Investigational Therapy ALZ-801 Shows Clinical Efficacy in MCI Stage of Alzheimer Disease

Clinical trial data indicate that valiltramiprosate (ALZ-801; Alzheon) exhibits strong clinical efficacy at the mild cognitive impairment (MCI) stage of Alzheimer disease with no observed increased risk of brain vasogenic edema, according to a news release from Alzheon.¹

What Is ALZ-801 and Its Mechanism of Action?

ALZ-801 is a first-in-class, disease-modifying oral agent undergoing investigation for the treatment of patients with Alzheimer disease. The agent is designed to inhibit the formation of neurotoxic soluble amyloid-β oligomers that contribute to cognitive decline in individuals with the disease. Preclinical mechanism-of-action studies have demonstrated that ALZ-801 can completely block the formation of the neurotoxic oligomers at the dosage used in phase 3 clinical trials. Additionally, ALZ-801 employs an enveloping molecular mechanism of action intended to prevent the aggregation of soluble amyloid beta oligomers in the brain, which are associated with the onset and progression of cognitive impairment in those with Alzheimer disease.¹

In recognition of its therapeutic promise, ALZ-801 received a fast track designation from the FDA in 2017 for the treatment of Alzheimer’s disease.^1,2

Clinical Data Supporting the Benefits of ALZ-801

ALZ-801’s efficacy is supported by APOLLOE4 (NCT04770220),³ a randomized, double-blind, placebo-controlled, multicenter phase 3 clinical trial that assessed the efficacy, safety, tolerability, and biomarker effects of ALZ-801 in patients with early Alzheimer disease and an apolipoprotein E (APOE) 4/4 genotype. A total of 325 patients aged 50 to 80 years were randomly assigned to receive either ALZ-801 (265 mg twice per day) or placebo.^3,4

Early Alzheimer disease was defined as a Mini-Mental State Examination (MMSE) score of 22 to 30, which included MCI and mild dementia, and a Clinical Dementia Rating-Global Score (CDR-G) of 0.5 or 1. The trial’s primary end point was Alzheimer’s Disease Assessment Scale-Cognitive Subscale (ADAS-Cog13); the key secondary end points were CDR-Sum of Boxes (CDR-SB) and Amsterdam-Instrumental Activities of Daily Living. Another secondary outcome was Disability Assessment for Dementia (DAD).^3,4

The main imaging outcome was hippocampal volume on MRI; diffusion tensor imaging (MRI-DTI) assessed microstructural tissue integrity. Amyloid-related imaging abnormalities were monitored with MRIs every 26 weeks. Results were published in Drugs.^3,4

At 78 weeks, the overall efficacy population did not show significant effects on ADAS-Cog13 or other clinical outcomes compared with placebo (ADAS-Cog13: 11% slowing; P = .607; N = 320), but showed significant slowing of hippocampal atrophy (18%; P = .017; N = 290). Additionally, prespecified analyses by disease severity did not show significant clinical effects in mild Alzheimer disease (MMSE ≤26; N = 195). The prespecified MCI group (MMSE >26; N = 125) showed nominally significant positive effects on ADAS-Cog13 (52%; P = .041) and DAD (96%; P = .016), a positive trend on CDR-SB (102%; P = .053), significant hippocampal atrophy slowing (26%; P = .004), and positive gray/white matter effects on MRI-DTI.⁴

Further, in the MCI group, positive ADAS-Cog13 drug effects were observed to have significant subject-level correlations with positive effects on imaging outcomes. The most common adverse events were nausea, vomiting, and decreased appetite, but significantly, there were no increased risks of brain edema or microhemorrhages.⁴

“Valiltramiprosate has emerged as the only late-stage oral treatment with a potential to materially change the Alzheimer therapeutic landscape in the near future, and these data complete the picture showing how valiltramiprosate’s action leads to positive effects on cognition, daily function, and brain protection against atrophy,” Martin Tolar, MD, PhD, founder, president, and CEO of Alzheon, said in a news release. “In 2026, we will move forward with our plans for the next phase 3 study based on analyses from the APOLLOE4 phase 3 trial and its long-term extension. These efforts put us in a strong position as we focus on expanding the valiltramiprosate platform, developing new candidates, and investigating additional target groups.”¹

For patients with MCI in the placebo group, p-tau₂₁₇ was shown to increase approximately 17% from baseline over a 78-week duration, whereas those treated with ALZ-801 experienced a decrease in p-tau₂₁₇ of approximately 36% (difference: 53%). Among those with MCI who were treated with ALZ-801, there were both significant and meaningful relationships between decreases in plasma p-tau₂₁₇ and benefits on clinical outcomes in ADAS-Cog (r = 0.28; P = .039) and CDR-SB (r = 0.38; P = .005), as well as protection of hippocampal volume (r = 0.35; P = .013).¹

"Our new biomarker results offer robust biological validation for valiltramiprosate's upstream molecular mechanism, designed to inhibit formation of neurotoxic soluble amyloid oligomers, which are considered pivotal drivers of Alzheimer disease pathology,” said John Hey, PhD, chief scientific officer of Alzheon. “The consistent demonstration of Alzheimer’s positivity, early and sustained reductions in p-tau₂₁₇, and strong correlations with cognitive, functional, and imaging outcomes highlight the importance of p-tau₂₁₇ as a marker for disease progression and treatment efficacy, particularly in patients at earlier stages of Alzheimer disease."¹

ALZ-801 is undergoing evaluation in APOLLOE4-LTE (NCT06304883),⁵ the phase 3 long-term extension trial for APOLLOE4.¹

“These findings underscore the usefulness of plasma biomarkers in connecting Alzheimer disease pathology with clinically relevant outcomes,” Robert Rissman, PhD, professor of physiology and neuroscience at the University of Southern California, said in the news release. “The robust associations between decreases in plasma p-tau₂₁₇, benefits on cognition and function, and protection from brain atrophy offer valuable insights into disease mechanisms and further justify the advancement of valiltramiprosate as a potential disease-modifying therapy.”¹

REFERENCES

1. Alzheon reports plasma biomarker results from phase 3 and 2 studies of valiltramiprosate/ALZ-801, validating its first-in-class mechanism of action and underscoring benefits in cognition, function, and brain volume protection in Alzheimer’s patients. News release. Alzheon. February 3, 2026. Accessed February 5, 2026. https://alzheon.com/alzheon-reports-plasma-biomarker-results-from-phase-3-and-2-studies-of-valiltramiprosate-alz-801-validating-its-first-in-class-mechanism-of-action-and-underscoring-benefits-in-cognition-function-an/

2. FDA grants fast track designation to Alzheon’s ALZ-801 development program for the treatment of Alzheimer’s disease. News release. Alzheon. October 24, 2017. Accessed February 5, 2026. https://alzheon.com/fda-grants-fast-track-designation-to-alzheons-alz-801-development-program-for-the-treatment-of-alzheimers-disease/

3. An efficacy and safety study of ALZ-801 in APOE4/​4 early AD subjects (APOLLOE4). ClinicalTrials.gov. Updated November 10, 2025. Accessed February 5, 2026. https://clinicaltrials.gov/study/NCT04770220

4. Abushakra S, Power A, Watson D, et al. Clinical efficacy, safety and imaging effects of oral valiltramiprosate in APOEε4/ε4 homozygotes with early Alzheimer's disease: results of the phase III, randomized, double-blind, placebo-controlled, 78-week APOLLOE4 Trial. Drugs. 2025;85(11):1455-1472. doi:10.1007/s40265-025-02250-5

5. Long-term extension of phase 3 study of ALZ-801 in APOE4/​4 early AD subjects (APOLLOE4-LTE). ClinicalTrials.gov. Updated October 31, 2025. Accessed February 5, 2026. https://clinicaltrials.gov/study/NCT06304883