Metvix® - Mechanism of action
Metvix® PDT is a topical treatment that consists of the Metvix cream combined with Photocure's proprietary light source, the Aktilite lamp. When the Metvix cream is applied to the lesions, the active ingredient accumulates in tumour tissue. Subsequent exposure to red light generates reactive oxygen, which destroys the malignant cells. See figure:
This procedure provides a precisely directed treatment that clears the lesions and leaves healthy skin unharmed. Metvix PDT is easy to perform and is offered by dermatologists on an outpatient basis.
Selectivity leads to the targeted destruction of tumour cells - healthy surrounding tissue is spared. Metvix selectivity is thought to result from differences in cellular uptake between cancerous and healthy cells.
1. Tumour cells accumulate PAPs (Photoactive porphyrins) and become sensitive to light.
2. Exposure to red light in the presence of oxygen generates cytotoxic singlet oxygen species
(ROS), which damage cellular membranes leading to tumour cell death.
3. Healthy surrounding tissue hardly accumulates PAPs due to the selectivity of Metvix for tumour
cells and therefore healthy tissue is not damaged.
Worldwide clinical trial programmes
The Metvix treatment is well-documented. Photocure has performed clinical trials at more than 100 clinics and hospitals across three continents to document the safety and efficacy of Metvix. The pivotal trials have been published in journals with high impact factors in dermatology, such as Journal of the American Academy of Dermatology, British Journal of Dermatology, Archives of Dermatology, Journal of Dermatologic Treatment, and Journal of the European Academy of Dermatology and Venerology.
In November 2005, Metvix was approved for Bowen's disease in Norway, Sweden, Denmark and Finland, in addition to 19 other European countries, through the European Mutual Recognition Procedure.
Treatment recommended by NICE, UK
Recently The National Instititute for Health and Clinical Excellence (NICE) issued a recommendation about photodynamic therapy for common skin cancer and pre-malign lesions. NICE recommendations are followed by the UK National Health System (NHS), and are also highly regarded by health authorities elsewhere in Europe and around the world.