Peregrine Starts Phase 2 Trial of Monoclonal Antibody Hepatitis C Treatment

	SUMMARY: Peregrine Pharmaceuticals this week announced the start of a Phase 2 clinical trial to test a novel approach to hepatitis C virus (HCV) treatment using the monoclonal antibody bavituximab. The antibody -- which is also under study as a cancer chemotherapy -- works by binding to host cells infected with HCV, HIV, and certain other viruses, triggering an immune system attack. It will be studied in combination with ribavirin in previously untreated genotype 1 chronic hepatitis C patients.

Peregrine Initiates Randomized Phase II Trial of Bavituximab in Chronic Hepatitis C

Open-Label Trial Evaluating 12 Weeks of Therapy With Novel Targeted Antibody Bavituximab in Combination With Ribavirin Versus Standard of Care

Tustin, CA -- January 10, 2011 -- Peregrine Pharmaceuticals, Inc., a clinical-stage biopharmaceutical company developing first-in-class monoclonal antibodies for the treatment of cancer and viral infections, today announced that it has initiated a randomized Phase II clinical trial in patients with previously untreated genotype 1 hepatitis C virus (HCV) infection.

This open-label trial will determine the early virologic response (EVR) rate of patients after 12 weeks of therapy with Peregrine's bavituximab, a phosphatidylserine (PS)-targeting monoclonal antibody with immune-modulating potential, in combination with the antiviral drug ribavirin versus standard of care, pegylated interferon alpha 2a and ribavirin. Peregrine expects to complete enrollment shortly in an ongoing Phase Ib HCV trial and report data by mid-year.

"Our fourth randomized Phase II trial evaluating bavituximab for oncology and viral infections is designed to build on our three prior Phase I HCV trials, which have demonstrated our antibody's acceptable safety and promising signs of antiviral activity," said Steven W. King, president and chief executive officer of Peregrine. "Although there are several targeted antiviral drug candidates in development against HCV, immune stimulation with interferon remains a cornerstone of the standard HCV regimen, but unfortunately causes serious side effects and unacceptable toxicity for many patients. With bavituximab's immune reactivation mechanisms and safety profile to date, we are eager to assess this new combination as a potential alternative to interferon-based regimens for patients infected with HCV."

Bavituximab may address a fundamental "immune evasion" mechanism exploited by many infectious pathogens. A growing body of published data from researchers worldwide shows that bavituximab's PS target, exposed on the surface of cells infected by viruses and protozoan parasites, suppresses the immune system's ability to fight disease. PS-targeting antibodies such as bavituximab bind to PS and block the immunosuppressive signals created by the target, thereby allowing the immune system to mount a robust immune response against the pathogen. In prior HCV clinical trials, bavituximab administered as monotherapy in single and multiple doses demonstrated a positive safety profile with no dose-limiting toxicities or serious adverse events. Bavituximab as a monotherapy also showed promising on therapy antiviral activity of up to 1.5 log viral load reduction.

About the Phase II HCV Trial

In this multicenter Phase II randomized, open-label trial, up to 66 patients with previously untreated genotype 1 chronic HCV infection will be randomly assigned to one of three treatment arms. Patients will receive daily oral ribavirin (1000 mg) with either weekly bavituximab (0.3 mg/kg or 3 mg/kg) or [pegylated interferon] alpha-2a (180 mcg) for up to 12 weeks and will be tested for safety parameters and antiviral activity.

The primary endpoint of the study is the proportion of patients achieving early virologic response (EVR), an early predictor of which patients are likely to clear virus with continued treatment. EVR is defined as a greater than or equal to 2 log reduction in HCV RNA after 12 weeks of treatment. Secondary endpoints include safety, tolerability and HCV viral kinetics. For further information about this trial, please visit www.peregrinetrials.com or www.clinicaltrials.gov/ct2/results?term=bavituximab.

About Bavituximab's Antiviral Approach

Bavituximab is the first in a new class of patented antibody therapeutics that target and bind to phosphatidylserine (PS), a specific phospholipid component of cell membranes. Bavituximab helps reactivate and direct the body's immune system to destroy infected cells and virus particles that exhibit this specific phospholipid on their surface. Since their target is host-derived rather than pathogen-derived, PS-targeting antibodies have the potential for broad-spectrum antiviral activity and are also expected to be much less susceptible to the viral mutations that often lead to drug resistance.

Researchers have found that PS is exposed on the outer membrane of cells infected with HCV, HIV, influenza, herpes viruses, hemorrhagic fever viruses, respiratory syncytial virus, measles as well as other viruses. A growing body of scientific publications, including Nature Medicine and Journal of Experimental Medicine, has highlighted data on the role of PS and Peregrine's PS-targeting therapies in infectious diseases.

About Peregrine Pharmaceuticals

Peregrine Pharmaceuticals, Inc. is a biopharmaceutical company with a portfolio of innovative monoclonal antibodies in clinical trials for the treatment of cancer and serious viral infections. The company is pursuing multiple clinical programs in cancer and hepatitis C virus infection with its lead product candidate bavituximab and novel brain cancer agent Cotara. Peregrine also has in-house cGMP manufacturing capabilities through its wholly-owned subsidiary Avid Bioservices, Inc. (www.avidbio.com), which provides development and biomanufacturing services for both Peregrine and outside customers. Additional information about Peregrine can be found at www.peregrineinc.com.