In an editorial
commentary(1) in the current issue of The Journal of Infectious Diseases
(JID), independent experts on cytomegalovirus (CMV) said the vaccine under
development by Vical Incorporated (Nasdaq: VICL), at the optimal dose and
regimen tested, "holds promise" based on its ability to elicit persistent
immune responses in a majority of CMV-seronegative subjects, and warrants
further evaluation for its potential to prevent infection and disease. The
commentary accompanies the issue's lead article(2), which expands on
previously reported immunogenicity data from a Phase 1 study of the
immunotherapeutic DNA vaccine.
The senior author on the JID article, Michael J. Boeckh, M.D., said,
"Despite antiviral drug therapies, CMV infection continues to be a problem
in the transplant setting. CMV immunity appears to play a critical role in
controlling viral load and disease in these patients. The ability to
stimulate CMV immunity with vaccination may have an important role in the
management of CMV infection and disease in transplant patients. Clinical
trials are ongoing to test this strategy."
Dr. Boeckh, Associate Member of the Fred Hutchinson Cancer Research
Center and Associate Professor at the University of Washington, also is an
investigator in Vical's current Phase 2 trial, a double-blind, placebo-
controlled study designed to compare safety of the vaccine against placebo
in approximately 80 patients scheduled for hematopoietic stem cell
transplants. Because most recipients are expected to face a natural viral
challenge as pre- existing CMV infection reactivates under
immunosuppression, this trial will examine the vaccine's impact on
important clinical parameters such as antiviral drug use and viral load in
patients receiving vaccine compared with patients receiving placebo. Other
important evaluations will include measurement of specific immune responses
against CMV targeted by the vaccine.
"We are advancing well toward completion of enrollment in our Phase 2
CMV vaccine trial," said Ronald B. Moss, M.D., Vice President of Clinical
Development at Vical, "and are on track for our planned interim evaluation
of safety and efficacy data in the second half of 2008. Our
immunotherapeutic vaccine may help address the serious healthcare problem
of CMV reactivation for transplant patients, and could eventually be useful
in preventing birth defects caused by CMV infection of pregnant women."
About CMV
CMV is a herpes virus that infects more than half of all adults in the
United States by age 40, and is even more widespread in developing
countries. While a healthy immune system typically protects an infected
person against CMV disease, it rarely succeeds in completely eliminating
the infection, and those whose immune systems are not fully functional are
at high risk of CMV proliferation, potentially leading to severe illness or
death. These include transplant patients who take immunosuppressive drugs,
and fetuses and newborns of mothers who first become infected during
pregnancy.
CMV infection affects 30 to 60 percent of the patients undergoing
various transplant procedures, causing transplant rejection, serious
illness and even death if untreated. Expensive antiviral drug therapy is
used to control the disease, but does not eliminate the infection.
Congenital CMV infection affects one out of every hundred infants, and
causes severe consequences in about 3,600 infants and death in about 400
each year in the United States.
There is no approved vaccine against CMV. Vaccine approaches that
result in predominantly antibody responses to CMV have not proven highly
effective in transplant patients. Vaccine approaches using live, attenuated
viruses can induce both antibody and cellular immune responses, but pose a
potential safety concern, particularly for immunocompromised patients, of
causing the disease they are intended to prevent. Vical's novel DNA vaccine
approach is designed to induce both antibody and cellular immune responses
against specific features of the CMV virus without the risk of causing CMV
disease. Vical's vaccine has received orphan drug designation for
hematopoietic stem cell transplant and solid organ transplant patients.
About Vical
Vical researches and develops biopharmaceutical products based on its
patented DNA delivery technologies for the prevention and treatment of
serious or life-threatening diseases. Potential applications of the
company's DNA delivery technology include DNA vaccines for infectious
diseases or cancer, in which the expressed protein is an immunogen; cancer
immunotherapeutics, in which the expressed protein is an immune system
stimulant; and cardiovascular therapies, in which the expressed protein is
an angiogenic growth factor. The company is developing certain infectious
disease vaccines and cancer therapeutics internally. In addition, the
company collaborates with major pharmaceutical companies and biotechnology
companies that give it access to complementary technologies or greater
resources. These strategic partnerships provide the company with mutually
beneficial opportunities to expand its product pipeline and address
significant unmet medical needs. Additional information on Vical is
available at http://www.vical.com.
This press release contains forward-looking statements subject to risks
and uncertainties that could cause actual results to differ materially from
those projected, including: whether Vical or others will continue
development of the CMV vaccine; whether the company will complete an
interim evaluation of safety and efficacy in the Phase 2 trial in the
second half of 2008, if at all; whether memory T-cells will result in
control of CMV disease; whether the company's DNA vaccine candidate will be
effective in protecting humans against CMV disease; whether the company
will successfully enroll 80 stem cell transplant recipients in a timely
manner, if at all; whether the CMV vaccine will achieve the safety and
efficacy endpoints in the Phase 2 trial; whether the company will expand
development of a CMV vaccine to address prevention of congenital disease;
whether Vical or its collaborative partners will seek or gain approval to
market any product candidates; whether Vical or its collaborative partners
will succeed in marketing any product candidates; and additional risks set
forth in the company's filings with the Securities and Exchange Commission.
These forward-looking statements represent the company's judgment as of the
date of this release. The company disclaims, however, any intent or
obligation to update these forward-looking statements.
References
(1) Go V, Pollard RB. A Cytomegalovirus Vaccine for Transplantation:
Are We Closer? J Infect Dis 2008;
(http://www.journals.uchicago.edu/toc/jid/current) 197:1631-3.
(2) Wloch MK et al. Safety and Immunogenicity of a Bivalent
Cytomegalovirus DNA Vaccine in Healthy Adult Subjects. J Infect Dis 2008;
(http://www.journals.uchicago.edu/toc/jid/current) 197:1634-42.
Vical Incorporated
http://www.vical.com