What a quick turnaround: a drug used to treat cancer can reverse Alzheimer's disease in mice – and it takes just 72 hours to work its magic. It remains to be seen if the drug has the same effect in people with Alzheimer's, though.
Alzheimer's disease is associated with deposits of beta-amyloid peptides in the brain. The build-up is thought to underlie the abnormal brain activity that leads to memory problems, and also kick-starts a chemical cascade that ultimately leads to the death of neurons.
Paige Cramer at Case Western Reserve University School of Medicine in Cleveland, Ohio, reckoned it might be possible to prevent that build-up using bexarotene, an anti-cancer drug. She reasoned that a healthy brain can clear beta-amyloid deposits through a process facilitated by a substance called apolipoprotein E (ApoE). ApoE is activated in part by a receptor called RXR – and bexarotene enhances the action of RXR.
When mice with Alzheimer's-like brain damage were given bexarotene orally, they were able to clear more than half of the beta-amyloid peptides from the brain within 72 hours. They also showed a rapid reversal of cognitive and social deficits.
Cramer says she hopes to begin phase 1 clinical trials in the next few months. "We believe that because bexarotene is approved [for use in humans], we will be able to transition much more quickly from basic research to the clinic," she says.