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Apalutamide vs Abiraterone for Deep PSA Response Among Patients With Castration-Sensitive Prostate Cancer
In a real-world analysis of patients with metastatic castration-sensitive prostate cancer, a higher rate of patients treated with apalutamide achieved a deep prostate-specific antigen (PSA) response than patients treated with abiraterone acetate.
Data on patients with metastatic castration-sensitive prostate cancers from 77 community urology practices in the United States were included. Patients were classified based on first filled prescription for apalutamide (n = 364) or abiraterone acetate (n = 147), beginning September 17, 2019, and were followed until the earliest of treatment discontinuation, treatment switch, end of clinical activity, or end of data availability, on September 17, 2021. Deep PSA response was defined as the earliest attainment of ≥90% reduction of PSA relative to baseline.
At 6 months after the first filled prescription, patients initiated on apalutamide were 53% more likely to achieve a 90% reduction in PSA than those on abiraterone acetate (P = .016). There were similar results observed by 9- and 12-months post-index. In the apalutamide cohort, the median time to a 90% reduction in PSA was 3.5 months, and the median time was not reached for the abiraterone acetate cohort.
Study authors concluded, “significantly more patients achieved [≥90% reduction of PSA] with apalutamide vs abiraterone acetate” and “apalutamide was associated with faster time to [90% reduction of PSA] than abiraterone acetate.” They went on to clarify that these “findings are important given the association between [deep PSA response] and survival” in metastatic castration-sensitive prostate cancer.”
Source:
Lowentritt B, Pilon D, Waters D, et al. Comparison of prostate-specific antigen response in patients with metastatic castration-sensitive prostate cancer initiated on apalutamide or abiraterone acetate: A retrospective cohort study. Urol Oncol. 41(5):252e19-252e27. doi:10.1016/j.urolonc.2023.03.013
