Antibody clears Alzheimer’s protein from brain in clinical trial

Posted on 31st August 2016

In results from a phase 1b trial published today, a potential new drug called aducanumab has been shown to remove the build-up of the Alzheimer’s protein amyloid in the brain and slow the decline in memory and thinking skills in people with Alzheimer’s disease.

The results are published in Nature on Wednesday 31 August.

Aducanumab is an antibody designed to target amyloid, a protein that builds up in the brains of people with Alzheimer’s at an early stage in the disease process. Several drugs have been designed to target this process, but none have yet succeeded in clearing the protein and improving outcomes for patients in the final stages of clinical testing. The study published today is a phase 1b trial of aducanumab, in which researchers tested different doses and checked that the drug was safe and well-tolerated in people with early memory problems and mild Alzheimer’s.

Over the course of a year, the researchers gave monthly injections of aducanumab to 165 people at doses of either 1, 3, 6 or 10 mg/kg. Those included in the trial either had a diagnosis of mild Alzheimer’s or had early memory problems and evidence of high levels of the amyloid protein in their brain on brain scans. Participants had brain scans, blood tests and were assessed for their memory and thinking skills during the study. The researchers found that aducanumab reduced the levels of amyloid in the brain on brain scans, with the highest 10mg/kg dose having the greatest effect in clearing the protein.

The antibody was generally well-tolerated and considered safe enough for continued clinical development, although some participants experience side effects early in their course of treatment. Almost half of those on the highest dose of the drug experienced a condition called ARIA which is characterised by leakage of fluid from the blood into the brain. This is a recognised potential symptom of drugs targeting amyloid and an international working group now exists to better understand this side effect and how it can be avoided in future studies.

The researchers also reported that aducanumab dose-dependently slowed the rate of decline in memory and thinking skills in people receiving the drug, however due to the small size of the trial, the analysis was not statistically robust. These results support the continued clinical development of aducanumab, and recruitment into phase 3 trials involving greater numbers of participants is ongoing.

The phase 3 trials are currently recruiting for people in the UK who are between 50 and 85 and who have a confirmed diagnosis of mild cognitive impairment (MCI) or mild Alzheimer’s disease. Volunteers need to be willing to undergo testing for risk genes and have multiple assessments conducted, which will include brain scans and blood tests. In addition to this, taking part in the study would require a time commitment, as the volunteers would need to visit their research centre once a month to receive the trial drug or placebo. Anyone interested can sign up to Join Dementia Research at or by calling Alzheimer’s Research UK on 0300 111 5 111.

Dr David Reynolds, Chief Scientific Officer, Alzheimer’s Research UK, said:

“In continued efforts to develop the first disease-modifying treatment for Alzheimer’s disease, these results provide tantalizing evidence that a new class of drug to treat the disease may be on the horizon. This promising trial data shows that aducanumab is able to clear a key Alzheimer’s protein in people, building on earlier studies in mice. The findings suggest that aducanumab may slow memory and thinking decline in people with early Alzheimer’s and although the analysis is only exploratory in this early trial, it paints a positive picture for ongoing trials with the drug. The ultimate proof of success will be whether aducanumab is safe and effective in large phase 3 trials, which are currently recruiting participants across the UK. Some of the side effects seen in this study are concerning and will need addressing in the current trials, to ensure that people can stay safely on the drug for long periods.

“It has been over a decade since the last drug was licenced for use in people with Alzheimer’s, and there are currently no treatments able to stop the disease in its tracks. Anyone interested in volunteering for dementia research, including the current phase 3 trial of aducanumab, can sign up to Join Dementia Research at or by calling Alzheimer’s Research UK on 0300 111 5 111.”

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