The efficacy and safety of degarelix, a GnRH antagonist: a 12-month, multicentre, randomized, maintenance dose-finding phase II study in Japanese patients with prostate cancer

Assessing the effects of prostate cancer therapies on cardiovascular health

Contemporary advances in prostate cancer treatments have markedly improved patient outcomes, yet concerns persist regarding the increased cardiovascular toxicity of prostate cancer treatments, which is multifaceted. Local therapies entail non-negligible cardiovascular risks. The effects of androgen deprivation therapy, which is pivotal in disease management, on cardiovascular health remains contentious, with gonadotropin-releasing hormone agonists and antagonists showing varying cardiovascular outcomes. Despite the ongoing controversy over the cardiovascular risks of gonadotropin-releasing hormone antagonists versus agonists, current evidence does not support favouring one over the other based solely on cardiovascular risk. Combination therapy with androgen receptor pathway inhibitors and androgen deprivation therapy shows additive cardiovascular risks, but robust comparative data are lacking. Chemotherapies such as docetaxel and cabazitaxel, along with emerging targeted therapies and radiopharmaceuticals, are associated with varied cardiovascular risks, necessitating personalized patient assessment. Clinicians should adhere to cardio-oncology guidelines when prescribing therapeutic agents, especially for patients with pre-existing cardiovascular conditions. Optimal monitoring and management strategies are essential to mitigate cardiovascular morbidity and mortality.

GnRH antagonist monotherapy versus a GnRH agonist plus bicalutamide for advanced hormone-sensitive prostate cancer; KYUCOG-1401

OBJECTIVES

To compare the effectiveness and safety of gonadotropin-releasing hormone (GnRH) antagonist monotherapy to combined androgen blockade (CAB) with a GnRH agonist and bicalutamide in patients with advanced hormone-sensitive prostate cancer (HSPC).

METHODS

The study was conducted as KYUCOG-1401 trial (UMIN000014243) and enrolled 200 patients who were randomly assigned to either group A (GnRH antagonist monotherapy followed by the addition of bicalutamide) or group B (CAB by a GnRH agonist and bicalutamide). The primary endpoint was PSA progression-free survival. The secondary endpoints were the time to CAB treatment failure, radiographic progression-free survival, overall survival, changes in serum parameters, including PSA, hormones, and bone and lipid metabolic markers, and adverse events.

RESULTS

PSA progression-free survival was significantly longer in group B (hazard ratio [HR], 95% confidence interval [CI]; 1.40, 1.01-1.95, p = 0.041). The time to CAB treatment failure was slightly longer in group A (HR, 95% CI; 0.80, 0.59-1.08, p = 0.146). No significant differences were observed in radiographic progression-free survival or overall survival. The percentage of patients with serum testosterone that did not reach the castration level was higher at 60 weeks (p = 0.046) in group A. No significant differences were noted in the serum levels of bone metabolic or lipid markers between the two groups. An injection site reaction was more frequent in group A.

CONCLUSIONS

The present results support the potential of CAB using a GnRH agonist and bicalutamide as a more effective treatment for advanced HSPC than GnRH antagonist monotherapy.

Degarelix for treating advanced hormone-sensitive prostate cancer

BACKGROUND

Degarelix is a gonadotropin-releasing hormone antagonist that leads to medical castration used to treat men with advanced or metastatic prostate cancer, or both. It is unclear how its effects compare to standard androgen suppression therapy.

OBJECTIVES

To assess the effects of degree compared with standard androgen suppression therapy for men with advanced hormone-sensitive prostate cancer.

SEARCH METHODS

We searched multiple databases (CENTRAL, MEDLINE, Embase, Scopus, Web of Science, LILACS until September 2020), trial registries (until October 2020), and conference proceedings (until December 2020). We identified other potentially eligible trials by reference checking, citation searching, and contacting study authors.

SELECTION CRITERIA

We included randomized controlled trials comparing degarelix with standard androgen suppression therapy for men with advanced prostate cancer.

DATA COLLECTION AND ANALYSIS

Three review authors independently classified studies and abstracted data from the included studies. The primary outcomes were overall survival and serious adverse events. Secondary outcomes were quality of life, cancer-specific survival, clinical progression, other adverse events, and biochemical progression. We used a random-effects model for meta-analyses and assessed the certainty of evidence for the main outcomes according to GRADE.

MAIN RESULTS

We included 11 studies with a follow-up of between three and 14 months. We also identified five ongoing trials. Primary outcomes Data to evaluate overall survival were not available.  Degarelix may result in little to no difference in serious adverse events compared to standard androgen suppression therapy (risk ratio (RR) 0.80, 95% confidence interval (CI) 0.62 to 1.05; low-certainty evidence; 2750 participants). Based on 114 serious adverse events in the standard androgen suppression group, this corresponds to 23 fewer serious adverse events per 1000 participants (43 fewer to 6 more). We downgraded the certainty of evidence for study limitations and imprecision. Secondary outcomes Degarelix likely results in little to no difference in quality of life assessed with a variety of validated questionnaires (standardized mean difference 0.06 higher, 95% CI 0.05 lower to 0.18 higher; moderate-certainty evidence; 2887 participants), with higher scores reflecting better quality of life. We downgraded the certainty of evidence for study limitations. Data to evaluate cancer-specific survival were not available. The effects of degarelix on cardiovascular events are very uncertain (RR 0.15, 95% CI 0.04 to 0.61; very low-certainty evidence; 80 participants). We downgraded the certainty of evidence for study limitations, imprecision, and indirectness as this trial was conducted in a unique group of high-risk participants with pre-existing cardiovascular morbidities. Degarelix likely results in an increase in injection site pain (RR 15.68, 95% CI 7.41 to 33.17; moderate-certainty evidence; 2670 participants). Based on 30 participants per 1000 with injection site pain with standard androgen suppression therapy, this corresponds to 440 more injection site pains per 1000 participants (192 more to 965 more). We downgraded the certainty of evidence for study limitations. We did not identify any relevant subgroup differences for different degarelix maintenance doses.

AUTHORS' CONCLUSIONS

We did not find trial evidence for overall survival or cancer-specific survival comparing degarelix to standard androgen suppression, but serious adverse events and quality of life may be similar between groups. The effects of degarelix on cardiovascular events are very uncertain as the only eligible study had limitations, was small with few events, and was conducted in a high-risk population. Degarelix likely results in an increase in injection site pain compared to standard androgen suppression therapy. Maximum follow-up of included studies was 14 months, which is short. There is a need for methodologically better designed and executed studies with long-term follow-up evaluating men with metastatic prostate cancer.

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

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

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).

Efficacy and safety of a 3-month dosing regimen of degarelix in Japanese patients with prostate cancer: a phase II maintenance-dose-finding study

Objective

To evaluate the efficacy and safety of degarelix 3-month depot in Japanese patients with prostate cancer.

Methods

In this Phase II, open-label, parallel-group study, 155 Japanese prostate cancer patients were randomized to treatment with degarelix administered subcutaneously at a maintenance dose of 360 or 480 mg every 84 days for 12 months, after receiving an initial dose of 240 mg. The primary endpoint was the cumulative probability of serum testosterone ≤0.5 ng/ml (Days 28–364). Secondary endpoints included percent change in serum prostate-specific antigen level and proportion of patients with prostate-specific antigen failure at Day 364. For safety, adverse events were evaluated.

Results

The cumulative probability of serum testosterone ≤0.5 ng/ml (Days 28–364) was 88.3% (95% confidence interval: 77.9–94.0%) and 97.2% (95% confidence interval: 89.4–99.3%) in the 360 and 480 mg groups, respectively. The median percent change in serum prostate-specific antigen level from baseline to Day 364 was −95.05% and −96.43% in the 360 and 480 mg groups, respectively; the proportion of patients with prostate-specific antigen failure was 2.7% and 1.3%. The most frequent adverse event was injection site reaction; however, this did not cause any patient to discontinue treatment.

Conclusions

The 3-month dosing regimen of degarelix 360/480 mg was effective and well tolerated for treatment of Japanese prostate cancer patients. The 480 mg group showed a higher cumulative castration rate than the 360 mg group; thus, 480 mg was considered to be the optimal clinical dosage for future Phase III trials.

A gonadotropin-releasing hormone antagonist reduces serum adrenal androgen levels in prostate cancer patients

Background

Adrenal androgens play an important role in the development of castration-resistant prostate cancer therapeutics. The effect of gonadotropin-releasing hormone (GnRH) antagonists on adrenal androgens has not been studied sufficiently. We measured testicular and adrenal androgen levels in patients treated with a GnRH antagonist.

Methods

This study included 47 patients with histologically proven prostate cancer. All of the patients were treated with the GnRH antagonist degarelix. The mean patient age was 73.6 years. Pre-treatment blood samples were collected from all of the patients, and post-treatment samples were taken at 1, 3, 6, and 12 months after starting treatment. Testosterone (T), dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), 17β-estradiol (E2), and androstenedione (A-dione) were measured by liquid chromatography-mass spectrometry. Dehydroepiandrosterone-sulfate (DHEA-S), luteinizing hormone, and follicle-stimulating hormone levels were measured by electro-chemiluminescence immunoassays.

Results

A significant reduction in T level (97.3% reduction) was observed in the patients 1 month after initiating treatment. In addition, levels of DHT, E2, DHEA-S, and A-dione decreased 1 month after initiating treatment (93.3, 84.9, 16.8, and 35.9% reduction, respectively). T, DHT, E2, DHEA-S, and A-dione levels remained significantly suppressed (97.1, 94.6, 85.3, 23.9, and 40.5% reduction, respectively) 12 months after initiating treatment. A significant decrease in DHEA level (15.4% reduction) was observed 12 months after initiating treatment.

Conclusions

Serum adrenal androgen levels decreased significantly in patients treated with a GnRH antagonist. Thus, long-term GnRH antagonist treatment may reduce serum adrenal androgen levels.

Discovery of LHRH and development of LHRH analogs for prostate cancer treatment

The discovery, isolation, elucidation of structure, synthesis, and initial testing of the neuropeptide hypothalamic luteinizing hormone-releasing hormone (LHRH), which regulates reproduction, is briefly described. The design, synthesis, and experimental and clinical testing of agonistic analogs of LHRH is extensively reviewed focusing on the development of new methods for the treatment of prostate cancer. Subsequent development of antagonistic analogs of LHRH is then faithfully recounted with special emphasis on therapy of prostate cancer and BPH. The concepts of targeted therapy to peptide receptors on tumors are re-examined and the development of the cytotoxic analogs of LHRH and their status is reviewed. The endeavor to develop better therapies for prostate cancer, based on LHRH analogs, guided much of our work.

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.

Efficacy of a neoadjuvant gonadotropin-releasing hormone antagonist plus low-dose estramustine phosphate in high-risk prostate cancer: a single-center study

PURPOSE

The optimal treatment for high-risk prostate cancer (Pca) remains to be established. We previously reported favorable biochemical recurrence-free survival (BRFS) for high-risk Pca patients treated with neoadjuvant therapy comprising a luteinizing hormone-releasing hormone agonist plus low-dose estramustine (LHRH + EMP) prior to radical prostatectomy (RP). In the present study, we evaluated the efficacy of neoadjuvant therapy comprising a gonadotropin-releasing hormone antagonist plus low-dose estramustine phosphate (GnRH + EMP) in patients with high-risk Pca.

METHODS

Between September 2005 and March 2016, we identified 406 high-risk Pca patients of whom 136 received neoadjuvant GnRH + EMP (GnRH group) and 270 received LHRH + EMP (LHRH group) before RP. We retrospectively evaluated the clinical and pathological covariates between the two groups. The endpoint was the rate of pathological T0 status.

RESULTS

The rates of pathological T0 status were 11.0 and 8.9% in the GnRH group and LHRH group, respectively (P = 0.490). The 2-year BRFS rates were 97.8% in the GnRH group and 87.8% in the LHRH group (P = 0.027).

CONCLUSION

Our findings suggest that neoadjuvant GnRH antagonist + EMP followed by RP may improve the pathological outcomes and reduce the risk of biochemical recurrence in patients with high-risk Pca. Further prospective studies to confirm these findings are warranted.

Efficacy, safety, and dose comparison of degarelix for the treatment of prostate cancer: A systematic review and meta-analysis

AIM: To conduct a systematic review and meta-analysis into the efficacy, safety, and dosage regimens of degarelix for treating prostate cancer (PCa).

METHODS: PubMed, EMBASE, the Cochrane Library, and Web of Science was systematically searched to identify randomized controlled trials (RCTs) comparing degarelix (240/80 mg vs 240/160 mg) to the gonadotropin-releasing hormone agonists, goserelin and leuprolide, for the treatment of PCa. Two independent reviewers screened putative studies, assessed the risk of bias, and then extracted pertinent data. Analyses were performed using Review Manager 5.2.

RESULTS: Seven papers from six RCTs, involving 1204 patients, were identified. The present meta-analysis showed that treatment with 240/160 mg degarelix is more effective and has fewer adverse events (AEs) relative to conventional 240/80 mg regimen. Degarelix significantly decreased International Prostate Symptom Scores [standardized mean differences (SMD) = -0.32, 95%CI: -0.51 to -0.12, P = 0.02] and caused fewer AEs (SMD = -0.28, 95%CI: -0.48 to -0.07, P = 0.008) than goserelin. Degarelix suppressed testosterone and prostate-specific antigen significantly faster than leuprolide.

CONCLUSION: Degarelix is a useful option in the treatment of advanced PCa. Degarelix 240/160 mg regimen was superior to a 240/80 mg regimen. More rigorously designed RCTs are urgently needed to confirm the efficacy of degarelix.

Cardiovascular risk after androgen deprivation therapy for prostate cancer: an Asian perspective

Androgen deprivation therapy (ADT) plays an important role in managing prostate cancer. However, ADT may result in major cardiovascular events and potentially lead to fatal consequences. Cardiovascular disease is the leading cause of mortality and it is a very important health condition to look into. Asians and Caucasians differ both physiologically and genetically, and they may have display different cardiovascular profiles. In this article, we reviewed the literature focusing on the cardiovascular risk after ADT for prostate cancer in the Asian population. We would discuss about the pathogenesis of ADT leading to cardiovascular events, summarize the findings concerning cardiac and stroke risks after ADT, compare between the different modalities of ADT and also provide genetic basics which are unique to Asians. We hope this article would provide more insights into the cardiovascular risk after ADT for prostate cancer in an Asian perspective.

Factors predicting progression to castrate-resistant prostate cancer in patients with advanced prostate cancer receiving long-term androgen-deprivation therapy

OBJECTIVES

To assess time to progression to castrate-resistant prostate cancer (CRPC) and factors influencing longer-term outcomes in patients receiving androgen-deprivation therapy (ADT) in an extension to the Triptocare study (NCT01020448). This is pertinent as the Triptocare study did not show that urinary prostate cancer antigen-3 (PCA3) score was a reliable marker of cancer stage in advanced prostate cancer and was not useful for assessing response 6 months after initiation of ADT with triptorelin 22.5 mg.

PATIENTS AND METHODS

An international, multicentre, non-interventional, observational, longitudinal, prospective study involving patients from the Triptocare study. CRPC status of patients was collected for up to 3 years from ADT initiation. Patient treatment and assessments were at the investigator's discretion. Co-primary endpoints were rate of CRPC at 3 years after initiating ADT and the median time to CRPC. An exploratory endpoint was the association of Triptocare baseline variables (including TMPRSS2-ERG and PCA3 scores) and PCA3 score at Triptocare last value available with CRPC onset.

RESULTS

Of the 325 patients in the Triptocare study safety population, 180 patients were enrolled in the Triptocare LT study (102 received continuous and 78 received intermittent ADT). CRPC rates at 3 years were 24/102 (23.5%) and 6/78 (7.7%) patients in the continuous and intermittent ADT groups, respectively. The median time to CRPC was not reached for either group. PCA3 score status at baseline was the only variable associated with a higher risk of progression to CRPC in both the intermittent and continuous ADT groups; compared with a baseline PCA3 score of ≥35, a PCA3 score below the level of quantification had a hazard ratio (HR) of 20.04 ([95% confidence interval (CI) 2.71-148.34] and a HR of 9.44 [95% CI 2.39-37.27], respectively). Baseline metastatic disease and testosterone level were additionally associated with progression to CRPC in the continuous ADT population (HR 5.20, 95% CI 1.68-16.06 and HR 0.995, 95% CI 0.991-0.999, respectively).

CONCLUSION

In men with locally advanced or metastatic prostate cancer, a PCA3 score of ≥35 at the time of initiating ADT may predict a lower risk of developing CRPC in the following 3 years.

Degarelix monotherapy compared with luteinizing hormone-releasing hormone (LHRH) agonists plus anti-androgen flare protection in advanced prostate cancer: an analysis of two randomized controlled trials

OBJECTIVES

The objective of this study was to assess differences in efficacy outcomes between luteinizing hormone-releasing hormone (LHRH) agonist plus antiandrogen (AA) flare protection and monotherapy with the gonadotrophin-releasing hormone antagonist degarelix in patients with prostate cancer.

METHODS

Data from 1455 patients were pooled from two prospective, phase III randomized 1-year clinical trials of degarelix versus LHRH agonist with or without AA. The AA bicalutamide was administered at the investigator's discretion. Adjusted hazard ratios (HRs) were calculated using a Cox proportional hazards regression model and a conditional logistic regression model was used for a case-control analysis of odds ratios (ORs).

RESULTS

Patients received degarelix monotherapy (n = 972) or LHRH agonist (n = 483) of whom 57 also received AA. Overall, prostate-specific antigen progression-free survival (PSA PFS) was improved with degarelix versus LHRH agonist + AA (Cox proportional hazards regression model-adjusted HR for PSA PFS failure was 0.56 [95% confidence interval (CI) 0.33-0.97, p = 0.038]). To compensate for a higher proportion of patients with metastases, Gleason score 7-10, and PSA >20 ng/ml in the LHRH agonist + AA group, a case-control analysis using a conditional logistic regression model was utilized. This resulted in an OR for PSA PFS of 0.42 (95% CI 0.20-0.89; p = 0.023) in the overall population, and 0.35 (95% CI 0.13-0.96; p = 0.042) in patients with PSA >50 ng/ml at baseline, when treated with degarelix versus LHRH agonists + AA. There were a small number of deaths, 1.9% with degarelix and 7% with LHRH agonists + AA (case-control analysis OR = 0.37; p = 0.085).

CONCLUSIONS

Degarelix monotherapy produced a more favorable effect on PSA PFS outcomes than a LHRH agonist + AA flare protection therapy in patients with prostate cancer when a case-control analysis was used to compensate for differences between treatment groups.

Degarelix therapy for prostate cancer in a real-world setting: experience from the German IQUO (Association for Uro-Oncological Quality Assurance) Firmagon® registry

Background

We investigated the use of the gonadotropin-releasing hormone (GnRH) antagonist degarelix in everyday clinical practice using registry data from uro-oncology practices in Germany.

Methods

Data were analysed retrospectively from the IQUO (Association for uro-oncological quality assurance) patient registry. Data were prospectively collected from all consecutive PCa patients treated with degarelix (n = 1010) in 138 uro-oncology practices in Germany between May 2009 and December 2013.

Results

Median overall survival had not yet been reached in the all-patient group or in subgroups who had or had not received prior hormonal therapy (HT). Cox regression analysis showed that patients who had received prior HT (n = 542) had a 58 % increased mortality risk (hazard ratio 1.58, 95 % CI 1.20–2.09) versus patients who had not (n = 468) (p = 0.001). Also, in patients who had received prior luteinizing hormone-releasing hormone (LHRH) analogue therapy (LHRH agonists or GnRH antagonists), median time to PSA progression was shorter (209 weeks) than in those who had not received prior LHRH analogues (n = 555; median PSA progression-free survival not yet reached). Degarelix was generally well tolerated.

Conclusions

Degarelix was effective and well tolerated in everyday clinical practice, confirming observations from clinical studies. Patients who received prior HT appeared to have a significantly higher mortality risk.

Efficacy and safety of leuprorelin acetate 6-month depot in prostate cancer patients: a Phase III, randomized, open-label, parallel-group, comparative study in Japan

Objective

Leuprorelin acetate (TAP-144-SR) is commonly used worldwide in prostate cancer patients. This study was conducted to assess the non-inferiority of a 6-month depot formulation of TAP-144-SR (TAP-144-SR [6M]) 22.5 mg to a 3-month depot formulation of TAP-144-SR (TAP-144-SR [3M]) 11.25 mg in prostate cancer patients in Japan.

Methods

This was a 48-week Phase III, open-label, parallel-group comparative study. TAP-144-SR (6M) 22.5 mg (6M group) and TAP-144-SR (3M) 11.25 mg (3M group) were administered to 81 and 79 subjects, respectively. The primary endpoint was the rate of serum testosterone suppression to the castrate level (≤100 ng/dl).

Results

Serum testosterone of all subjects excluding one subject in the 3M group was suppressed to the castrate level throughout 48 weeks. The estimated between-group difference (6M group − 3M group) in suppression rate was 1.3% (95% confidence interval: −3.4, 6.8), and its lower confidence interval was more than −10% of the pre-determined allowable limit value to judge the non-inferiority. The prostate-specific antigen concentrations were stable throughout the study in both groups. Progressive disease in the best overall response based on the Response Evaluation Criteria In Solid Tumors was 0.0% for the 6M group and 2.6% for the 3M group. Adverse events occurred in 92.6% in the 6M group and 89.9% in the 3M group. Adverse events leading to discontinuation were reported in 2.5% in the 6M group and 3.8% in the 3M group.

Conclusions

TAP-144-SR (6M) was not inferior to TAP-144-SR (3M) for the suppressive effect on serum testosterone level. TAP-144-SR (6M) was also as well tolerated as TAP-144-SR (3M).

Hormonal therapy in oncology: a primer for the radiologist

OBJECTIVE

The purpose of this article is to provide a comprehensive imaging review of the common hormonal therapies used in oncology and the side effects associated with them.

CONCLUSION

Commonly used hormones in oncology include corticosteroids, somatostatin analogues, progestins, gonadotropin-releasing hormone agonists and antagonists, antiandrogens, aromatase inhibitors, and selective estrogen receptor modulators. Familiarity with these hormones and their side effects can help radiologists to be vigilant for the side effects and complications of these agents.

Degarelix: a review of its use in patients with prostate cancer

Degarelix (Firmagon(®); Gonax(®)) is a gonadotropin-releasing hormone receptor antagonist that is approved for the treatment of advanced (hormone-dependent) prostate cancer in the US and EU and the treatment of prostate cancer in Japan. In a pivotal randomized, controlled, 12-month phase III study, degarelix (initial subcutaneous dose of 240 mg followed by monthly dosages of 80 mg) was noninferior to leuprolide (monthly intramuscular dosages of 7.5 mg) in patients with prostate cancer of any stage for which endocrine treatment was indicated (except neoadjuvant hormonal therapy) with regard to suppression of testosterone to castration levels (i.e. ≤0.5 ng/mL). Suppression of testosterone and prostate-specific antigen (PSA) levels was faster with degarelix than with leuprolide, and no testosterone surges or microsurges were seen in degarelix recipients. Suppression of testosterone and PSA levels was maintained for the 12-month study duration and continued for up to 5 years in an extension to the main trial (including in patients switching from leuprolide to degarelix in the extension). The drug was generally well tolerated, with most adverse events being mild to moderate in severity. Injection-site reactions and events reflecting the expected effects of testosterone suppression (e.g. hot flushes, weight increase) were the most common treatment-emergent adverse events. Thus, degarelix is a useful option for the treatment of prostate cancer in patients for whom endocrine treatment is indicated.

Efficacy and safety of degarelix in Korean patients with prostate cancer requiring androgen deprivation therapy: Open-label multicenter phase III study

Purpose

To assess the noninferiority, efficacy, and safety of degarelix in achieving and maintaining testosterone at castrate levels (≤0.5 ng/mL) in Korean patients (CS42) versus non-Asian patients with prostate cancer (PCa).

Methods

A Phase III, open-label, multicenter, single-arm trial was conducted in Korean patients with PCa. Degarelix was administered at a starting dose of 240 mg followed by monthly (28-day intervals) maintenance doses of 80 mg (240/80 mg dose regimen) for 7 months. The results were compared with non-Asian patients receiving degarelix 240/80 mg in the CS21 study.

Results

The estimated difference in the cumulative probabilities of testosterone ≤0.5 ng/mL from Day 28 to Day 196 between the trials was −2.3% (96.7% in CS42 vs. 99.0% in CS21). The lower limit of the 95% confidence interval was −5.5%, i.e., above the predefined noninferiority limit of −10% and thus noninferiority was established. Decreases in serum testosterone, prostate-specific antigen, and luteinizing hormone over time were similar in CS42 and CS21. There were no clinically significant differences in incidence of treatment-emergent adverse events (72% in CS42 vs. 70% in CS21) and changes in clinical chemistry and hematology parameters between the two trials. The most common adverse event was injection-site reaction.

Conclusions

Overall, degarelix was effective and well tolerated in Korean patients. Testosterone suppression was noninferior to that in non-Asian patients and safety findings were as would be expected for elderly men with PCa undergoing androgen deprivation therapy.

Bench-to-bedside development of agonists and antagonists of luteinizing hormone-releasing hormone for treatment of advanced prostate cancer

BACKGROUND

Androgen deprivation therapy (ADT) has been the standard of care for treating patients with hormone-sensitive advanced prostate cancer (PCa) for 3 decades. The agonists of luteinizing hormone-releasing hormone (LHRH), also called gonadotropin-releasing hormone, are still the most frequently used form of medical ADT.

ADT AND LHRH ANALOGS

The application of agonists of LHRH has improved and modernized the treatment of advanced PCa; millions of patients have benefited from therapy with LHRH agonists as a preferred alternative to surgical castration, as the psychological effects and perpetuity of orchiectomy are undesirable for most men. Despite their efficacy, agonists of LHRH have several shortcomings, including initial surge in testosterone, producing exacerbation of clinical symptoms, and microsurges in testosterone that might occur after each administration. A new, alternate approach to ADT is emerging with the improvements in antagonists of LHRH. This class of LHRH analogues produces a direct and immediate blockade of pituitary LHRH receptors and leads to a more rapid suppression of testosterone without an initial surge or subsequent microsurges. Degarelix, a third-generation LHRH antagonist, is the only antagonist with a low histamine-releasing activity that is currently on the market for clinical use in advanced PCa with improved testosterone suppression, better control of follicle-stimulating hormone and prostate-specific antigen, and which offers a prolonged delay to progression and more favorable effects on serum alkaline phosphatase.

CONCLUSIONS

Although LHRH agonists are still the mainstay for treatment of advanced PCa, antagonists of LHRH offer an alternative as a pharmacological approach.

Evaluation of histopathological findings at the injection site following degarelix administration

PURPOSE

The aims of the present study were to investigate the incidence of injection site reactions (ISRs) following administration of 240 mg degarelix and identify the risk factors for ISRs.

METHODS

This study was conducted in 50 consecutive men treated with degarelix for the first time. ISRs after an initial degarelix dose of 240 mg (administered subcutaneously as two 3 ml subcutaneous injection) were evaluated using the five categories of the Common Terminology Criteria for Adverse Events Version 4 of the National Cancer Institute. We also assessed the differences in patient background between patients with and without an ISR.

RESULTS

The mean age of patients and prostate-specific antigen (PSA) level just before degarelix administration were 75.6 and 198.4 ng/ml, respectively. Hormonal therapy with degarelix was administered for the first time to 33 patients; 11 of the 50 patients were receiving an oral steroid, 6 for prostate cancer, 1 for hematological disease, and 4 for allergic conditions. ISRs were observed in 25 patients, and all of the ISRs were categorized as grade 1 or 2; however, 2 patients discontinued this procedure due to the ISR. Significant differences in the first experience with subcutaneous therapy (p = 0.007) and rate of combination with a steroid (p = 0.017) were observed between patients with and without ISRs.

CONCLUSION

The incidences of ISRs in patients receiving subcutaneous therapy for the first time and in patients also receiving an oral steroid were 64 and 18 %, respectively. Patients should be provided with information concerning the possible occurrence of ISR due to degarelix prior to the administration, particularly patients who are not receiving steroids and patients who have no experience with subcutaneous injections.

Androgen receptor antagonists for prostate cancer therapy

Androgen deprivation is the mainstay therapy for metastatic prostate cancer (PCa). Another way of suppressing androgen receptor (AR) signaling is via AR antagonists or antiandrogens. Despite being frequently prescribed in clinical practice, there is conflicting evidence concerning the role of AR antagonists in the management of PCa. In the castration-resistant settings of PCa, docetaxel has been the only treatment option for decades. With recent evidence that castration-resistant PCa is far from AR-independent, there has been an increasing interest in developing new AR antagonists. This review gives a concise overview of the clinically available antiandrogens and the experimental AR antagonists that tackle androgen action with a different approach.

Agonists of luteinizing hormone-releasing hormone in prostate cancer

INTRODUCTION

Androgen deprivation therapy (ADT) has been the first-line standard of care for treating patients with hormone-sensitive advanced prostate cancer (PCa) for many decades. The agonists of luteinizing hormone-releasing hormone (LHRH), also called gonadotropin-releasing hormone, are still the most frequently used form of medical ADT.

AREAS COVERED

This article reviews the available data and most recent information concerning the use of LHRH agonists in advanced PCa. This article also reviews the discovery and development of LHRH agonists and summarizes the clinical evidence for their efficacy in PCa.

EXPERT OPINION

The introduction and application of agonists of LHRH has modernized and improved the treatment of advanced PCa. The life-saving benefits of LHRH agonists are well established, yet underestimated. Despite their efficacy, agonists of LHRH have several disadvantages or drawbacks including disease flare. The approach to ADT has been recently further refined with the development of the LHRH antagonist degarelix. Degarelix, a highly clinically effective third-generation LHRH antagonist, is currently available in most countries for therapy of advanced PCa. This new drug offers attractive alternatives to LHRH agonists for treatment of advanced PCa. A therapy for castration-resistant PCa based on a targeted cytotoxic analog of LHRH, AEZS-108, is also emerging.

Serum testosterone levels after medical or surgical androgen deprivation: a comprehensive review of the literature

Androgens and the androgen receptor play a role in the progression of prostate cancer. Androgen deprivation therapy (ADT) is a mainstay in the treatment of metastatic prostate cancer. ADT is expected to reduce serum testosterone levels from a normal level of about 500 to 600 ng/dl (17.3-20.8 nmol) down to castration levels. Traditionally, castration was considered to be achieved if testosterone levels were lowered to a threshold of 50 ng/dl (1.73 nmol/l), a definition determined more by measurement methods derived from the use of old assay methods than by evidence. Serum testosterone levels in three-quarter patients after surgical castration drop to less than 20 ng/dl (0.69 nmol/l). Ineffective suppression of testosterone is currently poorly recognized and may possibly have an effect of prostate cancer mortality. Persistent levels of serum testosterone after castration are mainly derived from adrenal androgens. Furthermore, the arrival of new therapies targeting androgen synthesis and androgen receptor activity has renewed interest on serum testosterone. This review discusses the biosynthetic pathway for androgen synthesis in humans and provides a comprehensive review of serum testosterone levels after surgical or medical castration. This review assesses serum testosterone levels after surgical castration and different pharmacologic castration in patients with prostate cancer under ADT, and ineffective testosterone suppression. The author proposes methods to better lower serum testosterone levels during ADT.

An update on the use of degarelix in the treatment of advanced hormone-dependent prostate cancer

Androgen deprivation therapy remains the mainstay of medical treatment for advanced prostate cancer. Commonly, this is achieved with medical androgen deprivation rather than surgical intervention as the permanence and psychological effects of the latter are unacceptable for most patients. Degarelix is a third generation antagonist of luteinizing hormone-releasing hormone (LHRH, also termed gonadotropin-releasing hormone) for the first-line treatment of androgen-dependent advanced prostate cancer. Degarelix acts directly on the pituitary receptors for LHRH, blocking the action of endogenous LHRH. The use of degarelix eliminates the initial undesirable surge in gonadotropin and testosterone levels, which is produced by agonists of LHRH. Degarelix is the most comprehensively studied and widely available LHRH antagonist worldwide. Clinical trials have demonstrated that degarelix has a long-term efficacy similar to the LHRH agonist leuprolide in achieving testosterone suppression in patients with prostate cancer. Degarelix, however, produces a faster suppression of testosterone and prostate-specific antigen (PSA), with no testosterone surges or microsurges, and thus prevents the risk of clinical flare in advanced disease. Recent clinical trials demonstrated that treatment with degarelix results in improved disease control when compared with an LHRH agonist in terms of superior PSA progression-free survival, suggesting that degarelix likely delays progression to castration-resistant disease and has a more significant impact on bone serum alkaline phosphatase and follicle-stimulating hormone. Degarelix is usually well tolerated, with limited toxicity and no evidence of systemic allergic reactions in clinical studies. Degarelix thus represents an important addition to the hormonal armamentarium for therapy of advanced androgen-dependent prostate cancer.

Experience with degarelix in the treatment of prostate cancer

Degarelix is a gonadotrophin-releasing hormone (GnRH) antagonist for the first-line treatment of androgen-dependent advanced prostate cancer. It has a direct mechanism of action that blocks the action of GnRH on the pituitary with no initial surge in gonadotrophin or testosterone levels. Degarelix is the most extensively studied and widely available GnRH antagonist worldwide. Clinical studies have demonstrated similar efficacy to the GnRH agonist leuprolide in achieving testosterone suppression in patients with prostate cancer. However, degarelix produces a faster suppression of testosterone and prostate-specific antigen (PSA), with no testosterone surge or microsurges, thus preventing the risk of clinical flare in advanced disease. Clinical trials have demonstrated that degarelix can offer improved disease control when compared with a GnRH agonist in terms of superior PSA progression-free survival (suggesting that degarelix likely delays progression to castration-resistant disease), and a more significant impact on bone serum alkaline phosphatase and follicle-stimulating hormone. Degarelix is generally well tolerated, with no reports of systemic allergic reactions in any clinical studies. In conclusion, degarelix offers clinicians a rational first-line hormonal monotherapy option for the management of advanced prostate cancer.