Primary objective:
To compare radiographic progression-free survival (rPFS) and overall survival (OS) with enzalutamide and rucaparib versus enzalutamide alone for patients with metastatic castration resistant prostate cancer commencing first-line therapy.

Secondary objectives:
In patients commencing enzalutamide as the first-line therapy for metastatic castration resistant prostate cancer, to evaluate the effects of concurrent administration of rucaparib on:

  • rPFS and OS within HRR mutant and wild-type patients
  • Time to unequivocal clinical progression
  • Best radiographic response using prostate cancer working group 3 (PCWG3) criteria
  • Duration of overall response
  • PSA response rate
  • Best response by serum PSA by months 7 and 13 using categorical and continuous measures.
  • Time to first symptomatic skeletal event (SSE)
  • Safety and tolerability as measured by NCI Common Toxicity Criteria; trial discontinuation for treatment emergent toxicities

Inclusion Criteria:

  • Histologic/cytologic documentation of prostate adenocarcinoma
  • Adequate archival tumor specimen or archival slides
  • Progressive disease must be demonstrated at study entry while the patient is on continuous androgen deprivation therapy (ADT) or status post orchiectomy
  • Measurable or non-measurable metastatic disease
  • No prior therapy for metastatic castration-resistant prostate cancer
  • >= 2 weeks or 5 half-lives (whichever is shorter) since prior therapy
  • No prior therapy with enzalutamide, rucaparib or any other PARP inhibitor, or platinum chemotherapy
  • Prior docetaxel and/or novel anti-androgen use is allowed only if given in the hormone-sensitive non-metastatic or metastatic, or castration-resistant non-metastatic disease setting
  • Patient must have discontinued all previous treatments for cancer (except ADT and bone anti-responsive therapies such as denosumab or zoledronic acid)
  • Eastern Cooperative Oncology Group (ECOG) performance status 0-2
  • Normal lab values
  • No clinically suspected central nervous system (CNS) (leptomeningeal or parenchymal) metastases
  • No known or suspected history of cytopenia
  • No blood product transfusion, granulocyte/granulocyte-macrophage-colony stimulating factor (G-CSF/GM-CSF), or erythropoietin/thrombopoietin use within 14 days of pre-registration
  • No significant cardiac history
  • No history of seizure or any condition that may increase the patient's seizure risk within 2 years
  • Other inclusion/exclusion criteria are present. Please contact the study team for a complete list.
Clinical Program: Urological Oncology Program
Contact Info: 2029941419