PhotoCure ASA, a Norwegian company developing pharmaceuticals and medical devices based on proprietary photodynamic technologies, last week submitted a new drug application to the FDA for treatment of actinic keratosis, or precancerous skin lesions.

The treatment comprises topical application of its Metvix cream to the lesions for three hours, followed by illumination with red light.

PhotoCure CEO Vidar Hansson told BioWorld International that Metvix is a derivative of the amino acid aminolevulinic acid, with a substitution at the carboxyl terminal. It is selectively transported into precancerous cells, where it alters porphyrin biosynthesis. However, the mechanism underlying its therapeutic activity is not fully understood.

The Oslo-based company¿s NDA file includes data from 17 clinical studies involving 2,239 patients. In four Phase III trials involving 251 patients, the Metvix photodynamic therapy (PDT) combination was, the company said, ¿significantly more effective than placebo with respect to the proportion of patients showing complete lesion response and complete patient response at three months after treatment.¿

In a multicenter European study, one cycle of Metvix PDT treatment demonstrated an equivalent therapeutic outcome to two cycles of cryotherapy, the current standard treatment. Each achieved a response rate of 72 percent, Hansson said, although Metvix PDT resulted in a ¿much better¿ cosmetic outcome. In an Australian study, two cycles of Metvix PDT resulted in a 91 percent response rate, whereas one cycle of cryosurgery, the standard in that country, yielded a 67 percent response rate. Again, the cosmetic outcome associated with Metvix PDT was superior.

The American Academy of Dermatology describes actinic keratoses as ¿rough, red, scaly patches on the top layer of the skin, measuring anywhere from 1 millimeter to 1 inch in diameter.¿ They primarily are found on exposed areas of the body and are most likely to develop in fair-skinned individuals with a history of chronic exposure to sunlight.

¿People now understand that this is the precursor for squamous cell carcinoma, which kills large numbers of people every year,¿ Hansson said.

PhotoCure already obtained marketing authorization in Sweden for Metvix PDT in treatment of both actinic keratosis and basal cell carcinoma. It has scheduled a product launch on Oct. 18, and is seeking additional European authorizations under the 90-day mutual recognition procedure. The company is adopting a dual distribution strategy. ¿For the Nordic area we are building our own sales force,¿ Hansson said. The company plans to sign up one or more partners for other territories before the year¿s end.

PhotoCure was founded in 1993 to commercialize technologies developed at the Norwegian Radium Hospital. It listed on the Oslo Stock Exchange last year.