DEAR DOCTOR K:
Is there anything new on the horizon for treatment of Alzheimer’s disease?
Alzheimer’s disease affects more than 5 million people in the United States, alone. And that number is expected to more than double by 2050. I spoke to my colleague Dr. Gad Marshall about advances in Alzheimer’s treatment. He is an assistant professor of neurology at Harvard Medical School.
Medical research has discovered that two proteins found in the brain are important in causing Alzheimer’s disease. The first is called amyloid-beta. This protein clumps together to form plaques in the brain. These plaques have long been recognized as a hallmark of Alzheimer’s disease.
Unfortunately, drugs and vaccines that target amyloid-beta have not so far proved very effective. The problem may be that by the time Alzheimer’s symptoms appear, plaque formation is already extensive. Much damage already has been done, and treatment may come too late.
Through research, doctors have developed techniques for spotting plaques of amyloid-beta when they are first forming, in younger adulthood. With that tool in hand, doctors are now conducting large studies to see whether treatment to lower amyloid-beta levels at a much earlier stage will reduce the risk of Alzheimer’s disease.
Recently, new potential treatments have focused on a different protein: tau. Tau clumps together in the brain to form what are called “tangles.” Like the plaques of amyloid-beta, the tau tangles have long been a hallmark of Alzheimer’s disease. Tau helps to transport nutrients into the cells and to move waste out of cells.
However, when tau protein forms tangles, brain cells have trouble getting enough nutrients and eliminating waste. As a result, brain cells slowly die. In a recent report in the journal Brain, researchers examined the brains of more than 3,600 people who had died. They concluded that the presence of dysfunctional tau protein may be more important than amyloid-beta in causing the cognitive decline and memory loss seen in Alzheimer’s.
Tau tangles occur early in the disease process. The hope is that by designing treatments that target tau, we can prevent symptoms of Alzheimer’s, or slow down symptoms in those who already have signs of dementia. The challenge is to focus on the right ones. You need normal tau protein in the brain. The trick is to remove only the abnormal tau protein that is damaging nerve cells.
Several tau-focused drugs are in development. They include:
- LMTX. This drug is supposed to reduce the clumping together of abnormal tau proteins.
- TPI 287. This drug is designed to stabilize the nerve cell microtubules that are damaged by abnormal tau proteins.
- NILOTINIB. This FDA-approved leukemia drug is thought to help clear abnormal tau from the brain.
Leading Alzheimer’s researchers are optimistic that effective tau-focused treatments will be available within the next five to 10 years. You can learn about studies underway to treat Alzheimer’s disease at the website ClinicalTrials.gov. It lists the studies that are actively recruiting patients.