A Pilot Electroencephalography Study of the Effect of CT1812 Treatment on Synaptic Activity in Patients with Mild to Moderate Alzheimer's Disease

Background CT1812 is a first-in-class, sigma-2 receptor ligand, that prevents and displaces binding of amyloid beta (A beta) oligomers. Normalization of quantitative electroencephalography (qEEG) markers suggests that CT1812 protects synapses from A beta oligomer toxicity. Objectives: Evaluate CT1812 impact on synaptic function using qEEG measurements. Design: Phase 2, randomized, double-blind, placebo-controlled, 4-week crossover study. Setting: VU University Medical Center and Brain Research Center Amsterdam, The Netherlands. Participants: Adults with mild or moderate Alzheimer's disease (AD). Intervention: A daily 300 mg dose of CT1812 or placebo for 4 weeks. Measurements: A resting-state, eyes closed qEEG assessment occurred on Day 1 and on Day 29 of Treatment Periods 1 and 2, and at follow-up. The primary endpoint was global relative theta power (4-8 Hz), along with secondary EEG measures including global alpha corrected Amplitude Envelope Correlation (AEC-c). Cognitive and functional assessments, fluid biomarkers, and safety and tolerability were assessed. Results: 16 patients were randomized, and 15 completed. A non-significant (p=0.123) but consistent reduction occurred in global relative theta power and in relative theta power in frontal, temporal, parietal, occipital and central (p<0.006) brain regions with CT1812. A nominally significant (p=0.034) improvement was observed in global alpha AEC-c. Adverse events occurred in 11 patients with CT1812 and 6 with placebo -most commonly nausea, diarrhea, and procedural headache. No severe or serious AEs, deaths or discontinuations were reported. Conclusion: CT1812 improved established EEG markers of spontaneous brain activity (spectral power, functional connectivity) in patients with mild-to-moderate AD, suggesting improved neuronal/synaptic function within a 4-week timespan.