Abiraterone Acetate and Prednisone With or Without Dasatinib in Treating Patients With Metastatic Hormone-Resistant Prostate Cancer

PRIMARY OBJECTIVES: I. To compare the progression-free survival of men with metastatic castration-resistant prostate cancer treated with abiraterone (abiraterone acetate) plus dasatinib to that of men treated with abiraterone alone. SECONDARY OBJECTIVES: I. To describe the toxicity profile of the combination, as well as the rate of prostate-specific antigen (PSA) response, objective responses, and changes in circulating tumor cell (CTC) numbers. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM A: Patients receive abiraterone acetate 1000 mg orally (PO) once daily (QD) and prednisone 5 mg PO twice daily (BID) on days 1-28. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity. ARM B: Patients receive abiraterone acetate and prednisone as patients in arm A. Patients also receive dasatinib 100 mg PO QD on days 1-28. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up periodically.