A new treatment for early Alzheimer’s disease has shown encouraging results with UCLH consultant, Prof Cath Mummery, reporting both slower cognitive decline and significant reductions in the tau protein in the brains of participants.
The phase 2 Biogen sponsored clinical trial announced the findings for the experimental drug diranersen at the Alzheimer's Association International Conference (AAIC) 2026 and now plans to move the drug diranersen into Phase 3 testing.
The research was supported by the NIHR Biomedical Research Centre at UCLH.
Diranersen is an investigational therapy designed to reduce production of tau protein, one of the main features of Alzheimer’s disease. In the global CELIA study involving 416 people with early Alzheimer’s disease, the drug showed consistent clinical benefits across all doses studied over 18 months.
The strongest results compared with placebo were seen with the 60 mg dose, which slowed cognitive decline across different methods of measuring disease progress:
- 42% on the Alzheimer’s Disease Assessment Scale-Cognitive Subscale
- 50% on Mini-Mental State Examination MMSE,
- 26% slowing on the Clinical Dementia Rating-Sum of Boxes – a global measure of cognition and daily function scale.
Prof Cath Mummery, Consultant Neurologist at University College London Hospitals NHS Foundation Trust, said: “The CELIA data provide some of the clearest evidence that reducing tau pathology can translate into clinically meaningful benefit. The magnitude of tau reduction and cognitive benefit observed in CELIA is among the most compelling reported to date in Alzheimer’s disease drug development and supports advancing diranersen to Phase 3 development.”
The study also found that diranersen reduced cerebrospinal fluid total tau levels by 50–65% and was the first tau-directed therapy in a Phase 2 study to demonstrate reductions in both cerebrospinal fluid tau and brain tau pathology measured by PET imaging.
The treatment was generally well tolerated, with most adverse events reported as mild or moderate. More than 90% of participants who completed the placebo-controlled phase chose to continue into the long-term extension study.
Biogen says additional analyses from CELIA and the ongoing extension study will be presented at future scientific meetings as development of diranersen progresses.
Image: Adobe Stock / Lightfield Studios
