July 19, 2012 -- VistaGen Therapeutics is a biotechnology company focused primarily on the use of its proprietary pluripotent stem cell technology to discover, rescue, and develop novel drug candidates for a wide range of diseases. For those unfamiliar with stem cells, pluripotent stem cells can differentiate into almost any of the over 200 types of cell in the human body.
VistaGen’s drug rescue initiatives involve the combination of its human pluripotent stem cell technology with modern medicinal chemistry as practiced by major pharmaceutical companies. VistaGen’s drug rescue goal is to build on substantial prior investment by major pharmaceutical companies to generate new chemical variants of once-promising small molecule drug candidates that the pharmaceutical companies have put on hold during preclinical or early clinical trials due to heart or liver toxicity. In other words, the drug candidates were effective but had some toxic side effects.
VistaGen’s pluripotent stem cell technology platform, Human Clinical Trials in a Test Tube, is based on carefully controlled differentiation of human pluripotent stem cells into multiple types of highly functional, mature human cells which then can be used in new generation bioassay systems for superior predictive toxicology testing, enabling better, more efficient drug rescue and development decision making. VistaGen’s Human Clinical Trials in a Test Tube platform performs its check for toxicity with much greater flexibility, speed, and precision than other in vitro assay systems and animal testing currently in use by the pharmaceutical industry.
With mature human heart cells produced from pluripotent stem cells, VistaGen Therapeutics has developed CardioSafe 3D, a three-dimensional bioassay system. The company believes this system is capable of predicting the in vivo cardio effects (toxic or not) of small molecule drug candidates long before the drug candidates are actually tested in animals or humans. VistaGen also is developing and validating a similar system for assessing liver toxicity and metabolism called LiverSafe 3D.
In parallel with its drug rescue activities, VistaGen Therapeutics also is looking to advance its pilot nonclinical development of cell therapy programs focused on blood, heart, liver, pancreas, and cartilage cells. Each of these programs will be based on the capabilities of its platform, Human Clinical Trials in a Test Tube.
In addition, thanks to $8.9 million in funding from the U.S. National Institute of Health to date, the company is developing AV-101, an orally available small molecule drug candidate aimed at the multi-billion dollar market for neurological diseases. AV-101 is currently in Phase Ib trials in the U.S. for the treatment of neuropathic pain, a serious and chronic condition affecting approximately 1.8 million people in the United States, causing pain after injury or disease of the nervous system.
The company’s strategy for the future is to develop, in collaboration with its “ecosystem” of contract drug development service partners, a pipeline of drug rescue variants - proprietary new small molecule drug candidates - that will be effective as the original drug candidates but without the toxicity that caused pharmaceutical companies to put them on the shelf.
Initially, the company plans to execute its drug rescue strategy through the use of the vast amount of information in the public domain to identify and assess potential drug rescue candidates. Then, if necessary, it may acquire the rights for some of the most promising drugs from a number of other sources, usually pharmaceutical companies. With respect to each and every drug rescue variant it produces, VistaGen plans to have economic participation rights, including development milestone and royalty payments, which should benefit its bottom line as well as its shareholders.
Key to VistaGen’s strategy and importance in the marketplace is the fact that the U.S. pharmaceutical industry is facing a drug discovery and development crisis. Over the past decade, the U.S. Food and Drug Administration has approved an average of only about 24 novel drugs per year, a modest number relative to the truly staggering amount invested each year by the industry for drug development. VistaGen believes this annual phenomenon - high cost of drug development/low number of new drug approvals - is caused, at least in part, by the remarkably high cost of failure associated with unexpected heart and/or liver toxicity during development. Such unexpected toxicity often results from limitations inherent in the major toxicological testing systems currently being used in the pharmaceutical industry, specifically animal testing and cellular assays based on transformed cell lines or human cadaver cells.
Conventional animal and in vitro testing can, at best, only approximate human biology. A pharmaceutical company can spend millions of dollars on a promising lead drug candidate, taking it through nonclinical development, only to see it fail due to unexpected heart or liver toxicity. The pharmaceutical company then often discontinues the development program for the once-promising drug candidate, despite the positive efficacy data indicating its potential therapeutic and commercial benefits. As a result, the pharmaceutical company’s significant prior investment may be lost. It’s a serious problem, since it has been estimated that at least one-third of all potential new drug candidates fail due to safety concerns.
Since the total cost of developing a drug can now easily exceed $1 billion, and considering how much of this can be lost when a drug has to be pulled due to unexpected heart or liver toxicity, superior stem cell-based in vitro testing could save the pharmaceutical industry untold amounts of money, while helping ensure safer drugs get to market. Applying the clinically predictive capabilities of CardioSafe 3D™ and, eventually, LiverSafe 3D™, in conjunction with medicinal chemistry, VistaGen believes it can generate novel, proprietary, safer drug rescue variants of once-promising drug candidates originally discovered and developed by pharmaceutical companies, thereby “rescuing” their substantial investment in prior research, discovery, and development. The FDA has noted that even a 10% improvement in predicting the failure of a drug candidate due to toxicity before it enters clinical trials could, when averaged over a pharmaceutical company’s drug development efforts, avoid $100 million in development costs per marketed drug.
By differentiating pluripotent stem cells into mature, functional human cells that can then be used as the basis for customized in vitro toxicology screening bioassay systems, VistaGen has the potential to identify human toxicity of drug candidates early in the drug development process, resulting in efficient focusing of resources on those candidates with the highest probability of success. The company is convinced that this has the potential to substantially reduce development costs while enabling development of safer and more effective drugs, and represents a major market opportunity.
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