New research shows that Alzheimer's disease begins long before symptoms of memory loss appear, due to a toxic protein in the brain. The experimental drug NU-9 blocks this early damage in mice and reduces inflammation associated with disease progression. The treatment was given before symptoms appeared, thus targeting the earliest stage. NU-9 reduces levels of toxic beta-amyloid oligomers and protects neurons in a mouse model of Alzheimer's disease. It was originally being developed for ALS, where it received FDA approval for human clinical trials in 2024. Scientists are testing NU-9 in other models, including late-onset disease, and are monitoring the long-term effects on memory and neuronal health. This approach could transform the prevention and treatment of Alzheimer's disease.