Band-aid for the brain?
Alzheimer’s drugs target symptoms not disease
Alzheimer's disease (AD) and similar neurodegenerative disorders have very complex pathologies that have challenged both the medical community and the pharmaceutical industry. With the first baby boomers retiring, however, pressure is expected to increase dramatically on drug companies to develop truly innovative therapeutics to help people cope with these diseases.
Over the decade spanning 1993 to 2003, five drugs were approved by the FDA for the treatment of AD, but rather than actually treat the disease, the drugs were designed to alleviate the neurological symptoms of the disease, including memory loss and trouble reasoning.
Most of the drugs fall into the category of cholinesterase inhibitors, which work by slowing the destruction of acetylcholine-a chemical messenger that travels between nerve cells-to effectively boost the neurological signals in the brain. The other drug is an NMDA receptor antagonist that protects nerve cells from excess levels of glutamate, another chemical messenger released when cells are damaged by disease.
Although these drugs have shown varying degrees of efficacy against AD, the search is ongoing for drugs that may prevent or reverse the effects of AD.
In November, researchers at Samaritan Pharmaceuticals presented preclinical data suggesting their lead AD candidate caprospinol (SP-233) was effective in decreasing the formation of amyloid-beta plaques in a rat model of AD and returning memory back to pre-disease levels. Days earlier, Anavex Life Sciences announced promising results of its candidate Anavex 1-41 in preventing neurologically destructive oxidative stress in an animal model of AD, and early in the month, Pipex Pharmaceuticals presented preclinical data for its copper chelator Coprexa showing the compound was able to reduce amyloid-beta deposition in mice.
And while the majority of current clinical trials continue to focus on symptom amelioration, there are several promising efforts to reverse or prevent amyloid-beta pathologies, including several vaccine candidates from companies such as Novartis, Wyeth and Affiris GmbH.