Gonadotropin-releasing hormone agonist plus "add-back" hormone replacement therapy for treatment of endometriosis: a prospective, randomized, placebo-controlled, double-blind trial

Gonadotropin-releasing hormone analogues for endometriosis

BACKGROUND

Endometriosis is a common gynaecological condition affecting 6 to 11% of reproductive-age women and may cause dyspareunia, dysmenorrhoea, and infertility. One treatment strategy is medical therapy with gonadotrophin-releasing hormone analogues (GnRHas) to reduce pain due to endometriosis. One of the adverse effects of GnRHas is a decreased bone mineral density. In addition to assessing the effect on pain, quality of life, most troublesome symptom and patients' satisfaction, the current review also evaluated the effect on bone mineral density and risk of adverse effects in women with endometriosis who use GnRHas versus other treatment options.

OBJECTIVES

To assess the effectiveness and safety of GnRH analogues (GnRHas) in the treatment of painful symptoms associated with endometriosis and to determine the effects of GnRHas on bone mineral density of women with endometriosis.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO and the trial registries in May 2022 together with reference checking and contact with study authors and experts in the field to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) which compared GnRHas with other hormonal treatment options, including analgesics, danazol, intra-uterine progestogens, oral or injectable progestogens, gestrinone and also GnRHas compared with no treatment or placebo. Trials comparing GnRHas versus GnRHas in conjunction with add-back therapy (hormonal or non-hormonal) or calcium-regulation agents were also included in this review.  DATA COLLECTION AND ANALYSIS: We used standard methodology as recommended by Cochrane. Primary outcomes are relief of overall pain and the objective measurement of bone mineral density. Secondary outcomes include adverse effects, quality of life, improvement in the most troublesome symptoms and patient satisfaction.  Due to high risk of bias associated with some of the studies, primary analyses of all review outcomes were restricted to studies at low risk of selection bias. Sensitivity analysis including all studies was then performed.

MAIN RESULTS

Seventy-two studies involving 7355 patients were included. The evidence was very low to low quality: the main limitations of all studies were serious risk of bias due to poor reporting of study methods, and serious imprecision.  Trials comparing GnRHas versus no treatment  We did not identify any studies. Trials comparing GnRHas versus placebo There may be a decrease in overall pain, reported as pelvic pain scores (RR 2.14; 95% CI 1.41 to 3.24, 1 RCT, n = 87, low-certainty evidence), dysmenorrhoea scores (RR 2.25; 95% CI 1.59 to 3.16, 1 RCT, n = 85, low-certainty evidence), dyspareunia scores (RR 2.21; 95% CI 1.39 to 3.54, 1 RCT, n = 59, low-certainty evidence), and pelvic tenderness scores (RR 2.28; 95% CI 1.48 to 3.50, 1 RCT, n = 85, low-certainty evidence) after three months of treatment. We are uncertain of the effect for pelvic induration, based on the results found after three months of treatment (RR 1.07; 95% CI 0.64 to 1.79, 1 RCT, n = 81, low-certainty evidence). Besides, treatment with GnRHas may be associated with a greater incidence of hot flushes at three months of treatment (RR 3.08; 95% CI 1.89 to 5.01, 1 RCT, n = 100, low-certainty evidence). Trials comparing GnRHas versus danazol For overall pain, for women treated with either GnRHas or danazol, a subdivision was made between pelvic tenderness, partly resolved and completely resolved. We are uncertain about the effect on relief of overall pain, when a subdivision was made for overall pain (MD -0.30; 95% CI -1.66 to 1.06, 1 RCT, n = 41, very low-certainty evidence), pelvic pain (MD 0.20; 95% CI -0.26 to 0.66, 1 RCT, n = 41, very low-certainty evidence), dysmenorrhoea (MD 0.10; 95% CI -0.49 to 0.69, 1 RCT, n = 41, very low-certainty evidence), dyspareunia (MD -0.20; 95% CI -0.77 to 0.37, 1 RCT, n = 41, very low-certainty evidence), pelvic induration (MD -0.10; 95% CI -0.59 to 0.39, 1 RCT, n = 41, very low-certainty evidence), and pelvic tenderness (MD -0.20; 95% CI -0.78 to 0.38, 1 RCT, n = 41, very low-certainty evidence) after three months of treatment. For pelvic pain (MD 0.50; 95% CI 0.10 to 0.90, 1 RCT, n = 41, very low-certainty evidence) and pelvic induration (MD 0.70; 95% CI 0.21 to 1.19, 1 RCT, n = 41, very low-certainty evidence), the complaints may decrease slightly after treatment with GnRHas, compared to danazol, for six months of treatment. Trials comparing GnRHas versus analgesics  We did not identify any studies. Trials comparing GnRHas versus intra-uterine progestogens We did not identify any low risk of bias studies. Trials comparing GnRHas versus GnRHas in conjunction with calcium-regulating agents There may be a slight decrease in bone mineral density (BMD) after 12 months treatment with GnRHas, compared to GnRHas in conjunction with calcium-regulating agents for anterior-posterior spine (MD -7.00; 95% CI -7.53 to -6.47, 1 RCT, n = 41, very low-certainty evidence) and lateral spine (MD -12.40; 95% CI -13.31 to -11.49, 1 RCT, n = 41, very low-certainty evidence).  AUTHORS' CONCLUSIONS: For relief of overall pain, there may be a slight decrease in favour of treatment with GnRHas compared to placebo or oral or injectable progestogens. We are uncertain about the effect when comparing GnRHas with danazol, intra-uterine progestogens or gestrinone. For BMD, there may be a slight decrease when women are treated with GnRHas, compared to gestrinone. There was a bigger decrease of BMD in favour of GnRHas, compared to GnRHas in conjunction with calcium-regulating agents. However, there may be a slight increase in adverse effects when women are treated with GnRHas, compared to placebo or gestrinone. Due to a very low to low certainty of the evidence, a wide range of outcome measures and a wide range of outcome measurement instruments, the results should be interpreted with caution.

Use of dienogest in endometriosis: a narrative literature review and expert commentary

Objective: Endometriosis affects up to 10% of women of reproductive age, and the main goal of treatment is to relieve symptoms. Progestins have been the mainstay of endometriosis suppression, of which dienogest has become an important option in many parts of the world. This is an expert literature review, with recommendations on the use of dienogest in the context of various clinical considerations when treating endometriosis.Methods: A search of PubMed was conducted for papers published between 2007 and 2019 on the use of dienogest in endometriosis. Experts reviewed these and included those they considered most relevant in clinical practice, according to their own clinical experience.Results: Evidence regarding the long-term use (>15 months) of dienogest for the management of endometriosis is presented, with experts concluding that the efficacy of dienogest should be assessed primarily on its impact on pain and quality of life. Fertility preservation, the option to avoid or delay surgery, and managing bleeding irregularities that can occur with this treatment are also considered. Counseling women on potential bleeding risks before starting treatment may be helpful, and evidence suggests that few women discontinue treatment for this reason, with the benefits of treatment outweighing any impact of bleeding irregularities.Conclusions: Overall, the evidence demonstrates that dienogest offers an effective and tolerable alternative or adjunct to surgery and provides many advantages over combined hormonal contraceptives for the treatment of endometriosis. It is important that treatment guidelines are followed and care is tailored to the woman's individual needs and desires.

Adhesion in Physiological, Benign and Malignant Proliferative States of the Endometrium: Microenvironment and the Clinical Big Picture

Although the developments in cellular and molecular biology over the last few decades have significantly advanced our understanding of the processes and players that regulate invasive disease, many areas of uncertainty remain. This review will discuss the contribution of dysregulated cell⁻cell and cell⁻matrix adhesion to the invasion in both benign and malignant contexts. Using the endometrium as an illustrative tissue that undergoes clinically significant invasion in both contexts, the adhesion considerations in the cells ("seed") and their microenvironment ("soil") will be discussed. We hope to orientate this discussion towards translational relevance for the diagnosis and treatment of endometrial conditions, which are currently associated with significant morbidity and mortality.

A focus on the distinctions and current evidence of endometriosis in adolescents

Endometriosis (EM) occurring in adolescents presents distinct clinical and histologic characteristics compared to the disease in women. Because the symptoms of EM are nonspecific, often overlapping with those experienced in a range of gynecological and gastrointestinal conditions, the process of reaching a diagnosis of EM is often delayed. The diagnosis of EM is suspected depending on the history and the symptoms and signs, is corroborated by physical examination and imaging techniques, and is finally proved by histological examination of specimens collected during laparoscopy. Currently, there is insufficient evidence to make strong recommendations for management in adolescents who may have EM. This short report reviews some peculiarities of EM in adolescents and provides an update of recent knowledge of the diagnosis and treatment of EM. We hope that the present contribution may help to bring more attention to the clinical diagnosis of EM and consequently aid in decreasing diagnostic delay.

Pain Associated with Endometriosis: Therapeutic Options

Defined as the presence of functional endometrial tissue outside the uterine cavity, endometriosis is a chronic and recurrent disease that affects 7–10% of reproductive-age women, causing pain, infertility or both, resulting in serious life disruption, emotional and physical suffering, and decreased productivity. The observation that endometriosis is more common in women with early ménarche, polymenorrhea, outflow genital tract obstruction or a family history of disease suggests that its development depends on the complex interaction of genetic, immunological, environmental and hormonal factors. Current therapies for the management of endometriosis are medical, surgical or both. Medical therapies induce a hypoestrogenic state to reduce menstrual flow and apoptosis of endometriotic lesions. They include androgenic or progestational compounds and gonadotropin-releasing hormone analogs, which are comparably effective but have very different adverse-effect profiles. Consequently, the choice of which medical treatment to prescribe may not be based on differences in efficacy but on differences in tolerability, safety and, when everything else is equal, cost. Although surgery to remove endometriosis is effective in relieving pain and restoring fertility, recurrence of symptoms is common and repeated medical and surgical interventions are often needed. The need for additional surgery may be reduced by the thorough excision of all lesions and disease at the initial surgery, followed by the postoperative administration of hormonal suppressive therapy with progestins to induce hypomenorrhea or amenorrhea. Definitive surgery with hysterectomy and removal of ovaries is frequently curative. Future therapies should be directed at identifying women at risk for the disease and implementing interventions that will prevent disease development altogether. Ultimately, the goal is to make endometriosis a disease of the past.

Gonadotropin-releasing hormone agonist with add-back treatment is as effective and tolerable as dienogest in preventing pain recurrence after laparoscopic surgery for endometriosis

PURPOSE

This study was performed to compare the efficacy and tolerability of GnRH agonist with add-back therapy versus dienogest treatment for preventing pelvic pain recurrence after laparoscopic surgery for endometriosis.

METHODS

Sixty-four reproductive-aged women who underwent laparoscopic surgery for endometriosis received post-operative medical treatment with either GnRH agonist plus 17β-estradiol and norethisterone acetate (n = 28) or dienogest (n = 36) for 6 months. The pre- to post-treatment changes in pain were assessed using a visual analogue scale, and changes in quality-of-life and menopausal symptoms were measured by questionnaire.

RESULTS

Visual analogue scale pain score decreased significantly for both treatments with no significant differences between groups. Neither physical, psychological, social, and environmental components of quality-of-life nor menopausal rating scale score were significantly different between the two groups. Bone mineral density at the lumbar spine declined significantly in both treatment groups (-2.5 % for GnRH agonist plus add-back and -2.3 % for dienogest), with no significant difference between the two groups.

CONCLUSION

GnRH agonist and add-back therapy using 17β-estradiol and norethisterone acetate are as effective and tolerable as dienogest for the prevention of pelvic pain recurrence after laparoscopic surgery for endometriosis.

Body composition and bone mineral density after ovarian hormone suppression with or without estradiol treatment

OBJECTIVE

Suppression of ovarian hormones in premenopausal women on gonadotropin-releasing hormone agonist (GnRH(AG)) therapy can cause fat mass (FM) gain and fat-free mass (FFM) loss. Whether this is specifically caused by a decline in serum estradiol (E2) is unknown. This study aims to evaluate the effects of GnRH(AG) with placebo (PL) or E2 add-back therapy on FM, FFM, and bone mineral density (BMD). Our exploratory aim was to evaluate the effects of resistance exercise training on body composition during the drug intervention.

METHODS

Seventy healthy premenopausal women underwent 5 months of GnRH(AG) therapy and were randomized to receive transdermal E2 (GnRH(AG) + E2, n = 35) or PL (GnRH(AG) + PL, n = 35) add-back therapy. As part of our exploratory aim to evaluate whether exercise can minimize the effects of hormone suppression, some women within each drug arm were randomized to undergo a resistance exercise program (GnRH(AG) + E2 + Ex, n = 12; GnRH(AG) + PL + Ex, n = 12).

RESULTS

The groups did not differ in mean (SD) age (36 [8] and 35 [9] y) or mean (SD) body mass index (both 28 [6] kg/m). FFM declined in response to GnRH(AG) + PL (mean, -0.6 kg; 95% CI, -1.0 to -0.3) but not in response to GnRH(AG) + E2 (mean, 0.3 kg; 95% CI, -0.2 to 0.8) or GnRH(AG) + PL + Ex (mean, 0.1 kg; 95% CI, -0.6 to 0.7). Although FM did not change in either group, visceral fat area increased in response to GnRH(AG) + PL but not in response to GnRH(AG) + E2. GnRH(AG) + PL induced a decrease in BMD at the lumbar spine and proximal femur that was prevented by E2. Preliminary data suggest that exercise may have favorable effects on FM, FFM, and hip BMD.

CONCLUSIONS

Suppression of ovarian E2 results in loss of bone and FFM and expansion of abdominal adipose depots. Failure of hormone suppression to increase total FM conflicts with previous studies of the effects of GnRH(AG). Further research is necessary to understand the role of estrogen in energy balance regulation and fat distribution.

Minimising menopausal side effects whilst treating endometriosis and fibroids

Medical management of endometriosis and fibroids involves manipulation of the hypothalamic-pituitary-gonadal axis to alter the balance of sex hormones thereby inhibiting disease progression and ameliorate symptoms. Unfortunately, resultant menopausal symptoms sometimes limit the tolerability and duration of such treatment. The use of gonadotrophin-releasing hormone agonists to treat these diseases can result in short-term hypoestrogenic and vasomotor side effects as well as long-term impacts on bone health and cardiovascular risk. The routine use of add-back hormone replacement has reduced these risks and increased patient compliance, making this group of drugs more useful as a medium-term treatment option. The estrogen threshold hypothesis highlights the concept of a 'therapeutic window' in which bone loss is minimal but the primary disease is not aggravated. It explains why add-back therapy is appropriate for such patients and helps to explain the basis behind new developments in the treatment of hormonally responsive gynaecological conditions such as gonadotrophin-releasing hormone antagonists and progesterone receptor modulators.

Effects of different add-back regimens on hypoestrogenic problems by postoperative gonadotropin-releasing hormone agonist treatment in endometriosis

Objective

To compare the efficacy of different add-back regimens on hypoestrogenic symptoms during postoperative gonadotropin-releasing hormone (GnRH) agonist treatment in endometriosis patients.

Methods

This prospective cohort study included reproductive-aged women who underwent conservative laparoscopic surgery for ovarian endometriosis and received add-back therapy during a 6-month course of GnRH agonist therapy after surgery. Participants received one of four different add-back regimens: 1 mg of estradiol valerate, 2.5 mg of tibolone, or a combination of 1 mg of estradiol and 2 mg of drospirenone or 0.5 mg of norethisterone acetate. Changes in quality of life, hypoestrogenic symptoms, and bone mineral density were compared according to add-back regimens.

Results

A total of 57 participants completed a 6-month course of GnRH agonist and add-back therapy. All components of quality of life did not differ across groups. However, within the same treatment group, social relationship factors decreased significantly with estradiol valerate and tibolone alone, and environmental factors decreased significantly with estradiol valerate alone. Menopausal Rating Scale score did not change significantly, but the incidence of hot flushes significantly decreased with a combination of estradiol and norethisterone acetate. Bone mineral densities at the lumbar spine declined significantly after treatment in all groups except with a combination of estradiol and norethisterone acetate.

Conclusion

This preliminary study suggests that an add-back regimen containing estradiol valerate and norethisterone acetate may have better efficacy in terms of quality of life, hypoestrogenism-associated symptoms, and bone mineral density.

Analogs of Luteinizing Hormone-Releasing Hormone in the Treatment of Endometriosis

Agonists of luteinizing hormone-releasing hormone (LHRH) induce a reversible hypoestrogenic state through the down-regulation of LHRH receptors and desensitization of the pituitary. Since endometrial implants are estrogen sensitive, LHRH agonists have frequently been used for medical treatment of endometriosis. Nowadays, LHRH agonists can be considered in general as a second-line medical treatment for endometriosis-related symptoms, as oral therapy with dienogest is as effective and has fewer side effects. However, therapy with LHRH agonists for 3-6 months prior to in vitro fertilization remains the treatment of choice in patients with endometriosis, as it significantly increases pregnancy rates.

LHRH agonists are used prior to surgery and as an adjuvant after an operation to prevent recurrence or prolong disease-free intervals. Adverse effects of LHRH agonists are due to hypoestrogenism and include hot flushes, vaginal dryness, loss of libido, sleep disturbances and a diminished bone density which limits the duration of their administration to 6 months. For long-term treatment, add-back of estrogen and/or progestin,/or progestin only with or without bisphosphonates, can be used, but existing studies only cover a 12-month period of treatment.

LHRH antagonists competitively block the pituitary receptors for LHRH. Consequently, a partial pharmacological hypophysectomy with a reduction of the estrogen levels to a desired level is possible if LHRH antagonists are adequately dosed. As endometriotic implants require relatively high levels of estrogen, partially lower plasma levels of estrogens are sufficient to prevent the loss of bone density. A long-term treatment without add-back therapy is also possible.

Emerging therapy for endometriosis

INTRODUCTION

Endometriosis is a chronic disease manifested by pain and infertility due to ectopic implantation of endometrial glands and stroma causing inflammation. Treatment of endometriosis utilizes a significant amount of health-care resources and requires chronic therapy. Management involves a combination of surgical and medical interventions and requires long-term treatment to avoid repeated surgeries.

AREAS COVERED

Whereas medical therapies exist for management of endometriosis-related pain, each class has its limitations including side effects, cost, and known duration of relief of symptoms. Development of effective, well-tolerated medical therapies that are appropriate for long-term use is crucial to provide adequate treatment for this chronic disease. This review discusses the various medical therapies available, their limitations, and emerging therapies being developed to address many of these concerns.

EXPERT OPINION

The authors recommend chronic suppressive therapy for management of endometriosis symptoms, particularly in the postoperative setting. Empiric treatment is appropriate for those patients without evidence of severe disease. Currently available option may not be effective for nor tolerated by all patients. Newer compounds, including gonadotropin-releasing antagonists and aromatase inhibitors combined with hormonal contraceptives, offer possible alternatives to currently available therapies.

Clinical efficacy of add-back therapy in treatment of endometriosis: a meta-analysis

OBJECTIVE

A meta-analysis was conducted to determine the effectiveness of using gonadotropin-releasing hormone analogues (GnRH-a), both with and without hormonal add-back therapy, for the management of endometriosis.

METHODS

Cochrane library, Ovid (Embase) and Pubmed databases were searched between the years 1998 and 2013 for published, prospective, randomised controlled trials (RCT) that assessed the effectiveness of "add-back" therapy for EMs treatment. The meta-analysis was performed using RevMan V5.0. The main outcome measures were as follows: lumbar spine bone mineral density (BMD) immediately after treatment and after 6 months of follow-up; femoral neck BMD; serum estradiol levels; changes in the Kupperman index score; the pelvic pain score, including dysmenorrhoea and dyspareunia; and pelvic tenderness.

RESULTS

A total of 13 RCT, including 945 participants, were identified. The evidence suggested that "add-back" therapy was more effective for symptom relief than GnRH-a alone. BMD was significantly different when comparing "add-back" therapy to GnRH-a alone, both immediately after treatment and at 6 months. The "add-back" therapy increased serum oestrogen and did not reduce the efficacy of GnRH-a for treating dysmenorrhoea and dyspareunia. A variety of add-back regimens had a same effect for the treatment of endometriosis.

CONCLUSIONS

"Add-back" therapy, based on the GnRH-a dose, does not reduce the efficacy of using GNRH-a for the management of endometriosis. "Add-back" therapy reduced the occurrence of side effects that can occur with GnRH-a therapy alone, such as osteoporosis and menopausal syndrome. There were no statistically significant differences when comparing the effectiveness of a variety of "add-back" regimens to each other.

The use of gonadotropin releasing hormone analogues in adolescent and young patients with endometriosis

PURPOSE OF REVIEW

Endometriosis is increasingly being recognized and diagnosed in adolescents. As a result of this earlier diagnosis, treatment with agents like gonadotropin releasing hormone agonist (GnRHa) begins earlier and may last longer. Long-term effects of GnRHa treatment for endometriosis are of concern when treating adolescents.

RECENT FINDINGS

GnRHas are used for adolescents with surgically confirmed endometriosis. GnRHa treatment is effective for pain reduction, but is associated with menopausal symptoms and decreases in bone density. Different regimens of hormonal add-back therapy have been studied in adults to attempt to prevent these side-effects.

SUMMARY

GnRHa therapy is a highly effective, nonsurgical treatment option for many adolescents with endometriosis, but is accompanied by side-effects of bone loss and menopausal symptoms. Side-effects may be decreased by introducing appropriate add-back therapy. Monitoring of bone density by DXA is recommended for prolonged use of GnRHa in adolescents.

Current and future applications of GnRH, kisspeptin and neurokinin B analogues

Reproductive hormones affect all stages of life from gamete production, fertilization, fetal development and parturition, neonatal development and puberty through to adulthood and senescence. The reproductive hormone cascade has, therefore, been the target for the development of numerous drugs that modulate its activity at many levels. As the central regulator of the cascade, gonadotropin-releasing hormone (GnRH) agonists and antagonists have found extensive applications in treating a wide range of hormone-dependent diseases, such as precocious puberty, prostate cancer, benign prostatic hyperplasia, endometriosis and uterine fibroids, as well as being an essential component of in vitro fertilization protocols. The neuroendocrine peptides that regulate GnRH neurons, kisspeptin and neurokinin B, have also been identified as therapeutic targets, and novel agonists and antagonists are being developed as modulators of the cascade upstream of GnRH. Here, we review the development and applications of analogues of the major neuroendocrine peptide regulators of the reproductive hormone cascade: GnRH, kisspeptin and neurokinin B.

Will GnRH antagonists assist in the treatment of benign gynaecological diseases?

While GnRH agonists have become well-established tools for preoperative treatment of uterine fibroids or postoperative treatment in endometriosis for 3-6 months, GnRH antagonists seem to offer important advantages due to their specific pharmacological mode of action. Avoiding any flare-up effect, it seems to be possible to reduce treatment time to about only 2-4 weeks in the case of fibroids to obtain a clinically relevant reduction in size. Furthermore, due to the classic competitive receptor blockade induced by GnRH antagonists, it is feasible to preserve residual oestradiol secretion for a period of 8 weeks in patients with endometriosis. Endometriosis patients undergoing this treatment reported a symptom-free period, with no signs of mood changes, hot flushes, loss of libido, vaginal dryness or other symptoms. Serum oestradiol oscillated around a mean level of 50 pg/ml during therapy. Sequential administration of the GnRH antagonist cetrorelix (Cetrotide), in a 3 mg dosage once weekly over 8 weeks in the case of endometriosis or administration every 4th day for a time span of 2-4 weeks for fibroids, creates a new opportunity for medical treatment. Although 3 mg of cetrorelix acetate obviously acts as an intermediate depot preparation, results obtained so far are very preliminary.

Model-based drug development: a rational approach to efficiently accelerate drug development

The pharmaceutical industry continues to face significant challenges. Very few compounds that enter development reach the marketplace, and the investment required for each success can surpass $1.8 billion. Despite attempts to improve efficiency and increase productivity, total investment continues to rise whereas the output of new medicines declines. With costs increasing exponentially through each development phase, it is failure in phase II and phase III that is most wasteful. In today's development paradigm, late-stage failure is principally a result of insufficient efficacy. This is manifested as either a failure to differentiate sufficiently from placebo (shown for both novel and precedented mechanisms) or a failure to demonstrate sufficient differentiation from existing compounds. Set in this context, this article will discuss the role model-based drug development (MBDD) approaches can and do play in accelerating and optimizing compound development strategies through a series of illustrative examples.

Integrated pharmacometrics and systems pharmacology model-based analyses to guide GnRH receptor modulator development for management of endometriosis

Endometriosis is a gynecological condition resulting from proliferation of endometrial-like tissue outside the endometrial cavity. Estrogen suppression therapies, mediated through gonadotropin-releasing hormone (GnRH) modulation, decrease endometriotic implants and diminish associated pain albeit at the expense of bone mineral density (BMD) loss. Our goal was to provide model-based guidance for GnRH-modulating clinical programs intended for endometriosis management. This included developing an estrogen suppression target expected to provide symptomatic relief with minimal BMD loss and to evaluate end points and study durations supportive of efficient development decisions. An existing multiscale model of calcium and bone was adapted to include systematic estrogen pharmacologic effects to describe estrogen concentration-related effects on BMD. A logistic regression fit to patient-level data from three clinical GnRH agonist (nafarelin) studies described the relationship of estrogen with endometrial-related pain. Targeting estradiol between 20 and 40 pg/ml was predicted to provide efficacious endometrial pain response while minimizing BMD effects.

Management of Endometriosis-Related Pain: An Update

Endometriosis is a chronic and recurrent condition affecting 6–10% of women of a reproductive age. It results from implantation of endometrial tissue outside the uterine cavity. It is associated with pelvic pain and infertility. Treatment for endometriosis ranges from medical management, to conservative surgery, to definitive surgery with a hysterectomy and bilateral salpingo-oophorectomy, and should be based on patient's fertility desires and tolerance. Medical treatment involves hormonal manipulation to induce a hypoestrogenic or antiestrogenic state to induce regression and apoptosis of lesions. Endometriosis can have dire effects on women's lives and productivity; this article will focus on early diagnosis, treatment and prevention of recurrence of the disease.

Gonadotropin-releasing hormone agonist and add-back therapy: what do the data show?

PURPOSE OF REVIEW

Endometriosis is a gynecologic disorder that can lead to debilitating chronic pelvic pain and infertility. Gonadotropin-releasing hormone agonists (GnRHa) have emerged as a primary medical therapy for patients with symptomatic disease, but secondary hypoestrogenic side effects may limit compliance. Add-back therapy is a means of surmounting this problem.

RECENT FINDINGS

Progestins such as norethindrone acetate may be administered with or without addition of low doses of estrogens to safely and effectively extend GnRHa therapy while minimizing side effects. Recent studies have demonstrated that the use of add-back enhances compliance and duration of therapy. The initiation of an add-back should not be deferred given evidence demonstrating an increase in vasomotor symptoms and bone loss if not administered concomitantly. The subset of adolescents with endometriosis who require GnRHa therapy should be administered an add-back, but require careful monitoring of bone mineral density.

SUMMARY

Implementation of an appropriately selected add-back will significantly reduce hypoestrogenic side effects, enhance compliance, and allow for prolongation of therapy without interfering with the efficacy of GnRHa in treating symptomatic endometriosis.

Endometriosis: Necessary and Sequential Therapeutic Procedures and Guidelines

Objectives

TO define the actual guidelines about the therapy of endometriosis. Methods. A brief review of the literature for the correct diagnosis of endometriosis and the medical and surgical approach.

Results

It is well accepted that the gold standard of endometriosis diagnosis is the direct vision of the disease with laparoscopy or the presence of endometriosis implants in vagina or cervix. Staging must be performed along with the distribution, and depth and bowel involvement must be noted. Symptoms intensity is not related to the degree of endometriosis. Therapy, medical or surgical, should be chosen in relation to symptoms and the disease degree, keeping in mind that surgery is the approach that may offer better results.

Conclusions

The direct vision of the disease is the only method to obtain the correct diagnosis and an accurate staging. However, ultrasound can be helpful in cases of pelvic localization and in the follow-up of the disease. Moreover, MRI can be employed, especially in cases with particular endometriosis implant, e.g. gluteus muscle. Surgery offers the best results but some medical therapy, especially hormonal therapy, is often employed for the relief of pains.

Current pharmacotherapy for endometriosis

IMPORTANCE OF THE FIELD

Medical therapy is the most commonly used treatment for endometriosis. In particular, the administration of hormonal therapies aims to improve symptoms with minimal adverse effects.

AREAS COVERED IN THIS REVIEW

Observational and randomized studies evaluating the efficacy of medical therapy on symptoms associated with endometriosis were reviewed. We searched Medline, Embase and the Cochrane Library up to December 2009.

WHAT THE READER WILL GAIN

The reader will obtain information on the available medical therapies used to treat endometriosis-related symptoms either after surgery or as an alternative to the surgical excision of endometriosis. The effectiveness of therapies, the dose of drugs, the length of treatment and the adverse effects are examined.

TAKE HOME MESSAGE

Medical therapies can efficaciously reduce the severity of pain symptoms caused by endometriosis. Recurrence of symptoms is common after discontinuation of medical therapies; therefore, the choice of the therapy should be based not only on the improvements of symptoms but also on the potential adverse effects and patients' satisfaction.

The incidence and characteristics of uterine bleeding during postoperative GnRH agonist treatment combined with tibolone add-back therapy in endometriosis patients of reproductive age

OBJECTIVES

This study was undertaken to evaluate the incidence and the factors associated with uterine bleeding while taking GnRH agonist treatment combined with tibolone add-back therapy in endometriosis patients of reproductive age.

STUDY DESIGN

The medical records of 188 endometriosis (stages III-IV) patients of reproductive age receiving postoperative GnRH agonist treatment combined with tibolone add-back therapy for 6 months were reviewed. Clinical features were analyzed and compared between the two groups: Group A, patients without an episode of uterine bleeding (n=137) and Group B, patients that had experienced uterine bleeding (n=51).

RESULTS

Demographic profiles were not different in the two groups. The incidence of uterine bleeding was 27.1% and irregular spotting was the most frequent bleeding pattern. The proportion of patients who received ovarian surgery during pelviscopy was higher in Group B (p<0.05), but other clinical characteristics were not different between two groups.

CONCLUSIONS

The incidence of uterine bleeding was 27.1%. And, the proportion of patients who received ovarian surgery was higher in patients with uterine bleeding.

GnRH analogs: options for endometriosis-associated pain treatment

While none of the currently available treatment options for endometriosis pain resolved the underlying disease process, there are growing numbers of medical alternatives available. Medical options include the GnRH agonists and antagonists. Review of these treatments in the management of endometriosis pain and the insight often to the etiology of endometriosis are presented for discussion.

Treatment of dysfunctional uterine bleeding in the perimenopause: the effects of adding combined estradiol/norethisterone acetate therapy to goserelin acetate treatment--a randomized, placebo-controlled, double-blind trial

OBJECTIVE

To assess the effects of adding combined estradiol/norethisterone acetate therapy (CENT) to goserelin acetate treatment (GA) of dysfunctional uterine bleeding (DUB) in perimenopausal women.

METHODS

In a randomized, placebo-controlled, double-blind trial followed by an open follow-up study, 31 perimenopausal women with DUB were recruited from gynecological outpatient departments of two Dutch hospitals and randomized for treatment with either GA/placebo or GA/CENT for 6 months followed by 18 months of GA/CENT for all. The main outcome measures were abdominal pain, number of bleeding days, double-layer endometrial thickness (DET), Greene climacteric score (GCS), visual analog scale for well-being, bone mineral density (BMD) and mammographic density (BI-RAD score).

RESULTS

Abdominal pain, number of bleeding days and DET decreased in both groups, the between-group difference in decrease not being statistically significant. GCS initially showed significant improvement in the GA/CENT group. BMD decreased significantly in the GA/placebo group (-4.1%) compared with the GA/CENT group (-0.3%). Another 18 months of GA/CENT did not result in a lasting difference in BMD between groups. BI-RAD scores did not differ significantly between or within the two groups.

CONCLUSIONS

Adding CENT to GA treatment for DUB in perimenopausal women initially prevented BMD loss and improved climacteric complaints, while having no negative impact on vaginal bleeding, abdominal pain or BI-RAD scores. However, prolonged treatment did not result in a lasting prevention of bone loss.

Cetrorelix in the treatment of female infertility and endometriosis

The use of cetrorelix within ovarian-stimulation protocols demonstrates several advantages compared with gonadotropin-releasing hormone (GnRH) agonist-containing protocols, which include, for example, significantly less time for analogue treatment and a reduction in the amount of gonadotropins needed. Furthermore, fewer side effects can be expected. There is no difference regarding endometrium quality and hormone profiles, and the results of assisted reproduction cycles are comparable. Cetrorelix also seems to be useful in the treatment of endometriosis which, in most cases, is an estrogen-dependent disease. Furthermore, fewer side effects occur with this agent (e.g., postmenopausal symptoms) and no estradiol add-back is needed. In the future, new nonpeptic GnRH antagonists are expected to be available for oral administration. Although they are still under investigation, these agents have the potential to improve patients' comfort and compliance.

Emerging drugs in endometriosis

Endometriosis is a common, estrogen-dependent, gynaecological disease, defined as the presence of endometrial-like tissue outside the uterus. Although several medications are used for treatment of the disease, they are associated with high recurrence rates, considerable side effects and limited duration of application. Due to these limitations and to the impact of endometriosis on the quality of life of affected women, their environment and the society, there is a great need for new drugs able to abolish endometriosis and its symptoms. Studies in recent years investigating the (patho)physiological mechanisms involved in disease aetiology have fostered the development of novel therapeutic concepts for endometriosis, by targeting the hypothalamic-pituitary-gonadal axis, by selective modulation of estrogenic and progestogenic pathways, by inhibiting angiogenesis or by interfering with inflammatory and immunological factors. This article presents a brief summary of the currently available medications and an overview regarding the development of some of the most interesting and/or most promising novel drug candidates for endometriosis.

Gonadal protection by a gonadotropin-releasing hormone agonist depot in young women with Hodgkin's disease undergoing chemotherapy

OBJECTIVE

To explore the effects of a gonadotropin-releasing hormone (GnRH) agonist depot (goserelin acetate) in women with Hodgkin's disease receiving chemotherapy while taking a continuous combined estrogen-progestin preparation as add-back on the prevention of premature ovarian failure (POF).

METHODS

In a prospective pilot study, five premenopausal women with Hodgkin's disease received a GnRH agonist depot plus add-back until polychemotherapy was completed. Every 4 weeks during treatment and thereafter, a hormonal profile (follicle-stimulating hormone (FSH), luteinizing hormone, 17beta-estradiol, progesterone and inhibin B) was measured until resumption of menstruation or the development of a hypergonadotropic state (2 x FSH > 30 U/l).

RESULTS

All patients reached prepubertal status during treatment. After discontinuation of goserelin acetate, one patient developed a hypergonadotropic state and four patients resumed menstruation. One of those patients became pregnant and delivered a healthy son.

CONCLUSIONS

The effectiveness of GnRH agonist plus add-back on the prevention of POF during polychemotherapy in women with Hodgkin's disease needs further elucidation in randomized controlled trials. The results of our pilot study are promising.

Add-back therapy in the treatment of endometriosis-associated pain

OBJECTIVE

To determine the efficacy of GnRH analogue plus add-back therapy compared with GnRH analogue alone and estroprogestin in patients with relapse of endometriosis-associated pain.

DESIGN

Randomized, controlled study.

SETTING

University hospital.

PATIENT(S)

One hundred thirty-three women with relapse of endometriosis-related pain after previous endometriosis surgery.

INTERVENTION(S)

Forty-six women were treated with GnRH analogue plus add-back therapy, 44 women were given GnRH analogue alone, and 43 women received estroprogestin, for 12 months.

MAIN OUTCOME MEASURE(S)

Pain evaluation by a visual analogue scale, quality of life in treated patients according to the SF-36 questionnaire, and occurrence of adverse effects, including bone mass density loss, at pretreatment, after 6 months of treatment, at the end of treatment (12 months), and 6 months after discontinuation of treatment.

RESULT(S)

Patients treated either with GnRH analogue alone or GnRH analogue plus add-back therapy showed a higher reduction of pelvic pain, dysmenorrhea, and dyspareunia than patients treated with oral contraceptive, whereas patients treated with add-back therapy showed a better quality of life, as assessed with the SF-36 questionnaire, and adverse effects rate than the other two groups.

CONCLUSION(S)

Add-back therapy allows the treatment of women with relapse of endometriosis-associated pain for a longer period, with reduced bone mineral density loss, good control of pain symptoms, and better patient quality of life compared with GnRH analogue alone or oral contraceptive.

Prediction of the change in bone mineral density induced by gonadotropin-releasing hormone agonist treatment for endometriosis

OBJECTIVE

To observe the long-term changes in bone metabolism induced by GnRH agonist (GnRHa) treatment and to determine the factor that affected the change in bone mineral density (BMD).

DESIGN

Prospective observational study.

SETTING

Department of obstetrics and gynecology in university and general hospitals.

PATIENT(S)

Fifty women with endometriosis treated with GnRHa between 1994 and 1996.

INTERVENTION(S)

Leuprolide acetate administered for 24 weeks. Bone mineral density measurement by dual energy x-ray absorptiometry and collection of blood and urine samples were conducted until 12 months of posttreatment.

MAIN OUTCOME MEASURE(S)

Spinal BMD and bone turnover markers.

RESULT(S)

Mean BMD percent changes from pretreatment were -4.9% and -3.4% at 6 months of treatment and at 12 months of posttreatment, respectively. When the patients were divided by the median pretreatment deoxypyridinoline (DP) level, recovery of BMD after GnRHa discontinuation was slower in the Low-DP group than in the High-DP group. A significant positive correlation was found between the pretreatment DP level and the percent change in BMD at 12 months of posttreatment. No significant relation between BMD and the other bone turnover markers was noted.

CONCLUSION(S)

Bone mineral density changes were diverse among patients who were administered GnRHa. The pretreatment DP level may be the predictive factor for GnRHa-induced BMD change.

Treatment of endometriosis and chronic pelvic pain with letrozole and norethindrone acetate: a pilot study

OBJECTIVE

To determine the role of an aromatase inhibitor, letrozole, in the treatment of reproductive-age women with endometriosis and associated chronic pelvic pain.

DESIGN

Phase 2, open-label, nonrandomized proof-of-concept study.

SETTING

Outpatient tertiary-care center.

PATIENT(S)

Ten patients with endometriosis, all previously treated both medically and surgically, with unsatisfactory results.

INTERVENTION(S)

Endometriosis was diagnosed by biopsy and scored from an initial diagnostic laparoscopy performed within 1 month before treatment was begun. Oral administration of letrozole (2.5 mg), the progestin norethindrone acetate (2.5 mg), calcium citrate (1,250 mg), and vitamin D (800 IU) was done daily for 6 months. Within 1-2 months after completion of the treatment, a second-look laparoscopy was performed to score and biopsy endometriosis.

MAIN OUTCOME MEASURE(S)

Changes in American Society for Reproductive Medicine (ASRM) scores for endometriosis, pelvic pain assessed by visual analog scale, serum hormone levels (FSH, LH, E(2), and estrone [E(1)]), and bone density (DEXA scan).

RESULT(S)

No histologically demonstrable endometriosis was present in any patient during the second-look laparoscopy. ASRM and pelvic pain scores decreased significantly in response to treatment. Overall, no significant change in bone density was detected. Gonadotropin levels were not significantly altered by treatment, and although circulating E(2) and E(1) levels were reduced, the decrease was not statistically significant.

CONCLUSION(S)

The combination of letrozole and norethindrone acetate achieved marked reduction of laparoscopically visible and histologically confirmed endometriosis in all 10 patients and significant pain relief in nine out of 10 patients who had not responded previously to currently available treatments. On this basis, letrozole should be a candidate for the medical management of endometriosis.

Overview on the effects of progestins on bone

In view of the fact that fractures are the clinically relevant events, risk factors for fractures are discussed first. Bone mineral density (BMD) appears to be a much less important risk factor for the most severe hip fractures than the risk of falling. No results of experimental studies on hormones and fractures at advanced age are available. An overview of the effects of progestins on bone is given. Effects of progestins on bone have been studied by in vitro experiments using cell lines and by more relevant clinical observations. Prospective studies have been conducted following the use of progestins contained in oral contraceptives, alone or in combination with oestrogens; long-term contraception by injection of depot preparations; so-called "add-back" hormonal therapy attempting to reverse the adverse effects of gonadotropin releasing hormone agonists on bone and after different regimens of hormone replacement therapy (HRT) in postmenopausal women. From the data there are no indications that the various progestins, used in clinical practice, have either a bone-protective or an oestrogen antagonistic activity. Progestins do not add or subtract much of the protective action of oestrogens on the bones.

Medical management of endometriosis-associated pain

In the coming years, basic science research into the mechanisms of endometriosis development and persistence almost certainly will open new avenues for treatment. A wide armamentarium of medical therapies already exists, however. The efficacy of most of these methods in reducing endometriosis-associated pain is well established. The choice of which to use depends largely on patient preference after an appropriate discussion of risks, side effects, and cost. Typically, oral contraceptives and NSAIDs are first-line therapy because of their low cost and mild side effects (Box 6). Because of its greater potential for suppressing endometrial development, consideration should be given to prescribing a low-dose monophasic oral contraceptive continuously. If adequate relief is not obtained or if side effects prove intolerable, consideration should be given to the use of progestins (oral, intramuscular, or IUD) or a GnRH agonist with immediate add-back therapy. Progestins are less expensive, but GnRH agonists with add-back may be better tolerated. If none of these medications proves beneficial or if side effects are too pronounced, then repeat surgery is warranted. The surgery may have analgesic value and serves to reconfirm the diagnosis. Finally, if endometriosis is identified at the time of surgery, then consideration should be given to prescribing medical therapy postoperatively.

Gonadotrophin-releasing hormone analogues for endometriosis: bone mineral density

BACKGROUND

Gonadotrophin-releasing hormone analogues (GnRHas) are generally well tolerated, and are effective in relieving the symptoms of endometriosis (Prentice 2003). Unfortunately the low oestrogen state that they induce is associated with adverse effects including an acceleration in bone mineral density (BMD) loss.

OBJECTIVES

To determine the effect of treatment with gonadotrophin-releasing hormone analogues (GnRHas) on the bone mineral density of women with endometriosis, compared to placebo, no treatment, or other treatments for endometriosis, including GnRHas with add-back therapy.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group's specialised register of controlled trials (23rd October 2002) and the Cochrane Central Register of Controlled Trials (Cochrane Library, issue 4, 2002). We also carried out electronic searches of MEDLINE (1966 - March Week 2 2003) and EMBASE (1980 - March Week 2 2003). We also searched the reference lists of articles and contacted researchers in the field.

SELECTION CRITERIA

Prospective, randomised controlled studies of the use of GnRHas for the treatment of women with endometriosis were considered, where bone density measurements were an end point. The control arm of the studies was either placebo, no treatment, another medical therapy for endometriosis, or GnRHas with add-back therapy.

DATA COLLECTION AND ANALYSIS

Two reviewers (JF and MS) independently assessed trial quality and extracted data. Study authors were contacted for additional information.

MAIN RESULTS

Thirty studies involving 2,391 women were included, however only 15, involving 910 women, could be included in the meta-analysis. The meta-analysis showed that danazol and progesterone + oestrogen add-back are protective of BMD at the lumbar spine both during treatment and for up to six and twelve months after treatment, respectively. Between the groups receiving GnRHa and the groups receiving danazol/gestrinone, there was a significant difference in percentage change of BMD after six months of treatment, the GnRH analogue producing a reduction in BMD from baseline and danazol producing an increase in BMD (SMD -3.43, 95 % CI -3.91 to -2.95). Progesterone only add-back is not protective; after six months of treatment absolute value BMD measurements of the lumbar spine did not differ significantly from the group receiving GnRH analogues (SMD 0.15, 95 % CI -0.21 to 0.52). In the comparison of GnRHa versus GnRHa + HRT add-back, that is oestrogen + progesterone or oestrogen only, there was a significantly bigger BMD loss in the GnRHa only group (SMD -0.49, 95 % CI -0.77 to -0.21). These numbers reflect the absolute value measurements at the lumbar spine after six months of treatment. Due to the small number of studies in the comparison we are unable to conclude whether calcium-regulating agents are protective. No difference was found between low and high dose add-back regimes but again only one study was identified for this comparison. Only one study comparing GnRH analogues with placebo was identified, but the study gave no data. No studies comparing GnRH with the oral contraceptive pill (OCP) or progestagens were identified.

REVIEWER'S CONCLUSIONS

Both danazol and progesterone + oestrogen add-back have been shown to be protective of BMD, while on treatment and up to six and 12 months later, respectively. However, by 24 months of follow-up there was no difference in BMD in those women who had HRT add-back. Studies of danazol versus GnRHa did not report long-term follow-up. The significant side effects associated with danazol limit its use.

Endometriosis: current concepts and therapy

Endometriosis is the growth of endometrial tissue in ectopic locations. The clinical picture is extremely pleiomorphic, which can make the diagnosis difficult. Despite 70 years of theories and experimentation, the cause is not clear, and it is likely that more than one mechanism is at work in most patients. Both medical and surgical treatments are available. In each case, the woman and her physician should formulate a comprehensive treatment plan that addresses the primary complaint as well as the patient's reproductive desires.

Use of GnRH antagonists in the treatment of endometriosis

Endometriosis is an oestrogen-dependent disease that is treatable by oestrogen withdrawal, a therapy that has been effectively provided by the use of a gonadotrophin-releasing hormone (GnRH) agonist. Complete oestrogen withdrawal results in unacceptable side-effects, in particular in accelerated bone density loss. This problem has been effectively overcome with 'add-back therapy' using low-dose oestrogens and progestins in combination with a GnRH agonist to limit these side-effects, while still allowing regression of endometriotic lesions. The aim of this study was to determine the feasibility of using a subcutaneous injection of GnRH antagonist in the treatment of endometriosis. All patients (15/15; 100%) reported a symptom-free period during GnRH antagonist treatment, including mood changes, hot flushes, loss of libido, vaginal dryness and other symptoms. Serum oestradiol oscillated around a mean concentration of 50 pg/ml during therapy. Diagnostic laparoscopy before GnRH antagonist administration showed a mean stage III of disease. Regression occurred in 60% of cases (9/15) and the degree of endometriosis declined to stage II. Sequential administration of the GnRH antagonist cetrorelix (Cetrotide) in a 3 mg dosage once weekly over 8 weeks creates a new opportunity for medical treatment of symptomatic endometriosis. Preserving basic oestrogen production during the course of treatment apparently does not influence regression of disease, and has no major side-effects.

Ovarian endometriosis and peritoneal endometriosis: are they different entities from a fertility perspective?

This review summarizes the recent literature concerning new data on the pathogenesis of peritoneal endometriosis and its natural evolution. Indeed, the main concern in endometriosis is the choice of treatment in cases of infertility problems: medical or surgical. This concern could hypothetically be avoided if endometriosis were considered as a spontaneously regressive phenomenon. The present paper also discusses the risk of recurrence and the results of in-vitro fertilization and embryo transfer in cases of ovarian endometriosis. Whatever type of surgery is performed, the results of in-vitro fertilization and embryo transfer are not impaired, especially if damage to the ovarian cortex is avoided. Further studies are required to determine if oocytes from endometriosis patients are altered and could be responsible for the development of lower quality embryos.