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CytoDyn DNA Vaccine Shows Promise for Low-Dose Protection from Bird Flu, Reliable Supply

SANTA FE, N.M.--(BUSINESS WIRE)--Aug 8, 2007 - CytoDyn, Inc. (PINK SHEETS: CYDY) has completed analysis of its prospective, placebo-controlled study that used mice to compare nine variations of experimental DNA vaccines for the bird flu. Mice are the standard animal model for pre-clinical studies of human flu vaccines. Three of the vaccines given at a relatively low dose caused mice to develop antibodies against the bird flu (H2 subunit of HA H5) at a significant level (detectable at a dilution of 1:12,500). The three vaccines were:

1. The vaccine that the Company obtained from the University of Massachusetts Medical School (UMMS).

2. A vaccine based on the UMMS product that the Company had enhanced using the latest method of improving DNA vaccines (CpG motif).

3. A similarly enhanced bird flu vaccine from a company that makes DNA vaccines for protecting animals.

All three appeared to be equally effective in terms of the quantity of antibodies produced, although, without enhancement, the UMMS vaccine appeared to be somewhat less potent in other respects. However, vaccines based on the UMMS product, including the Company's enhanced vaccine, appear to work faster (because of a codon optimized Vietnam 1203 HA gene). Faster action could be an advantage because public health officials are unlikely to vaccinate large populations against the bird flu before a pandemic of bird flu has actually broken out. Once a pandemic has started, there will be a need to protect the human population as quickly as possible.

These results are only preliminary but will guide market strategy for the Company's vaccine, according to CEO Allen D. Allen. He will be discussing vaccine markets on a live webcast scheduled for August 10, 2007 at 12:30 PM EST on Market News First.

Competition or Collaboration?

Much fanfare has surrounded the gene gun being developed by PowderMed, a wholly owned subsidiary of Pfizer (NYSE: PFE). The gene gun is used to deliver a DNA vaccine for bird flu directly into human cells thereby increasing potency, albeit at the expense of creating massive new inventories of the device to replace the ubiquitous hypodermic. PowderMed's DNA vaccine is reported to be an older version of the UMMS vaccine without enhancement. Consequently, successful development of CytoDyn's more effective DNA vaccine could provide PowderMed with a means of competing against the traditional vaccines under development at major pharmaceutical companies since these may be sufficiently potent for administration with a hypodermic.

One such vaccine was recently licensed by the FDA for marketing by Sanofi-Avantis (NYSE: SNY) but only protected 45% of those vaccinated in clinical trials. On the other hand, GlaxoSmithKline (NYSE: GSK) reports a proprietary adjuvant that protected 80% of subjects in preliminary clinical trials. (An adjuvant is a chemical that stimulates the immune system and can make vaccines work better.) Likewise, BioSante (AMEX: BPA) found that its adjuvant doubled the potency of bird flu vaccines in mice. It is likely that all flu vaccines will eventually use an adjuvant to make them more potent. None will have the advantages of a potent DNA vaccine. But the two types of vaccines could be used together to provide the best option of all.

Animal studies conducted by UMMS have shown that DNA vaccines and traditional vaccines could be used together to reinforce each other with the proprietary version of "prime/boost" licensed exclusively to CytoDyn by UMMS. Prime/boost more generally refers to administering a DNA vaccine, waiting for an appropriate amount of time to elapse, and then boosting the vaccine with a protein. Consequently, CytoDyn's product could wind up being used in conjunction with traditional bird flu vaccines, as opposed to being a competing product.

About DNA Vaccines

There are several advantages to DNA vaccines because they are engineered in the laboratory and do not contain viruses that require strict manufacturing, transportation, and storage conditions like traditional vaccines. Anthony S. Fauci, M.D, Director of the National Institute of Allergies and Infectious Diseases (NIAID) said, "More broadly, development of this (bird flu) DNA vaccine technology has the potential to improve our production capacity for vaccines to prevent seasonal influenza and other diseases."

Several DNA vaccines have been developed that protect avian species and some mammals other than humans. The challenge has been to develop DNA vaccines that protect humans as effectively as they protect animals. A potential path for making progress in this regard is to reach beyond the traditional goal of creating antibodies to include the cell-mediated immune response as well. The NIAID tried this while developing an experimental DNA vaccine that protects mice from the virus that caused the flu pandemic of 1918, albeit with antibodies alone, and the CDC has encouraged such research. The latest approach uses a recent discovery about the immune system known as CpG motif. In CytoDyn's study, this enhancement increased cell-mediated immunity 4-fold in mice. However, the more apparent effect was to stimulate B cells, the cells of the immune system that make antibodies.


This press release contains forward-looking statements that are not historical facts. The Company's management makes forward-looking statements concerning the Company's expected future operations, performance and other developments. These forward-looking statements are necessarily estimates based upon current information and involve a number of risks and uncertainties, including but not limited to, the failure of preliminary results from scientific studies to reflect the results from more comprehensive studies. There can be no assurance that such risks and uncertainties, or other factors, will not affect the accuracy of such forward-looking statements. It is impossible to identify all factors that could cause actual results to differ materially from those estimated by the Company. They include, but are not limited to, government regulation, managing and maintaining growth, victimization by white-collar offenders, and the effects of adverse publicity, litigation, competition, and other factors that may be identified from time to time in the Company's announcements.


CytoDyn, Inc.
Stacia Andrews, 505-988-5520
Corinne Allen, 505-988-5520

Posted: August 2007