Question: Can Alzheimer’s disease be prevented?
Answer: Not yet!
In spite of decades of intense and costly research, Alzheimer’s disease cannot be prevented, its inevitable progression cannot be halted, and even its symptoms cannot be dramatically improved. Research continues however, though this past year has seen a large number of very notable treatment failures, with drugs, vaccines and non-drug interventions.
One of the more disappointing failures was the recent announcement that the promising antibody treatment called Solanezumab did not slow memory and cognitive decline in a large, lengthy study of people with mild Alzheimer’s disease. This treatment, aimed at removing amyloid, one of the major pathologies in the brains of Alzheimer’s disease patients, has failed in many other studies with similar agents. Given the promise of this type of therapy however, there are still a couple of other similar antibody therapies that are going into large trials this coming year. These include trials of individuals who do not have Alzheimer’s disease diagnosed, but are at high risk for developing the disease based on family history and/or genetic profile.
Another major disappointment was the failure of a drug aimed at the other major pathological feature of Alzheimer’s disease – “tau”. Given that the majority of treatments that have been researched to date have focused on amyloid, this much newer focus is potentially exciting, and several antibody treatments for tau are in early development.
Non-drug therapies also contributed to the pessimism this year. While researchers have embraced treatments like exercise and cognitively stimulating activities based on modest improvements in cognitive function, these interventions have not yet demonstrated that they can effectively prevent or delay the onset of Alzheimer’s disease or other dementias. In a particularly disappointing study, six years of intensive vascular care (optimized treatment of hypertension, high cholesterol, and diabetes, plus healthy lifestyle advice) failed to reduce the number of new dementia cases when compared to standard treatment. The encouraging news however, is that numerous trials of non-drug/lifestyle interventions are already underway.
As an Alzheimer’s disease researcher for over a quarter of a century, you could legitimately ask me if all these failures have turned me into a pessimist. The truth is, that at the beginning of my career, when I lectured to both physician and lay audiences, I would always conclude my talk with the following uplifting comment: “I can confidently say, that within 10 years, we will have a cure for Alzheimer’s disease”. I stopped proclaiming this statement about a decade ago! And yet, I still remain hopeful that we will eventually find a way to prevent this illness. One of the truly optimistic findings from last year were the studies suggesting that in fact, the number of new cases of dementia being diagnosed each year is starting to decline. This was particularly noteworthy in the famous Framingham Heart Study from the United States which was published last year. The reasons for the decline are unclear, though healthier lifestyles, and better management of risk factors like high blood pressure, high cholesterol and diabetes could be contributing to these exciting results.
As noted, research continues in earnest. In Toronto, we are involved in a particularly exciting study aimed at preventing Alzheimer’s disease. Funded by Brain Canada and the Chagnon Family, this study of over 300 people who are at high risk for developing Alzheimer’s disease will follow people for up to five years or longer. We have chosen two groups of individuals who are high risk – those with mild cognitive impairment (but no dementia), and those who have experienced a clinical depression in the past. These individuals will attend an eight-week daily classroom course of “cognitive remediation” as well as receive a safe neurostimulation treatment called transcranial direct current stimulation. While we are about halfway through the study, we are continuing to actively recruit subjects for the trial. If you, or someone you know are interested in this study, please call us at 416-583-1350. Perhaps together we will find a cure for this terrible illness!