Clinical activity of durvalumab for patients with advanced mismatch repair-deficient and repair-proficient endometrial cancer. A nonrandomized phase 2 clinical trial

Role of Genomic and Molecular Biology in the Modulation of the Treatment of Endometrial Cancer: Narrative Review and Perspectives

Endometrial cancer (EC) is one of the most common gynecological malignancies in Western countries. Traditionally, loco-reginal dissemination and histological characteristics are the main prognostic factors. Nowadays, molecular and genomic profiling showed exciting results in terms of prognostication. According to the data provided by The Cancer Genome Atlas and other studies, molecular and genomic profiling might be useful in identifying patients al low, intermediate, and high risk of recurrence. However, data regarding the therapeutic value are scant. Several prospective studies are ongoing to identify the most appropriate adjuvant strategy in EC patients, especially for those with positive nodes and low volume disease. The molecular classification has offered the possibility to improve the risk stratification and management of EC. The aim of this review is to focus on the evolution of molecular classification in EC and its impact on the research approach and on clinical management. Molecular and genomic profiling might be useful to tailor the most appropriate adjuvant strategies in apparent early-stage EC.

Treatment patterns and real-world clinical outcomes in patients with advanced endometrial cancer who are microsatellite instability (MSI)-high or are mismatch repair deficient (dMMR) in the United States

OBJECTIVES

Microsatellite instability-high (MSI-H) and deficient DNA mismatch repair (dMMR) status have emerged as actionable biomarkers for advanced endometrial cancer (aEC). The objective of this study was to assess clinical outcomes and treatment patterns among MSI-H/dMMR aEC patients who had disease progression following prior systemic therapy (FPST) in the US.

METHODS

Endometrial Cancer Health Outcomes (ECHO) was a retrospective, medical chart review study of patients with MSI-H/dMMR aEC who had disease progression between 07/01/2016 and 12/31/2018 FPST and were not candidates for curative surgery. Data on patient demographics, clinical and treatment characteristics, and clinical outcomes were collected. Kaplan-Meier analyses were performed to estimate real-world progression-free survival (rwPFS) and overall survival (OS), stratified by drug class.

RESULTS

A total of 124 eligible patients who initiated second-line chemotherapy ± bevacizumab or immunotherapy were included. Mean age was 61.4 years at aEC diagnosis and 86.3% of patients were stage IIIB-IV. Median rwPFS and OS were 4.0 months (95% CI: 2.0-9.0) and 7.0 months (95% CI: 5.0-18.0), respectively, among 21 patients who received chemotherapy ± bevacizumab, and 29.0 months (95% CI: 18.0-NE) and not reached (95% CI: 30.0-NA), respectively, among 103 patients who received immunotherapy. Most patients (n = 92) received pembrolizumab; among these patients, rwPFS and OS were 29.0 months (95% CI: 18.0-NE) and 30 months (95% CI: 30.0-NA), respectively.

CONCLUSIONS

Real-world evidence suggests that pembrolizumab monotherapy provides considerable clinical benefits and has become the standard of care for MSI-H/dMMR aEC patients FPST who are not candidates for curative surgery in real-world settings.

Current Evidence-Based Systemic Therapy for Advanced and Recurrent Endometrial Cancer

Endometrial cancer (EC) is the most common gynecologic malignancy, with worldwide increasing incidence and disease-associated mortality. Although most patients with EC are diagnosed with early-stage disease, systemic treatment options for patients with advanced or recurrent EC have historically been limited. EC-focused clinical trials and the ensuing therapeutic landscape have expanded since The Cancer Genome Atlas (TCGA) identified 4 distinct EC subgroups associated with differential survival. This endeavor revolutionized our understanding of the genomic characterization of EC as well as molecular drivers of this heterogeneous malignancy, leading to precision oncology approaches to therapeutics and advancement in treatment options. This review describes the current status of and recent advancements in therapeutic options for patients with advanced and recurrent EC. The NCCN Guidelines for Uterine Neoplasms provide detailed recommendations regarding the diagnosis, workup, and management of EC.

The role of immunotherapy in advanced and recurrent MMR deficient and proficient endometrial carcinoma

Endometrial cancer is the most common gynecological disease in developed countries. Although it is considered an indolent disease, advanced and recurrent endometrial carcinomas are characterized by poor prognosis. In the metastatic setting, after the failure of first-line platinum-based chemotherapy, patients have limited therapeutic options. However, endometrial cancer should not be considered as a single entity but as a group of heterogeneous diseases with specific genomic, molecular, and biological features by suggested the analysis of The Cancer Genome Atlas (TCGA). Accumulating data highlighted the effectiveness and safety of the adoption of immune checkpoint inhibitors (ICIs) for several types of solid tumors. In particular, immunotherapy showed promising results in MSI-H/dMMR solid tumors. Endometrial cancer is not an exception. Endometrial cancer has the highest prevalence of MSI across human cancer types, and approximately 30% of primary endometrial cancers are MSI-H/dMMR and 13% to 30% of recurrent endometrial cancers are MSI-H/dMMR. The preliminary results of the KEYNOTE-158, the Australian NCT03015129 and the GARNET trial strongly supported the adoption of ICIs as monotherapy in patients with advanced or recurrent endometrial cancer, after the failure of first-line treatments. Unfortunately, those impressive results are not achieved in patients with MMR proficient disease. Hence, other combinations were tested. In particular, the adoption of ICIs plus tyrosine kinase inhibitors (TKI) showed very compelling results. Recently, the updated results of the KEYNOTE-775 showed that pembrolizumab plus lenvatinib led to significantly longer progression-free and overall survival than chemotherapy among patients with advanced endometrial cancer, irrespective of MMR status. After EMA approval, pembrolizumab plus lenvatinib represents the new standard second-line treatment in endometrial cancer patients, regardless MMR status. Further studies are investigating the role of ICIs and TKIs in the first line and are testing new combinations (e.g. ICIs plus PARP inhibitors).

Refining adjuvant treatment in endometrial cancer based on molecular features: the RAINBO clinical trial program

BACKGROUND

The endometrial cancer molecular classification has been integrated into the 2020 World Health Organization (WHO) diagnostic classification and European treatment guidelines, and provides direction towards more effective and less toxic adjuvant treatment strategies for women with endometrial cancer.

PRIMARY OBJECTIVES

The RAINBO program of clinical trials will investigate four molecular class-directed adjuvant treatment strategies following surgical resection to either increase cure rates through the addition of novel targeted therapies or safely reduce toxicity and improve quality of life through treatment de-escalation.

STUDY HYPOTHESIS

Molecular-directed adjuvant treatment strategies will improve clinical outcomes and reduce toxicity of unwarranted therapies in women with endometrial cancer. The overarching and translational research RAINBO program will advance knowledge of predictive and prognostic (bio)markers that will improve prognostication and treatment allocation.

TRIAL DESIGN

The RAINBO program is a platform of four international clinical trials and an overarching research program. The randomized phase III p53abn-RED trial for women with invasive stage I-III p53abn endometrial cancer compares adjuvant chemoradiation followed by olaparib for 2 years with adjuvant chemoradiation alone. The randomized phase III MMRd-GREEN trial for women with stage II (with lymphovascular space invasion (LVSI)) or stage III mismatch repair-deficient (MMRd) endometrial cancer compares adjuvant radiotherapy with concurrent and adjuvant durvalumab for 1 year to radiotherapy alone. The randomized phase III NSMP-ORANGE trial is a treatment de-escalation trial for women with estrogen receptor positive stage II (with LVSI) or stage III no specific molecular profile (NSMP) endometrial cancer comparing radiotherapy followed by progestin for 2 years to adjuvant chemoradiation. The POLEmut-BLUE trial is a phase II trial in which the safety of de-escalation of adjuvant therapy is investigated for women with stage I-III POLEmut endometrial cancer: no adjuvant therapy for lower-risk disease and no adjuvant therapy or radiotherapy alone for higher-risk disease. The overarching RAINBO program will combine data and tumor material of all participants to perform translational research and evaluate molecular class-based adjuvant therapy in terms of efficacy, toxicity, quality of life, and cost-utility.

MAJOR INCLUSION/EXCLUSION CRITERIA

Inclusion criteria include a histologically confirmed diagnosis of endometrial cancer treated by hysterectomy and bilateral salpingo-oophorectomy with or without lymphadenectomy or sentinel lymph node biopsy, with no macroscopic residual disease after surgery and no distant metastases, and molecular classification according to the WHO 2020 algorithm.

PRIMARY ENDPOINTS

Recurrence-free survival at 3 years in the p53abn-RED, MMRd-GREEN, and NSMP-ORANGE trials and pelvic recurrence at 3 years in the POLEmut-BLUE trial.

SAMPLE SIZE

The p53abn-RED trial will include 554 patients, the MMRd-GREEN trial 316, the NSMP-ORANGE trial 600, and the POLEmut-BLUE trial 145 (120 for lower-risk disease and approximately 25 for higher-risk disease). The overarching research program will pool the four sub-trials resulting in a total sample size of around 1600.

ESTIMATED DATES FOR COMPLETING ACCRUAL AND PRESENTING RESULTS

The four clinical trials will have different completion dates; main results are expected from 2028.

TRIAL REGISTRATION NUMBER

The RAINBO program is registered at clinicaltrials.gov (NCT05255653).

Therapeutic Potential of Targeting Transforming Growth Factor-beta (TGF-β) and Programmed Death-ligand 1 (PD-L1) in Pancreatic Cancer

Pancreatic cancer (PC) is one the most lethal malignancies worldwide affecting around half a million individuals each year. The treatment of PC is relatively difficult due to the difficulty in making an early diagnosis. Transforming growth factor-beta (TGF-β) is a multifunctional factor acting as both a tumor promoter in early cancer stages and a tumor suppressor in advanced disease. Programmed death-ligand 1 (PD-L1) is a ligand of programmed death-1 (PD-1), an immune checkpoint receptor, allowing tumor cells to avoid elimination by immune cells. Recently, targeting the TGF-β signaling and PD-L1 pathways has emerged as a strategy for cancer therapy. In this review, we have summarized the current knowledge regarding these pathways and their contribution to tumor development with a focus on PC. Moreover, we have reviewed the role of TGF-β and PD-L1 blockade in the treatment of various cancer types, including PC, and discussed the clinical trials evaluating TGF-β and PD-L1 antagonists in PC patients.

Results of PD-L1 Analysis of Women Treated with Durvalumab in Advanced Endometrial Carcinoma (PHAEDRA)

Women with advanced endometrial carcinoma (EC) with mismatch repair (MMR) deficiency have improved outcomes when treated with immune checkpoint inhibitors; however, additional biomarkers are needed to identify women most likely to respond. Scores for programmed death ligand 1 (PD-L1), immunohistochemical staining of tumor (TC+), immune cells (IC+) and presence of tumor-associated immune cells (ICP) on MMR deficient (n = 34) and proficient (n = 33) EC from women treated with durvalumab in the PHAEDRA trial (ANZGOG1601/CTC0144) (trial registration number ACTRN12617000106336, prospectively registered 19 January 2017) are reported and correlated with outcome. Receiver operating characteristic (ROC) analyses and area under the ROC curve were used to determine optimal cutpoints. Performance was compared with median cutpoints and two algorithms; a novel algorithm derived from optimal cutpoints (TC+ ≥ 1 or ICP ≥ 10 or IC+ ≥ 35) and the Ventana urothelial carcinoma (UC) algorithm (either TC+ ≥ 25, ICP > 1 and IC+ ≥ 25 or ICP = 1 and IC+ = 100). The cutpoint ICP ≥ 10 had highest sensitivity (53%) and specificity (82%), being prognostic for progression-free survival (PFS) (p = 0.01), while the optimal cutpoints algorithm was associated with overall survival (p = 0.02); these results were not significant after adjusting for MMR status. The optimal cutpoints algorithm identified non-responders (p = 0.02) with high sensitivity (88%) and negative predictive value (92%), remaining significant after adjustment for MMR. Although MMR status had the strongest association with response, further work to determine the significance of ICP ≥ 10 and the novel optimal cutpoint algorithm is needed.

Predicting immunotherapy outcomes in patients with MSI tumors using NLR and CT global tumor volume

BACKGROUND

Anti-PD-(L)1 treatment is indicated for patients with mismatch repair-deficient (MMRD) tumors, regardless of tumor origin. However, the response rate is highly heterogeneous across MMRD tumors. The objective of the study is to find a score that predicts anti-PD-(L)1 response in patients with MMRD tumors.

METHODS

Sixty-one patients with various origin of MMRD tumors and treated with anti-PD-(L)1 were retrospectively included in this study. An expert radiologist annotated all tumors present at the baseline and first evaluation CT-scans for all the patients by circumscribing them on their largest axial axis (single slice), allowing us to compute an approximation of their tumor volume. In total, 2120 lesions were annotated, which led to the computation of the total tumor volume for each patient. The RECIST sum of target lesions' diameters and neutrophile-to-lymphocyte (NLR) were also reported at both examinations. These parameters were determined at baseline and first evaluation and the variation between the first evaluation and baseline was calculated, to determine a comprehensive score for overall survival (OS) and progression-free survival (PFS).

RESULTS

Total tumor volume at baseline was found to be significantly correlated to the OS (p-value: 0.005) and to the PFS (p-value:<0.001). The variation of the RECIST sum of target lesions' diameters, total tumor volume and NLR were found to be significantly associated to the OS (p-values:<0.001, 0.006,<0.001 respectively) and to the PFS (<0.001,<0.001, 0.007 respectively). The concordance score combining total tumor volume and NLR variation was better at stratifying patients compared to the tumor volume or NLR taken individually according to the OS (pairwise log-rank test p-values: 0.033,<0.001, 0.002) and PFS (pairwise log-rank test p-values: 0.041,<0.001, 0.003).

CONCLUSION

Total tumor volume appears to be a prognostic biomarker of anti-PD-(L)1 response to immunotherapy in metastatic patients with MMRD tumors. Combining tumor volume and NLR with a simple concordance score stratifies patients well according to their survival and offers a good predictive measure of response to immunotherapy.

Envafolimab - first PD-1/PD-L1 antibody to be administered by subcutaneous injection for microsatellite instability-high or deficient mismatch repair advanced solid tumors

INTRODUCTION

Programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) inhibitors mobilize and activate the anti-tumor activity of the immune system by blocking the inhibitory effects of the PD-1/PD-L1 signaling pathway in T cells. Several anti-PD-1 or -PD-L1 monoclonal antibodies have been approved for the treatment of advanced solid tumors. However, most of immune checkpoint inhibitors (ICIs) are administered via intravenous infusion, which is inconvenient and leads to unsatisfactory patient compliance in the treatment process. Therefore, subcutaneous envafolimab is to be a potential treatment modality for advanced solid tumors.

AREA COVERED

A phase I clinical trial showed that the safety and pharmacokinetic profiles of envafolimab were similar to those of other traditional antibodies. Additionally, clinical findings from a phase II trial revealed that envafolimab monotherapy exhibited satisfactory clinical therapeutic effects and no significant adverse events in patients with Microsatellite instability-high/deficient mismatch Repair (MSI-H/dMMR) solid tumors who failed at least one line of prior systemic therapy.

EXPERT OPINION

Subcutaneous envafolimab may serve as a more convenient and acceptable treatment modality than those approved PD-1/PD-L1 inhibitors for patients with an advanced solid tumor, which may revolutionize the modes of immunotherapy in the future.

Treatment patterns and real-world clinical outcomes in patients with advanced endometrial cancer that are non-microsatellite instability high (non-MSI-high) or mismatch repair proficient (pMMR) in the United States

Objective

Microsatellite instability (MSI) due to defective DNA mismatch repair has emerged as an actionable biomarker in advanced endometrial cancer (aEC). Currently, there are no treatment patterns and outcomes data in non-MSI-high (non-MSI-H) or mismatch repair proficient (pMMR) aEC patients following prior systemic therapy (FPST). Our goal was to describe real-world data in this population in the US in 2019 and prior years.

Methods

Endometrial Cancer Health Outcomes (ECHO) is a retrospective patient chart review study conducted in the US. Patients with non-MSI-H/pMMR aEC and progression between 06/01/2016-06/30/2019 FPST were eligible. Data collected included patient demographics, clinical and treatment characteristics, and clinical outcomes. Kaplan-Meier analyses were performed to estimate time to treatment discontinuation, real-world progression-free survival (rwPFS), and overall survival (OS), separately by treatment category.

Results

A total of 165 eligible patients initiated second-line therapy with chemotherapy ± bevacizumab (n = 140) or hormonal therapy (n = 25). Median age was 66.0 years at aEC diagnosis, 70.2% were Stage IIIB-IV, 40.0% had ECOG ≥ 2 at second-line therapy initiation. Median rwPFS was 5.0 months (95% CI: 4.0-6.0) for patients receiving chemotherapy ± bevacizumab and 5.5 months (95% CI: 3.0-29.0) for those receiving hormonal therapy. Median OS was 10.0 months (95% CI: 8.0-13.0) and 9.0 months (95% CI: 6.0-NA) in these groups, respectively.

Conclusions

Non-MSI-H/pMMR patients who initiated second-line therapy with chemotherapy ± bevacizumab or hormonal therapy had poor clinical outcomes with a median survival less than 1 year and rwPFS less than 6 months. This was the first study to define the clinical unmet need in patients with non-MSI-H/pMMR aEC with conventional therapy.

The Multi-Dimensional Biomarker Landscape in Cancer Immunotherapy

The field of immuno-oncology is now at the forefront of cancer care and is rapidly evolving. The immune checkpoint blockade has been demonstrated to restore antitumor responses in several cancer types. However, durable responses can be observed only in a subset of patients, highlighting the importance of investigating the tumor microenvironment (TME) and cellular heterogeneity to define the phenotypes that contribute to resistance as opposed to those that confer susceptibility to immune surveillance and immunotherapy. In this review, we summarize how some of the most widely used conventional technologies and biomarkers may be useful for the purpose of predicting immunotherapy outcomes in patients, and discuss their shortcomings. We also provide an overview of how emerging single-cell spatial omics may be applied to further advance our understanding of the interactions within the TME, and how these technologies help to deliver important new insights into biomarker discovery to improve the prediction of patient response.

Immune Checkpoint Inhibitors and Mismatch Repair Status in Advanced Endometrial Cancer: Elective Affinities

Since endometrial cancers (ECs) are frequently TMB-H and MSI-H/dMMR tumors, this element has provided the rationale for testing immune checkpoint inhibitors (ICIs), which have recently emerged as a potential game-changer. However, several questions remain to be addressed, including the identification of patients who may benefit from the addition of ICIs as well as those who do not need immunotherapy. In the current paper, we provide an overview of the clinical development of immunotherapy in advanced or recurrent EC, discussing the role of MMR and the "elective affinities" between ICIs and this predictive biomarker in this setting.

Previously treated recurrent or advanced endometrial cancer in England: A real-world observational analysis

OBJECTIVES

In patients with recurrent/advanced endometrial cancer who have progressed after first-line treatment, there are a lack of real-world data on treatment patterns, characteristics, and survival outcomes. A novel study was conducted to determine real-world treatment patterns and outcomes in England.

METHODS

This non-interventional study used routine, administrative health data from the National Cancer Registration and Analysis Service in England to identify patients diagnosed with recurrent/advanced endometrial cancer between 1 January 2013 and 31 December 2018, inclusive. A cohort of patients who progressed to second-line treatment were identified as the 'immune checkpoint inhibitor-eligible second-line' cohort. The co-primary objectives were to summarise baseline demographics, disease characteristics, treatments received, and depict overall survival and time-to-next-treatment (a proxy for progression-free survival) from the start of second-line therapy using Kaplan-Meier methodology.

RESULTS

Overall, 12,058 patients were diagnosed with recurrent/advanced endometrial cancer; 999 patients were included in the immune checkpoint inhibitor-eligible second-line cohort and 77.9% (778 of 999) had advanced disease (Stage III/IV). The most common treatments received at second-line were carboplatin plus paclitaxel (27.9%), carboplatin plus liposomal doxorubicin (14.1%), liposomal doxorubicin monotherapy (13.0%), and paclitaxel monotherapy (11.6%). From initiation of second-line therapy, median (95% confidence interval) overall survival was 10.3 months (9.2-11.1), and median time-to-next-treatment was 7.7 months (7.1-8.2).

CONCLUSIONS

Treatments received in the relapsed setting were variable and survival outcomes poor at second-line, highlighting the need for standard of care guidance and innovative therapies to improve patient outcomes in England and in countries with similar treatment patterns.

FUNDING

GSK.

Microsatellite instability and chemosensitivity in solid tumours

The use of biomarkers that influence a targeted choice in cancer treatments is the future of medical oncology. Within this scenario, in recent years, an important role has been played by knowledge of microsatellite instability (MSI), a molecular fingerprint that identifies defects in the mismatch repair system. This knowledge has changed clinical practice in the adjuvant setting of colon cancer, and its role in the neoadjuvant setting in gastric tumours is becoming increasingly interesting, as well as in endometrial cancers in both early and advanced diseases. Furthermore, it has undoubtedly conditioned the first lines of treatment in the metastatic setting in different types of cancers. The incidence of MSI is different in different cancer types, as well as in early cancers versus metastatic disease. Knowing the incidence of MSI in the various histologies can provide insight into the potential use of this biomarker considering its prognostic value, especially in the early stages, and its predictive role with respect to treatment response. In particular, MSI can guide the choice of chemotherapy treatments in the adjuvant setting of colon and perioperative setting in gastric tumours, which could lead to immunotherapy treatments in these patients in both the early stages of the disease and the metastatic setting where the response to immunotherapy drugs in diseases with MSI is now well established. In this review, we focus on colon, gastric and endometrial cancers, and we briefly discuss other cancer types where MSI could have a potential role in oncological treatment decisions.

Novel Therapies in Gynecologic Cancer

During the past decade, considerable strides have been made in the understanding and treatment of gynecologic cancers. The advent of PARP inhibitors, antiangiogenic therapies, immunotherapy combinations, and targeted agents have altered the standard of care in ovarian, endometrial, and cervical cancers. However, continued advancement in the treatment of gynecologic cancers is critical. Fortunately, exciting work defining new therapeutic targets and novel treatment strategies is on the horizon. Here, we discuss emerging treatments for gynecologic cancers, including endometrial, cervical, ovarian, and rare gynecologic cancers. We highlight research that has deepened our understanding of the unique biology and molecular underpinnings of these cancers and is being translated into powerful new treatment approaches. We particularly highlight the advent of immunotherapy in endometrial cancer; radiosensitizers in cervical, vaginal, and vulvar cancers; targeted therapies in ovarian cancer; and molecularly driven approaches to treat rare gynecologic cancers. Continued basic, translational, and clinical research holds the promise to change the landscape of gynecologic cancer and improve the lives of all women impacted by these diseases.

How Immunotherapy Modified the Therapeutic Scenario of Endometrial Cancer: A Systematic Review

Background

Endometrial cancer (EC) represents the sixth most common female tumor. In the advanced setting, the prognosis is dismal with limited treatment options. Platinum-based chemotherapy represents the actual standard of care in first-line chemotherapy, but no standard second-line chemotherapy is approved, with less than 1/4 of patients responding to second-line chemotherapy. In the last 10 years, immune checkpoint inhibitors (ICIs) have changed the treatment landscape of many solid tumors.

Methods

The review was conducted according to the PRISMA guidelines. We searched EMBASE, MEDLINE, Cochrane Database, and conference abstracts from international societies, up to November 2021. Clinical trials employing ICIs in advanced EC, written in English, were included. Reviews, letters, and commentaries were excluded. The overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety (number and grade of treatment-related adverse events [TRAEs]) were evaluated.

Results

15 studies, for a total of 1,627 patients, were included: 14 non-randomized phase I/II trials and 1 randomized phase III trial. Anti-PD1 (pembrolizumab, nivolumab, dostarlimab) and anti-PD-L1 agents (avelumab, atezolizumab, durvalumab) were administered as single agents; pembrolizumab and nivolumab were combined with the tyrosine-kinase inhibitors (TKI) lenvatinib and cabozantinib, respectively; and durvalumab was associated with anti-CTLA4 tremelimumab. 4 studies selected only MSI patients. Single agents determined an ORR from 26.7% to 58% among MSI patients, from 3% to 26.7% among MSS patients. DCR ranged from 53.5% to 88.9% in MSI, 31.4% to 35.2% in MSS patients. The combination of TKI and ICIs determined 32% to 63.6% of ORR in all-comers, 32%-36.2% in MSS patients. 54.2% to 76% of patients developed TRAEs. The combination of ICIs and TKI achieved a higher toxicity rate than single agents (≥G3 TRAEs 88.9%).

Conclusion

ICIs represent an effective option for pretreated advanced EC patients with a tolerable profile. Given the encouraging results in MSI patients, every woman diagnosed with EC should be investigated for MS status. In MSS women, the combination of ICIs and TKI is more effective than monotherapy, notwithstanding safety concerns. PD-L1 cannot predict ICI response, whereas other biomarkers such as MSI and tumor mutational burden seem more accurate. Ongoing randomized trials will further clarify the role of these therapeutic options.

Systematic Review Registration

PROSPERO, CRD42021293538.

Tumor immunotherapies by immune checkpoint inhibitors (ICIs); the pros and cons

The main breakthrough in tumor immunotherapy was the discovery of immune checkpoint (IC) proteins, which act as a potent suppressor of the immune system by a myriad of mechanisms. After that, scientists focused on the immune checkpoint molecules mainly. Thereby, much effort was spent to progress novel strategies for suppressing these inhibitory axes, resulting in the evolution of immune checkpoint inhibitors (ICIs). Then, ICIs have become a promising approach and shaped a paradigm shift in tumor immunotherapies. CTLA-4 plays an influential role in attenuation of the induction of naïve and memory T cells by engagement with its responding ligands like B7-1 (CD80) and B7-2 (CD86). Besides, PD-1 is predominantly implicated in adjusting T cell function in peripheral tissues through its interaction with programmed death-ligand 1 (PD-L1) and PD-L2. Given their suppressive effects on anti-tumor immunity, it has firmly been documented that ICIs based therapies can be practical and rational therapeutic approaches to treat cancer patients. Nonetheless, tumor inherent or acquired resistance to ICI and some treatment-related toxicities restrict their application in the clinic. The current review will deliver a comprehensive overview of the ICI application to treat human tumors alone or in combination with other modalities to support more desired outcomes and lower toxicities in cancer patients. Video Abstract.

Immune checkpoint inhibitors for recurrent endometrial cancer

INTRODUCTION

Endometrial cancer (EC) is the most common gynecologic malignancy. Outcomes for patients with advanced and/or recurrent disease have been modest with the use of chemotherapy. The approval of immune checkpoint inhibitors targeting PD-1 have recently revolutionized human cancer treatment. Recent trials with immune checkpoint inhibitors used alone or in combination with other agents, have demonstrated remarkable efficacy in the treatment of the all-comers EC patient population.

AREAS COVERED

In this article, we review major clinical trials on PD-1/PD-L1 inhibitors in advanced and recurrent EC and discuss the response rates to these agents in the context of their genomic background.

EXPERT OPINION

Immune checkpoint inhibitors have significantly changed our approach to the treatment of advanced/recurrent EC. Single agent anti-PD-1 regimens are highly effective in MMRd/MSI-H patients, but their clinical efficacy remains modest in MMR proficient/TMB low EC patients. Combination regimens that can decrease the tumor microenvironments immunosuppression and increase tumor immunogenicity represent a viable treatment option to broaden the activity of immune checkpoint inhibitors in advanced/recurrent EC patients. An increased understanding of the biomarkers of response and the molecular mechanisms of resistance to immune checkpoint inhibitors remains key for the next advancement of the field.

Endometrial Cancer: Transitioning from Histology to Genomics

Endometrial carcinoma (EC) is traditionally treated with surgery and adjuvant treatment depending on clinicopathological risk factors. The genomic analysis of EC in 2013 and subsequent studies using immunohistochemistry have led to the current EC molecular classification into: polymerase epsilon mutated (POLEmut), p53 abnormal (p53abn), mismatch repair deficient (MMRd), and no specific molecular profile (NSMP). The four groups have prognostic value and represent a promising tool for clinical decision-making regarding adjuvant treatment. Molecular classification was integrated into the recent European Society of Gynecologic Oncology (ESGO) management guidelines. POLEmut EC has favorable outcomes and retrospective studies found that omitting adjuvant treatment is safe in this group; two prospective clinical trials, PORTEC-4 and TAPER, are ongoing to assess this. p53 abn is associated with increased recurrence, decreased survival, and benefitted from chemotherapy in the PORTEC-3 subgroup molecular analysis. The clinical trials PORTEC-4a and CANSTAMP will prospectively assess this. MMRd and NSMP groups have intermediate prognosis and will likely continue to rely closely on clinicopathological features for adjuvant treatment decisions. In addition, the molecular classification has led to exploring novel treatments such as checkpoint inhibitors. Overall, the molecular perspective on EC and associated clinical trials will likely refine EC risk stratification to optimize care and avoid overtreatment.

Safety and antitumor activity of dostarlimab in patients with advanced or recurrent DNA mismatch repair deficient/microsatellite instability-high (dMMR/MSI-H) or proficient/stable (MMRp/MSS) endometrial cancer: interim results from GARNET—a phase I, single-arm study

Background

Dostarlimab is a humanized monoclonal antibody that binds with high affinity to PD-1, resulting in inhibition of binding to PD-L1 and PD-L2. We report interim data from patients with endometrial cancer (EC) participating in a phase I trial of single-agent dostarlimab.

Methods

GARNET, an ongoing, single-arm, open-label, phase I trial of intravenous dostarlimab in advanced solid tumors, is being undertaken at 123 sites. Two cohorts of patients with EC were recruited: those with dMMR/MSI-H disease (cohort A1) and those with proficient/stable (MMRp/MSS) disease (cohort A2). Patients received dostarlimab 500 mg every 3 weeks for 4 cycles, then dostarlimab 1000 mg every 6 weeks until disease progression. The primary endpoints were objective response rate (ORR) and duration of response (DOR) per RECIST V.1.1, as assessed by blinded independent central review.

Results

Screening began on April 10, 2017, and 129 and 161 patients with advanced EC were enrolled in cohorts A1 and A2, respectively. The median follow-up duration was 16.3 months (IQR 9.5–22.1) for cohort A1 and 11.5 months (IQR 11.0–25.1) for cohort A2. In cohort A1, ORR was 43.5% (95% CI 34.0% to 53.4%) with 11 complete responses and 36 partial responses. In cohort A2, ORR was 14.1% (95% CI 9.1% to 20.6%) with three complete responses and 19 partial responses. Median DOR was not reached in either cohort. In the combined cohorts, the majority of treatment-related adverse events (TRAEs) were grade 1–2 (75.5%), most commonly fatigue (17.6%), diarrhea (13.8%), and nausea (13.8%). Grade≥3 TRAEs occurred in 16.6% of patients, and 5.5% discontinued dostarlimab because of TRAEs. No deaths were attributable to dostarlimab.

Conclusion

Dostarlimab demonstrated durable antitumor activity in both dMMR/MSI-H (ORR 43.5%) and MMRp/MSS EC (ORR 14.1%) with a manageable safety profile.

Trial registration number

NCT02715284.

Can the tumor-agnostic evaluation of MSI/MMR status be the common denominator for the immunotherapy treatment of patients with several solid tumors?

Alterations in short-repetitive DNA sequences, known as microsatellite instability (MSI), can reflect deficiencies in Mismatch Repair (MMR) system which represents a major player in DNA integrity maintenance. The incidence of MSI-H/dMMR has been shown to be variable depending on the tumor type. Several studies confirmed that dMMR/MSI status, although less frequent than PD-L1 expression, may better predict response to immune-checkpoint inhibitors (ICIs) in patients with solid tumors. In October 2016, the FDA granted pembrolizumab as breakthrough therapy for the treatment of non-CRC, MSI-H/dMMR tumors, providing, for the first time, a tumor-agnostic indication. In the next future, the tissue-agnostic evaluation of MSI-H/dMMR could become the common denominator for the immunotherapy treatment of patients with different advanced solid tumors, in order to select patient subgroups which may benefit from this therapy. In this Review we provided an overview of the main clinical studies describing the association between MSI-H/dMMR tumors and immunotherapy response.

Endometrial cancer: molecular classification and future treatments

The treatment for endometrial cancer is rapidly evolving with the development of molecular analysis and novel strategies. Surgical resection, cytotoxic chemotherapy, endocrine or hormonal treatment, and radiation have been the staples of treatment for decades. However, precision based approaches for tumours are rapidly becoming a part of these strategies. Biomarker driven treatments are now a part of primary and recurrent treatment algorithms. This review aims to describe the current state of molecular analysis and treatment for endometrial cancer as well as to elucidate potential approaches for the near future.

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.

Mismatch repair and clinical response to immune checkpoint inhibitors in endometrial cancer

Endometrial cancer is common, and a subset recurs and requires additional treatment.

Some of these are recognized as being susceptible to immune therapies and are said to have mismatch repair deficiency (dMMR).

However, this clinical trial highlights which cases are more likely to respond well: those containing mutations in genes known as Lynch genes and also some with mutations in POLE/POLD1 (“ultra‐hypermutation” genes).

In contrast, the majority of dMMR endometrial cancers have silencing or DNA methylation of one of these genes, MLH1, and do not seem to be as responsive to single‐agent immune therapy.

The availability of combination therapies may be important to consider for these women.

This hypothesis‐driving study highlights the need for further evaluation of the interaction between immune checkpoint inhibitor therapy responses and the mechanism of DNA mismatch repair (MMR) deficiency. Although MMR gene germline pathogenic variant carriers and Lynch‐like tumors with double somatic MMR gene mutations are highly likely to respond to a single‐agent immune checkpoint inhibitor (ICI), those with MLH1 hypermethylation may benefit from additional agents to induce an ICI response.