Voyager to Advance 2 Tau-Targeted Alzheimer Therapies Toward Key Clinical Milestones

Voyager Therapeutics is advancing 2 investigational tau-targeted therapies for Alzheimer disease (AD) toward key clinical milestones expected before the end of 2026, as announced in a recent company news release. The company’s anti-tau antibody VY7523 is poised to deliver its first tau PET imaging data in patients and the tau-silencing gene therapy VY1706 preparing for first-in-human dosing.¹

The anticipated readouts will provide early clinical assessments of 2 complementary strategies for modifying tau pathology, targeting pathological tau directly with an antibody and reducing tau production through MAPT silencing, as the company continues to expand its AD pipeline beyond amyloid-directed approaches.

"We view tau as a critical disease-modifying target in Alzheimer's disease, and we believe recent third-party data validate this hypothesis," Alfred W. Sandrock Jr, MD, PhD, chief executive officer of Voyager, said in a statement.¹ "We continue to advance our 2 tau-targeted programs toward potential inflection points in clinical trials for Alzheimer's disease before the end of the year, with the tau-targeted antibody VY7523 expected to generate tau PET imaging data and the tau-targeted gene therapy VY1706 expected to begin dosing."

VY7523 Advances Into Multiple Ascending Dose Study

VY7523 is an investigational anti-tau monoclonal antibody designed to target pathological tau and potentially inhibit its spread through the brain. The therapy is currently being evaluated in a phase 1/2 randomized, placebo-controlled, double-blind multiple ascending dose (MAD) study in participants with early AD. The ongoing trial is designed to assess the safety, tolerability, pharmacokinetics, and preliminary efficacy of multiple intravenous doses of VY7523.²

The study is evaluating the agent across 3 dose levels, with participants receiving either the investigational therapy or placebo. Treatment lasts up to 6 months for the lower-dose groups and up to 12 months for the highest-dose group. Investigators are assessing tau PET imaging as an exploratory efficacy measure, including changes in tau burden at 6 and 12 months.

The program entered patient testing following a phase 1 single ascending dose (SAD) study in 48 healthy adults. In this previously completed, randomized, double-blind, placebo-controlled study, VY7523 was evaluated across 6 intravenous dose levels. Overall, the trial met its primary safety objective, with no serious or severe adverse events or infusion reactions reported. Serum concentrations increased in a dose-proportional manner, while the cerebrospinal fluid (CSF)-to-serum concentration ratio was 0.3%.³

The findings supported continued clinical development of VY7523 in patients with AD. The ongoing MAD study will provide an early assessment of the antibody's effect on tau pathology in patients, with initial tau PET imaging data expected in the fourth quarter of 2026.^1,2

VY1706 Advances Toward Clinical Testing

VY1706 is an investigational tau-silencing gene therapy designed to reduce tau production by delivering a vectorized small interfering RNA (siRNA) targeting MAPT mRNA. The therapy uses Voyager's TRACER AAV capsid platform and is administered as a single intravenous dose, with the approach designed to facilitate delivery of the MAPT-targeting siRNA across the blood-brain barrier and into the central nervous system.⁴

In June 2026, the FDA cleared Voyager's IND application for VY1706, enabling the company to initiate a clinical trial in adults with early AD. Dosing is expected to begin during the fourth quarter of 2026, marking the first clinical assessment of the therapy's safety and tolerability in humans.

The transition into clinical testing follows preclinical studies evaluating VY1706's distribution, pharmacologic activity, and safety. At the 2026 American Society of Gene & Cell Therapy Annual Meeting, investigators presented 3-month GLP toxicology data from nonhuman primates showing that a single intravenous dose produced dose-dependent reductions of 51% to 75% in MAPT mRNA and 48% to 64% in tau protein across key AD-relevant brain regions at 13 weeks. No adverse clinical pathology or histopathological findings were observed at the highest dose tested, 5 × 10^13 vector genomes/kg.⁴

Sustained Tau Reduction Observed Through 6 Months

Additional findings presented at the 2026 Alzheimer's Association International Conference extended the preclinical observations through 6 months. In the GLP toxicology study, a single intravenous administration of VY1706 resulted in sustained reductions of up to 75% in tau protein in key brain regions of nonhuman primates.⁵

The therapy was also well tolerated throughout the 6-month assessment period, with no adverse clinical pathology or histopathological findings reported at doses up to 5 × 10^13 vector genomes/kg.

Although the findings remain preclinical, the durability of tau reduction was considered notable for a gene therapy approach intended to produce a sustained pharmacologic effect following a single administration. The planned clinical study will determine whether the distribution, safety, and tau-lowering effects observed in nonhuman primates can be translated to patients with AD.

Two Strategies for Targeting Tau

The development of VY7523 and VY1706 reflects 2 distinct strategies for addressing tau pathology in AD. VY7523 is designed to bind pathological tau and potentially limit its propagation between neurons, whereas VY1706 is intended to reduce tau production by silencing MAPT.

The approaches come as tau-directed therapies continue to expand beyond amyloid-focused strategies in AD. Tau pathology is closely associated with disease progression and clinical impairment, but translating tau biology into effective disease-modifying therapies has remained challenging. Current development efforts include antibodies directed against different tau epitopes as well as approaches intended to reduce tau production at the RNA level.

For Voyager, the upcoming VY7523 tau PET readout will offer an early assessment of whether the antibody can affect tau pathology in patients with AD. VY1706, meanwhile, will provide an initial clinical test of whether systemic delivery of a tau-silencing gene therapy can safely achieve the sustained tau lowering observed in preclinical models.

Additional Pipeline Updates

Beyond its Alzheimer disease programs, Voyager's partner Neurocrine Biosciences has stated that it intends to initiate a clinical trial of NBIB-‘223, an investigational Friedreich ataxia gene therapy, during the second half of 2026, pending successful FDA IND clearance.¹

For the company's AD portfolio, the primary near-term focus remains on the 2 tau-directed programs. VY7523 tau PET imaging data and VY1706's entry into human testing are both expected in the fourth quarter of 2026, potentially providing the first clinical assessments of Voyager's complementary approaches to tau pathology.

References
1. Voyager Reports Second Quarter 2026 Financial and Operating Results.Voyager Therapeutics. News Release. August 6, 2026. Accessed: August 12, 2026. https://ir.voyagertherapeutics.com/news-releases/news-release-details/voyager-reports-second-quarter-2026-financial-and-operating
2. Voyager Therapeutics, Inc. VY7523-102: A Randomized, Placebo-Controlled, Double-Blind Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of Multiple Ascending Intravenous Doses of VY7523 in Participants With Early Alzheimer's Disease. ClinicalTrials.gov identifier: NCT06874621.
3. Ratti E, Butler M, Muse N, et al. Results of a Phase 1, randomized, placebo-controlled, double-blind study to evaluate the safety, tolerability, and pharmacokinetics of ascending single IV doses of VY7523, a tau-targeting therapeutic, in healthy adult participants. Presented at: Clinical Trials on Alzheimer's Disease; December 1-4,2025; San Diego, California.
4. Arora V, Ghosh V, Ito Y, et al. Intravenous Delivery of VY1706, a CNS Penetrant AAV Gene Therapy for Alzheimer's Disease, Demonstrates Compelling Pharmacology and Safety in a 3-Month GLP Toxicology Study in NHPs. Presented at: American Society of Gene & Cell Therapy Annual Meeting; May 11-14, 2026; Boston, Massachusetts.
5. Developing Topics: IND-enabling GLP NHP study of VY1706, a BBB-crossing AAV gene therapy targeting tau in Alzheimer's disease.Voyager Therapeutics. News Release. July 13, 2026. Accessed: August 12, 2026. https://www.globenewswire.com/news-release/2026/07/13/3326162/36461/en/voyager-demonstrates-single-iv-dose-of-vy1706-well-tolerated-reduced-tau-in-6-month-glp-toxicology-study-initiation-of-clinical-trial-in-alzheimer-s-disease-expected-h2-2026.html