Gonadotropin-releasing hormone: an update review of the antagonists versus agonists

GnRH Peptide Antagonist: Comparative Analysis of Chemistry and Formulation with Implications for Clinical Safety and Efficacy

Overexpression of the gonadotropin-releasing hormone receptor (GnRH-R) plays a vital role in the advancement of reproductive malignancies such as ovarian, endometrial, and prostate cancer. Peptidomimetic GnRH antagonists are a substantial therapeutic development, providing fast and reversible suppression of gonadotropins by directly blocking GnRH-R. Unlike typical GnRH agonists, these antagonists prevent the early hormonal flare, have a faster onset of action, and have a lower risk of cardiovascular problems. These characteristics qualify GnRH antagonists as revolutionary therapy for diseases such as advanced prostate cancer, endometriosis, uterine fibroids, and in vitro fertilization procedures. Key GnRH peptide antagonists authorized by the regulatory agencies include Cetrorelix, Ganirelix, Abarelix, Degarelix, and Teverelix. Assisted reproductive technologies (ART) are dominated by Cetrorelix and Ganirelix, while Degarelix and Abarelix have shown significant promise in treating advanced prostate cancer. Teverelix appears as a next-generation GnRH antagonist with an ideal mix of efficacy and safety, showing promise in a variety of reproductive and hormone-dependent illnesses. This review investigates the pharmacological role of GnRH in reproductive physiology and its consequences in disease, emphasizing structural advances in third- and fourth-generation GnRH antagonists. All GnRH peptide-based antagonists were analyzed in detail for formulation strategy, pharmacokinetics, effectiveness, and safety. This review also emphasizes GnRH antagonists' clinical promise, providing insights into their evolution and the possibility for future research in developing safer, more effective treatments for complicated hormonal diseases.

Progress in the Stereoselective Synthesis Methods of Pyrrolidine-Containing Drugs and Their Precursors

The presented review systematizes and summarizes the data on the synthesis of pyrrolidine derivatives, which are precursors for obtaining drugs. Based on the analysis of published data, the most promising directions in the synthesis of biologically active compounds containing a pyrrolidine ring are identified. Stereoselective synthesis methods are classified based on the source of the pyrrolidine ring. The first group includes methods that use a pyrrolidine ring as the starting compound. The second group combines stereoselective methods of cyclization of acyclic starting compounds, which lead to optically pure pyrrolidine derivatives.

Nanomedicines in diagnosis and treatment of prostate cancers: an updated review

Prostate cancer (PC) is the third most common male cancer in the world, which occurs due to various mutations leading to the loss of chromatin structure. There are multiple treatments for this type of cancer, of which chemotherapy is one of the most important. Sometimes, a combination of different treatments, such as chemotherapy, radiotherapy, and surgery, are used to prevent tumor recurrence. Among other treatments, androgen deprivation therapy (ADT) can be mentioned, which has had promising results. One of the drawbacks of chemotherapy and ADT treatments is that they are not targeted to the tumor tissue. For this reason, their use can cause extensive side effects. Treatments based on nanomaterials, known as nanomedicine, have attracted much attention today. Nanoparticles (NPs) are one of the main branches of nanomedicine, and they can be made of different materials such as polymer, metal, and carbon, each of which has distinct characteristics. In addition to NPs, nanovesicles (NVs) also have therapeutic applications in PC. In treating PC, synthetic NVs (liposomes, micelles, and nanobubbles) or produced from cells (exosomes) can be used. In addition to the role that NPs and NVs have in treating PC, due to being targeted, they can be used to diagnose PC and check the treatment process. Knowing the characteristics of nanomedicine-based treatments can help design new treatments and improve researchers' understanding of tumor biology and its rapid diagnosis. In this study, we will discuss conventional and nanomedicine-based treatments. The results of these studies show that the use of NPs and NVs in combination with conventional treatments has higher efficacy in tumor treatment than the individual use of each of them.

Testosterone Recovery for Relugolix Versus Leuprolide in Men with Advanced Prostate Cancer: Results from the Phase 3 HERO Study

BACKGROUND

In the HERO study, relugolix demonstrated sustained testosterone suppression superior to that of leuprolide acetate (97% vs 89%; difference 7.9% [95% confidence interval, 4.1-12%; p < 0.001]).

OBJECTIVE

To analyze testosterone recovery in a prespecified subset of men from the HERO study not indicated to continue androgen deprivation therapy.

DESIGN, SETTING, AND PARTICIPANTS

Men (N = 934) were randomized (2:1) to receive relugolix 120 mg orally daily or leuprolide acetate injections every 12 wk for 48 wk.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Testosterone recovery was assessed in 184 men who completed 48 wk of treatment. During the 90-d recovery period, assessments included time to testosterone recovery (>280 ng/dl; ≥80% of baseline testosterone), serum levels of prostate-specific antigen and pituitary hormones, and adverse events.

RESULTS AND LIMITATIONS

The cumulative incidence rate of testosterone recovery to >280 ng/dl at 90 d following drug discontinuation was significantly higher in the relugolix cohort (n = 137) than in the leuprolide acetate cohort (n = 47; 54% vs 3.2%; nominal p = 0.002). The median time to testosterone recovery was faster following relugolix treatment than with leuprolide acetate treatment (86.0 d vs 112.0 d). Compared with leuprolide acetate, more men treated with relugolix achieved ≥80% of baseline testosterone levels (39% vs 2.1%). Men ≤65 yr and those with baseline testosterone greater than the median had a higher incident rate of testosterone recovery. Adverse events were generally similar between treatment groups. One limitation is the short testosterone recovery follow-up period.

CONCLUSIONS

Oral relugolix had faster and more complete recovery of testosterone to normal levels after treatment discontinuation than leuprolide acetate in a subset of men from the HERO study. The clinical implications of a faster testosterone recovery with relugolix may be significant for men being treated with androgen deprivation therapy and influence treatment decisions.

PATIENT SUMMARY

The male hormone testosterone is reduced during androgen deprivation therapy for prostate cancer. Reduced testosterone levels cause side effects, impacting patient quality of life. When treatment is stopped, the side effects lessen over time as the levels of testosterone come back to pretreatment range (testosterone recovery). In this study, we found that the time to testosterone recovery was faster with relugolix than with leuprolide acetate.

A Model-Informed Drug Development Approach to Design a Phase 3 Trial of Teverelix Drug Product in Advanced Prostate Cancer Patients with Increased Cardiovascular Risk

Teverelix drug product (DP) is a parenteral gonadotropin-releasing hormone (GnRH) antagonist that has been successfully tested in phase 2 trials for hormone-sensitive advanced prostate cancer (APC) and benign prostatic hyperplasia (BPH). In previous APC trials, teverelix DP was administered as intramuscular (IM) and subcutaneous (SC) injections, using a loading dose and (in a single trial) a maintenance dose. Our objective was to derive an optimal dosing regimen for phase 3 clinical development, using a pharmacometrics modeling approach. Data from 9 phase 2 studies (229 patients) was utilized to develop a population pharmacokinetic (PK) model that described the concentration profile accommodating both IM and SC routes of administration. A 2-compartment model with sequential first-order absorption (slow and fast) and lag times best described the PK profiles of teverelix following SC and IM administration. An indirect response model with inhibition of production rate was fit to describe testosterone (T) concentrations based on physiological relevance. The final population PK-pharmacodynamic model was used to conduct simulations of various candidate dosing regimens to select the optimal dosing regimen to achieve clinical castration (T < 0.5 ng/mL by day 28) and to sustain clinical castration for 26 weeks. Model simulation showed that a loading dose of 360 mg SC and 180 mg IM with a maintenance dose of 360 mg SC 6-weekly (Q6W) starting at day 28 can achieve a ≥95% castration rate up to 52 weeks. This dose regimen was selected for phase 3 clinical development, which includes cardiovascular safety assessment in comparison to a GnRH agonist.

Efficacy, tolerability, and safety of teverelix DP in patients with advanced prostate cancer: A multicenter, open-label, phase 2 trial

BACKGROUND

Teverelix drug product (DP) is a novel injectable gonadotropin-releasing hormone antagonist.

METHODS

An adaptive phase 2, open-label, multicenter trial was conducted in patients with advanced prostate cancer to evaluate the efficacy and safety of a combined subcutaneous (SC) and intramuscular (IM) loading dose regimen of teverelix DP of 120 mg SC + 120 mg IM (Group 1; N = 9) or 180 mg SC + 180 mg IM (Group 2; N = 41) administered at a single visit, followed by 6-weekly SC maintenance doses of 120 mg (Group 1) or 180 mg (Group 2), up to Day 168. The primary endpoint was the proportion of patients achieving castration levels with serum testosterone <0.5 ng/mL at Day 28 with a target castration rate of 90%. Injection sites were inspected by the investigator at every visit and reactions (ISRs) were proactively recorded.

RESULTS

The target castration rate was reached in Group 2 (97.5%) but not in Group 1 (62.5%). The castration rates were not maintained to Day 42 (Group 2: 82.5%; Group 1: 50.0%). Suppression of testosterone to castrate levels occurred rapidly (median time: 2 days for both groups). Suppression of testosterone, prostate-specific antigen, follicle-stimulating hormone, and luteinizing hormone was sustained throughout the treatment period, being more prominent with the higher dose. The adverse event (AE) profile was similar between groups. The most common AEs were injection-site induration (n = 40: 80.0%), injection-site erythema (n = 35: 70.0%), and hot flush (n = 21: 42.0%). Most ISRs were Grade 1.

CONCLUSION

Overall, the teverelix DP doses were generally well-tolerated but did not adequately maintain castration levels.

Prevalence of Preexisting Cardiovascular Diseases in Prostate Cancer Patients and Cardiac Risks of Hormonal Therapy

Background

Cardiovascular diseases (CVDs) are a prominent cause of mortality in prostate cancer patients. However, it has been reported that patients with preexisting CVDs are at greater risk. Literature on the magnitude of this problem in Saudi Arabia is lacking.

Objectives

To measure the prevalence of prostate cancer patients with preexisting CVDs in our population and to elucidate the possible risk factors of new cardiovascular events (CVEs) in patients who received androgen deprivation therapy (ADT).

Materials and Methods

This retrospective study included all patients newly diagnosed with prostate cancer at a tertiary hospital in the Eastern Province of Saudi Arabia from October 2008 to January 2019. The prevalence of preexisting cardiovascular diseases in these patients were determined. In addition, the incidence of new CVEs after initiating ADT was determined along with the risk factors for the same.

Results

The prevalence of preexisting CVD in our cohort was 16%. About 6% of the patients who received ADT had CVEs after a median follow-up of 39 months (IQR: 11-49 months). In the univariate analysis, hyperlipidemia (P = 0.002), stroke (P = 0.001), peripheral vascular disease (P = <0.001), cardiac patients with stents (P = <0.001), and cardiac patients without stent (P = <0.001) were significant risk factors of new CVEs after initiating ADT. However, in the multivariate regression analysis, only history of stroke and CVD (with or without stent) were found to be significant risk factors of new CVEs after initiating ADT (P = 0.01).

Conclusion

About one-fifth of the prostate cancer patients had preexisting CVDs. This study also found that luteinizing hormone-releasing hormone agonist could be a risk factor for new CVEs.

Gonadotropin-Releasing Hormone Receptor (GnRHR) and Hypogonadotropic Hypogonadism

Human sexual and reproductive development is regulated by the hypothalamic-pituitary-gonadal (HPG) axis, which is primarily controlled by the gonadotropin-releasing hormone (GnRH) acting on its receptor (GnRHR). Dysregulation of the axis leads to conditions such as congenital hypogonadotropic hypogonadism (CHH) and delayed puberty. The pathophysiology of GnRHR makes it a potential target for treatments in several reproductive diseases and in congenital adrenal hyperplasia. GnRHR belongs to the G protein-coupled receptor family and its GnRH ligand, when bound, activates several complex and tissue-specific signaling pathways. In the pituitary gonadotrope cells, it triggers the G protein subunit dissociation and initiates a cascade of events that lead to the production and secretion of the luteinizing hormone (LH) and follicle-stimulating hormone (FSH) accompanied with the phospholipase C, inositol phosphate production, and protein kinase C activation. Pharmacologically, GnRHR can be modulated by synthetic analogues. Such analogues include the agonists, antagonists, and the pharmacoperones. The agonists stimulate the gonadotropin release and lead to receptor desensitization with prolonged use while the antagonists directly block the GnRHR and rapidly reduce the sex hormone production. Pharmacoperones include the most recent GnRHR therapeutic approaches that directly correct the misfolded GnRHRs, which are caused by genetic mutations and hold serious promise for CHH treatment. Understanding of the GnRHR's genomic and protein structure is crucial for the most appropriate assessing of the mutation impact. Such mutations in the GNRHR are linked to normosmic hypogonadotropic hypogonadism and lead to various clinical symptoms, including delayed puberty, infertility, and impaired sexual development. These mutations vary regarding their mode of inheritance and can be found in the homozygous, compound heterozygous, or in the digenic state. GnRHR expression extends beyond the pituitary gland, and is found in reproductive tissues such as ovaries, uterus, and prostate and non-reproductive tissues such as heart, muscles, liver and melanoma cells. This comprehensive review explores GnRHR's multifaceted role in human reproduction and its clinical implications for reproductive disorders.

Triple therapy in metastatic hormone-sensitive prostate cancer

PURPOSE OF REVIEW

Over the last years, there have been striking changes in the management of metastatic hormone-sensitive prostate cancer (mHSPC) based on survival advantage of combining either a new hormonal agent (NHA) or docetaxel (D) with androgen deprivation therapy (ADT). Some of these studies primarily assessing doublet treatment included men who underwent concomitant or sequential treatment with D. Most recently, prospective randomized evidence emerged on this triplet strategy too. We aimed to outline the current data and ongoing trials evaluating the usage of the triplet therapy in male individuals with mHSPC.

RECENT FINDINGS

Phase III trials PEACE-1 and ARASENS showed that the upfront triplet treatment with ADT+D and either abiraterone acetate or darolutamide outperformed ADT+D in terms of survival, while severe toxicity was mainly driven by D. Importantly, prospective evidence comparing triplet vs. ADT+NHA is still lacking.

SUMMARY

Men with de novo high-volume disease benefit most from the triplet, while in cases with metachronous and/or low-volume disease, survival advantage is still disputable. As efficacy of ADT+NHA does not appear to be substantially amplified by combination with D, those men with a more favorable underlying tumor biology might mostly benefit from this doublet, also taking quality-adjusted survival into account.

Early biochemical outcomes following neoadjuvant/adjuvant relugolix with stereotactic body radiation therapy for intermediate to high risk prostate cancer

Introduction

Injectable GnRH receptor agonists have been shown to improve cancer control when combined with radiotherapy. Prostate SBRT offers an abbreviated treatment course with comparable efficacy to conventionally fractionated radiotherapy. Relugolix is a new oral GnRH receptor antagonist which achieves rapid, sustained testosterone suppression. This prospective study sought to evaluate early testosterone suppression and PSA response following relugolix and SBRT for intermediate to high prostate cancer.

Methods

Relugolix was initiated at least 2 months prior to SBRT. Interventions to improve adherence were not utilized. PSA and total testosterone levels were obtained prior to and 1-4 months post SBRT. Profound castration was defined as serum testosterone ≤ 20 ng/dL. Early PSA nadir was defined as the lowest PSA value within 4 months of completion of SBRT. Per prior trials, we examined the percentage of patients who achieved PSA level of ≤ 0.5 ng/mL and ≤ 0.2 ng/mL during the first 4 months post SBRT.

Results

Between July 2021 and January 2023, 52 men were treated at Georgetown with relugolix (4-6 months) and SBRT (36.25-40 Gy in 5 fractions) per an institutional protocol (IRB 12-1775). Median age was 71 years. 26.9% of patients were African American and 28.8% were obese (BMI ≥30 kg/m2). The median pretreatment PSA was 9.1 ng/ml. 67% of patients were ≥ Grade Group 3. 44 patients were intermediate- and 8 were high-risk. Patients initiated relugolix at a median of 3.6 months prior to SBRT with a median duration of 6.2 total months. 92.3% of patients achieved profound castration during relugolix treatment. Poor drug adherence was observed in 2 patients. A third patient chose to discontinue relugolix due to side effects. By post-SBRT month 4, 87.2% and 74.4% of patients achieved PSA levels ≤ 0.5 ng/ml and ≤ 0.2 ng/ml, respectively.

Discussion

Relugolix combined with SBRT allows for high rates of profound castration with low early PSA nadirs. We observed a 96% testosterone suppresion rate without the utilization of scheduled cues/reminders. This finding supports the notion that patients with localized prostate cancer can consistently and successfully follow an oral ADT protocol without daily reminders. Given relugolix's potential benefits over injectable GnRH receptor agonists, its usage may be preferred in specific patient populations (fear of needles, prior cardiovascular events). Future studies should focus on boundaries to adherence in specific underserved populations.

Oral gonadotrophin-releasing hormone (GnRH) antagonists: the continuing search for the ideal nonsurgical therapy of uterine fibroids with a cautionary tale

PURPOSE OF REVIEW

Uterine fibroids are very common with a prevalence of over 70%. They present a significant economic and psychological burden. A variety of nonsurgical treatments exist for its management encompassing hormonal and nonhormonal methods. Gonadotrophin-releasing hormone (GnRH) antagonists are a novel treatment for uterine fibroids. They cause a rapid reduction in endogenous GnRH, leading to a dose-dependent reduction in levels of oestradiol and progesterone, thus reduction in bleeding. The addition of hormones, estrogen, and progesterone, known as add-back therapy, helps curb the menopausal side effects. As such, they pose a potential long-term nonsurgical therapy for management of symptomatic fibroids.

RECENT FINDINGS

There are various uses of GnRH antagonists and the results from the clinical trials are promising. Caution needs to be taken when new treatment options are introduced with audit and data collection tools in place to assess effectiveness as well as any side effects.

SUMMARY

This article highlights the uses of GnRH antagonists in practice and reflects on previous novel treatments for fibroids with a focus on Ulipristal acetate. It states the importance of using audit tools and multiinstitutional databases to prevent and allow early discovery of issues such as those that encumbered Ulipristal.

Recent Advances in the Role of Autophagy in Endocrine-Dependent Tumors

Autophagy plays a complex role in several cancer types, including endocrine-dependent cancers, by fueling cellular metabolism and clearing damaged substrates. This conserved recycling process has a dual function across tumor types where it can be tumor suppressive at early stages but tumor promotional in established disease. This review highlights the controversial roles of autophagy in endocrine-dependent tumors regarding cancer initiation, tumorigenesis, metastasis, and treatment response. We summarize clinical trial results thus far and highlight the need for additional mechanistic, preclinical, and clinical studies in endocrine-dependent tumors, particularly in breast cancer and prostate cancer.

[Prostate cancer in older men : Special features of the diagnostics and treatment]

Prostate cancer is the most frequent cancer in men. For localized prostate cancer, surgery and radiotherapy are the standard treatment, with active surveillance also used in low-risk cases. For advanced/metastatic disease, androgen deprivation treatment is carried out. Further options include inhibitors of the androgen receptor axis and taxane-based chemotherapy. The avoidance of side effects should be considered, e.g., by dose adjustment. New options include poly(ADP-ribose) polymerase (PARP) inhibitors, and radioligand treatment. The existing guidelines only provide a few treatment recommendations for older patients; however, the treatment of older patients should primarily consider not only chronological age but also the patient's psychological and physical condition and preferences. In this context, the geriatric assessment represents an important instrument for determining the treatment strategy.

Safety, Pharmacokinetic and Pharmacodynamic Evaluation of Teverelix for the Treatment of Hormone-Sensitive Advanced Prostate Cancer: Phase 2 Loading-Dose-Finding Studies

Background and objectives: Teverelix drug product (DP) is a gonadotropin-releasing hormone antagonist in development for the treatment of patients with prostate cancer in whom androgen deprivation therapy is indicated. The aim of this paper is to present the results of five Phase 2 studies that assessed the pharmacokinetics, pharmacodynamics, efficacy and safety of different loading dose regimens of teverelix DP. Methods: Five single-arm, uncontrolled clinical trials were conducted in patients with advanced prostate cancer. The five different loading dose regimens of teverelix DP tested were (a) a single 90 mg subcutaneous (SC) injection of teverelix DP given on 3 consecutive days (Days 0, 1 and 2); (b) a single 90 mg intramuscular (IM) injection of teverelix DP given 7 days apart (Days 0 and 7); (c) a single 120 mg SC injection of teverelix DP given on 2 consecutive days (Days 0 and 1); (d) 2 × 60 mg SC injections of teverelix DP given on 3 consecutive days (Days 0, 1 and 2), and (e) 2 × 90 mg SC injections of teverelix DP given on 3 consecutive days (Days 0, 1 and 2). The primary efficacy parameter was the duration of action of an initial loading dose regimen in terms of suppression of testosterone to below the castration level (0.5 ng/mL). Results: Eighty-two patients were treated with teverelix DP. Two regimens (90 mg and 180 mg SC on 3 consecutive days) had a mean duration of castration of 55.32 days and 68.95 days with >90% of patients having testosterone levels < 0.5 ng/mL at Day 28. The mean onset of castration for the SC regimens ranged from 1.10 to 1.77 days, while it was slower (2.4 days) with IM administration. The most common adverse event (AE) was injection site reaction. No AEs of severe intensity were reported. Conclusions: Teverelix DP is safe and well tolerated. Castrate levels of testosterone can be rapidly achieved following the subcutaneous injection of teverelix DP on 3 consecutive days. Streamlining of the administration of the loading dose and identifying a suitable maintenance dose will be investigated in future trials.

Use of oral GnRH antagonists combined therapy in the management of symptomatic uterine fibroids

Uterine fibroids have an impact on women’s lives due to their high prevalence, physical symptoms, their consequences on patients’ emotional and psychological well-being and loss of work productivity. The choice of therapeutical approaches varies depending on several factors, and therefore should be applied individually. Currently, there is an unmet need for good, reliable, uterine-sparing options. The oral GnRH antagonists (Elagolix, Relugolix, Linzagolix) represent a new alternative for the medical management of hormone-dependent gynaecological diseases such as uterine fibroids or endometriosis. They rapidly bind to the GnRH receptor, block endogenous GnRH activity and directly suppress LH and FSH production, avoiding unwanted flare-up effects. Some GnRH antagonists are marketed in combination with hormone replacement therapy add-back to counteract hypo-oestrogenic side effects. According to the registration trials, once-daily GhRH antagonist combination therapy results in a significant reduction in menstrual bleeding, as compared with placebo, and preserves bone mineral density, for up to 104 weeks. Further studies in the long term are needed to evaluate the whole impact of medical treatment of uterine fibroids on the management of this common women’s disease.

[New treatment approaches for and ongoing trials in metastatic hormone-sensitive prostate cancer]

BACKGROUND

For many years, therapy for metastatic hormone-sensitive prostate cancer (mHSPC) was dominated by monotherapy using androgen deprivation therapy (ADT). With the demonstration of survival benefit with intensified systemic therapy from the CHAARTED and STAMPEDE trials, this has fundamentally changed. We analyzed the phase III trials that led to the change in therapy in mHSPC. In addition, we summarized ongoing trials in mHSPC.

OBJECTIVES

The ongoing studies and current data on systemic therapy in mHSPC were analyzed.

RESULTS

Monotherapy with ADT is no longer considered the standard therapy for mHSPC. Combination therapy with ADT and novel androgen receptor targeting agents (ARTAs: abiraterone, apalutamide, enzalutamide) is now the established standard option. The added value of further intensification of therapy was demonstrated in the first trials of triple therapy with ADT + docetaxel + darolutamide or abiraterone in mHSPC. Current studies are also investigating new forms of therapy. Lutetium177-PSMA radioligand therapy is an established standard in metastatic castration-resistant prostate cancer (mCRPC) and is currently being evaluated in combination with ADT + ARTA in mHSPC. The use of PARP inhibitors (PARPi) have been established in mCRPC. Current studies are showing early evidence of benefit from novel combination therapies of PARPi + ARTA, which represent a further expansion of the therapeutic landscape. Experimental therapies are testing another combination, such as an AKT inhibitor with ARTA in patients with PTEN (phosphatase and tensin homolog) loss. Based on the proof of principle in mCRPC, this combination is now being evaluated in earlier stage mHSPC. Other experimental therapies in clinical testing include inhibitors of cyclin dependent kinases (CDK).

CONCLUSIONS

Combination therapies are the current standard of care for mHSPC, with the combination of ADT + ARTA dominating. Preliminary results underline the importance of further intensification of therapy by means of triple therapy. However, novel combinations with radioligand therapy or PARP inhibitors are also promising in the treatment of mHSPC. Preliminary results show the principle efficacy of AKT inhibitors in patients with PTEN loss, which similar to therapy with CDK4/6 inhibitors still have to prove their clinical relevance in randomized trials.

The Treatment of Metastatic, Hormone-Sensitive Prostatic Carcinoma

BACKGROUND

For many years, the standard treatment of metastatic, hormone-sensitive prostatic carcinoma (mHSPC) was androgen deprivation therapy (ADT) alone. By lowering the testosterone level into the castration range, ADT deprives the tumor of a key growth factor.

METHODS

For this article, we evaluated the treatment recommendations contained in national and international guidelines (German S3 guidelines and those of the European Society for Medical Oncology [ESMO], European Association of Urology [EAU], and National Comprehensive Cancer Network [NCCN]), as well as pertinent publications revealed by a PubMed search and the congress abstracts of the ESMO and of the American Society of Clinical Oncology [ASCO].

RESULTS

The past few years have witnessed fundamental changes in the treatment of mHSPC. Treatment intensification with docetaxel or with the new drugs directed against the androgen receptor signal pathway (abiraterone, apalutamide and enzalutamide) has been found to lower mortality by 19-40% and is now an integral component of first-line therapy. Relevant new findings have also been obtained with threefold combinations of ADT, docetaxel, and abiraterone or darolutamide. For patients with a light tumor burden, local radiotherapy of the primary tumor improves the probability of survival at 3 years by 8% (45.4 versus 49.1 months, difference 3.6 months; 95% confidence interval, 1.0 to 6.2 months).

CONCLUSION

The treatment of mHSPC is constantly changing. Phase III trials that are now in the recruitment stage, as well as our continually improving understanding of the underlying molecular-pathological mechanisms, will be altering the treatment landscape still further in the years to come.

Emerging hormonal agents for the treatment of prostate cancer

INTRODUCTION

Prostate cancer is the most common solid organ malignancy in men in the United States. Until recently, treatment options for men with metastatic disease were limited and patients faced poor outcomes with minimal alternatives. The landscape of prostate cancer treatment has transformed and taken shape over the last 20 years with novel hormonal and non-hormonal therapeutics that have demonstrated significant improvement in survival. However, patients with advanced disease still face imminent progression on hormone blockade therapy.

AREAS COVERED

There is a significant market opportunity to devise novel, more potent agents for patients with hormone-resistant disease. Here we review the existing treatment options in men with advanced prostate cancer, the market opportunity within this field, goals of current research, and the novel agents under investigation, including androgen receptor degraders, testosterone synthesis pathway inhibitors, DNA-binding domain and N-terminal domain antagonists, and the combination of hormonal and non-hormonal agents.

EXPERT OPINION

Combination therapy regimens and novel agents targeting alternative binding domains of the androgen receptor are of great interest, as they may overcome resistance mechanisms and hold promise as the future of advanced prostate cancer treatment.

Relugolix and elagolix directly inhibit leiomyoma extracellular matrix production in 2-dimesnional and 3-dimensional cell cultures

OBJECTIVE

To determine the effect relugolix and elagolix have on the production of extracellular matrix (ECM) proteins in human leiomyoma cells.

DESIGN

Laboratory study.

SETTING

University hospital.

PATIENT(S) OR ANIMALS

None. January 5, 2022 Cell culture, protein analysis, immunohistochemistry.

MAIN OUTCOME MEASURE(S)

Production of GnRHR, COL1A1, FN1, VCAN, p-ERK, & ERK in treated/untreated leiomyoma cells.

RESULTS

100 nM relugolix resulted in decreased production of COL1A1 at 24 (1.78 0.06-fold; P < .05) and 48 hours (1.92 0.14-fold; P < .05). Elagolix treatment resulted in a decrease in COL1A1 production at 24 but not 48 hours. In 2D and 3D, 100 nM relugolix resulted in decreased production of FN1 at 24 (1.7 ± 0.07-fold; P < .05) and 48 hours (1.8 ± 0.07-fold; P < .05); 100 nM elagolix resulted in decreased production of FN1 at 24 (1.7 ± 0.14-fold; P < .05) and 48 hours (2.0 ± 0.09-fold; P < .05). For cells treated with relugolix 100 nM resulted in decreased VCAN production by 48 hours (0.66 ± 0.07-fold; P < .05). Contrary to our 3D data, 2D elagolix-treated cells demonstrated a decrease in VCAN production that was identified only at 24 hours. For GnRHR, no significant difference between the drugs was seen at 24 hours; at 48 hours production was only significantly decreased for relugolix (P < .05). Comparing both drugs, there was a significant difference in the concentration of p-ERK to ERK at 24 hours (P < .05); there was no difference by 48 hours.

CONCLUSIONS

Our findings demonstrated that treatment with either drug can 1) decrease ECM protein production and 2) inhibit the MAPK pathway.

Functional analysis of GCNT3 for cell migration and EMT of castration-resistant prostate cancer cells

Castration-resistant prostate cancer (CRPC) is a malignant tumor that is resistant to androgen deprivation therapy. Treatments for CRPC are limited, and no diagnostic markers are currently available. O-glycans are known to play an important role in cell proliferation, migration, invasion, and metastasis of cancer cells. However, the differences in the O-glycan expression profiles for normal prostate cancer (PCa) cells compared to CRPC cells have not yet been investigated. In this study, the saccharide primer method was employed to analyze the O-glycans expressed in CRPC cells. Expression levels of core 4-type O-glycans were significantly increased in CRPC cells. Furthermore, the expression level of N-Acetylglucosaminyltransferase 3 (GCNT3), a core 4-type O-glycan synthase gene, was increased in CRPC cells. The expression of core 4-type O-glycans and GCNT3 was presumed to be regulated by androgen deprivation. GCNT3 knockdown induced cell migration and epithelial-mesenchymal transition (EMT). These observations elucidate the mechanism of acquisition of castration resistance in PCa and offer new possibilities for the development of diagnostic markers and therapeutic targets in the treatment of PCa.

Peptide Hormones in Medicine: A 100-Year History

Abstract

This review is devoted to the 100-year history of the investigation of peptide hormones and the creation of drugs on their basis, starting from the insulin discovery and its introduction into a medical practice in 1921. The basic groups of the peptide hormones are discussed: neurohypophyseal hormones, hypothalamic releasing hormones, incretins, insulin, adrenocorticotropic hormone (ACTH), and calcitonin. The first therapeutic agents based on the peptide hormones were created by a traditional approach that involved the isolation of peptides from animal tissues, their purification to individual compounds, determination of their primary structure, their chemical synthesis or their deep purification, and the creation of a pharmaceutical substance. A modern approach to creation of peptide hormone drugs is based on their consideration as ligands of the corresponding cellular receptors and the use of computer modeling, efficient synthesis methods, and high-throughput screening. The combination of these methods enabled the development of analogs which would be more active than the corresponding natural compounds, exhibit other activities in addition to the hormonal regulation, and be resistant to biodegradation. Such therapeutic agents have been designed on the basis of agonistic and antagonistic analogs of somatostatin and luliberin, and have found wide application in hormonal regulation and cancer treatment. Over the past two decades, the glucagon-like peptide (GLP-1) has been intensively investigated as a potential therapeutic agent. In our review, we describe modifications which resulted in the most highly effective long-acting drugs. Now, natural hormones and their analogs are widely present in the pharmaceutical market.

Androgen deprivation therapy and cardiovascular risk in prostate cancer

INTRODUCTION

Androgen-deprivation therapy (ADT), with or without palliative local treatments, is the standard of care for many patients with locally-advanced and/or metastatic prostate cancer. However, the possible cardiovascular (CV) risks associated with gonadotropin-releasing hormone (GnRH) antagonists and agonists continue to be the subject of concern, especially in a patient population that may already be at increased CV risk.

EVIDENCE ACQUISITION

The present review provides a narrative summary of the evidence regarding the CV risks associated with GnRH antagonists and agonists from randomized clinical trials (RCTs), real-world evidence, and meta-analyses.

EVIDENCE SYNTHESIS

From RCTs, it appears clear that there is a direct class effect for CV risk in patients with prostate cancer being administered GnRH agonists and antagonists, with the latter being associated with reduced CV risk. Real-world data and the available meta-analyses largely indicate that CV risk is lower with GnRH antagonists than with GnRH agonists.

CONCLUSIONS

A review of the pathophysiological mechanisms of gives further support to the possibility that GnRH antagonists are associated with lower CV risk than agonists. It can be highlighted that when treating patients with advanced or metastatic prostate cancer it is important to screen for underlying comorbidities prior to choosing the most appropriate therapy; moreover, patients should be closely monitored for factors associated with CV risk in order to optimize outcomes. Further studies are needed to define the most appropriate treatment according to the individual patient characteristics.

Androgen Flare after LHRH Initiation Is the Side Effect That Makes Most of the Beneficial Effect When It Coincides with Radiation Therapy for Prostate Cancer

Simple Summary

Prostate cancer tumor growth is stimulated by androgens. Surgical castration or medical castration using long-acting luteinizing hormone-releasing hormone (LHRH) agonists or antagonists is the backbone of the treatments of metastatic disease. Treatment of locally advanced prostate cancer was accomplished with radiation therapy alone until multiple studies showed that combining radiation therapy with LHRH agonists results in significant survival benefit. While the goal of the use of LHRH agonists was to suppress testosterone levels during radiation, we show, through review of previous studies, that survival benefit was achieved only when LHRH was initiated during the course of radiation, and thus androgen flare during the first 1–3 weeks after the initiation of LHRH is most likely the reason for higher survival. Androgens drive tumor cells into mitosis, and mitotic death is the dominant mechanism of tumor cell kill by radiation.

Abstract

Treatment of metastatic prostate cancer was historically performed via bilateral orchiectomy to achieve castration. An alternative to surgical castration is the administration of subcutaneous recombinant luteinizing hormone-releasing hormone (LHRH). LHRH causes the pituitary gland to produce luteinizing hormone (LH), which results in synthesis and secretion of testosterone from the testicles. When LHRH levels are continuously high, the pituitary gland stops producing LH, which results in reduced testosterone production by the testicles. Long-acting formulations of LHRH were developed, and its use replaced surgical orchiectomy in the vast majority of patients. Combining LHRH and radiation therapy was shown to increase survival of prostate cancer patients with locally advanced disease. Here, we present a hypothesis, and preliminary evidence based on previous randomized controlled trials, that androgen surge during radiation, rather than its suppression, could be responsible for the enhanced prostate cancer cell kill during radiation. Starting LHRH agonist on the first day of radiation therapy, as in the EORTC 22863 study, should be the standard of care when treating locally advanced prostate cancer. We are developing formulations of short-acting LHRH agonists that induce androgen flare, without subsequent androgen deprivation, which could open the door for an era in which locally advanced prostate cancer could be cured while patients maintain potency.

A Review of GnRH Antagonists as Treatment for Abnormal Uterine Bleeding-Leiomyoma (AUB-L) and Their Influence on the Readiness of Service Members

INTRODUCTION

Not too long ago, Lupron Depot® (leuprolide acetate), an injectable gonadotropin-releasing hormone (GnRH) agonist, was the only Food and Drug Administration (FDA) approved GnRH analog used to clinically treat abnormal uterine bleeding associated with uterine leiomyoma (AUB-L) when second-line medical management was warranted; however, the FDA has now approved elagolix and relugolix, GnRH antagonists, to be treatment options as well. This is a review of GnRH antagonists for the management of uterine fibroids reviewing their treatment efficacy, side effect profile, and current use in military medicine.

METHODS

This is a review of studies from multiple electronic databases (Pubmed, ACOG, FDA, U.S. Military Guidelines) published between 1990 and 2021. Keywords used for the search include GnRH antagonist, elagolix, relugolix, uterine leiomyoma, and abnormal uterine bleeding. Our inclusion criteria for articles reviewed were: systematic reviews with the listed keywords, multicenter randomized trials, and meta-analyses. The DODI on Medical Standards for Medical Service, Air Force Aerospace Medicine Waiver Guide, Navy Guidance Aeromedical Reference and Waiver Guide, and the Army Regulation 40-501 Standards of Medical Fitness were used to review the military standards and current restrictions placed on service members.

RESULTS

Thirty-three articles were reviewed and summarized.

CONCLUSION

Uterine leiomyoma can impact service members' eligibility and fitness for duty. The oral administration of elagolix and relugolix adds convenience to this drug class through its oral administration while lengthening the duration of treatment up to 24 months. All military medical facilities should advocate for the well-being of their service members by stocking all options available. Health care providers should collaborate with patients in making the best therapy choice that is suited for their lifestyle and military occupation.

Sequencing of Systemic Therapies in the Management of Advanced Prostate Cancer in India: a Delphi-Based Consensus

INTRODUCTION

With the availability of an increasing number of therapeutic options for advanced prostate cancer (APC), optimal sequencing and combination of therapies have emerged to be the areas of challenges. In the Indian context, there is a dearth of consensus recommendations to guide clinicians regarding optimal sequencing of therapy in APC management. A Delphi-based consensus regarding optimal therapy sequencing in APC management was developed by an expert panel of medical oncologists from across India.

METHODS

An expert scientific committee of 11 medical oncologists and an expert panel of 53 medical oncologists from India constituted the panel for the Delphi consensus. In the first phase, a questionnaire with 41 clinical statements was developed in several critical controversial areas in APC treatment. In the second phase, 29 clinical statements were reworked and sent to eight experts to obtain their opinions on best practices. The consensus ratings were based on a 9-point Likert scale. Based on the overall response, statements with a mean score of ≥ 7 with 1 outlier were considered as "consensus."

RESULTS

Degarelix was the preferred androgen deprivation therapy (ADT). While ADT plus docetaxel was the preferred option for metastatic castrate-sensitive/naïve prostate cancer patients with high-volume disease, ADT with abiraterone was the preferred choice for low-volume disease. Docetaxel was the preferred first-line treatment option in men who received ADT alone in the castrate-sensitive/naïve setting. For patients progressing on or after docetaxel for metastatic castrate-resistant prostate cancer (without prior abiraterone or enzalutamide), the experts reached a consensus on the use of enzalutamide as the preferred second-line treatment option. No consensus was reached for the third-line treatment options.

CONCLUSION

This article is intended to serve as a guide to help clinicians discuss with their patients as part of the shared and multidisciplinary decision-making for improved APC management in India.

Lysine Acetyltransferases and Their Role in AR Signaling and Prostate Cancer

The development and growth of a normal prostate gland, as well as its physiological functions, are regulated by the actions of androgens through androgen receptor (AR) signaling which drives multiple cellular processes including transcription, cellular proliferation, and apoptosis in prostate cells. Post-translational regulation of AR plays a vital role in directing its cellular activities via modulating its stability, nuclear localization, and transcriptional activity. Among various post-translational modifications (PTMs), acetylation is an essential PTM recognized in AR and is governed by the regulated actions of acetyltransferases and deacetyltransferases. Acetylation of AR has been identified as a critical step for its activation and depending on the site of acetylation, the intracellular dynamics and activity of the AR can be modulated. Various acetyltransferases such as CBP, p300, PCAF, TIP60, and ARD1 that are known to acetylate AR, may directly coactivate the AR transcriptional function or help to recruit additional coactivators to functionally regulate the transcriptional activity of the AR. Aberrant expression of acetyltransferases and their deregulated activities have been found to interfere with AR signaling and play a key role in development and progression of prostatic diseases, including prostate cancer (PCa). In this review, we summarized recent research advances aimed at understanding the role of various lysine acetyltransferases (KATs) in the regulation of AR activity at the level of post-translational modifications in normal prostate physiology, as well as in development and progression of PCa. Considering the critical importance of KATs in modulating AR activity in physiological and patho-physiological context, we further discussed the potential of targeting these enzymes as a therapeutic option to treat AR-related pathology in combination with hormonal therapy.

Depot Pure GnRH Antagonist for Long-term Treatment of Ovarian Hyperthecosis Monitored by Multisteroid LCMS Profiling

Ovarian hyperthecosis (OHT), severe hyperandrogenism after menopause in the absence of ovarian or adrenal tumors, is usually treated by surgical excision. We report a 58-year-old woman presenting with severe hyperandrogenism (serum testosterone 15.7-31.0 nmol/L, normal female <1.8 nmol/L) with menopausal gonadotropins and virilization but no adrenal or ovarian lesions. Multisteroid profiling by liquid chromatography mass spectrometry (LCMS) of adrenal and ovarian vein samples identified strong gradients in the left ovarian vein (10- to 30-fold vs peripheral blood in 17OHP₄, 17 hydroxyprogesterone, 17 hydroxypregnenolone, androstenedione, testosterone, dehydroepiandrosterone) but the right ovarian vein could not be cannulated with the same findings in a second ovarian vein cannulation. OHT diagnosis was confirmed by an injection of a depot pure gonadotropin-releasing hormone (GnRH) antagonist (80 mg Degarelix, Ferring) producing a rapid (<24 hour) and complete suppression of ovarian steroidogenesis as well as serum luteinizing hormone and follicle-stimulating hormone lasting at least 8 weeks, with reduction in virilization but injection site reaction and flushing and vaginal spotting ameliorated by an estradiol patch. Serum testosterone remained suppressed at 313 days after the first dose despite recovery of menopausal gonadotropins by day 278 days. This illustrates use of multisteroid LCMS profiling for confirmation of the OHT diagnosis by ovarian and adrenal vein sampling and monitoring of treatment by peripheral blood sampling. Injection of a depot pure GnRH antagonist produced rapid and long-term complete suppression of ovarian steroidogenesis maintained over 10 months. Hence a depot pure GnRH antagonist can not only rapidly confirm the OHT diagnosis but also induce long-term remission of severe hyperandrogenism without surgery.

Differences in sex hormone recovery profile after cessation of 12-week gonadotropin-releasing hormone antagonist versus agonist therapy

BACKGROUND

Pharmacobiological behavior differs between gonadotropin-releasing hormone (GnRH) antagonists and GnRH agonists. However, reliable evidence clarifying the difference between them is limited.

OBJECTIVES

We aimed to elucidate the difference in recovery profile between GnRH antagonist (degarelix) and GnRH agonist (leuprorelin acetate or goserelin acetate) as short-term (12 weeks) neoadjuvant androgen deprivation therapy (ADT) prior to 125I-transperineal prostate brachytherapy (TPPB) for localized prostate cancer.

MATERIALS AND METHODS

This study was initially designed as a single-center, prospective, open-label, randomized controlled trial. The primary endpoint was a serum testosterone level above the castration range (>50 ng/dl) after the cessation of 12-week neoadjuvant ADT (GnRH antagonist or GnRH agonists). All patients underwent 12 weeks of neoadjuvant ADT. The recovery profiles of hormones, prostate-specific antigen, total prostate volume (TPV), bone mineral density, and quality of life scores were investigated.

RESULTS

Testosterone recovery duration after the last injection was significantly longer in the GnRH antagonist arm than in the GnRH agonist arm (median, 27.3 vs. 4.8 weeks, p < 0.001). The serum levels of luteinizing hormone and follicle-stimulating hormone in the GnRH antagonist arm also remained significantly lower than those in the GnRH agonist arm between 16 and 24 weeks (p < 0.01). Meanwhile, reduction in TPV at the time of TPPB was comparable between both arms (p = 0.128). There were also no significant between-arm differences in the International Prostate Symptom Score and the International Index of Erectile Function scores.

DISCUSSION AND CONCLUSION

The recovery patterns of hormonal profiles after short-term (12 weeks) neoadjuvant ADT differ between GnRH antagonists and GnRH agonists. The choice between these drugs matters and may have a clinical impact depending on the primary objective of ADT.

Bilateral Orchidectomy Revisited in Management of Metastatic Hormone-Sensitive Prostate Cancer

INTRODUCTION

Androgen deprivation therapy (ADT) is a well-established treatment for metastatic hormone-sensitive prostate cancer (mHSPC). It includes either bilateral orchiectomy or medical castration in form of luteinizing hormone-releasing hormone (LHRH) agonist or antagonist. We conducted this study to compare surgical and medical castration in terms of time to progression (TTP) to castration resistant prostate cancer.

METHODS

Patients with mHSPC underwent either bilateral orchidectomy or medical castration by either LHRH agonist or by antagonist from November 2016 to May 2018 in our institution. Initial PSA and baseline imaging either magnetic resonance imaging (MRI) or positron emission tomography-computed tomography (PET CT) finding were recorded. Serum PSA, testosterone, and FSH were repeated every 3 months till 1 year. All enrolled patients were followed up with a bone scan/MRI/ PET CT at 6 months and 12 months. End point of study was progression of disease and death of patient.

RESULTS

Mean nadir PSA (ng/ml) after treatment was 4.7 and 9.8 in surgical and medical group respectively, whereas mean time to the nadir PSA was 8.7 and 8.8 respectively with no statistically significant difference. Mean TTP was 13.9 months in bilateral orchidectomy group and 13.8 months in medical castration group (chi-square 0.003, p value 0.958).

CONCLUSION

There was no significant difference in time to progression between bilateral orchidectomy and medical castration. Considering nadir PSA level, better quality of life, patient compliance, reduced hospital visit, and decrease in cost of treatment, bilateral orchidectomy may be a better treatment option especially in developing countries.

Enzalutamide-Induced Upregulation of PCAT6 Promotes Prostate Cancer Neuroendocrine Differentiation by Regulating miR-326/HNRNPA2B1 Axis

Our previous studies have demonstrated that Enzalutamide-induced upregulation of long non-coding RNA p21 (lncRNA-p21) facilitates prostate cancer (PCa) neuroendocrine differentiation (NED). Given the important role of lncRNAs in PCa pathogenesis, and given that lots of lncRNAs are dys-regulated in neuroendocrine PCa (NEPC) patients, we next explored the biological function and underlying mechanism of lncRNA-PCAT6 (PCAT6) in mediating Enzalutamide-induced NED. The level of PCAT6 in Enzalutamide-treated PCa cells and NEPC samples were assessed using quantitative RT-PCR (qPCR). The effect of PCAT6 on PCa cell proliferation, invasion, and NED was evaluated through CCK-8, transwell, qPCR, western blot analysis, Xenograft mouse model, and in vivo lung metastasis model. We found that PCAT6 was highly expressed in NE-like cells (PC3, DU145, and NCI-H660) compared with androgen-sensitive LNCaP cells. PCAT6 was also highly expressed in NEPC tissues. Enzalutamide treatment resulted in a significant increase of PCAT6 level in a dose- and time-dependent fashion. Functionally, PCAT6 overexpression promoted NED of C4-2 cells, as evidenced by an increased expression of NE markers (NSE, ChgA, and SYP), whereas PCAT6 knockdown in NCI-H661 cells repressed NED. Furthermore, PCAT6 overexpression promoted PCa cell proliferation and invasion in vitro and in vivo. Mechanistically, PCAT6 functioned as competing endogenous (ce) RNA via absorbing miR-326, thus resulting in a de-suppression of Hnrnpa2b1 target gene. The current results demonstrate that PCAT6 acted as a tumor activator in PCa progression by sponging miR-326 and increasing Hnrnpa2b1 expression and that the PCAT6/miR-326/Hnrnpa2b1 signaling might be a new therapeutic target for PCa.

Considerations for the use of gonadotropin-releasing hormone agonists and antagonists in patients with prostate cancer

Prostate cancer is the second most common cause of cancer-related deaths in men, representing a major source of morbidity and mortality. Androgen deprivation therapy is the primary treatment for patients with advanced prostate cancer at disease presentation, which can be achieved either with surgical or chemical castration. The development of gonadotropin-releasing hormone agonists revolutionized the treatment of advanced prostate cancer, replacing the need for surgical castration. Agonists downregulate gonadotropin-releasing hormone agonist receptors in the pituitary gland, and thus decrease the release of luteinizing hormone and testosterone. Although agonists are a common therapeutic option to date, their use is associated with testosterone surges, metabolic dysfunction and an increase in the risk of cardiovascular disease; they might contribute to tumor flares and potentially an increase in non-cancer mortality. More recently, gonadotropin-releasing hormone antagonists have entered the prostate cancer treatment landscape. Unlike agonists, antagonists directly inhibit the androgen receptor in the pituitary gland, and thus do not cause initial testosterone surges. In this article, we provide a concise review of the mechanism of actions, safety and efficacy of the approved agonists and antagonists for prostate cancer treatment.

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.

Differential Impact of Gonadotropin-releasing Hormone Antagonist Versus Agonist on Clinical Safety and Oncologic Outcomes on Patients with Metastatic Prostate Cancer: A Meta-analysis of Randomized Controlled Trials

CONTEXT

Androgen deprivation therapy is the mainstay treatment of metastatic prostate cancer, achieved mainly by gonadotropin-releasing hormone (GnRH) agonists or antagonists.

OBJECTIVE

To investigate the differential impact of GnRH agonists and antagonists on clinical safety and oncologic outcomes.

EVIDENCE ACQUISITION

This meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A literature search using the electronic databases (MEDLINE, Web of Science, Cochrane Library, and Scopus) included randomized controlled trials comparing the clinical safety and oncologic outcomes of GnRH agonists and antagonists. The endpoints of interest were the following: (1) treatment-related adverse effects (AEs), (2) prostate-specific antigen (PSA) progression, and (3) overall mortality. The relative risk (RR) was used as the summary statistic, and results were reported with 95% confidence intervals (CIs).

EVIDENCE SYNTHESIS

Eight clinical trials (20 published studies) comprising 2632 men met our inclusion criteria; of them, 1646 received GnRH antagonist and 986 had GnRH agonist. Treatment-emerging AEs occurred in 73% patients in the GnRH antagonist group and 68% in the GnRH agonist group (RR: 1.10, 95% CI: 1.04-1.15). Serious AEs occurred in 9.8% of the GnRH antagonist and 11% of the GnRH agonist group (RR: 0.92, 95% CI: 0.73-1.17). Antagonists were associated with higher injection site reaction rates (38%) than agonists (4.8%). GnRH antagonist was associated with fewer cardiovascular events (RR: 0.52, 95% CI: 0.34-0.80). There was no significant difference in PSA progression, but GnRH antagonist was associated with lower overall mortality rates than GnRH agonists (RR: 0.48, 95% CI: 0.26-0.90, p =  0.02).

CONCLUSIONS

Existing data indicate that GnRH antagonist use is associated with significantly lower overall mortality and cardiovascular events as compared with agonists. These findings should be interpreted with caution owing to the short follow-up duration and assessment of cardiovascular events as secondary endpoints in the included trials. Further studies are needed to validate or refute these observations. Injection site reactions were significantly higher in the GnRH antagonist group.

PATIENT SUMMARY

Gonadotropin-releasing hormone (GnRH) antagonist is associated with lower death rates and cardiovascular events than GnRH agonists, based on the data from trials with short follow-up duration. GnRH agonists are associated with lower adverse events, such as decreased libido, hot flushes, erectile dysfunction, back pain, weight gain, constipation, and injection site reactions. There were no significant differences in prostate-specific antigen progression or fatigue.

Oral Relugolix for Androgen-Deprivation Therapy in Advanced Prostate Cancer

BACKGROUND

Injectable luteinizing hormone-releasing hormone agonists (e.g., leuprolide) are the standard agents for achieving androgen deprivation for prostate cancer despite the initial testosterone surge and delay in therapeutic effect. The efficacy and safety of relugolix, an oral gonadotropin-releasing hormone antagonist, as compared with those of leuprolide are not known.

METHODS

In this phase 3 trial, we randomly assigned patients with advanced prostate cancer, in a 2:1 ratio, to receive relugolix (120 mg orally once daily) or leuprolide (injections every 3 months) for 48 weeks. The primary end point was sustained testosterone suppression to castrate levels (<50 ng per deciliter) through 48 weeks. Secondary end points included noninferiority with respect to the primary end point, castrate levels of testosterone on day 4, and profound castrate levels (<20 ng per deciliter) on day 15. Testosterone recovery was evaluated in a subgroup of patients.

RESULTS

A total of 622 patients received relugolix and 308 received leuprolide. Of men who received relugolix, 96.7% (95% confidence interval [CI], 94.9 to 97.9) maintained castration through 48 weeks, as compared with 88.8% (95% CI, 84.6 to 91.8) of men receiving leuprolide. The difference of 7.9 percentage points (95% CI, 4.1 to 11.8) showed noninferiority and superiority of relugolix (P<0.001 for superiority). All other key secondary end points showed superiority of relugolix over leuprolide (P<0.001). The percentage of patients with castrate levels of testosterone on day 4 was 56.0% with relugolix and 0% with leuprolide. In the subgroup of 184 patients followed for testosterone recovery, the mean testosterone levels 90 days after treatment discontinuation were 288.4 ng per deciliter in the relugolix group and 58.6 ng per deciliter in the leuprolide group. Among all the patients, the incidence of major adverse cardiovascular events was 2.9% in the relugolix group and 6.2% in the leuprolide group (hazard ratio, 0.46; 95% CI, 0.24 to 0.88).

CONCLUSIONS

In this trial involving men with advanced prostate cancer, relugolix achieved rapid, sustained suppression of testosterone levels that was superior to that with leuprolide, with a 54% lower risk of major adverse cardiovascular events. (Funded by Myovant Sciences; HERO ClinicalTrials.gov number, NCT03085095.).

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.

Phase I trial of TAK-385 in hormone treatment-naïve Japanese patients with nonmetastatic prostate cancer

This open‐label, phase I dose‐finding study evaluated the gonadotropin‐releasing hormone antagonist, TAK‐385, in Japanese patients with nonmetastatic prostate cancer. In a two‐part design, patients received daily oral TAK‐385 at doses of 320 (loading, day 1)/80 (maintenance, day 2 and thereafter), 320/120, 320/160, or 360/120 mg for 28 days in a dose‐escalation phase (part A, n = 13), and at 320/80 or 320/120 mg for up to 96 weeks in a randomized expansion phase (part B, n = 30). Primary endpoint in both parts was safety, including dose‐limiting toxicity in part A. Secondary endpoints included pharmacokinetics, pharmacodynamics, and prostate‐specific antigen concentration. Ten (77%) patients in part A and all patients in part B experienced an adverse event; hot flush (part A, n = 4; part B, n = 15), viral upper respiratory tract infection (part A, n = 1; part B, n = 10), and diarrhea (part B, n = 8) were most frequent. No dose‐limiting toxicities were observed (part A). In 12 evaluable patients (part A), TAK‐385 was rapidly absorbed after a single loading dose; on day 28 (maintenance dose), median steady‐state T_max was ~1‐2 hours and mean t_1/2z was 67‐79 hours. All doses rapidly reduced testosterone concentrations to castration levels within 1 week. Durable reductions in prostate‐specific antigen of >90% from baseline were observed through 96 weeks. TAK‐385 appeared tolerable and resulted in sustained reductions in testosterone to castration levels at all doses. The lowest loading/maintenance dose required for a clinical effect was 320/80 mg.

http://ClinicalTrials.gov: NCT02141659.

Abiraterone acetate in combination with prednisone in the treatment of metastatic hormone-sensitive prostate cancer: clinical evidence and experience

More than a million men worldwide are diagnosed with prostate cancer every year. After androgen deprivation therapy (ADT), chemotherapy has been the only subsequent intervention to improve survival in the metastatic setting but has limitations for patients who may not tolerate its toxicity profile or are not candidates on the basis of comorbidities. Novel anti-androgens such as abiraterone acetate have shown promise for such patients. This review draws on clinical evidence and experience to identify abiraterone as a well-tolerated, effective alternative to docetaxel. In the castration-resistant setting, studies demonstrated a survival benefit over placebo, prompting further trials in the hormone-naïve population. More recently the STAMPEDE and LATITUDE studies suggest abiraterone has comparable survival outcomes to docetaxel in the castration-sensitive setting, with evidence in favour of its quality of life profile. Available comparisons with docetaxel are limited, but those available suggest they have comparable efficacy. However, the significant cost compared with docetaxel is a major barrier in resource-rationed healthcare settings. Overall, abiraterone is an effective alternative to chemotherapy for men with castration-sensitive prostate cancer, but this should be balanced with the significantly greater cost.

Varicocele repair in patients prepared for intracytoplasmic sperm injection: To do or not to do?

PURPOSE

This study sought to evaluate the impact of varicocele repair on intracytoplasmic sperm injection outcomes.

PATIENTS AND METHODS

A prospective comparative study was conducted at the Assisted Reproduction Unit, International Islamic Center for Population Studies and Researches, Al-Azhar University. This study included 100 non-azoospermic infertile men with a history of varicocele who were scheduled for intracytoplasmic sperm injection, half of them had already undergone prior subinguinal varicocelectomy at least 12 months prior to ICSI without clinically evident recurrence (treated group 1), and the other half has any grade of an unrepaired clinical varicocele (untreated group 2) at sperm injection. All cases were clinically evaluated and eligible for analysis by using inclusion and exclusion criteria. ICSI outcomes compared between the two groups, including fertilisation rate, embryo development rate and pregnancy outcome.

RESULTS

Our study did not show any significant difference between treated and untreated groups regarding the mean values of fertilisation (0.7759 ± 0.2708 vs. 0.7119 ± 0.3057, p = 0.2708), embryo development (0.7759 ± 0.2708 vs. 0.6991 ± 0.3211, p = 0.1990) or different embryo grades. There was no statistically significant difference between groups regarding pregnancy occurrence rates (p = 0.0928).

CONCLUSION

Infertile men scheduled for ICSI do not seem to benefit from varicocele repair as regard to the outcomes of ICSI.

PKM2 under hypoxic environment causes resistance to mTOR inhibitor in human castration resistant prostate cancer

The aim of this study was to explore the efficacy of mTOR inhibitor for castration-resistant prostate cancer (CRPC) under hypoxia. Although under normoxia C4-2AT6, it is a CRPC cell line, expressed elevated pAkt, pS6 and Pyruvate kinase M2 (PKM2) accompanied by elevated HIF-1a expression, 5% hypoxic condition further induced expression of these proteins. These results indicate hypoxic environment elevated PI3K/Akt/mTOR pathway in aggressive prostate cancer. However, C4-2AT6 cells treated with mTOR inhibitor under hypoxia less decreased compared to cells treated with the same dose drugs under normoxia. Western blot analysis showed mTOR inhibitor: RAD001 not only inhibited pS6, but also increased the expression of PKM2 in a dose and time dependent manner. Pyruvate kinase acts on glycolysis. PKM2, which is frequently express in tumor cells, is one isoform of pyruvate kinase. PKM2 is reported to act as a transcription factor. In the present study overexpression of PKM2 in C4-2AT6 induced resistance to RAD001 under normoxia. To evaluate the therapeutic effect of targeting PKM2, we inhibited PKM2 in C4-2AT6 under hypoxia using si-PKM2. The number of C4-2AT6 under chronic hypoxia exposed to siPKM2 significantly decreased compared to intact C4-2AT6 under chronic hypoxia. Furthermore, si-PKM2 improved resistance to mTOR inhibitor in C4-2AT6. When examined using clinical samples, high PKM2 expression was correlated with a high Gleason score and poor PSA free survival. These results suggested that up-regulation of PKM2 is one possibility of resistance to mTOR inhibitor in CRPC. And it is possible that PKM2 is a useful therapeutic target of CRPC.

Efficacy and safety of 3-month dosing regimen of degarelix in Japanese subjects with prostate cancer: A phase III study

Non‐inferiority in the cumulative castration rate of the 3‐month formulation of degarelix compared with the 3‐month formulation of goserelin was evaluated in subjects with prostate cancer. A phase III, open‐label, parallel‐arm study was carried out. An initial dose of 240 mg degarelix or 3.6 mg goserelin was given s.c.; after day 28, a maintenance dose of 480 mg degarelix or 10.8 mg goserelin was given once every 84 days. Non‐inferiority in castration rate and safety of degarelix to goserelin were evaluated. The primary end‐point was the cumulative castration rate from day 28 to day 364 and the non‐inferiority margin was set to be 10%. A total of 234 subjects with prostate cancer were randomized to the degarelix group (n = 117) and the goserelin group (n = 117). The cumulative castration rate was 95.1% in the degarelix group and 100.0% in the goserelin group. As there were no events in the goserelin group, an additional analysis was carried out using 95% confidence intervals of the difference in the proportion of subjects with castration. Analyses indicated the non‐inferiority of the 3‐month formulation of degarelix to goserelin. Degarelix showed more rapid decreases in testosterone, luteinizing hormone, follicle stimulating hormone, and prostate‐specific antigen levels compared with goserelin. The most common adverse events in the degarelix group were injection site reactions. Non‐inferiority of the 3‐month formulation of degarelix to goserelin was shown for testosterone suppression. The 3‐month formulation of degarelix was also found to be tolerated as an androgen deprivation therapy for patients with prostate cancer. This trial was registered with ClinicalTrials.gov (identifier NCT01964170).

Androgen Deprivation Therapy Potentiates the Efficacy of Vascular Targeted Photodynamic Therapy of Prostate Cancer Xenografts

Purpose: WST11 vascular targeted photodynamic therapy (VTP) is a local ablation approach relying upon rapid, free radical-mediated destruction of tumor vasculature. A phase III trial showed that VTP significantly reduced disease progression when compared with active surveillance in patients with low-risk prostate cancer. The aim of this study was to identify a druggable pathway that could be combined with VTP to improve its efficacy and applicability to higher risk prostate cancer tumors.Experimental Design: Transcriptome analysis of VTP-treated tumors (LNCaP-AR xenografts) was used to identify a candidate pathway for combination therapy. The efficacy of the combination therapy was assessed in mice bearing LNCaP-AR or VCaP tumors.Results: Gene set enrichment analysis identifies the enrichment of androgen-responsive gene sets within hours after VTP treatment, suggesting that the androgen receptor (AR) may be a viable target in combination with VTP. We tested this hypothesis in mice bearing LNCaP-AR xenograft tumors by using androgen deprivation therapy (ADT), degarelix, in combination with VTP. Compared with either ADT or VTP alone, a single dose of degarelix in concert with VTP significantly inhibited tumor growth. A sharp decline in serum prostate-specific antigen (PSA) confirmed AR inhibition in this group. Tumors treated by VTP and degarelix displayed intense terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining 7 days after treatment, supporting an increased apoptotic frequency underlying the effect on tumor inhibition.Conclusions: Improvement of local tumor control following androgen deprivation combined with VTP provides the rationale and preliminary protocol parameters for clinical trials in patients presented with locally advanced prostate cancer. Clin Cancer Res; 24(10); 2408-16. ©2018 AACR.

Taking the first steps in establishing recommendations for testosterone monitoring in men with prostate cancer on androgen-deprivation therapy

The paper by Shayegan et al in this issue of CUAJ represents an important initial step in establishing recommendations for hormonal monitoring in men with prostate cancer on androgen-deprivation therapy (ADT). As with most subjects related to the actions of testosterone, the survey adds to the controversies, but also opens the opportunity to explore several of the concerns relevant to the hormonal management of prostate cancer.

Pharmacotherapeutic Targeting of G Protein-Coupled Receptors in Oncology: Examples of Approved Therapies and Emerging Concepts

G protein-coupled receptors (GPCRs) are involved in numerous physio-pathological processes, including the stimulation of cancer progression. In this regard, it should be mentioned that although GPCRs may represent major pharmaceutical targets, only a few drugs acting as GPCR inhibitors are currently used in anti-tumor therapies. For instance, certain pro-malignancy effects mediated by GPCRs are actually counteracted by the use of small molecules and peptides that function as receptor antagonists or inverse agonists. Recently, humanized monoclonal antibodies targeting GPCRs have also been developed. Here, we review the current GPCR-targeted therapies for cancer treatment, summarizing the clinical studies that led to their official approval. We provide a broad overview of the mechanisms of action of the available anti-cancer drugs targeting gonadotropin-releasing hormone, somatostatin, chemokine, and Smoothened receptors. In addition, we discuss the anti-tumor potential of novel non-approved molecules and antibodies able to target some of the aforementioned GPCRs in different experimental models and clinical trials. Likewise, we focus on the repurposing in cancer patients of non-oncological GPCR-based drugs, elucidating the rationale behind this approach and providing clinical evidence on their safety and efficacy.

Switching from an LHRH Antagonist to an LHRH Agonist: A Case Report of 10 Finnish Patients with Advanced Prostate Cancer

Introduction

Luteinizing hormone-releasing hormone (LHRH) analogues are widely used for the treatment of advanced hormone-dependent prostate cancer. However, there are currently no clinical guidelines for switching between LHRH analogues. It has been reported that there may be clinical benefits for patients switching between different formulations of LHRH agonists, as well as from an LHRH agonist to LHRH antagonist, but there are no published data on switching from an LHRH antagonist to an LHRH agonist. In this paper, we summarize the clinical notes of 10 patients with hormone-sensitive advanced prostate cancer who switched from an LHRH antagonist to an LHRH agonist.

Methods

Patients with T3N0M0–T4N1M1 prostate cancer experiencing injection site reactions, such as pain and swelling, with monthly degarelix (Firmagon^®) subcutaneous injections were switched to the 3-monthly leuprorelin acetate implant (Leuprorelin Sandoz^®) subcutaneous injections.

Results

Mean patient age was 75 years (SD 8.3; range 59–85) and Gleason scores ranged from 7 to 9. The mean [±standard deviation (SD)] duration of degarelix treatment was 5 ± 3.7 months (range 2–13). After switching, prostate serum antigen levels were comparable or reduced from those measured prior to switching, showing that efficacy was not compromised. Throughout the course of treatment, no patients reported injection site reactions. Patients reported increased satisfaction with the leuprorelin acetate implant versus degarelix, mainly because of a lack of injection site reactions and reduced frequency of injection.

Conclusion

This is the first report of the clinical experience and potential cost implications of switching from an LHRH antagonist to an LHRH agonist. These data are consistent with other experiences of switching between LHRH analogues in terms of efficacy, safety, and potential cost savings, and provide preliminary evidence that the switch from an LHRH antagonist to an agonist is safe and equally efficacious.

Maximal testosterone suppression in the management of recurrent and metastatic prostate cancer

INTRODUCTION

Testosterone suppression, or androgen-deprivation therapy (ADT), is an established treatment for recurrent and metastatic prostate cancer (PCa). Based on the accuracy and sensitivity of early assays (c. 1960-1970), the castrate testosterone level was set at ≤1.7 nmol/l. Improved sensitivity of testosterone assays shows that both surgical and medical castration can achieve levels <0.7 nmol/l. However, the clinical implications and importance of maximum testosterone suppression remains a subject of controversy. This evidence-based review assesses prospective and retrospective clinical data, linking maximum suppression of testosterone with improved outcomes from ADT.

METHODS

PubMed and conference proceedings were searched for studies assessing the impact of low testosterone on clinical outcomes from ADT. The key search terms included combinations of prostate cancer and testosterone, predictive/prognostic, and androgen deprivation. Results were limited to studies investigating the relationship between testosterone levels and clinical outcomes.

RESULTS

Both prospective and retrospective data support a relationship between testosterone levels below the historical standard of 1.7 nmol/l and improved outcomes. Eight studies showed significant improvements in survival-related outcomes, with the majority of data supporting a testosterone level cutoff of ≤0.7 nmol/l.

CONCLUSIONS

Tracking both testosterone and prostate-specific antigen (PSA) levels has significant clinical benefits, and the serum testosterone threshold of ≤0.7 nmol/l is a practical goal. The relative levels of testosterone and PSA may indicate continued hormone responsiveness or progression toward castration-resistant prostate cancer (CRPC) and should, therefore, inform treatment strategy. Standardization of assay methods and clinical coordination to facilitate widespread access to state-of the art laboratory equipment is necessary to ensure accurate decision-making.

Unusual side effect from a luteinizing hormone-releasing hormone agonist, leuprorelin, in the treatment of prostate cancer: a case report

Background

The treatment options for high-risk prostate cancer are either radical prostatectomy or radiotherapy/brachytherapy depending on the patients’ prognosis. In older men with multiple comorbidities, radiotherapy with androgen deprivation therapy is an attractive option. Common side effects of androgen deprivation therapy include hot flushes, tiredness, increased risk of fractures, increased risk of metabolic disorders, coronary heart disease, and psychological effects. This case highlights the potential side effect of lipodystrophy secondary to leuprolide acetate injections. To the best of our knowledge, this is the first reported case of such an instance.

Case presentation

In this case report, we describe a 70-year-old white man with prostate-specific antigen of 1.8 ng/mL, clinical stage T2bN0M0, Gleason 4+5=9 prostate cancer who developed an unusual side effect from leuprolide acetate as part of his androgen deprivation therapy. Approximately 2 months after the initial 3-monthly injection of leuprolide acetate (Eligard 22.5 mg) our patient developed abnormal lipid deposition particularly in his deltoid and abdominal region. His upper limb mobility gradually became compromised due to the size of these abnormal fat depositions. He had liposuction to correct this lipodystrophy and had a good functional outcome and cosmesis from the procedure.

Conclusions

To the best of our knowledge, this is the first reported case of lipodystrophy secondary to leuprolide acetate injections. Leuprolide acetate in commonly used as one of the gonadotrophin-releasing hormone agonists and thus we should be mindful of the potential effect of producing lipodystrophy, especially in patients with cirrhosis, and to watch for any signs and symptoms as appropriate. The implication of this potential side effect poses difficult management strategies for such patients, and second-line alternatives such as chemotherapy may need to be considered.

Characterization of Gonadotrope Secretoproteome Identifies Neurosecretory Protein VGF-derived Peptide Suppression of Follicle-stimulating Hormone Gene Expression

Reproductive function is controlled by the pulsatile release of hypothalamic gonadotropin-releasing hormone (GnRH), which regulates the expression of the gonadotropins luteinizing hormone and FSH in pituitary gonadotropes. Paradoxically, Fshb gene expression is maximally induced at lower frequency GnRH pulses, which provide a very low average concentration of GnRH stimulation. We studied the role of secreted factors in modulating gonadotropin gene expression. Inhibition of secretion specifically disrupted gonadotropin subunit gene regulation but left early gene induction intact. We characterized the gonadotrope secretoproteome and global mRNA expression at baseline and after Gα_s knockdown, which has been found to increase Fshb gene expression (1). We identified 1077 secreted proteins or peptides, 19 of which showed mRNA regulation by GnRH or/and Gα_s knockdown. Among several novel secreted factors implicated in Fshb gene regulation, we focused on the neurosecretory protein VGF. Vgf mRNA, whose gene has been implicated in fertility (2), exhibited high induction by GnRH and depended on Gα_s In contrast with Fshb induction, Vgf induction occurred preferentially at high GnRH pulse frequency. We hypothesized that a VGF-derived peptide might regulate Fshb gene induction. siRNA knockdown or extracellular immunoneutralization of VGF augmented Fshb mRNA induction by GnRH. GnRH stimulated the secretion of the VGF-derived peptide NERP1. NERP1 caused a concentration-dependent decrease in Fshb gene induction. These findings implicate a VGF-derived peptide in selective regulation of the Fshb gene. Our results support the concept that signaling specificity from the cell membrane GnRH receptor to the nuclear Fshb gene involves integration of intracellular signaling and exosignaling regulatory motifs.

A meta-analysis and systematic review of randomized controlled trials with degarelix versus gonadotropin-releasing hormone agonists for advanced prostate cancer

Our aim was to systematically evaluate the benefits of degarelix as antagonist versus agonists of gonadotropin-releasing hormones (GnRH) for the treatment of advanced prostate cancer (PC). This comparison was performed either in terms of biochemical or oncological or safety profiles. To this end we, carried out a systematic review and meta-analysis of the literature.We selected only studies directly and prospectively analyzing the two treatments in the same population (randomized phase III studies). We followed the Preferred Reporting Items for Systematic Reviews and meta-analyses process for reporting studies.After we eliminated studies according to the exclusion criteria, 9 publications were considered relevant to this review. These articles described 5 clinical trials that were eligible for inclusion. The follow-up duration in all trials did not exceed 364 days. This meta-analysis and review comprised a total of 1719 men, 1061 randomized to degarelix versus 658 to GnRH agonists treatment for advanced PC. Oncological results were evaluated only in 1 trial (CS21:408 cases) and they were not the primary endpoints of the study. Treatment emerging adverse events were reported in 61.4% and 58.8% of patients in the degarelix and GnRH agonists group, respectively (odds ratio, OR = 1.17; 95% confidence interval, 95% CI: 0.78-1.77, P > 0.1). Treatment related severe cardiovascular side effects were reported (trial CS21-30-35) in 1.6% and 3.6% of patients in the degarelix and GnRH agonists group, respectively (OR = 0.55, 95% CI: 0.26-1.14, P > 0.1).Our analysis evidences relevant limitations in particular for the comparative evaluation of the efficacy and the oncological results related to degarelix.