Pancreatic cancer has one of the highest mortality rates among all cancers and is expected to cause an estimated 37,390 deaths in the United States in 2012. See American Cancer Society, Cancer Facts and Figures 2012. For all stages of pancreatic cancer combined, the 1- and 5-year relative survival rates are 26% and 6%, respectively; this high mortality rate from pancreatic cancer is, at least in part, due to the high incidence of metastatic disease at the time of diagnosis. See id. As a result, treatment options for pancreatic cancer are very limited.
The standard first-line treatment for treating pancreatic cancer is gemcitabine (e.g., GEMZAR®), which was approved by the Food and Drug Administration (“FDA”) in 1996. In a clinical study with 126 patients with locally advanced pancreatic cancer (63 treated with gemcitabine), gemcitabine was shown to be superior to 5-fluororuracil (5-FU) in terms of median overall survival (5.7 months for gemcitabine versus 4.2 months for 5-FU), median time to disease progression (2.1 months for gemcitabine versus 0.9 months for 5-FU), and clinical benefit responses. However, although gemcitabine has become a standard palliative therapy for treating pancreatic cancer since its approval in 1996, there has been little improvement in pancreatic cancer treatment.
The gemcitabine/erlotinib combination improved the median overall survival (6.4 months versus 6.0 months) and median progression free survival (3.8 months versus 3.5 months) over gemcitabine monotherapy. See Moore et al., J. Clin. Oncol. 25:1960-1966 (2007). Based on this very modest improvement in overall survival and progression free survival (0.4 and 0.3 months, respectively), the FDA approved the gemcitabine/erlotinib combination in 2005. Despite its approval, the gemcitabine/erlotinib combination has not been widely used as a standard of care for treating pancreatic cancer because of side effects associated with the gemcitabine/erlotinib combination and the minimal improvement on survival over gemcitabine monotherapy. See Nieto et al., The Oncologist, 13:562-576 (2008).
Albumin-based nanoparticle compositions have been developed as a drug delivery system for delivering substantially water insoluble drugs such as a taxanes. See, for example, U.S. Pat. Nos. 5,916,596; 6,506,405; 6,749,868, and 6,537,579, 7,820,788, and 7,923,536. Abraxane®, an albumin stabilized nanoparticle formulation of paclitaxel, was approved in the United States in 2005 and subsequently in various other countries for treating metastatic breast cancer. It was recently approved for treating non-small cell lung cancer in the United States, and has also shown therapeutic efficacy in various clinical trials for treating difficult-to-treat cancers such as pancreatic cancer and melanoma. Albumin derived from human blood has been used for the manufacture of Abraxane® as well as various other albumin-based nanoparticle compositions.
Albumin bound paclitaxel (e.g., Abraxane®) in combination with gemcitabine was found to be well tolerated in advanced pancreatic cancer in a Phase I/II study and showed evidence of antitumor activity. See, for example, US Patent App.; No. 2006/0263434; Maitra et al., Mol. Cancer Ther. 8(12 Suppl): C246 (2009); Loehr et al., J. of Clinical Oncology 27 (15S) (May 20 Supplement): 200, Abstract No. 4526 (2009); Von Hoff et al., J. of Clinical Oncology 27(15S) (May 20 Supplement), Abstract No. 4525 (2009); and Kim et al., Proc. Amer. Assoc. Cancer Res., 46, Abstract No. 1440 (2005).
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