Abstract A018: Abiraterone vs. enzalutamide: Does age impact one treatment over another

Abstract Background: Abiraterone and Enzalutamide are two of the most commonly used treatments for prostate cancer (PCa). Currently, both these medications are approved for similar clinical indications even though they have different toxicity profiles. This study aims to identify if patients and providers prefer one medication to another and if the choice depends on age. Methods: We used SEER-Medicare data to identify primary PCa patients diagnosed between 1999 and 2017. We excluded those diagnosed at death. Abiraterone and enzalutamide use was identified using part D files. Patients had 6 months continuous part D coverage prior to treatment. Age was parameterized categorically: 65-74 years, 75-84 years, and over 85 years. Descriptive statistics were generated and evaluated by Chi-square tests for all categorical variables. Multivariable logistic regression was used to investigate disparities between the treatments adjusting for demographic characteristics. Results: We identified 8,398 patients with PCa over 65 years of age; 4,180 used abiraterone and 4,218 used enzalutamide. The demographic characteristics for both groups were similar (p = 0.1557). Most patients were 65-74 years old (62.6% in the abiraterone group and 62.4% in the enzalutamide group), followed by approximately 30% of each group in the 75-84 age range. Finally, the enzalutamide group had 8.2% 85 years and older, while the abiraterone group had 7.1%. The appeared to be no preference in odds of use of either medication by age group. When comparing the very old (85+) to the 65-74 year olds (OR=0.906; 95% CI 0.745, 1.101; p=0.3727). Nor was there a statistical significance when comparing odds of use between 75-84-year-olds to those who were 65-74 (OR=0.978; 95%CI 0.873, 1.095; p=0.6927). Conclusion: Our study found that abiraterone and enzalutamide use among patients does not differ substantially by age groups. Further studies are warranted to understand these associations better. Citation Format: Nikita Nikita, Amy Shaver, Krupa Gandhi, Scott W. Keith, Swapnil Sharma, Grace Lu-Yao. Abiraterone vs. enzalutamide: Does age impact one treatment over another [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr A018.