Advances in treatments for Alzheimer’s
An estimated 50 million people worldwide have dementia, mostly due to Alzheimer’s disease. It is a debilitating disease with incredibly profound impacts on patients, families and society as a whole.
Given the fear that many understandably feel about the disease, it is remarkable that there have been so few advances in treatment options in the last twenty years. The number of trials of prospective treatments that have ended in failure is almost legendary in the medical world.
Pfizer, one of the largest drug companies in the world, famously pulled out of all research into neurosciences (including diseases like Parkinson’s and Alzheimer’s) after some very large scale drug trials failed to deliver benefits to patients.
A trial shows promising results
The history of drug development in Alzheimer’s is so patchy that there is widespread caution about one new drug candidate, which has just showed some promising results in a Phase 2 clinical trial. The sense of deja-vu amongst doctors is almost palpable.
A proven benefit
In the TRAILBLAZER-ALZ trial 257 participants with early Alzheimer’s disease were randomly grouped to receive an anti-amyloid monoclonal antibody (Donanemab) or a placebo. Patients were treated intravenously every four weeks for 18 months.
Treatment with Donanemab resulted in 25-30% less cognitive decline than amongst the group who were given the placebo. Cognitive ability was measured using the Integrated Alzheimer’s Disease Rating Scale, a composite measure of cognition and the ability to perform instrumental activities of living.
The limits of the therapy
Although encouraging, especially given the list of historical failures, the secondary outcomes of dementia severity, cognition and functional ability all failed to show any difference. Nonetheless, the positive benefit means further trials Donanemab are warranted.
Sadly, the need to assess candidates who may be appropriate for treatment to monitor progress requires specialist MRI imaging, to look for bio-markers. This is expensive, time consuming and necessitates attendance at imaging centres.
The target area
Most treatments for Alzheimer’s so far have targeted the amyloid plaques that are characteristic of the disease. However, the failure of so many trials led many to question whether efforts are being directed in the right area.
In the trial just completed, Donanemab reduced plaques on imaging by 85%, normalizing levels in 68% of participants.
The positive trial results have implications for other anti-amyloid monoclonal antibodies too, including Aducanumab, which is currently waiting for approval for use from the US Food and Drug Administration. That approval, if it is granted, is anticipated in June 2021.
The right time to act
Even if the Phase 3 trials are successful or Aducanumab receives authorisation for use, significant barriers to successful treatment still exist. That means the time to act is at the earliest possible opportunity.
Early diagnosis is essential, because the benefits to treatment are only expected if therapy starts at the very earliest stages of disease. Many patients do not receive a diagnosis until they have experienced many years of symptoms.
To date, population screening for Dementia has not been considered appropriate, as there is little evidence to assess whether it can make a positive difference. However, cutting-edge technology is being deployed increasingly to assess and track cognitive function.
Mild cognitive impairment, which is a pre-cursor to many cases of Alzheimer’s can be found quickly online using validated tools from businesses such as Cambridge Brain Sciences. It is even possible to track cognitive health changes over time as part of corporate health screens.
Other changes are needed too
The high number of people with the disease, the lack of specialists and the expense and availability of bio-marker testing facilities all represent significant challenges to implementing any new treatments for Alzheimer’s.
Healthcare inequalities could also be made worse if treatments were provided only to those with access to facilities. Black, Hispanic and Latino people are all affected by Alzheimer’s at a greater rate than other ethnic groups, although they are less likely to receive a timely diagnosis and treatment.
Furthermore, the safety and efficacy of the new treatment amongst these groups cannot be verified yet, because only 3% of participants in the trial were Black and just 1% were Asian.
That new drug therapies for Alzheimer’s are showing promise, given the number of trial failures in the past, is an incredibly positive step. Yet the need for more research and investment in care provision is also being made increasingly clear too.
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