Pfizer Inc. announced the discontinuation of the SUN 1120 phase 3 trial evaluating Sutent (sunitinib malate) 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 tumour (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 3 clinical trials. Sutent has played a significant role in advancing the treatment landscape and remains a standard of care in its approved indications. To date, more than 91,000 patients have been treated with sunitinib worldwide.

Pfizer is evaluating the potential role of sunitinib for the adjuvant treatment of renal cell carcinoma in a phase 3 trial.

Sutent is an oral multi-kinase inhibitor approved for the treatment of advanced RCC and for the treatment of GIST after disease progression on or intolerance to imatinib mesylate.

Sutent works by blocking multiple molecular targets implicated in the growth, proliferation and spread of cancer. Two important Sutent targets, vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR), are expressed by many types of solid tumours and are thought to play a crucial role in angiogenesis, the process by which tumours acquire blood vessels, oxygen and nutrients needed for growth. Sutent also inhibits other targets important to tumour growth, including KIT, FLT3 and RET.