Exhibit 99.1
VaxGen Reports Phase I Clinical Trial Results of Anthrax
Vaccine Candidate
BRISBANE, Calif. - March 2, 2004 - VaxGen, Inc. (Nasdaq: VXGN) today
announced results of its Phase I trial of recombinant Protective Antigen anthrax
vaccine, rPA102, at the International Conference on Emerging Infectious Diseases
(ICEID) in Atlanta, Georgia. The double-blind, multi-center study, which began
in June 2003, was designed to examine the safety and immune response of a range
of doses of rPA102, and to compare them to Anthrax Vaccine Adsorbed (AVA), the
anthrax vaccine currently licensed for use in the United States.
In a presentation titled "Ascending Dose Safety and Immunogenicity Study
of a Recombinant Protective Antigen (PA) Anthrax Vaccine (rPA102) [Slide Session
No. 57](1)," researchers demonstrated that the immune responses to VaxGen's
rPA102 at the higher doses (50 ug and 75 ug) were comparable to that of AVA,
despite a 10-fold greater amount of aluminum adjuvant, an immune stimulant,
in AVA.
There was a clear relationship between the amount of rPA102 administered
and the subsequent immune response, with antibody titers continuing to increase
after the second and third administration of the vaccine candidate at each dose
level. rPA102 was well-tolerated, with no evidence of dose-limiting toxicity or
reactogenicity at any dose. Harry L. Keyserling, M.D., Professor of Pediatrics,
Emory University School of Medicine, along with colleagues at St. Louis
University Health Sciences Center, Johns Hopkins University Bloomberg School of
Public Health, Baylor College of Medicine and VaxGen, conducted the research
presented at ICEID.
"Despite formulations that had a tenth of the adjuvant content, antibody
responses at the higher dose levels of rPA102 were within the same range as
those associated with AVA," said Dr. Keyserling, one of four principal
investigators for the study. "We are encouraged to find that increasing
concentrations of rPA102 elicited a greater immune response with no significant
increase in reactions. It is also noteworthy that other recent studies
demonstrated that animals given similar doses of rPA102 were protected against
an aerosol challenge with anthrax spores."
The Phase I study was funded by VaxGen's contract N01-AI-25494 with the
National Institute of Allergy and Infectious Diseases (NIAID), a component of
the National Institutes of Health (NIH). VaxGen plans to launch two Phase II
trials of rPA102 this year, supported by separate NIAID funding, under contract
N01-A1-30053. The first Phase II trial, scheduled to begin this month, is
designed to determine the optimal concentrations of aluminum adjuvant and
recombinant Protective Antigen (rPA) to induce an even greater immune response.
(rPA is a
- --------
(1) Keyserling HL, Gorse GJ, Keitel W, et al. Ascending dose safety and
immunogenicity study of a recombinant protective antigen (PA) anthrax vaccine
(rPA102). The International Conference on Emerging Infectious Diseases (ICEID),
February-March 2004. Slide Session No. 57.
purified protein designed to induce antibodies that neutralize anthrax toxins.)
A second Phase II trial, scheduled for later this year, is designed to determine
the optimal dosing schedule of rPA102 for use before and after exposure to
anthrax.
"We look forward to advancing the development of rPA102 and to the
potential opportunity to supply this strategically important vaccine to the U.S.
and other approved governments and private customers," said Lance K. Gordon,
Ph.D., VaxGen's chief executive officer.
About the Phase I Clinical Trial of rPA102
The Phase I study was designed to evaluate the safety and immunogenicity
of escalating doses of rPA102. The doses of rPA were escalated from 5 ug through
75 ug, and all doses were formulated with a standard amount of adjuvant (82.5 ug
aluminum hydroxide). AVA, which served as a comparator in this trial, contains
variable amounts of PA protein, as well as other components, adsorbed to 830 ug
of aluminum adjuvant. One of four different rPA102 vaccine formulations (5, 25,
50, or 75 ug), or the AVA control, was administered to a total of 100 healthy
adults, ages 18 to 40 years, at 4-week intervals.
Local reactions, mostly arm pain, were more common with the AVA vaccine as
compared to rPA102 (89.5% vs. 34.4%, p=0.003), whereas short-lived systemic
reactions, mostly mild headache and fatigue, were more common with rPA102 (39%
vs. 18%, p<0.001). Both AVA and rPA102 induced an immune response, with
immunologic responses to rPA showing a clear dose-response relationship.
Antibody levels continued to increase after the third injection of rPA102.
About rPA102
VaxGen's rPA102 is based on work conducted at the U.S. Army Medical
Research Institute of Infectious Diseases. The vaccine combines the potential
safety benefits of a product made through modern recombinant technology with
efficacy demonstrated in animal models. The vaccine candidate cannot cause
anthrax infection.
VaxGen began developing rPA102 to address the need for an anthrax vaccine
with an improved safety profile and a more practical dosing schedule compared to
AVA. The approved dosing regimen for AVA requires six doses administered over an
18-month period. VaxGen's rPA102 is required to provide immunity with no more
than three doses.
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. Based in Brisbane, Calif., the company
is developing preventive vaccines against anthrax, smallpox and plague and an
anthrax monoclonal antibody through an alliance with Avanir Pharmaceuticals.
VaxGen also is the largest shareholder in Celltrion, Inc., a joint venture
formed to build operations for the manufacture of biopharmaceutical products,
including
VaxGen's product candidates. For more information, please visit the company's
web site at: www.vaxgen.com.
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 timing, progress and results of
VaxGen's clinical development of rPA102, the ultimate safety and efficacy of
rPA102 and VaxGen's ability or intentions to sell the vaccine. 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
Item 5 of the first Current Report on Form 8-K filed by VaxGen on December 2,
2003, under the headings "Risk Factors" and "Business" for a more detailed
description of such factors. 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 by law.
Media Contact:
Kesinee Angkustsiri Yip
Associate Director, Corporate Communications
Mobile: 650-238-4685 (at ICEID 3/1/04-3/3/04)
Office: 650-624-2304
kyip@vaxgen.com
Investor Contact:
Lance Ignon
Vice President, Corporate Communications
650-624-1041
lignon@vaxgen.com