1. A documented 33% dementia chance post-stroke from an Australian study? May 2012.
2. Then this study came out and seems to have a range from 17-66%. December 2013.
3. A 20% chance in this research. July 2013.
A transcript of his remarks follows.
The way forward is more research, but it's research that has to be smart and learns from those failures. For example, it's only been in the last few years that Alzheimer's disease trials have, as routine eligibility criteria, the need to have evidence of the disease as shown by a biomarker, in particular a biomarker of amyloid. Early studies of drugs such as solanezumab that were targeting individuals with Alzheimer's disease dementia, we discover that in fact about 20% of the patients didn't have sufficient amyloid to meet the criteria for having Alzheimer's disease.
Well, now that we are using those markers as eligibility criteria, we're better able to target the drug through the disease. Fast-forward to the results of EXPEDITION 3, which used amyloid as an eligibility criteria: that drug didn't work as well, but the trends and the measures of cognition and function were generally favorable towards some sort of effect. So, now we have to explore issues around dosing of the drug.
That's a very specific example, but the point is that our failures are teaching us something and we're learning. The United States has a national plan for Alzheimer's disease and goal number one of that plan is to discover an effective treatment or a preventive therapy by 2025.
Prevention is a tall order. If taken literally, it means you take a treatment before you have any signs or symptoms of the disease and the treatment prevents you from ever developing those signs and symptoms. Will we achieve that by 2025 in Alzheimer's? I think it's unlikely. It's a complicated disease. There are many pathologies involved on top of an aging brain. But I think the signals from our studies are telling us that we may be able to slow down the decline seen over time in people who have Alzheimer's pathology, and delay the time before people lose the capacity to do their daily activities like managing their money or driving.
I think that's a reasonable hope. Some patients may respond very well to these therapies, some patients may not respond at all. But I think we can expect in the future that it will be a disease that is under our control.
Of course, we also have to understand that this disease sits upon an aging brain. Aging neurons don't work as well and we have to be thoughtful about what might be some interventions -- both therapeutic drugs, as well as lifestyle -- that can preserve our aging brain.
Finally, though, I think the key message is this. We're not going to drag our way out of this problem. We're going to have to learn how to live with cognitive impairment, and live well.