February 7, 2012
An experimental drug showed early promise in fighting Alzheimer’s. The drug, called gantenerumab, lowered levels of a toxic protein that builds up in the brains of those with the disease. Scientists hope that diminishing levels of the toxic protein, called beta-amyloid, will protect against memory loss and other symptoms of Alzheimer’s.
The drug is only available for experimental use, and much more study in larger numbers of people is needed to assess its safety and effectiveness against Alzheimer’s. Many medications show promise in early-stage trials but prove ineffective or too dangerous for clinical use on further testing. But the early results will lead to new studies of the drug as scientists seek ways to stem progression of the brain-ravaging illness.
For the study, researchers at three medical centers in Europe looked at 16 men and women with mild to moderate Alzheimer’s disease. Some received up to seven intravenous injections of the drug every four weeks, at higher or lower doses, while others got a placebo. They also underwent specialized brain scans to assess levels of beta-amyloid in the brain.
Gantenerumab is designed to enter the brain and bind to beta-amyloid, which forms toxic clumps called plaque. Once it binds to the beta-amyloid, it is thought to cause certain cells in the brain to remove the amyloid plaques. The brain scans showed that those getting the drug had lower levels of beta-amyloid in the brain than those receiving the dummy drug.
Other therapies have been tried to reduce levels of beta-amyloid in the brains of those with Alzheimer’s disease. Vaccines, for example, have been developed that reduce beta-amyloid buildup, but some patients receiving the vaccines have developed fatal brain inflammation. In the current study, some patients receiving the higher doses of the drug also developed brain inflammation, though none died.
The current study was small, and it is still unknown whether patients who got the drugs show improvements in memory or other symptoms. But an effective drug against Alzheimer’s is desperately needed. Current Alzheimer’s medications may ease symptoms for a time but do nothing to stop the downward progression of disease.
By stopping the buildup of beta-amloid, a key process in the progression of Alzheimer’s, scientists hope that drugs like gantenerumab may be more effective in actually halting progression of the disease. Such drugs, it is thought, may be most effective in the early stages of the disease, before damage to the brain becomes extensive and irreversible.
It may be possible, one day, to give drugs to people at risk for Alzheimer’s even before symptoms occur, actually preventing the onset of Alzheimer’s. Doctors now think that Alzheimer’s may take many years to develop before symptoms arise.
More studies of this and related drugs are being planned. The findings appeared in the Archives of Neurology, a medical journal from the American Medical Association.
Source: Susanne Ostrowitzki, Dennis Deptula, Lennart Thurfjell, et al: “Mechanism of Amyloid Removal in Paitents With Alzheimer Disease Treated With Gantenerumab.” Online first, Archives of Neurology, Oct. 10, 2011.