Specifically, the study focused on patients with macular edema because of
central retinal vein occlusion, or blockage of retinal veins. Macular edema is a
condition in which the macula, or central part of the retina, swells because
fluid leaks or builds up.

In the 114-person study, the drug prompted vision improvements. The study
showed that 56.1 percent of patients receiving the injections on a monthly basis
gained at least 15 letters in vision tests. That compares with only 12.3 percent
of patients receiving placebo injections.

An additional late-stage study is ongoing.

Meanwhile, the company reported positive results from a midstage study
focusing on VEGF Trap-Eye’s use as a treatment for diabetic macular edema. The
condition is a disease of the retina that affects individuals with diabetes and
can lead to blindness.

Regeneron and Bayer are also developing the drug candidate as a treatment for
wet age-related macular degeneration, which results in vision loss as new blood
vessels grow beneath the retina and leak blood and fluid, damaging the retina
and distorting vision. The condition, which can progress to blindness, usually
affects older adults. The “dry” form of the condition is the most common type of
age-related macular degeneration, with the “wet” form considered the more
advanced version of the disease. There are up to 200,000 new cases for the “wet”
form of the condition each year in the U.S. Wet AMD is the leading cause of
blindness for people over the age of 65 in the U.S. and Europe.

The positive result in the macular edema indication triggers a $10 million
milestone payment for Regeneron from Bayer, in addition to a second $10 million
milestone Regeneron received earlier in the month for the wet AMD data.

The companies have said they plan to request European and U.S. regulatory
approval in the first half of 2011 for the “wet” form of the condition.