Verteporfin

Verteporfin, a benzoporphyrin derivative monoacid ring A, is a photosensitising drug for photodynamic therapy (PDT) activated by low-intensity, nonheat-generating light of 689nm wavelength. Activation generates cytotoxic oxygen free radicals. The specificity and uptake of verteporfin for target cells with a high expression of low density lipoprotein (LDL) receptors, such as tumour and neovascular endothelial cells, is enhanced by the use of a liposomal formulation and its rapid uptake by plasma LDL. Verteporfin therapy (at light doses < 150 J/cm(2)) selectively damages neovascular endothelial cells leading to thrombus formation and specific occlusion of choroidal neovascular vessels in subfoveal lesions in patients with age-related macular degeneration (AMD). Repeated applications of verteporfin therapy 6 mg/m(2) improved or maintained visual acuity in the majority of patients with some classic subfoveal choroidal neovascularisation (CNV) secondary to AMD at I year's follow-up in 2 large multicentre, placebo-controlled, double-blind trials. Furthermore, in a subgroup of these patients with predominantly classic CNV secondary to AMD, there was a significantly more marked visual acuity (VA) benefit with 67.3% of verteporfin-treated eyes experiencing less than a 15-letter loss of VA versus 39.3% with placebo treatment. Multiple applications of verteporfin therapy were well tolerated in patients with subfoveal CNV secondary to AMD. The most common adverse events were visual disturbances, injection site reactions, photosensitivity reactions and infusion-related back pain.