Inclusion Criteria:

          1. Written informed consent obtained prior to any study-related procedure being performed

          2. Male patients at least 18 years of age or older at time of consent

          3. Pathologically confirmed adenocarcinoma of the prostate

          4. Ongoing therapy with a gonadotropin releasing hormone (GnRH) agonist or antagonist
             (unless patient has already had a bilateral orchiectomy) AND serum testosterone level
             <50 ng/dL at screening

          5. Have either metastatic CSPC or metastatic CRPC (per protocol definitions).

          6. The following prior treatments and/or surgery for prostate cancer are allowed:

               1. CSPC:

                    -  Up to 90 days of androgen deprivation therapy (ADT) with
                       gonadotropin-releasing hormone (GnRH) agonists/antagonists or orchiectomy
                       with or without concurrent anti-androgens prior to patients' randomization
                       is permitted

                    -  Patients may have one course of palliative radiation or surgical therapy to
                       treat symptoms resulting from metastatic disease (e.g., impending cord
                       compression or obstructive symptoms) if administered prior to randomization

                    -  Radiation or surgical therapy that was not initiated 4 weeks after the start
                       of ADT or orchiectomy

               2. CRPC:

                    -  Previous chemotherapy with docetaxel for metastatic disease with treatment
                       completed at least 1 year prior to enrolment

          7. Discontinuation of flutamide or nilutamide, and other anti-androgens prior to the
             start of study medication; discontinuation of bicalutamide prior to start of study
             medication

          8. Discontinuation of strong CYP3A4 inducers at prior to start of study medication

          9. Discontinuation of radiotherapy prior to start of study medication

         10. Discontinuation of herbal supplements at least 4 weeks prior to the first dose of
             study medication and for the duration of the trial.

         11. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2 at screening

         12. Normal organ function with acceptable initial laboratory values within the screening
             period:

               -  ANC: ≥ 1,500/μl

               -  Albumin: ≥ 3.0g/dL

               -  Hemoglobin: ≥ 9g/dL

               -  Platelet count: ≥ 100,000/μl

               -  Serum Creatinine: ≤ 3.0 x the institutional upper limit of normal (ULN)

               -  Potassium: ≥ 3.5 mmol/L (within institutional normal range)

               -  Bilirubin: ≤ 1.5 ULN (unless documented Gilbert's disease)

               -  SGOT (AST): ≤ 2.5 x ULN

               -  SGPT (ALT): ≤ 2.5 x ULN

         13. Life expectancy of at least 6 months at screening

         14. Patients engaged in sex with women of child-bearing potential agree to use a condom
             plus another effective contraception method. Patients agree to use a condom when
             engaged in any sexual activity, including sex with a pregnant woman. These
             restrictions will apply from the time informed consent is provided until 3 weeks after
             the last dose of study medication is taken.

         15. Patient is willing and able to comply with all protocol requirements

        Exclusion Criteria:

          1. For mCSPC patients: any prior pharmacotherapy, radiation therapy, or surgery for
             metastatic prostate cancer not specified as allowable treatment in Inclusion Criterion
             6. For example, prior therapy with apalutamide or enzalutamide is prohibited as well
             as therapy with an investigational agent as described in Exclusion Criterion 16.

          2. For mCRPC patients:

               -  Prior treatment with abiraterone or enzalutamide is prohibited

               -  Previous chemotherapy is prohibited with exception of docetaxel treatment as
                  specified in the inclusion criteria 6.

          3. Initiation of bisphosphonate or denosumab therapy within 4 weeks prior to the start of
             study drug/reference product. Patients who are on a stable dose of these medications
             for at least 4 weeks at the time of starting study drug/reference product will be
             eligible.

          4. Therapy with estrogen within 4 weeks prior to the start of study drug

          5. Use of systemic glucocorticoids equivalent to >10 mg prednisone daily. Patients who
             have discontinued or reduced dosing to the equivalent of ≤ 10 mg prednisone daily
             within 14 days prior to the start of study drug are eligible

          6. Known, symptomatic metastases to the brain or central nervous system involvement
             (patients with asymptomatic and neurologically stable disease for the past 4 weeks
             will be permitted)

          7. History of adrenal gland dysfunction defined as requiring treatment for adrenal
             insufficiency

          8. History of other malignancy within the previous 2 years (no longer being actively
             treated), with the exceptions of basal cell carcinoma, nonmuscle invasive bladder
             cancer that has been treated and is under surveillance, or other in-situ cancers with
             a low likelihood of recurrence

          9. Major surgery within 4 weeks prior to the start of study drug

         10. Known gastrointestinal disease or condition that could impair absorption inclusive of
             gastrocolic fistula, gastroenterostomy, biliary obstruction, cirrhosis, chronic
             pancreatitis or pancreatic cancer, cystic fibrosis, lactate deficiency, amyloidosis,
             celiac disease, Crohn's disease, radiation enteritis, intestinal resection, and
             history of bariatric surgery

         11. Known history of human immunodeficiency virus or seropositive test for hepatitis C
             virus (HCV) or hepatitis B surface antigen (HBsAg) (note: HCV patients with
             undetectable viral load will be eligible)

         12. Poorly controlled diabetes, defined as HbA1c > 8% within the past 12 months

         13. Uncontrolled hypertension at screening

         14. History of New York Heart Association class III or IV heart failure

         15. Serious concurrent illness, including psychiatric illness, that could interfere with
             study participation

         16. Receipt of another investigational agent within 4 weeks or 5 x the treatment
             half-life, whichever is longer, of treatment start.

         17. Known hypersensitivity or allergy to abiraterone acetate, prednisone or any excipients
             in the study drugs

         18. In the opinion of the investigator, participation in the trial would prevent the
             patient from receiving local standard-of-care treatment for metastatic prostate
             cancer, if clinically indicated, after completion of the trial

         19. Other condition which, in the opinion of the Investigator, would preclude
             participation in this trial.