Baxter's Immune Boosting Drug IVIg May Help Alzheimer's (Update2)
By Michelle Fay Cortez
July 30 -- Baxter International Inc.'s drug for immune system disorders also shows promise for treating Alzheimer's disease, a small company-funded study found.
Baxter's Gammagard boosts the body's natural defenses with antibodies extracted from human blood. It's now given to patients who don't make their own version of the immune system cells needed to prevent infections. Early research suggests it may attack certain proteins, called beta amyloid, that cluster around nerve cells in the brains of Alzheimer's patients.
In a study of 24 patients, those who received injections of the drug did better than those first given a placebo on tests of mental and physical function. The benefit increased with time, with Gammagard patients scoring 5.4 points higher than placebo patients on a 7-point scale of cognitive ability after nine months, the researchers said. Some of the very first patients to test the therapy are doing well years later, researchers said.
``We have patients now four and five years out who are still where they were when they started'' using Gammagard for Alzheimer's, Norman Relkin, a neurologist who in April reported positive findings for patients after six months, said in a telephone interview. ``Compared with what we can do now with available drugs, that's quite remarkable.''
About 5 million Americans have Alzheimer's disease, named for the German doctor Alois Alzheimer who described it in 1906. It progressively destroys brain cells, making it difficult for patients to think, remember and function. The condition is still only definitively diagnosed at autopsy, when amyloid protein plaques can be seen.
Currently, patients and their families have few options. The drugs approved in the U.S. to treat Alzheimer's ease symptoms for 6 to 12 months at most, according to the Alzheimer's Association, an advocacy group based in Chicago. While deaths from heart disease, breast cancer and stroke declined from 2000 to 2005, fatalities from Alzheimer's rose 44.7 percent, making it the sixth-largest cause of death.
As many as 2,000 people already get immune globulin for treating Alzheimer's on the mere suggestion it may work, said Rick Wise, an analyst at Leerink Swann in New York. The number could rise based on the data presented at the International Conference for Alzheimer's Disease in Chicago, he said.
If it's eventually approved for the condition, Gammagard could double its current sales, to $2 billion annually, Wise wrote in a July 11 note to investors.
Baxter, based in Deerfield, Illinois, rose $1.29, or 1.9 percent, to $68.57 at 4:00 p.m. in New York Stock Exchange composite trading. It has risen 29 percent in the 12 months.
One major advantage of Gammagard, which can cost as much as $5,000 a month, is knowing the dangers, since intravenous immune globulin has 30 years of use behind it, Relkin, director of the Memory Disorders Program at New York-Presbyterian/Weill Cornell Medical Center, said in a telephone interview last week.
The therapy can increase stroke risk in people with previous heart attacks or strokes, and may worsen kidney disease in those with compromised function, he said. In the new study of Alzheimer's patients, the most common side effects were rash and a drop in the blood count. Behavioral problems were more common in patients who initially were treated with a placebo.
Sixteen of the 24 patients in the study received Gammagard for 18 months, while the remaining eight initially were given a placebo. After six months of therapy, all patients were switched over to the drug. The six month findings were presented at the American Academy of Neurology meeting in April. The new results examined how the patients fared through nine months.
``It's certainly still early days,'' for using intravenous immune globulin, said Sam Gandy, an Alzheimer's Association adviser and associate director of the Mount Sinai Alzheimer's Disease Research Center in New York.
So far, there have been only a handful of studies on the treatment for Alzheimer's. Relkin said he first conceived of using products like Gammagard, called immune globulins or IVIG, after a study in 1999 found Alzheimer's patients had low levels of antibodies against the beta amyloid plaque. Gammagard and other intravenous immune globulins provide the full complement of antibodies produced by humans.
``It's throwing the kitchen sink at the disease,'' Relkin said. ``The body has some natural defenses against Alzheimer's disease because not everyone, as they get older, succumbs to it. Maybe giving patients the immune globulin of younger people that contains anti-amyloid antibodies will have an effect.''
A proposed larger, longer study involving 360 patients at medical centers around the country has been submitted to the U.S. Food and Drug Administration, Relkin said, and should begin shortly. The National Institutes of Health will help fund the study, conducted at medical centers that are part of the Alzheimer's Disease Cooperative Study group.