Scans of a brain

What is Aducanumab and what could this dementia drug mean for people with Alzheimer's disease?

The FDA has approved the dementia drug Aducanumab for clinical use for people living with Alzheimer's disease in the USA. Find out more about the drug, its path to approval, and what it means for people with dementia in the UK.

Over 850,000 people are living with dementia in the UK and sadly there are no treatments that can slow down or stop it from progressing. 

Research is providing hope. Today there are 126 drugs in clinical trials to treat Alzheimer‚Äôs disease - one of the main causes of dementia. 

There are still major challenges in developing treatments. Unfortunately many drug trials have not shown significant benefits for people with dementia. However, in 2019, results from clinical trials testing a drug called Aducanumab showed some promise in slowing the progression of symptoms in people with early-stage Alzheimer‚Äôs disease. 

Over the last 18 months, the Food and Drugs Administration (FDA) - the drug regulatory body in the USA - has reviewed the evidence on how effective Aducanumab is at slowing the progression of Alzheimer’s disease. The FDA has now approved the drug for clinical use in people with Alzheimer’s disease.

‚ÄėThis is the first ever Alzheimer's disease modifying drug to be approved, representing a promising step in the quest to find dementia treatments‚Äô

However, it is currently only available for use in the USA. 

Biogen ‚Äď the pharmaceutical company who owns Aducanumab ‚Äď have also submitted an application to the European Medicines Agency (EMA), the EU equivalent of the FDA. UK regulatory bodies will also rigorously review the clinical trial data showing the effects of Aducanumab. These bodies will then make a decision as to whether to approve the drug for use in Europe and in the UK. 

What is Aducanumab? 

Aducanumab is an antibody therapy that targets amyloid beta protein. This protein accumulates in clumps in the brains of people with Alzheimer‚Äôs disease. Researchers believe these clumps play a role in damaging brain cells, ultimately causing them to stop working and die. This gradually leads to the symptoms we see in people with Alzheimer‚Äôs disease, such as dementia. 

Alzheimer’s Society funded work leading to the discovery of the first Alzheimer’s gene in 1991. This work, led by Professor John Hardy, provided the first piece of strong evidence that a build up of amyloid in the brain may play a pivotal role in the development of Alzheimer’s disease and could the trigger the disease.

The ‚Äúamyloid hypothesis‚ÄĚ has hugely influenced Alzheimer‚Äôs disease research. Now, nearly 30% of current disease-modifying treatment in phase III trials ‚Äď including Aducanumab ‚Äď aim to prevent the disease through targeting amyloid.

What have been the results of clinical trials using this drug? 

Early stage, smaller trials  

After initial trials showed that Aducanumab was safe to use in humans, a further trial called PRIME assessed if the drug could slow the progression of Alzheimer’s disease in people who were in the early stages of the disease. This included people who had mild cognitive impairment (MCI) or early-stage dementia.

The PRIME trial started in 2012. Biogen reported treatment led to a reduction in amyloid levels in the brain. The company said the drug appeared to slow the rate of cognitive decline for people with mild Alzheimer‚Äôs disease receiving the drug. 

Large and longer trials  

These findings allowed Biogen to conduct larger clinical trials of Aducanumab. Two trials, called ENGAGE and EMERGE, collectively enrolled over 2,500 people with MCI or early-stage dementia caused by Alzheimer’s disease.

The changes in the brain caused by Alzheimer‚Äôs disease tend to start many years before symptoms show. This means that earlier treatment is likely to have a better chance of being effective. The main aim of the ENGAGE and EMERGE trials was to see if Aducanumab could reduce signs of cognitive decline in the people with MCI and mild dementia. Participants received different doses of the drug, and were compared to people receiving a placebo treatment. The placebo contained no active ingredient. 

The two large Aducanumab trials began in 2015, but were cut short in March 2019. Although the EMERGE trial was said to be ‚Äėtrending positive‚Äô in terms of potential outcomes, early results indicated the ENGAGE study was not going to be successful. In order to progress, Biogen had specified that both trials needed to be heading in the right direction. The results meant that both trials were terminated.  

However, further analysis using data from more participants changed Biogen‚Äôs initial conclusions. The EMERGE trial data showed a positive effect in people given Aducanumab compared to placebo. The ENGAGE trial however only demonstrated a clinical benefit in a subgroup of people on a higher dose of Aducanumab ‚Äď only specifically in relation to memory and thinking skills. As a result, Biogen restarted enrolment of participants back into the clinical trials, which are now due to finish in 2022.

‚ÄėBoth trials showed a reduction in the levels of amyloid beta in the brain of those treated.‚Äô

The reanalysis of EMERGE and ENGAGE suggested some reduction in cognitive decline in people taking the higher dose of Aducanumab. It will be important to see the clinical findings of the full trials once completed in 2022. This will give us a better idea of Aducanumab‚Äôs effectiveness.  

Are there any known side effects from Aducanumab?

From the clinical trials, the main side effect of Aducanumab treatment reported was amyloid-related imaging abnormalities (ARIA). These are thought to be micro-bleeds or swelling in the brain and have been reported in other anti-amyloid trials, particularly following high-dose treatment.

Biogen reported individuals with ARIA showed mild to moderate symptoms, with some displaying dizziness, headaches and nausea. These effects mean it will be important to continually monitor patients on undergoing Aducanumab treatment. 

How has the research progressed for Aducanumab?

October 2019

Biogen announced they would be submitting an application to the FDA to license Aducanumab.

November 2020

The FDA brought together and publicly broadcast an independent advisory committee meeting to discuss the evidence. The advisory committee voted against the approval of Aducanumab as a treatment for people with early Alzheimer‚Äôs disease. The committee felt there was insufficient evidence to show it is effective. 

June 2021

The FDA have now reached their final decision, approving the drug for use as a treatment for people living with Alzheimer’s disease at any stage. This decision was largely made on the drug's ability to reduce amyloid in the brain. However, it is still unclear whether this action will provide a clinical benefit.

The FDA used the ‚ÄėAccelerated Approval pathway‚Äô for this decision. This pathway enables earlier access to treatments which could benefit people living with serious diseases like Alzheimer‚Äôs disease. The FDA uses the pathway where there are very few other treatments available and where a new treatment is expected to have a beneficial effect.

‚ÄėThe FDA has concluded that the benefits of Aducanumab for patients with Alzheimer‚Äôs disease outweigh the risk of the treatment.‚Äô

The FDA has also requested a further clinical trial after this approval to ensure Aducanumab really is beneficial for people living with Alzheimer's disease. The approval means Aducanumab will be able to be accessed by people with Alzheimer’s disease in the United States.

What does this mean for people living with dementia in the UK?  

Whilst exciting that research has brought us to this point, Aducanumab is not yet available to people with Alzheimer‚Äôs disease in Europe or the UK.  

Biogen have also applied to the EMA for Aducanumab approval, which we await the outcome of. Any new medication will also need to be reviewed by UK regulatory bodies and by the National Institute of Health and Care Excellence (NICE) before it might be made available through the NHS in the UK.

‚ÄėIt is unlikely we will know if Aducanumab will be approved and ready for use in the UK until at least 2022.‚Äô

Taking a step back

It is possible the EMA could call for further trials to provide additional evidence of the benefits of this drug for people with early Alzheimer‚Äôs disease. It is essential that regulatory authorities are confident that this drug is effective and safe before it may be made available to people with Alzheimer‚Äôs disease. 

It is also important to remember that, if approved, Aducanumab has only been tested in people with early-stage Alzheimer’s disease.

Although the FDA is making the drug available to all people living with Alzheimer‚Äôs disease, it is unclear how beneficial this treatment will be in more advanced stages. Also, in the UK, the drug may only be approved for those living with the early-stages of the condition based on the current data.

‚ÄėThe decision by the FDA to approve Aducanumab has not been without controversy, splitting the dementia research community.‚Äô

Some believe it will bring greater focus and investment to the field of dementia research. Others believe there is not enough evidence to demonstrate a true benefit for people with Alzheimer’s disease.

The next steps for the drug in Europe and UK are likely to continue to split opinion. However, the results of additional clinical trials will help to bring clarity to the effectiveness and benefits of Aducanumab.

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This article was first published on 8 June 2021 and last updated on 14 June 2021.

15 comments

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How can my mother get this drug? She has been diagnosed with early CAA she is under UCL hospital.

This is helpful
0

Hello,

We're very sorry to hear about your mother, it must be a really difficult time for you both.

As stated in the article, 'Aducanumab is not yet available in Europe or the UK.' and 'It is unlikely we will know if Aducanumab will be approved and ready for use in the UK until at least 2022'.

Please know that if you need advice, support, or information, you can always call our support line on 0333 150 3456 and speak to one of our trained dementia advisers. More details about the support line (including opening hours) are available here: https://www.alzheimers.org.uk/dementia-connect-support-line

We hope this helps.

Alzheimer's Society blog team

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,It has enlighten my understanding of the disease/condition and prospects of coming up with treatment.

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Hoping we get a chance to beat this monster

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Surely people would rather take the chance than allow the disease to take its course

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What are rhese "nasty" side effects, are they related to ALZHEIMER'S DISEASE or other effects on the Central Nervous System? Please be specific.
Thank you.

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Hello Siegfried Frank,

From the clinical trials, the main side effect of Aducanumab reported was amyloid-related imaging abnormalities (ARIA). These are thought to be micro-bleeds or swelling in the brain and have been reported in other anti-amyloid trials, particularly following high-dose treatment. Biogen reported individuals with ARIA showed mild to moderate symptoms, with some displaying dizziness, headaches and nausea. These effects mean it will be important to continually monitor patients on undergoing Aducanumab treatment.

More research is needed to investigate the link between epilepsy and dementia. Hopefully, this work will give us a better understanding of the link between the two conditions, which may help with the development of more effective therapies.

We hope this is helpful for now.

Alzheimer's Society Research Communications Team

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No mention in article about its effect with patients who also have epilepsies.
Wife became epileptic 7 years before diagnosis of Alzheimer's. Cannot use current Alzheimer's drugs since they would trigger epileptic fits.
She can not be alone with this problem.

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Hello David, thanks for getting in touch.

In trials so far for aducanumab, there has been no mention of treatment for people living with Alzheimer’s disease who also have epilepsy. It is unclear if these tests will take place, but we will be sure to share an update if they do.

More research is needed to investigate the link between epilepsy and dementia. Hopefully, this work will give us a better understanding of the link between the two conditions, which may help with the development of more effective therapies.

We hope this is helpful for now.

Alzheimer's Society Research Communications Team

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I have read very nasty side effects with this drug and no real evidence it helps at all

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3

Hi Elaine can you tell me what the nasty side affects are and where or how you know about them please

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Hi silvi
I will have to check back on my emails, sorry memory not so good!

But as for side effects, the chances of making the dementia worse are very high as it does unquantifiable damage to the brain. In fact there is no real evidence that this drug works. So do you take the chance when the scales are more weighed to damage rather than helping. It's scary that the FDA has approved this with such worrying side effects. It could be available in the states relatively soon and what happens in America sooner or later happens here.

If you are not aware of the clinical results will the danger be fully explained if and when it arrives here?

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Hi Elain and Silvi,

Results of additional clinical trials will help to bring clarity to the effectiveness, the benefits and any potential side-effects of Aducanumab. We will continue to update this article with more evidence-based information as soon as it is available.

Thank you,

Alzheimer's Society Research Communications Team

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Brain swelling according to Dr Randi. Maybe other drugs to treat brain swelling!

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Hello Elain,

From the clinical trials, the main side effect of Aducanumab reported was amyloid-related imaging abnormalities (ARIA). These are thought to be micro-bleeds or swelling in the brain and have been reported in other anti-amyloid trials, particularly following high-dose treatment. Biogen reported individuals with ARIA showed mild to moderate symptoms, with some displaying dizziness, headaches and nausea. These effects mean it will be important to continually monitor patients on undergoing Aducanumab treatment.

More research is needed to investigate the link between epilepsy and dementia. Hopefully, this work will give us a better understanding of the link between the two conditions, which may help with the development of more effective therapies.

We hope this is helpful for now.

Alzheimer's Society Research Communications Team

This is helpful
0
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