Efficacy of treatment with a GnRH antagonist in prostate cancer patients previously treated with a GnRH agonist

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.

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.

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 treatment is compatible with diabetes and antithrombotic therapy in patients with prostate cancer

Introduction

Therapeutically induced androgen deficiency (AD) is a standard treatment for patients with prostate cancer, but it is often associated with various adverse effects (AEs) that may lead to discontinuation. Some AEs may depend on the patient's health condition, while others may be due to complications of the drug delivery method. Degarelix is a gonadotropin-releasing hormone (GnRH) antagonist widely used for the treatment of androgen-dependent prostate cancer. This study aimed to ascertain the following: 1) the compatibility of degarelix treatment with diabetes and 2) any specific causal associations of degarelix injections with increased blood clotting and antithrombotic therapy requirements.

Patients and methods

The medical records of 162 patients with prostate cancer who had undergone degarelix treatment were retrospectively examined. The association of a medical history of diabetes and anticoagulant co-treatment with degarelix treatment discontinuation was analyzed statistically.

Results

Rapid and significant decreases in prostate-specific antigen (PSA) levels during the course of degarelix treatment were detected for patients with prostate cancer regardless of clinical state. During the 27 months of treatment, 68 subjects (48%) ceased degarelix treatment, owing to several reasons, mainly financial issues. Among these subjects, 19 had diabetes, while 35 were treated with antithrombotics. Extensive statistical analysis indicated that there were no causal associations between degarelix treatment discontinuation and preexisting diabetes or antithrombotic therapy.

Conclusion

Our study suggests that preexisting diabetes and antithrombotic therapy were not significant factors for the discontinuation of degarelix treatment in patients with prostate cancer.