Therapeutic outcomes of the LHRH antagonists

Relugolix for the treatment of prostate cancer

INTRODUCTION

Androgen deprivation therapy consists of the cornerstone of prostate cancer medical treatment. Until recently, castration of hypothalamus-hypophysis-gonadal axial was based on injectable medical agents. A few years ago, a novel per os administered GnRH antagonist was approved leading testosterone to castration level. Relugolix was approved by FDA in 2020, and it is the first per os administered GnRH antagonist. The present study is a literature review of the efficacy, safety and clinical perspectives of relugolix.

AREAS COVERED

A literature narrative review was conducted using PubMed/MEDLINE, Scopus, and the Cochrane library. Studies written in English language, considering efficacy, safety and cost-effectiveness of relugolix compared with other androgen deprivation therapies were included in the review.

EXPERT OPINION

Recent studies have examined efficacy of relugolix revealing a testosterone suppression percentage of 78.4% after 48 weeks from treatment initiation. Moreover, relugolix has been associated with less major cardiovascular events as well as better rate of testosterone recovery after treatment completion compared with the GnRH agonists. However, there is no head-to-head trial comparing relugolix with injectable GnRH antagonists, so far. As a result, a trial comparing the methods of antagonists' administration should be performed in the future.

Comparative analysis of real-world data of frequent treatment sequences in metastatic prostate cancer

Background

The incidence of prostate cancer is increasing worldwide. A significant proportion of patients develop metastatic disease and are initially prescribed androgen deprivation therapy (ADT). However, subsequent sequences of treatments in real-world settings that may improve overall survival remain an area of active investigation.

Materials and methods

Data were collected from 384 patients presenting with de novo metastatic prostate cancer from 2011 to 2015 at a tertiary cancer center. Patients were categorized into surviving (n = 232) and deceased (n = 152) groups at the end of 3 years. Modified sequence pattern mining techniques (Generalized Sequential Pattern Mining and Sequential Pattern Discovery using Equivalence Classes) were applied to determine the exact order of the most frequent sets of treatments in each group.

Results

Degarelix, as the initial form of ADT, was uniquely in the surviving group. The sequence of ADT followed by abiraterone and docetaxel was uniquely associated with a higher 3-year overall survival. Orchiectomy followed by fosfestrol was found to have a unique niche among surviving patients with a long duration of response to the initial ADT. Patients who received chemotherapy followed by radiotherapy and those who received radiotherapy followed by chemotherapy were found more frequently in the deceased group.

Conclusions

We identified unique treatment sequences among surviving and deceased patients at the end of 3 years. Degarelix should be the preferred form of ADT. Patients who received ADT followed by abiraterone and chemotherapy showed better results. Patients requiring palliative radiation and chemotherapy in any sequence were significantly more frequent in the deceased group, identifying the need to offer such patients the most efficacious agents and to target them in clinical trial design.

Testosterone castration levels in patients with prostate cancer: Is there a difference between GnRH agonist and GnRH antagonist? Primary results of an open-label randomized control study

PURPOSE

To compare testosterone castration levels between patients treated with the gonadotropin-releasing hormone (GnRH) antagonist, degarelix, and GnRH agonist.

MATERIALS AND METHODS

Patients with prostate cancer (PCa) of a single outpatient clinic were randomized (2:1) to receive degarelix (group A) or GnRH agonist (group B). The study evaluated testosterone and prostate-specific antigen (PSA) levels, patients' age, Gleason score and the presence of metastases (nodal or bone). Testosterone and PSA levels were measured at 1st, 6th, 12th, and 18th months. Mann-Whitney test and Spearman correlation were used to investigate independent variable while standard multiple regression was performed to explore statistically significant correlations. Kruskal-Wallis test was used to compare testosterone levels at follow-up.

RESULTS

The study included 168 patients, 107 in group A and 61 in group B. Testosterone levels at 1st month were significantly lower in patients under GnRH antagonist than those receiving GnRH agonist (group A: 22 ng/dL vs. group B: 29 ng/dL, p=0.011). However, PSA values did not differ significantly between groups (group A: 0.130 ng/mL vs. group B: 0.067 ng/mL, p=0.261). In multivariate analysis, treatment with degarelix was an independent factor of lower testosterone levels at 1st month (p=0.013). Comparison of testosterone levels at 6, 12, and 18 months did not reveal any significant difference within each group.

CONCLUSIONS

In patients with PCa who are candidates for androgen deprivation therapy, the administration of GnRH antagonist seems to achieve significantly lower testosterone levels compared to treatment with GnRH agonist at 1st month of treatment.

Safety, pharmacokinetics, and pharmacodynamics of SHR7280, an oral gonadotropin-releasing hormone receptor antagonist, in healthy men: a randomized, double-blind, placebo-controlled phase 1 study

BACKGROUND

Gonadotropin-releasing hormone (GnRH) antagonists are a promising therapeutic approach for treating hormone-dependent prostate cancer. Currently, the mainstream GnRH antagonists are polypeptide agents administered through subcutaneous injection. In this study, we evaluated the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of SHR7280, an oral small molecule GnRH antagonist, in healthy men.

METHODS

This phase 1 trial was a randomized, double-blind, placebo-controlled, and dose-ascending study. Eligible healthy men were randomized in a 4:1 ratio to receive either oral SHR7280 tablets or placebo twice daily (BID) for 14 consecutive days. The SHR7280 dose was initiated at 100 mg BID and then sequentially increased to 200, 350, 500, 600, 800, and 1000 mg BID. Safety, PK, and PD parameters were assessed.

RESULTS

A total of 70 subjects were enrolled and received the assigned drug, including 56 with SHR7280 and 14 with placebo. SHR7280 was well-tolerated. The incidence of adverse events (AEs, 76.8% vs 85.7%) and treatment-related AEs (75.0% vs 85.7%), as well as the severity of AEs (moderate AEs, 1.8% vs 7.1%) were similar between the SHR7280 group and placebo group. SHR7280 was rapidly absorbed in a dose-dependent manner, with a median T_max of each dose group ranging from 0.8 to 1.0 h on day 14 and a mean t_1/2 ranging from 2.8 to 3.4 h. The PD results demonstrated that SHR7280 exhibited a rapid and dose-proportional suppression of hormones, including LH, FSH, and testosterone, with maximum suppression achieved at doses of 800 and 1000 mg BID.

CONCLUSIONS

SHR7280 showed an acceptable safety profile, as well as favorable PK and PD profiles within a dose range of 100 to 1000 mg BID. This study proposes a rationale for further investigation of SHR7280 as a potential androgen deprivation therapy.

TRIAL REGISTRATION

Clinical trials.gov NCT04554043; registered September 18, 2020.

Relugolix in the management of prostate cancer

INTRODUCTION

Relugolix is the first oral gonadotrophin-releasing hormone (GnRH) receptor antagonist. Based on the phase III HERO trial results, relugolix received Food and Drug Administration approval for adult patients with advanced prostate cancer (PCa).

AREAS COVERED

: We provide an overview of the preclinical and clinical development of relugolix and its role in the current treatment landscape of PCa.

EXPERT OPINION

Relugolix leads to rapid inhibition of testicular production of testosterone and its rapid recovery upon discontinuation. In the HERO trial, relugolix was associated with a superior cardiovascular safety profile compared to GnRH agonists. These attributes make relugolix a promising therapy for patients with pre-existing cardiovascular co-morbidities, those pursuing intermittent androgen deprivation therapy, and those who desire rapid testosterone recovery during "off-treatment" periods. In the HERO trial, very few patients received concomitant enzalutamide (n=17, 2.7%) or docetaxel (n<10, 1.3%). Safety of relugolix has not been established in combination with many androgen-receptor-axis targeted therapies (e.g. abiraterone, apalutamide), cabazitaxel, or lutetium Lu 177 vipivotide tetraxetan, which precludes its use in combination with these agents. In addition, being an oral drug, relugolix may also be associated with challenges of affordability, adherence, and compliance in this predominantly elderly population.

Relugolix: A new kid on the block among gonadotrophin-releasing hormone antagonists

Androgen-deprivation therapy (ADT) is the cornerstone of metastatic prostate cancer treatment. ADT can be achieved through surgical castration, or it may be induced either by gonadotrophin-releasing hormone (GnRH) agonists or GnRH antagonists. GnRH antagonists provide a more rapid castration alongside with a safer profile regarding adverse events. Degarelix is the sole GnRH antagonist used in clinical practice. Injection site reactions are the commonest adverse events related to the use of degarelix. Relugolix, a novel molecule, represents the first orally administered United States Food and Drug Administration approved GnRH antagonist, with clinical efficacy equal to that of the established ADT regimens. The main advantages of relugolix are the avoidance of the injection site reactions of GnRH antagonists such as degarelix alongside its patient-friendly oral administration. The aim of the present review article is to present novel data regarding the role of relugolix as ADT for the treatment of prostate cancer.

Abbreviations: ADT: androgen-deprivation therapy; FDA: United States Food and Drug Administration

miRNAs and androgen deprivation therapy for prostate cancer

Androgen deprivation therapy (ADT) is mainly used for the treatment of advanced, metastatic or recurrent prostate cancer (PCa). However, patients progress to ADT resistance and castration-resistant prostate cancer (CRPC) with a poor prognosis. Reliable validated markers of ADT resistance with proven clinical utility are necessary for timely correction of the therapy as well as for improvement of patient quality of life. MiRNAs involved in the ADT response and CRPC development via multiple mechanisms may act as biomarkers for patient outcomes. Available data on miRNAs associated with the ADT response (resistance and sensitivity) are summarized and analyzed in the manuscript, including analyses using bioinformatics resources. Molecular targets of miRNAs, as well as reciprocal relations between miRNAs and their targets, were studied using different databases. Special attention was dedicated to the mechanisms of ADT resistance and CRPC development, including testosterone, PI3K-AKT, VEGF pathways and associated genes. Several different approaches can be used to search for miRNAs associated with the ADT response, each of which focuses on the associated set of miRNAs - potential markers of ADT. The intersection of these approaches and combined analysis allowed us to select the most promising miRNA markers of the ADT response. Meta-analysis of the current data indicated that the selected 5 miRNAs (miRNAs - 125b, miR-21, miR-23b, miR-27b and miR-221) and 14 genes are involved in the regulation of key processes of CRPC development and represent the most promising predictors of the ADT response, further demonstrating their potential in combination therapy for advanced PCa.

Current and emerging gonadotropin-releasing hormone (GnRH) antagonists for the treatment of prostate cancer

Introduction:Androgen deprivation therapy (ADT) is currently the backbone treatment of metastatic prostate cancer and is also used in combination with external beam radiotherapy (EBRT). Castration may be achieved either by bilateral orchiectomy or by administration of LHRH agonists or GnRH antagonists.Areas covered: In this article, the authors assess the current and emerging role of GnRH antagonists for the treatment of prostate cancer focusing on oncological results and safety (i.e. cardiovascular risk). In addition, updated data regarding the first orally administered GnRH antagonist, relugolix, is presented.Expert opinion: Studies demonstrate that GnRH antagonists are at least equal with LHRH agonists in terms of testosterone suppression and PSA progression free survival with a major advantage being rapid testosterone suppression. Thus, the optimal group of patients included symptomatic metastatic prostate cancer patients especially if cardiovascular comorbidities or LUTS are also present. Emerging data regarding benefit of the use of GnRH antagonists in patients with concomitant cardiovascular disease are of great interest. Relugolix has emerged as the first orally administered GnRH antagonist able to achieve and maintain testosterone castration levels and it is associated with a profound reduction of major cardiovascular events.

Relugolix: a novel androgen deprivation therapy for management of patients with advanced prostate cancer

Androgen deprivation therapy (ADT) is the foundation of treatment for patients with locally advanced, recurrent and metastatic prostate cancer, most commonly using luteinizing releasing hormone (LHRH) agonists. More recently, a new approach to ADT has emerged with the development of gonadotropin-releasing hormone (GnRH) antagonists, which aim to overcome some of the potential adverse physiologic effects of LHRH agonists. This article focuses on the newest GnRH antagonist, relugolix - a once-daily treatment and the only oral GnRH antagonist that has now been approved for the treatment of advanced prostate cancer. In phase II and III studies, relugolix achieved rapid and sustained castration without the testosterone surge associated with LHRH agonists, thus avoiding the potential clinical consequences of tumor flare and the necessity for concomitant anti-androgen therapy. Relugolix also achieved rapid testosterone recovery, which may potentially reduce ADT-related adverse events and offer opportunities for combination and intermittent therapy strategies. Cardiovascular safety is a particular concern in men with prostate cancer and ADT further increases cardiovascular risk: indeed, LHRH agonists are required to have a drug label warning about an increased risk of cardiovascular disease. Data from the phase III HERO study demonstrate an improved cardiac safety profile for the GnRH antagonist relugolix compared with the LHRH agonist leuprolide, including a significantly reduced risk for a major adverse cardiovascular event. Taken together, the data indicate that relugolix may mitigate some of the cardiovascular concerns surrounding ADT and has the potential to become a new standard of care for men with prostate cancer. In summary, relugolix represents a novel and recently available prostate cancer management strategy, incorporating the mechanistic advantages of GnRH antagonists and the potential benefits of oral administration.