Promising new treatments for Alzheimer’s disease?

At present, it is possible to detect Alzheimer’s disease using tests aimed first at assessing memory loss, decreased functional abilities and behavioural changes. Other examinations, such as medical imaging and biological tests, can confirm the presence of beta-amyloid and tau proteins. However, a definitive diagnosis of the disease can only be established through a post-mortem examination of brain tissue.

Medical imaging 

Examinations of the brain using magnetic resonance imaging (MRI), computed tomography (CT) scans, and especially positron emission tomography (PET) scans, can guide the diagnosis by showing the accumulation of amyloid plaques in the brain. These techniques can also distinguish Alzheimer’s disease from other brain disorders, including age-related lesions, stroke, brain tumours, etc.

Biological tests

Testing cerebrospinal fluid for fragments of beta-amyloid and tau proteins helps complement the observations of plaques obtained through brain imaging.[4] However, collecting cerebrospinal fluid is much more complex than taking a blood sample, severely limiting its repeated use or application to large groups of patients.   

Can Alzheimer’s be diagnosed through a blood test?

While a number of blood tests can currently rule out various diseases that can cause Alzheimer’s-like symptoms (hypothyroidism, severe vitamin B12 deficiency, etc.), a new test (PrecivityAD) proposed in August 2019 could eventually simplify the diagnosis.[5] This test is based on the proportion of beta-amyloid fragments in the blood, the patient’s age and the presence or absence of copies of the APOE4 gene. Its distinctive feature is its relative simplicity (a blood test) combined with high accuracy (94%) in diagnosing early forms of Alzheimer’s disease. In some cases, this test could even diagnose the disease before a buildup of amyloid plaques is detectable by PET, a major advantage since certain new medications are intended for early forms of the disease.

Blood test for diagnosing Alzheimer's disease: Available soon? 

There is currently no truly effective treatment to slow the progression of Alzheimer’s disease, but the pharmaceutical community is excited about developing drugs that are increasingly efficacious.  

Relieving the symptoms  

Some of the symptoms (e.g. loss of mental faculties and behavioural changes) can be alleviated, or their progression can be slowed with drugs that limit the loss of acetylcholine, a very important neurotransmitter. These include donepezil,, galantamine and rivastigmine. A neuroprotective agent such as memantine can also be useful.[6]    

Treatment with antibodies

The pharmaceutical community is hard at work to find medications that directly target the abnormal beta-amyloid protein. By eliminating this protein before it forms permanent deposits, progression of the disease could theoretically be slowed. At least three of these drugs, in the form of anti-beta-amyloid monoclonal antibodies, are currently being studied.

• Aducanumab (Aduhelm) 

In 2021, an initial treatment based on antibodies (aducanumab/Aduhelm) was approved by the FDA in the United States, although it was controversial. Many scientists believe there is not enough evidence for the efficacy of this drug. Studies do show a reduction in amyloid plaques in the brain, but no decline in the progression of the disease’s symptoms. Biogen has until 2030 to prove the drug’s effectiveness for cognitive function, or it will be pulled from the market. So it is not surprising that no application for approval of Adulhem has yet been submitted to Health Canada.

• Lecanemab 

At the end of November 2022, the drug lecanemab showed more promise, this time with a reduction in the beta-amyloid protein, as well as a 27% reduction in the progression of the disease’s symptoms after 18 months of treatment. Lecanemab received unconditional approval from the U.S. FDA in July 2023 and, since May 2023, has been under review for approval by Health Canada.

• Donanemab 

We are looking forward to the official publication of the results of three more studies, this time involving donanemab, whose preliminary results published in 2023 appeared very promising. Further studies, which should be completed by 2027, are required before the U.S. FDA considers approval of this drug.

While some believe that lecanemab heralds a new era in treating the disease,[2] there are certain caveats.[7]

First, the treatment’s efficacy was measured over an 18-month period, but will these positive results continue?

Second, the drug costs nearly $40,000 per year, not including expenses related to diagnosis and follow-up (imaging, measuring proteins in cerebrospinal fluid and blood, etc.).

Third, implementing bi-weekly intravenous injection programs poses a major challenge for our already overburdened healthcare system.

Fourth, all these antibody-based treatments are linked with a risk of stroke in 15% of the patients treated. This risk is even higher when the APOE4 gene is present, i.e. in half of all patients! In addition, monitoring the health of the blood vessels in the brain would require a brain scan every two weeks.

Over the past 20 years, more than 200 clinical trials have turned out to be unsuccessful in treating Alzheimer’s disease. And today, there are just as many new studies underway on the same topic.

However, the results achieved so far with lecanemab and donanemab are generating much enthusiasm, because even if they do not cure the disease, they delay its progression, something we have not yet succeeded in doing.

If the success of monoclonal antibodies is confirmed, these treatments will also need to go hand in hand with new ways of screening for Alzheimer’s, such as blood tests. Indeed, lecanemab and donanemab are primarily intended for people in the early stage of the disease.

This revised edition reflects an updated version from the original version published on December 6, 2022, on our website. We have incorporated recent facts to offer you current and pertinent information.

We provide services that can help your doctor diagnose health problems and determine the appropriate treatment. 

• Medical imaging
• Blood tests
• Genetic tests

Do you have a medical prescription for any of these tests? Book an appointment online or contact Biron Health Group’s customer service at 1 833 590-2712.