Chemo-Sero-Therapeutic Research Institute Release: Preclinical Studies Provide Additional Safety And Efficacy Evidence For VaxGen, Inc.'s Smallpox Vaccine Candidate

Published: Nov 28, 2005

BRISBANE, Calif., Nov. 28 /PRNewswire/ -- Data from a series of preclinical studies presented by the Chemo-Sero Therapeutic Research Institute (KAKETSUKEN) at the 53rd Annual Conference of the Japanese Society of Virology provided additional evidence of the safety and efficacy of an attenuated smallpox vaccine being developed by VaxGen, Inc. . The attenuation refers to a genetic modification that is intended to improve the vaccine's safety.

(Logo: )

The purpose of the studies was to compare the safety of VaxGen's attenuated vaccine candidate, LC16m8, with that of the unattenuated Lister strain of vaccinia. Lister vaccine, the parent strain from which LC16m8 is derived, was used in the World Health Organization's successful smallpox eradication program. A separate preclinical study also examined the efficacy of LC16m8.

"Results from these studies continue to support our belief that LC16m8 could provide a safer, yet effective alternative to conventional smallpox vaccines," said Marc Gurwith, M.D., VaxGen's Senior Vice President, Medical Affairs and Chief Medical Officer.

Data from separate preclinical studies designed to assess the safety of the vaccine candidate provided the following results:

-- In a study of Severe Combined Immune Deficient (SCID) mice, a model for the compromised immune system, all mice that received Lister died while all mice that received LC16m8 survived as of 28 days after vaccination (p=0.002). The mean survival time for mice that received Lister was 14 days. -- A much higher concentration of LC16m8 than Lister vaccine virus was required to cause erythema, or skin irritation/redness (p=0.002), indicating that LC16m8 may be better tolerated at the vaccination site. -- LC16m8 was less likely than Lister vaccine to cause neurovirulence, i.e., infection or inflammation of the central nervous system, in both adult and suckling mouse models. In the adult mice, 67% of mice that received Lister died while all animals that received LC16m8 survived. In suckling mice, those that received LC16m8 survived nearly three times as long as those that received the Lister vaccine (p=0.001).

In addition, a study to assess the efficacy of LC16m8 was performed. Groups of mice were vaccinated with varying doses of LC16m8 and were then challenged intranasally with the Western Reserve strain of vaccinia (a relative of the smallpox virus). All mice receiving LC16m8 were completely protected, while all control mice died.

A copy of the poster, "Safety Evaluation of Dried Smallpox Vaccine in Cell Culture," is available through the company's web site at: .

About LC16m8

VaxGen is developing LC16m8 for the U.S. and elsewhere in partnership with KAKETSUKEN in Kumamoto, Japan. LC16m8 was initially developed in Japan to address the need for a smallpox vaccine that was safer than but as effective as conventional, unattenuated smallpox vaccines. Serious side effects from conventional, unattenuated smallpox vaccines currently stockpiled make them inappropriate for use prior to an outbreak. LC16m8 was licensed in Japan in 1980 as the only attenuated single-dose vaccine approved for the prevention of smallpox.

A clinical evaluation of LC16m8 in over 50,000 children in Japan during the 1970s showed no major differences in immunogenicity compared to conventional smallpox vaccines, including Lister. A recent Phase I/II clinical study of LC16m8 in humans the United States demonstrated a strong safety profile with no serious adverse events related to the vaccine candidate.

About VaxGen

VaxGen, Inc. is a biopharmaceutical company engaged in the development, manufacture and commercialization of biologic products for the prevention and treatment of human infectious diseases, including anthrax, smallpox and Meningitis B. The company has been awarded an $877.5 million U.S. government contract to provide 75 million doses of its recombinant anthrax vaccine for civilian biodefense. Based in Brisbane, Calif., VaxGen operates a wholly owned manufacturing facility in California and owns 22% of Celltrion, Inc., a South Korean operation established to provide contract manufacturing to the global pharmaceutical industry. For more information, please visit the company's web site at: .


KAKETSUKEN is a Juridical Foundation which researches, develops, manufactures and supplies biological products such as vaccines for humans and animals, and blood plasma derivatives. Based in Kumamoto, Japan, the foundation has pursued the preventive medicine fields of microbiology, immunology and serology, towards the improvement of health and hygiene, and is a leading company in the fields of human vaccines, animal vaccines, and blood plasma derivatives respectively in Japan. For further information about KAKETSUKEN, please visit the company's web site at .

NOTE: This press release contains "forward-looking statements" within the meaning of the federal securities laws. These forward-looking statements include without limitation, statements regarding the potential safety and efficacy of LC16m8. These statements are subject to risks and uncertainties that could cause actual results and events to differ materially from those anticipated. Reference should be made to the Risk Factors listed in VaxGen's Current Report on Form 8-K filed with the Securities and Exchange Commission on March 31, 2005 for a more detailed description of such risks. Readers are cautioned not to place undue reliance on these forward-looking statements that speak only as of the date of this release. VaxGen undertakes no obligation to update publicly any forward-looking statements to reflect new information, events, or circumstances after the date of this release except as required.

Photo: NewsCom: Archive: http://photoarchive.ap.orgPRN Photo Desk,photodesk@prnewswire.comVaxGen, Inc.

CONTACT: Lance Ignon, Vice President, Corporate Affairs, +1-650-624-1016;or Kesinee Angkustsiri Yip, Associate Director, Corporate Affairs,+1-650-624-2304, both of VaxGen

Back to news