Blood marker may predict prostate cancer drug response

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Signed informed consent. * Age ≥18 years and male * Histologically or cytologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation or small cell histology * Received at least one but not more than two cytotoxic chemotherapy regimens for metastatic CRPC. At least one regimen must have contained a taxane such as docetaxel. * Prostate cancer progression as assessed by the investigator with one of the following: * PSA progression according to Prostate Cancer Working Group 2 (PCWG2) criteria * Solid Tumors (RECIST) criteria or bone scans with or without PSA progression. * Radiographic progression in soft tissue according to Response Evaluation Criteria in * Ongoing androgen deprivation with serum testosterone \<2.0 nM * Eastern Cooperative Oncology Group (ECOG) performance status of ≤2 * Platelet count ≥100,000/μL * Serum albumin ≥30 g/dL * Serum creatinine \<1.5 x upper limit of normal (ULN) or a calculated creatinine clearance ≥ 60 mL/min * Serum potassium ≥3.5 mmol/L Exclusion Criteria: * Received abiraterone or MDV3100 in the past. * Serious or uncontrolled co-existent non-malignant disease, including active and uncontrolled infection. * Abnormal liver functions consisting of any of the following: * Serum bilirubin ≥1.5 x ULN (except for subjects with documented Gilbert's disease, for whom the upper limit of serum bilirubin is 51 µmol/l) * Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) ≥2.5 x ULN * Uncontrolled hypertension (systolic blood pressure ≥160 mmHg or diastolic blood pressure ≥95 mmHg); subjects with a history of hypertension are allowed provided blood pressure is controlled by anti-hypertensive therapy. * Active or symptomatic viral hepatitis or chronic liver disease * History of pituitary or adrenal dysfunction * Clinically significant heart disease as evidenced by myocardial infarction, or arterial thrombotic events in the past 6 months, severe or unstable angina, or New York Heart Association (NYHA) Class III or IV heart disease or left ventricular ejection fraction (LVEF) of \<50% at baseline. * Known brain metastasis * History of gastrointestinal disorders (medical disorders or extensive surgery) that may interfere with the absorption of the study drug * Any acute toxicities due to prior chemotherapy or radiotherapy that have not resolved to a NCI-CTCAE (Version 4.0) Grade of ≤1. Chemotherapy induced alopecia and Grade 2 peripheral neuropathy is allowed. * Use of other anticancer therapy including cytotoxic, radionucleotide, and immunotherapy; diethylstilbestrol; PC-SPES; spironolactone (ie, ALDACTONE, SPIRONOL); and other preparations such as saw palmetto thought to have endocrine effects on prostate cancer, within 4 weeks of Cycle 1 Day 1 * Prior systemic treatment with an azole drug (eg, fluconazole, itraconazole, ketoconazole) within 4 weeks of Cycle 1 Day 1 * Current enrolment in an investigational drug or device study or participation in such a study within 30 days of Day 1 * Condition or situation which, in the investigator's opinion, may put the subjects at significant risk, may confound the study results, or may interfere significantly with subject's participation in the study.