The study was published on researchsquare.com as a preprint and has not yet been peer reviewed.
Key Takeaways
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Men with metastatic castration-resistant prostate cancer (mCRPC) who began treatment on enzalutamide instead of abiraterone remained on treatment longer and lived a few more months.
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Older men and those with diabetes or cardiovascular disease also benefited more from enzalutamide.
Why This Matters
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The two oral androgen-receptor targeted agents haven’t gone head-to-head in a large, randomized trial and have been used somewhat interchangeably.
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Past studies have shown better outcomes with enzalutamide, but subgroup analyses did not include patients with cardiovascular disease or diabetes.
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The findings suggest that clinicians may consider preferentially initiating treatment with enzalutamide, particularly in older men and those with certain comorbidities.
Study Design
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The team compared outcomes in 5822 veterans who started treatment for mCRPC with abiraterone (57%) or enzalutamide (43%) between September 2014 and June 2017.
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The enzalutamide group was slightly older (mean age 75.8 vs 75.0) with a higher mean Charlson comorbidity index (4.4 vs 4.1) and higher rates of cardiovascular disease or diabetes (74.2% vs 70.6%).
Key Results
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Across the entire population, men receiving enzalutamide remained on treatment for longer (11.7 vs 9.1 months, P < .001) and demonstrated better overall survival (OS) (24.2 vs 22.1 months, P = .001).
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For men with cardiovascular disease or diabetes, median treatment duration (11.4 vs 8.6 months) and median OS (23.2 versus 20.5 months) were also significantly longer in the enzalutamide group.
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Similarly, men 75 years or older and those with Charlson comorbidity indices of at least 4 demonstrated a longer median treatment duration and overall survival on enzalutamide compared with abiraterone.
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In propensity score matching, enzalutamide was associated with decreased mortality (hazard ratio [HR], 0.90).
Limitations
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The study had a retrospective, observational design.
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Diagnoses and comorbidities were based on ICD-9 or ICD-10 codes.
Disclosures
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The study was funded by the Saint Louis Veterans Affairs Medical Center.
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The investigators reported no financial disclosures.
This is a summary of a preprint research study, “Survival of Veterans Treated with Enzalutamide and Abiraterone for Metastatic Castrate Resistant Prostate Cancer based on Comorbid Diseases,” led by Martin Schoen of the Saint Louis Veterans Affairs Medical Center. The study has not been peer reviewed. The full text can be found at researchsquare.com.
M. Alexander Otto is a physician assistant with a master’s degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who has worked for several major news outlets before joining Medscape and also an MIT Knight Science Journalism fellow. Email: [email protected].
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