Benzoporphyrin (verteporfin) photodynamic therapy for choroidal neovascularization in age-related macular degeneration

Abstract

Purpose: To review and discuss the available treatments for choroidal neovascularization (CNV) due to age-related macular degeneration (AMD) emphasizing to photodynamic therapy (PDT). Methods: Published papers from 1974 until 1999 related to AMD, its available treatments and PDT were reviewed. Results: The most used effective treatment for CNV is laser photocoagulation which does not have a major impact on the blindness due to AMD. Alternative techniques of prevention and treatment are under investigation including surgery, pharmacological antiangiogenic treatment and prevention with photocoagulation. PDT using verteporfin demonstrated effectiveness in closing CNV membranes in an experimental model. A clinical trial showed that a single course treatment could stabilize the area and extent of leakage from subfoveal CNV with classic component in the majority of patients for up to 3 months (Phase I/II). A 12-month data for quaterly treatments was recently reported and showed that vision stabilization, meaning vision improvement, no change, or loss of < 3 lines, occurred in 61.4% of the verteporfin-treated eyes and verteporfin-treated eyes are more likely to avoid a six-line or greater loss (85%) compared to placebo (76%). Another clinical trial (Phase III B) is under way to analyze the role of PDT in the occult type of CNV. Conclusion: Treatment for this devastating condition remains a challenge. These clinical studies have shown an early closure of the CNV following PDT with exciting results in terms of visual acuity, although on a long-term basis these results are yet to be proven. Photodynamic therapy is one of the most promising new technologies to treat CNV.