Antitumour Activity and Safety of Enzalutamide in Patients with Metastatic Castration-resistant Prostate Cancer Previously Treated with Abiraterone Acetate Plus Prednisone for ≥24 weeks in Europe.
de Bono, JS
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Background Enzalutamide and abiraterone acetate plus prednisone, which target the androgen receptor axis, have expanded the treatment of advanced prostate cancer. Retrospective analyses suggest some cross-resistance between these two drugs when used sequentially, but robust, prospective studies have not yet been reported.Objective To fulfil a regulatory postregistration commitment by evaluating the efficacy and safety of enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) who progressed following abiraterone acetate plus prednisone treatment.Design, setting, and participants Multicentre, single-arm, open-label study, enrolled patients with progressing mCRPC after ≥24 wk of abiraterone acetate plus prednisone treatment. All patients maintained castration therapy during the trial. Prior chemotherapy was allowed but not required.Intervention Patients received enzalutamide 160mg/d orally.Outcome measurements and statistical analysis The primary endpoint was radiographic progression-free survival. Secondary endpoints were overall survival, prostate-specific antigen (PSA) response, and time-to-PSA progression. Safety data were also assessed. Kaplan-Meier methods were used to descriptively analyse time-to-event endpoints.Results and limitations Overall, 214 patients received enzalutamide treatment, 145 of whom were chemotherapy-naïve. Median radiographic progression-free survival was 8.1 mo (95% confidence interval: 6.1-8.3); median overall survival had not been reached. Unconfirmed PSA response rate was 27% (48 of 181). Median time-to-PSA progression was 5.7 mo (95% confidence interval: 5.6-5.8). The most common treatment-emergent adverse events were fatigue (32%), decreased appetite (25%), asthenia (18%), back pain (17%), and arthralgia (16%). No seizures were reported.Conclusions Enzalutamide showed antitumour activity in some patients with mCRPC who had previously progressed following ≥24 wk of abiraterone acetate plus prednisone treatment.Patient summary Patients with mCRPC who progressed on previous abiraterone acetate plus prednisone treatment, with or without prior chemotherapy, received enzalutamide. Although cross-resistance between the two agents was observed in a majority of patients, some still benefited from enzalutamide treatment.
Version of record
Antineoplastic Combined Chemotherapy Protocols
Drug Resistance, Neoplasm
Prostatic Neoplasms, Castration-Resistant
Prostate Cancer Targeted Therapy Group
License start date
European urology, 2018, 74 (1), pp. 37 - 45