Pivotal Phase III Study for Subcutaneous Administration of Immunoglobulins Fully Enrolled

DEERFIELD, IL & SAN DIEGO, CA, USA | July 15, 2009 | Baxter International Inc. (NYSE:BAX) and Halozyme Therapeutics, Inc. (Nasdaq:HALO) today announced completion of patient enrollment in the Phase III pivotal study of GAMMAGARD LIQUID [Immune Globulin Intravenous (Human) 10%] (also known as KIOVIG outside of the United States) with rHuPH20 (recombinant human hyaluronidase enzyme) for the treatment of primary immunodeficiency disorder (PID). Patients will receive monthly subcutaneous (SC) injections of Halozyme’s rHuPH20 with Baxter’s GAMMAGARD LIQUID.

“The achievement of complete Phase III enrollment is an important milestone of Baxter’s work with Halozyme to offer patients more advanced treatment options,” said Hartmut J. Ehrlich, M.D., vice president of Global Research and Development for Baxter’s BioScience business.

“I am pleased with the efficiency and dedication Baxter has demonstrated toward our collaboration and their exemplary ability to manage and carry out the clinical objectives,” stated Jonathan Lim, M.D., Halozyme’s president and CEO. “Completion of patient enrollment in this Phase III registration study marks a significant and timely accomplishment for the GAMMAGARD LIQUID-rHuPH20 development program.”

This Phase III clinical trial is a prospective, open-label, non-controlled design underway in 15 centers in the U.S. and Canada. The study will evaluate the safety and efficacy of GAMMAGARD LIQUID administered SC with rHuPH20 in the prevention of acute serious bacterial infections over 12 months and will also assess pharmacokinetic parameters of SC GAMMAGARD LIQUID with rHuPH20 compared to intravenous (IV) administration of GAMMAGARD LIQUID alone. Patient Quality of Life (QOL) parameters will also be measured. Subcutaneous administration of GAMMAGARD LIQUID with rHuPH20 in this investigational study will determine if it will allow PID patients to receive a full monthly dose in a single injection site in the home setting. GAMMAGARD LIQUID is currently only approved for IV administration. Additional information about this Phase III study can be found at clinicaltrials.gov.

About GAMMAGARD LIQUID

GAMMAGARD LIQUID is indicated for the treatment of primary immunodeficiency disorders associated with defects in humoral immunity. These include but are not limited to congenital X-linked agammaglobulinemia, common variable immunodeficiency, Wiskott-Aldrich syndrome, and severe combined immunodeficiencies.

Important Safety Information

GAMMAGARD LIQUID is contraindicated in patients with known anaphylactic or severe hypersensitivity responses to Immune Globulin (Human). Patients with severe selective IgA deficiency (IgA < 0.05 g/L) may develop anti-IgA antibodies that can result in a severe anaphylactic reaction.

Immune Globulin Intravenous (Human) products have been reported to be associated with renal dysfunction, acute renal failure, osmotic nephrosis, and death. IGIV products should be administered at the minimum concentration available and the minimum rate of infusion practicable in at risk patients.

GAMMAGARD LIQUID is made from human plasma. It may carry a risk of transmitting infectious agents, e.g. viruses, and theoretically, the Creutzfeldt-Jakob disease (CJD) agent. Some viruses, such as B19V or hepatitis A, are particularly difficult to remove or inactivate.

GAMMAGARD LIQUID should only be administered intravenously.

Immediate anaphylactic and hypersensitivity reactions are a remote possibility.

IGIV products can contain blood group antibodies which may act as hemolysins and induce in vivo coating of red blood cells with immunoglobulin causing a positive direct antiglobulin reaction and, rarely, hemolysis. Hemolytic anemia can develop subsequent to IGIV therapy due to enhanced red blood cell sequestration.

There have been reports of noncardiogenic pulmonary edema (Transfusion Related Acute Lung Injury [TRALI]) in patients administered IGIV.

Thrombotic events have been reported in association with IGIV. The potential risks and benefits of IGIV should be weighed against those of alternative therapies.

Aseptic meningitis syndrome (AMS) has been reported to occur infrequently in association with GAMMAGARD LIQUID treatment. Discontinuation of IGIV treatment has resulted in remission of AMS within several days without sequelae.

For full prescribing information, please visit:
http://www.baxter.com/products/biopharmaceuticals/downloads/gamliquid_PI.pdf

About Baxter

Baxter International Inc., through its subsidiaries, develops, manufactures and markets products that save and sustain the lives of people with hemophilia, immune disorders, infectious diseases, kidney disease, trauma, and other chronic and acute medical conditions. As a global, diversified healthcare company, Baxter applies a unique combination of expertise in medical devices, pharmaceuticals and biotechnology to create products that advance patient care worldwide.

About Halozyme Therapeutics, Inc.

Halozyme is a biopharmaceutical company developing and commercializing products targeting the extracellular matrix for the endocrinology, oncology, dermatology and drug delivery markets. The company’s portfolio of products and product candidates is based on intellectual property covering the family of human enzymes known as hyaluronidases and additional enzymes that target the extracellular matrix. Halozyme’s Enhanze™ Technology is a novel drug delivery platform designed to increase the absorption and dispersion of biologics. The company has key partnerships with Roche to apply Enhanze Technology to Roche’s biological therapeutics for up to 13 targets and with Baxter BioScience to apply Enhanze Technology to Baxter’s biological therapeutic compound, GAMMAGARD LIQUID™. The product candidates in Halozyme’s research pipeline target multiple areas of significant unmet medical need. For more information visit www.halozyme.com.

SOURCE: Halozyme Therapeutics, Inc.