Association of Biomarkers with Serious Cardiac Adverse Events during Abiraterone Acetate Treatment in Castration Resistant Prostate Cancer

BACKGROUND Abiraterone acetate is an effective drug for castration-resistant prostate cancer, but cardiac serious adverse events (SAEs) may occur. We studied their association with N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin T (TnT) during abiraterone therapy. PATIENTS AND METHODS In a single institution, 17 patients were treated with abiraterone acetate 1 g daily with concomitant prednisone and then switched to dexametasone plus canrenone. Blood samples for PSA, NT-proBNP, and TnT were obtained at baseline and after 1, 3, and 6 months. RESULTS Five patients (29.4%) experienced G3 to 4 cardiac SAEs after a median of 13 weeks (range, 9-32), including pulmonary edema, heart failure, acute coronary syndrome, sinus bradycardia with syncope, and pulmonary edema. At baseline, 4 weeks, and 3 months, median NT-proBNP and TnT levels were higher in patients with subsequent cardiac SAEs (P= .03 and P= .04 for NT-proBNP and TnT at 3 months, respectively). After switching to dexametasone and introducing canrenone, no additional cardiac SAEs were noted. Overall response rate was 67%. CONCLUSIONS Our study suggests a higher than expected risk of cardiac SAEs during abiraterone treatment which may well be due to the small sample size and the unrestricted entry criteria. However, baseline and frequent NT-proBNP and TnT monitoring predicted a higher risk for cardiac SAE. Larger studies should confirm our findings.