Development of Novel Tricyclic Pyrone Drugs for Treatment of Alzheimer's Disease Alzheimer's disease (AD) afflicts approximately 35 million people worldwide and is the most common cause of dementia in the elderly. There is an unmet medical need for new AD therapeutic development. Amyloid-b (Ab) deposited in AD brains has been hypothesized to initiate a cascade of molecular changes leading to synaptic dysfunction, inflammation, and neuronal death observed in AD brains. Therefore, designing therapies targeting Ab and downstream events have become a major effort in AD drug development. We have taken the rational design approach and synthesized a class of tricyclic pyrone compounds (TPs). The lead compounds CP2 and TP70 were found to have high oral bioavailability, excellent blood-brain barrier permeability, and low toxicity. Administering compounds either orally or intraperitoneally to young AD transgenic models in 'preventive studies'resulted in substantially reduced soluble and insoluble Ab species in the brain and preserved memory and motor function. Furthermore, we have found that in addition to being able to block the toxicity and formation of both intraneuronal and extracellular A? aggregates, the lead TPs also increase cellular cholesterol efflux, restore axonal trafficking, and enhance hippocampal synaptic placidity - these synergistic cellular actions could be potential mechanisms underlying in vivo effects. The discovery of these lead TP compounds comes from the collaboration among Dr. Hua, a medicinal chemist, Dr. Jin, an AD neuropathology expert, and recently the PI Dr. Xie, who has substantial experience in pharmaceuticals and contributed to drug development in the CNS therapeutic area. Dr. Xie at AfaSci started with developing the SmartCageTM system and then has taken advantage of the technology in translational research. In the proposed project with the support of this phase I SBIR, we will thoroughly study pharmacokinetics (PK) and in vivo pharmacodynamics (PD) of the lead TPs, through accomplishment of the following Specific Aims: 1. Focus on two novel lead compounds CP2 and TP70 in the therapeutic studies: We will generate PK/PD and ADME (absorption, distribution, metabolism, and excretion) profiles of lead compounds. We will focus on investigating the in vivo efficacy (neurobehavioral and neuropathological outcomes) of lead compounds by oral administration to the AD model APP/PS1 mice. These studies will provide evidence-based selection of a therapeutic candidate using the criteria of druggable PK profile, in vivo efficacy especially in cognition, and improved pathologic outcomes. 2. Utilization of novel lead compounds LRL22 and LRL50 as backup compounds, if needed, and preparation for good manufacturing practice (GMP) production of the selected therapeutic candidate. Although we have identified five top backup TP compounds, we will use our previously discovered novel leads LRL22 and LRL50 which possess different chemical structures from TP, but also shown inhibition of Ab-induced toxicity and neuroprotection as backup compounds. The backup compounds will be re-synthesized and ready to be tested in vivo as described in Aim 1, should both CP2 and TP70 not fulfill the criteria of therapeutic candidates. We will also optimize the chemical synthesis process in preparation for GMP production of the identified therapeutic candidate for a Phase II study. Success in the Phase I study will prepare for investigational new drug (IND)-enabling studies in a Phase II project. Our ultimate goal is to translate our preclinical discovery of the novel TP compounds into clinical therapeutic candidates that possess AD disease-modifying properties.
Alzheimer's disease (AD) is the major cause of dementia and one of the most disabling health conditions worldwide. Current drugs only have modest effects and there is an unmet need to develop more effective and safer medicines for the treatment of AD. We here propose to study two novel tricyclic pyrone compounds that show potent cell protective action against Ab toxicity for their potential to treat cognitive impairment and slow disease progression in an animalmodel of AD.
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