People with Alzheimer's disease are missing out on experimental treatments because they are not diagnosed early or accurately enough to be enrolled in clinical trials, according to a UK charity. Alzheimer's Research UK said that while trials of Alzheimer's drugs reached a record high this year, too few UK patients are participating due to delayed or non-specific diagnoses.
Growing Research, Limited Access
The warning suggests patients are being left behind as research gathers momentum and branches out to tackle the condition on multiple fronts, a strategy scientists consider crucial for halting the disease. Dr Sheona Scales, director of research at Alzheimer's Research UK, noted that the recent surge in clinical trials is driving demand for participants, but without a large and diverse range of patients to match to trials, the UK risks missing out. "People won't have access to the next generation of Alzheimer's treatments," she said.
More than 32 million people worldwide have Alzheimer's disease, the most common form of dementia, yet obtaining a diagnosis can take years. In the UK, one in three people living with the condition do not have a formal diagnosis. The precise mechanisms driving Alzheimer's remain unclear, but hallmarks include the buildup of abnormal proteins in the brain, such as amyloid plaques between cells and tangles of tau protein inside neurons.
Anti-Amyloid Drugs: Progress and Controversy
Hopes for treating Alzheimer's have been boosted by the arrival of anti-amyloid medicines like lecanemab and donanemab, approved by regulators worldwide. Clinical trials found that both slowed disease progression, though benefits were slight and neither was considered cost-effective for the NHS. A recent Cochrane review of seven anti-amyloid drugs sparked controversy by concluding that the class had no clinically meaningful impact over 18 months. Critics argued the analysis lumped lecanemab and donanemab with older, less effective medicines and suggested better results may come from earlier and longer treatment.
Shifting Trial Landscape
Dr Jeffrey Cummings of the University of Nevada has published an annual review of Alzheimer's drug trials for the past decade. The latest review, in Alzheimer's & Dementia: Translational Research & Clinical Interventions, reveals a shifting approach: fewer drugs target amyloid removal, while more target tau, inflammation, and other immune pathways. Cummings stated: "Anti‑amyloid medicines such as lecanemab and donanemab have been a crucial breakthrough... but they are only the beginning."
The number of candidate drugs trialled for Alzheimer's has risen by 40% in the past decade, with 158 potential medicines and 192 trials globally this year. Eight final phase-three trials are due to end in 2026. Another closely watched trial, Trailblazer-Alz 3, is testing donanemab in people with brain amyloid but no symptoms, potentially showing whether early intervention can protect against cognitive decline.
Diagnosis Hurdles
Diagnosing patients is a major obstacle for identifying suitable trial participants. In the UK, a third of patients lack a formal diagnosis, and among those diagnosed, the label is often general dementia—not precise enough for trial placement. Consequently, fewer than 1,000 UK patients are in phase 3 Alzheimer's drug trials. Scales emphasized: "Progress depends on finding the right participants... and that starts with early and accurate diagnosis."
