Patient-reported outcomes with olaparib plus abiraterone versus placebo plus abiraterone for metastatic castration-resistant prostate cancer: a randomised, double-blind, phase 2 trial

Results of this double-blind, phase 2 trial showed patients with metastatic castration-resistant prostate cancer given olaparib plus abiraterone versus placebo plus abiraterone had significantly improved progression-free survival. Here, we present an exploratory analysis of pain and health-related quality of life (HRQOL). This double-blind, randomised, placebo-controlled, phase 2 trial was conducted across 41 urological oncology sites in 11 countries in Europe and North America. Eligible patients were aged 18 years or older, had metastatic castration-resistant prostate cancer, and had previously received docetaxel and up to one additional line of previous chemotherapy. Metastatic castration-resistant prostate cancer was defined as increasing prostate-specific antigen (PSA) concentration or other signs of disease progression despite androgen-deprivation therapy and serum testosterone concentrations at castrate levels (≤50 ng/dL), and with at least one metastatic lesion on bone scan, CT, or MRI. Eligible patients were randomly assigned (1:1) to receive oral olaparib (300 mg twice per day) plus oral abiraterone (1000 mg once a day) and oral prednisone or prednisolone (5 mg twice a day) or placebo plus abiraterone (1000 mg once a day) and prednisone or prednisolone (5 mg twice a day). Randomisation was done without stratification and by use of an interactive voice or web response system. A randomised treatment kit ID number was assigned sequentially to each patient as they became eligible. The primary endpoint (radiographic progression-free survival) has previously been reported. HRQOL was a prespecified exploratory patient-reported outcome. Patients were asked to complete the Brief Pain Inventory-Short Form (BPI-SF), single-item worst bone pain, Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire, and EuroQol-5 five-dimension five level (EQ-5D-5L) assessment at baseline, at weeks 4, 8, and 12, then every 12 weeks until treatment discontinuation. Prespecified outcomes were change from baseline in BPI-SF worst pain, single-item worst bone pain and FACT-P Total Outcome Index (TOI) scale scores, time to deterioration in BPI-SF worst pain and worst bone pain, and assessment of the EQ-5D-5L pain and discomfort domain. All analyses were exploratory and done in the full analysis set (all randomly assigned patients, including patients who were randomly assigned but did not subsequently go on to receive study treatment), with the exception of mean b