A phase II trial of anastrozole in advanced recurrent or persistent endometrial carcinoma: a Gynecologic Oncology Group study

Translating biological insights into improved management of endometrial cancer

Endometrial cancer (EC) is the most common gynaecological cancer among women in high-income countries, with both incidence and mortality continuing to increase. The complexity of the management of patients with EC has evolved with greater comprehension of the underlying biology and heterogeneity of this disease. With a growing number of novel therapeutic agents available, emerging treatment regimens seem to have the potential to help to address the concerning trends in EC-related mortality. In this Review, we describe the epidemiology, histopathology and molecular classification of EC as well as the role of the new (2023) International Federation of Gynecologists and Obstetricians (FIGO) staging model. Furthermore, we provide an overview of disease management in the first-line and recurrent disease settings. With increasing use of molecular profiling and updates in treatment paradigms, we also summarize new developments in this rapidly changing treatment landscape.

Top advances of the year: Uterine cancer

Endometrial cancer continues to be the only gynecologic malignancy with a rising incidence and mortality, with both regional and global implications. Combination carboplatin and paclitaxel has been the recognized chemotherapy backbone for the treatment of advanced-stage or recurrent disease, with modest clinical outcomes. Over the last year, significant advances were achieved in improving oncologic outcomes by capitalizing on the molecular characterization of this heterogenous disease. These advances include incorporation of immunotherapy, identification of effective hormonal approaches, the evolution of antibody drug conjugates, and utilization of alternate targeted therapies. PLAIN LANGUAGE SUMMARY: The molecular characterization of endometrial cancer has been critical in informing novel treatment strategies. Over the past year, significant gains have been made via the incorporation of immunotherapy, hormonal combinations as well as antibody drug conjugates.

Combined aromatase, CDK4/6 and PI3K blockade using letrozole/abemaciclib/LY3023414 in endometrial cancer

Several lines of preclinical evidence indicate that combining PI3K and CDK4/6 inhibitors may further enhance the efficacy of hormonal therapy by overcoming de novo and acquired resistance to PI3K and CDK4/6 blockade. We evaluated the combination of abemaciclib, letrozole and LY3023414 (an orally available, selective inhibitor of the class I PI3K isoforms and mTORC1/2) in recurrent endometrial cancer (EC). This study was terminated prematurely after 5 patients initiated protocol therapy due to discontinuation of further development of LY3023414. We report our findings from these patients, including one with recurrent endometrioid EC with AKT1, CTNNB1 and ESR1 hotspot mutations who had previously progressed through letrozole/everolimus and achieved a partial response to letrozole/abemaciclib/LY3023414.

Evolving treatment paradigms in metastatic or recurrent low-grade endometrial cancer: When is hormonal-based therapy the preferred option?

Endometrial cancer is the most common gynecologic malignancy in developed countries, with increasing incidence and mortality rates worldwide. While most cases are successfully treated with surgery, first-line treatment options for metastatic or recurrent endometrial cancer involve significant toxicities. Imprecise classification of heterogeneous subgroups further complicates treatment decisions and interpretation of clinical trial results. Recent advances in molecular classification are guiding treatment decisions for metastatic or recurrent endometrial cancers. Integrating molecular characteristics with traditional clinicopathology can both reduce overtreatment or undertreatment and help guide the appropriate choice of therapies and effective design of future studies. Here we discuss the treatment of metastatic or recurrent low-grade endometrioid adenocarcinoma of the uterine corpus, which is distinct from high-grade tumors histologically, molecularly, and in treatment response.

Do Not Forget about Hormonal Therapy for Recurrent Endometrial Cancer: A Review of Options, Updates, and New Combinations

Hormonal therapy has long been a treatment modality for recurrent endometrial cancer. It is appealing for patients with low-grade, slow-growing tumors or in patients for which other treatment types may be too toxic. Hormonal therapy is well tolerated and has response rates ranging from 9 to 33%. Hormonal treatment options take advantage of the estrogen-dependent molecular pathways in endometrial cancers. Current options for hormonal therapies include progesterone therapy (medroxyprogesterone acetate and megestrol acetate) as a single agent or in combination and agents that target the estrogen pathway. Aromatase inhibitors have had modest single-agent activity, but synergistic effects have been found when used in combination with targeted therapy including mTOR inhibitors and cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. Molecular profiling of endometrial cancers has begun to help individualize treatments. This review will report on existing data and ongoing trials investigating novel hormonal therapy agents.

A Phase II, Two-Stage Study of Letrozole and Abemaciclib in Estrogen Receptor-Positive Recurrent Endometrial Cancer

PURPOSE

Estrogen receptor (ER)-positive endometrial cancers (ECs) are characterized by phosphatidylinositol 3-kinase (PI3K) and receptor tyrosine kinase (RTK)/RAS/β-catenin (CTNNB1) pathway alterations in approximately 90% and 80% of cases, respectively. Extensive cross-talk between ER, PI3K, and RTK/RAS/CTNNB1 pathways leads to both ligand-dependent and ligand-independent ER transcriptional activity as well as upregulation of cyclin D1 which, in complex with cyclin-dependent kinases 4 and 6 (CDK4 and CDK6), is a critical regulator of cell cycle progression and a key mediator of resistance to hormonal therapy. We hypothesized that the combination of the aromatase inhibitor letrozole and CDK4/6 inhibitor abemaciclib would demonstrate promising activity in this setting.

METHODS

We conducted a phase II, two-stage study of letrozole/abemaciclib in recurrent ER-positive EC. Eligibility criteria included measurable disease, no limit on prior therapies, and all EC histologies; prior hormonal therapy was allowed. Primary end points were objective response rate by RECIST 1.1 and progression-free survival (PFS) rate at 6 months.

RESULTS

At the data cutoff date (December 03, 2021), 30 patients (28 with endometrioid EC) initiated protocol therapy; 15 (50%) patients had prior hormonal therapy. There were nine total responses (eight confirmed), for an objective response rate of 30% (95% CI, 14.7 to 49.4), all in endometrioid adenocarcinomas. Median PFS was 9.1 months, PFS at 6 months was 55.6% (95% CI, 35.1 to 72), and median duration of response was 7.4 months. Most common ≥ grade 3 treatment-related adverse events were neutropenia (20%) and anemia (17%). Responses were observed regardless of grade, prior hormonal therapy, mismatch repair, and progesterone receptor status. Exploratory tumor profiling revealed several mechanistically relevant candidate predictors of response (CTNNB1, KRAS, and CDKN2A mutations) or absence of response (TP53 mutations), which require independent validation.

CONCLUSION

Letrozole/abemaciclib demonstrated encouraging and durable evidence of activity in recurrent ER positive endometrioid EC.

Novel approaches for treatment of endometrial carcinoma

Endometrial cancer (EC) is common malignancy in women and its incidence is slowly on the rise. Accurate surgical staging, with aggressive cytoreduction when indicated, remains the most critical step in the treatment. Careful pathological evaluation and/or molecular risk stratification guides for proper systemic adjuvant radiotherapy ± chemotherapy. Recurrent and metastatic EC has dismal prognosis and palliative therapies (chemotherapy, hormonal therapy or radiation) forms the backbone of treatment. There is an unmet need of newer therapies to improve survival in such cases. A number of tyrosine kinase inhibitors are currently under evaluation. Recent data on therapeutic targeting of HER2 positive serous EC is exciting. Data on check point inhibitors particularly based on biomarker select population has raised hope for potentially effective treatment for women with high risk endometrial cancer .

The Use of Targeted Agents in the Treatment of Gynecologic Cancers

OPINION STATEMENT

Patients with advanced and recurrent ovarian, uterine, and cervical cancers have limited efficacious treatment options and poor outcomes. The development of agents that target DNA repair mechanisms, angiogenesis, immune checkpoints, and hormone receptor expression provides additional options for these patients. Many available targeted therapies have limited efficacy as single agents, so clinical trials investigating combination therapies as well as continued identification and validation of predictive biomarkers are critical. Many novel small molecule therapies, antibody drug conjugates, and therapeutic vaccines are also in development. This review will focus on recent evidence supporting the use of clinically available targeted therapies for gynecologic cancer.

Pharmacological Treatment of Advanced, Persistent or Metastatic Endometrial Cancer: State of the Art and Perspectives of Clinical Research for the Special Issue "Diagnosis and Management of Endometrial Cancer"

Patients with metastatic or recurrent endometrial cancer (EC) not suitable for surgery and/or radiotherapy are candidates for pharmacological treatment frequently with unsatisfactory clinical outcomes. The purpose of this paper was to review the results obtained with chemotherapy, hormonal therapy, biological agents and immune checkpoint inhibitors in this clinical setting. The combination of carboplatin (CBDCA) + paclitaxel (PTX) is the standard first-line chemotherapy capable of achieving objective response rates (ORRs) of 43-62%, a median progression-free survival (PFS) of 5.3-15 months and a median overall survival (OS) of 13.2-37.0 months, respectively, whereas hormonal therapy is sometimes used in selected patients with slow-growing steroid receptor-positive EC. The combination of endocrine therapy with m-TOR inhibitors or cyclin-dependent kinase 4/6 inhibitors is currently under evaluation. Disappointing ORRs have been associated with epidermal growth factor receptor (EGFR) inhibitors, HER-2 inhibitors and multi-tyrosine kinase inhibitors used as single agents, and clinical trials evaluating the addition of bevacizumab to CBDCA + PTX have reported conflicting results. Immune checkpoint inhibitors, and especially pembrolizumab and dostarlimab, have achieved an objective response in 27-47% of highly pretreated patients with microsatellite instability-high (MSI-H)/mismatch repair (MMR)-deficient (-d) EC. In a recent study, the combination of lenvatinib + pembrolizumab produced a 24-week response rate of 38% in patients with highly pretreated EC, ranging from 64% in patients with MSI-H/MMR-d to 36% in those with microsatellite stable/MMR-proficient tumors. Four trials are currently investigating the addition of immune checkpoint inhibitors to PTX + CBDCA in primary advanced or recurrent EC, and two trials are comparing pembrolizumab + lenvatinib versus either CBDCA + PTX as a first-line treatment of advanced or recurrent EC or versus single-agent chemotherapy in advanced, recurrent or metastatic EC after one prior platinum-based chemotherapy.

Multi-tissue transcriptome-wide association study identifies eight candidate genes and tissue-specific gene expression underlying endometrial cancer susceptibility

Genome-wide association studies (GWAS) have revealed sixteen risk loci for endoemtrial cancer but the identification of candidate susceptibility genes remains challenging. Here, we perform transcriptome-wide association study (TWAS) analyses using the largest endometrial cancer GWAS and gene expression from six relevant tissues, prioritizing eight candidate endometrial cancer susceptibility genes, one of which (EEFSEC) is located at a potentially novel endometrial cancer risk locus. We also show evidence of biologically relevant tissue-specific expression associations for CYP19A1 (adipose), HEY2 (ovary) and SKAP1 (whole blood). A phenome-wide association study demonstrates associations of candidate susceptibility genes with anthropometric, cardiovascular, diabetes, bone health and sex hormone traits that are related to endometrial cancer risk factors. Lastly, analysis of TWAS data highlights candidate compounds for endometrial cancer repurposing. In summary, this study reveals endometrial cancer susceptibility genes, including those with evidence of tissue specificity, providing insights into endometrial cancer aetiology and avenues for therapeutic development.

Pik Fang Kho et al. conduct multi-tissue transcriptome-wide association studies of endometrial cancer risk. Their results identify potential susceptibility genes for endometrial cancer, and provide avenues for the development of future treatments for this disease.

Phase II trial of ribociclib and letrozole in patients with relapsed oestrogen receptor-positive ovarian or endometrial cancers

Objective

We describe a phase II clinical trial of the combination of ribociclib and letrozole for treatment of relapsed oestrogen receptor (ER)-positive ovarian cancer (OC) and endometrial cancer (EC). The primary endpoint was the proportion of patients alive, progression-free survival (PFS), and still on treatment at 12 weeks (PFS12), with 45% or greater considered positive.

Methods

Patients with measurable, relapsed ER-positive OC or EC (platinum-sensitive or resistant) were eligible and treated with 400 mg of oral ribociclib and 2.5 mg of oral letrozole daily. Patient-derived xenografts (PDXs) were created from imaging-guided tumour biopsies.

Results

Forty patients (20 OC and 20 EC) were enrolled. A PFS12 of 55% was observed in the EC cohort and 50% in the OC cohort. A PFS greater or equal to 24 weeks (PFS24) was seen in 20% (4/20) of the OC cohort and 35% (7/20) of the EC cohort. The greatest benefit was seen in low-grade serous OC (LGSOC) (3/3, 100% PFS24) and grades 1 and 2 EC (5/11, 45% PFS24). All three LGSOC patients obtained at least a partial response lasting for over 2 years, with two of the three patients still on treatment. PDX tumour engraftment was feasible in 45% of patients. Positive survival effects of the combination of ribociclib and letrozole were observed in two of three EC PDX models.

Conclusion

Ribociclib and letrozole have promising clinical activity in relapsed ER-positive OC and EC, particularly in LGSOC and relapsed ER-positive grade 1 and 2 EC. Generation of PDX models is feasible with positive survival effects observed in EC models.

Trial registration number

ClinicalTrials.gov registry (NCT02657928).

Tailored Therapy Based on Molecular Characteristics in Endometrial Cancer

Management of endometrial cancer, an adenocarcinoma of the endometrium which occupies most uterine corpus neoplasms, including uterine sarcomas, has been more relevant due to its increasing incidence. Extensive research on tumorigenesis molecular mechanisms and molecular characterization across cancers has brought paradigm shifts in the treatment of various malignant tumors. Endometrial cancer treatment has been traditionally guided according to the disease extent or histology types, while recent studies on molecular features have led to the introduction of targeted agents into clinical use, along with conventional chemotherapeutic agents in patients with recurrent or metastatic disease. Considering the proven efficacy and relatively tolerable toxicities of targeted therapies across malignant tumors, improvement of treatment outcomes is also expected in endometrial cancer by adopting an individualized therapy depending on the specific molecular features. Efficacy assessment of new biological agents is still ongoing based on previous preclinical data on endometrial cancer molecular features. Here, endometrial cancer molecular characterization will be reviewed, and then, we will introduce preclinical data, directing the adoption of new biological agents.

Sex Hormones, Insulin, and Insulin-like Growth Factors in Recurrence of High-Stage Endometrial Cancer

BACKGROUND

The influence of sex hormone and insulin/insulin-like growth factor (IGF) axis signaling on endometrial cancer recurrence is unknown. We evaluated these pathways in a prospective cohort of Gynecologic Oncology Group (GOG)0210 trial endometrial adenocarcinoma patients.

METHODS

Stage II-IV patients (N = 816) were included in this study. Pretreatment specimens were tested for tumor mRNA and protein expression of IGF1, IGF2, IGF-binding proteins (IGFBP)-1 and -3, insulin (IR) and IGF-I receptors (IGF1R), phosphorylated IR/IGF1R (pIGF1R/pIR), and estrogen (ER) and progesterone receptors (PR) using qPCR and IHC. Serum concentrations of insulin, IGF-I, IGFBP-3, estradiol, estrone, and sex hormone binding globulin were measured. HRs and 95% confidence intervals (CI) for progression-free survival were calculated from Cox models adjusting for age, stage, and grade.

RESULTS

Recurrence occurred in 280 (34%) cases during a median of 4.6 years of follow-up. ER positivity (HR, 0.67; 95% CI, 0.47-0.95), IR positivity (HR, 0.53; 95% CI, 0.29-0.98), and circulating IGF-I (highest vs. lowest quartile: HR, 0.66; 95% CI, 0.47-0.92) were inversely associated with recurrence risk. Circulating estradiol (highest vs. lowest tertile: HR, 1.55; 95% CI, 1.02-2.36) and pIGF1R/pIR positivity (HR, 1.40; 95% CI, 1.02-1.92) were associated with increased recurrence risk.

CONCLUSIONS

Circulating estradiol and tumor tissue phosphorylated (activated) IGR1R/IR were independently associated with higher risk of recurrence in patients with endometrial cancer.

IMPACT

This study may inform future clinical trials of endocrine-targeted adjuvant therapies in patients with endometrial cancer that could include baseline assessment of serum and tissue biomarkers of estradiol and insulin signaling pathways.

Endometrial cancer: A society of gynecologic oncology evidence-based review and recommendations, part II

In 2014, the Society of Gynecologic Oncology's Clinical Practice Committee published a clinical update reviewing the treatment of women with endometrial cancer. At that time, there had been significant advances in the diagnosis, work-up, surgical management, and available treatment options allowing for more optimal care of affected women. This manuscript, Part II in a two-part series, includes specific recommendations on treatment of recurrent disease, post treatment surveillance and survivorship, considerations for younger women, and special situations. Part I covered histopathology and molecular pathology, risk factors, presentation and diagnostic approach, surgical approach and adjuvant therapy.

Endometrial Cancer: When Upfront Surgery Is Not an Option

Background and Summary: The management of endometrial cancer, in an ever-older population with considerable comorbidity, remains a challenge for gynecological and radiation oncologists. Key Message: The present paper reviews literature data on treatment options for endometrial cancer patients unfit for surgery.

Progress in endometrial cancer: Contributions of the former Gynecologic Oncology Group

For over forty years, the Gynecologic Oncology Group drove progress in treating endometrial cancer. The first decades of investigation began with a meticulous prospective, surgicopathologic staging study that was the platform for development of all subsequent trials. The resultant statistical model of low risk, intermediate risk, and high-risk groups of patients led to trials where therapeutic modalities were best targeted at disease spread. A clear role for chemotherapy was established. It was realized that greater advances might be achieved with the advent of newer anti-neoplastic agents and these agents were subjected to extensive phase II testing. These agents later were integrated into comparison trials for advanced endometrial cancer. Multimodality therapy continues to show promise. Hormonal therapy was thoroughly investigated and led to combination hormonal therapy trials. Newer agents, including biologics are under active study, as well as the potential contribution of modern imaging techniques. Finally, GOG0210 established a repository of clinical specimens with detailed clinical and epidemiologic data from patients with surgically staged endometrial carcinoma. This should provide for a much greater understanding of molecular characteristics associated with risk of endometrial cancer recurrence, clinical and histological characteristics, and epidemiologic factors.

Patient-derived explants, xenografts and organoids: 3-dimensional patient-relevant pre-clinical models in endometrial cancer

The majority of endometrial cancers are detected early with a favourable prognosis. However, for patients with advanced disease, chemotherapy response rates and overall survival remains poor. The endometrial cancer population is typically elderly with multiple co-morbidities and aggressive cytotoxic therapy may be hazardous. Therefore, there is an urgent need to define optimal treatment strategies for advanced and recurrent disease and personalise therapy based on individual tumour and patient characteristics. Three-dimensional (3D) models that preserve the tumour microenvironment and tumour-stromal interactions are increasingly important for translational research with the advent of immunotherapy and molecularly targeted agents. 3D patient-relevant pre-clinical models in endometrial cancer include spheroids, patient-derived organoids, microfluidic systems, patient-derived xenografts and patient-derived explants. Here we present a review of available 3D modelling systems in endometrial cancers, highlighting their current use, advantages, disadvantages and applications to translational research with a focus on the power of the patient-derived explant platform.

Fluorene-9-bisphenol inhibits epithelial-mesenchymal transition of human endometrial cancer Ishikawa cells by repressing TGF-β signaling pathway

Fluorene-9-bisphenol (BHPF), a new derivative of bisphenol A (BPA), has been introduced for treatment with estrogen-related tumors, such as endometrial cancer. This study investigated the potential mechanism underlying the action of BHPF against endometrial cancer in vitro. We used the cell counting kit-8 (CCK8) method on Ishikawa cells to screen sub-lethal doses of BHPF and established the optimal concentration at which BHPF influenced the proliferation of Ishikawa cells. Effect of BHPF on cell migration and invasion was investigated by cell scratch assay and transwell assay, respectively. Expression levels of epithelial-mesenchymal transition (EMT)-related proteins were detected by Western blot analysis. BHPF was found to inhibit the proliferation of Ishikawa cells, whose migration and invasion abilities were also reduced. Western blot indicated that BHPF can significantly inhibit the EMT process of Ishikawa cells by blocking transforming growth factor-β (TGF-β) signaling pathway. This is the first report of the effect of BHPF on the biological behavior of endometrial cancer cells and its inhibition of endometrial cancer progression by repressing both endometrial cell proliferation and epithelial-mesenchymal transition, hence suggesting it as a novel anti-cancer drug. Graphical abstract Schematic representation of the molecular basis underlying BHPF treatment. BHPF repressed the EMT process by regulating EMT-related genes, such as E-cadherin, N-cadherin, and vimentin as well as the TGF-β signaling pathway-related genes, including p-Smad2/3 and slug, in a BHPF-dependent manner.

Systemic therapy for the treatment of endometrial cancer

Introduction: Endometrial cancer (EC) is one of the most frequent gynecological cancers worldwide. The gold standard treatment of EC is most certainly surgery and may very well be the only therapy in the early stages of disease. To improve outcomes in non-early EC, adjuvant therapy is often employed but this is not standardized. Adjuvant options can include radiotherapy, chemotherapy or a combination of both. Adjuvant chemotherapy could be indicated in high-risk stage I and II or advanced stage EC. Several clinical trials are ongoing in an attempt to define the optimal adjuvant treatment. Furthermore, chemotherapy is the front-line therapy in advanced unresectable, metastatic or recurrent endometrial cancer. Areas covered: Herein, the authors review the first-line chemotherapy for the treatment of endometrial cancer and provide their expert perspectives on these therapies. Expert opinion: Chemotherapy is fundamental in advanced/recurrent EC. Further evidence is needed to characterize the role of adjuvant chemotherapy. Future studies should consider genomic and molecular heterogeneities to identify even more efficient tailored therapies.

Phase 2 study of anastrozole in recurrent estrogen (ER)/progesterone (PR) positive endometrial cancer: The PARAGON trial - ANZGOG 0903

BACKGROUND

The clinical benefit rate with aromatase inhibitors and the impact of treatment on quality of life (QOL) in endometrial cancer is unclear. We report the results of a phase 2 trial of anastrozole in endometrial cancer.

METHODS

Investigator initiated single-arm, open label trial of anastrozole, 1 mg/d in patients with ER and/or PR positive hormonal therapy naive metastatic endometrial cancer. Patients were treated until progressive disease (PD) or unacceptable toxicity. The primary end-point was clinical benefit (response + stable disease) at 3 months. Secondary endpoints include progression-free survival (PFS), quality of life (QOL) and toxicity.

RESULTS

Clinical benefit rate in 82 evaluable patients at 3 months was 44% (95% CI: 34-55%) with a best response by RECIST of partial response in 6 pts. (7%; 95% CI: 3-15%). The median PFS was 3.2 months (95% CI: 2.8-5.4). Median duration of clinical benefit was 5.6 months (95% CI: 3.0-13.7). Treatment was well tolerated. Patients who had clinical benefit at 3 months reported clinically significant improvements in several QOL domains compared to those with PD; this was evident by 2 months including improvements in: emotional functioning (39 vs 6%: p = 0.002), cognitive functioning (45 vs 19%: p = 0.021), fatigue (47 vs 19%: p = 0.015) and global health status (42 vs 9%: p = 0.003).

CONCLUSION

Although the objective response rate to anastrozole was relatively low, clinical benefit was observed in 44% of patients with ER/PR positive metastatic endometrial cancer and associated with an improvement in QOL.

Local estrogen metabolism (intracrinology) in endometrial cancer: A systematic review

Endometrial cancer (EC) is the most common malignancy of the female gynaecological tract and increased exposure to estrogens is a risk factor. EC cells are able to produce estrogens locally using precursors like, among others, adrenal steroids present in the serum. This is referred to as local estrogen metabolism (or intracrinology) and consists of a complex network of multiple enzymes. Particular relevant to the final generation of active estrogens in endometrial cells are: steroid sulfatase (STS), estrogen sulfotransferase (SULT1E1), aromatase (CYP19A1), 17β-hydroxysteroid dehydrogenase (HSD17B) type 1 and type 2. During the last decades, a plethora of studies explored the level of these enzymes in EC but contrasting data were reported, which generated vigorous debate and controversies. Several reviews attempted at clarifying some of the debated issues, but published reviews are based on investigator-defined bibliography selection and not on systematic analysis. Therefore, we performed a systematic review of the literature reporting about the level of STS, SULT1E1, CYP19A1, HSD17B1 and HSD17B2 in EC. Additional intracrine enzymes and networks (e.g., HSD17Bs other than types 1 and 2, aldo-keto reductases, progesterone and androgen metabolism) were non-systematically reviewed as well.

Anti-estrogen Treatment in Endometrial Cancer: A Systematic Review

Introduction: Hormonal therapy in endometrial cancer (EC) is used for patients who wish to preserve fertility and for patients with advanced or recurrent disease in a palliative setting. First line hormonal therapy consists of treatment with progestins, which has a response rate of 25% in an unselected population. Treatment with anti-estrogens is an alternative hormonal therapy option, but there is limited data on the effect and side-effects of anti-estrogens in EC. Therefore, we performed a systematic review to investigate the response rate and toxicity of anti-estrogenic therapy in patients with endometrial cancer.

Methods: A systematic search in electronic databases was performed to identify studies on selective estrogen receptor modulators (SERM) and down-regulators (SERD) and aromatase inhibitors that reported on response rates (RR) among EC patients. Outcome in estrogen receptor (ER) positive and negative disease was assessed independently.

Results: Sixteen studies on advanced stage and recurrent EC were included. Ten studies investigated anti-estrogen monotherapy and seven investigated a combination of anti-estrogenic drugs with either progestin or targeted treatment. Due to heterogeneity in patient population, no meta-analysis was performed. The median age of the patients in the included studies ranged from 61 to 71 years and the proportion of low grade tumors ranged from 38 to 80%. The RR for tamoxifen ranged from 10 to 53%, for other SERMs and SERDs 9–31%, for aromatase inhibitors from 8 to 9%, for combined tamoxifen/progestin treatment 19–58%, for combined chemo- and hormonal therapy 43% and for combination of anti-estrogenic treatment with mammalian target of rapamycin (mTOR) inhibitors 14–31%. Toxicity consisted mainly of nausea and thrombotic events and was higher in combination therapy of chemotherapy and hormonal therapy and hormonal therapy and mTOR inhibitors compared to other therapies.

Conclusion: Tamoxifen or a combination of tamoxifen and progestin should be the preferred choice when selecting second line hormonal treatment because the RRs are similar to first line progestin treatment and the toxicity is low. The response can be optimized by selecting patients with endometrioid tumors and positive estrogen receptor status, which should be based on a pretreatment biopsy.

Lenvatinib plus pembrolizumab in patients with advanced endometrial cancer: an interim analysis of a multicentre, open-label, single-arm, phase 2 trial

BACKGROUND

Lenvatinib is a multikinase inhibitor of VEGFR1, VEGFR2, and VEGFR3, and other receptor tyrosine kinases. Pembrolizumab, an antibody targeting PD-1, has moderate efficacy in biomarker-unselected endometrial cancer. We aimed to assess the combination of lenvatinib plus pembrolizumab in patients with advanced endometrial carcinoma, after establishing the maximum tolerated dose in a phase 1b study.

METHODS

In this open-label, single-arm, phase 2 study done at 11 centres in the USA, eligible patients were aged 18 years or older and had metastatic endometrial cancer (unselected for microsatellite instability or PD-L1), had an Eastern Cooperative Oncology Group performance status of 0 or 1, had received no more than two previous systemic therapies, had measurable disease according to the immune-related Response Evaluation Criteria In Solid Tumors (irRECIST), and had a life expectancy of 12 weeks or longer. Patients received 20 mg oral lenvatinib daily plus 200 mg intravenous pembrolizumab every 3 weeks. Treatment continued until disease progression, development of unacceptable toxic effects, or withdrawal of consent. The primary endpoint of this interim analysis was the proportion of patients with an objective response at week 24 as assessed by investigators according to irRECIST in the per-protocol population. This trial is registered with ClinicalTrials.gov, number NCT02501096.

FINDINGS

Between Sept 10, 2015, and July 24, 2017, 54 patients were enrolled, 53 of whom were included in the analysis. At the cutoff date for anti-tumour activity data (Dec 15, 2017), median study follow-up was 13·3 months (IQR 6·7-20·1). 21 (39·6% [95% CI 26·5-54·0]) patients had an objective response at week 24. Serious treatment-related adverse events occurred in 16 (30%) patients, and one treatment-related death was reported (intracranial haemorrhage). The most frequently reported any-grade treatment-related adverse events were hypertension (31 [58%]), fatigue (29 [55%]), diarrhoea (27 [51%]), and hypothyroidism (25 [47%]). The most common grade 3 treatment-related adverse events were hypertension (18 [34%]) and diarrhoea (four [8%]). No grade 4 treatment-related adverse events were reported. Five (9%) patients discontinued study treatment because of treatment-related adverse events.

INTERPRETATION

Lenvatinib plus pembrolizumab showed anti-tumour activity in patients with advanced recurrent endometrial cancer with a safety profile that was similar to those previously reported for lenvatinib and pembrolizumab monotherapies, apart from an increased frequency of hypothyroidism. Lenvatinib plus pembrolizumab could represent a new potential treatment option for this patient population, and is being investigated in a randomised phase 3 study.

FUNDING

Eisai and Merck.

Estrogen Signaling in Endometrial Cancer: a Key Oncogenic Pathway with Several Open Questions

Endometrial cancer is the most common gynecological cancer in the developed world, and it is one of the few cancer types that is becoming more prevalent and leading to more deaths in the USA each year. The majority of endometrial tumors are considered to be hormonally driven, where estrogen signaling through estrogen receptor α (ER) acts as an oncogenic signal. The major risk factors and some treatment options for endometrial cancer patients emphasize a key role for estrogen signaling in the disease. Despite the strong connections between estrogen signaling and endometrial cancer, important molecular aspects of ER function remain poorly understood; however, progress is being made in our understanding of estrogen signaling in endometrial cancer. Here, we discuss the evidence for the importance of estrogen signaling in endometrial cancer, details of the endometrial cancer-specific actions of ER, and open questions surrounding estrogen signaling in endometrial cancer.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

Development of an Image-Guided Orthotopic Xenograft Mouse Model of Endometrial Cancer with Controllable Estrogen Exposure

Endometrial cancer (EC) is the most common gynaecological malignancy in Western society and the majority of cases are estrogen dependent. While endocrine drugs proved to be of insufficient therapeutic value in the past, recent clinical research shows promising results by using combinational regimens and pre-clinical studies and identified potential novel endocrine targets. Relevant pre-clinical models can accelerate research in this area. In the present study we describe an orthotopic and estrogen dependent xenograft mouse model of EC. Tumours were induced in one uterine horn of female athymic nude mice using the well-differentiated human endometrial adenocarcinoma Ishikawa cell line—modified to express the luciferase gene for bioluminescence imaging (BLI). BLI and contrast-enhanced computed-tomograph (CE-CT) were used to measure non-invasive tumour growth. Controlled estrogen exposure was achieved by the use of MedRod implants releasing 1.5 μg/d of 17β-estradiol (E2) in ovariectomized mice. Stable E2 serum concentration was demonstrated by LC-MS/MS. Induced tumours were E2 responsive as increased tumour growth was observed in the presence of E2 but not placebo, assessed by BLI, CE-CT, and tumour weight at sacrifice. Metastatic spread was assessed macroscopically by BLI and histology and was seen in the peritoneal cavity, in the lymphovascular space, and in the thoracic cavity. In conclusion, we developed an orthotopic xenograft mouse model of EC that exhibits the most relevant features of human disease, regarding metastatic spread and estrogen dependency. This model offers an easy to manipulate estrogen dosage (by simply adjusting the MedRod implant length), image-guided monitoring of tumour growth, and objectively measurable endpoints (including tumour weight). This is an excellent in vivo tool to further explore endocrine drug regimens and novel endocrine drug targets for EC.

Management Strategies for Recurrent Endometrial Cancer

INTRODUCTION

Endometrial cancer is the most common gynecologic malignancy in the developed world, and its incidence is increasing. Mortality from this cancer has not improved in recent decades and is primarily driven by high-grade carcinomas that are more likely to present at an advanced stage and ultimately are more likely to recur. The prognosis for recurrent endometrial cancer is poor, especially for the 50% of these women that present with extrapelvic disease recurrence. As a standard of care, recurrent disease has been treated with platinum-based chemotherapy; however, new therapies are emerging as we identify drivers of proliferation and metastasis at the cellular and molecular levels. Areas Covered: We review currently available data for the management of recurrent endometrial cancer, with a focus on systemic treatment of recurrent disease. We discuss the available evidence for first-line, second-line, and subsequent systemic therapy and discuss emerging therapeutic targets including their biologic plausibility and early clinical data. Expert Commentary: Endometrial cancer, though prevalent, remains underfunded and understudied. Recurrent and metastatic disease remains difficult to treat, and prospective randomized data are limited. Our ability to reduce mortality due to this cancer is dependent on identifying new and effective therapeutic strategies for recurrent disease.

The Use of Endometrial Cancer Patient-Derived Organoid Culture for Drug Sensitivity Testing Is Feasible

Supplemental digital content is available in the text.

Objective

Patient-derived organoids (PDOs), used in multiple tumor types, have allowed evaluation of tumor characteristics from individual patients. This study aimed to assess the feasibility of applying PDO in vitro culture for endocrine-based and drug sensitivity testing in endometrial cancer.

Methods

Endometrial cancer cells were enzymatically dissociated from tumors retrieved from fresh hysterectomy specimens and cultured within basement membrane extract in serum-free medium. An organoid growth assay was developed to assess the inhibitory effects of a variety of drugs including endocrine treatments. Organoid cultures were also prepared for histological and immunohistochemical comparison to the tumors of origin.

Results

Fifteen endometrial cancer specimens were successfully cultured as PDOs. Small spherical structures formed within 24 hours, and many continued to grow to larger, denser organoids, providing the basis for an organoid growth assay. The STAT3 transcription factor inhibitor, BBI608 (Napabucasin), strongly inhibited growth in almost all PDO cultures, suggesting that stemness programing is involved in organoid formation and/or growth. Inhibition by different growth factor receptor tyrosine kinase inhibitors was observed in several PDO specimens. Four cultures were inhibited by fulvestrant, implying the importance of estrogen-receptor signaling in some PDO cultures. Organoids closely resembled their tumors of origin in both histomorphology and immunohistochemical expression.

Conclusions

The use of endometrial cancer PDO cultures for development of drug sensitivity testing for individual patient tumors is feasible. The potential value of the PDO model for clinical decision making will require clinical trial evaluation.

Aromatase inhibitor use during ovarian stimulation suppresses growth of uterine endometrial cancer in xenograft mouse model

STUDY QUESTION

Could aromatase inhibitors (AI) be used to reduce risks of uterine endometrial cancer growth or recurrence during ovarian stimulation?

SUMMARY ANSWER

In a xenograft mouse model of endometrial cancer, concomitant AI administration suppressed the growth of endometrial cancer during ovarian stimulation.

WHAT IS KNOWN ALREADY

Recurrence and mortality rates of estrogen receptor-positive early breast cancer are reduced by long-term AI administration. Concomitant AI use for ovarian stimulation in patients with breast cancer is recommended for reducing estrogen-related potential risks. However, the efficacy of concomitant AI use for estrogen receptor-positive endometrial cancer have not been demonstrated conclusively by clinical or experimental animal studies.

STUDY DESIGN, SIZE, DURATION

Forty nude mice xenografted with uterine endometrial cancer cells were allocated to four groups. Group 1: no ovarian stimulation (control). Group 2: ovarian stimulation. Group 3: AI administration + ovarian stimulation. Group 4: ovariectomy and ovarian stimulation. Tumor growth was evaluated during the 6-week treatment period.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ishikawa 3-H-12 uterine endometrial cancer cells (estrogen and progesterone receptors-positive) were transplanted into 6-week-old BALB/cSlc-nu/nu nude mice, followed by interventions 2 weeks later.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to ovarian stimulation alone (Group 2), significant suppressions of tumor growth were observed in other three groups (Groups 1, 3 and 4, all at P < 0.05) and correlated with estrogen levels. AI administration had no apparent impact on embryo development.

LIMITATIONS, REASONS FOR CAUTION

In this study, we examined the growth of endometrial cancer tumors using one endometrial cancer cell line. Clinical endometrial cancer or hyperplasia cells can have diverse origins and AI may not be effective against other cancer cell types.

WIDER IMPLICATIONS OF THE FINDINGS

Concomitant AI use may provide a chance for safer childbirth by for patients with endometrial cancer or hyperplasia.

STUDY FUNDING/CONPETING INTEREST(S)

This study was supported by the Graduate Student Aid from the St. Marianna University School of Medicine. The authors declare no competing interests.

A role for G-protein coupled estrogen receptor (GPER) in estrogen-induced carcinogenesis: Dysregulated glandular homeostasis, survival and metastasis

Mechanisms of carcinogenesis by estrogen center on its mitogenic and genotoxic potential on tumor target cells. These models suggest that estrogen receptor (ER) signaling promotes expansion of the transformed population and that subsequent accumulation of somatic mutations that drive cancer progression occur via metabolic activation of cathecol estrogens or by epigenetic mechanisms. Recent findings that GPER is linked to obesity, vascular pathology and immunosuppression, key events in the development of metabolic syndrome and intra-tissular estrogen synthesis, provides an alternate view of estrogen-induced carcinogenesis. Consistent with this concept, GPER is directly associated with clinicopathological indices that predict cancer progression and poor survival in breast and gynecological cancers. Moreover, GPER manifests cell biological responses and a microenvironment conducive for tumor development and cancer progression, regulating cellular responses associated with glandular homeostasis and survival, invading surrounding tissue and attracting a vascular supply. Thus, the cellular actions attributed to GPER fit well with the known molecular mechanisms of G-protein coupled receptors, GPCRs, namely, their ability to transactivate integrins and EGF receptors and alter the interaction between glandular epithelia and their extracellular environment, affecting epithelial-to-mesenchymal transition (EMT) and allowing for tumor cell survival and dissemination. This perspective reviews the molecular and cellular responses manifested by GPER and evaluates its contribution to female reproductive cancers as diseases that progress as a result of dysregulated glandular homeostasis resulting in chronic inflammation and metastasis. This review is organized in sections as follows: I) a brief synopsis of the current state of knowledge regarding estrogen-induced carcinogenesis, II) a review of evidence from clinical and animal-based studies that support a role for GPER in cancer progression, and III) a mechanistic framework describing how GPER-mediated estrogen action may influence the tumor and its microenvironment.

A Phase 2, Randomized, Open-Label Study of Irosustat Versus Megestrol Acetate in Advanced Endometrial Cancer

OBJECTIVE

Advanced/metastatic or recurrent endometrial cancer has a poor prognosis. Malignant endometrial tissue has high steroid sulphatase (STS) activity. The aim of this study was to evaluate STS as a therapeutic target in patients with endometrial cancer.

METHODS

This was a phase 2, multicenter, international, open-label, randomized (1:1), 2-arm study of the STS inhibitor oral irosustat 40 mg/d versus oral megestrol acetate 160 mg/d in women with advanced/metastatic or recurrent estrogen receptor-positive endometrial cancer. The primary end point was the proportion of patients without progression or death 6 months after start of treatment. Secondary end points included progression-free survival, time to progression, overall survival, and safety.

RESULTS

Seventy-one patients were treated (36 with irosustat, 35 with megestrol acetate). The study was prematurely stopped after futility analysis. Overall, 36.1% and 54.1% of patients receiving irosustat or megestrol acetate had not progressed or died at 6 months, respectively. There were no statistically significant differences between irosustat and megestrol acetate in response and overall survival rates. Irosustat patients had a median progression-free survival of 16 weeks (90% confidence interval, 9.0-31.4) versus 40 weeks (90% confidence interval, 16.3-64.0) in megestrol acetate patients. Treatment-related adverse events occurred in 20 (55.6%) and 13 (37.1%) patients receiving irosustat or megestrol, respectively. Most adverse events in both groups were grade 1 or 2.

CONCLUSIONS

Although irosustat monotherapy did not attain a level of activity sufficient for further development in patients with advanced/recurrent endometrial cancer, this study confirms the activity of hormonal treatment (megestrol acetate) for this indication.

Blocking 17β-hydroxysteroid dehydrogenase type 1 in endometrial cancer: a potential novel endocrine therapeutic approach

The enzyme type 1 17β-hydroxysteroid dehydrogenase (17β-HSD-1), responsible for generating active 17β-estradiol (E2) from low-active estrone (E1), is overexpressed in endometrial cancer (EC), thus implicating an increased intra-tissue generation of E2 in this estrogen-dependent condition. In this study, we explored the possibility of inhibiting 17β-HSD-1 and impairing the generation of E2 from E1 in EC using in vitro, in vivo, and ex vivo models. We generated EC cell lines derived from the well-differentiated endometrial adenocarcinoma Ishikawa cell line and expressing levels of 17β-HSD-1 similar to human tissues. In these cells, HPLC analysis showed that 17β-HSD-1 activity could be blocked by a specific 17β-HSD-1 inhibitor. In vitro, E1 administration elicited colony formation similar to E2, and this was impaired by 17β-HSD-1 inhibition. In vivo, tumors grafted on the chicken chorioallantoic membrane (CAM) demonstrated that E1 upregulated the expression of the estrogen responsive cyclin A similar to E2, which was impaired by 17β-HSD-1 inhibition. Neither in vitro nor in vivo effects of E1 were observed using 17β-HSD-1-negative cells (negative control). Using a patient cohort of 52 primary ECs, we demonstrated the presence of 17β-HSD-1 enzyme activity (ex vivo in tumor tissues, as measured by HPLC), which was inhibited by over 90% in more than 45% of ECs using the 17β-HSD-1 inhibitor. Since drug treatment is generally indicated for metastatic/recurrent and not primary tumor, we next demonstrated the mRNA expression of the potential drug target, 17β-HSD-1, in metastatic lesions using a second cohort of 37 EC patients. In conclusion, 17β-HSD-1 inhibition efficiently blocks the generation of E2 from E1 using various EC models. Further preclinical investigations and 17β-HSD-1 inhibitor development to make candidate compounds suitable for the first human studies are awaited. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

[Systemic therapy for advanced endometrial cancer]

Endometrial cancer has generally a good prognosis when diagnosed at an early stage, but remains incurable at an advanced stage (recurrent or metastatic) with only few therapeutic options. Hormonal therapy is the treatment of choice in case of slow progressive disease with a tumor expressing hormonal receptors due to its favorable safety profile. Taxanes, anthracyclines and platinum compounds are the most active chemotherapy agents with greater response rates when combined, though at the price of a significant toxicity. Targeted therapies based on a better understanding of tumor biology are being evaluated with some promising results. A good knowledge of patients' comorbidities, and exact histologic characteristics of the tumor (type, grade, hormonal receptor expression, and MSI status) for a well adapted therapeutic decision.

Moving forward with actionable therapeutic targets and opportunities in endometrial cancer: NCI clinical trials planning meeting report on identifying key genes and molecular pathways for targeted endometrial cancer trials

The incidence and mortality rates from endometrial cancer are increasing. There have been no new drugs approved for the treatment of endometrial cancer in decades. The National Cancer Institute, Gynecologic Cancer Steering Committee identified the integration of molecular and/or histologic stratification into endometrial cancer management as a top strategic priority. Based on this, they convened a group of experts to review the molecular data in this disease. Here we report on the actionable opportunities and therapeutic directions identified for incorporation into future clinical trials.

ACR Appropriateness Criteria® Management of Recurrent Endometrial Cancer

OBJECTIVES

In women with endometrial carcinoma (EC), tumor recurrences tend to occur in the 2- to 3-year period following surgical staging. Management of disease recurrence in EC poses significant challenges. These patients represent a heterogenous group where histologic subtypes, previous adjuvant management, interval since completion of adjuvant therapy, and size and site(s) of disease recurrence all have important implications on salvage therapies and prognosis. No randomized controlled trials have been published to determine optimal management in this group of patients. An expert panel was convened to reach consensus on the most appropriate management options in this group of patients.

METHODS

The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

RESULTS

Five clinical variants were developed to address common scenarios in the management of women with recurrent EC. Group members reached consensus on the appropriateness of specific evaluation and treatment approaches with numerical ratings.

CONCLUSIONS

In combining available medical literature and expert opinions, this manuscript may serve as an aid for other practitioners in the appropriate management of women with recurrent EC.

The Association of CYP19A1 Variation with Circulating Estradiol and Aromatase Inhibitor Outcome: Can CYP19A1 Variants Be Used to Predict Treatment Efficacy?

After menopause, estradiol is primarily synthesized in peripheral tissues by the enzyme aromatase, encoded by CYP19A1. CYP19A1 variation associates with circulating estradiol in postmenopausal women and this variation is best represented by the intronic variant rs727479. This variation appears to have pleiotropic effects as it also associates with endometrial cancer risk. Indeed, estradiol plays an important role in the development of breast and endometrial cancer. Aromatase inhibitor (AI) drugs are used in the treatment of both diseases, however, response rates for AIs are low and there is currently no way to identify breast or endometrial cancer patients who are more likely to receive a clinical benefit. Multiple studies have proposed that genetic variation in CYP19A1 will have effects on AI efficacy: eight candidate variant studies of sample size greater than 50 describe associations between CYP19A1 variation and the outcome of patients treated with AIs. Nominally significant associations with patient outcome were reported for several variants, including rs727479. However, only an association between rs4646 and time to progression was replicated in an independent study. Moreover, rs4646 is also the only variant that has an association with patient outcome that passes a multiple testing threshold and this variant is in linkage disequilibrium with rs727479, supporting the hypothesis that associations with patient outcome may be driven through the effects on circulating estradiol. Despite this preliminary evidence, well phenotyped and comprehensively genotyped patient sets need to be studied before conclusions can be drawn about the effects of CYP19A1 variation on AI efficacy.

BGCS uterine cancer guidelines: Recommendations for practice

The British Gynaecological Cancer Society has issued the first Endometrial (Uterine) Cancer guidelines as recommendation for practice for the UK.

Chemoresistance and targeted therapies in ovarian and endometrial cancers

Gynecological cancers are known for being very aggressive at their advanced stages. Indeed, the survival rate of both ovarian and endometrial cancers is very low when diagnosed lately and the success rate of current chemotherapy regimens is not very efficient. One of the main reasons for this low success rate is the acquired chemoresistance of these cancers during their progression. The mechanisms responsible for this acquired chemoresistance are numerous, including efflux pumps, repair mechanisms, survival pathways (PI3K/AKT, MAPK, EGFR, mTOR, estrogen signaling) and tumor suppressors (P53 and Par-4). To overcome these resistances, a new type of therapy has emerged named targeted therapy. The principle of targeted therapy is simple, taking advantage of changes acquired in malignant cancer cells (receptors, proteins, mechanisms) by using compounds specifically targeting these, thus limiting their action on healthy cells. Targeted therapies are emerging and many clinical trials targeting these pathways, frequently involved in chemoresistance, have been tested on gynecological cancers. Despite some targets being less efficient than expected as mono-therapies, the combination of compounds seems to be the promising avenue. For instance, we demonstrate using ChIP-seq analysis that estrogen downregulate tumor suppressor Par-4 in hormone-dependent cells by directly binding to its DNA regulatory elements and inhibiting estrogen signaling could reinstate Par-4 apoptosis-inducing abilities. This review will focus on the chemoresistance mechanisms and the clinical trials of targeted therapies associated with these, specifically for endometrial and ovarian cancers.

Phase II study of the PI3K inhibitor BKM120 in patients with advanced or recurrent endometrial carcinoma: a stratified type I-type II study from the GINECO group

Backround:

Patients with metastatic endometrial carcinoma have a poor prognosis and PIK3CA mutations and amplifications are common in these cancers. This study evaluated the efficacy and safety of the pure PI3K inhibitor BKM120 in advanced or recurrent endometrial carcinoma.

Methods:

This phase II, multicentre, single-arm, double strata (histological low grade (LG) or high grade (HG)) open-label study enrolled patients with histologically confirmed advanced or recurrent endometrial carcinoma who had received not more than one prior chemotherapy regimen. Patients received initially BKM120 100 mg tablets once daily. Primary end points were proportion of patients free of progression at 2 months (HG strata) or at 3 months (LG strata), objective response rate (ORR), and safety.

Results:

A total of 40 patients were enrolled, of whom 16 patients had received BKM120 at 100 mg. Because of high toxicities (cutaneous rash (54%), depressive events (47%), and anxiety (40%), the IDMC has proposed to stop recruitment at 100 mg and to continue the clinical trial with a lower dose of 60 mg per day. In addition, 24 patients (median age 67 years old) were newly enrolled (14 in the LG strata and 10 in the HG strata). Rate of nonprogression at 2 months in the HG strata was 70% and at 3 months was 60% in the LG strata. Median progression-free survival (PFS) for all patients is 4.5 months (CI 95% 2.8–6.1), and the median PFS for LG strata is 8.3 months compared with 3.8 months for the HG strata. No response was reported. At 60 mg per day, the most commonly reported treatment-related adverse events (AEs) were hyperglycaemia (58%), cognitive (31%), digestive (28%), hepatic liver functions (26%), and rash (23%). The most commonly reported treatment-related grade ⩾3 AEs were HTA (17%), hyperglycaemia (17%), and increased alanine aminotransferase (24%). Five patients (21%) stopped BKM120 for toxicity.

Conclusions:

The BKM120 was associated with an unfavourable safety profile and minimal antitumour activity in monotherapy in advanced or recurrent endometrial carcinoma. The clinical trial was stopped before end of recruitment for toxicity.

Clinical Behavior and Treatment of Endometrial Cancer

Endometrial cancer is the most common gynecologic malignancy diagnosed in women in the developed nations. It affects a disproportionate number of reproductive-aged women. While the overall prognosis is good compared to other cancers affecting women, the pathogenesis and clinical behavior of endometrial cancer are heterogeneous. The risk factors associated with the type I and type II endometrial cancers and their pathogenesis will be discussed, as well as the evaluation and primary treatment of women with endometrial cancer. The chapter will also focus on risk stratification for recurrence after surgery and role of adjuvant treatments. Finally, the treatment of recurrent endometrial cancer will be presented.

Hormones and endometrial carcinogenesis

Endometrial cancer (EC) is the commonest gynaecological cancer in the Western World with an alarmingly increasing incidence related to longevity and obesity. Ovarian hormones regulate normal human endometrial cell proliferation, regeneration and function therefore are implicated in endometrial carcinogenesis directly or via influencing other hormones and metabolic pathways. Although the role of unopposed oestrogen in the pathogenesis of EC has received considerable attention, the emerging role of other hormones in this process, such as androgens and gonadotropin-releasing hormones (GnRH) is less well recognised. This review aims to consolidate the current knowledge of the involvement of the three main endogenous ovarian hormones (oestrogens, progesterone and androgens) as well as the other hormones in endometrial carcinogenesis, to identify important avenues for future research.

Chemotherapy for Endometrial Cancer in Adjuvant and Advanced Disease Settings

: Level I evidence exists for use of adjuvant chemotherapy in stage IIIC endometrial cancer (positive lymph nodes), although results of randomized trials have varied. Chemotherapy is also often recommended for high-risk subsets of stage I disease, such as serous carcinomas, although prospective trial data to validate this practice are lacking. Carboplatin plus paclitaxel is the current standard regimen, based on extrapolation of data from the metastatic setting. Several clinical trials have compared adjuvant pelvic radiotherapy alone to a combination of radiotherapy and chemotherapy with mixed results. One of the largest of these trials, Postoperative Radiation Therapy in Endometrial Carcinoma 3 (PORTEC-3), has completed accrual and is awaiting data maturation. Metastatic disease is not curable. For tumors of low-grade endometrioid histology with a prolonged time to recurrence, endocrine therapy with a progestin-based regimen is appropriate. Chemotherapy will be used in most other cases, and the standard first-line regimen is carboplatin and paclitaxel. Few chemotherapy agents have been shown to produce meaningful response rates in the second-line setting. Molecularly targeted therapies such as mTOR inhibitors and antiangiogenic agents including bevacizumab have been studied but their role in the armamentarium remains uncertain.

IMPLICATIONS FOR PRACTICE

Following surgical resection and staging for endometrial cancer, adjuvant chemotherapy with carboplatin and paclitaxel can be administered to patients with a high risk for recurrence. This includes patients with stage IIIC disease with positive lymph nodes, and high-risk subsets of stage I disease such as serous carcinomas. In the metastatic setting, endocrine therapy can be considered, particularly for patients with lower-grade disease and a prolonged time to recurrence. Combined therapy with carboplatin and paclitaxel is the standard of care used for front-line chemotherapy. Antiangiogenic agents are clearly active, but how they should be integrated into treatment is not yet determined. Immunotherapy is a promising direction for patients with mismatch repair-deficient or polymerase ε-mutated tumors.