AMD is the leading cause of irreversible, severe loss of vision in people 50 years and older in the developed world and remains an area of unmet medical need. The neovascular or wet form of the disease represents about 10 percent of the overall disease prevalence, but is responsible for 90 percent of the severe vision loss. In wet AMD, abnormal blood vessels grow under the central retina and cause a progressive loss of central vision, interfering with driving, reading and other everyday tasks. As the population ages, almost 1 million people over the age of 55 years in the United States are expected to develop AMD in the next five years, making it a major public health issue in an increasing population of older persons.
The paper in the New England Journal of Medicine details two clinical trials that were held at 117 sites in the Unites States, Canada, Europe, Israel, Australia and South America. Patients were eligible for inclusion if they were 50 years of age or older and had subfoveal choroidal neovascularization caused by AMD and a range of best corrected visual acuity of 20/40 to 20/320 in the study eye and of 20/8000 or better in the other eye. Of the 1,208 patients randomly assigned to treatment in the two studies, (297 patients were assigned to receive 0.3 mg of pegaptanib; 305 patients, 1.0 mg of pegaptanib; 302 patients, 3.0 mg of pegaptanib; and 304 patients, sham injections), 1,190 received at least one study treatment. Treatments were given by injection into the eye.