Halozyme Begins Phase 1 Clinical Study with PEGPH20 in Cancer Patients with Refractory Solid Tumors

SAN DIEGO--(BUSINESS WIRE)--Mar. 31, 2009-- Halozyme Therapeutics, Inc. (Nasdaq:HALO), a biopharmaceutical company developing and commercializing products targeting the extracellular matrix for the endocrinology, oncology, dermatology, and drug delivery markets, today announced the commencement of patient dosing in a Phase 1 clinical trial with PEGPH20 in cancer patients with refractory solid tumors. This multi-center, open-label, dose-escalation study will explore the safety, tolerability, pharmacokinetics and radiologic assessment of intravenous administration of PEGPH20 as a single agent with repeat dosing.

"As a result of our successful IND submission earlier this year, the first clinical trial with PEGPH20 is now underway," said Jonathan Lim, M.D., Halozyme's President and CEO. "Our previously reported preclinical studies demonstrated that PEGPH20 can deplete hyaluronan coats from tumor cells following systemic administration, lower interstitial fluid pressure and slow tumor growth. PEGPH20 may represent a unique approach and offer a novel mechanism of action for the treatment of solid tumors by targeting the hyaluronan component of the tumor microenvironment."

The trial will evaluate PEGPH20 over a range of doses and enroll up to 46 advanced cancer patients who will receive treatment cycles of intravenous PEGPH20 twice weekly for three weeks followed by one week without dosing. Patients may continue subsequent cycles at their assigned dose as long as there is no tumor progression and no unacceptable toxicity. Groups of four to eight patients will be assigned to each dosage cohort. The primary outcome measures of the study are to evaluate safety and tolerability of PEGPH20 and to determine the recommended Phase 2 dose. Secondary objectives will be to determine pharmacokinetics, obtain dose limiting toxicities, and observe patients for any evidence of anti-tumor activity. Translational radiologic, biopsy and pharmacodynamic measurements will also be examined.

Background and Preclinical Results for PEGPH20

Halozyme has assessed the anti-tumor activity of PEGPH20 in several animal tumor models. The studies, conducted in mouse tumor models that produce hyaluronan (HA), demonstrated that PEGPH20 removed HA from the tumor microenvironment and reduced tumor interstitial fluid pressure in a dose dependent fashion, with resultant tumor growth inhibition and prolonged time to progression compared to controls. In contrast, treatment of HA negative tumors showed no reduction of tumor pressure, no suppression of tumor volume growth, or no improvement in time to progression.

Hyaluronan is a constituent of the extracellular matrix in subsets of many solid tumor types, including prostate, breast, colon, pancreatic, ovarian and gastric where it may increase resistance to anti-cancer therapeutic agents and contribute to an elevation in tumor interstitial fluid pressure. Pegylation refers to the covalent attachment of polyethylene glycol to a molecule, usually a drug or therapeutic protein. Pegylation of the rHuPH20 enzyme increases its plasma half-life to greater than 24 hours compared to less than 30 seconds for the unpegylated enzyme, resulting in a longer duration of action.

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 affect 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. Halozyme's research pipeline candidates target significant areas of unmet medical need. For more information visit https://www.halozyme.com.

Safe Harbor Statement

In addition to historical information, the statements set forth above include forward-looking statements (including, without limitation, statements concerning the safety and efficacy of PEGPH20) that involve risk and uncertainties that could cause actual results to differ materially from those in the forward-looking statements. The forward-looking statements are also identified through use of the words "believe," "enable," "may," "will," "could," "intends," "estimate," "anticipate," "plan," "predict," "probable," "potential," "possible," "should," "continue," and other words of similar meaning. Actual results could differ materially from the expectations contained in forward-looking statements as a result of several factors, including regulatory approval requirements and competitive conditions. These and other factors that may result in differences are discussed in greater detail in the company's reports on Forms 10-K, 10-Q, and other filings with the Securities and Exchange Commission.

Source: Halozyme Therapeutics, Inc.

Halozyme Therapeutics, Inc.Robert H. Uhl, Senior Director, Investor Relations, [email protected]