It almost sounds too good to be true. But this much is real, so far: A skin cancer drug that's been around for 10 years has been found to sweep away the protein in the brain, amyloid beta, that's linked with Alzheimer's disease -- at least, in mice. What's more, the effects of the drug, bexarotene, were seen within hours, and within days, reversed the dementia symptoms of the rodents who received it.
Researchers at Case Western Reserve University School of Medicine in Cleveland, who made the discovery, cautiously say that this makes bexarotene, now used for T-cell lymphoma, "a pretty fantastic drug." The work was reported in the Feb. 9 journal Science. They also emphasize that the findings should be taken in context; animal results don't always translate to people.
“Making the leap from mice to humans is the most difficult step in drug development,” neurologist and neuroscientist Samuel Gandy of Mount Sinai Hospital in New York City says in Science News. “Based just on odds, I would bet against the drug, but the mechanism is novel and appealing, so I'm hoping that it beats the odds.”
Mice that are engineered to develop a form of Alzheimer's develop, as do humans with Alzheimer's, have high levels of beta amyloid. It causes tangles that scramble nerve cell communication, and clusters in large clumps known as plaques. Pathology tests on the mice showed that bexarotene lowered the levels of amyloid beta and also raised the levels of apolipoprotein E, another protein which regulates amlyoid beta to help keep amyloid beta levels low.
After 14 days of treatment, plaque levels fell by 75 percent, the Case Western team reported.
On the plus side, the drug is already FDA-approved, which means that human testing can begin relatively quickly. The bexarotene researchers have formed a company called ReXceptor Inc. and say they'll start human tests in two months.
This kind of development seems especially timely given a recent announcement than $80 million more is to be earmarked for Alzheimer's research beyond the $458 million originally allocated. The exact source of all that funding is still as unclear as whether mice can foretell the future for humans, however.
Image by law_kevin, used under a Creative Commons Attribution-Share Alike licensing agreement.