Stemming vision loss could improve the quality of life for many diabetics, allowing them to keep driving cars or taking part in other everyday activities.

Analysts say the drug, which is awaiting federal marketing approval, could be a blockbuster for Lilly, with sales over $1 billion a year.

The potential market for Arxxant is vast, given that a third or more of diabetics have vision deterioration, called diabetic retinopathy.

No drug currently treats the disorder. The vision loss is treated now with laser surgery, typically when the problem is advanced. Lilly officials say Arxxant could be used earlier to slow the deterioration before the vision loss becomes severe.

41 Percent Reduction

The Indianapolis drug maker revealed the latest findings Sunday before a highly interested audience: doctors and other diabetes practitioners gathered in Washington, DC, for the annual scientific meeting of the American Diabetes Association.

Lilly's presentation played up the fact that two late-phase tests of Arxxant showed it reduced the risk of vision loss by 41 percent, compared to a placebo or sugar pill, among patients with serious eye problems caused by their diabetes.

The studies show Arxxant could be "an advance in diabetes that nobody else has been able to achieve," said Dr. Louis Vignati, medical director for the Arxxant product team at Lilly.

Stemming vision loss could improve the quality of life for many diabetics, allowing them to keep driving cars or taking part in other everyday activities, he said.

Another Tool

"Laser treatments are not fun. I would so rather pop a pill than go do that again," said Martha Cattell, a 28-year-old diabetic woman from Fort Wayne.

After noticing black spots in her vision a few years ago, Cattell had laser treatments that were so painful she said she screamed through the first one, despite Valium and numbing drops. She said she'd welcome a drug-based treatment.

The two Lilly-sponsored studies, which enrolled 813 patients with diabetic eye disease, tracked them for three years. Over that time, 6.1 percent of patients who took Arxxant daily suffered moderate vision loss, compared to 10.2 percent of patients who took a placebo.

Vision loss was defined as a three-line drop on the eye chart.

Lilly's drug isn't likely to help everyone, cautioned Dr. Vincent Keszei of the Keszei Vision Center on Indianapolis' Southside.

"It slows down vision loss. It does not get rid of diabetic retinopathy. It's not a cure-all," he said. "It's another thing we have in our bag of tools that we can use."

Inhibits an Enzyme

The studies backed up Arxxant's reputation for being safe. The drug didn't affect patients' blood-sugar levels or blood pressure, and fewer patients suffered "serious adverse events" while taking Arxxant than taking the sugar pill. Indigestion was the most frequent side effect linked to the drug.

Credit Suisse First Boston last year forecast Arxxant's peak sales at $1.1 billion. That doesn't include selling Arxxant to treat nerve pain associated with diabetes, an area where it proved ineffective in tests.

The Food and Drug Administration has agreed to speed up its normal one-year review time for Arxxant, since there are no approved treatments for diabetic eye disease. That shaves six months off the review process.

The drug works by inhibiting an enzyme in the body that helps enable the process that damages blood vessels in the eye. The eye suffers damage in two ways, only one of which Arxxant seems to help prevent, Vignati said.