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

Medication related osteonecrosis (MRONJ) in the management of CTIBL in breast and prostate cancer patients. Joint report by SIPMO AND SIOMMMS

Background

Low-doses of bone modifying agents (LD-BMAs) compared to those used to treat bone metastases are used in breast or prostate cancer patients on adjuvant endocrine therapy to prevent Cancer Treatment Induced Bone Loss (CTIBL). Their use is associated with an increased risk of developing Medication-Related Osteonecrosis of the Jaw (MRONJ). However, there is not clarity about strategies aimed to minimize the MRONJ risk in cancer patients at different conditions as low- vs high-doses of BMA. This joint report from the Italian Societies of Oral Pathology and Medicine (SIPMO) and of Italian Society of Osteoporosis, Mineral Metabolism and Skeletal Diseases (SIOMMMS) aims to define the dental management of breast and prostate cancer patients with CTIBL under LD-BMAs, to reduce their risk to develop MRONJ.

Methods

This interdisciplinary SIPMO-SIOMMMS Expert Italian Panel reviewed the available international scientific literature and developed a set of recommendations to implement strategies of MRONJ prevention in breast (BC) and prostate cancer (PC) patients undertaking LD-BMAs to prevent CTIBL.

Results

The Expert Panel, after addressing some introductive topics (i.e., CTIBL and its management, pharmacology and pharmacodynamics of BMAs, definition and diagnosis of MRONJ), developed a joint report on the following five issues: a) prevention and dental management in cancer patients candidates to LD-BMAs, or under LD-BMAs; b) prophylactic drug holiday; c) MRONJ treatment; d) LD-BMAs therapeutic drug holiday; and e) restart of LD-BMA treatment after successful healing of MRONJ.Finally, ten key questions with answers were prepared and placed at the end of the document.

Conclusions

Despite obvious weaknesses of the available international literature, the Expert Panel recognized the need to tailor separate MRONJ preventive approach for breast and prostate cancer patients on adjuvant endocrine therapy who begin low-dose BMA therapy to prevent CTIBL and provided this practical guidance for bone specialists and oral healthcare providers. In view of a MRONJ risk for BC and PC patients receiving low-dose BMAs, which approximates that of patients with osteoporosis and other non-malignant diseases undergoing similar treatment schedules, the SIPMO-SIOMMMS Expert Panel recognizes the need for less stringent preventive strategies than those already developed for BC or PC patients with bone metastases taking HD-BMAs.

A 13-years pharmacovigilance analysis of novel hormonal agents in prostate cancer using the FDA adverse event reporting system database

BACKGROUND

Novel hormonal agents (NHAs), such as abiraterone, apalutamide, enzalutamide, and darolutamide, play a pivotal role in prostate cancer treatment. However, the toxicity spectrum of NHAs in the real-world has not been fully investigated. This study aims to analyze the adverse events (AEs) linked to NHAs.

METHODS

The safety profiles of NHAs were evaluated by using the United States FDA Adverse Event Reporting System (FAERS) database. Disproportionality analysis methods were applied to compare the safety signals of AEs associated with NHAs.

RESULTS

Our research has identified significant safety signals for all NHAs in vascular disorders, particularly noting elevated risk in the combined treatment involving docetaxel or poly ADP-ribose polymerase (PARP) inhibitors, specifically in blood and lymphatic system. Apalutamide, enzalutamide, and darolutamide displayed notable safety signals related to nervous system disorders, whereas abiraterone did not. Apalutamide exhibited specific AEs primarily linked to skin and subcutaneous tissue disorders, with severe AEs (SAEs) also concentrated in this category. Enzalutamide's specific AEs were predominantly associated with gastrointestinal disorders. Meanwhile, abiraterone's SAEs were mainly related to cardiac and hepatobiliary disorders.

CONCLUSION

Our study offers a comprehensive overview of safety signals associated with NHAs, providing a valuable reference for drug selection and future prospective research.

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.

The Effect of Androgen Deprivation Therapy on the Cardiovascular System in Advanced Prostate Cancer

Androgen deprivation therapy (ADT) is a mainstay treatment for metastatic prostate cancer, improving progression-free survival. ADT suppresses the production of testosterone and reduces circulating levels of the hormone. Luteinizing hormone-releasing hormone (LH-RH) agonists are the most commonly used ADT modality. They can be given alone or in combination with androgen synthesis inhibitors or androgen receptor antagonists. An estimated 40% of prostate cancer patients will receive ADT as part of their therapy during their lifetime. However, ADT has numerous adverse effects, including an increased cardiovascular risk that impacts quality of life. Relugolix is an alternative form of ADT. It is the only oral gonadotropin-releasing hormone antagonist, circumventing injection site reactions, making it easier for patients to take, and thus increasing compliance. Testosterone suppression with relugolix is excellent and testosterone recovery after discontinuation is rapid. This paper reviews the ADT and anti-androgen treatment options for men with prostate cancer and the cardiovascular effects of these therapies. There is accumulating evidence that cardiovascular risk with relugolix is lower than with other ADT medications and also lower than with androgen synthesis inhibitors and androgen receptor antagonists. This paper provides insight into the use of different ADT regimens based on the cardiovascular status and circumstances. It explores strategies to mitigate negative cardiovascular consequences and highlights the need for further study.

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.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

Lipid Membrane-Wrapped Zeolitic Imidazolate Framework-8 for Synergistic Chemotherapy and Photothermal Therapy to Target Prostate Cancer

Endocrine therapy is often used for advanced prostate cancer. However, with cancer progress, prostate cancer gradually resistant to hormone which lead to serious threatens to life of patients. Herein, a multifunctional synergistic core–shell nanoplatform is reported for improving the therapeutic effect of chemotherapy for advanced or metastatic prostate cancer, and reducing the risk of leakage of chemotherapy drugs. Particularly, Zeolitic imidazolate framework-8 (ZIF-8) is chosen as inner core to load doxorubicin, and the of liposomes which are embedded with IR780 iodide are used as outer shell, and further modified with target ligand that binds to luteinizing hormone releasing hormone receptor. The prepared nanocarrier exhibit satisfactory photothermal effect under near infrared laser irradiation, and the temperature increases to 60.8 °C within 6 min. Meanwhile, the elevated temperature accelerates the degradation of lipid shell, releasing ZIF-8 core to acidic microenvironment of tumor, and resulting in the release of doxorubicin. Moreover, in vivo and in vitro studies have shown the ZIF-D@ALIP core–shell nanoparticles can achieve targeted drug delivery, pH and NIR dual stimuli-responsive drug release, as well as chemotherapy and photothermal therapy synergistically on the tumor site. In addition, the problem of premature leakage and changes in the physicochemical properties of anticancer drugs are avoided under the protection of the outer shell structure. Therefore, the core–shell nanostructure proposes a new lipid membrane coating strategy to promote the effective targeting of prostate cancer cells or tissues and provides some insights in clinical treatment for advanced prostate cancer.

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.

Targeting signaling pathways in prostate cancer: mechanisms and clinical trials

Prostate cancer (PCa) affects millions of men globally. Due to advances in understanding genomic landscapes and biological functions, the treatment of PCa continues to improve. Recently, various new classes of agents, which include next-generation androgen receptor (AR) signaling inhibitors (abiraterone, enzalutamide, apalutamide, and darolutamide), bone-targeting agents (radium-223 chloride, zoledronic acid), and poly(ADP-ribose) polymerase (PARP) inhibitors (olaparib, rucaparib, and talazoparib) have been developed to treat PCa. Agents targeting other signaling pathways, including cyclin-dependent kinase (CDK)4/6, Ak strain transforming (AKT), wingless-type protein (WNT), and epigenetic marks, have successively entered clinical trials. Furthermore, prostate-specific membrane antigen (PSMA) targeting agents such as ¹⁷⁷Lu-PSMA-617 are promising theranostics that could improve both diagnostic accuracy and therapeutic efficacy. Advanced clinical studies with immune checkpoint inhibitors (ICIs) have shown limited benefits in PCa, whereas subgroups of PCa with mismatch repair (MMR) or CDK12 inactivation may benefit from ICIs treatment. In this review, we summarized the targeted agents of PCa in clinical trials and their underlying mechanisms, and further discussed their limitations and future directions.

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.