Alzheimer’s Drug Targeting Tau Protein Shows Mixed Results in Trial
6 verified4 unconfirmed2 contested
An experimental drug developed by Biogen that targets the tau protein showed potential in slowing cognitive decline in early Alzheimer's disease, according to results presented at the Alzheimer's Association International Conference in London. The drug, diranersen, is an antisense oligonucleotide designed to reduce production of tau, a protein linked to cognitive decline. In a Phase II trial involving around 400 participants with mild cognitive impairment or early-stage Alzheimer's, the drug lowered tau levels and appeared to slow cognitive decline compared to a placebo. However, the results included a puzzling finding: patients receiving the lowest dose showed the greatest cognitive benefit, contrary to the expected dose-response pattern. The drug is injected into the fluid surrounding the spinal cord. Biogen plans to move the drug into a larger Phase III trial to further evaluate its effectiveness.
What’s verified
Diranersen is an experimental antisense oligonucleotide developed by Biogen that targets the MAPT gene to reduce tau protein production.
The drug was tested in a Phase II trial on approximately 400 participants with mild cognitive impairment or early-stage Alzheimer's disease.
Diranersen reduced tau levels in cerebrospinal fluid and appeared to slow cognitive decline, with the lowest dose (60 mg every 24 weeks) showing a 26% reduction in cognitive decline compared to placebo.
The trial results did not show a typical dose-response relationship; higher doses did not provide greater cognitive benefit.
Side effects included injection site pain and temporary confusion, but no brain inflammation typical of anti-amyloid drugs.
Biogen intends to launch a Phase III study to confirm the drug's efficacy.
Where accounts differ
One source reported the trial included about 400 people, while the other specified 416 participants.
No other direct contradictions were identified across sources.
Not yet confirmed
One source reported that diranersen reduced tau levels by 50 to 65 percent from baseline, while the other did not specify a percentage.
One source noted that five of six cognitive tests showed slowed decline, but the other did not break down results by test.
Only one source mentioned additional experimental approaches, including a tau vaccine called AADvac1, the cholesterol-lowering drug obicetrapib for Alzheimer's risk, and Denali Therapeutics' technology to cross the blood-brain barrier.
It remains unclear whether diranersen could be used alongside or in sequence with existing anti-amyloid drugs.
Key figures
Dr. Cath Mummery (University College London) – lead investigator of the diranersen trial
Jessica Langbaum (Banner Alzheimer’s Institute) – researcher not involved in the study
Dr. Reisa Sperling (Mass General Brigham) – researcher not involved in the study
Heather Snyder (Alzheimer’s Association) – molecular neuroscientist
Dr. Adam Boxer (University of California, San Francisco) – lead of a new tau platform study
Rob Howard (University College London) – psychiatrist not involved in the study
Sources: abcnews.com, sciencenews.org
