Voyager Therapeutics Inc. (NASDAQ: VYGR) received U.S. Food and Drug Administration clearance for its Investigational New Drug application for VY1706, a gene therapy targeting tau protein in Alzheimer's disease patients. The company plans to begin dosing adults with early Alzheimer's disease in the second half of 2026.

VY1706 uses a vectorized siRNA that targets MAPT mRNA to reduce both intracellular and extracellular tau levels in the brain. The therapy is delivered through a single intravenous dose using Voyager's TRACER AAV capsid technology, which targets a receptor called ALPL to transport the treatment across the blood-brain barrier.

The upcoming clinical trial will be a multi-site, open-label, dose-escalation study enrolling up to 18 patients across three cohorts. Participants must have early Alzheimer's disease with confirmed tau pathology through PET imaging. The highest dose will not exceed 5E13 vg/kg, matching the top dose tested in preclinical safety studies.

Preclinical studies in non-human primates showed VY1706 reduced MAPT mRNA by 51-75% and tau protein by 48-64% in brain regions associated with Alzheimer's disease, including the entorhinal cortex, frontal cortex, temporal cortex, and hippocampus. Three-month toxicology studies found no adverse findings at the highest tested dose.

"The IND clearance for VY1706 is the first for a tau-targeted gene therapy," said Alfred W. Sandrock Jr., chief executive officer of Voyager.

The trial's primary endpoint will evaluate safety and tolerability, while secondary endpoints will assess tau biology changes through cerebrospinal fluid biomarkers and tau PET imaging.