Prostate cancer patients with cardiovascular disease (CVD) who are treated with abiraterone acetate (Zytiga) have an increased risk of death within 6 months of starting therapy, compared with those without preexisting CVD, according to an analysis of Surveillance, Epidemiology, and End Results (SEER)–Medicare linked data.
Of 2,845 patients diagnosed with prostate cancer between 1991 and 2013 and treated with abiraterone acetate (AA) between 2011 and 2014, 1,924 (67.6%) had at least one serious preexisting CVD condition. Mortality within 6 months of treatment initiation in those with preexisting CVD ranged from 21.4% to 25.6%, depending on the type of condition, compared with 15.8% among those with no preexisting CVD, Grace Lu-Yao, PhD, reported during a press conference highlighting data to be presented at the upcoming American Association for Cancer Research annual meeting in Atlanta.
An additional analysis of health care utilization showed that AA treatment was associated with risks for all patients, regardless of CVD; among patients without chemotherapy and without CVD, the hospitalization rate increased by 53%, and in those with preexisting CVD the rate increased from 34% to 55%, depending on the cardiovascular condition, said
Since patients with preexisting CVD are frequently excluded from clinical trials of AA, its effects in this population are uncertain. However, these data – though limited by the retrospective nature of the study – provide evidence that a significant proportion of patients treated in the real world differ from those in clinical trials, and therefore that the trial findings may not apply to patients who are excluded, said Dr. Lu-Yao, professor and vice chair in the department of medical Oncology at the Sidney Kimmel Medical College.
AA, which was initially approved in 2011 for use in combination with prednisone in patients with metastatic castration-resistant prostate cancer who were previously treated with docetaxel, received additional approval in 2018 for use in combination with prednisone for metastatic high-risk castration-sensitive prostate cancer.
The potential for expanded use of AA further underscores the need for improved understanding of its effects in the real-world setting, she noted.
This study was funded by a Pennsylvania CURE Program award and the National Cancer Institute. Dr. Lu-Yao has no direct conflicts to declare except that her spouse, who has no involvement with this study, is an officer of Sun Pharmaceutical Industries Inc.
SOURCE: Lu-Yao G et al. AACR 2019, .