BOSTON – , represented by positive changes in plasma and imaging biomarkers of Alzheimer’s disease pathology.
Use of the drug, ALZ-801 (Alzheon), led to a significant reduction of plasma phosphorylated–tau 181 (p-tau181) , a marker of amyloid-induced neuronal injury in Alzheimer’s disease, as well as slowing of hippocampal atrophy and stabilization of cognition.
“The 12-month results of our phase 2 trial support the finding that ALZ-801 blocks misfolding of amyloid monomers and subsequent formation of neurotoxic amyloid oligomers, the key initial step in the amyloid aggregation cascade, which leads to a rapid and sustained reduction of brain neurodegeneration as measured by plasma p-tau181,” John Hey, PhD, Alzheon’s chief scientific officer, said in a statement.
“The severalfold greater reduction on the p-tau181 biomarker in plasma compared to plaque-clearing antiamyloid antibodies, combined with preservation of brain hippocampal volume and their positive correlations with cognitive benefits, further validate the disease-modifying effects of ALZ-801 in Alzheimer’s patients,” Dr. Hey added.
The results were presented at the 2023 annual meeting of the American Academy of Neurology.
ALZ-801 is an optimized prodrug of tramiprosate that has been shown to inhibit amyloid-beta 42 aggregation into toxic oligomers.
The ongoing phase 2 study is evaluating the effects of oral ALZ-801 (265 mg twice daily) on biomarkers of Alzheimer’s disease pathology for 84 adults with early Alzheimer’s disease who have either the APOE4/4 or APOE3/4 genotype. These genotypes represent the majority of patients with Alzheimer’s disease.
The mean age of the cohort was 69 years, and 51% are women; 70% had mild cognitive impairment, and 30% had mild Alzheimer’s disease. The mean Mini-Mental State Examination score for the cohort was 26.0. Roughly half were taking a cholinesterase inhibitor.
Significant plasma p-tau181 reduction was observed at 13 weeks. Levels were reduced by 41% by 52 weeks (P = .016). There was also a significant 5% reduction in plasma amyloid-beta 42 and 40 at 52 weeks (P = .002 and P = .005, respectively), Dr. Hey reported.
After 12 months of treatment, hippocampal atrophy was reduced by about 23%, and expansion of ventricular volume was reduced by about 15%, both in comparison with matched controls from the Alzheimer’s Disease Neuroimaging Initiative.
Composite cognitive z-score improved significantly at 13 and 26 weeks and remained above baseline at 52 weeks in comparison with matched ADNI controls. “These are very promising data,” Dr. Hey told conference attendees.
He noted that the safety profile of ALZ-801 remains favorable and consistent with prior safety data. Common adverse events were mild nausea and SARS-CoV-2 infection. There were no drug-related serious events or amyloid-related imaging abnormalities–edema (ARIA-E).
The phase 3 APOLLOE4 study of ALZ-801 is underway. This double-blind, randomized study is comparing oral ALZ-801 with placebo over 78 weeks for roughly 300 adults with early Alzheimer’s disease who have the APOE4/4 genotype. APOLLOE4 is expected to be completed in mid 2024.
The APOLLOE4 study is supported by a $47 million grant from the National Institute on Aging. The U.S. Food and Drug Administration has granted ALZ-801 fast-track designation.