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U of T neurology professor Sandra Black is cautiously optimistic around positive results of a new Alzheimer’s drug reported last week in the high impact journal Nature.

“It’s close to being very promising and potentially very exciting,” Black, a senior scientist at Sunnybrook Health Sciences Centre, told the Toronto Star, noting that Sunnybrook is a clinic site for the drug’s Phase 3 trials. “I think the bottom line is: stay tuned.”

Called aducanumab, the drug is a human anti-amyloid antibody infused intravenously. A small portion is able to pass through the blood-brain barrier, and binds to amyloid beta oligomers, small protein fragments that are very toxic to nerve cell synapses as well as other brain cells. As well the antibody binds to the characteristic Alzheimer’s “plaques” in the brain and helps to clear out these clumps of damaging amyloid-beta proteins.

After a year of treatments, patients receiving the highest dose of the infused drug had a significant decrease in their amyloid plaques (tested via PET imaging). It’s a promising finding but the study was small: just 165 U.S. patients in the early stages of Alzheimer’s – and 40 of those patients dropped out.

While the study was not powered to detect clinical changes, the researchers also documented a “dose-dependent slowing of clinical progression” of the disease. Larger studies would be needed to validate this finding.

The prevailing theory of Alzheimer’s disease – still being tested rigorously by scientists worldwide – is that protein-related toxicity is the primary cause of the cellular level dysfunction that leads to the neurodegeneration found in Alzheimer’s disease. This current study adds another piece of evidence to support that theory.

For more information about the Phase 3 studies of aducanumab, including information about participating centres, visit