A Randomised, Double-blind, Placebo-controlled, Multicentre Phase III Study of Olaparib Plus Abiraterone Relative to Placebo Plus Abiraterone as First-line Therapy in Men With Metastatic Castration-resistant Prostate Cancer (PROpel Study)


The purpose of this study is to evaluate the efficacy and safety (including evaluating side effects) of combination of olaparib and abiraterone versus placebo and abiraterone in patients with metastatic castration-resistant prostate cancer (mCRPC) who have received no prior cytotoxic chemotherapy or new hormonal agents (NHAs) at metastatic castration-resistant prostate cancer (mCRPC) stage.

Study Arms

  • Experimental: olaparib plus abiraterone
  • Placebo Comparator: placebo plus abiraterone


  • Histologically or cytologically confirmed prostate adenocarcinoma.
  • Metastatic status defined as at least 1 documented metastatic lesion on either a bone scan or a computed tomography(CT)/ magnetic resonance imaging (MRI) scan.
  • First-line metastatic castration-resistant prostate cancer (mCRPC).
  • Ongoing androgen deprivation with gonadotropin-releasing hormone analogue or bilateral orchiectomy, with serum testosterone <50 nanograms per decilitre (ng/dL) (<2.0 nanomoles per litre (nmol/L)) within 28 days before randomisation. Patients receiving androgen deprivation therapy (ADT) at study entry should continue to do so throughout the study.
  • Candidate for abiraterone therapy with documented evidence of progressive disease.
  • Patients must have normal organ and bone marrow function measured within 28 days prior to administration of study treatment.