Drug Cos. Battle To Stop, Reverse Diabetic Nerve Damage
NEW YORK (AP)--The pain started as a cramp in Joe Oliva's toes and ankles. Within six months, he could no longer walk. The slightest pressure on his feet caused severe pain. He had to quit his job as a limousine driver.
"If I tried to sleep with a blanket, it felt like a lit cigarette on my toes," said Oliva, 36, of Deer Park, N.Y.
His ailment: Diabetic neuropathy, a nerve disorder that is one of the most common and troublesome complications of diabetes. Now, three major pharmaceutical companies are finalizing development of the first drugs to halt its progression.
Between one-third and one-half of the 16 million Americans with diabetes suffer from neuropathy. Millions of these patients are undiagnosed.
There's no cure. Neuropathy often causes prolonged numbness in the feet and hands, which gradually worsens, sometimes leading to foot ulcers, gangrene and amputation.
The three companies out front on neuropathy are Genentech Inc. (GNE), Pfizer Inc. (PFE) and Warner-Lambert Co. (WLA). They are in final stages of human testing for drugs to stop diabetic neuropathy from moving to its most severe stages. They may reverse damage already done.
The increase in diabetes research among large drug companies parallels a slow rise in public awareness of the sixth leading cause of death.
Like others, these three companies are attracted to the economics of treating diabetes.
With the aging population and increasing awareness, the number of diabetics seeking help is expected to steadily rise. Like other drugs for chronic diseases, patients would likely have to take a neuropathy medication for life.
In addition to diabetes, neuropathy is also caused by rheumatoid arthritis, cancer, leukemia, kidney disease, shingles and can be induced by certain drugs. As a result, the market for a neuropathy drug could be huge.
Even if only 10% of people with diabetic neuropathy took the drug, analysts say a company could reach $1 billion in annual sales.
"If they are successful, it has blockbuster potential," said Charles Engelberg, an analyst with AmeriCal Securities.
Pfizer and Warner-Lambert have other diabetes drugs in development or on the market. Pfizer is working on an inhaled form of insulin, replacing injections. Warner Lambert last year introduced Rezulin, a pill which is now one of the biggest selling diabetes drugs.
The neuropathy drugs offer hope for treating one of the more vexing complications of the disease, said Dr. Gerald Bernstein, director of the diabetes management program at Beth Israel Health System in New York and president of the American Diabetes Association.
"If we can regrow nerves that will make an extraordinary difference," Bernstein said.
Neuropathy involves the steady degeneration of the wiring around nerves that are essential for the brain to communicate with muscles, skin and organs.
In diabetics, the lack of insulin leads to production of an enzyme called aldose reductase, which creates a sugar that does the damage.
Up until now, doctors gave patients narcotics to mask the pain and anti-depression medications. Or they told patients to learn to live with it.
Previous research attempts failed because the drugs wouldn't absorb into tissues, or caused liver problems.
"It's been a tortuous process," said Tom Beyer, a research executive at Pfizer. "The body does not like drugs that get into the nervous system and there are barriers that are very difficult to cross," Beyer said.
Pfizer's drug, Alond, and Warner-Lambert's Zenarestat, are pills and attack neuropathy by inhibiting aldose reductase production. American Home Products Corp. (AHP) has a similar drug in an earlier stage of development.
Genentech's drug, Neuleze, is considered farthest along and company officials are hoping positive test results in 1999 will lead them to quickly seek Food and Drug Administration approval.
Neuleze, which is given by injection, uses a genetically engineered hormone that attempts to stimulate nerve growth.
Published studies show 75% of the 250 patients receiving three injections a week for six months reported fewer symptoms, compared to 49% of patients given a dummy drug. The only significant side effect is tenderness at the injection site.
Oliva was among those participating in tests of the drug. He said it restored reflexes in his ankles, which helped him walk again.
"I could function as a human being and not have to worry about pain from shoes or socks," he said.
Ultimately, researchers say a combination of drugs, including painkillers, will likely be used to treat neuropathy
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