Halozyme Therapeutics, Inc.'s Phase 1b Clinical Trial of PEGPH20 With Gemcitabine Indicates Positive Activity Against Pancreatic Cancer

SAN DIEGO, June 3, 2013 /PRNewswire/ -- Halozyme Therapeutics, Inc. (NASDAQ: HALO) today announced results from a Phase 1b trial of PEGPH20 (PEGylated Recombinant Human Hyaluronidase), an investigational new biologic, in combination with gemcitabine for the treatment of patients with stage IV metastatic pancreatic cancer. The full data will be presented today at the 2013 American Society of Clinical Oncology (ASCO) Annual Meeting in a poster session from 1:15 PM-5:15 PM CDT and during a discussion session from 4:45 PM-5:45 PM CDT (E Hall D1, Abstract #4010).

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In this single-arm Phase 1b trial, the overall response rate (complete response + partial response) by RECIST 1.1 criteria was 42 percent (95% CI 22 - 62) for those treated at therapeutic dose levels of PEGPH20 (1.6 and 3.0 µg/kg) as assessed by an independent radiology review (n=24). Additionally, in subjects with high levels of hyaluronan (HA), a substance found in a protective matrix that surrounds many pancreatic cancers, the overall response rate was 64 percent (7 of 11 subjects with available biopsy). Moreover, 43 percent (6 of 14 subjects) saw a reduction of at least 70 percent in serum carbohydrate antigen 19-9 (CA 19-9), a biomarker which often correlates with tumor cell burden.¹

"Targeting the protective tumor matrix with an enzyme that digests hyaluronan is a novel treatment strategy for solid tumors. In addition to enabling chemotherapy drugs to penetrate more effectively into the tumor, removing hyaluronan may also slow its growth," said lead investigator Sunil Hingorani, M.D., Ph.D., Associate Member of the Clinical Research and Public Health Divisions at Fred Hutchinson Cancer Research Center. "Pancreatic cancer is one of the most challenging cancers to treat. We are encouraged by these early stage clinical data, and look forward to further testing the potential of PEGPH20 in randomized trials in combination with the most active regimens available for patients today."

Halozyme announced in April the initiation of a Phase 2 study, a multicenter, randomized clinical trial evaluating PEGPH20 in combination with nab-paclitaxel and gemcitabine for the treatment of stage IV pancreatic cancer. Halozyme is also developing a HA diagnostic tool to evaluate potential treatment benefit based on tumor HA levels for use in the randomized Phase 2 trial. This HA-diagnostic approach may also enable the testing of PEGPH20 in other HA-rich tumor types.

Additional Study Details
In the study, 28 stage IV treatment naïve pancreatic ductal adenocarcinoma patients with primary tumor located at head, body and tail were enrolled. Treatment was generally well tolerated, and the adverse event profile was consistent with those seen in previous studies of PEGPH20 as a single agent and as previously reported for gemcitabine alone. The most common adverse events for PEGPH20 were muscle spasms, myalgia and arthralgia (all grade 1/2). There was no evidence of new toxicities when used in combination with gemcitabine. Responses were observed in patients with lesions in all locations of the pancreas. The pharmacokinetics of PEGPH20 with gemcitabine were consistent with the pharmacokinetics of PEGPH20 as a single agent. Additionally, the pharmacodynamics results support the dosing regimen of PEGPH20 at 3µg/kg, which is being used in the Phase 2 trial.

About PEGPH20
Emerging data show that most pancreatic cancers surround themselves with a protective hyaluronan-rich matrix, which makes the disease difficult to treat and is itself an indicator of poor prognosis. PEGPH20 has been shown to deplete this matrix component from the tumor and rapidly changes the tumor microenvironment and metabolism, which may render it more vulnerable to therapy as well as inhibit tumor growth.

About Pancreatic Cancer
In most patients diagnosed with metastatic pancreatic adenocarcinoma, survival rates are the lowest of any cancer. In 2013, it is estimated that almost 45,000 new cases of pancreatic cancer will be diagnosed. About one-in-78 people in the U.S. will develop the disease, affecting equal numbers of men and women, almost always after the age of 45. Its tendency to spread prior to diagnosis makes it the fourth deadliest cancer with a less than six percent five-year relative survival rate, with more than 38,000 people succumbing to the disease each year.^2-3

About Halozyme
Halozyme Therapeutics is a biopharmaceutical company dedicated to developing and commercializing innovative products that advance patient care. With a diversified portfolio of enzymes that target the extracellular matrix, the Company's research focuses primarily on a family of human enzymes, known as hyaluronidases, which increase the absorption and dispersion of biologics, drugs and fluids. Halozyme's pipeline addresses therapeutic areas, including diabetes, oncology and dermatology that have significant unmet medical need. The Company markets Hylenex^® recombinant (hyaluronidase human injection) and has partnerships with Roche, Pfizer, Baxter, ViroPharma and Intrexon. Halozyme is headquartered in San Diego, CA. For more information on how we are innovating, please visit our corporate website at 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 possible benefits and attributes of PEGPH20, the possible method of action of PEGPH20, the development of the HA diagnostic tool and the potential uses of such tool and the possible utility of PEGPH20 in pancreatic cancer and other tumors. The forward-looking statements are usually (but not always) 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 risks and uncertainties including clinical trial enrollment and results, regulatory approval requirements, unexpected expenditures and costs, unexpected results or delays in development and regulatory review, unexpected adverse events and competitive conditions. These and other factors that may result in differences are discussed in greater detail in the Company's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on May 8, 2013. Halozyme does not undertake to update these forward-looking statements.

References
1. Pancreatic Cancer Treatment, National Cancer Institute, http://www.cancer.gov/cancertopics/pdq/treatment/pancreatic/HealthProfessional/page1/AllPages, Accessed May 21, 2013
2. American Cancer Society, Cancer Facts & Figures 2013. Atlanta: American Cancer Society; 2013.
3. Pancreatic Cancer, American Cancer Society, http://www.cancer.org/cancer/pancreaticcancer/detailedguide/pancreatic-cancer-key-statistics Accessed April 18, 2013.

Investor Contact:
David Ramsay
Halozyme Therapeutics
858-704-8260
ir@halozyme.com

Media Contact:
Nurha Hindi
Hill+Knowlton Strategies
310-633-9434
Nurha.Hindi@hkstrategies.com

SOURCE Halozyme Therapeutics, Inc.