The drug, bexarotene, whose trade name is Targretin, quickly cleared abnormal plaques of a protein called beta amyloid from the brain and improved memory in three different mouse models of Alzheimer's disease, according to a study published Thursday in the journal Science. Beta amyloid is just one feature of Alzheimer's disease in humans.
Because bexarotene is already approved by the U.S. Food and Drug Administration for skin cancer, doctors can legally prescribe it "off-label" for other conditions. But Alzheimer's experts urge families to temper their hope until the drug is proved safe and effective by years of clinical trials -- a tall order for the country's 5.4 million patients and 14.9 million caregivers. "At this point in time, it would really be unethical for a physician to prescribe the medication and, I think, foolish for the patient to take it," said William Thies, chief medical and scientific officer for the Alzheimer's Association.
Like other cancer drugs, bexarotene can produc serious side effects, including headaches, hair loss, nausea and depression, and can increase cholesterol levels, according to the National Institutes of Health. In elderly Alzheimer's patients, many of whom take multiple medications, bexarotene could interact and interfere with other drugs. Thies said the Alzheimer's Association received more than a dozen calls about bexarotene after the Science study was published last week. Other doctors contacted by ABC News said they, too, had been contacted by caregivers clamoring for the drug.
"I just said we don't know if it's safe or effective," said Dr. George Grossberg, director of geriatric psychiatry at St. Louis University, who treats June Vasse. "I don't think we should be prescribing medications if we have no idea how to use them. It's irresponsible."