Efficacy of degarelix in prostate cancer patients following failure on luteinizing hormone-releasing hormone agonist treatment: results from an open-label, multicentre, uncontrolled, phase II trial (CS27)

Effectiveness of GnRH Antagonists and Agonists in Patients with Hormone-Sensitive Prostate Cancer: A Retrospective Study

Objective

To assess the effectiveness of gonadotropin-releasing hormone (GnRH) antagonists and agonists in the treatment of patients with hormone-sensitive prostate cancer (HSPC), thus providing valid data support for their clinical treatment.

Methods

We collected 52 and 65 HSPC patients treated with GnRH antagonists and agonists, respectively, in Tongji Hospital, Tongji Medical College of HUST between May 2019 and April 2021. Prostate-specific antigen (PSA) levels before and after treatment were recorded and analyzed. Further, univariate and multivariate logistic regressions were used to analyze the influencing factors of PSA control rate in HSPC patients.

Results

In patients receiving antagonist, the control rate of prostate-specific antigen (PSA) was 54.28% and 88% without and with abiraterone, respectively, and 47.91% and 72% in patients treated using agonist without and with abiraterone. In 32 pairs of patients obtained via propensity score matching, the PSA control rates were 84.38% and 53.13% for those receiving antagonists and agonists, respectively, and 66.67% and 50% for those without abiraterone, respectively. In addition, univariate logistic regression analysis showed that the type of androgen deprivation therapy (ADT) drugs and combined use of abiraterone had a significant effect on the control rate of PSA. Further multivariate logistic regression revealed that GnRH antagonists in ADT drugs were risk factors for PSA control rate.

Conclusion

The PSA control rate of HSPC patients treated with GnRH antagonist is significantly higher than that of the agonist group, and the use of GnRH antagonist is an independent predictor of PSA control rate.

Absence of PSA Flare With Apalutamide Administered 1 Hour in Advance With GnRH Agonists: Case Report

Objective

To examine the effects of apalutamide on endocrine function and flare prevention in metastatic hormone-sensitive prostate cancer (mHSPC) patients administered GnRH agonists.

Methods

The first newly diagnosed mHSPC patient took apalutamide for 2 weeks followed by combination with GnRH agonist, as recommended by clinical guidelines. Serum luteinizing hormone (LH), testosterone, and PSA were detected during the oral administration of apalutamide before and after ADT. Eight newly diagnosed mHSPC patients innovatively took apalutamide 1 hour before GnRH agonist administration; LH, testosterone and PSA were detected before and after ADT.

Results

In the first patient, LH and testosterone levels were increased during apalutamide monotherapy, and serum PSA levels decreased rapidly, demonstrating apalutamide effectively blocked AR signaling. In patients on the 1-hour regimen, combined treatment with apalutamide and GnRH agonists led to peak level of testosterone on day 3 and castration level on day 28, while PSA decreased continuously. No one experienced dysuria or bone pain worsen after ADT.

Conclusion

Taking apalutamide 1 hour in advance may effectively prevent the flare-up effect in prostate cancer patients treated with GnRH agonists. Compared with the 2-week regimen, the 1-hour regimen could simplify the treatment process and bring testosterone to castration levels in advance.

Progress in Clinical Research on Gonadotropin-Releasing Hormone Receptor Antagonists for the Treatment of Prostate Cancer

Gonadotropin-releasing hormone (GnRH) receptor agonists are still the most commonly used androgen deprivation treatment (ADT) drugs for prostate cancer in clinical practice. Currently, the GnRH receptor antagonists used for endocrine therapy for prostate cancer primarily include degarelix and relugolix (TAK-385). The former is administered by subcutaneous injection, while the latter is an oral drug. Compared to GnRH agonists, GnRH antagonists reduce serum testosterone levels more rapidly without an initial testosterone surge or subsequent microsurges. This review focuses on the mechanism of action of GnRH antagonists and agonists, the developmental history of GnRH antagonists, and emerging data from clinical studies of the two antagonists used as endocrine therapy for prostate cancer.

Cardiovascular risk profiles of GnRH agonists and antagonists: real-world analysis from UK general practice

PURPOSE

Androgen deprivation therapy (ADT) is the mainstay for the management of metastatic prostate cancer. Available pharmaceutical ADTs include gonadotropin-releasing hormone (GnRH) agonists and antagonists. Here, real-world data are presented from the UK general practitioner Optimum Patient Care Research Database. The study investigated the hypothesis that GnRH antagonists have lower cardiac event rates than GnRH agonists.

METHODS

The incidence of cardiac events following initiation of GnRH antagonist or agonist therapy was investigated in a population-based cohort study conducted in UK primary care between 2010 and 2017.

RESULTS

Analysis of real-world data from the UK primary care setting showed that relative risk of experiencing cardiac events was significantly lower with degarelix, a GnRH antagonist, compared with GnRH agonists (risk ratio: 0.39 [95% confidence interval 0.191, 0.799]; p = 0.01). Patients that received degarelix as first-line treatment switched treatment more frequently (33.7%), often to a GnRH agonist, than those who initiated treatment with a GnRH agonist (6.7-18.6%).

CONCLUSION

Screening for known or underlying vascular disease and identifying those at high risk of a cardiac event is important for risk mitigation in patients with prostate cancer receiving hormone therapy. The GnRH antagonist degarelix conferred a significantly lower risk of cardiac events than GnRH agonists. Prior to treatment, patients should be stratified based on level of cardiovascular (CV) risk, and appropriate lifestyle, and pharmacological interventions to mitigate CV risk should be recommended. CV risk factors and patient response to the intervention should be monitored at regular intervals.

Prescription switching: Rationales and risks

BACKGROUND

Therapeutic drug switching is commonplace across a broad range of indications and, within a drug class, is often facilitated by the availability of multiple drugs considered equivalent. Such treatment changes are often considered to improve outcomes via better efficacy or fewer side effects, or to be more cost-effective. Drug switching can be both appropriate and beneficial for several reasons; however, switching can also be associated with negative consequences.

AIM

To consider the impact of switching in two situations: the use of statins as a well-studied example of within-class drug switching, and gonadotropin-releasing hormone (GnRH)-targeting drug switching as an example of cross-class switching.

RESULTS

With the example of statins, within-class switching may be justified to reduce side effects, although the decision to switch is often also driven by the lower cost of generic formulations. With the example of GnRH agonists/antagonists, switching often occurs without the realisation that these drugs belong to different classes, with potential clinical implications.

CONCLUSION

Lessons emerging from these examples will help inform healthcare practitioners who may be considering switching drug prescriptions.

A Case of Switching from GnRH Agonist to Antagonist for Castration Resistant Prostate Cancer Control

GnRH antagonist and GnRH agonist are widely used as androgen deprivation therapy for metastatic prostate cancer. A previous report demonstrated that patients with PSA levels of >20 ng/mL using GnRH antagonists showed favorable outcomes in comparison to those using GnRH agonists. An 82-year old male patient with edema, a stony hard nodule on his prostate, and an initial PSA level of 6,717 ng/mL was referred to our hospital due to suspected prostate cancer. He received prostate needle biopsy and was diagnosed with prostate cancer with bone metastasis, with a Gleason Score of 4 + 4 = 8. He was then treated with a GnRH agonist (leuprorelin acetate) and bicalutamide from July 2015. Although his PSA level decreased to 582.0 ng/mL in December 2015, his PSA level gradually increased and CRPC developed. He indicated that he did not wish to take 2nd generation anti-androgen drugs or receive systemic chemotherapy. We introduced a GnRH antagonist (degarelix) in February 2015; his PSA level did not change and his CRPC was controlled. We herein report a case in which changing a GnRH agonist to a GnRH antagonist contributed to CRPC control.

Switching from a gonadotropin-releasing hormone (GnRH) agonist to a GnRH antagonist in prostate cancer patients: A systematic review and meta-analysis

INTRODUCTION

We sought to address whether there are clinical responses when patients who are failing gonadotropin-releasing hormone (GnRH) agonist therapy are switched to degarelix. Androgen-deprivation therapy remains the backbone of treatment for disseminated prostate cancer and may be achieved with orchiectomy, GnRH agonists, or degarelix, a GnRH antagonist.

METHODS

We conducted a systematic review and meta-analysis with a search of the BIOSIS Previews, Embase, International Pharmaceutical Abstracts, MEDLINE, and Google Scholar databases using key terms. Quantitative meta-analysis was performed to provide a pooled estimate of prostate specific antigen (PSA) response at three months.

RESULTS

Thirteen studies were identified, eight of which were included in the qualitative and quantitative analyses. Patient characteristics were broadly similar between the studies. Out of 155 patients across all included studies, 20 had stable PSA after the switch (12.9%), 14 had a 10-30% decrease in PSA (9.0%), three had a 30-50% decrease (1.9%), and 13 had a more than 50% decrease (8.4%). Random effects meta-analysis of these data demonstrated a pooled response rate of 27.75% (95% confidence interval 18.9-36.5%; I²=7.9%). Changes in testosterone levels following the switch could not be quantitatively assessed due to lack of sufficient data.

CONCLUSIONS

Our results suggest that a switch to GnRH antagonist following progression on a GnRH agonist may result in a stable or decreased PSA at three months in about 30% of patients. This information should be considered among the potential options to discuss with patients with a rising PSA on GnRH agonist therapy.

Degarelix versus luteinizing hormone-releasing hormone agonists for the treatment of prostate cancer

INTRODUCTION

Androgen deprivation therapy (ADT) is the mainstay for advanced, hormone-sensitive prostate cancer, and options include surgical castration, luteinizing hormone-releasing hormone (LHRH) agonist, and more recently, gonadotropin releasing hormone (GnRH) antagonist therapy. Our understanding of the mechanisms and adverse effects of ADT has increased substantially, including the class-specific adverse effects of ADT. Areas covered: This review will summarize the pharmacodynamic and pharmacokinetic properties of the GnRH antagonist degarelix and its role in the management of advanced prostate cancer, the clinical evidence supporting its regulatory approval, as well as potential benefits and disadvantages over traditional LHRH agonist therapy. Expert opinion: Degarelix represents a newer class of ADT that results in a rapid and reliable decline in serum testosterone, a quality that makes it particularly advantageous in men presenting with symptomatic, hormone-sensitive prostate cancer. Due to differences in mechanism of action, there is observational data suggesting a potential cardiovascular and even oncologic benefit over traditional LHRH agonist therapy. Further research is ongoing to more clearly define this potential benefit.