Pre-existing CVD linked to increased mortality with abiraterone, enzalutamide
medwireNews: Elderly patients with prostate cancer and pre-existing cardiovascular disease (CVD) have a significantly higher short-term mortality risk following abiraterone acetate or enzalutamide treatment than those without CVD, US study findings indicate.
Grace Lu-Yao (Sidney Kimmel Medical College, Philadelphia, Pennsylvania) and co-investigators therefore recommend that “a multidisciplinary team, including a cardiologist, evaluate patients having pre-existing CVDs in the process of making treatment decisions and monitoring potential side effects.”
The study, published in European Urology, expands on earlier research by Lu-Yao and team which showed an increased short-term mortality risk among abiraterone acetate treated patients with CVD. Those findings, reported by medwireNews, did not, however, include data for patients receiving enzalutamide.
In the current study, approximately two-thirds of the 3876 men aged 65 years or older with prostate cancer who were identified from linked SEER and Medicare databases had pre-existing CVD before abiraterone or enzalutamide initiation. CVD was defined as acute myocardial infarction, atrial fibrillation, congestive heart failure stroke, or ischemic heart disease.
At 6 months post-treatment, mortality rates ranged from 24% to 34% among the subgroup of patients with CVD who had received abiraterone and prior chemotherapy and from 23% to 37% among those who had received enzalutamide and prior chemotherapy, depending on the type of CVD present. For patients with no CVD the rates were 22% and 28%, respectively, and a similar pattern was observed for the patients who had not received prior chemotherapy.
The researchers note that mortality rates were higher “than those reported by the pivotal trials” for both drugs and thus “highlight the importance of conducting outcome evaluation among patients not meeting pivotal trial eligibility criteria in the real-world setting.”
Compared with patients who had no history of CVD, those with three or more CVD diagnoses had a 43% increased risk for death in the 6 months following abiraterone acetate or enzalutamide treatment if they had also received docetaxel chemotherapy and 56% higher risk if they had not received chemotherapy.
Those with one or two CVDs were only at significantly increased risk for death during the first 6 months if they had not received chemotherapy (relative risk=1.16).
In line with their previous findings, Lu-Yao and co-investigators also observed that abiraterone treatment without chemotherapy was associated with significant 34–55% increases in hospitalization rates post-treatment relative to pretreatment across all CVD categories including those with no CVD. Conversely, there was no such risk increase with enzalutamide.
Lu-Yao et al conclude that their study raises “important questions regarding the potential toxicity of [abiraterone acetate] or [enzalutamide] in ‘real-world’ patients, and should spur clinicians to integrate this knowledge into their clinical decision making for patients with [prostate cancer] and CVD.”
By Laura Cowen
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