The results of a new trial that tested the effectiveness of a drug for people with mild Alzheimer’s look promising, but there is still a long way to go. The drug seems to have slowed the decline in cognitive function associated with the disease over time.
The results, which were announced at the Alzheimer's Association International Conference 2015, were the conclusions of a trial that followed 1,322 people with mild Alzheimer's disease. All of the patients were given the drug Solanezumab and observed for two years.
Some patients had been treated with the drug in previous trials, and then continued to receive it for this two-year period. This group showed a reduction in mental decline by about a third. This suggests that the drug could have a disease-modifying effect if the patient is treated early enough.
The other patients who had also been enrolled in Solanezumab drug trials prior to this study were taking placebos but were transferred to Solanezumab for this trial. The overall benefits for these patients weren't as prominent as the patients who had taken the drug for a longer period of time, but there was still a reduction in symptoms.
"I think the effects that they showed were suggestive, but what they need to do is another independent study, because what they have shown has in a sense been reliant upon secondary analysis of two previous studies which did not meet their primary viewpoints."
These results are highly anticipated since Alzheimer's is the most common form of dementia. The symptoms of dementia include memory loss, difficulty with language, and trouble solving problems. It is estimated that nearly 44 million people worldwide have either Alzheimer's or a related dementia. There is currently no cure for Alzheimer's disease. The only medication available can manage the symptoms, but unfortunately cognitive decline is inevitable.
The development and progression of Alzheimer's is associated with an abnormal version of a brain protein called amyloid, which builds up in the brain and prevents nerves from functioning properly. These abnormal protein aggregates are called plaques and are thought to lead to cell death.
The drug that has been tested, Solanezumab, is an antibody that binds to these amyloid plaques and flushes them out of the brain.
Two previous trials were initially thought to be a failure. After re-examining the results, the scientists realized that there were some indicators of progress, but only in patients with mild stages of the disease. These patients showed some improvements in memory, thinking and problem-solving, and were the ones selected for this trial.
Ridley summarized that "this is interesting and potentially very significant."
"There's been implications from the field, for a long time, about whether going after amyloid is viable at all," he said. "I think what this data might do, more importantly if consolidated by an additional study, that this could show definitively that going after amyloid is a good idea."