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Testosterone Recovery for Relugolix Versus Leuprolide in Men with Advanced Prostate Cancer: Results from the Phase 3 HERO Study
This study's purpose was to confirm the observed underexpression of miRNA-410 in glioma tissues and several glioma cells by Quantitative RT-PCR. Our findings suggest that epigenetic alterations occurring at the promoter region of miR-410 may be responsible for the reduced expression of miR-410 in glioma. The occurrence of DNA methylation in the miR-410 promoter was verified to be more prevalent through glioma tissues contrasted to adjacent non-tumor brain tissues through the utilization of methylation-specific PCR and CpG bisulfite sequencing sites in the miR-410 promoter region. Accordantly, miR-410 expression in glioma cell lines was observed to be significantly lesser in comparison to that of the human fetal glial cell line. In addition, it was demonstrated through gain- and loss-of-function investigations that miR-410 exerts significant regulation over cell growth, cell cycle development, and glioma cell apoptosis. The findings of the Luciferase reporter assay and western blot analysis indicate that miR-410 has a direct effect on the 3’-UTR of signal transducer and activator of transcription 3 (STAT3), thereby inhibiting its expression within glioma cells. Besides, our clinical investigation indicates a negative association between miR-410 expression and STAT3 within the glioma tissues of humans. In aggregate, the data provided in this investigation indicates that miR-410 is subjected to underexpression via DNA methylation. Furthermore, it has been observed to perform its function as a tumor suppressor in glioma cells through direct targeting of STAT3. The previously mentioned results could potentially have significant implications for the advancement of a new therapeutic approach for treating glioma.
Background
External beam radiotherapy (EBRT) with neoadjuvant/adjuvant androgen deprivation therapy (ADT) is an established treatment option to prolong survival for patients with intermediate- and high-risk prostate cancer (PCa). Relugolix, an oral gonadotropin-releasing hormone (GnRH) receptor antagonist, was evaluated in this clinical setting in comparison with degarelix, an injectable GnRH antagonist.
Objective
To evaluate the safety and efficacy of relugolix to achieve and maintain castration.
Design, setting, and participants
A phase 2 open-label study was conducted in 103 intermediate-risk PCa patients undergoing primary EBRT and neoadjuvant/adjuvant ADT between June 2014 and December 2015.
Intervention
Patients randomly assigned (3:2) to 24-wk treatment with either daily oral relugolix or 4-wk subcutaneous depot degarelix (reference control).
Outcome measurements and statistical analysis
The primary endpoint was the rate of effective castration (testosterone <1.73 nmol/l) in relugolix patients between 4 and 24 wk of treatment. Secondary endpoints included rate of profound castration (testosterone <0.7 nmol/l), prostate-specific antigen (PSA) levels, prostate volume, quality of life (QoL) assessed using the Aging Males’ Symptoms scale, and the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life (30-item EORTC core questionnaire [EORTC QLQ-C30] and 25-item EORTC prostate cancer module [EORTC QLQ-PR25]) questionnaires, and safety. No formal statistical comparisons with degarelix were planned.
Results and limitations
Castration rates during treatment were 95% and 82% with relugolix and 89% and 68% with degarelix for 1.73 and 0.7 nmol/l thresholds, respectively. Median time to castration in the relugolix arm was 4 d. During treatment, PSA levels and prostate volumes were reduced in both groups. Three months after discontinuing treatment, 52% of men on relugolix and 16% on degarelix experienced testosterone recovery (statistical significance of differences not tested). Mean and median QoL scores improved following treatment discontinuation. The most common adverse event was hot flush (relugolix 57%; degarelix 61%). Lack of blinding was a potential limitation.
Conclusions
Relugolix achieved testosterone suppression to castrate levels within days and maintained it over 24 wk with a safety profile consistent with its mechanism of action.
Patient summary
Oral once-daily relugolix may be a novel oral alternative to injectable androgen deprivation therapies.
Introduction:
Androgen deprivation therapy (ADT) is frequently used in the treatment of prostate cancer worldwide. Variable testosterone (T) recovery profiles after ADT cessation have been cited.
Aim:
To evaluate T recovery after cessation of ADT.
Methods:
We reviewed our institutional prospectively maintained database of patients with prostate cancer who received ADT. Serum early morning total T (TT) levels, collected at baseline and periodically after ADT cessation, were analyzed. Patient age, baseline T level, duration of ADT, and presence of diabetes and sleep apnea were selected as potential predictors of T recovery. 3 metrics of T recovery after 24 months of ADT cessation were analyzed: return to non-castrate level (TT > 50 ng/dL), return to normal (T > 300 ng/dL), and return back to baseline level (BTB). Multivariable time-to-event analysis (Cox proportional hazards), χ2 test, logistic regression model, and Kaplan-Meier curve were performed to define impact of the above predictors on time and chance of T recovery.
Main outcome measures:
Time and chance of T recovery to non-castrate level (TT > 50 ng/dL), return to normal (T > 300 ng/dL), and return BTB.
Results:
307 men with a mean age of 65 ± 8 years were included. Mean duration of ADT was 17 ± 25 months, and median follow-up was 31 ± 35 months. Mean TT values were 379 ng/dL at baseline and 321 ng/dL at >24 months. At 24 months after cessation of ADT, 8% of men remained at castrate level, 76% returned to TT >300 ng/dL, and 51% had returned BTB. Lower baseline T levels (TT < 400 ng/dL) and ADT duration >6 months were associated with a lower likelihood of recovery to normal TT at 24 months. Age >65 years and receiving ADT for >6 months were significantly associated with a slower T recovery.
Clinical implications:
T recovery after ADT is not certain and may take longer than expected. Considering the range of side effects of low T, we believe that these findings must be discussed with patients before initiating such therapies.
Strengths & limitations:
Our strengths consisted of a relatively large database, long follow-up, and clinically meaningful endpoints. Limitations included the retrospective design of the study.
Conclusion:
T recovery rates after ADT cessation vary according to patient age, ADT duration, and baseline T levels. Approximately one-quarter of patients failed to normalize their TT level, and one-tenth of men remained at castrate levels 24 months after ADT cessation. Nascimento B, Miranda EP, Jenkins LC, et al. Testosterone Recovery Profiles After Cessation of Androgen Deprivation Therapy for Prostate Cancer. J Sex Med 2019;16:872-879.
Recently, the standard of care for metastatic Castration Resistant Prostate Cancer (mCRPC) has changed considerably. Persistent androgen receptor (AR) signaling has been identified as a target for novel therapies and reengages the fact that AR continues to be the primary target responsible for metastatic prostate cancer. Androgen receptor gene amplification and over expression have been found to result in a higher concentration of androgen receptors on tumor cells, making them extremely sensitive to low levels of circulating androgens. Additionally, prostate cancer cells are able to maintain dihydrotestosterone (DHT) concentration in excess of serum concentrations to support tumor growth. For many years ketoconazole was the only CYP17 inhibitor that was used to treat mCRPC. However, significant toxicities limit its use. Newly approved chemotherapeutic agents such as Abiraterone (an oral selective inhibitor of CYP17A), which blocks androgen biosynthesis both within and outside the prostate cancer cells), and enzalutamide (blocks AR signaling) have improved overall survival. There are also ongoing phase III trials for Orteronel (TAK- 700), ARN- 509 and Galeterone (TOK-001), which targets androgen signaling. In this review, we will present the rationale for the newly approved hormonal treatments, their indications and complications, and we will discuss ongoing trials that are being done to improve the efficacy of the approved agents. Finally, we will talk about the potential upcoming hormonal treatments for mCRPC.
Intermittent androgen deprivation for prostate-specific antigen (PSA) elevation after radiotherapy may improve quality of life and delay hormone resistance. We assessed overall survival with intermittent versus continuous androgen deprivation in a noninferiority randomized trial.
We enrolled patients with a PSA level greater than 3 ng per milliliter more than 1 year after primary or salvage radiotherapy for localized prostate cancer. Intermittent treatment was provided in 8-month cycles, with nontreatment periods determined according to the PSA level. The primary end point was overall survival. Secondary end points included quality of life, time to castration-resistant disease, and duration of nontreatment intervals.
Of 1386 enrolled patients, 690 were randomly assigned to intermittent therapy and 696 to continuous therapy. Median follow-up was 6.9 years. There were no significant between-group differences in adverse events. In the intermittent-therapy group, full testosterone recovery occurred in 35% of patients, and testosterone recovery to the trial-entry threshold occurred in 79%. Intermittent therapy provided potential benefits with respect to physical function, fatigue, urinary problems, hot flashes, libido, and erectile function. There were 268 deaths in the intermittent-therapy group and 256 in the continuous-therapy group. Median overall survival was 8.8 years in the intermittent-therapy group versus 9.1 years in the continuous-therapy group (hazard ratio for death, 1.02; 95% confidence interval, 0.86 to 1.21). The estimated 7-year cumulative rates of disease-related death were 18% and 15% in the two groups, respectively (P=0.24).
Intermittent androgen deprivation was noninferior to continuous therapy with respect to overall survival. Some quality-of-life factors improved with intermittent therapy. (Funded by the Canadian Cancer Society Research Institute and others; ClinicalTrials.gov number, NCT00003653.).
Androgen deprivation therapy (ADT) is first-line treatment for metastatic prostate cancer (PCa). Gonadotrophin-releasing hormone (GnRH) agonists are the most commonly used ADT but have several theoretical physiologic disadvantages (e.g. initial testosterone surge, potential microsurges upon repeat administration). Testosterone surge delays the intended serologic endpoint of testosterone suppression and may exacerbate clinical symptoms. GnRH antagonists were developed with a view toward overcoming these potential adverse physiologic events. This review evaluates GnRH agonists and antagonists, assessing the potential future role of antagonists in PCa and strategies to minimize ADT adverse events (AEs). Evidence was identified via PubMed search (by GnRH agent and other ADT-related terms), from review article bibliographies, and authors' therapy area knowledge, with articles included by author consensus. Degarelix shows similar efficacy to a GnRH agonist in achieving and maintaining castration, with faster onset and without testosterone surge/microsurges. Phase III data showed that, in the first treatment year, degarelix displayed a lower risk of PSA failure or death (composite endpoint), lower levels of the bone marker serum alkaline phosphatase (in baseline metastatic disease), and fewer musculoskeletal AEs than the agonist leuprolide. Also, crossing over from leuprolide to degarelix after 1 year reduced the risk of PSA failure or death. ADT displays an AE spectrum which can impact quality of life as well as causing significant morbidities. Strategies to improve ADT tolerability have become increasingly important including: a holistic management approach, improved diet and exercise, more specific monitoring to detect and prevent testosterone depletion toxicities, and intermittent ADT allowing hormonal recovery between treatment periods. Clinical studies suggest possible benefits of GnRH antagonists over agonists based on different mechanisms of action. GnRH antagonists should now be considered as an alternative first-line ADT option in advanced PCa. Intermittent ADT and a holistic treatment approach are promising strategies to improve ADT tolerability.Prostate Cancer and Prostatic Diseases advance online publication, 3 July 2012; doi:10.1038/pcan.2012.25.
Study Type – Therapy (case series)
Level of Evidence 4
What's known on the subject? and What does the study add?
Erectile dysfunction is a recognized complication of radical prostatectomy. Androgen deprivation therapy adversely impacts sexual function.
Our study shows that the preoperative use of androgen deprivation therapy significantly reduces erectile function recovery after radical prostatectomy. The underneath pathophysiological mechanisms for this to occur are reviewed.
Androgen deprivation therapy (ADT) is the main treatment approach in advanced prostate cancer and in recent years has primarily involved the use of gonadotropin-releasing hormone (GnRH) agonists. However, despite their efficacy, GnRH agonists have several drawbacks associated with their mode of action. These include an initial testosterone surge and testosterone microsurges on repeat administration. GnRH antagonists provide an alternative approach to ADT with a more direct mode of action that involves immediate blockade of GnRH receptors. Antagonists produce a more rapid suppression of testosterone (and prostate-specific antigen [PSA]) without a testosterone surge or microsurges and appear to offer an effective and well tolerated option for the hormonal treatment of prostate cancer. Comparisons with GnRH agonists have shown GnRH antagonists to be at least as effective in achieving and maintaining castrate testosterone levels in patients with prostate cancer. Furthermore, with antagonists, the lack of an initial testosterone surge (which may cause clinical flare) may allow more rapid relief of symptoms related to prostate cancer, avoid the need for concomitant antiandrogens to prevent clinical flare (so avoiding any antiandrogen-associated adverse events) and allow GnRH antagonist use in patients with high tumour burden and/or acute problems such as spinal cord compression. Although several antagonists have been investigated, only degarelix and abarelix are currently available for clinical use in prostate cancer. Currently, degarelix is the most extensively studied and widely available agent in this class. Degarelix is one of a newer generation of antagonists which, in a comprehensive and ongoing clinical development programme, has been shown to provide rapid, profound and sustained testosterone suppression without the systemic allergic reactions associated with earlier antagonists. This review examines the currently available data on GnRH antagonists in prostate cancer.
PURPOSE
Update all preceding ASCO guidelines on initial hormonal management of noncastrate advanced, recurrent, or metastatic prostate cancer.
METHODS
The Expert Panel based recommendations on a systematic literature review. Recommendations were approved by the Expert Panel and the ASCO Clinical Practice Guidelines Committee.
RESULTS
Four clinical practice guidelines, one clinical practice guidelines endorsement, 19 systematic reviews with or without meta-analyses, 47 phase III randomized controlled trials, nine cohort studies, and two review papers informed the guideline update.
RECOMMENDATIONS
Docetaxel, abiraterone, enzalutamide, or apalutamide, each when administered with androgen deprivation therapy (ADT), represent four separate standards of care for noncastrate metastatic prostate cancer. Currently, the use of any of these agents in any particular combination or series cannot be recommended. ADT plus docetaxel, abiraterone, enzalutamide, or apalutamide should be offered to men with metastatic noncastrate prostate cancer, including those who received prior therapies, but have not yet progressed. The combination of ADT plus abiraterone and prednisolone should be considered for men with noncastrate locally advanced nonmetastatic prostate cancer who have undergone radiotherapy, rather than castration monotherapy. Immediate ADT may be offered to men who initially present with noncastrate locally advanced nonmetastatic disease who have not undergone previous local treatment and are unwilling or unable to undergo radiotherapy. Intermittent ADT may be offered to men with high-risk biochemically recurrent nonmetastatic prostate cancer. Active surveillance may be offered to men with low-risk biochemically recurrent nonmetastatic prostate cancer. The panel does not support use of either micronized abiraterone acetate or the 250 mg dose of abiraterone with a low-fat breakfast in the noncastrate setting at this time. Additional information is available at www.asco.org/genitourinary-cancer-guidelines .
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.)
200 Background: Gonadotropin-releasing hormone (GnRH) antagonists achieve rapid decrease in testosterone (T) without transient T surge seen with GnRH agonists and thus may avoid clinical flare symptomatology. TAK-385 is an investigational, oral, non-peptide GnRH antagonist highly selective for the human GnRH receptor (IC50 0.12 nM). We report IA2 results from a phase 2, randomized, open label, parallel group study of TAK-385 in pts with advanced prostate cancer (NCT02083185). Methods: Pts aged ≥ 18 yrs with histologically confirmed prostate cancer, baseline T > 150 ng/dL and prostate-specific antigen (PSA) > 2 ng/mL, who were candidates for first-line androgen deprivation therapy, were randomized to receive oral TAK-385, 80 or 120 mg, once daily (QD) or leuprorelin (LEU) 22.5 mg subcutaneously every 12 wks, for 48 wks. The primary endpoint was effective castration rate of TAK-385 (T < 50 ng/dL) from wk 5–24. Secondary endpoints included: safety, pharmacokinetics (PK), and PSA. Results: At data cut-off, 75...
Objective:
The aim of this study was to evaluate hormonal recovery after cessation of androgen deprivation therapy (ADT) in a group of elderly prostate cancer patients.
Materials and methods:
Forty patients with locally advanced or metastatic prostate cancer, with a mean age of 71.5 years [95% confidence interval (CI) 69.1-73.9], were treated with ADT for a mean duration of 74.6 months (95% CI 59.7-89.5 months). Mean follow-up time after ADT cessation was 36.5 months (95% CI 30.6-42.3 months). Serum testosterone and luteinizing hormone (LH) were determined at 6 month intervals after ADT cessation.
Results:
After 18 months of follow-up, all patients had recovered normal LH levels, while 38% of patients still presented castration levels of testosterone (< 50 ng/dl). A multivariate analysis was performed to find factors related to testosterone recovery (testosterone >50 ng/dl). Neither age at start of ADT nor clinical stage reached statistical significance. Only time under ADT was correlated with testosterone recovery (p = .031). Kaplan-Meier curves were obtained. Mean time for testosterone recovery was 14.5 months (95% CI 6.5-22.6 months) in patients treated with ADT for less than 60 months compared to 29.3 months (95% CI 19.6-39.1 months) in patients treated with ADT for more than 60 months (log-rank p = .029).
Conclusions:
Age did not correlate with testosterone recovery in a group of elderly prostate cancer patients in whom ADT was stopped. Testosterone recovery after ADT cessation was significantly correlated with time under ADT treatment. Significant implications related to economic aspects of the dosage schedule may be considered.
Context:
TAK-385 is a highly-selective, oral, non-peptide gonadotropin-releasing hormone antagonist being investigated as a possible prostate cancer treatment.
Objective:
Evaluate safety, tolerability, pharmacokinetics, and pharmacodynamics of TAK-385 on luteinizing hormone and testosterone.
Design, setting, and participants:
A three-part, randomized, double-blind, placebo-controlled, phase 1 dose-escalation study in 176 healthy male UK volunteers.
Interventions:
Part 1, single doses of TAK-385 (0 [placebo], 80, 120, 180, or 360 mg); Part 2, 14-day TAK-385 (40, 80, or 180 mg) daily; Part 3, 28-day TAK-385 or placebo (40 [with loading dose], 60, 80, or 160 mg) daily. Parts 2 and 3 included men aged 40-70 years.
Main outcome measures:
Plasma concentrations of TAK-385, luteinizing hormone, and testosterone.
Results:
Oral TAK-385 was readily absorbed, and steady-state was reached in ≤14 days. Food reduced TAK-385 systemic exposure by 47%-52%. Mean serum testosterone levels declined ≤6 hours after TAK-385 administration. Loading doses up to 360 mg day 1, or 360 mg day 1 followed by 240 mg day 2 reduced the time to achieve castrate testosterone levels from ≥7 to <3 days. TAK-385 doses ≥80 mg/day achieved sustained medical castration and trough TAK-385 concentrations >4 ng/mL. Following discontinuation of TAK-385 on day 28, testosterone levels normalized in most subjects in ≤28 days. Common adverse events included bradycardia, headache, and hot flush (all grade ≤2).
Conclusions:
Oral TAK-385 (40-180 mg/day) was well tolerated and effectively lowered testosterone in healthy men. Planned phase 2 doses in men with hormone sensitive prostate cancer are 80 and 120 mg/day.
Purpose: We surveyed the growing literature on osteoporosis secondary to androgen deprivation therapy and provide suggestions regarding its identification and treatment. Materials and Methods: We reviewed pertinent studies of male osteoporosis, osteoporotic fracture incidence or bone mineral density loss as a possible side effect of prostate cancer treatment and potential therapies for this side effect. Results: Hypogonadism is a well-known cause of secondary osteoporosis in men. There is evidence of decreased bone mineral density with all types of androgen deprivation therapy, presumably due to its anti-testosterone effect. Bone mineral density loss is 3% to 5% yearly in the first few years of androgen deprivation therapy with an increase in osteoporotic fracture incidence. There are little data on potential treatments, although bisphosphonates and intermittent androgen deprivation therapy may have salutary effects. Conclusions: Osteoporosis is an important and debilitating side effect of androgen deprivation therapy, although precise estimates of its incidence, degree and cost are not completely elucidated. Until more data are available, it is prudent for all men beginning androgen deprivation therapy to receive calcium and vitamin D, and maintain a moderate exercise regimen. Baseline and at least 1 followup bone density measurement seem appropriate with bisphosphonate treatment a possibility in those in whom osteoporosis develops. More research is needed to explore the effect of bisphosphonates, calcium and vitamin D supplementation, exercise, calcitonin, selective estrogen re-uptake inhibitors, estrogens and intermittent androgen deprivation therapy on the course of androgen deprivation therapy induced osteoporosis. The osteoporotic fracture incidence and bone mineral density should be regularly incorporated into studies involving the hormonal treatment of prostate cancer.
Gonadotropin-releasing hormone agonists and antagonists provide androgen-deprivation therapy for prostate cancer. Unlike agonists, gonadotropin-releasing hormone antagonists have a direct mode of action to block pituitary gonadotropin-releasing hormone receptors. There are two licensed gonadotropin-releasing hormone antagonists, degarelix and abarelix. Of these, degarelix is the more extensively studied and has been documented to be more effective than the well-established, first-line agonist, leuprolide, in terms of substantially faster onset of castration, faster suppression of prostate-specific antigen, no risk for testosterone surge or clinical flare, and improved prostate-specific antigen progression-free survival, suggesting a delay in castration resistance. Other than minor injection-site reactions, degarelix is generally well tolerated, without systemic allergic reactions and with most adverse events consistent with androgen suppression or the underlying condition. In conclusion, degarelix provides a rational, first-line androgen-deprivation therapy suitable for the treatment of prostate cancer, with faster onset of castration than with agonists, and no testosterone surge. Furthermore, data suggest that degarelix improves disease control compared with leuprolide, and might delay the onset of castration-resistant disease. In view of these clinical benefits and the lack of need for concomitant anti-androgen treatment, gonadotropin-releasing hormone antagonists might replace gonadotropin-releasing hormone agonists as first-line androgen-deprivation therapy in the future.
Intermittent androgen suppression (IAS) in patients affected by prostate cancer seems to lessen the severity of the side effects that are associated with continuous androgen ablation.
This report monitors the effect of IAS on testosterone values, quality of life, and sexual function during phases of therapy.
A total of 100 patients entered a prospective study of IAS. Androgen blockade was prolonged until a serum prostate specific antigen (PSA) nadir was reached and then resumed for a PSA threshold of 10 ng/mL, in repeated cycles. During I phase, we assessed testosterone levels, well-being with quality-of-life score, and sexual function.
All patients were followed up every 3 months with PSA and total testosterone determinations, and with quality-of-life score using a 10-point questionnaire. Side effects were assessed using yes/no questions. Sexual function was assessed using yes/no questions and in the sexually active patients with International Index of Erectile Function-5 (IIEF).
All patients completed I cycle of treatment (I ON plus I OFF phase). During the OFF phase, 46% of patients showed low testosterone levels, while the others recovered normal testosterone concentrations at a mean of 6.2 months after therapy. There is a negative correlation between baseline PSA values and length of OFF phase and testosterone recovery, and a negative correlation between length of OFF phase and testosterone value during OFF phase. Worsening in Quality of Life (QOL) was significant during active treatment with respect to baseline, but therapy withdrawal showed a positive impact with respect to treatment period. Improvement in quality of life correlated to testosterone recovery and time to testosterone recovery. Fifty-four percent of subjects had normal sexual intercourse at therapy withdrawal, with a correspondence to time to testosterone recovery.
Quality of life and sexual function seem to follow testosterone normalization. These results could have implications in the analysis of IAS.
For patients with advanced prostate cancer, luteinizing hormone-releasing hormone (LHRH) agonists have provided successful androgen deprivation therapy (ADT) for some 25 years. However, the benefits of LHRH agonists are limited in that these agents are agonists, not antagonists. The search for and development of an effective LHRH antagonist have proven difficult. Nevertheless, antagonists offer subtle advantages, including more rapid reduction in testosterone levels, reduction in testosterone-induced flare, and maintenance of castrate levels of testosterone. Accordingly, LHRH antagonists appear to provide a viable alternative to LHRH agonist therapy. Degarelix, a recently approved LHRH antagonist, has been shown to work more quickly in lowering serum testosterone levels, with an acceptable safety profile and a mechanism of action that obviates the testosterone surges associated with LHRH agonist use. Presently, degarelix is the only LHRH antagonist approved for the treatment of advanced prostate cancer.
GnRH and its analogues have led to exciting new avenues of therapy in virtually every subspecialty of internal medicine as well as in gynecology, pediatrics, and urology. Since their discovery in 1971, it has been demonstrated that GnRH and its analogues enable medical professionals to influence the hypothalamic-pituitary-gonadal axis in two distinct classes of therapeutic applications. The first provides natural sequence GnRH in a pulsatile fashion via portable infusion pumps to mimic the normal physiology of hypothalamic GnRH secretion and restores reproductive potential to infertile men and women with disorders of endogenous GnRH secretion. The second mode uses long-acting GnRH agonists administered in a depot delivery to produce a paradoxical desensitization of pituitary gonadotropin secretion which, in turn, results in a complete ablation of the reproductive axis. This biochemical castration induced by GnRH agonist administration is a safe, effective, complete, and reversible method of removing the overlay of gonadal steroids from a variety of diseases which they are known to exacerbate. These diseases include endometriosis and uterine fibroids in women, prostate cancer in men, and precocious puberty in both sexes. This review examines the physiologic and pharmacologic principles underlying the advances produced by these agents, the mechanism of action of GnRH and its analogues at the cellular level, and the individual therapeutic applications to which these analogues have been applied. Because virtually every subspecialty of medicine will be touched by the GnRH analogues, this review provides an overview and background of their use.
Hypothalamic gonadotropin-releasing hormone (GnRH) is a decapeptide that stimulates pituitary synthesis and secretion of gonadotropins and, therefore, gonadal hormones. GnRH antagonists, of which thousands have been formulated, inhibit the hormone from binding to its receptor, inducing a pharmacological hypophysectomy. Peptide derivations of GnRH and non-peptide compounds are both in clinical trials or approved for assisted reproduction. As these compounds reach the market, the use of antagonists might expand to treatment of other hormonally dependent diseases, hormonal male contraception and growth inhibition of extra-pituitary cancer cells expressing GnRH receptors.
The high incidence of prostate cancer makes it a major healthcare problem and the second leading cancer-related cause of death among men in developed countries. The hormonal treatment of prostate cancer is indicated for the palliation of symptomatic and metastatic disease in older patients, and as neoadjuvant treatment of different modalities of radiotherapy. This hormonal treatment is based on the study conducted by Huggins in 1940 and consists of androgen suppression. Since the clinical availability of the first luteinising hormone-releasing hormone (LHRH) agonist, no significant improvement has been made in the field of medical castration. Taking these data into consideration, the recent approval of abarelix by the FDA, the first gonadotrophin-releasing hormone (GnRH) antagonist, appears to be promising news. The pharmacology of the molecule and the clinical studies that led to FDA approval will be reviewed. The place of GnRH antagonists in the treatment modalities of prostate cancer will then be discussed.
To investigate whether testosterone surges occur on repeat injections of 3.6 or 10.8 mg goserelin (Zoladex) depot and, if so, their extent.
Men with prostate cancer for whom hormonal therapy was indicated were randomized to open-label goserelin 3.6 mg every 28 days (n = 129) or 10.8 mg every 84 days (n = 118) for 48 weeks. Serum testosterone and luteinizing hormone levels were measured before repeat injection on day 1 of each treatment cycle and then on days 4 and 8. Surges were defined in three ways: type 1, simultaneous increase in both testosterone and luteinizing hormone to within the age-specific normal range; type 2, increase in testosterone to within the age-specific normal range; and type 3, elevation in testosterone from less than to greater than the castrate level (greater than 18.5 ng/dL).
Most patients did not experience a testosterone surge. Two patients (1.8%) in the 10.8-mg group had a type 1 surge after one repeat injection and two (1.6%) in the 3.6-mg group had a type 2 surge after one repeat injection. Type 3 surges occurred after one or more repeat injections in 34 (27.0%) and 20 (17.7%) patients in the 3.6-mg and 10.8-mg groups, respectively (P = 0.065); the mean surge (+/- standard deviation) was 11.2 ng/dL (+/-13.5) and 17.3 ng/dL (+/-24.6), respectively. No patient with a testosterone surge had clinical symptoms of a tumor flare reaction.
The testosterone levels were consistently maintained within the castrate range (18.5 ng/dL or less) in most (77.4%) patients receiving long-term 3.6 mg or 10.8 mg goserelin.
In order to elucidate the influence of hormone-releasing hormone (LH-RH) agonist therapy cessation on pituitary/testicular function and its clinical implications, we investigated prospectively hormonal (luteinizing hormone: LH; testosterone: T) responses in patients with prostate cancer who received long-term LH-RH 10 agonist therapy.
A consecutive 32 patients who had received LH-RH agonist therapy over 24 months were enrolled. As a baseline, T and LH were measured at the time of LH-RH agonist therapy cessation, monthly for 3 months, and subsequently, every 3 months.
The median duration of LH-RH agonist therapy was 30 months (24-87 months) with median follow-up duration of 24 months following cessation. All patients had castrated T levels and suppressed LH levels at baseline. Median duration of castrated T levels following cessation was 6 months. Median time to normalization of T levels was 24 months. LH levels returned to normal within 3 months in all cases. Patients who received androgen deprivation therapy for 30 months or longer required a longer time for recovery of T levels. Patients over 65 years of age showed a statistically significant longer time for recovery of T levels (P=0.0167).
Long-term LH-RH agonist therapy has remarkable effects on serum T level that last for a significant time after cessation, a fact that should be applied to the interpretation of both PSA and serum T levels after cessation of androgen deprivation therapy.
Health-related quality of life (HQOL) research is a means of broadening the assessment of treatment effects. This longitudinal study investigated the dynamic change to quality of life (QOL) and testosterone dependant physiology in men commencing an intermittent maximal androgen blockade program (IMAB). Two hundred and fifty men were accrued to the multi-centre study of IMAB (Flutamide 250 mg TDS, Leuprolide 22.5 mg depot) ceasing treatment after 9 months if PSA <4 ng/ml, and restarting when PSA >20 ng/ml. QOL was assessed every 3 months for 30 months using the EORTC QLQ-C30 and EORTC QLQ-PR25 module. Data completion for the whole study was 90%. At baseline, our cohort was less symptomatic and had better function than the EORTC reference cohort, which may be related to a shift in clinical practice with time. Testosterone suppression (AS) lead to a significant reduction in global HQOL and deterioration in most function and symptom scales. During the off period, there was a trend of progressive improvement in HQOL that paralleled testosterone recovery but was slower than the rate of deterioration during the treatment phase. Maximum recovery of HQOL occurred most frequently by months 9-12. Testosterone recovery was slower and less complete in older men, and lead to concomitant poorer HOQL recovery. Whilst the magnitude of mean change to scale scores was small, there was a consistent and simultaneous deterioration during maximal androgen blockade (MAB) and improvement during androgen recovery. Older men are more likely to show an impaired testosterone recovery, and this was paralleled by a slower HQOL recovery. Newer methods of analysis to describe results in a way that has meaning to the individual patient are warranted.
To evaluate the process of hormonal recovery after cessation of luteinizing hormone-releasing hormone (LHRH) agonist treatment in patients who had received long-term LHRH agonist therapy for prostate cancer.
Men who had successfully undergone androgen deprivation therapy with only monthly LHRH agonist therapy for > 30 months were enrolled and the administration of LHRH agonist was discontinued. Serum total testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) and prostate-specific antigen (PSA) were measured before the cessation of LHRH agonist therapy and every 4 weeks thereafter, and the administration of LHRH agonist remained suspended until the total testosterone level recovered to > 50 ng/dl.
Ten patients were enrolled in the study. The median (range) castration period and the levels of serum LH, FSH, total testosterone and PSA at cessation of therapy were 39 (30-56) months,<0.5 (<0.5-1.8) mIU/ml, 6.4 (3.0-15.9) mIU/ml, 15.3 (5.8-34.7) ng/dl and 0.13 (0.02-0.89) ng/ml, respectively. Testosterone recovered to > 50 ng/dl in all cases. There were large variations in the times required for recovery of LH and FSH (30-100 days) and serum testosterone (30-330 days). PSA began to increase at various testosterone levels, and there was a large variation (0-83%; median 41%) in the ratio of the androgen suppression (testosterone < 50 ng/dl) time to the period of LHRH agonist cessation.
There was considerable variation in the hypothalamus-pituitary-testicular hormone profiles during recovery from long-term medical castration. These findings are noteworthy when interruption of androgen deprivation therapy is applied with the intention of delaying the progression of hormone-refractory cancer or improving the patient's quality of life.
Androgen deprivation therapy with a gonadotropin-releasing hormone (GnRH) agonist is associated with increased fat mass and insulin resistance in men with prostate cancer, but the risk of obesity-related disease during treatment has not been well studied. We assessed whether androgen deprivation therapy is associated with an increased incidence of diabetes and cardiovascular disease.
Observational study of a population-based cohort of 73,196 fee-for-service Medicare enrollees age 66 years or older who were diagnosed with locoregional prostate cancer during 1992 to 1999 and observed through 2001. We used Cox proportional hazards models to assess whether treatment with GnRH agonists or orchiectomy was associated with diabetes, coronary heart disease, myocardial infarction, and sudden cardiac death.
More than one third of men received a GnRH agonist during follow-up. GnRH agonist use was associated with increased risk of incident diabetes (adjusted hazard ratio [HR], 1.44; P < .001), coronary heart disease (adjusted HR, 1.16; P < .001), myocardial infarction (adjusted HR, 1.11; P = .03), and sudden cardiac death (adjusted HR, 1.16; P = .004). Men treated with orchiectomy were more likely to develop diabetes (adjusted HR, 1.34; P < .001) but not coronary heart disease, myocardial infarction, or sudden cardiac death (all P > .20).
GnRH agonist treatment for men with locoregional prostate cancer may be associated with an increased risk of incident diabetes and cardiovascular disease. The benefits of GnRH agonist treatment should be weighed against these potential risks. Additional research is needed to identify populations of men at highest risk of treatment-related complications and to develop strategies to prevent treatment-related diabetes and cardiovascular disease.
Prostate cancer (PCa) is the most common cancer in men. Androgen-deprivation therapy (ADT) is generally employed in the treatment of locally advanced and metastatic PCa. Although its use as an adjuvant therapy has resulted in improved survival in some patients, ADT has negative consequences. Complications like osteoporosis, sexual dysfunction, gynecomastia, and adverse body composition are well known. Recently, metabolic complications like insulin resistance, diabetes, dyslipidemia, and metabolic syndrome have emerged, which may be responsible for the increased cardiovascular mortality in this population.
A MEDLINE search was conducted for articles published over the last 20 yr based on the key words androgen deprivation therapy AND insulin resistance, hyperglycemia, diabetes, dyslipidemia, metabolic syndrome, and cardiovascular disease. Relevant studies in non-PCa populations evaluating the association between testosterone and metabolism were also reviewed and briefly mentioned where relevant.
Prospective studies evaluating early (3-6 months) metabolic changes of ADT show development of hyperinsulinemia; however, glucose levels remain normal. Cross-sectional studies of men undergoing long-term (> or =12 months) ADT reveal higher prevalence of diabetes and metabolic syndrome compared with controls. Furthermore, men undergoing ADT also experience higher cardiovascular mortality.
Long-term prospective studies of ADT are needed to determine the timing of onset of these metabolic complications and to investigate the mechanism behind them. In the meantime, we recommend baseline and serial screening for fasting glucose, lipids, and other cardiovascular risk factors in men receiving ADT. Glucose tolerance tests and cardiac evaluation may be required in selected cases.
The efficacy and safety of degarelix: a 12-month, comparative, randomized, open-label, parallel-group phase III study in patients with prostate cancer
- Klotz