Earlier today, Pfizer Inc. announced that it has discontinued the SUN 1120 Phase III trial evaluating sunitinib malate (Sutent?), an oral multi-kinase inhibitor, in combination with prednisone for men with advanced castration-resistant prostate cancer (CRPC) that had progressed despite treatment with a docetaxel-based chemotherapy regimen.
During a scheduled interim analysis, an independent Data Monitoring Committee (DMC) found that the combination of sunitinib with prednisone was unlikely to improve overall survival when compared to prednisone alone. No new or unexpected safety issues were identified. The full data set from this trial is being analyzed and will be presented at an upcoming medical meeting.
“This planned interim analysis helped us determine that the combination of sunitinib with prednisone would not ultimately improve the overall survival of men with advanced stage, castration-resistant prostate cancer,”said Dr. Mace Rothenberg, senior vice president of Clinical Development and Medical Affairs, Pfizer Oncology Business Unit. “There is a great need for better therapies for prostate cancer and we are committed to working with basic scientists and clinical researchers to identify more effective treatments for this disease.”
Sunitinib is currently approved for both gastrointestinal stromal tumor (GIST) after disease progression on or intolerance to imatinib mesylate, and advanced/metastatic renal cell carcinoma (RCC), based on efficacy and safety data from large, randomized Phase III clinical trials. Sunitinib remains a standard of care in its approved indications. To date, more than 91,000 patients have been treated with sunitinib worldwide.
Prostate Cancer
Prostate cancer is the most common type of cancer found in American men, other than skin cancer. Prostate cancer is the second leading cause of cancer death in men. (Lung cancer is the first.) One man in 6 will get prostate cancer during his lifetime. And one man in 36 will die of this disease. More than 2 million men in the United States who have had prostate cancer at some point are still alive today. The death rate for prostate cancer is going down, and the disease is being found earlier, too. According to The American Cancer Society’s most recent estimates (2010) about 217,730 men will be diagnosed with prostate cancer and 32,050 men will die from the disease.
Mechanism of Action
Sunitinib works by blocking multiple molecular targets implicated in the growth, proliferation and spread of cancer. Two important targets, vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR), are expressed by many types of solid tumors and are thought to play a crucial role in angiogenesis, the process by which tumors acquire blood vessels, oxygen and nutrients needed for growth. Sunitinib also inhibits other targets important to tumor growth, including KIT, FLT3 and RET.
Renal Cell Carcinoma
Sunitinib is approved for the treatment of advanced renal cell carcinoma and for the treatment of GIST after disease progression on or intolerance to imatinib mesylate. Pfizer is evaluating the potential role of sunitinib for the adjuvant treatment of RCC in a Phase III trial.
