SAN DIEGO, Sept. 27 /PRNewswire-FirstCall/ -- Halozyme Therapeutics, Inc. , a biopharmaceutical company focused on the development and commercialization of recombinant human enzymes, presented new pharmacokinetic and efficacy data with a novel, chemically modified form of a recombinant human hyaluronidase enzyme in animal ischemic stroke models. The data were presented at the 2005 American Neurological Association annual meeting in San Diego.
The enzyme, called rHuPH20, when conjugated to polyethylene glycol (PEG), demonstrated a dramatically longer serum half life (approximately 100 fold) compared with the unmodified form, thereby preventing it from being rapidly cleared from circulation. Both rHuPH20 and PEG-rHuPH20 demonstrated increased survival in stroke models.
When injected intravenously in rodent models of severe ischemic stroke, enzyme treated animals showed significantly increased survival compared to saline controls over 28 days after stroke. Survival at 28 days post- infarction improved to 69% in the group receiving 50Âµg/kg rHuPH20, from 48% in saline controls, two hours post-infarction and every 48 hours thereafter for 14 days (p=0.049, n=40 animals per group). When rHuPH20 was conjugated with polyethylene glycol, survival in the same rat MCAO model increased to 78% (p=0.006, n=40 animals per group). The enzyme appeared to prevent death in treated animals by reducing edema (or swelling) within the brain. Brain edema can occur after severe strokes when large regions of the brain are deprived of blood flow. These findings are of particular interest in that reducing edema in ischemic stroke patients may limit the deadly progression of the disease that can occur due to uncontrollable pressure rises. Such increased edema and pressure rises also occur with other conditions, including cardiovascular disease, tumors, and organ transplantation.
"This is extremely encouraging work, and suggests potential utility in reducing brain injury from edema in ischemic stroke," commented Gregory Del Zoppo, MD, Associate Professor of The Scripps Research Institute and world- renowned expert in novel stroke therapeutics. "Future studies are warranted that could potentially lead to exciting data and translate into real clinical benefit."
"While hyaluronidase enzymes have been tested in the clinic previously by intravenous administration, few studies have examined the pharmacokinetics of these molecules," said Gregory Frost, PhD, Halozyme's Vice President and Chief Scientific Officer. "A significant limitation for intravenous use has been their remarkably short half life. Modifying the human enzyme with PEG to produce a greatly improved half life while keeping the enzyme catalytically active represents a significant achievement for the scientific team at Halozyme and potentially opens new avenues for future development."
Halozyme's family of recombinant human glycosaminoglycan degrading enzymes are being studied for their ability to degrade hyaluronic acid (HA) and other glycosaminoglycans in the body for drug delivery and for treatment of medical conditions resulting from pathologic accumulation of these materials.
About Halozyme Therapeutics, Inc.
Halozyme is a biopharmaceutical company dedicated to developing and commercializing recombinant human enzymes for the infertility, ophthalmology, and oncology communities. The company's portfolio of products under development is based on intellectual property covering the family of human enzymes known as hyaluronidases. Halozyme's recombinant human enzymes may replace current animal slaughterhouse-derived enzymes that carry potential risks of animal pathogen transmission and immunogenicity. The versatility of the first enzyme, rHuPH20, enables Halozyme to develop the product as a medical device, drug enhancement agent, and therapeutic biologic.
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Halozyme Therapeutics, Inc.