This study evaluates the use of chemotherapy with cabazitaxel in addition to abiraterone acetate, prednisone, and leuprolide in neoadjuvant setting prior to radical prostatectomy in patients with high-risk prostate carcinoma. Half of the participants will receive treatment with abiraterone acetate, prednisone, leuprolide, and cabazitaxel, while the other half will receive only abiraterone acetate, prednisone, and leuprolide.

Inclusion Criteria:

• Willing and able to provide informed consent;
• Histologically confirmed adenocarcinoma of the prostate without neuroendocrine differentiation or small cell features with a minimum of 3 cores positive for tumour;
• Tumour biopsy tissue accessible for downstream evaluation;
• Must be candidates for radical prostatectomy and considered surgically resectable by urologic evaluation;
• High Risk D'Amico score defined as either PSA > 20, Gleason score ≥ 8 as determined by the local pathologist; or T2c-3 based on DRE, pathologic review +/- imaging;
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1;
• No evidence of metastatic disease or nodal disease as determined by radionuclide bone scans and computed tomography (CT)/magnetic resonance imaging (MRI); non-pathological lymph nodes must be less than 15 mm in the short (transverse) axis;
• Able to swallow the study drug(s) as prescribed and comply with study requirements;
• Required initial laboratory values:
• Absolute neutrophil count (ANC) ≥ 1500/μL;
• Platelet count ≥ 100,000/μL;
• Hemoglobin ≥ 90 g/L;
• Creatinine ≤ 175 μmol/L;
• Bilirubin ≤ upper limit of institutional normal (ULN);
• AST/ALT ≤ 1.5 × ULN.

Exclusion Criteria:

• Received an investigational agent within 4 weeks prior to screening;
• Stage T4 prostate cancer by clinical examination or radiologic evaluation;
• Hypogonadism or severe androgen deficiency as defined by screening serum testosterone below the normal range for the institution;
• Prior androgen deprivation, chemotherapy, surgery, or radiation for prostate cancer;
• Receiving concurrent androgens, estrogens, or progestational agents, or received any of these agents within the 6 months prior to randomization;
• History of another malignancy within the previous 5 years other than curatively treated nonmelanomatous skin cancer and non-muscle invasive bladder cancer;
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, cardiovascular disease, unstable angina pectoris, cardiac arrhythmia that is symptomatic or requires active therapy; deep venous thrombosis within 3 months prior to randomization;
• Previous use, or participation in a clinical trial, of an investigational agent that blocks androgen synthesis (e.g., abiraterone acetate, TAK-700, TAK-683, TAK-448) or targets the androgen receptor (e.g., enzalutamide, BMS 641988);
• Liver injury or disease (e.g., viral hepatitis, liver failure Child-Pugh Class C).