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Clinical Trial 19840

Cancer Type: Genitourinary
Interventions:Abiraterone acetate; CPI-1205; Enzalutamide; Zytiga (Abiraterone acetate); cobicistat; prednisone

Study Type: Treatment
Phase of Study: Phase I/II

  • Jingsong Zhang

Call 813-745-6100
or 1-800-679-0775

Study Title

ProSTAR: A Phase 1b/2 Study of CPI-1205, a Small Molecule Inhibitor of EZH2, Combined with Enzalutamide or Abiraterone/Prednisone in Patients with Metastatic Castration Resistant Prostate Cancer



Phase 1b Dose Escalation Primary Objective: To determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of CPI-1205 + enzalutamide and CPI-1205 + abiraterone/prednisone in patients with metastatic castration resistant prostate cancer (mCRPC). Phase 1b HPEC(s) Primary Objective: To estimate objective response rate (ORR) as determined by central radiology review (CRR) of CPI-1205 (with or without cobicistat) + enzalutamide OR abiraterone/prednisone in the HPEC. Randomized Phase 2 Primary Objective: To evaluate the effect of CPI-1205 (with or without cobicistat) + enzalutamide OR abiraterone/prednisone (combination arm) versus(vs) enzalutamide OR abiraterone/prednisone alone (control arm) in patients with mCRPC.

Inclusion Criteria

  • Adults (Age ≥ 18 years)
  • Eastern Cooperative Oncology Group (ECOG) performance status 0-1
  • Life expectancy of at least 12 weeks
  • Histologically or cytologically confirmed adenocarcinoma of the prostate
  • Progressive disease in the setting of medical or surgical castration (i.e. CRPC)
  • Documented metastatic disease
  • Must have undergone bilateral orchiectomy (surgical castration) or be willing to continue gonadotropin-releasing hormone (GnRH) analog or antagonist (medical castration)
  • Serum testosterone >Receipt of prior line of second generation androgen inhibitor
  • Demonstrate adequate organ function as defined below:
  • Absolute Neutrophil Count (ANC) ≥ 1,000/μL
  • Platelet Count ≥ 100,000/μL
  • Hemoglobin (Hgb) ≥ 8 g/dL
  • Serum creatinine ≤ 2 × upper limit of normal (ULN) OR
  • Creatinine clearance (CrCl) ≥ 40 mL/min as estimated by the Cockcroft and Gault formula1 in subjects with creatinine > 2 X ULN
  • Bilirubin ≤ 1.5 × ULN unless evidence of Gilbert's disease in which case >Aspartate aminotransferase (AST) ≤ 2.5 × ULN without liver metastases; must be ≤ 5 × ULN with liver metastases
  • Alanine aminotransferase (ALT) ≤ 2.5 × ULN without liver metastases; must be ≤ 5 × ULN with liver metastases

  • Exclusion Criteria

  • Known symptomatic brain metastases (NOTE: patients with treated epidural disease are allowed)
  • Treatment with any of the following for prostate cancer within the indicated timeframe prior to day 1 of treatment:
  • First generation: AR antagonists (e.g., bicalutamide, nilutamide, flutamide) within 4 weeks
  • 5 alpha reductase inhibitors, ketoconazole, estrogens (including diethylstilbesterol [DES]), or progesterones within 2 weeks
  • Chemotherapy within 3 weeks
  • Biologic therapy within 4 weeks
  • Investigational therapy within 3 weeks (or within a time interval less than at least 5 half-lives of the investigational agent [if known], whichever is longer).
  • Immunotherapy within 4 weeks
  • Prior radionuclide therapy within 4 weeks