OGX-427 in Metastatic Castrate-Resistant Prostate Cancer With Prostate-Specific Antigen Progression While Receiving Abiraterone

OUTLINE: This is a multi-center study. This is an open-label, randomized, Phase II clinical trial designed to evaluate the anti-tumor effects of OGX-427 and continuing abiraterone acetate and prednisone versus continuing abiraterone acetate and prednisone alone in men with MCRPC who have evidence of PSA progression but no evidence of symptomatic or radiographic progression that would require alternative therapy (e.g., needing radiation therapy for pain or significant progression of visceral metastases). Patients on the control arm will be allowed to cross-over to receive OGX-427 following documented disease progression. Patients will be randomized with equal probability to one of the following arms: EXPERIMENTAL ARM (Arm A): OGX-427 Starting within 7 days of randomization, three loading doses of 600 mg intravenously (IV) within Week 1 if possible (up to 10 days of initiating treatment), followed by weekly doses of 800 mg IV Continuation of standard therapy with abiraterone acetate 1000 mg by mouth (PO) daily and prednisone 10-20 mg PO daily CONTROL ARM (Arm B): Continuation of standard therapy with abiraterone acetate 1000 mg PO daily and prednisone 10-20 mg PO daily After documented disease progression, patients on Arm B may opt to receive OGX-427 treatment (according to the Arm A schedule) following a screening evaluation (i.e., all inclusion and exclusion criteria have been met) Both Arms: Evaluations at 4 week-intervals. Disease assessments required at the milestone Day 60 assessment (expected to occur after 8 weeks of treatment and prior to Day 1, Week 9) and at 16, 24, 32, 40, and 48 weeks (if applicable) or until documented disease progression. Patients who are withdrawn from the study for a reason other than documented disease progression or patient withdrawal of consent will be followed every 4 weeks in the Off-Treatment Follow-up Period until documented disease progression. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 Life Expectancy: Not Specified Hematopoietic: * Absolute neutrophil count (ANC) ≥ 1.5 x 109 cells /L, platelet count ≥ 100 x 109 /L, and hemoglobin ≥ 9 g/dL without transfusion Hepatic: * Total bilirubin ≤ 1.1 x upper limit of normal (ULN) unless elevated secondary to conditions such as Gilbert's disease, in which case a direct bilirubin ≤ ULN is required * Serum glutamic pyruvic transaminase (SGPT), alanine transaminase (ALT) and alanine transaminase (SGOT) aspartate transaminase (AST) ≤ 3.0 x ULN Renal: * Creatinine ≤ 1.3 x ULN Cardiac: * Known left ventricular ejection fraction (LVEF) \<50% or New York Heart Association (NYHA) Functional Classification Class III or IV heart failure Other: * Castrate serum testosterone level (\< 50 ng/dL or \< 1.7 nmol/L) * Potassium within normal limits