Letrozole combined with norethisterone acetate compared with norethisterone acetate alone in the treatment of pain symptoms caused by endometriosis

A review of phase II and III drugs for the treatment and management of endometriosis

INTRODUCTION

Endometriosis is an estrogen-dependent disease that gives rise to pelvic pain and infertility. Although estroprogestins and progestins currently stand as the first-line treatments for this condition, demonstrating efficacy in two-thirds of patients, a significant portion of individuals experience only partial relief or symptom recurrence following the cessation of these therapies. The coexistence of superficial, deep endometriosis, and ovarian endometriomas, as three distinct phenotypes with unique pathogenetic and molecular characteristics, may elucidate the current heterogeneous biological response to available therapy.

AREAS COVERED

The objective of this review is to furnish the reader with a comprehensive summary pertaining to phase II-III hormonal treatments for endometriosis.

EXPERT OPINION

Ongoing research endeavors are directed toward the development of novel hormonal options for this benign yet debilitating disease. Among them, oral GnRH antagonists emerge as a noteworthy option, furnishing rapid therapeutic onset without an initial flare-up; these drugs facilitate partial or complete estrogen suppression, and promote prompt ovarian function recovery upon discontinuation, effectively surmounting the limitations associated with previously employed GnRH agonists. Limited evidence supports the use of selective estrogen and progesterone receptor modulators. Consequently, further extensive clinical research is imperative to garner a more profound understanding of innovative targets for novel hormonal options.

Low-dose letrozole - an effective option for women with symptomatic adenomyosis awaiting IVF: a pilot randomized controlled trial

RESEARCH QUESTION

Can low-dose letrozole reduce dysmenorrhoea, menorrhagia and sonographic features in symptomatic women with adenomyosis awaiting IVF?

DESIGN

This was a longitudinal randomized prospective pilot study to explore the effectiveness of low-dose letrozole and compare it with a gonadotropin releasing hormone (GnRH) agonist in reducing dysmenorrhoea, menorrhagia and sonographic features in symptomatic women with adenomyosis awaiting IVF. The women were treated for 3 months, either with the GnRH agonist goserelin 3.6 mg/month (n = 77) or the aromatase inhibitor letrozole 2.5 mg three times weekly (n = 79). Dysmenorrhoea and menorrhagia were evaluated at randomization and followed up monthly using a visual analogue score (VAS) and pictorial blood loss assessment chart (PBAC), respectively. A quantitative scoring method was used to assess the improvement of sonographic features after 3 months of treatment.

RESULTS

Both groups reported a marked improvement in symptoms after 3 months of treatment. In both the letrozole and GnRH agonist groups, VAS and PBAC scores decreased significantly over the 3 months (letrozole: P = 0.0001 and P = 0.0001 for VAS and PBAC, respectively; GnRH agonist: P = 0.0001 and P = 0.0001 for VAS and PBAC, respectively). Participants on letrozole had regular menstruation cycles, while most of the women who received the GnRH agonist were amenorrhoeic, with only four women reporting mild bleeding. Haemoglobin concentrations also improved after both treatments (letrozole P = 0.0001, GnRH agonist P = 0.0001). A quantitative assessment of sonographic features showed significant improvements following both treatments (diffuse adenomyosis of the myometrium: letrozole P = 0.015, GnRH agonist P = 0.039; diffuse adenomyosis of the junctional zone: letrozole P = 0.025, GnRH agonist P = 0.001). Women with adenomyoma also responded well to both therapies (letrozole P = 0.049, GnRH agonist P = 0.024), whereas the letrozole group responded comparatively better in focal adenomyosis when the outer myometrium was involved (letrozole P < 0.001, GnRH agonist P = 0.26). No noticeable side effects were observed in women receiving letrozole therapy. Additionally, letrozole therapy was found to be more cost-effective than GnRH agonist treatment.

CONCLUSIONS

Low-dose letrozole treatment is a low-cost alternative to a GnRH agonist, with comparable effects in improving the symptoms and sonographic features of adenomyosis in women awaiting IVF.

A Systematic Review of Systematic Reviews on the Use of Aromatase Inhibitors for the Treatment of Endometriosis: The Evidence to Date

Endometriosis is a chronic gynecologic condition that affects around 6-10% of reproductive age women. This clinical entity is characterized with pelvic pain, dysmenorrhea, dyspareunia, and infertility which are the most often presenting symptoms. Aromatase P450 is the key enzyme for ovarian estrogen biosynthesis and there is evidence that endometriotic lesions express aromatase and are able to synthesize their own estrogens. Aromatase inhibitors (AIs) are potent drugs that suppress the estrogen synthesis via suppression of aromatase. We performed a systematic review of systematic reviews and narrative reviews on the use of aromatase inhibitors in the medical management of endometriosis. We searched: PubMed (1950-2022), Google Scholar (2004-2022), Cochrane Library (2010-2022) and Researchgate (2010-2022). The search included the following medical subject headings (MeSH) or keywords: "Aromatase Inhibitors" AND "Endometriosis" AND "Systematic reviews" OR "Systematic review" AND "Reviews" OR "Reviews" AND "Endometriosis". The electronic database search yielded initially 12,106 studies from the different databases. Further assessment of the studies resulted in exclusion of (n = 12,015) studies due to duplicates and irrelevance; Finally, 24 studies were selected for inclusion, 5 were Systematic reviews and 19 were Narrative reviews. The 5 systematic reviews were assessed by AMSTAR-2 criteria and were found to have low quality. Narrative reviews were assessed with SANRA criteria and were found to have high-quality aromatase inhibitors are potent drugs that can manage the endometriosis-related symptoms in cases where initial medical management has failed to show positive results. However, their use is limited by the adverse effects that are linked with menopausal symptoms. aromatase inhibitors can be administered as an alternative treatment in patients. Future studies with randomized design are required to reach safer conclusions and further investigation. These studies should define the therapeutic dose, new add-back therapy modalities. Future directions should examine the most-appropriate way of administration and the duration of therapy.

Advances in targeting estrogen synthesis and receptors in patients with endometriosis

INTRODUCTION

Endometriosis is an estrogen-dependent disease on the background of progesterone resistance. Increased estrogen production, low estrogen metabolization, and altered estrogen receptors (ERs) expression contribute to the hyperestrogenic milieu within endometriotic lesions. Since estrogens play a crucial role in the pathogenesis of the disease, inhibition of estrogen production is one of the main targets of available and emerging drugs.

AREAS COVERED

Firstly, we described the molecular alterations responsible for estrogen dependence. Secondly, we reviewed available and emerging treatments that interfere, through central (gonadotropin-releasing hormone analogs (GnRH-a), GnRH antagonists) or local mechanisms (aromatase inhibitors (AIs), inhibitors of steroid sulfatase (STS) and hydroxysteroid dehydrogenase type 1 (17β-HSD1)), with estrogen dependence. Finally, we focused on emerging treatments targeting ERs (selective estrogen receptor modulators (SERMs), estrogen receptors agonists, and antagonists).

EXPERT OPINION

Available treatments interfering with estrogen pathways exert a contraceptive effect, have hypoestrogenic side effects, and cannot prevent or definitively treat the disease. Preclinical and animal studies are focusing on emerging drugs targeting ERs in order to overcome limitations of available treatments. These treatments may represent a promising option, as they may produce a more specific inhibition of disease activity within endometriotic implants, avoiding prolonged hypoestrogenic status and limiting systemic side effects.

Is intracrinology of endometriosis relevant in clinical practice? A systematic review on estrogen metabolism

Endometriosis is a chronic, multifactorial, estrogen-dependent disease. The abnormal endocrine microenvironment of endometriosis lesions is considered a main feature and multiple enzymatic pathways leading to local increased synthesis of estrogens have been identified. However, the relevance of intracrinology in clinical practice is still lacking. Medline, Embase, Scopus database were systematically searched for studies reporting on local estrogens metabolism of endometriotic lesions. The main enzymatic pathways involved in the intracrinology of endometriosis such as aromatase (CYP19A1), 17β-hydroxysteroid dehydrogenase (HSD17B) type 1, type 2 and type 5, steroid sulfatase (STS), estrogen sulfotransferase (SULT1E1) were assessed with a critical perspective on their role in disease endocrine phenotyping, drug resistance and as therapeutic targets. Overall, studies heterogeneity and missing clinical data affect the interpretation of the clinical role of these enzymes. Although the use of some drugs such as aromatase inhibitors has been proposed in clinical practice for two decades, their potential clinical value is still under investigation as well as their modality of administration. A closer look at new, more realistic drug targets is provided and discussed. Altered expression of these key enzymes in the lesions have far reaching implication in the development of new drugs aimed at decreasing local estrogenic activity with a minimal effect on gonadal function; however, given the complexity of the evaluation of the expression of the enzymes, multiple aspects still remains to be clarified.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022311329, identifier CRD42022311329.

Use of aromatase inhibitors in menopausal deep endometriosis: a case report and literature review

We report and review the clinical effectiveness of aromatase inhibitors in a patient with refractory, recurrent and infiltrating endometriosis. We demonstrate excellent clinical, radiological and endoscopic responses after failure of multiple other modalities. Our case and the literature show that single-agent letrozole is capable to treat deep infiltrative endometriosis involving the rectum and the urinary tract. The use of aromatase inhibitor treatment of endometriosis in postmenopausal women makes sense, is safe and is well tolerated. Difficult cases of deep infiltrative endometriosis might require use of combined surgical and medical treatment modalities. Multidisciplinary involvement of the gynecologist, bowel surgeon, urologist and invasive radiologist might be needed. Aromatase inhibitors should be considered to be an integral part of the armamentarium in the management of women with endometriosis, especially in refractory cases that have failed conventional therapeutic modalities.

Letrozole combined with oral contraceptives versus oral contraceptives alone in the treatment of endometriosis-related pain symptoms: a pilot study

BACKGROUND

To compare the efficacy and the tolerability of letrozole combined with oral contraceptives versus oral contraceptives alone in treating endometriosis-related pain.

METHODS

A total of 820 women with endometriosis presented with endometriosis-related pain were enrolled with this study. Patients were randomly treated either with letrozole (2.5 mg/day) combined with oral contraceptives (Desogestrel and Ethinylestradiol Tablets) or oral contraceptives (Desogestrel and Ethinylestradiol Tablets) alone for 6 months. Changes in pain symptoms during treatment and in 1 months after treatment, 6-month follow-up and 12-month follow-up were evaluated. Adverse effects of each treatment protocol were recorded.

RESULTS

At completion of treatment, the intensity of chronic pelvic pain continued to decrease during treatment and at 1-month after treatment it was significantly lower than at 6-month follow-up and baseline level both in LE + oral contraceptives group (Mean ± SD,1.5 ± 1.4) and in oral contraceptives alone group(Mean ± SD,2.9 ± 1.2).The intensity of chronic pelvic pain and deep dyspareunia was significantly decrease at both 1-month after treatment and 6-month follow-up.

CONCLUSIONS

This treatment for endometriosis is a promising new modality that warrants further investigation.

Aromatase inhibitors for the treatment of endometriosis: a systematic review about efficacy, safety and early clinical development

INTRODUCTION

Pharmacotherapy has a key role in endometriosis treatment and management, however, a significant proportion of patients have only intermittent or limited benefits with current treatment options. Therefore, novel therapeutic approaches are necessary.

AREAS COVERED

This systematic review provides an overview of the efficacy and safety of aromatase inhibitors (AIs) as monotherapies and combination therapies for endometriosis. A systematic literature search was performed from January 1990 to April 2020 in the electronic database MEDLINE, EMBASE, The Cochrane Library, and Web of Science.

EXPERT OPINION

Based on the critical role of estrogens and the rate-limiting step in the production of the estrogens represented by the aromatase enzyme, AIs are a potential therapeutic option for women affected by endometriosis. Nevertheless, further research is needed to clarify the efficacy of AIs in this setting. Adverse effects need to be investigated to clarify the preventive role of add-back therapy. On that basis, AIs should be adopted only as second-line therapy in patients who are refractory to standard treatments in the setting of scientific research. Further studies should define best dosages, appropriate add-back therapies, administration routes, treatment length, and which patients may benefit more from AIs.

Advances in the medical management of bowel endometriosis

Endometriosis infiltrating the bowel can be treated medically in accurately selected women not seeking conception and without overt obstructive symptomatology. When the rectosigmoid junction is involved, the probabilities of intestinal symptoms relief, undergoing surgery after treatment failure, and developing bowel obstruction during hormonal treatment are around 70%, 10%, and 1-2%, respectively. When the lesion infiltrates exclusively the mid-rectum, thus in cases of true rectovaginal endometriosis, the probabilities of intestinal symptoms relief and undergoing surgery are about 80% and 3%, respectively. Endometriotic obstructions of the rectal ampulla have not been reported. A rectosigmoidoscopy or colonoscopy should be performed systematically before starting medical therapies, also to rule out malignant tumours arising from the intestinal mucosa. Progestogens are safe, generally effective, well-tolerated, inexpensive, and should be considered as first-line medications for bowel endometriosis. Independently of symptom relief, intestinal lesions should be checked periodically to exclude nodule progression during hormonal treatment.

Progesterone receptor ligands for the treatment of endometriosis: the mechanisms behind therapeutic success and failure

BACKGROUND

Despite intense research, it remains intriguing why hormonal therapies in general and progestins in particular sometimes fail in endometriosis.

OBJECTIVE AND RATIONALE

We review here the action mechanisms of progesterone receptor ligands in endometriosis, identify critical differences between the effects of progestins on normal endometrium and endometriosis and envisage pathways to escape drug resistance and improve the therapeutic response of endometriotic lesions to such treatments.

SEARCH METHODS

We performed a systematic Pubmed search covering articles published since 1958 about the use of progestins, estro-progestins and selective progesterone receptor modulators, to treat endometriosis and its related symptoms. Two reviewers screened the titles and abstracts to select articles for full-text assessment.

OUTCOMES

Progesterone receptor signalling leads to down-regulation of estrogen receptors and restrains local estradiol production through interference with aromatase and 17 beta-hydroxysteroid dehydrogenase type 1. Progestins inhibit cell proliferation, inflammation, neovascularisation and neurogenesis in endometriosis. However, progesterone receptor expression is reduced and disrupted in endometriotic lesions, with predominance of the less active isoform (PRA) over the full-length, active isoform (PRB), due to epigenetic abnormalities affecting the PGR gene transcription. Oxidative stress is another mechanism involved in progesterone resistance in endometriosis. Among the molecular targets of progesterone in the normal endometrium that resist progestin action in endometriotic cells are the nuclear transcription factor FOXO1, matrix metalloproteinases, the transmembrane gap junction protein connexin 43 and paracrine regulators of estradiol metabolism. Compared to other phenotypes, deep endometriosis appears to be more resistant to size regression upon medical treatments. Individual genetic characteristics can affect the bioavailability and pharmacodynamics of hormonal drugs used to treat endometriosis and, hence, explain part of the variability in the therapeutic response.

WIDER IMPLICATIONS

Medical treatment of endometriosis needs urgent innovation, which should start by deeper understanding of the disease core features and diverse phenotypes and idiosyncrasies, while moving from pure hormonal treatments to drug combinations or novel molecules capable of restoring the various homeostatic mechanisms disrupted by endometriotic lesions.

Effects of silymarin, cabergoline and letrozole on rat model of endometriosis

OBJECTIVE

Silymarin as an herbal drug has potent antioxidant effects that could make it a good choice for endometriosis therapy. The aim of the current study was to determine the effects of silymarin as an herbal drug on induced endometrial lesion in rat model of endometriosis.

MATERIALS AND METHODS

A total of 32 mature, female Sprague-Dawley rats were allocated into 4 experimental groups. The duration of study was about 6 months. Endometriosis implants were surgically prepared and autografted into 32 rats. Three weeks after endometriosis induction, animals were randomly allocated into four groups: Group 1 received cabergoline (CAB group); Group 2 received letrozole (LET group); Group 3 received silymarin (SIL group) and Group 4 received no medication (CONT group). Experimental groups were treated for 3 weeks and then were sacrificed for volume and histopathological evaluation of implants and biochemical assessment. Serum and peritoneal levels of vascular endothelial growth factor (VEGF), total antioxidant activity (TAC) and tumor necrosis (TNF)-α were measured.

RESULTS

Mean volume of the implants decreased significantly in silymarin (p < 0.001), letrozole (p < 0.001) and cabergoline (p < 0.001) groups compared to the control. Histopathologic score was significantly lower in silymarin (p: 0.039), letrozole (p: 0.017) and cabergoline (p < 0.001) groups compared to the control. Those receiving silymarin had significantly higher serum TAC compared to control after 21 days of therapy (p < 0.001).

CONCLUSION

Silymarin, Letrozole, and Cabergoline administration resulted in decreased size and histopathologic grade of the induced endometrial lesions in a rat model. Silymarin appears to be a virtual novel therapeutic agent for treatment of endometriosis.

Bowel endometriosis: diagnosis and management

The most common location of extragenital endometriosis is the bowel. Medical treatment may not provide long-term improvement in patients who are symptomatic, and consequently most of these patients may require surgical intervention. Over the past century, surgeons have continued to debate the optimal surgical approach to treating bowel endometriosis, weighing the risks against the benefits. In this expert review we will describe how the recommended surgical approach depends largely on the location of disease, in addition to size and depth of the lesion. For lesions approximately 5-8 cm from the anal verge, we encourage conservative surgical management over resection to decrease the risk of short- and long-term complications.

Management of Chronic Pelvic Pain

The management of chronic pelvic pain poses a significant challenge to both physicians and patients. Patients should be evaluated for both gynecologic and nongynecologic conditions, and >1 source may be identified. Treatment involves medical as well as surgical options, and it is important to set realistic goals with patients. Treatment may not be curative, but should improve the patient's quality of life.

[New medical treatments for painful endometriosis: CNGOF-HAS Endometriosis Guidelines]

OBJECTIVE

The objective of this work is to evaluate the place of new treatments in the management of endometriosis outside the context of infertility.

METHODS

A review of the literature was conducted by consulting Medline data until July 2017.

RESULTS

Dienogest is effective compared to placebo in short term (NP2) and long term (NP4) for the treatment of painful endometriosis. In comparison with GnRH agonists, dienogest is also effective in terms of decreased pain and improved quality of life in non-operated patients (NP2) as well as for recurrence of lesions and symptomatology postoperatively (NP2). Data on GnRH antagonists, selective progesterone receptor modulators as well as selective inhibitors (anti-TNF-α, matrix metalloprotease inhibitors, angiogenesis growth factor inhibitors) are insufficient to provide evidence of interest in clinical practice for the management of painful endometriosis (NP3).

CONCLUSION

Dienogest is recommended as second-line therapy for the management of painful endometriosis (Grade B). Because of lack of evidence, aromatase inhibitors, elagolix, SERM, SPRM and anti-TNF-α are not recommended for the management of painful endometriosis (Grade C).

Shifting from Oral Contraceptives to Norethisterone Acetate, or Vice Versa, because of Drug Intolerance: Does the Change Benefit Women with Endometriosis?

BACKGROUND/AIMS

Oral contraceptives (OC) and norethisterone acetate (NETA) are among first-line medical therapies for symptomatic endometriosis, but their use is sometimes associated with intolerable side effects. We investigated whether shifting from low-dose OC to NETA (2.5 mg/day), or vice versa, improved tolerability.

METHODS

Sixty-seven women willing to discontinue their treatment because of intolerable side effects despite good pain relief, were enrolled in a self-controlled study, and shifted from OC to NETA (n = 35) or from NETA to OC (n = 32). The main study outcome was satisfaction with treatment 12 months after the change. Tolerability, pain symptoms, health-related quality of life, psychological status, and sexual functioning were also evaluated.

RESULTS

After treatment change, good tolerability was reported by 37% of participants who shifted to NETA, and by 52% of those who shifted to OC. At 12-month assessment, 51% of women intolerant to OC were satisfied with NETA, and 65% of those intolerant to NETA were satisfied with OC (intention-to-treat analysis). Other study variables did not vary substantially.

CONCLUSIONS

In selected endometriosis patients, shifting from OC to NETA, or vice versa, because of side effects, improved tolerability. Better results were observed when substituting NETA with OC rather than the other way round.

Is Shifting to a Progestin Worthwhile When Estrogen-Progestins Are Inefficacious for Endometriosis-Associated Pain?

The purpose of this study was to assess the proportion of patients satisfied with their treatment after a change from a low-dose oral contraceptive (OC) to norethisterone acetate (NETA) because of inefficacy of OC on pain symptoms. To this end, prospective, self-controlled study was conducted on 153 women using OC as a treatment for endometriosis and with persistence of one or more moderate or severe pain symptoms. At baseline and during 12 months after a shift from OC to oral NETA, 2.5 mg/d, pelvic pain was measured by means of a 0- to 10-point numerical rating scale and a multidimensional categorical rating scale. Variations in health-related quality of life, psychological status, and sexual function were also evaluated with validated scales. At the end of the study period, participants indicated the degree of satisfaction with their treatment according to a 5-degree scale from very satisfied to very dissatisfied. A total of 28 women dropped out of the study, the main reason was intolerable side effects (n = 15). At 12-month assessment, 70% of participants were very satisfied or satisfied with NETA treatment (intention-to-treat analysis). Statistically significant improvements were observed in health-related quality of life, psychological status, and sexual function. At per-protocol analysis, almost half of the patients (58/125) reported suboptimal drug tolerability. However, complaints were not severe enough to cause dissatisfaction, drug discontinuation, or request for surgery. These encouraging results could be used to counsel women with symptomatic endometriosis not responding to OC and to inform their decisions on modifications of disease management.

Future Directions in Endometriosis Research and Therapeutics

Background

Endometriosis is a disease common among women of reproductive age characterized by pain, anxiety and infertility. Defined as the growth of endometrial tissue in ectopic locations, endometriosis remains an enigmatic disease for which current treatments are less than ideal. Much of these shortcomings to current therapy stem from our incomplete understanding on the pathogenesis of the disease. It is generally accepted that endometriosis is an estrogen-dependent disease and, as such, the majority of treatment approaches aim at reducing estrogen action and/or production. Unfortunately, this approach is not effective in all women with endometriosis and in those women where success is achieved with their use, there is potential for health-comprising side effects.

Objective

The objective of this review is to summarize current approaches for treatment of endometriosis, discuss their limitations and potential reasons for lack of progress towards better therapeutics for this disease.

Results

In this review we summarize the current approaches for treatment of endometriosis, discuss their limitations and potential reasons for lack of progress towards better therapeutics for this disease.

Conclusion

Based upon the current state of knowledge, there is a strong necessity for through assessment at the level of the genome, miRNAome and proteome as well as the importance of integrating clinically-relevant endpoints in future studies which evaluate potential endometriosis therapies in experimental models of endometriosis.

[Medical treatment of endometriosis: Hormonal treatment of pain, impact on evolution and future perspectives]

CONTEXT

Endometriosis is a chronic painful disease, for which hormone therapy is usually offered as a first line option to women not willing to conceive.

OBJECTIVES

To analyse and synthesize the literature, from 2006 onwards, on pain control, and disease evolution in oemn using combined hormonal contraceptives, progestins and GnRH analogs. Data on other current and future treatment perspectives is included as well.

SOURCES

Medline (Pubmed), the Cochrane Library, and endometriosis treatment recommendations published by European Society of Human Reproduction and Embryology (ESHRE), National Institute for health and Care Excellence (NICE), American College of Obstetricians and Gynecologists (ACOG), Royal College of Obstetricians and Gynaecologists (RCOG) and Société des Obstétriciens et Gynécologues du Canada (SOGC).

STUDY SELECTION

Meta-analysis and clinical trials are included.

RESULTS

Study quality is heterogeneous in general. Hormone therapy inconstantly allows pain relief and prevention of endometrioma and rectovaginal wall nodules recurrence. Available molecules and routes of administration as well as risk benefit balance are evaluated. Data on future perspectives are limited to date and do not allow use in routine.

CONCLUSION

Hormonal treatment of endometriosis relies on combined hormonal contraceptives (using different routes of administration), progestins and particularly the levonorgestrel-releasing IUS, and GnRH analogs as a last option, in combination with an add-back therapy. Promising alternatives are currently under preclinical and clinical evaluation.

"Per vaginam" topical use of hormonal drugs in women with symptomatic deep endometriosis: a narrative literature review

PURPOSE

We aim to provide a comprehensive overview of the role of the vagina as a route for drug delivery and absorption, with a particular focus on the use of vaginal hormonal compounds for the treatment of deep infiltrating symptomatic endometriosis.

METHODS

A MEDLINE search through PubMed was performed to identify all published studies in English language on vaginal hormonal treatments for symptomatic endometriosis.

RESULTS

Main advantages of the vaginal route include avoidance of the hepatic-first pass metabolic effect, the possibility of using lower therapeutic dosages, and the reduction of side effects compared with the oral administration. Studies on endometriosis treatment mainly focused on the use of vaginal danazol (n = 6) and the contraceptive vaginal ring (n = 2). One pilot study evaluated the efficacy of vaginal anastrozole in women with rectovaginal endometriosis. Most investigations evaluated the vaginal use of hormonal agents in women with deep infiltrating endometriosis/rectovaginal endometriosis. Overall, a substantial amelioration of pelvic pain symptoms associated with endometriosis was observed, particularly of dysmenorrhea. A significant reduction in rectovaginal endometriotic nodule dimensions measured at ultrasound examination was detected by some but not all authors.

CONCLUSIONS

The vaginal route represents a scarcely explored modality for drug administration. High local hormonal concentrations might achieve a greater effect on endometriotic lesions compared with alternative routes. Future studies should focus on the use of the vagina for delivering target therapies particularly in patients with deeply infiltrating rectovaginal lesions.

What Is Known and Unknown About the Association Between Endometriosis and Sexual Functioning: A Systematic Review of the Literature

It is well known that endometriosis is associated with an increase in the risk of deep dyspareunia, with potential negative effects on global female sexual functioning and couple relationship. The aims of this study were to review the literature on the impact of endometriosis on female sexual functioning and to suggest new avenues for future research and treatment strategies. An electronic database research was performed to identify all the studies on the relation between endometriosis and sexual functioning published in the period 2000 to 2016. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. After the screening process, a total of 9 studies investigating the relation between endometriosis and female sexual functioning were considered. Overall, these studies indicated that around two thirds of women with endometriosis have some form of sexual dysfunction not limited to deep dyspareunia. These findings suggest that the global sexual impact of endometriosis requires further investigation, focusing not only on pain during intercourse but also on psychological and relational dimensions, including partner's sexual functioning. Because sexual functioning is a complex, multidimensional phenomenon, the ideal treatment for endometriosis-related sexual dysfunctions should be conducted by a multidisciplinary team composed of gynecologists, sexologists, and psychologists/psychotherapists.

Committee Opinion No. 663: Aromatase Inhibitors in Gynecologic Practice

Aromatase inhibitors have been used for the treatment of breast cancer, ovulation induction, endometriosis, and other estrogen-modulated conditions. For women with breast cancer, bone mineral density screening is recommended with long-term aromatase inhibitor use because of risk of osteoporosis due to estrogen deficiency. Based on long-term adverse effects and complication safety data, when compared with tamoxifen, aromatase inhibitors are associated with a reduced incidence of thrombosis, endometrial cancer, and vaginal bleeding. For women with polycystic ovary syndrome and a body mass index greater than 30, letrozole should be considered as first-line therapy for ovulation induction because of the increased live birth rate compared with clomiphene citrate. Lifestyle changes that result in weight loss should be strongly encouraged. Aromatase inhibitors are a promising therapeutic option that may be helpful for the management of endometriosis-associated pain in combination therapy with progestins.

Model-Based Dose Selection for Intravaginal Ring Formulations Releasing Anastrozole and Levonorgestrel Intended for the Treatment of Endometriosis Symptoms

Pharmacokinetics (PK) of anastrozole (ATZ) and levonorgestrel (LNG) released from an intravaginal ring (IVR) intended to treat endometriosis symptoms were characterized, and the exposure-response relationship focusing on the development of large ovarian follicle-like structures was investigated by modeling and simulation to support dose selection for further studies. A population PK analysis and simulations were performed for ATZ and LNG based on clinical phase 1 study data from 66 healthy women. A PK/PD model was developed to predict the probability of a maximum follicle size ≥30 mm and the potential contribution of ATZ beside the known LNG effects. Population PK models for ATZ and LNG were established where the interaction of LNG with sex hormone-binding globulin (SHBG) as well as a stimulating effect of estradiol on SHBG were considered. Furthermore, simulations showed that doses of 40 μg/d LNG combined with 300, 600, or 1050 μg/d ATZ reached anticipated exposure levels for both drugs, facilitating selection of ATZ and LNG doses in the phase 2 dose-finding study. The main driver for the effect on maximum follicle size appears to be unbound LNG exposure. A 50% probability of maximum follicle size ≥30 mm was estimated for 40 μg/d LNG based on the exposure-response analysis. ATZ in the dose range investigated does not increase the risk for ovarian cysts as occurs with LNG at a dose that does not inhibit ovulation.

Fetal safety profile of aromatase inhibitors: Animal data

Aromatase inhibitors (AIs) are a class of drugs that act by blocking the production of estrogens from androgens. The current review concentrates on the prenatal developmental toxicity of AIs in experimental models. Available data indicate that AIs may affect pregnancy at human therapeutic or lower doses. The window of vulnerability to AIs is not limited to organogenesis, but also includes the preimplantation stage and fetal periods. Decreased embryo/fetal survival was the prominent treatment-related effect. Morphological anomalies noted in fetuses exposed to AIs included skeletal anomalies, abnormal head morphology, increased ano-genital distance in female fetuses, and minor urinary tract system anomalies. Placental enlargement was consistently reported in rats and non-human primates after maternal treatment with several AIs. In conclusion, data from basic scientific research suggest that low intensity exposure to AIs applied during a wide gestational window can profoundly affect prenatal development.

Continuous Norethisterone Acetate versus Cyclical Drospirenone 3 mg/Ethinyl Estradiol 20 μg for the Management of Primary Dysmenorrhea in Young Adult Women

STUDY OBJECTIVE

To evaluate the efficacy of continuous norethisterone acetate (NET-A), 5 mg (group N) vs cyclical combined oral contraceptive pill (COC) consisting of drospirenone 3 mg/ethinyl estradiol 20 μg pills (group P) in treating dysmenorrhea in young adult women.

DESIGN, SETTING, AND PARTICIPANTS

This prospective, open-label, nonrandomized study included 38 Jordanian patients: 20 patients in group N and 18 patients in group P.

INTERVENTIONS

Continuous NET-A 5 mg daily or cyclical COC.

MAIN OUTCOME MEASURES

Pain scores, adverse effects, analgesic use, school absence, and cost.

RESULTS

Thirty-eight patients used NET-A or COC for 6 months. All participants had almost the same starting levels of visual analogue scale (VAS) scores. Both drugs were similar in suppressing dysmenorrhea at the 3-month follow-up visit; VAS score mean (±SD) in group N and P were 1.30 ± 1.22 and 1.28 ± 0.83 (P = .22), respectively, and after 6 months, with mean VAS scores (±SD) of 1.30 ± 1.22 and 1.28 ± 0.83, respectively (P = .95). The cost of the treatment in the N group was much less than in the P group. Participants in the N group were less likely to use pain killers: 20% and 44% in the N and P groups, respectively (P = .006) in the first month and only 5% and 17% (P = .019) in the N and P groups, respectively, at the 3-month follow-up, and none of them used any analgesics at the 6-month follow-up.

CONCLUSION

A continuous NET-A regimen is a well tolerated, effective, and inexpensive option for dysmenorrhea treatment and was as good as COC.

The direct and indirect costs associated with endometriosis: a systematic literature review

STUDY QUESTION

What is the economic burden of endometriosis?

SUMMARY ANSWER

The identified studies indicate that there is a significant economic burden associated with endometriosis, as observed by both direct and indirect costs.

WHAT IS KNOWN ALREADY

Two previous systematic literature reviews suggested that there were considerable direct costs associated with endometriosis and there was a general lack of measurement of indirect costs.

STUDY DESIGN, SIZE, DURATION

We performed a systematic literature review. MEDLINE and EMBASE databases from 2000 to 2013 were searched. The literature search was limited to human studies of patients with endometriosis. Papers in languages other than English were excluded.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Studies reporting direct or indirect costs among patients with endometriosis were considered for inclusion. Direct costs included inpatient, outpatient, surgery, drug and other healthcare service cost. Indirect costs were related to absenteeism and presenteeism (lost productivity at work).

MAIN RESULTS AND THE ROLE OF CHANCE

After evaluating the 1396 articles in the search results, 12 primary studies that reported direct or indirect costs associated with endometriosis were identified and included in the data extraction. Three of the studies were conducted in the USA, one study each was conducted in Austria, Belgium, Brazil, Canada, Finland, Germany and Italy, and two studies included data from 10 countries. Significant variability was observed in the reviewed studies in methodology, including data source, cost components considered and study perspective. Estimates of total direct costs ranged from $1109 per patient per year in Canada to $12 118 per patient per year in the USA. Indirect costs of endometriosis ranged from $3314 per patient per year in Austria to $15 737 per patient per year in the USA.

LIMITATIONS, REASONS FOR CAUTION

The studies identified in the systematic literature review varied greatly by study methodology as well as by country owing to different healthcare systems and costs of healthcare services, which contributed to large variations in the direct and indirect cost estimates.

WIDER IMPLICATIONS OF THE FINDINGS

A majority of the studies we found were published after the periods covered in the prior systematic literature reviews, which provided substantial contributions to an understanding of the economic burden of endometriosis, especially in the area of indirect costs. The long-term burden of endometriosis following diagnosis is still under-studied, which is a concern given the chronic nature of the disease and the substantial recurrence of endometriosis symptoms.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by AbbVie, which also develops the oral GnRH antagonist elagolix (in collaboration with Neurocrine Biosciences) for the management of endometriosis and uterine fibroids. A.M.S. is an employee of AbbVie and currently owns AbbVie stocks. H.Y., E.X.D. and C.K. are employees of Analysis Group, Inc., which has received consultancy fees from AbbVie. C.W. is a Clinical Professor at the Department Obstetrics and Gynecology at Georgetown University in Washington, DC, USA and has served in a consulting role to AbbVie for this project.

Evaluation of endometriosis-associated pain and influence of conventional treatment: a systematic review

SUMMARY Endometriosis is a chronic gynecological disease characterized by sustained painful symptoms that are responsible for a decline in the quality of life of sufferers. Conventional treatment includes surgical and pharmacological therapy aiming at reducing painful symptoms. This study aimed to evaluate pain levels in women with endometriosis, focusing on the influence of conventional treatment in controlling this variable. To do so, a literature search was conducted in the Medline/Pubmed databases, with 119 scientific articles found. After applying the inclusion and exclusion criteria, 27 were selected for reading and elaboration of this review. Thus, 9 studies evaluated the contribution of surgery, 17 the use of drugs to reduce pain levels in patients with endometriosis and one assessed surgical and medical treatment. The main results of these searches are presented and discussed in this revision. Surgery and the use of drugs provided reduced pain scores in patients with endometriosis but nevertheless exhibit disadvantages, such as risk of recurrence and side effects, respectively. Treatment of endometriosis is, therefore, a challenge for gynecologists and patients, as they must select the best therapeutic approach for this disease. However, improved quality of life in these patients has been obtained with the use of conventional treatment.

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.

Endometriosis: alternative methods of medical treatment

Endometriosis is an inflammatory estrogen-dependent disease defined by the presence of endometrial glands and stroma at extrauterine sites. The main purpose of endometriosis management is alleviating pain associated to the disease. This can be achieved surgically or medically, although in most women a combination of both treatments is required. Long-term medical treatment is usually needed in most women. Unfortunately, in most cases, pain symptoms recur between 6 months and 12 months once treatment is stopped. The authors conducted a literature search for English original articles, related to new medical treatments of endometriosis in humans, including articles published in PubMed, Medline, and the Cochrane Library. Keywords included "endometriosis" matched with "medical treatment", "new treatment", "GnRH antagonists", "Aromatase inhibitors", "selective progesterone receptor modulators", "anti-TNF α", and "anti-angiogenic factors". Hormonal treatments currently available are effective in the relief of pain associated to endometriosis. Among new hormonal drugs, association to aromatase inhibitors could be effective in the treatment of women who do not respond to conventional therapies. GnRH antagonists are expected to be as effective as GnRH agonists, but with easier administration (oral). There is a need to find effective treatments that do not block the ovarian function. For this purpose, antiangiogenic factors could be important components of endometriosis therapy in the future. Upcoming researches and controlled clinical trials should focus on these drugs.