Experimental Drug Shows Promise in Delaying Alzheimer’s Symptoms
New research offers hope that an experimental medication could postpone Alzheimer’s disease symptoms for millions. A US study involving 73 individuals with rare, inherited genetic mutations—predisposing them to excessive toxic amyloid protein in the brain—indicated that this drug delayed symptom onset. These individuals were highly likely to develop the condition by middle age, typically between their 30s and 50s.
Study Details and Findings
Participants received bi-weekly injections of gantenerumab, an antibody medication. Notably, in a smaller cohort of 22 participants treated for the longest duration—averaging eight years—the risk of developing Alzheimer’s symptoms decreased significantly, from nearly 100% to 50%. According to Dr. Randall Bateman from Washington University School of Medicine, the lead researcher, “Everyone in this study was destined to develop Alzheimer’s, and some are still symptom-free.”
He further stated, “The duration they will remain symptom-free is uncertain—it could be years or even decades. To maximize their chances of maintaining cognitive normalcy, we have continued treatment with another anti-amyloid antibody, aiming to prevent symptom development altogether.” Dr. Bateman concluded, “We have demonstrated that delaying the onset of Alzheimer’s symptoms is achievable, potentially granting individuals more years of healthy life.”
Amyloid and Early Intervention
It is understood that Alzheimer’s-related brain changes begin years, even decades, prior to the emergence of symptoms. This significant finding stems from an extension of the Knight Family Dominantly Inherited Alzheimer Network-Trials Unit (DIAN-TU) Alzheimer’s prevention trial.
Previous research indicated that gantenerumab successfully reduced amyloid levels and improved indicators of disease-related proteins. However, the initial study duration was insufficient to confirm symptom delay.
Subsequently, the study was extended, offering the drug to all participants and eliminating the placebo control group. Researchers then utilized data from comparable studies to estimate the typical age of symptom onset in these patients.
Researchers estimate that eight years of drug treatment approximately halved the risk of symptom development. Participants treated for only two to three years did not experience similar benefits, highlighting the importance of early intervention.
Implications for Broader Alzheimer’s Prevention
Despite the trial’s focus on a genetic form of early-onset Alzheimer’s, Dr. Bateman expressed optimism that these results could extend to all forms of the disease. He elaborated, “Should late-onset Alzheimer’s prevention trials mirror these DIAN-TU findings, preventative measures for the broader population may soon become available.”
Dr. Bateman concluded optimistically, “I am very hopeful as this could represent the first clinical evidence of future preventions for individuals at risk of Alzheimer’s. Delaying the onset of Alzheimer’s for millions may soon become a reality.”
Expert Reactions and Study Limitations
Promising Findings with Caveats
British researchers acknowledged the promising nature of the findings while also noting limitations in the study, published in Lancet Neurology. Professor Charles Marshall, a clinical neurology expert at Queen Mary University of London, described the indication that early amyloid beta reduction in the brain could postpone symptoms as “very exciting”.
However, he cautioned that the results stemmed from “a secondary analysis of a smaller group who received long-term treatment, making the findings less conclusive than primary trial outcomes”.
Concerns over Risk Reduction Claim and Control Group
Professor Robert Howard, an old age psychiatry expert at UCL, contested the researchers’ claim of a 50% risk reduction, deeming it a “misleading exaggeration”. Emphasizing the absence of a control group, Professor Howard asserted, “No responsible clinical trialist should claim a 50% reduction in dementia risk based on this data.”
Scientific Importance and Drug Availability
Professor Tara Spires-Jones, director of the Centre for Discovery Brain Sciences at the University of Edinburgh, recognized the study’s “scientific importance” as evidence supporting the potential of amyloid-lowering drugs to delay symptom onset.
Nevertheless, she reiterated concerns about the absence of a control group and the drug’s discontinuation by Roche due to its ineffectiveness in slowing symptoms in more common, non-genetic Alzheimer’s forms during a larger trial with over 1,900 participants.
Professor Spires-Jones concluded, “While this study does not definitively prove delayed Alzheimer’s onset and involves a drug unlikely to become available, the findings hold scientific promise.”