Zytiga abiraterone acetate: Phase II data

An open-label, U.S. Phase II trial in 58 men with localized high-risk prostate cancer who were candidates for radical prostatectomy showed that neoadjuvant therapy with Zytiga plus leuprolide and prednisone for 24 weeks prior to surgery led to a pathological CR in 3 of 29 patients (10%) vs. 1 of 27 patients (4%) who received leuprolide alone for 12 weeks followed by Zytiga plus leuprolide and prednisone for an additional 12 weeks before surgery (p=0.3349). Additionally, 7 and 3 patients, respectively, achieved a near pCR defined as a residual tumor size of <=5 mm (p=0.2034). At week 12, a significantly greater proportion of patients who received Zytiga plus leuprolide and prednisone achieved PSA levels of <=0.2 ng/mL vs. patients who received leuprolide alone (90% vs. 4%, p<0.0001). At week 24, 86% of patients who received Zytiga plus leuprolide and prednisone for 24 weeks achieved PSA levels of <=0.2 ng/mL vs. 85% of patients who received leuprolide alone for 12 weeks followed by 12 weeks of Zytiga plus leuprolide and prednisone (p=0.9131). Neoadjuvant therapy with Zytiga was well tolerated. Data will be presented at the American Society of Clinical Oncology meeting in Chicago in June. ...