PROJECT SUMMARY: This R44 application is focused on preparations for a phase 1b clinical study to look for early clinical signs of efficacy/proof-of-concept by evaluating the response to treatment of relevant serum and CSF biomarkers in a double blinded study of patients with Alzheimer’s Disease. The proposed work is designed to support longer term dosing required to see an effect on biomarkers. The prevalence of AD is increasing worldwide. There remains an urgent need for disease modifying drugs for AD that are cost-effective and easy to administer. This program is progressing to fill the need with an economical, disease-modifying drug that is stable, oral, and can be self-administered. If successful, it will have a tremendous impact on the more than 6.5 million Americans who currently have AD (projected to be 12.7 million by 2050) and their caregivers, and will help reduce the current cost of $321 billion (projected to be $1 trillion by 2050) to our nation (Alzheimer's Association 2022 Alzheimer's Disease Facts and Figures). We have now completed all preclinical work for our IND application to FDA for our first-in-human phase 1a study. A summary of this work follows: TO-0582 demonstrated pharmacologic activity in two mouse models of tauopathy (the htau model that has human tau with all 6 isomers best representing tau aggregation in AD and in the JNPL3 mouse model that has a P301L mutation and represents four-repeat tauopathies), reasonable pharmacokinetic characteristics, minimal DDI potential, lack/minimal effects on cardiovascular, pulmonary and CNS systems, and a lack of genotoxicity. Relatively modest, non-adverse toxicity was observed in 28-day rat and dog GLP toxicity studies. The no adverse effect level for both the rat and dog 28 day studies were the highest dose tested. Thus, TO- 0582 is an excellent candidate for clinical development for treatment of neurodegenerative diseases. Manufacture of kilogram quantities for non-clinical safety studies (NCSS) and drug pre-formulation work has been completed. A GMP batch was also prepared for the manufacture of our drug product OLX-07010. We are preparing our electronic IND application for our phase 1a study that will be submitted to FDA by mid-April 2022 and anticipate first-in-human studies will begin in June of 2022. The Aims of the proposed program are: Aim 1 Perform 26-weeks oral toxicity study (GLP) in Rats with a four-week recovery period (GLP). This includes scaling up the manufacture of TO-0582 to 5 kg level. Aim 2: Conduct a therapeutic therapeutic efficacy study in TAPP mice; and Aim 3: Conduct an acute therapeutic efficacy study TAPP mice. The second and third Aims will evaluate biomarkers that could translate into the planned Phase 1b clinical AD study and to show efficacy of the compound in a mouse model with tau and amyloid beta pathology, acute and chronic dosing studies will be performed in the tau-APP (TAPP) mice which will support transition of clinical work from healthy volu...