Men with metastatic prostate cancer treated with abiraterone have a higher rate of hospitalization compared with those treated with enzalutamide, according to a recent study.
Further, in a novel finding, abiraterone treatment was associated with a higher risk for infection.
The study included one of the largest cohorts of patients treated with androgen receptor pathway inhibitors.
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“It is important to consider patient risks for adverse events when treating advanced prostate cancer,” said first author Forest Riekhof, a medical student at Saint Louis University School of Medicine in Saint Louis, Missouri. “This study reports increased rates of cardiovascular events and infections with abiraterone. Clinicians should consider the risk of these adverse events when deciding on treatment based on the underlying or comorbid conditions of each patient.”
The study, which was overseen by senior author Martin W. Schoen, MD, MPH, of the same institution, included 19,775 US veterans with metastatic prostate cancer, of whom 13,527 (68.4%) were treated with abiraterone and 6248 (31.6%) with enzalutamide. Among the abiraterone recipients, total hospitalizations increased from 465 per 1000 person-years in the year prior to treatment to 567 per 1000 person-years during treatment, the investigators reported in Clinical Genitourinary Cancer. In the enzalutamide group, total hospitalizations increased from 417 per 1000 person-years in the year prior to treatment to 430 per 1000 person-years during treatment.
The total hospitalization rate increased 22% for the abiraterone group compared with 3% for the enzalutamide arm in the 12 months after treatment initiation. Abiraterone therapy was associated with a greater increase in the rates of congestive heart failure, atrial fibrillation, urinary tract infections, sepsis, pneumonia, and acute kidney injury.
During the treatment period, hospitalizations for congestive heart failure increased by 65% in the abiraterone group compared with 23% among enzalutamide recipients. The atrial fibrillation rate increased by 67% in the abiraterone cohort compared with an 8.5% decrease in the enzalutamide cohort. Comparing the rate of infections during treatment with 1 year prior, the investigators observed a 44% increase in urinary tract infections, a 114% increase in sepsis, and a 93% increase in pneumonia with abiraterone vs enzalutamide, Riekhof and colleagues reported.
“It is well known that use of steroids, such as prednisone, can increase risk of infections,” Dr Schoen commented. “Because abiraterone requires prednisone, there may be an increased risk in the duration or severity of infections due to prednisone use. This new finding should be evaluated in additional studies.”
Further, acute kidney injury episodes increased by 4.6% in patients treated with abiraterone compared with a 21% decrease in patients treated with enzalutamide.
At treatment initiation, the enzalutamide-treated patients were significantly older (mean 75.8 vs 74.5 years) and had a significantly higher Charlson comorbidity index compared with the abiraterone group (mean 4.4 vs 4.0). The enzalutamide group received treatment significantly longer than the abiraterone group (median 9.0 vs 8.0 months).
Reference
Riekhof F, Yan Y, Bennett CL, et al. Hospitalizations among veterans treated for metastatic prostate cancer with abiraterone or enzalutamide. Clin Genitourin Cancer. Published online July 11, 2023. doi:10/.1016/j.clgc.2023.07.006
