DORA and LP in Alzheimer's Disease Biomarkers

The overall goal of this project is to conduct an early stage (phase II) clinical trial of a dual orexin receptor antagonist (DORA), lemborexant, in cognitively normal older adults with amyloid deposition to demonstrate the feasibility and potential biological effectiveness of lemborexant's target engagement with multiple blood plasma and cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers. Orexins (also called hypocretins) are wake-promoting neuropeptides and blockade of orexin with a DORA increases sleep. The scientific premise of this project is that increased or enhanced sleep over 6 months by treatment with lemborexant will decrease the ratio of phosphorylated tau-181/tau-181 (pT181/T181) in blood and the concentration of CSF and plasma AD biomarkers (amyloid-β (Aβ), tau and phosphorylated tau (p-tau)) as well as neurodegeneration, inflammatory and synaptic AD biomarkers such as neurofilament light chain (NfL) (a non-tau marker of neuronal degeneration), soluble triggering receptor expressed on myeloid cells 2 (sTREM2) (a marker for immune response/microglial function), and neuronal pentraxin-2 (NPTX2) a marker for synaptic function) compared to placebo in amyloid-positive cognitively normal older adults. In addition, the investigators will also determine lemborexant's safety, pharmacokinetics (PK), and pharmacodynamics (PD) in this population. This study will enhance trial design and methods by providing critical information about dosing, safety, and target engagement of lemborexant on CSF and blood AD biomarkers to power phase III secondary prevention trials using lemborexant.