medwireNews: Men receiving enzalutamide for prostate cancer have a significantly lower risk for sepsis, pneumonia, and cellulitis or skin abscess than those treated with abiraterone, indicates a retrospective cohort study from Hong Kong.
There was no difference between the treatments with respect to the risk for urinary tract infections (UTIs), however, but the researchers point out that “in patients with metastatic prostate cancer, the risk of UTI is typically multifactorial.”
They continue: “For instance, given the advanced stage of [prostate cancer] in this cohort, the included patients are expected to have certain degrees of voiding dysfunction and bladder outlet obstruction, not to mention those requiring catheterization, all of which may alter the risk of UTI.”
The investigators explain that an earlier “pharmacovigilance analysis of adverse events found that infections accounted for 13% and 9% of fatal adverse events in patients receiving abiraterone and enzalutamide, respectively,” but head-to-head comparisons are lacking.
The team collated records from the Clinical Data Analysis and Reporting System, a population-based database, on 1582 men who received abiraterone plus prednisone (n=923) or enzalutamide (n=659) in combination with androgen deprivation therapy between December 1999 and March 2021.
Patients were aged a median of 71–73 years, and the abiraterone and enzalutamide groups were well balanced for clinical and treatment characteristics except for a lower prevalence of diabetes in the former, at 13.4% versus 26.0%.
Multivariable regression analysis, with mortality as a competing event, showed that enzalutamide-treated patients had a significantly lower cumulative incidence of sepsis, pneumonia, and cellulitis or skin abscess than those given abiraterone, with adjusted subhazard ratios (SHRs) of 0.70, 0.76, and 0.55, respectively.
The findings were similar when outcomes were analyzed as recurrent events, report Chi Fai Ng, from The Chinese University of Hong Kong, and colleagues in Cancer.
Although the risk for UTIs was comparable in the overall cohort, subgroup analysis revealed a significantly reduced risk with enzalutamide versus abiraterone among patients with diabetes, with an SHR of 0.48.
“One plausible explanation is that diabetes mellitus is a strong risk factor per se for UTI, and the use of prednisolone, a potent immunosuppressant, in these patients with diabetes mellitus may further increase the susceptibility to UTIs,” comment the researchers.
Discussing the results, Ng and co-authors say that “[t]he lower infection risk with enzalutamide compared to abiraterone with prednisone was likely driven by the avoidance of concomitant glucocorticoid use.”
They continue: “This mechanism would be expected to extend to other nonsteroidal antiandrogen agents like apalutamide and darolutamide, which also do not require concomitant steroid administration.”
And the team concludes: “The potential for a lower infection profile with nonsteroidal antiandrogen monotherapy in this setting is an important consideration for clinicians when selecting the optimal treatment approach.”
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Cancer 2024; doi:10.1002/cncr.35472
