Peregrine Pharmaceuticals Hosts Annual Meeting; Highlights Bavituximab's Potential in Solid Tumor Therapy

Peregrine Pharmaceuticals, Inc. (NASDAQ: PPHM), a biopharmaceutical company developing first-in-class monoclonal antibodies focused on the treatment and diagnosis of cancer,today highlighted data presented at the Annual Meeting of the AmericanAssociation for Cancer Research (AACR). Data was presented this week frompreclinical studies investigating the immune-stimulating mechanism of actionof Peregrine's lead phosphatidylserine (PS)-targeting oncology clinicalcandidate bavituximab and the anti-tumor and imaging potential of otherPS-targeting molecules. Bavituximab is currently being evaluated in severaloncology clinical trials including the lead indication of second-linenon-small cell lung cancer (NSCLC), which is anticipated to advance into apivotal Phase III trial later this year. "These studies yield important insights into the fundamental role thatexposed PS plays in tumor immune evasion, and further support our leadclinical candidate bavituximab's ability to reactivate tumor immunity. Thisis now clearly evidenced by several specific measurements of both theimmune-stimulating and anti-tumor mechanisms mediated by PS-targetingantibodies as well as imaging studies demonstrating that tumor growthinhibition is correlated with PS expression levels in tumors," said Jeff T.Hutchins, Ph.D., vice president of preclinical research at PeregrinePharmaceuticals. "Included in these presentations was a compelling findingof a pronounced antibody-mediated increase in tumor-fighting immune cellsthat is independently correlated with an impressive survival benefit inpatients with NSCLC based on a published retrospective study of clinicaldata(1) . When taken together, these results support PS as a promisingoncology drug target and provide additional rationale for the impressivePhase II survival data we have seen in bavituximab's lead indication ofsecond-line NSCLC." Data presented from imaging studies(2) demonstrate that the chemotherapeuticdrug docetaxel, a commonly prescribed second-line treatment for patientswith advanced NSCLC, increases the exposure of bavituximab's targetmolecule, phosphatidylserine (PS), on tumor blood vessel cells and tumorcells. Results also showed that PS exposure in tumors is correlated withtumor burden and response to docetaxel treatment, supporting exposed PS as apromising biomarker of cancer and response to therapy. Peregrine'sPS-targeting imaging agent I-124-PGN650 is currently being evaluated in aclinical trial to assess its safety and potential to image multiple tumortypes in patients with cancer. Additional data presented from a series of preclinical studies(3)demonstrate that PS-targeting antibodies mediate immuno-stimulatory changesin tumors resulting in an increase of tumor-fighting (M1) macrophages,immune cells strongly associated with survival benefits in patients withNSCLC(1) . Peregrine recently reported promising data from a randomized,double-blind, placebo-controlled Phase II second-line NSCLC clinical trialdemonstrating a 60% improvement in median overall survival (OS) in patientsreceiving 3 mg/kg bavituximab plus docetaxel compared to the control arm.The company plans to meet with the U.S. Food and Drug Administration (FDA)in the second quarter of calendar year 2013 with the goal of initiating aPhase III trial by calendar year-end. Researchers also presented details of new PS-binding constructs(4) . Termed"betabodies," the molecules consist of the PS-binding domain of the serumprotein 2GPI), fused to the constant region ofan antibody. Betabodies bind to PS directly, are smaller in size and have alonger serum half-life than natural antibodies. Early studies indicate thatbetabodies hold potential as next-generation PS-binding agents that have thepotential to be used for a broad number of applications includingantibody-drug conjugates and next generation therapeutics for oncology andinfectious diseases.