slowing alz progression

A breakthrough in the treatment of Alzheimer’s disease using focused ultrasound  to enhance drug delivery may offer new hope for patients and their families. 

 

A PET scan of the brain of someone with Alzheimer’s disease typically shows a buildup of toxic amyloid proteins, or plaques that disrupt nerve cell function and destroy cells. Clearing these plaques is believed to slow the progression of Alzheimer’s. 

 

Last year, the FDA approved the use of a drug called aducanumab*, which uses antibodies to attack and reduce this toxic protein. The drug is both highly regulated and hard to come by, except at a handful of major medical centers. What’s more, not only is the traditional method of delivery cumbersome and slow—intravenous infusions administered over an 18-month period—but the procedure also carries a risk of bleeding in the brain.

 

Most antibody therapies, no matter how promising, have been stymied by a natural defense system in the brain: the blood-brain barrier (BBB). This protective mechanism blocks harmful substances from reaching the brain, but also impedes therapeutic drugs, limiting their effectiveness.

 

However, a team of researchers at West Virginia University/Rockefeller Neuroscience Institute have demonstrated a technique that delivers waves of focused ultrasound (FUS) to temporarily open the blood-brain barrier, allowing access to therapeutic drugs that are normally thwarted by the BBB. 

 

In a study published in the New England Journal of Medicine in January, three patients with mild Alzheimer’s received monthly infusions of aducanumab, followed by a painless, non-invasive procedure using a specially designed helmet to direct ultrasound energy to brain areas with high concentrations of plaque. Untreated areas of the brain acted as a control for comparison.

 

The ultrasound waves gently opened the blood-brain barrier, allowing the antibodies to enter the brain faster and work more effectively. By controlling how long the BBB remains open, risks of bleeding or swelling in the brain were minimized.

 

After six months, brain scans of the three subjects showed that using FUS in conjunction with the medicine cleared an average of 32 percent more plaques when compared to areas of the brain treated with aducanumab alone. 

 

While the proof-of-concept study “shows great promise for improving drug delivery to the brain,” according to its lead author, Ali Rezai, M.D., the treatment was never intended to serve as a cure for Alzheimer’s. And there remain numerous obstacles to overcome before the treatment becomes widely available.

 

“Drug development is slow, so it’s important to understand how early we are in the process,” said Mill Etienne, M.D., associate professor of neurology and medicine at New York Medical College in Valhalla and in practice at WMCHealth.

 

“What the medical community is excited about is that we’re seeing the first new treatment that can offer the possibility of delaying the progression of the disease. Imagine extending the number of years a person with Alzheimer’s can continue to be independent,” Etienne said. But he cautioned against getting hopes up too soon. “While this is a major advance, we’re still only at the beginning of what might be a new world of treatment.”

 

Still, the study represents an important breakthrough. Etienne suggests, “If this is of interest to someone (or a loved one) with Alzheimer’s, they should discuss it with their doctor. Ask if you or your loved one might be a candidate for the procedure**. When there’s a high enough demand for a new treatment, sometimes access can follow.”

 

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*Biogen, the company that makes aducanumab, is discontinuing the manufacture of the drug in 2024 as a treatment for Alzheimer’s in order to re-prioritize its resources. Dr. Etienne noted that similar drugs are available or in development.

**A brain PET scan is required for the procedure and is not always covered by insurance.