Journal of Oncology Pharmacy Practice | 2021
Abiraterone acetate-associated QT prolongation and torsades de pointes: Postmarketing cases reported to FDA
Abstract
Abiraterone acetate is a standard treatment option used in combination with androgen deprivation therapy (ADT) for metastatic prostate cancer. Abiraterone is an androgen biosynthesis inhibitor associated with cardiovascular adverse reactions due to mineralocorticoid excess and hypokalemia. The Division of Pharmacovigilance at the U.S. Food and Drug Administration (FDA) analyzed postmarketing reports of QT prolongation and/or Torsades de Pointes (TdP) associated with abiraterone. We herein report our findings of QT prolongation and TdP with abiraterone as a clinical consequence of hypokalemia and the regulatory action taken by the FDA. We searched the FDA Adverse Event Reporting System (FAERS) and the literature for all cases of QT prolongation or TdP reported with abiraterone submitted from the date of U.S. approval (April 28, 2011) through May 1, 2019. Table 1 shows the characteristics of the case series. We identified nine cases of QT prolongation among patients taking abiraterone, including five cases that developed TdP. In one TdP case, the patient experienced fatal cardiac arrest six days after an episode of TdP with severe hypokalemia. We observed hypokalemia in six cases, including four