Drug Rescue

VistaGen’s stem cell technology platform is based on proprietary and licensed technologies for controlling the differentiation of human pluripotent stem cells (hPSCs) and producing the multiple types of mature, non-transformed, functional, adult human cells that we use, or plan to use, to reproduce complex human biology and disease and assess, in vitro, the potential therapeutic benefits and safety risks of new chemical entities (NCEs). 

We used our hPSC-derived cardiomyocytes (human heart cells) in CardioSafe 3D™, our novel, customized in vitro bioassay system for predicting potential cardiotoxicity of drug rescue NCEs. We believe CardioSafe 3D is more comprehensive and clinically predictive than the hERG assay, currently the only in vitro cardiac safety assay required by FDA guidelines, and that CardioSafe 3D offers us a new paradigm for evaluating and predicting potential heart toxicity of drug rescue NCEs early in development, long before costly, high risk human clinical trials.

 

 

Medicinal Chemistry

Medicinal chemistry involves designing, synthesizing, or modifying a small molecule compound or drug suitable for clinical development. It is a highly interdisciplinary science combining organic chemistry, biochemistry, physical chemistry, computational chemistry, pharmacology, and statistics. The combination of medicinal chemistry with the proprietary and licensed hPSC technologies underlying our stem cell technology platform are core components of our drug rescue business model.

Using Stem Cell Technology to Produce and Develop Drug Rescue NCEs

Our drug rescue activities are focused on producing, for our internal pipeline, proprietary, safer variants of still-promising NCEs previously discovered, optimized and tested for efficacy by pharmaceutical companies and others but terminated before FDA approval due to unexpected heart toxicity. Our current drug rescue strategy involves using CardioSafe 3D to assess the toxicity that caused certain NCEs available in the public to be terminated, and use that biological insight to produce and develop a new, potentially safer, and proprietary NCEs for our pipeline. We believe the pre-existing public domain knowledge base supporting the therapeutic and commercial potential of NCEs we target for our drug rescue programs will provide us with a valuable head start as we launch each of our drug rescue programs. Leveraging the substantial prior investments by global pharmaceutical companies and others in discovery, optimization and efficacy validation of the NCEs we identify in the public domain is an essential component of our drug rescue strategy. 

By using CardioSafe 3D to enhance our understanding of the cardiac liability profile of  NCEs, biological insight not previously available when the NCEs were originally discovered, optimized for efficacy and developed, we believe we can demonstrate preclinical proof-of-concept (POC) as to the efficacy and safety of new, safer drug rescue NCEs in standard in vitro and in vivo models, as well as in CardioSafe 3D, earlier in development and with substantially less investment in discovery and preclinical development than was required of pharmaceutical companies and others prior to their decision to terminate the original NCE.  

Our goal in each drug rescue program will be to produce a proprietary drug rescue NCE and establish its preclinical POC, using standard preclinical in vitro and in vivo efficacy and safety models, as well as CardioSafe 3D. In this context, POC means that the lead drug rescue NCE, as compared to the original, previously-terminated NCE, demonstrates both (i) equal or superior efficacy in the same, or a similar, in vitro and in vivo preclinical efficacy models used by the initial developer of the previously-terminated NCE before it was terminated for safety reasons, and (ii) significant reduction of concentration dependent cardiotoxicity in CardioSafe 3D.

Strategic Development and Commercialization of Drug Rescue NCEs

Once we optimize a patentable drug rescue NCE, we intend to develop it internally to establish preclinical POC in established in vitro and in vivo efficacy and safety models, as well as in CardioSafe 3D. After we establish preclinical POC of a patentable drug rescue NCE, we will decide between continuing to develop it internally and out-licensing it to a pharmaceutical company. If we license it to the pharmaceutical company, it will be responsible for all subsequent development, manufacturing, regulatory approval, marketing and sale of the drug rescue NCE and we will generate revenue through payments to us from the license upon signing the license agreement, achievement of development and regulatory milestones, and, if approved and marketed, upon commercial sales, although no assurances can be given that we will seek and complete a partnership, or that the terms of such a beneficial arrangement will be available or offered to us.