SAN DIEGO, May 15, 2013 /PRNewswire/ -- Halozyme Therapeutics, Inc. (NASDAQ: HALO) today announced that clinical data from a Phase 1b trial of PEGPH20 (PEGylated Recombinant Human Hyaluronidase), an investigational new biologic, in combination with gemcitabine for treatment of patients with stage IV metastatic pancreatic cancer will be presented at the 2013 American Society of Clinical Oncology (ASCO) Annual Meeting. (Logo: http://photos.prnewswire.com/prnh/20100302/LA63139LOGO) In this Phase 1b study, 28 stage IV pancreatic ductal adenocarcinoma patients were treated with PEGPH20 in combination with gemcitabine. The overall response rate (CR+PR) was 42 percent* (n=24) as assessed by independent review at therapeutic dose levels of PEGPH20 (1.6 and 3.0 µg/kg). 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. There was no evidence of new observed toxicity. Detailed clinical data, including CA 19-9 and pharmacodynamic results will be presented at the meeting. 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 depletes 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. "Data from this single arm Phase 1b study clearly reinforce the hypothesis of treating pancreatic cancer with PEGPH20 in conjunction with chemotherapeutic agents," said Joy Zhu, M.D., Ph.D., Vice President, Oncology Clinical Development, Halozyme. "We look forward to the study investigators presenting the updated study results at the poster session and ensuing discussion." Based on the magnitude of response and safety observed in the Phase 1b study, Halozyme announced in April the initiation of a Phase 2 multicenter, randomized clinical trial evaluating PEGPH20 as a first-line therapy for patients with stage IV metastatic pancreatic cancer. Approximately 124 patients will participate in the study and receive gemcitabine and nab-paclitaxel either with or without PEGPH20. Secondary endpoints of the trial include clinical evaluation of patient response in both treatment arms by tumor biopsy hyaluronan (HA) status.