Medication patterns of abiraterone acetate plus prednisone or enzalutamide and PSA progression in veterans with metastatic castration-resistant prostate cancer

Functional impact of androgen‐targeted therapy on patients with castration‐resistant prostate cancer

Context

Second‐generation androgen receptor inhibitors (ARIs) extend metastasis‐free survival, prolong overall survival, and delay symptoms when added to androgen deprivation therapy for the treatment of castration‐sensitive or castration‐resistant prostate cancer (CRPC). However, ARIs may adversely impact physical and cognitive function, thereby decreasing quality of life and prognosis.

Objective

To evaluate the evidence regarding the potential effects of ARIs on physical and cognitive function and to contextualize how drug‐related adverse effects may influence treatment decisions in CRPC.

Evidence acquisition

We performed a literature search using MEDLINE from January 1998 to June 2020 using terms relating to prostate cancer, androgen deprivation, and physical and cognitive function. We selected 61 publications for analysis.

Evidence synthesis

Treatment‐induced deterioration in physical and cognitive function may impair the independence and well‐being of patients with CRPC. Patient‐reported outcomes from clinical trials of ARIs provide quantitative evidence of their impact on these domains, which appears to vary between ARIs, reflecting the different adverse event profiles of these agents. Thus, the risk of physical or cognitive dysfunction may be managed or mitigated by appropriate selection of treatment options. Studies in patients with CRPC have assessed the cognitive effects of ARIs with validated instruments, whereas quantitative analysis of the impact on physical function has been limited.

Conclusion

Several validated instruments utilized for the assessment of physical and cognitive function in clinical studies have been adapted for clinical practice; however, consensus on the standardization of these assessments is required. Future clinical studies employing validated tools may generate data on the impact of ARIs and guide treatment decisions for patients with CRPC.

Patient summary

We review the hormonal therapies used to treat men with prostate cancer and the effects they have on physical and cognitive function. We discuss how to measure these effects and how this may assist when choosing treatment.

Outcomes Following Abiraterone versus Enzalutamide for Prostate Cancer: A Scoping Review

Abiraterone acetate (AA) and enzalutamide (ENZ) are commonly used for metastatic prostate cancer. It is unclear how their outcomes and toxicities vary with patient-specific factors because clinical trials typically exclude patients with significant comorbidities. This study aims to fill this knowledge gap and facilitate informed treatment decision making. A registered protocol utilizing PRISMA scoping review methodology was utilized to identify real-world studies. Of 433 non-duplicated publications, 23 were selected by three independent reviewers. ENZ offered a faster and more frequent biochemical response (30-50% vs. 70-75%), slowed progression (HR 0.66; 95% CI 0.50-0.88), and improved overall survival versus AA. ENZ was associated with more fatigue and neurological adverse effects. Conversely, AA increased risk of cardiovascular- (HR 1.82; 95% CI 1.09-3.05) and heart failure-related (HR 2.88; 95% CI 1.09-7.63) hospitalizations. Ultimately, AA was associated with increased length of hospital stay, emergency department visits, and hospitalizations (HR 1.26; 95% CI 1.04-1.53). Accordingly, total costs were higher for AA, although pharmacy costs alone were higher for ENZ. Existing data suggest that AA and ENZ have important differences in outcomes including toxicities, response, disease progression, and survival. Additionally, adherence, healthcare utilization, and costs differ. Further investigation is warranted to inform treatment decisions which optimize patient outcomes.

Prognostic impact of dose reduction in androgen receptor pathway inhibitors for castration-resistant prostate cancer

Background

Androgen receptor pathway inhibitors (ARPIs) such as abiraterone and enzalutamide have been shown to prolong survival in patients with advanced prostate cancer. However, there is limited evidence on the anticancer effect of a reduced dose of ARPIs. This study compared the prognosis in patients with chemotherapy-naïve castration-resistant prostate cancer (CRPC) between ARPI treatment with standard dose and treatment with reduced dose.

Methods

Japanese patients who were treated with ARPI as first-line treatment for CRPC between 2014 and 2018 were included. The associations between dose reduction and clinicopathological factors, progression-free survival, and overall survival were investigated.

Results

Of the 162 patients included, 33 (20.4%) patients had their dose reduced during ARPI treatment. In the multivariate analysis, higher PSA, abiraterone treatment, and dose reduction were significant prognostic factors for progression-free survival (PFS); however, dose reduction was not associated with overall survival. In the enzalutamide-treated group, the median PFS was 12.1 months (95% CI, 8.5–21.4 months) in the standard-dose group and 7.2 months (95% CI, 5.0–11.5 months) in the reduced-dose group (P = 0.038).

Conclusion

This study suggests inferior oncological outcome when treated with reduced-dose ARPI for CRPC. Full-dose administration of ARPI for CRPC may be appropriate if feasible.