Emerging drugs for endometriosis

Treatment of endometriosis with mifepristone mediated by nanostructured lipid carriers

Mifepristone, a progesterone receptor antagonist, was initially used to terminate early pregnancy. As scientific research advanced, it emerged to be effective in the treatment of various tumors and tumor-like conditions such as endometriosis. Despite the therapeutic potential of mifepristone, its therapeutic effect is still far from ideal because the drug is difficult to dissolve and to accumulate in the target tissue sites. To address this issue, mifepristone-loaded nanostructured lipid carriers (Mif-NLC) were prepared by a simple solvent diffusion method and their anti-endometriosis performance and mechanisms were initially investigated. By optimizing the preparation protocol, we obtained uniform and spheroidal Mif-NLC with an average particle size of 280 nm. The encapsulation rate and drug loading capacity were 64.67% ± 0.15% and 2.7% ± 0.014%, respectively, as measured by UV spectrophotometry. The in vitro release kinetics indicated that mifepristone was released from NLC in a sustained-release manner. Compared with free mifepristone, Mif-NLC exhibited enhanced cellular uptake and inhibition of invasion activity in primary mesenchymal cells of endometriosis. A certain reduction in the size of endometriotic cysts was observed in animals compared to controls. The induction of autophagy via Mif-NLC may serve as the molecular mechanism underlying this effect. Furthermore, observation of uterine structures showed negligible toxic effects. This suggested that mifepristone encapsulated in NLC can improve its bioavailability and anti-endometriosis efficacy, which provided a new strategy for the treatment of endometriosis.

Popularity of endocrine endometriosis drugs and limited alternatives in the present and foreseeable future: A survey among 1420 affected women

OBJECTIVES

Endocrine drugs represent an important cornerstone of endometriosis therapy. Pharmaceutical alternatives with similar efficacy remain out of sight in the near future. Aim of this study is to investigate attitudes and perceptions concerning endocrine therapies among affected women.

STUDY DESIGN

An online survey was distributed via social media in Austria, Germany, and Switzerland. Primary endpoints were satisfaction, attitudes and perceptions towards endocrine endometriosis drugs and secondary outcomes differences regarding demographic variables.

RESULTS

Of 1420 respondents, 63.5 % (n = 901) described their own attitude towards these drugs as rather negative. The most frequently reported unfavorable associations and experiences were sideeffects in general (85.5 %, n = 1181), change in libido (67.5 %, n = 932), hormone cycle disruptions (65.9 %, n = 910), and inefficiency at alleviating symptoms (38.2 %, n = 527). In total, 66.1 % (n = 935) were not satisfied with endocrine drugs for endometriosis. Age ≤ 30 years, living in a large city, and having an academic degree were significantly correlated to a more negative perception of these drugs and greater dissatisfaction with current endocrine endometriosis drugs.

CONCLUSIONS

Among women with endometriosis - and particularly among those aged ≤30 years, being large-city residents, or holding an academic degree - there appears to be a relevant degree of rejection and wariness towards endocrine endometriosis drugs. Given the prevalence of endometriosis and the few pharmaceutical alternatives on the horizon, these data point a growing need for further research and development of non-hormonal drugs for the treatment of endometriosis.

Selective Estrogen-Receptor Modulators and Aromatase Inhibitors: Promising New Medical Therapies for Endometriosis?

Endometriosis is an estrogen-dependent disease and estrogen-related pathways are imbalanced in women with endometriosis. One of the key enzymes in estrogen synthesis is aromatase. Inhibiting this pathway at several points is a promising idea for the treatment of endometriosis. The third generation of aromatase inhibitors is becoming more potent in efficacy, with fewer side effects than previous generations, but cotreatment with other hormones is needed to inhibit ovarian stimulation. Other components that promote estrogen synthesis such as COX-2 can also be potentially targeted. Selective estrogen-receptor modulators could also be interesting in view of their tissue-specific effect. However, all these new drugs are still in an early phase of development. At present, it is too early to conclude that aromatase inhibitors, COX-2 inhibitors or selective estrogen-receptor modulators really present any added value compared with the existing drugs that can be used to achieve hormonal suppression in the medical treatment of endometriosis.

Power over Pain: A Brief Review of Current and Novel Interventions for Endometriosis-Associated Pain

An estimated 10%-15% of women of reproductive age suffer from endometriosis and can be plagued with one or many forms of pain. It is no mystery that endometriosis is an extremely complex disease, with several factors leading to the predominant symptoms of infertility and pain. Although there are currently multiple options available for treating endometriosis-associated pain, none have the ability to completely relieve the symptoms. This review both highlights the current trends in treatment of endometriosis-associated pain and explores some novel options available for therapy directed towards oxidative stress, inflammation and nociceptive mechanisms of pain. A PubMed search was conducted to identify the most recent publications on the topic of pain associated with endometriosis, and further research was performed to clarify the mechanism by which current treatments target pain. Lastly, the authors include a review of pharmacological options at the forefront of endometriosis research. A more comprehensive understanding of the mechanisms behind endometriosis-associated pain will ultimately lead to more effective treatments and improved prognoses for patients.

Cytostasis and morphological changes induced by mifepristone in human metastatic cancer cells involve cytoskeletal filamentous actin reorganization and impairment of cell adhesion dynamics

Background

Changes in cell shape and plasticity in cytoskeletal dynamics are critically involved in cell adhesion, migration, invasion and the overall process of metastasis. Previous work in our laboratory demonstrated that the synthetic steroid mifepristone inhibited the growth of highly metastatic cancer cells, while simultaneously causing striking changes in cellular morphology. Here we assessed whether such morphological alterations developed in response to cytostatic concentrations of mifepristone are reversible or permanent, involve rearrangement of cytoskeletal proteins, and/or affect the adhesive capacity of the cells.

Methods

Cancer cell lines of the ovary (SKOV-3), breast (MDA-MB-231), prostate (LNCaP), and nervous system (U87MG) were exposed to cytostatic concentrations of mifepristone and studied by phase-contrast microscopy. The transient or permanent nature of the cytostasis and morphological changes caused by mifepristone was assessed, as well as the rearrangement of cytoskeletal proteins. De-adhesion and adhesion assays were utilized to determine if mifepristone-arrested and morphologically dysregulated cells had abnormal de-adhesion/adhesion dynamics when compared to vehicle-treated controls.

Results

Mifepristone-treated cells displayed a long, thin, spindle-like shape with boundaries resembling those of loosely adhered cells. Growth arrest and morphology changes caused by mifepristone were reversible in SKOV-3, MDA-MB-231 and U87MG, but not in LNCaP cells that instead became senescent. All cancer cell types exposed to mifepristone displayed greatly increased actin ruffling in association with accelerated de-adhesion from the culture plate, and delayed adhesion capacity to various extracellular matrix components.

Conclusions

Cytostatic concentrations of mifepristone induced alterations in the cellular structure of a panel of aggressive, highly metastatic cancer cells of different tissues of origin. Such changes were associated with re-distribution of actin fibers that mainly form non-adhesive membrane ruffles, leading to dysregulated cellular adhesion capacity.

A novel mifepristone-loaded implant for long-term treatment of endometriosis: in vitro and in vivo studies

The objective of this study was to prepare a novel mifepristone-loaded PCL/Pluronic F68 implant to achieve long-term treatment of endometriosis. PCL/Pluronic F68 compound (90/10, w/w) with viscosity average molecular weight of 65,000 was successfully synthesized. The end-capped Pluronic F68 was incorporated in PCL matrixes as molecular dispersion without forming a copolymer. The mifepristone-loaded implant made of PCL/Pluronic F68 compound was a cylindrical capsule with an outer diameter of 2.5mm and an inner diameter of 2.2mm. The surface of PCL/Pluronic F68 compound appears porous because Pluronic F68 which is water soluble could leach out due to the water phase. Drug loading of 0.75-, 1.5- and 3.0-cm length implants was 3.05+/-0.18, 6.06+/-0.41 and 11.87+/-0.39mg, respectively. A sustained mifepristone release rate without obvious initial burst and later decline over a period of 180d was observed. The cumulative drug release showed a linear relationship with time, indicating that mifepristone release from the implants followed zero-order kinetics (R(2)>0.99). The data showed that the C(max) and AUC(0-inf) were proportional to imlant length and dose, and all groups reached plasma C(max) at about the same time (approximately 7d) and had similar T(1/2) (approximately 150d) and MRT (approximately 220d). There were obvious inhibitory effects on the growth of endometrial explants in Wister rats in a dose-dependent manner after administration of mifepristone-loaded implants with implant length from 1.5 to 9.0cm for 1-3 months. However, mifepristone-loaded implants with implant length of 12.0cm had no better inhibitory effects on the growth of endometrium when compared with the implants with implant length of 9.0cm (P>0.05). In conclusion, subcutaneous implantation of mifepristone-loaded PCL/Pluronic F68 capsules was proven an effective means for long-term treatment of chronic endometriosis.

State-of-the-art of intrauterine contraception

Despite its nearly 100-year history, intrauterine contraception is a modern method even in the 21st century and its development is still going on. The aim of innovations is to optimize the contraceptive efficacy and to suppress as much as possible side effects and unwanted events (e.g. menstrual irregularities, expulsion). It is important that this method be made available to all those who could not resort to it earlier (young women, nulligravidae, nulliparae). Currently three areas are more particularly being investigated: (1) flexible, frameless intrauterine implants, (2) levonorgestrel-releasing intrauterine systems, and (3) metal alloy intrauterine devices. Partly relying on the author's own clinical experience and based on the literature of recent years, this article reviews the present state and possibilities with regard to further development of intrauterine contraceptive devices.

A call for more transparency of registered clinical trials on endometriosis

In response to the pressing need for more efficacious and safer therapeutics for endometriosis, there have been numerous reports in the last decade of positive results from animal and in vitro studies of various compounds as potential therapeutics for endometriosis. A handful of these have undergone phase II/III clinical trials. Since the announcement of the International Committee of Medical Journal Editors that mandated registration as a prerequisite for publication, 57 endometriosis-related clinical trials have been registered at ClinicalTrials.gov, an Internet-based public depository for information on drug studies. Among them, 25 are listed as completed, and 2 as suspended. There are 15 completed phase II/III trials, which evaluated the efficacy of various promising compounds. Yet only three of the 15 trials (20%) have published their results. The remaining 12 (80%) studies so far have not published their findings. We argue that this apparent lack of transparency will actually not benefit the trial sponsors or the public, and will ultimately prove detrimental to research efforts attempting to develop more efficacious and safer therapeutics for endometriosis. Thus we call for more transparency of clinical trials on endometriosis.

Catamenial pneumothorax: a case report and review of the literature

A 39-year-old woman presented with the chief complaint of right-sided chest pressure and shortness of breath with dry cough for 3 days. These symptoms coincided with the onset of her menstrual cycle. Her physical examination was significant for decreased breath sounds at the right lung base. Her chest x-ray showed a moderate sized right pneumothorax extending from the apex to the lung base and a small amount of pleural fluid, findings that were verified by chest CT. The patient was seen by consultants from the pulmonary, obstetrics/gynecology, and thoracic surgery services, who agreed that the clinical diagnosis was catamenial pneumothorax, probably associated with thoracic endometriosis. The patient was discharged on levonorgestrel/ethinyl estradiol tablets, which she opted not to take. Three months later, she had similar symptoms that occurred again at the time of menstruation. Her chest x-ray now showed a 10% right-sided pneumothorax. Catamenial pneumothorax is a rare condition affecting women in their reproductive years. Women with this condition most commonly have right-sided pneumothorax. The proper diagnosis is based on being aware of the existence of this relatively rare condition and relating the symptoms of pneumothorax temporally to the menses.

Peroxisome proliferator-activated receptor-gamma and retinoid X receptor agonists synergistically suppress proliferation of immortalized endometrial stromal cells

OBJECTIVE

To examine whether trichostatin A (TSA), a histone deacetylase inhibitor (HDACI), can induce up-regulation of peroxisome proliferator-activating receptor gamma (PPAR gamma) and to see whether LG100268, a retinoid X receptor (RXR) ligand, can inhibit proliferation of endometriotic cells alone or in synergy with ciglitazone, a PPAR gamma agonist.

DESIGN

One endometrial stromal cell line and two endometriotic cell lines used as a model system: Western blot analysis to determine whether TSA can up-regulate PPAR gamma expression, and MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) proliferation assay to see whether ciglitazone and LG100268 have any antiproliferative effects individually or jointly.

SETTING

Academic.

PATIENT(S)

None.

INTERVENTION(S)

Culture of immortalized endometrial and endometriotic cell lines with TSA, or ciglitazone or LG100268.

MAIN OUTCOME MEASURE(S)

PPAR gamma protein expression levels in cells treated with or without TSA, and number of viable cells treated with or without ciglitazone, LG100268, or both.

RESULT(S)

The TSA treatment resulted in up-regulation of PPAR gamma expression in all cell lines in a dose-dependent fashion. Both ciglitazone and LG100268 inhibited proliferation in a dose-dependent manner, and the antiproliferative effects appeared to be synergistic. In addition, endometriotic cells were more sensitive than endometrial stromal cells to LG100268 treatment.

CONCLUSION(S)

The up-regulation of PPAR gamma induced by TSA indicates that the action of HDACIs also includes the PPAR gamma signaling pathway, suggesting that the activation of PPAR gamma is a desirable way to contain endometriosis phenotypes. The higher sensitivity of endometriotic cells than their endometrial counterpart to LG100268 treatment suggests that the sensitivity differential could be exploited effectively to eradicate unwanted ectopic endometrial tissues while minimizing the collateral damage to the normal endometrial tissues.

Suppression of IL-1β-induced COX-2 expression by trichostatin A (TSA) in human endometrial stromal cells

OBJECTIVE

Over-production of cyclooxygenase-2 (COX-2) plays an important role in the positive feedback loop that leads to proliferation and inflammation in endometriosis. Following our observation that histone deacetylase inhibitors (HDACIs) trichostatin A (TSA) and valproic acid (VPA) can suppress proliferation of endometrial stromal cells, we sought to determine whether TSA suppresses IL-1beta-induced COX-2 expression in endometrial stromal cells.

STUDY DESIGN

In vitro study using a recently established immortalized endometrial stromal cell line. The stromal cells were pretreated with TSA before stimulation with IL-1beta, and COX-2 gene and protein expression was measured by real-time quantitative RT-PCR and Western blot analysis, respectively.

RESULTS

IL-1beta stimulated COX-2 expression in a concentration-dependent manner in endometrial stromal cells. The induced COX-2 gene and protein expression were suppressed by TSA pretreatment.

CONCLUSIONS

TSA suppresses IL-1beta-induced COX-2 gene and protein expression in endometrial stromal cells. This finding, coupled with the findings that TSA and another HDACI, valproic acid, suppress proliferation and induce cell cycle arrest, suggests that HDACIs are a promising class of compound that has therapeutic potential for endometriosis.

Mifepristone inhibits ovarian cancer cell growth in vitro and in vivo

PURPOSE

These studies were designed to determine whether the synthetic steroid mifepristone inhibits ovarian cancer growth in vitro and in vivo and the molecular mechanisms involved.

EXPERIMENTAL DESIGN

The effect of mifepristone on ovarian cancer cell growth in vitro was studied in ovarian cancer cell lines of different genetic backgrounds (SK-OV-3, Caov-3, OV2008, and IGROV-1). In addition, the growth inhibition capacity of mifepristone on ovarian carcinoma xenografts was tested in nude mice.

RESULTS

Mifepristone inhibited ovarian cancer cell proliferation in a dose- and time-dependent manner. The cytostatic effect of mifepristone was confirmed in a clonogenic survival assay and was not linked to loss of viability. Mifepristone blocked DNA synthesis, arrested the cell cycle at the G(1)-S transition, up-regulated cyclin-dependent kinase (cdk) inhibitors p21(cip1)and p27(kip1), down-regulated transcription factor E2F1, decreased expression of the E2F1-regulated genes cdk1 (cdc2) and cyclin A, and modestly decreased cdk2 and cyclin E levels. The abrupt arrest in cell growth induced by mifepristone correlated with reduced cdk2 activity, increased association of cdk2 with p21(cip1) and p27(kip1), increased nuclear localization of the cdk inhibitors, and reduced nuclear abundance of cdk2 and cyclin E. In vivo, mifepristone significantly delayed the growth of ovarian carcinoma xenografts in a dose-dependent manner and without apparent toxic effects for the animals.

CONCLUSIONS

These preclinical studies show that mifepristone is effective as a single agent in vitro and in vivo, inhibiting the growth of human epithelial ovarian cancer cells. Mifepristone markedly reduces cdk2 activity likely due to increased association of cdk2 with the cdk inhibitors p21(cip1) and p27(kip1) and reduced nuclear cdk2/cyclin E complex availability. Acting as a cytostatic agent, mifepristone promises to be of translational significance in ovarian cancer therapeutics.

In vitro and in vivo approaches to study angiogenesis in the pathophysiology and therapy of endometriosis

Endometriosis represents one of the most common gynaecological disorders. According to the implantation theory, angiogenesis is a major prerequisite for the initiation and progression of the disease. Thus, during the last decade, many studies have focused on the mechanisms regulating angiogenesis in endometriotic lesions. For this purpose, sophisticated in vitro and in vivo approaches have been established, which are highlighted in this review. Enzyme-linked immunosorbent assays demonstrate the imbalance of pro- and anti-angiogenic growth factors in isolated peritoneal fluid from endometriosis patients. Histological, immunohistochemical and gene expression analyses of endometriotic tissue provide detailed information on the angio-architecture of endometriotic lesions and the different growth factor expression by various cell populations. Moreover, cell culture systems are useful tools for the identification of hormonal and immunological factors involved in the angiogenic process. Finally, sophisticated in vivo models, such as rodent models of peritoneal endometriosis as well as the chorioallantoic membrane assay and the dorsal skinfold chamber, allow for the detailed analysis of blood vessel development in ectopic endometrium and the efficacy of angiogenesis inhibitors. The findings resulting from all these approaches will help to provide better insights into the pathophysiology of endometriosis and to establish new anti-angiogenic treatment strategies for the future.

Use of the levonorgestrel-releasing intrauterine system in women with endometriosis, chronic pelvic pain and dysmenorrhea

OBJECTIVES

This report is a review of the medical literature on the use of the levonorgestrel-releasing intrauterine system (LNG-IUS) in women with endometriosis, adenomyosis, cyclic pelvic pain and dysmenorrhea.

MATERIAL AND METHODS

A review was carried out using the MEDLINE and EMBASE databases to evaluate the use of LNG-IUS in women with endometriosis and adenomyosis.

RESULTS

Nine studies were identified, only two of which were randomized clinical trials. One compared the insertion of LNG-IUS after surgery with expectant conduct and the other compared the use of the device with a GnRH analogue (GnRH-a). All studies reported an improvement in pelvic pain and dysmenorrhea, and a reduction in menstrual bleeding. One study found an improvement in the staging of the disease at 6 months of use, and the studies that evaluated the use of LNG-IUS in women with adenomyosis reported a reduction in uterine volume. Furthermore, the only study in which women were followed up for 3 years after insertion found improvement in pelvic pain at 12 months of use. However, there was no improvement after that period.

CONCLUSIONS

The use of LNG-IUS is an alternative for the medical treatment of women suffering from endometriosis, adenomyosis, chronic pelvic pain or dysmenorrhea, but experience is limited and long-term studies are necessary to reach definitive conclusions. However, for women who do not wish to become pregnant, this device offers the possibility of at least 5 years of treatment following one single intervention.

Two Unsuccessful Clinical Trials on Endometriosis and a Few Lessons Learned

In 1999, a phase II clinical trial on the use of fulvestrant to treat endometriosis was launched; yet after 7 years there is still no report on its outcome. In 2005, another trial on the use of raloxifene to treat endometriosis was terminated early due to unfavorable outcome. The two apparently unsuccessful clinical trials on endometriosis have taught us a few important lessons. First, we need to understand endometriosis through more basic research. We have also been reminded that human endometriosis trials differ from animal studies; anatomy and physiology are often divergent, and outcome measures are certainly different. Ectopic endometrium can differ significantly from eutopic tissue, and this issue needs to be more thoroughly explored. We believe human cell lines will prove to be an inexpensive and valuable tool for future preliminary evaluation of medical therapies as well as discerning pathophysiologic processes of the disease. Based on our current understanding of endometriosis, some concrete benchmarks can be established for testing or screening potential compounds in vitro. Finally, estrogen receptor modulators are often tissue-, cell-, and context-specific in their actions; they should not be simplistically grouped together nor should extrapolations from one compound to another be undertaken in a cavalier manner.

Subhepatic retroperitoneal endometrioma: report of a case

A 38-year-old woman with a history of pelvic endometriosis was referred to our surgical department for the treatment of a cystic lesion most probably originating from the liver. At the laparotomy a solitary cyst was found in the retroperitoneum, connected to the inferior surface of the liver, and was resected. Histopathological examination of the resected specimen revealed that it was an endometriotic cyst. The occurrence of endometriotic cyst in the upper abdomen is very rare: there are no published reports of an endometriotic cyst in that anatomic location. The literature on this subject is reviewed.

Relationship between adolescent amenorrhea and climacteric osteoporosis

OBJECTIVES

The relationship between climacteric osteoporosis and disturbances in menstrual cycle during adolescence was examined.

METHODS

Seven hundred and seventy-one questionnaires were shared out among women visiting the outpatient department for climacteric complaints for the first time between 2001 and 2004. Questions revealed the age, age at menarche and menopause, the regularity or irregularity of menstrual cycle during adolescence and adult ages. The bone mineral density was examined using the Dual Energy X-ray Absorptiometry (DEXA) method on the lumbar spine.

RESULTS

Six hundred and thirty-five of the 771 questionnaires were suitable for analysis. Osteoporosis was observed in 30.1% of the cases. Age, age at the menarche or at the menopause did not alter in the subgroups with or without osteoporosis. The incidence and severity of osteoporosis were significantly higher in patients reporting secondary amenorrhea during adolescent ages (42.1%; average BMD of the lumbar spine 71.6+/-3.9), as compared to the patients with normal cycle (30.4%; average BMD of the lumbar spine 84.8+/-7.8). No correlation between the occurrence of osteoporosis and the frequency of menstrual cycle during adulthood was observed.

CONCLUSIONS

Secondary amenorrhea during the years of adolescence might play a role in the development of more severe osteoporosis in menopause.

Inhibition of proliferation of endometrial stromal cells by trichostatin A, RU486, CDB-2914, N-acetylcysteine, and ICI 182780

BACKGROUND

All current major medications in treating endometriosis are effective in treating pain, most likely through suppression of proliferation of the implants, yet their effectiveness is relatively short term and they all have many undesirable, and sometimes severe, side effects. There is pressing need for novel, more effective medications in treating endometriosis with less and/or milder side effects.

METHODS

Using a recently established immortalized endometrial stromal cell line, we carried out cell proliferation assays for cells treated with trichostatin A (TSA), RU486, CDB-2914, and N-acetylcysteine, and ICI 182780. Gene expression levels for PR-A, PR-B, AR, Fas and FasL were measured. Protein expression levels for ERalpha, ERbeta, and AR were also measured.

RESULTS

Cell proliferation assay results for NAC, H2O2, CDB, and RU486 were nearly identical or similar to what have been reported based on primary cell cultures or in vivo studies. TSA, CDB, RU486 and NAC all had various antiproliferative effects. TSA had a more potent and longer lasting antiproliferative effect than CDB and NAC, even in the presence of an oxidant, H2O2. Its antiproliferative effect was concentration-dependent. ICI did not have a significant antiproliferative effect. PR-A, PR-B, AR, and FasL expression were all increased as compared with untreated cells.

CONCLUSIONS

The cell line appears to be an adequate model for stromal components of endometriotic implants. That ICI has no inhibitory effect on endometrial proliferation may explain why a phase II clinical trial on its use to treat endometriosis did not advance to later stages. The upregulation of PR-B and AR may be responsible for antiproliferative effects induced by TSA, a histone deacetylase inhibitor (HDACI). HDACIs may be promising therapeutics in treating endometriosis due to their antiproliferative effects as well as the potential to restore gene dysregulation through chromatin remodeling.

Medical management of endometriosis

Current approved medical therapies for endometriosis rely on drugs that suppress ovarian steroids and induce a hypoestrogenic state, which determines the atrophy of the ectopic endometrium. Gonadotropin-releasing hormone analogs such as danazol, progestogens and estrogen-progestin combinations have all proven effective in relieving pain and reducing the extent of endometriotic implants. However, symptoms often recur after discontinuation of therapy and hypoestrogenism-related side effects limit the long-term use of most medications. Recently, knowledge of the pathogenesis of endometriosis, particularly at the molecular level, has grown substantially, providing a rational basis for the development of new drugs with precise targets that may be safely administered over the long term.

Aromatase inhibitors and cyclooxygenase-2 (COX-2) inhibitors in endometriosis: New questions—old answers?

The medical treatment of endometriosis needs to be optimized. Therapeutic management strategies for endometriosis-associated pain or recurrent disease are primarily aimed at downregulating ovarian function or antagonizing the effect of estrogen in ectopic endometrial implants. In this context, basic research is providing important results for the development of new, specific treatment modalities. Aromatase overexpression has recently been detected in endometriotic tissue. Aromatase (p450arom) is responsible for converting C19 androgens into estrogen in several types of human tissue. Aromatase activity causes local estrogen biosynthesis, which, in turn, stimulates prostaglandin E2 production by upregulating cyclooxygenase-2 (COX-2). Thus, a positive feedback cycle develops between the two systems. Another abnormality in endometriosis, the deficient 17beta-hydroxysteroiddehydrogenase type II (17beta-HSD-Type-II) expression, impairs the inactivation of estradiol to estrone. In contrast to the eutopic endometrium, these molecular aberrations increase the amount of local estradiol and prostaglandin E2 in endometriosis. In several human cell lines, prostaglandin and estrogen concentrations are associated with proliferation, migration, angiogenesis, apoptosis resistance and even invasiveness. Consequently, aromatase and COX-2 are thought to be promising new therapeutic targets. Thus, specific aromatase inhibitors (e.g. Letrozol/Femara, Anastrozol/Arimidex or Exemestan/Aromasin) or selective COX-2 inhibitors (e.g. Celecoxib/Celebrex, Rofecoxib/Vioxx, Valdecoxib/Bextra) are of great interest and should be studied in clinical trials in premenopausal woman with endometriosis to expand the spectrum of currently available treatment options.

Randomized clinical trial of a levonorgestrel-releasing intrauterine system and a depot GnRH analogue for the treatment of chronic pelvic pain in women with endometriosis

BACKGROUND

The objective of this multicentre randomized, controlled clinical trial was to compare the efficacy of a levonorgestrel-releasing intrauterine system (LNG-IUS) and a depot-GnRH-analogue in the control of endometriosis-related pain over a period of six months.

METHODS

Eighty-two women, 18 to 40 years of age (mean 30 years), with endometriosis, dysmenorrhoea and/or CPP, were randomized using a computer-generated system of sealed envelopes into either LNG-IUS (n = 39) or GnRH analogue (n = 43) treatment groups at three university centres. Daily scores of endometriosis-associated CPP were evaluated using the Visual Analogue Scale (VAS), daily bleeding score was calculated from bleeding calendars, and improvement in quality of life was evaluated using the Psychological General Well-Being Index Questionnaire (PGWBI). The pain score diary was based on the VAS in which women recorded the occurrence and intensity of pain on a daily basis. A monthly score was calculated from the result of the sum of the daily scores divided by the number of days in each observation period.

RESULTS

CPP decreased significantly from the first month throughout the six months of therapy with both forms of treatment and there was no difference between the groups (P > 0.999). In both treatment groups, women with stage III and IV endometriosis showed a more rapid improvement in the VAS pain score than women with stage I and II of the disease (P < 0.002). LNG-IUS users had a higher bleeding score than GnRH-analogue users at all time points of observation with 34% and 71% of patients in the LNG-IUS and GnRH-analogue groups, respectively, reporting no bleeding during the first treatment month, and 70% and 98% reporting no bleeding during the sixth month. No difference was observed between groups with reference to improvement in quality of life.

CONCLUSIONS

Both, the LNG-IUS and the GnRH-analogue were effective in the treatment of CPP-associated endometriosis, although no differences were observed between the two treatments. Among the additional advantages of the LNG-IUS is the fact that it does not provoke hypoestrogenism and that it requires only one medical intervention for its introduction every 5 years. This device could therefore become the treatment of choice for CPP-associated endometriosis in women who do not wish to conceive.