Phase IIa L-serine Trial for eAD

L-serine (C3H7NO3; 105.09 g/mol; synonym (S)-2-amino-3-hydroxypropanoic acid) is a naturally-occurring dietary amino acid. It is abundant in soy products, some edible seaweeds, sweet potatoes, eggs, and meat. Since some L-serine is produced by astrocytes in the brain, it is considered a non-essential amino acid. L-serine is directly involved in the biosynthesis of purines, pyrimidines, and other amino acids. Serine residues are found in most proteins and within proteins function as a site for phosphorylation. L-serine is considered as GRAS (generally recognized as safe) by the FDA and has been approved as a normal food additive under CFR172.320. It is widely sold as a dietary supplement. A pilot study of L-serine supplementation of 14 patients with hereditary sensory neuropathy has been published, and subsequent trial is on-going (ClinicalTrials.gov identifier NCT01733407). The authors did not report adverse effects at doses of 400mg/kg/day, which for an average American of 75.5kg is about 30 grams, the dose which we propose to use in this study. L-serine will be administered orally through gummies. Each gummy contains 1 g L-serine (treatment) and will be packaged in a foil packet containing 15 pieces to be taken both morning and evening for nine months. The placebo will be a gummy containing no L-serine, packaged and taken in the same manner. In order to assess tolerability in patients, we have designed a 4 week dose ramp-up. We will monitor side-effects and amino acid balances in blood samples in the early Alzheimer's Disease patients during a dose ramp-up period. If a patient cannot tolerate the full dose of gummies, they will remain in the study taking a total of 1 package of gummies split into two time periods within the day. The same ramp-up schedule and procedures will be observed for both placebo and L-serine patients. Patients will be assessed at baseline, 3 months, 6 months, and 9 months.