FDA Grants Fast Track Designation to Investigational Tau-Targeting Therapy for Alzheimer Disease

BIIB080 is the first tau-targeting antisense oligonucleotide therapy to reach clinical trials for Alzheimer's disease. Phase 1b trials showed positive cognitive trends and reduced tau protein levels in cerebrospinal fluid.
BIIB080 is designed to target microtubule-associated protein tau mRNA, aimed to reduce the production of tau protein.
The FDA has granted a fast track designation to BIIB080 (Biogen Inc.), an investigational antisense oligonucleotide (ASO) therapy targeting tau, for the treatment of Alzheimer disease (AD). BIIB080 is marked as the first tau-targeting ASO to reach the clinical trial stage for AD.
According to Mayo Clinic, about 6.9 million individuals in the US aged 65 and older live with AD, and more than 70% are aged 75 years and older. There is currently no cure for AD, and in its advanced stages, the resulting loss of brain function can cause severe complications.
As an ASO therapy, BIIB080 is designed to target microtubule-associated protein tau (MAPT) mRNA, aimed at reducing the production of tau protein. An excess accumulation of the protein in the brain is linked to AD, neurodegeneration, and cognitive decline.
Previous results from a phase 1b clinical trial assessed the use of BIIB080 among 46 individuals with mild AD. In the initial phase of the study, participants were randomly assigned to receive either a placebo or 1 of 4 different doses of BIIB080, including 10 mg, 30 mg, or 60 mg administered once every 4 weeks, or 115 mg given once every 12 weeks. Subsequently, in the long-term extension phase of the study, all participants, regardless of their initial treatment group, received either a 60 mg dose every 12 weeks or a 115 mg dose every 12 weeks.
Results from the study indicated positive trends across several exploratory measures related to cognition and their ability to perform daily activities. These findings build upon earlier results that demonstrated BIIB080 effectively reduced the levels of tau protein in the cerebrospinal fluid (CSF t-tau) and decreased tau accumulation as observed in PET scans across various regions of the brain.
Currently, a phase 2 CELIA clinical trial (NCT05399888) is being evaluated, assessing the use of BIIB080 among individuals with early AD and its role to slow the worsening of mild cognitive impairment or mild dementia. Researchers noted that the trial is fully enrolled, and data is expected to be provided in 2026.