Age-related macular degeneration is an eye disease with symptoms such as impaired or distorted central vision. It is one of the major causes of blindness in the elderly in developed countries. In the United States, about 15% of the people over 80 years of age were suffering from age-related macular degeneration in 2000. In Japan, in association with the aging society and the westernized food culture, patients of age-related macular degeneration have been increasing in recent years and it has become the fourth most common cause of acquired blindness.
Drusen, a waste product mainly comprising lipid, accumulates under the retinal pigment epithelium of the patients of age-related macular degeneration. Subsequently, in the case of exudative age-related macular degeneration subchoroidal neovascularization occurs, followed by reduced vision due to subretinal hemorrhage or retinal edema. Only vascular regression therapy (intravitreal administration of an anti-VEGF agent or photodynamic therapy) for established neovessels is currently available and effective for treating exudative age-related macular degeneration. Unfortunately, once neovascularization occurs, prognosis is generally poor even if such therapy is applied. For maintaining good vision it is important to suppress progression of the disease at the stage of the drusen formation, but no such therapy is currently available.
In the case of atrophic age-related macular degeneration, following the drusen accumulation chorioretinal atrophy gradually occurs without neovascularization, causing reduced vision. No effective therapy is currently available for atrophic age-related macular degeneration. Sometimes exudative age-related macular degeneration proceeds to atrophic age-related macular degeneration.
Accordingly, removing the drusen and/or suppressing the formation of the drusen is considered to be effective for treating and/or preventing age-related macular degeneration, but no agent having such effect exists.