Risk of metabolic and cardiovascular adverse events with abiraterone or enzalutamide among men with advanced prostate cancer

When You Get to the Fork in the Road, Take It: The Challenges in Managing Patients With Advanced Prostate Cancer

As is the case with most solid tumors, the heterogeneity of the disease biology of prostate cancer presents clinicians managing this disease with daily challenges. However, in contrast to other common cancers such as breast, lung, and colorectal cancers, there are unique challenges in prostate cancer management, including the variety of clinicians who manage aspects of the disease (urologists, medical oncologist, radiation oncologists) and the striking absence of prospective comparative data to inform the optimal sequence of systemic therapy in patients with metastatic castration-resistant disease. The purpose of this review is to attempt to assist practicing oncologists with sorting through the myriad of prostate cancer disease subsets and the challenges in making therapeutic decisions in multiple data-free zones given the absence of level 1 comparative clinical trials in the metastatic hormone-sensitive and castration-resistant states.

Assessment of Cardiovascular Events Caused by New-Generation Androgen Receptor Pathway Inhibitors Used for Prostate Cancer: A Real-World Study in Japan

INTRODUCTION

Androgen receptor pathway inhibitors (ARPIs) that significantly improve the prognosis of patients with prostate cancer include abiraterone acetate (androgen synthesis inhibitor) and enzalutamide (androgen receptor inhibitor). A recent analysis of ARPI and cardiovascular events using the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) has been reported; however, the evidence on cardiovascular events for abiraterone acetate and enzalutamide in real-world clinical practice is insufficient. Using a large Japanese database of medical institutions, the Japanese Medical Data Center (JMDC) medical institution database (JMDC Inc., Tokyo, Japan), this study tested the hypothesis that the risk of cardiovascular events with enzalutamide is lower than that with abiraterone acetate.

METHOD

Using the JMDC medical institution database, patients with new use of abiraterone acetate or enzalutamide who had not experienced a major cardiovascular event between October 2014 and February 2022 were included. After adjusting for age, comorbidities, and concomitant medications using propensity score matching, cumulative incidence rates were compared for cardiovascular death and all cardiovascular events as the primary endpoints, and major cardiovascular events, myocardial infarction, heart failure, and stroke as secondary endpoints.

RESULT

A total of 3,033 patients in the enzalutamide group and 2,021 in the abiraterone group met the eligibility criteria. After propensity score matching, the cohort included 1,940 patients in the enzalutamide group and 1,940 patients in the abiraterone group. Enzalutamide was associated with significantly lower cumulative rates of cardiovascular death (hazard ratio [HR]: 0.30, 95% confidence interval [CI]: 0.10-0.93), all cardiovascular events (HR: 0.79, 95% CI: 0.64-0.98), major cardiovascular events (HR: 0.79, 95% CI: 0.64-0.97), and myocardial infarction (HR: 0.62, 95% CI: 0.46-0.84) compared to abiraterone.

CONCLUSION

In a national sample of males with prostate cancer, those newly treated with enzalutamide had a lower risk of adverse cardiovascular events than those treated with abiraterone acetate.

Adverse events in men with advanced prostate cancer treated with androgen biosynthesis inhibitors and androgen receptor inhibitors

BACKGROUND

The use of androgen biosynthesis and second-generation androgen receptor inhibitors for advanced prostate cancer is increasing. Because these therapies alter the androgen pathway, they have been associated with cardiometabolic and neurocognitive toxicities. Although their safety profiles have been assessed in clinical trials, real-world data are limited.

METHODS

A 20% sample of national Medicare claims was used to perform a retrospective cohort study of Medicare beneficiaries with advanced prostate cancer treated with androgen biosynthesis (ie, abiraterone) and second-generation androgen receptor inhibitors between 2012 and 2019. Outcomes were assessed after the first fill of either class of drug for the 12-month period after starting therapy. The primary outcome was a hospital admission or emergency department visit for a cardiometabolic event. Secondary outcomes included neurocognitive events and fractures. Multivariable regression was used to assess the association between the class of drug and occurrence of an adverse event.

RESULTS

There were 3488 (60%) men started on an androgen biosynthesis inhibitor and 2361 (40%) started on an androgen receptor inhibitor for the first time. Cardiometabolic adverse events were more common in men managed with androgen biosynthesis inhibitor (9.2% vs 7.5%, P = .027). No difference between androgen biosynthesis and androgen receptor inhibitors was observed for neurocognitive events (3.3% vs 3.4%, respectively; P = .71) or fractures (4.2% vs 3.6%, respectively; P = .26).

CONCLUSIONS

Men with advanced prostate cancer initiating an androgen biosynthesis inhibitor for the first time more commonly had cardiometabolic events than those started on androgen receptor inhibitors. Neurocognitive events and fractures did not differ by drug class.

The 340B Program and oral specialty drugs for advanced prostate cancer

INTRODUCTION

Expensive oral specialty drugs for advanced prostate cancer can be associated with treatment disparities. The 340B program allows hospitals to purchase medications at discounts, generating savings that can improve care of the socioeconomically disadvantaged. This study assessed the effect of hospital 340B participation on advanced prostate cancer.

METHODS

The authors performed a retrospective cohort study of Medicare beneficiaries with advanced prostate cancer from 2012 to 2019. The primary outcome was use of an oral specialty drug. Secondary outcomes included monthly out-of-pocket costs and treatment adherence. We evaluated the effects of 1) hospital 340B participation, 2) a regional measure vulnerability, the social vulnerability index (SVI), and 3) the interaction between hospital 340B participation and SVI on outcomes.

RESULTS

There were 2237 and 1100 men who received care at 340B and non-340B hospitals. There was no difference in specialty drug use between 340B and non-340B hospitals, whereas specialty drug use decreased with increased SVI (odds ratio, 0.95, p = .038). However, the interaction between hospital 340B participation and SVI on specialty drug use was not significant. Neither 340B participation, SVI, or their interaction were associated with out-of-pocket costs. Although hospital 340B participation and SVI were not associated with treatment adherence, their interaction was significant (p = .020). This demonstrated that 340B was associated with better adherence among socially vulnerable men.

CONCLUSIONS

The 340B program was not associated with specialty drug use in men with advanced prostate cancer. However, among those who were started on therapy, 340B was associated with increased treatment adherence in more socially vulnerable men.

Cardiovascular Toxicity Associated With Androgen Receptor Axis-Targeted Agents in Patients With Prostate Cancer: A Meta-analysis of Randomized Controlled Trials

INTRODUCTION

Second-generation androgen receptor axis-targeting (ARAT) agents have become a standard treatment for patients with advanced prostate cancer (PC), however much remains unknown about the potential cardiovascular toxicities.

PATIENTS AND METHODS

We performed a systematic search of PubMed, Embase, Web of Science, and Cochrane library for randomized controlled trials of patients receiving ARAT agents for PC from inception to March 2023. The odds ratios (ORs) of all-grade and high-grade cardiovascular adverse events (CVAEs) for patients treated with and without ARAT agents were pooled for meta-analysis. Subgroup analyses based on PC type and treatment regimen were conducted.

RESULTS

A total of 15 double-blind placebo-controlled phase 3 trials comprising 15,842 patients were included. In addition to hot flush and hypertension of any degree of severity, inclusion of ARAT agents was associated with a significantly higher risk of acute myocardial infarction (OR: 1.96, 95% CI: 1.05-3.68, P = .04), myocardial infarction (OR: 2.44, 95% CI: 1.27-4.66, P = .007) and angina pectoris (OR: 2.00, 95% CI: 1.00-4.02, P = .05). With regard to individual ARAT agents, enzalutamide was associated with a significantly higher risk of acute myocardial infarction (OR: 3.11, 95% CI: 1.17-8.28, P = .02), coronary artery disease (OR: 8.33, 95% CI: 1.54-44.95, P = .01), and high-grade hypertension (OR: 4.94, 95% CI: 1.11-22.06, P = .04), while abiraterone and apalutamide were associated with a significantly higher risk of angina pectoris (OR: 5.48, 95% CI: 1.23-24.33, P = .03) and myocardial infarction (OR: 7.00, 95% CI: 1.60-30.62, P = .01), respectively.

CONCLUSION

The inclusion of ARAT agents was associated with a significantly higher risk of several CVAEs. Clinicians should remain vigilant, both in pre-treatment screening and monitoring for clinical symptoms and signs, when considering ARAT agent particularly for patients with pre-existing risk factors.

Research Protocol for an Observational Health Data Analysis on the Adverse Events of Systemic Treatment in Patients with Metastatic Hormone-sensitive Prostate Cancer: Big Data Analytics Using the PIONEER Platform

Combination therapies in metastatic hormone-sensitive prostate cancer (mHSPC), which include the addition of an androgen receptor signaling inhibitor and/or docetaxel to androgen deprivation therapy, have been a game changer in the management of this disease stage. However, these therapies come with their fair share of toxicities and side effects. The goal of this observational study is to report drug-related adverse events (AEs), which are correlated with systemic combination therapies for mHSPC. Determining the optimal treatment option requires large cohorts to estimate the tolerability and AEs of these combination therapies in "real-life" patients with mHSPC, as provided in this study. We use a network of databases that includes population-based registries, electronic health records, and insurance claims, containing the overall target population and subgroups of patients defined by unique certain characteristics, demographics, and comorbidities, to compute the incidence of common AEs associated with systemic therapies in the setting of mHSPC. These data sources are standardised using the Observational Medical Outcomes Partnership Common Data Model. We perform the descriptive statistics as well as calculate the AE incidence rate separately for each treatment group, stratified by age groups and index year. The time until the first event is estimated using the Kaplan-Meier method within each age group. In the case of episodic events, the anticipated mean cumulative counts of events are calculated. Our study will allow clinicians to tailor optimal therapies for mHSPC patients, and they will serve as a basis for comparative method studies.

Abiraterone-Induced Secondary Hypertension: Two Wrongs Don't Make a Right

Abiraterone, an inhibitor of both 17α-hydroxylase and 17,20-lyase, is considered a novel, state-of-the-art, life-prolonging therapy in the urologists' arsenal when treating prostate cancer. Despite its efficacy, it is linked with an increased risk of cardiovascular adverse effects. Herein, we report a case in which the administration of abiraterone resulted in a full-blown syndrome of apparent mineralocorticoid excess despite the concomitant administration of prednisolone; that is, secondary hypertension, hypokalemia, metabolic alkalosis, as well as elevated levels of adrenocorticotropic hormone (ACTH).

Profiling of Skeletal Muscle and Adipose Tissue Depots in Men with Advanced Prostate Cancer Receiving Different Forms of Androgen Deprivation Therapy

Background

Androgen deprivation therapy (ADT) is a common treatment modality for men with prostate cancer. Increases in adipose tissue mass and decreases in skeletal muscle mass are known on-target adverse effects of standard ADT. The effects of newer agents such as abiraterone acetate (ABI) and enzalutamide (ENZA) on body composition and how these compare with standard luteinizing hormone-releasing hormone agonists (aLHRHs) are unclear.

Objective

To assess the effects of different forms of androgen deprivation therapy on body composition in men with prostate cancer.

Design setting and participants

Using a retrospective design, 229 patients receiving aLHRHs alone (n = 120) or in combination with ABI (n = 53) or ENZA (n = 56) were studied.

Outcome measurements and statistical analysis

Muscle, visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT) were assessed at baseline, 6 mo, and 18 mo after initiating therapy using a cross-sectional densitometry analysis performed on standard of care computed tomography images. Response trajectories for all treatment groups were calculated via a two-way analysis of variance post hoc test, for both within-group and between-group differences.

Results and limitations

Treatment with aLHRHs, ABI, and ENZA was associated with a median muscle volume loss of -1.4%, -4.8%, and -5.5% at 6 mo, and -7.1%, -8.1%, and -8.3% at 18 mo, respectively. Therapy with aLHRHs was associated with minimal changes in VAT (0.3% at 6 mo and -0.1% at 18 mo). ABI therapy was associated with significant increases in VAT at 6 mo (4.9%) but not at 18 mo (0.5%), and ENZA therapy was associated with significant decreases in VAT (-4.6% at 6 mo and -5.4% at 18 mo). With respect to SAT, treatment with aLHRHs was associated with increases over time (8.6% at 6 mo and 4.7% at 18 mo), ABI was associated with decreases over time (-3.6% at 6 mo and -6.8% at 18 mo), and ENZA had no clear effects (1.7% at 6 mo and 3.3% at 18 mo).

Conclusions

ADT regimens cause significant short-term losses in muscle mass, with the most rapid effects occurring with ABI and ENZA. The three regimens have disparate effects on SAT and VAT, suggesting distinct roles of androgens in these tissues.

Patient summary

Androgen deprivation therapy alters body composition in men with prostate cancer. Abiraterone and enzalutamide are associated with losses in muscle mass compared with luteinizing hormone-releasing hormone agonists. These treatments impact subcutaneous and visceral fat mass, suggesting distinct roles of androgens in these tissues.

Cardiovascular Adverse Events Associated With New-Generation Androgen Receptor Pathway Inhibitors (ARPI) for Prostate Cancer: A Disproportionality Analysis Based on the FDA Adverse Event Reporting System (FAERS)

BACKGROUND

The potential cardiovascular adverse events associated with new-generation androgen receptor pathway inhibitors (ARPI) in the treatment of prostate cancer remain unclear. We aimed to assess the pharmacovigilance (PV), reporting rate, severity, and reaction outcomes of major adverse cardiovascular events (MACE) related to new-generation ARPI for prostate cancer reported to the United States Food and Drug Administration Adverse Event Reporting System (FAERS).

METHODS

We analyzed reports of cardiovascular adverse events associated with drug therapy for prostate cancer submitted to FAERS between January 2014 and December 2022. Three primary new-generation ARPIs were identified: abiraterone acetate, enzalutamide, and apalutamide. Our primary composite endpoint was the PV of MACE caused by ARPIs in the treatment of prostate cancer, and the secondary endpoint was PV of other cardiovascular events. The software implemented was STATA 17.0 MP.

RESULTS

A total of 278,031 suspected drug-adverse event pairs related to drug treatment in patients with prostate cancer were identified, of which 10,861 reports were cardiovascular events, including 5800 reports of MACE and 5061 reports of other cardiovascular events. The majority of these cardiovascular adverse event reports came from the United States (36.6%) and were mostly older men (age 76.0 ± 8.6 years). Compared with enzalutamide, the constituent ratio of MACE caused by abiraterone acetate and apalutamide was significantly increased, but the incidence of severe MACE decreased significantly. The PV signal regarding MACE was detected in abiraterone acetate and apalutamide but not in enzalutamide.

CONCLUSION

Abiraterone acetate and apalutamide presumably are associated with a higher risk of MACE than enzalutamide in new-generation ARPI for prostate cancer. More extensive prospective studies and more extended follow-up periods need to confirm this further.

Real-world survival outcome comparing abiraterone acetate plus prednisone and enzalutamide for nonmetastatic castration-resistant prostate cancer

BACKGROUND

There is little evidence of abiraterone acetate (AA) plus prednisone for patients with non-metastatic castration-resistant prostate cancer (nmCRPC). In this study, we conducted a comparative analysis of real-world survival outcomes between AA plus prednisone and enzalutamide (Enz) in patients with nmCRPC, utilizing our consortium dataset.

MATERIALS AND METHODS

The clinical records of 133 nmCRPC patients treated with first-line Enz or AA plus prednisone were analyzed. The primary endpoints of the study were overall survival (OS) and cancer-specific survival (CSS). Cumulative incidence function (CIF) using Fine and Gray models was also utilized to assess non-cancer-caused death considering the competing risk of cancer-caused death.

RESULTS

During a median follow-up of 36 months, 34 patients (25.6%) had deceased, with a median OS of 99 months in the entire cohort. There were no significant differences in comorbidities between the Enz and AA groups. Time to PSA progression (TTPP: HR 0.81, 95% CI 0.51-1.30, P = 0.375) and CSS (HR 1.32, 95% CI 0.55-3.44, P = 0.5141) were comparable between the two groups. However, intriguingly, there was a trend towards shorter OS in patients treated with AA plus prednisone compared to Enz (HR 0.57, 95% CI 0.29-1.12, P = 0.0978, median of 99 and 69 months in Enz and AA groups, respectively). CIF analysis revealed that nmCRPC patients treated with AA plus prednisone were more likely to result in non-cancer-caused death than those treated with Enz (HR 5.22, 95% CI 1.88-14.50, P = 0.0014).

CONCLUSIONS

Our real-world survival analysis suggests that while AA plus prednisone may demonstrate comparable treatment efficacy to Enz in the context of nmCRPC, there may be an increased risk of non-cancer-caused death. Physicians should take into consideration this information when making treatment decisions for patients with nmCRPC.

Mental health care utilization among men with castration-resistant prostate cancer receiving abiraterone or enzalutamide

BACKGROUND

Abiraterone and enzalutamide are castration-resistant prostate cancer (CRPC) therapies with potentially distinct associations with mental health symptoms given their differing antiandrogen targets.

METHODS

We used national Veterans Health Administration data to identify patients with CRPC who received first-line abiraterone or enzalutamide from 2010 to 2017. Using Poisson regression, we compared outpatient mental health encounters per 100 patient-months on drug between the abiraterone and enzalutamide cohorts adjusting for patient factors (e.g., age). We compared mental health encounters in the year before versus after starting therapy using the McNemar test.

RESULTS

We identified 2902 CRPC patients who received abiraterone (n = 1992) or enzalutamide (n = 910). We found no difference in outpatient mental health encounters between the two groups (adjusted incident rate ratio [aIRR] 1.04, 95% confidence interval [CI] 0.95-1.15). However, men with preexisting mental health diagnoses received 81.3% of the outpatient mental health encounters and had higher rates of these encounters with enzalutamide (aIRR 1.21, 95% CI 1.09-1.34). Among patients with ≥1 year of enrollment before and after starting abiraterone (n = 1139) or enzalutamide (n = 446), there was no difference in mental health care utilization before versus after starting treatment (17.0% of patients vs. 17.6%, p = 0.60, abiraterone; 16.4% vs. 18.4%, p = 0.26, enzalutamide).

CONCLUSION

We found no overall differences in mental health care utilization between CRPC patients who received first-line abiraterone versus enzalutamide. However, men with preexisting mental health diagnoses received the majority of mental health care and had more mental health visits with enzalutamide.

In-office dispensing of oral targeted agents by urology practices in men with advanced prostate cancer

BACKGROUND

Management of men with advanced prostate cancer has evolved to include urologists, made possible by oral targeted agents (eg, abiraterone or enzalutamide) that can be dispensed directly to patients in the office. We sought to investigate whether this increasingly common model improves access to these agents, especially for Black men who are historically undertreated.

METHODS

We used 20% national Medicare data to perform a retrospective cohort study of men with advanced prostate cancer from 2011 through 2019, managed by urology practices with and without in-office dispensing. Using a difference-in-difference framework, generalized estimating equations were used to measure the effect of in-office dispensing on prescriptions for abiraterone and/or enzalutamide, adjusting for differences between patients, including race.

RESULTS

New prescription fills for oral targeted agents increased after the adoption of in-office dispensing (+4.4%, 95% confidence interval [CI] = 3.4% to 5.4%) relative to that for men managed by practices without dispensing (+2.4%, 95% CI = 1.4% to 3.4%). The increase in the postintervention period (difference-in-difference estimate) was 2% higher (95% CI = 0.6% to 3.4%) for men managed by practices adopting dispensing relative to men managed by practices without dispensing. The effect was strongest for practices adopting dispensing in 2015 (difference-in-difference estimate: +4.2%, 95% CI = 2.3% to 6.2%). The effect of dispensing adoption did not differ by race.

CONCLUSION

Adoption of in-office dispensing by urology practices increased prescription fills for oral targeted agents in men with advanced prostate cancer. This model of delivery may improve access to this important class of medications.

Second generation androgen receptor antagonists and challenges in prostate cancer treatment

Prostate cancer is a hormone-dependent malignancy, whose onset and progression are closely related to the activity of the androgen receptor (AR) signaling pathway. Due to this critical role of AR signaling in driving prostate cancer, therapy targeting the AR pathway has been the mainstay strategy for metastatic prostate cancer treatment. The utility of these agents has expanded with the emergence of second-generation AR antagonists, which began with the approval of enzalutamide in 2012 by the United States Food and Drug Administration (FDA). Together with apalutamide and darolutamide, which were approved in 2018 and 2019, respectively, these agents have improved the survival of patients with prostate cancer, with applications for both androgen-dependent and castration-resistant disease. While patients receiving these drugs receive a benefit in the form of prolonged survival, they are not cured and ultimately progress to lethal neuroendocrine prostate cancer (NEPC). Here we summarize the current state of AR antagonist development and highlight the emerging challenges of their clinical application and the potential resistance mechanisms, which might be addressed by combination therapies or the development of novel AR-targeted therapies.