Inclusion Criteria:

          -  Patients must have castrate refractory prostate cancer with prior taxane treatment
             (docetaxel or cabazitaxel) which was used in the castrate refractory setting

          -  Cancer Progression as defined by PCWG3

          -  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 the duration of study participation.

          -  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.