Researchers at Case Western Reserve University School of Medicine demonstrated that bexarotene (brand name Targretin) decreased the presence of amyloid beta, the protein that becomes out of control and forms plaque in the brain as Alzheimer's progresses. Bexarotene is approximately 10 years old and is an FDA approved drug for cutaneous T-cell lymphoma.
Levels of amyloid beta protein present in the brain responded quickly to the drug, decreasing notably within 24 hours, and by 75% after two weeks.
Even more importantly, the mice displayed a reversal of the cognitive problems they had exhibited, such as memory problems and impaired social behavior.
The spatial memory of mice was tested by observing their navigation through a maze. Their ability to construct a nest, which requires cognition but also social interaction, improved dramatically. Researchers also noted that the mice's memory for smells improved with the treatment. (As humans, our ability to detect or distinguish between odors often deteriorates as Alzheimer's progresses.) All areas showed notable improvement after just nine days of treatment with bexarotene.
Finally, the study demonstrated effectiveness in both early and later stages of Alzheimer's in the mice. This is important because most medications currently approved to treat Alzheimer's are helpful only in the early stages of the disease.
This drug is clearly effective in mice. What remains to be seen, but is surely hoped for, is its affect on people. Since the medication is already approved by the FDA, it is anticipated that clinical trials in humans will be able to occur relatively soon.
This study was published in the online journal Science.