Updated survival data from Phase I/II trial of nab-paclitaxel, gemcitabine combination for pancreatic cancer

Apr 19 2010

Abraxis BioScience, Inc. (NASDAQ:ABII), a fully integrated biotechnology company, today announced updated overall survival findings from a phase I/II study of nab^®-paclitaxel (ABRAXANE^® for Injectable Suspension) (paclitaxel protein-bound particles for injectable suspension) (albumin-bound) given in combination with gemcitabine, demonstrated increased survival of the first-line treatment of patients with advanced pancreatic cancer. In 44 patients treated at the recommended dose of 125 mg/m² nab-paclitaxel plus gemcitabine (1000 mg/m²), the median overall survival (OS) time was 12.2 months, a doubling of survival compared to historical control of gemcitabine administered alone. This combination of nab-paclitaxel and gemcitabine also resulted in a confirmed overall response rate in 50 percent of patients treated, and a disease control rate (CR, PR and stable disease for 16 weeks or longer according to RECIST criteria) of 68 percent. In the overall studyEpithelium and Stroma: Double Trouble," during the "Progress in Pancreatic Cancer" session on April 18 at the 101^st Annual Meeting of the American Association for Cancer Research (AACR) being held in Washington, D.C.

"The results of this study demonstrate that the combination of nab-paclitaxel and gemcitabine at the recommended dose of 125 mg/m² nab-paclitaxel has substantial antitumor activity. One hundred percent of the patients in the 125 mg/m² nab-paclitaxel arm>" said Daniel Von Hoff, M.D., F.A.C.P., Physician-in-Chief, Senior Investigator, Translational Genomics Research Institute (TGen); Clinical Professor of Medicine, University of Arizona; and Chief Scientific Officer, Scottsdale Healthcare and U.S. Oncology Research.

The biomarker CA19-9 is a tumour-associated antigen that has been shown to be a highly specific and sensitive for pancreatic cancer; approximately three-quarters of all pancreatic cancer patients have elevated baseline serum CA19-9 level at baseline. Of the 54 patients in the trial interrogated for CA 19-9, 69 percent had a greater than 70 percent decrease in levels of the biomarker, which correlated to a median overall survival of 15.6 months in this subset.

"The mechanism of transport of ABRAXANE is believed to exploit the albumin-binding protein receptor Gp-60 in the blood vessel wall, opening a portal to the tumor micro-environment through the Gp-60/Caveolin-1 transcytosis pathway. By creating this highway from the blood to the tumor microenvironment, the potential thus exists to deliver a high concentration of paclitaxel as well as other cytotoxic agents given in combination with nab-paclitaxel to this site, thereby achieving stromal collapse and high intra-tumoral drug concentration. This portal to the microenvironment may create a new paradigm for the treatment of solid tumors by potentially establishing a capability for enhanced delivery of cytotoxics when given in combination with nab-paclitaxel," said Patrick Soon-Shiong, M.D., Executive Chairman and founder of Abraxis BioScience.

The updated survival data follow interim data from the Phase I/II pancreatic clinical trial presented at the 45^th Annual Meeting of the American Society of Clinical Oncology. The combination of nab-paclitaxel (125mg/m²) and gemcitabine (1000 mg/m²) is now the treatment arm of a randomized Phase 3 clinical trial that is currently enrolling patients.

Pancreatic cancer is particularly difficult to treat because many patients are diagnosed after their disease has progressed. This year, more than 42,000 people are expected to be diagnosed with pancreatic cancer in the United States and more than 35,000 people will die from the disease. Recent research indicates that an exceptionally dense stroma around pancreatic tumors contributes to treatment difficulty, and that delivery systems that can break through this surrounding mass may deliver more drug to the cells and improve outcome.

ABRAXANE is currently approved for the treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within six months of adjuvant chemotherapy. Prior therapy should have included an anthracycline unless clinically contraindicated. ABRAXANE has also been granted orphan drug designation by the Food and Drug Administration for the treatment of pancreatic cancer as well as stage IIB-IV melanoma.

Source Abraxis BioScience, Inc.