Memantine, an aminoadamantane, is approved to treat moderate-to-severe Alzheimer's disease in the US and in Europe. Memantine selectively inhibits abnormally active N-methyl-D-aspartate-type glutamate receptor (NMDAR) channels, while preserving normal glutamate activity and physiological neuronal function (Lipton, 2006;Lipton, 2007a,b). Pathological NMDA receptor activity is further down-regulated by Snitrosylation of cysteine residues located on the N-terminus or extracellular domain. Taking advantage of these insights, PRI has developed a proprietary series of bifunctional antagonists, called nitromemantines, that not only preferentially bind to the open-channel state but also selectively target NO to a second modulatory site using the memantine pharmacophore as a homing motif (Wang, 2006, Wang et al. patents). Our data suggest that some of these memantine analogs have good potency, while maintaining selectivity for persistently open NMDAR channels. Most importantly, they appear to have greater neuroprotective properties than memantine in both in vitro and in vivo animal models. Recent work from the laboratory of our collaborator and co-inventor, Professor Stuart Lipton (Burnham Institute) demonstrates the unique ability of one of our nitromemantines (YQW-036, 1-amino-3,5-diethyl-7-nitrateadamantane) to rescue/protect synapses perhaps by superior inhibition of pathogenic extrasynaptic NMDARs (Talantova, 2013) This animal POC combined with the demonstrated safety of nitromemantines support the translation of this basic science work into clinical stage evaluation. Hence, our overall goal is to initiate preclinical studies to support submission of an IND for YQW-036. This effort will begin with Phase I pharmacokinetics and safety studies of YQW-036 as a potential development candidate. Successful completion of the Phase I studies will merit submission of a Phase II application to support IND enabling studies that are required prior to human clinical trials. Successful achievement of these milestones will provide a proprietary first-in-class disease-modifying drug for Alzheimer's disease.
Alzheimer's disease (AD) is a devastating form of dementia with an increasing incidence due to our aging population. The FDA-approved drug memantine is arguably the best available therapeutic for AD. We have synthesized an improved memantine-like drug (nitromemantine) and have demonstrated its effectiveness in in vitro and in an animal model of AD. Development of nitromemantine will result in a novel and potentially disease-modifying treatment for AD.
