HIV Vaccine Candidates from Merck and Aventis Used Together
Generate Encouraging Anti-HIV Immune Response in Monkeys
Companies to Collaborate on Early Human Testing This Year
LYON, FRANCE AND WHITEHOUSE STATION, N.J., USA, March 27, 2003 - A
combination of two anti-HIV-1 vaccine candidates developed by Aventis
Pasteur, a subsidiary of Aventis, and Merck & Co., Inc., elicited levels of a
cellular immune response against HIV-1 infection in monkeys that were higher
than the levels observed in the vaccine candidates separately, leading
scientists from both companies to plan a joint human study that will begin
later this year.
The pre-clinical findings in monkeys provide an early indication that the
vaccine candidates used together in a complementary way, known as a
prime-boost regimen, may be able to stimulate higher-level immune responses
against HIV-1 than either vaccine used separately. Researchers for Merck and
Aventis Pasteur say the Phase I clinical trial, which will be conducted in
the U.S., will provide preliminary data about whether the combination of the
two vaccine candidates can produce similar encouraging results in humans.
Phase I represents the earliest stage of human testing for a potential
In studies conducted in rhesus macaque monkeys, a prime-boost regimen
with Merck's replication-defective adenovirus type 5 vector (Ad5) vaccine
candidate given first, and Aventis Pasteur's canarypox virus vector (ALVAC)
vaccine candidate given afterward, stimulated levels of cellular immune
responses against HIV-1 that were higher than levels seen using the Ad5
vector alone, according to Emilio A. Emini, Ph.D., senior vice president of
Vaccine Research at Merck. Dr. Emini will report the results of the
pre-clinical studies at the Keystone Conference on HIV Vaccine Development,
an annual gathering of leading HIV vaccine researchers in Banff, Canada on
Details of the Pre-clinical Findings
Scientists evaluated vaccine-elicited cellular immune responses in the
monkeys using the two vaccine candidates, both of which expressed the HIV-1
gag protein. Monkeys were vaccinated with the Ad5 vector and then
subsequently boosted with Ad5 vector again or, alternatively, with the ALVAC
vector. Use of the two different vectors resulted in immune responses that
were superior to those seen using just the Ad5 vector alone. Specifically,
the superior results were obtained when the Ad5 vector was used as the
priming (first dose) vaccine and the ALVAC vector was used as the booster
The findings, according to Merck and Aventis Pasteur scientists, were
compelling enough to merit further study. "The results from the pre-clinical
immunogenicity data in monkeys are encouraging," Dr. Emini said. "It is our
hope that this collaboration may help speed development and access to new
Michel DeWilde, Ph.D., executive vice president of Research and
Development at Aventis Pasteur, the vaccines business of Aventis, joined Dr.
Emini in characterizing the collaboration. "We are extremely encouraged by
the pre-clinical data and are moving to the clinic quickly," Dr. Dewilde
said. "This is an unprecedented pairing between two companies with large,
established HIV vaccine research programs. We hope that this collaboration
will contribute to a solution to this devastating epidemic."
Merck, whose HIV vaccine research program has been ongoing for almost 20
years, first began testing its HIV vaccine candidates in humans in late 1999.
The MRKAd5 HIV-1 gag vaccine candidate is based on a modified common cold
virus that is used as a means of delivering an HIV gene called gag into the
cells to produce a potent cellular immune response to HIV.
In addition to the work being conducted as part of the collaboration with
Aventis Pasteur, Merck is continuing its ongoing, independent research to
develop an HIV vaccine. Phase I trials are underway in about half of U.S.
states and the District of Columbia. About 1,300 uninfected and HIV-infected
volunteers are participating in the studies, which are taking place at about
70 clinical sites. Later this year, Merck plans to begin the first
international trial of its leading HIV vaccine candidate in conjunction with
another organization, the National Institute of Allergy and Infectious
Diseases (NIAID)-sponsored HIV Vaccine Trials Network (HVTN).
Merck & Co., Inc. is a global research-driven pharmaceutical products and
services company. Merck discovers, develops, manufactures and markets a
broad range of innovative products to improve human and animal health,
directly and through its joint ventures. Merck headquarters are in
Whitehouse Station, N.J., USA. For more information, please visit
Aventis Pasteur has had one of the largest AIDS vaccine research programs
in the world for nearly 15 years, developing vaccines for both prophylactic
and therapeutic use. Focusing primarily on ALVAC-HIV, a canarypox vector
into which HIV genes are inserted, the company's HIV vaccines have been
studied in more than 40 clinical trials on five continents in more than 2,000
people since 1992. ALVAC-HIV was used in the first clinical trial undertaken
in Africa as well as in landmark trials in the Caribbean and South America.
ALVAC-HIV will be tested as part of a phase III clinical trial scheduled to
begin in Thailand in 2003.
Aventis Pasteur is the largest company in the world devoted entirely to
vaccines. In 2002, Aventis Pasteur produced 1.4 billion doses of vaccine,
making it possible to protect 500 million people across the globe, which is
about 1.4 million per day. The company offers the broadest range of
vaccines, providing protection against 20 bacterial and viral diseases.
Based in Lyon, France, Aventis Pasteur is owned by Aventis SA. For more
information, please visit www.aventispasteur.com.
Aventis is dedicated to treating and preventing disease by discovering
and developing innovative prescription drugs and human vaccines. In 2002,
Aventis generated sales of $17.6 billion, invested $3.1 billion in research
and development and employed approximately 71,000 people in its core
business. Aventis corporate headquarters are in Strasbourg, France. For
more information, please visit www.aventis.com.
Merck Forward-Looking Statement
This press release contains "forward-looking statements" as that term is
defined in the Private Securities Litigation Reform Act of 1995. These
statements involve risks and uncertainties which may cause results to differ
materially from those set forth in the statements. The forward-looking
statements include statements regarding product development and product
potential. No forward-looking statement can be guaranteed, and actual
results may differ materially from those projected. Additional detailed
information concerning a number of factors that could cause actual results to
differ materially is available in Item 1 of Merck's Annual Report on Form
10-K for the year ended Dec. 31, 2002, in its periodic reports on Form 10-Q
and in its reports on Form 8-K (if any). Copies of these forms are available
on request to Merck's Office of Stockholder Services.
Aventis Forward Looking Statement
Statements in this news release other than historical information are
forward-looking statements subject to risks and uncertainties. Actual
results could differ materially depending on such factors as the availability
of resources, the timing and effects of regulatory actions, the strength of
competition, the outcome of litigation and the effectiveness of patent
protection. Additional information regarding risks and uncertainties is set
forth in the current Annual Report on Form 20-F of Aventis on file with the
Securities and Exchange Commission.
(To reach Janet during the Keystone Conference
For Aventis Pasteur:
U.S. Press Contact:
Dr. Robert Sebbag
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