- Two New Studies Provide Further Evidence that PS Plays a Critical Role in
Some Viral Infections -
- Peregrine's Anti-PS Antibody Bavituximab is Currently Being Assessed in a
Clinical Trial in HCV Patients Co-Infected with HIV -
TUSTIN, Calif., May 13 /PRNewswire-FirstCall/ -- Peregrine
Pharmaceuticals, Inc. (Nasdaq: PPHM), a clinical stage biopharmaceutical
company developing monoclonal antibodies for the treatment of cancer and
hepatitis C virus (HCV) infection, today reported that two independent
studies recently published in the journal Science (1,2) highlight the
critical importance of the cellular membrane lipid phosphatidylserine (PS)
in the ability of some enveloped viruses to infect cells. Peregrine is a
leader in the development of anti-PS therapies. Its lead anti-PS antibody
bavituximab has successfully completed two Phase I trials in HCV patients
and is currently in a clinical trial in patients co-infected with HCV and
HIV. Bavituximab is also being assessed in a Phase I single agent cancer
study and in Phase II cancer trials in combination with chemotherapy.
"These two excellent studies from independent groups of researchers
exemplify the growing interest in the scientific community in the role of
PS in viral infectivity and important aspects of immunity," said Steven W.
King, president and CEO of Peregrine. "In particular, we believe that the
paper discussing the vaccinia virus(1) independently confirms some of the
key mechanisms underlying the anti-viral potential of our anti-PS
antibodies. It shows that PS is essential to the ability of the virus to
infect cells, and that when PS is blocked, infection cannot occur. The
study also discusses how PS helps the virus to evade immune system
recognition and destruction, a key secondary mechanism we believe is
operative in both the anti-viral and anti-cancer applications of our
anti-PS technology."
In a separate Science Perspective article discussing the studies(3),
the commentators note that the essential role of PS may not be limited to
vaccinia infections, but may also play a role in HIV infection. Vaccinia
and HIV are both enveloped viruses, and as the articles discuss, PS becomes
exposed on the surface of enveloped viruses and the cells they infect. This
is consistent with findings by Peregrine researchers showing that its
anti-PS antibodies bind to every enveloped virus tested. The company's
anti-PS antibodies have also demonstrated promising anti-viral activity
against a number of enveloped viruses in preclinical tests, as well as in
clinical trials in patients infected with HCV, which is an enveloped virus.
In addition to the ongoing clinical trial in HCV patients co-infected with
HIV, Peregrine's anti-PS antibodies are currently being studied in animal
models of HIV.
Peregrine's anti-PS technology is exclusively licensed from the
University of Texas Southwestern Medical Center at Dallas, where Dr. Philip
Thorpe has been a pioneer in investigating the role of
anti-phosphatidylserine therapies in viral infections and cancer for more
than a decade.
"It is gratifying to see the growing momentum of scientific interest
and inquiry in the unique role of PS in immune system function and
dysfunction," said Dr. Thorpe. "Our extensive work in the potential of
anti-PS therapies for treating virus infections and cancer has been
predicated on the same types of mechanisms that are elucidated and
discussed in these first-rate studies, and we welcome the independent
corroboration and additional insights that this new research is providing
to the field."
About Peregrine's Anti-PS Antibody Bavituximab
Peregrine's clinical stage monoclonal antibody bavituximab is in
development for the treatment of certain viral diseases and cancer. It is
the first in a new class of targeted anti-PS immunotherapeutics that binds
to phosphatidylserine, a specific component of certain cellular membranes.
PS is normally present only on the inside of cell membranes, but becomes
exposed on the external surface of enveloped viruses and the cells they
infect. Enveloped viruses are responsible for about half of all human viral
diseases, including HCV, influenza, HIV, cytomegalovirus and other virus
strains. Scientists believe that bavituximab helps block the ability of
viruses to infect cells and also helps stimulate the body's natural immune
defenses to destroy both the virus particles and infected cells. Since the
PS targeted by bavituximab is primarily exposed on diseased cells, healthy
cells should not be affected.
In preclinical studies, bavituximab has demonstrated the ability to
bind to a wide range of enveloped viruses and virally infected cells and
has shown promising activity in animal models of serious viral diseases.
Bavituximab appeared well tolerated with no dose limiting adverse events
and showed encouraging signs of antiviral activity as monotherapy in two
Phase I trials in patients with chronic hepatitis C viral infection. A
clinical trial in patients co-infected with HCV and HIV is now underway,
and additional studies in HCV patients are planned. Similar to their
proposed anti-viral mechanism, anti-PS antibodies also bind to
phosphatidylserine exposed on tumor blood vessels in all solid cancers
tested to date. Bavituximab demonstrated promising signs of anti-tumor
activity in a Phase l trial in combination with chemotherapy in patients
with advanced solid tumors, and Phase II cancer trials are underway.
1. Vaccinia Virus Uses Macropinocytosis and Apoptotic Mimicry to Enter
Host Cells, Jason Mercer and Ari Helenius* Science 25 April 2008: Vol. 320.
no. 5875, pp. 531 - 535
2. Role of C. elegans TAT-1 Protein in Maintaining Plasma Membrane
Phosphatidylserine Asymmetry, Monica Darland-Ransom, Xiaochen Wang,*
Chun-Ling Sun,* James Mapes, Keiko Gengyo-Ando, Shohei Mitani, Ding Xue,
Science 25 April 2008: Vol. 320. no. 5875, pp. 528 - 531
3. CELL BIOLOGY: A One-Sided Signal, Gregory D. Fairn and Sergio
Grinstein (25 April 2008)Science 320 (5875), 458.
About Peregrine Pharmaceuticals
Peregrine Pharmaceuticals, Inc. is a biopharmaceutical company with a
portfolio of innovative product candidates in clinical trials for the
treatment of cancer and hepatitis C virus (HCV) infection. The company is
pursuing three separate clinical programs in cancer and HCV infection with
its lead product candidates bavituximab and Cotara(R). Peregrine also has
in- house manufacturing capabilities through its wholly owned subsidiary
Avid Bioservices, Inc. (http://www.avidbio.com), which provides development and
bio- manufacturing services for both Peregrine and outside customers.
Additional information about Peregrine can be found at
http://www.peregrineinc.com.
Safe Harbor Statement: Statements in this press release which are not
purely historical, including statements regarding Peregrine
Pharmaceuticals' intentions, hopes, beliefs, expectations, representations,
projections, plans or predictions of the future are forward-looking
statements within the meaning of the Private Securities Litigation Reform
Act of 1995. The forward-looking statements involve risks and uncertainties
including, but not limited to, the risk that the promising anti-viral
activity demonstrated against enveloped viruses in preclinical studies may
not be demonstrated in clinical trials. It is important to note that the
company's actual results could differ materially from those in any such
forward-looking statements. Factors that could cause actual results to
differ materially include, but are not limited to, uncertainties associated
with completing preclinical and clinical trials for our technologies; the
early stage of product development; the significant costs to develop our
products as all of our products are currently in development, preclinical
studies or clinical trials; obtaining additional financing to support our
operations and the development of our products; obtaining regulatory
approval for our technologies; anticipated timing of regulatory filings and
the potential success in gaining regulatory approval and complying with
governmental regulations applicable to our business. Our business could be
affected by a number of other factors, including the risk factors listed
from time to time in the company's SEC reports including, but not limited
to, the annual report on Form 10-K for the year ended April 30, 2007 and
the quarterly report on Form 10-Q for the quarter ended January 31, 2008.
The company cautions investors not to place undue reliance on the
forward-looking statements contained in this press release. Peregrine
Pharmaceuticals, Inc. disclaims any obligation, and does not undertake to
update or revise any forward-looking statements in this press release.
Contacts:
GendeLLindheim BioCom Partners
Investors Media
info@peregrineinc.com Barbara Lindheim
(800) 987-8256 (212) 918-4650
SOURCE Peregrine Pharmaceuticals, Inc.
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Related links:
http://www.peregrineinc.com
CONTACT:
GendeLLindheim BioCom Partners, Investors,
1-800-987-8256, info@peregrineinc.com, or Media, Barbara
Lindheim, +1-212-918-4650, for Peregrine Pharmaceuticals, Inc.
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