Starting off our series of Naked Science is an article published in Nature that has caught the attention of a few news reporters recently, and well-deservedly so. The article delivers positive results from a phase 2 clinical trial investigating a new drug, called aducanumab, for the treatment of Alzheimer’s disease (AD). The researchers examined effects of a number of doses of this drug that targets and reduces amyloid-β plaques in the brain, which are characteristic of AD. These plaques are thought to be the primary cause of the neuro-degenerative disease and there are currently no treatments that target any underlying origins of AD.
The trial was well-designed throughout on a number of bases. It was double-blinded, meaning that the patients nor the researchers knew which treatment they were receiving, only a designated pharmacist or technician, which removes a major source of bias. The 165 patients initially included in the study were randomly assigned to receive either the drug or a placebo, by IV infusion every month for 1 year. The groups were generally well-matched before the start of the trial. Those included had to be between 50-90 years of age, have diagnosed early stage or mild AD, and have no other confounding pathology. Unfortunately, 40 patients dropped out of the study due to adverse side effects or withdrew consent. Side effects reported included headaches, urinary tract infections, imaging abnormalities and upper respiratory tract infections.
PET scan images of the brain before and following treatment or placebo showed significant reduction in the amyloid plaques in the treatment groups, in a time and dose-dependent manner. There were no improvements in the placebo group. A number of tests used to assess AD such as the Mini Mental State Examination showed that the treated patients had concurrently improved cognitive scores at the end of the trial, meaning less memory decline.
The results of this study truly are encouraging as it was a meticulous clinical trial conducted in people, demonstrating a promising reduction in the hallmark amyloid plaques and improved clinical cognitive outcomes after just 1 year of treatment. The next phase of trials is ongoing, including in the UK, to define optimum tolerable doses and longer-term effects which should be completed in 2020. It will be necessary for further studies to be completed with greater numbers of participants and in wider regions and ethnic groups. The study was not designed to measure cognitive outcomes in particular so more in depth studies will be required to hopefully confirm these preliminary findings.
Dr James Pickett, Head of Research at Alzheimer’s Society said:
‘These results are the most detailed and promising that we’ve seen for a drug that aims to modify the underlying causes of Alzheimer’s disease.’
It certainly is an exciting piece of research on a very worthy cause. 1 in 6 people aged over 80 years have dementia, extending to 1 million people by 2025. Watch this space!