The purpose of this research study is to find out what effects (good and bad) omeprazole and cabazitaxel, or omeprazole and docetaxel, has on participants and their condition. Investigators believe omeprazole may help the other medications work.

Primary Objective(s): Obtain RECIST Overall Response Rate (ORR) of 29% by adding the fatty acid synthase inhibitor, omeprazole to cabazitaxel. ORR defined by partial response (PR) or complete response (CR) in tumor size and bone metastasis

Secondary Objectives (only at patients treated at Wake Forest Baptist Comprehensive Cancer Center main campus):

• Obtain a prostate specific antigen response rate by adding the fatty acid synthase inhibitor omeprazole to cabazitaxel regimen
• Measure pain using the Patient-Reported Outcomes Measurement Information System (PROMIS) at Baseline, Cycle 5, Cycle 12, and every cycle thereafter.

Inclusion Criteria:

• Patients must have castrate refractory prostate cancer with prior docetaxel treatment which was used in the castrate refractory setting
• Cancer Progression as defined by prostate cancer working group 3 (PCWG3) any type- prostate specific antigen only, bone only +nodal, nodal only or new lesions
• Age 18 or older.
• ECOG 0, 1, or 2
• Life expectancy of greater than 2 months
• Men must agree to use adequate contraception (barrier method of birth control; abstinence) prior to study entry and for three (3) months after study treatment discontinuation.
• Ability to understand and the willingness to sign an IRB-approved informed consent document (either directly or via a legally authorized representative).
• Organ & marrow function as defined below: Absolute neutrophil count >1,200/mcL, Platelets >75,000/mcL; total bilirubin = within normal institutional limits; AST(SGOT)/ALT(SGPT) <2.5 X institutional upper limit of normal; creatinine <2.5 X institutional upper limit of normal

Exclusion Criteria:

• Patients may not be receiving any other investigational agents.
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to omeprazole or taxane therapy.
• Uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.