Biogen tau drug diranersen slows early Alzheimer's decline

An experimental Alzheimer's drug that targets a key brain protein called tau slowed cognitive decline in patients with early disease, according to detailed clinical trial results presented on July 14. The findings, from a mid-stage study of the Biogen drug diranersen, offer new evidence that reducing tau may alter the course of the mind-robbing disease and have prompted the company to plan a larger, pivotal trial.

The Phase 2 trial, named CELIA, involved 416 participants with mild cognitive impairment or early-stage Alzheimer's. They were randomly assigned to receive one of three dosing regimens of diranersen or a placebo via injection into the spinal fluid every 12 or 24 weeks for 18 months. The drug is an antisense oligonucleotide, a type of treatment that works by silencing the gene responsible for producing tau, a protein that forms toxic tangles in the brain and is strongly linked to memory loss.

Researchers reported that diranersen reduced levels of tau in the cerebrospinal fluid by 50% to 65% across all dose groups. More notably, patients receiving the drug showed a slower rate of cognitive decline compared to those on a placebo across multiple assessment tools. The most...