Real-world Effectiveness and Treatment Adherence of Apalutamide in Non-metastatic Castration-resistant Prostate Cancer Patients.
Journal of Urology
INTRODUCTION AND OBJECTIVE:
Real-world evidence on apalutamide (APA), recently approved to treat patients with non-metastatic castration-resistant prostate cancer (nmCRPC), is limited in the United States (US). This study describes prostate-specific antigen (PSA) response and treatment adherence among patients with nmCRPC treated with APA, with stratification by Black and non-Black patients.
Electronic medical records of 63 US urology practices were obtained from PPS analytics and used to conduct this retrospective study of patients with nmCRPC who received APA on or after 02/14/2018 (index date). Included patients had ≥2 APA prescription fills and ≥12 months of prior prostate cancer management (baseline period). Patients were followed from the index date until a switch to another antineoplastic treatment, death, or end of data (10/04/2019). PSA response (≥50% decline from baseline PSA) and APA adherence rates measured by the medication possession ratio (total days of medication supplied relative to the time between the initiation and the end of the last prescription filled), were described for the overall population and also stratified by racial description, specifically Black and non-Black cohorts.
Overall, 193 patients with nmCRPC were initiated on APA (33 were Black [17%], 138 were non-Black [72%], and 22 had an unknown racial background [11%]). Most patients (76%) were aged between 71–90 years. The mean baseline PSA level for the overall, Black, and non-Black cohorts, was 7.0, 10.5, and 5.6 ng/mL, respectively (evaluated on 190, 33, and 135 patients). Among patients with ≥3 baseline PSA tests, median baseline PSA doubling time was 8.5, 7.3, and 8.4 months for the overall, Black, and non-Black cohorts, respectively (evaluated on 90, 16, and 70 patients). At 12 months follow-up, PSA response to APA was 86.0%, 93.1%, and 85.9% for the overall, Black, and non-Black cohorts among patients with both pre- and post-index PSA measurements, respectively (evaluated on 178, 29, and 128 patients). During a mean follow-up period of 11.0, 11.6, and 10.7 months, APA adherence was 93.6%, 90.1%, and 94.5% for the overall, Black and non-Black cohorts, respectively.
This real-world study of nmCRPC patients initiated on APA demonstrated good adherence to medication and robust PSA response consistent with the results from a prior published clinical trial.1 Moreover, these responses were observed in both Black and non-Black patients.
Lowentritt B, Brown G, Kernen K, Pilon D, Ellis L, et al. Real-world effectiveness and treatment adherence of apalutamide in non-metastatic castration-resistant prostate cancer patients. J Urol. 2021 Sep;206(suppl 3):e58.