ALBUQUERQUE, N.M., March 20, 2006 (PRIMEZONE) -- A recent meeting of the New Mexico Biotechnology & Biomedical Association featured a talk by Allen D. Allen, CEO of CytoDyn, Inc. (OTCBB:CYDY). According to Allen, the human species is locked in an unending cat-and-mouse game with its microscopic predators. New types of drugs to fight infections must be continually invented as germs evolve through natural selection to become resistant to whatever drugs are currently available. Dr. Tim Johnson, Medical Editor for ABC News, put it concisely when he said, "These bugs have a remarkable ability to mutate and develop resistance to whatever we throw at them." You can read more about this by copying and pasting the URL below into your browser.
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As a contemporary example, Allen cites two drugs previously used to treat the flu (influenza): Symmetrel(R), marketed by Endo Pharmaceuticals (Nasdaq:ENDS), and Flumadine(R), marketed by Forest Laboratories (NYSE:FRX). These two drugs are ineffective against H3N2 influenza, the dominant strain for this season, according to the CDC. However, two other drugs are still effective, Tamiflu(R), marketed by Roche (XETRA:RHO.DE) and Relenza, marketed by GlaxcoSmithKline (NYSE:GSK).
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After the latter two drugs have been used for a sufficient number of years, the surviving influenza virus will be resistant to those drugs and new ones will again be needed.
The Infectious Diseases Society of America (www.idsociety.org) has a list of "Bad Bugs Without Drugs," meaning bacteria that have become resistant to the drugs traditionally used to treat them. The greatest concern is focused on Methicillin-Resistant Staphylococcus aureus (MRSA). This life threatening germ was previously limited to nosocomial infections; that is, infections that occur in a hospital. Nosocomial infections are difficult to treat because germs and drugs are geographically concentrated in hospitals. This concentration accelerates the evolution of drug-resistant germs through natural selection. Recently, however, MRSA has begun to appear in the community posing a new threat to the public health.
Allen points out that the problem of creating drug-resistant germs can be avoided when treatments use the immune system to control an infection rather than attacking the germ directly. The oldest example of this is vaccines, which prepare the immune system to fight a germ. The only epidemics that were ever truly conquered by medical intervention, such as small pox and infantile paralysis, were eliminated by vaccines.
A more recent example is the use of interferon-alpha to treat serum hepatitis. This is an example of an "immunologically-mediated infectious disease," meaning a disease that is triggered by a virus but in which the immune system contributes to the disease. The immune systems of individuals infected with hepatitis B or C virus attack the liver with cytotoxic T lymphocytes (CTL). Interferon-alpha removes a substance from the surface of the liver that provides a target for the CTL, thereby preventing these cells from binding to the liver and causing damage. Likewise, Cytolin(R), one of the products in the pipeline of CytoDyn, protects CD4+ T cells from being indiscriminately destroyed by CTL in individuals infected with HIV. In preliminary human trials, there was an exact correlation between the rebound of CD4+ T cells and a marked reduction in viral burden.