March 2014...Preclinical Data Presentations at Keystone Symposia Highlight Broad Immunotherapy Potential of Peregrine Pharmaceuticals' PS-Targeting Antibodies
Oral Plenary Presentation Details Ability of PS-Targeting Antibodies to Reactivate Tumor Immunity at Multiple Levels and Enhance the Anti-Tumor Effects of Anti-PD-1 Antibodies; Data Presented Supports PS-Binding Antibody's Ability to Inhibit HIV Infection In Vitro; Recent Data Supports the PS Mediated Immunosuppression in Aiding Infectious Disease Progression Opening the Potential of PS Targeting Immune Checkpoint Therapeutic Combinations
TUSTIN, CA -- (Marketwired) -- 03/13/14 -- Peregrine Pharmaceuticals, Inc. (NASDAQ: PPHM) (NASDAQ: PPHMP) today announced that preclinical data presented at two Keystone Symposia support the immune-stimulatory mechanism of action and therapeutic potential of the company's phosphatidylserine (PS)-targeting antibodies in both oncology and antiviral therapeutic areas. These data were detailed in presentations at the Keystone Immune Evolution in Cancer symposium in Whistler, British Columbia, Canada and the Keystone HIV Pathogenesis - Virus vs. Host symposium in Banff, Alberta, Canada. Peregrine's lead PS-targeting antibody, bavituximab, is currently being evaluated in second-line non-small cell lung cancer (NSCLC) as part of the SUNRISE pivotal Phase III clinical trial.
In a poster titled, "Phosphatidylserine-Targeting Antibody Triggers ß-Chemokine Release from Monocytes by Cell-Cell Crosslinking and is a Potent Inhibitor of HIV-1 In Vitro", Cyril Empig, Ph.D., associate director of preclinical research in infectious disease at Peregrine, presented data from studies conducted by Duke University and Peregrine researchers that further characterizes the mechanism by which the PS-binding antibody PGN632 inhibits the HIV infection of cells. Results revealed that PGN632 stimulates immune cells to link together and secrete molecules that block viral receptors used by HIV to infect cells. Furthermore, the immune-stimulatory mechanism of PS-targeting antibodies was further validated as study results showed that the antiviral mechanism of action was dependent on using the full length antibody rather than an antibody fragment that simply blocks PS.
"The immunosuppressive effects of phosphatidylserine, or PS, during routine cell death and the way in which tumors and infectious diseases exploit high levels of PS to evade immune surveillance are now very well-established through an abundance of peer-reviewed scientific publications from researchers worldwide," said Cyril Empig, Ph.D., associate director of preclinical research in infectious disease at Peregrine. "PGN632 appears to have an antiviral mechanism of action that is quite potent at inhibiting HIV in vitro and we look forward to further collaborative studies using PGN632 and in combination with other immune enhancing agents to evaluate their potential therapeutic effects in vivo."
In an oral presentation titled, "Phosphatidylserine-Targeting Antibodies Induce M1 Macrophage Polarization, Promote Myeloid Derived Suppressor Cell Differentiation and Boost Tumor-Specific Immunity" Xianming Huang, Ph.D., of The University of Texas Southwestern Medical Center in Dallas, presented data from studies demonstrating that PS-targeting antibodies override PS-mediated immune suppression in tumors and induce multiple downstream immune-stimulatory effects. Results showed a reduction of highly immunosuppressive myeloid derived suppressor cells (MDSC), increases in inflammatory cytokines, tumor-fighting M1 macrophages, mature dendritic cells and tumor-specific cytotoxic T-cells. Additionally, combination therapy studies utilizing a PS-targeting antibody with an anti-PD-1 antibody yielded enhanced therapeutic results in a preclinical model of melanoma, including delays and reductions in tumor growth compared to either antibody administered alone.
"Data presented at Keystone this week also point to increasing recognition of PS as playing an immunosuppressive role during the chronic phase of infectious disease. The supportive data presented this week will allow us to further insert PS into the immunotherapy discussion and we look forward to the possibility for future potential collaborative studies in both oncology and infectious diseases," said Jeff T. Hutchins, Ph.D., vice president of preclinical research at Peregrine. "We are pleased that PS and the PS receptor pathway have attracted an increasing amount of attention among cancer immunotherapy researchers and that PS is now seen as both an upstream immune checkpoint and novel drug target in this promising new area of cancer treatment."
Copies of these posters are located in the Upcoming Events section of the Investors tab of Peregrine's website www.peregrineinc.com.
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