow red light spectrum with an average wavelength of 630 (+/-5) nm. This study was similar to two other studies performed, on which the U.S. approval of Metvixia cream was based except for the light source used. This study was one of two studies performed to document the safety and efficacy of the Aktilite CL 128 lamp when used in combination with Metvixia cream.

Previous studies have shown that the risks attributed to Metvixia PDT are few and related mainly to transient pain and local erythema during and shortly after treatment. These reactions are part of the expected local phototoxicity reaction. PDT offers an advantage to other treatment modalities for actinic keratosis, being a non-invasive treatment available on an outpatient basis. Several separate lesions can be treated simultaneously and the same lesion(s) can be treated repeatedly with success. There are no known systemic toxicity or interaction with other medication. The treatment is also lesion selective, leaving the surrounding tissue intact and functional, also allowing excellent cosmetic results after treatment.

Primary Outcome Measures

1. Participant Complete Response Rate (CRR)
   Participant complete response rate was defined as the percentage of participants with complete response. Complete response was defined as the complete disappearance of the lesion determined by clinical assessment (visual inspection and palpation) by an investigator.

Secondary Outcome Measures

1. Lesion Complete Response Rate
   Lesion complete response rate was defined as the percentage of pre-existing and treated lesions at baseline that were assessed as clear (complete disappearance of the lesion, visually and by palpation) after treatment. Percentage of lesions reported by location.
2. Number of Participants With at Least One Treatment Site Adverse Events
   An AE was any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and which does not necessarily had a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory value), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. Number of participants with at least one treatment site adverse events were reported.