September 27, 2005

Halozyme Therapeutics 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 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 postinfarction improved to 69 percent in the group receiving rHuPH20. When rHuPH20 was conjugated with polyethylene glycol, survival in the same rat MCAO model increased to 78 percent. 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. Such increased edema and pressure rises also occur with other conditions, including cardiovascular disease, tumors and organ transplantation.