Data Supporting Bavituximab's Immunotherapy Mechanism of Action Published in the Peer-Reviewed AACR Journal Cancer Immunology

Data Supporting Bavituximab's Immunotherapy Mechanism of Action Published in 
the Peer-Reviewed AACR Journal Cancer Immunology
Published Data Shows PS-Targeting Antibodies Such as Bavituximab
Activate Tumor-Specific Immune Responses by Blocking PS-Mediated
Immunosuppression; PS-Targeting Antibody Therapy Results in Adaptive
Immune Responses Including Development of Tumor Specific Cytotoxic
T-Cells; Peregrine to Initiate Bavituximab Phase III Clinical Trial
in Second-Line NSCLC by Year-End 
TUSTIN, CA -- (Marketwired) -- 09/09/13 --  Peregrine Pharmaceuticals
(NASDAQ: PPHM) today announced the publication of preclinical
research highlighting the immune-stimulatory mechanism of action of
phosphatidylserine (PS)-targeting antibodies, such as the company's
lead drug candidate bavituximab. The manuscript details the results
from a series of studies demonstrating that exposed PS plays a major
role in the inhibition of pro-inflammatory cellular and cytokine
responses in tumors and that PS-targeting antibodies override this
primary upstream immune checkpoint, activating multiple downstream
immunostimulatory effects, including the conversion of myeloid
derived suppressor cells into tumor immunity promoting M1 macrophages
and the generation of tumor killing cytotoxic T-cells. 
"The mechanism of action data in this publication has transformed our
understanding of bavituximab and supports many new areas of
development for bavituximab. Since the initial data demonstrating
bavituximab's immunotherapy mechanism were presented earlier this
year, we have undertaken preclinical studies to actively explore new
combinations and approaches for potential bavituximab therapies,"
said Jeff T. Hutchins, Ph.D. vice president, preclinical research of
Peregrine Pharmaceuticals. "As immunotherapy combinations have shown
great promise recently in treating cancer and as PS is known to be a
primary upstream inhibitory checkpoint for tumor immune recognition,
we believe there are many immunotherapy combination options for
bavituximab. As such, our ongoing preclinical studies are designed to
read out in the coming months to guide our clinical trial development
strategy for these combinations." 
These results appear in the American Association for Cancer Research
(AACR) peer-reviewed journal, Cancer Immunology Research, in a
manuscript titled: "Phosphatidylserine-targeting antibody induces M1
macrophage polarization and promotes myeloid derived suppressor cell
In the online released manuscript, researchers examined whether 2aG4,
the mouse equivalent antibody to bavituximab, could reverse the known
immunosuppressive effects of exposed PS in the tumor environment.
Results showed that 2aG4 reactivated antitumor immunity on multiple
levels including the switching of tumor associated macrophages to a
tumoricidal M1-like phenotype, the reduction of myeloid-derived
suppressor cells (MDSC) in tumors, an increase in immunostimulatory
signaling chemicals (cytokines) and the maturation of dendritic cells
into functional antigen-presenting cells (APC) leading to
tumor-specific cytotoxic T-cell responses. These multiple anti-tumor
effects were further shown to occur without the side-effects
associated with systemic immune activation. 
"Data like those just published are critical to guiding our clinical
strategy for bavituximab. First, they further support the synergistic
potential of bavituximab with docetaxel, which will be evaluated by
Peregrine in a global pivotal Phase III trial for non-small-cell lung
cancer to be initiated by year-end. Second, these new mechanistic
insights open up many opportunities for collecting data from ongoing
trials to further confirm in the clinic these findings from
preclinical studies. We plan to test samples from ongoing studies and
the results could be very important in guiding the clinical
development program," said Anshu Vashishtha, M.D., Ph.D., senior
medical director of Peregrine Pharmaceuticals. "Third, these new data
also serve as the foundation for our ongoing preclinical development
program focused on the possibility of new immunotherapy combinations
in upcoming clinical trials. We continue to work closely with the
preclinical researchers to evaluate the optimal immunotherapy
combinations, and believe that we can advance one or more of these
combinations into clinical trials in the near future."  
A copy of the article is available at: 
About Peregrine Pharmaceuticals, Inc. 
Peregrine Pharmaceuticals, Inc. is a biopharmaceutical company with a
portfolio of innovative monoclonal antibodies in clinical trials
focused on the treatment and diagnosis of cancer. The company is
pursuing multiple clinical programs in cancer with its lead
immunotherapy candidate bavituximab and novel brain cancer agent
Cotara(R). Peregrine also has in-house cGMP manufacturing
capabilities through its wholly-owned subsidiary Avid Bioservices,
Inc. (, which provides development and
biomanufacturing services for both Peregrine and third-party
customers. Additional information about Peregrine can be found at 
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 results from ongoing proof-of-concept studies
may not be consistent with the results published in the manuscript,
the risk that combining bavituximab with other antibodies that
enhance tumor immunity, such as an anti-PD1, anti-PD-L1, or
anti-CTLA-4, may not result in any additional benefit, and the risk
that company may not be able to initiate the Phase III trial within
its anticipated timeline. 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 our reports filed with the Securities and
Exchange Commission including, but not limited to, our annual report
on Form 10-K for the fiscal year ended April 30, 2013. 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. 
Christopher Keenan
Jay Carlson 
Peregrine Pharmaceuticals 
(800) 987-8256 
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