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Conference Coverage

Real-World Cardiotoxicity of Abiraterone vs Enzalutamide for Prostate Cancer

February 16, 2021

Abiraterone is associated with greater risk of cardiovascular-related hospitalizations among men with prostate cancer than enzalutamide, according to a study presented at the virtual 2021 ASCO Genitourinary Cancer Symposium.

“Novel hormonal agents such as abiraterone and enzalutamide have demonstrated similar survival benefits against placebo groups in their respective clinical trials leading to their regulatory approval in both the pre- and post-chemotherapy settings in metastatic castration-resistant prostate cancer,” wrote Jason Hu, McGill University, Montreal, Quebec, Canada, and colleagues.

“Despite the overall tolerable risk profile, certain signals of cardiovascular toxicity were reported for these agents in clinical trials but little is known about their incidence in clinical practice,” they continued.

This retrospective study used public health care administrative databases to compare the cardiovascular safety of abiraterone and enzalutamide in patients with metastatic castration-resistant prostate cancer in the real-world setting.

Baseline characteristics, including pre-existing cardiovascular disease, were adjusted using inverse probability of treatment weighting (IPTW) with propensity score.

A total of 2183 patients were included in the cohort: 1,773 (81.2%) in the abiraterone group and 410 (18.8%) in the enzalutamide group. Prior to IPTW, mean age of patients in each group were 78 vs 76, respectively.

In the abiraterone group, 10.7% of patients had pre-existing arrythmia and 21.5% had diabetes. In the enzalutamide group, 15.1% had pre-existing arrythmia and 25.1% had diabetes. Crude incidence of cardiovascular-related hospitalizations were 10 events per 100 person-years for the abiraterone group vs 7 events per 100 person-years for the enzalutamide group.

After IPTW, abiraterone was associated with greater risk of cardiovascular-related hospitalization compared with enzalutamide (IPTW-hazard ratio (HR): 1.79, 95% confidence interval (95%CI): 1.04-3.09). In addition, risk of hospitalization for heart failure was greater in the abiraterone group (IPTW-HR: 3.02, 95%CI: 1.17-7.78).

“In our study population, there was a greater risk of cardiovascular-related hospitalizations for abiraterone users relative to enzalutamide users, in particular for hospitalization for heart failure,” concluded Hu and colleagues.

“Given the lack of evidence from randomized head-to-head comparisons of both agents, these results provide clinicians with additional insight on the cardiovascular risks of mCRPC patients treated with novel hormonal agents in the real-world and further large studies are required to corroborate these findings,” they added.—Janelle Bradley

Hu J, Aprikian AG, Vanhuyse M. Comparative cardiotoxicity of the novel hormonal agents abiraterone and enzalutamide in metastatic castration-resistant prostate cancer using real-world data. Presented at: the virtual 2021 ASCO Genitourinary Cancers Symposium; February 11-13, 2021. Abstract 62.

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