CASCARA: Castration Sensitive Carboplatin, Cabazitaxel and Abiraterone

Inclusion criteria

• Willing and able to provide, or have a legally authorized representative provide, written informed consent and HIPAA authorization for the release of personal health information. A signed informed consent must be obtained before screening procedures are performed.
• Histologically confirmed prostate cancer.
• High volume metastatic disease (defined as the presence of visceral metastases or ≥3 bone lesions).
• ADT for ≤3 months by day 1 of study chemotherapy; Prior episodes of ADT are allowed (i.e. ADT used previously in courses of radiation).
• Testosterone <50 ng/dL. Patients must continue primary ADT with an LHRH analogue if they have not undergone orchiectomy.
• ECOG Performance Status 0 or 1 (see Appendix A)
• Patient has adequate bone marrow and organ function as defined by the following laboratory values:

• Absolute neutrophil count ≥ 1.5 × 10^9/L
• Platelets ≥ 100 × 10^9/L
• Hemoglobin ≥ 9 g/dl
• Serum creatinine ≤ 1.5mg/dL or estimated creatinine clearance ≥ 50 ml/min
• In the absence of liver metastases, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) <2.5 x ULN. If the patient has liver metastases, ALT and AST <5 x ULN
• Total bilirubin < ULN; or total bilirubin ≤3.0 x ULN or direct bilirubin ≤1.5 x ULN in patients with well-documented Gilbert's Syndrome.
• Sexually active males must use a condom during intercourse while taking study drugs and for 30 days after stopping treatment and should not father a child in this period. A condom is required to be used also by vasectomized men in order to prevent delivery of the drug via seminal fluid. Fertile males must use a condom with spermicide (double barrier method).
• Age ≥ 18 years

Exclusion criteria

• Prior exposure to any chemotherapy, PARPi, or immunotherapy for prostate cancer.
• Prior abiraterone or enzalutamide, unless therapy was for < 2 weeks
• Radiation therapy (including palliative radiotherapy to a metastatic lesion) within 14 days or major surgery (e.g., open abdominal, pelvic, thoracic, orthopedic or neurosurgery) within 28 days of the date of the first dose.
• Other systemic therapies for prostate cancer within 28 days or 5 half-lives, whichever is shorter, prior to day 1 of chemotherapy (with the exception of anti-androgens like bicalutamide).
• PSA <2.0 ng/mL at diagnosis.
• If present, peripheral neuropathy must be ≤ Grade 1
• Patients with an active second malignancy that could, in the investigator's opinion, potentially interfere with the patient's ability to participate and/or complete this trial.
• Patients with central nervous system (CNS) involvement unless they meet ALL of the following criteria:

• At least 4 weeks from prior therapy completion (including radiation and/or surgery) prior to starting the study treatment
• Clinically stable CNS tumor at the time of screening.
• Baseline screening for CNS metastases is not required unless presence of signs and/or symptoms of involvement
• Patients with severe psychiatric illness/social situations that would limit compliance with study requirements in the judgment of treating investigator.
• Patient has a history of non-compliance to medical regimen or inability to grant consent.