NAD Augmentation to Prevent or Reverse Alzheimer's Disease in People With Down Syndrome

The aim of the study is to determine the safety and tolerability of different increasing doses of MIB-626 (a microcrystalline form of β nicotinamide mononucleotide; NMN) given daily for 28 consecutive days to adults with Down syndrome (DS). The study will also explore how the drug moves through the body over time (pharmacokinetics or PK) and how the drug affects the body in different ways (pharmacodynamics or PD). The study participants will be monitored for adverse events and measurements to detect safety events will take place including laboratory tests of blood counts, chemistries and coagulation profile, and electrocardiogram (ECG). The trial will enroll a total of 24 adults with DS who are 18 years or older and are medically stable. People enrolled in the study will be randomly assigned to receive either the active intervention (MIB-626) tablets, or placebo tablets for 28 days. Study participants will be followed for an additional 28 days (total 56 days of follow-up). This study will also explore the effect of MIB-626 on different measures associated with aging and risk of Alzheimer's Disease (AD).