Alzheon's Valiltramiprosate Shows Promising Biomarker Results in Phase 3 Alzheimer's Trial
Key Insights
Valiltramiprosate demonstrated significant reductions in plasma p-tau217 (search) levels starting at 26 weeks, with MCI patients showing a 36% decrease compared to 17% increase in placebo group.
Strong correlations were observed between p-tau217 (search) decreases and improvements in cognitive assessments (ADAS-Cog), functional measures (CDR-SB), and hippocampal volume protection.
The Phase 3 APOLLOE4 trial confirmed 94% of APOE4 (search)/4 homozygote participants met FDA-approved Alzheimer's disease positivity criteria using plasma biomarker thresholds.
Alzheon announced plasma biomarker analyses from its APOLLOE4 Phase 3 and Phase 2 clinical studies of valiltramiprosate/ALZ-801, revealing robust evidence supporting the investigational oral agent's biological activity and novel mechanism of action in Alzheimer's disease patients. The results demonstrate early and consistent decreases in plasma p-tau217 (search) levels associated with improvements in cognition, function, and brain atrophy measures.
Significant Biomarker Reductions in MCI Patients
In the Phase 3 trial, participants receiving valiltramiprosate for 78 weeks showed reductions in p-tau217 (search) starting at 26 weeks that continued throughout the treatment period, with particularly pronounced benefits in patients at the Mild Cognitive Impairment (MCI) stage. For MCI patients in the placebo group, p-tau217 increased by approximately 17% from baseline over 78 weeks, while those receiving valiltramiprosate experienced a decrease of approximately 36%, translating to a 53% difference versus placebo.
Among the MCI group receiving valiltramiprosate, significant correlations were observed between decreases in plasma p-tau217 (search) and clinical benefits on ADAS-Cog (r = 0.28, p = 0.039), CDR-SB (r = 0.38, p = 0.005), and protection of hippocampal volume (r = 0.35, p = 0.013).
Strong Disease Validation Across Trials
Both studies demonstrated substantial enrichment for amyloid-driven disease using FDA-approved plasma biomarker thresholds. In the Phase 3 APOLLOE4 trial involving APOE4 (search)/4 homozygotes, 94% of enrolled subjects were confirmed as AD positive using the recently FDA-approved plasma p-tau217 (search)/Aβ1-42 ratio. The Phase 2 trial targeting APOE4 carriers showed even higher rates, with 97% of homozygote and 96% of heterozygote patients meeting the AD positivity threshold.
"These findings underscore the usefulness of plasma biomarkers in connecting Alzheimer's disease pathology with clinically relevant outcomes," stated Robert Rissman, PhD, Professor of Physiology and Neurosciences at the University of Southern California. "The robust associations between decreases in plasma p-tau217 (search), 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."
Mechanism of Action Validation
The biomarker results provide biological validation for valiltramiprosate's upstream molecular mechanism, designed to inhibit formation of neurotoxic soluble amyloid oligomers considered pivotal drivers of Alzheimer's disease pathology. Baseline plasma p-tau217 (search) levels were strongly correlated with both clinical and neuroimaging outcomes throughout the Phase 3 study, providing further biological support for the discovery that valiltramiprosate benefits are tied to treatment at the appropriate disease stage.
Within the Phase 3 MCI cohort, baseline p-tau217 (search) demonstrated significant associations in valiltramiprosate-treated participants with ADAS-Cog at baseline (r = 0.31, p = 0.019), CDR-SB (r = 0.40, p = 0.002), hippocampal volume (r = -0.532, p <0.0001), and cortical thickness (r = -0.60, p <0.0001).
Clinical Development Program
Valiltramiprosate/ALZ-801 is currently in Phase 3 development as a potential first-in-class, disease-modifying treatment for Alzheimer's disease. The investigational oral agent is designed to inhibit the formation of neurotoxic soluble beta amyloid oligomers that contribute to cognitive decline in individuals with AD. Preclinical studies have demonstrated that ALZ-801 can completely block the formation of these neurotoxic oligomers at the dosage used in Phase 3 clinical trials.
The APOLLOE4 Phase 3 trial evaluated the efficacy, safety, biomarker and imaging effects of 265 mg twice daily oral dose of valiltramiprosate in Early AD subjects with two copies of the apolipoprotein ε4 allele (APOE4 (search)/4 homozygotes), who constitute approximately 15% of Alzheimer's patients. This double-blind, randomized trial compared oral valiltramiprosate to placebo treatment over 78 weeks.
Clinical trial data indicate that valiltramiprosate exhibits strong clinical efficacy at the MCI stage and a favorable safety profile, with no observed increase in the risk of brain vasogenic edema. The drug received Fast Track designation from the U.S. Food and Drug Administration in 2017 for the treatment of Alzheimer's disease.
Future Development Plans
"Valiltramiprosate has emerged as the only late-stage oral treatment with a potential to materially change the Alzheimer's therapeutic landscape in the near future, and this data completes the picture showing how valiltramiprosate's action leads to positive effects on cognition, daily function, and brain protection against atrophy," said Martin Tolar, Founder, President, and CEO of Alzheon. "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."
The company plans to expand future research to include AD treatment and prevention in individuals carrying one copy of the APOE4 (search) gene, which constitute 65-70% of Alzheimer's patients. An ongoing long-term extension trial, APOLLOE4-LTE, evaluates valiltramiprosate for an additional 104 weeks of treatment for a total of 182 weeks or 3.5 years.