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

A phase 2 trial of pembrolizumab for recurrent Lynch-like versus sporadic endometrial cancers with microsatellite instability (NCT02899793): Updated survival and response analyses

OBJECTIVE

Microsatellite instability-high (MSI-H)/mismatch repair deficiency (dMMR) is a biomarker for response to immune checkpoint inhibitors. We report updated results including objective response rate, progression free survival, and overall survival data with 5-year follow-up in recurrent platinum-resistant, MSI-H, endometrial cancer (EC) patients fully sequenced using whole exome sequencing (WES) and treated within a prospective phase II study with pembrolizumab (NCT02899793).

METHODS

Tumors from patients with measurable MSI-H/dMMR endometrial cancer confirmed by immunohistochemistry, polymerase chain reaction, and MLH-1 methylation assays were sequenced using whole exome sequencing and the FoundationOne platform for the identification of Lynch, Lynch-like, and MLH-1 methylated characteristics before receiving pembrolizumab 200 mg every 3 weeks for up to 24 months. The primary endpoint was objective response rate (ORR), and secondary endpoints were progression free survival (PFS), and overall survival (OS).

RESULTS

After almost 97 person-years of follow-up, the Lynch-like subgroup (n = 6) of MSI-H/dMMR patients continues to exhibit better ORR than the methylated (n = 18) subgroup (100 % versus 44 %, Fisher's exact P = 0.024), as well as improved PFS (unreached for Lynch-like versus 14.6 months, Log-Rank P = 0.005) and improved OS (unreached for Lynch-like versus 32.6 months, Log-Rank P = 0.058). Toxicity was manageable in both groups of MSI-H patients.

CONCLUSION

Mature follow-up results continue to suggest the prognostic significance of Lynch-like versus methylated MSI-H/dMMR features in endometrial cancer patients treated with pembrolizumab in terms of ORR, PFS, and OS. Stratification for these translational aspects may be warranted in future clinical trials with immune checkpoint inhibitors in MSI-H/dMMR endometrial cancer patients.

Molecular Classification of Endometrial Cancers Using an Integrative DNA Sequencing Panel

BACKGROUND AND OBJECTIVES

Adoption of molecular classification in endometrial cancer (EC) into clinical practice remains challenging due to complexity in coordination of multiple assays. We aimed to develop a simple molecular technique to classify ECs into four subgroups using our custom-designed targeted sequencing panel.

METHODS

Patients with newly diagnosed ECs were prospectively recruited from three cancer centres in Ontario, Canada. Using our panel, 181 ECs were sequenced. Variants were analysed for pathogenicity and clinicopathologic information was collected through medical records retrospectively.

RESULTS

Of 181, 86 (48%) were mismatch repair deficient (MMRd), of which 62 (72%) harboured MLH1 promoter methylation and 24 (28%) had pathogenic variants in MMR genes. Of single classifiers, three (1.8%) had pathogenic POLE (POLEmut), 15 (9%) had TP53 mutations (p53abn) and 61 (37%) had no specific molecular profile subtype (NSMP). Sixteen (9%) had more than one molecular classifying feature, with eight (4%) MMRd-p53abn, six (3%) POLEmut-MMRd, one (0.5%) POLEmut-MMRd-p53abn and one (0.5%) POLEmut-p53abn. When MMRd group was further subclassified according to mechanism of MMR loss, MLH1 promoter methylated group had worse outcomes than those with somatic MMR pathogenic variants.

CONCLUSIONS

Our panel can classify ECs into four subgroups through a simplified process and can be implemented reflexively in clinical practice.

First-line treatments for advanced or recurrent endometrial cancer: Systematic literature review of clinical evidence

Novel therapies are driving meaningful changes to the management of endometrial cancer (EC). Herein, a systematic literature review was conducted to evaluate the efficacy and safety of first-line treatments for advanced/recurrent EC. Searches were conducted using multiple databases through October 26, 2023. In total, 108 records of 57 unique trials (48 of first-line therapies) met the inclusion criteria. Baseline characteristics varied by study, and sample sizes ranged from 28 to 1328. Median progression-free survival was reported in 28 trials (range, 1.9-18.8 months), median overall survival in 26 trials with mature data (range, 6.9-41 months), and safety in 21 trials evaluating first-line systemic therapy ± maintenance. The potentially high risk of adverse events may outweigh the suboptimal efficacy benefits reported for conventional chemotherapy or hormonal therapies. The safety and efficacy of immunotherapies identified within are expected to contribute to a paradigm shift in the management of primary advanced/recurrent EC.

Alpelisib for PIK3CA-mutated advanced gynecological cancers: First clues of clinical activity

OBJECTIVE

Recurrent gynecological tumors (e.g., endometrial, and ovarian cancers) are incurable diseases; therefore, new treatment options are urgently needed. The PTEN-AKT-PI3K pathway is frequently altered in these tumors, representing a potential treatment target. Alpelisib is an α-specific PI3K inhibitor approved in PIK3CA-mutated advanced breast cancer. We report outcomes from a large series of patients with PIK3CA-mutated gynecological cancers prospectively treated with alpelisib within a controlled program.

METHODS

From April 2021 to December 2022, 36 patients with PIK3CA-mutated advanced gynecological cancers received alpelisib 300 mg orally once daily. Objective response (ORR) and disease control (DCR) rates provided measure of the antitumor activity of alpelisib, the primary objective of the study.

RESULTS

Included patients had endometrial (17/36 [47%]), ovarian (10/36 [28%]), or other gynecological cancers (9/36 [25%]). Most patients had received 2-3 prior systemic treatments (endometrial, 47·2%; ovarian, 60%; other, 56%), and presented with visceral metastases at baseline (82%, 70%, and 56%, respectively). Overall, 17 different PIK3CA mutations were found, including 53% in the kinase domain (most commonly H1047R) and 36% in the helical domain (most commonly E545K). Overall, the ORR was 28% and DCR was 61%, with the greatest benefit observed in patients with endometrial cancer (35% and 71%, respectively).

CONCLUSION

Alpelisib represents an active treatment option in patients with recurrent gynecological cancers harboring a PIK3CA mutation. These findings support the need of biomarker-driven randomized trials of PI3K inhibitors in gynecological cancers.

Novel Molecular Targets in Endometrial Cancer: Mechanisms and Perspectives for Therapy

Endometrial cancer (EC) has a high epidemiological impact with incidence and mortality rising worldwide. In recent years, the integration of the pathologic and molecular classification has provided relevant information to understand the heterogeneity in the biology of EC, which led to the evolution in the management of patients. Currently, therapeutic breakthroughs have been made in advanced EC to improve oncologic outcomes, with efforts to include patient reported outcomes. Precision and personalized medicine are under way in EC exploring different combination approaches to target cross-talk pathways, cancer cell microenvironment, and metabolic vulnerabilities and improve drug delivery. Yet, collaborative efforts are needed to face the challenges in practice by refining patient selection, ideal biomarker identification, and de-escalation of therapies according to emerging molecular and genomic features of EC.

Mixed Endometrial Epithelial Carcinoma: Epidemiology, Treatment and Survival Rates-A 10-Year Retrospective Cohort Study from a Single Institution

Mixed endometrial carcinoma (MEEC) refers to rare endometrial tumours that are composed of two or more distinct histotypes, at least one of which is serous or clear cell. The aim of this study was to evaluate the epidemiology, treatment outcomes and survival rates of patients with mixed endometrial carcinoma. The medical records of 34 patients diagnosed with MEEC between March 2010 and January 2020 were reviewed retrospectively. Clinicopathological variables and treatment strategies were assessed, and overall survival and disease-free survival rates were evaluated. The histology of endometrioid and serous component was found in 26 (76.5%) patients, followed by serous and clear-cell components (5/34, 14.5%) and mixed endometrioid serous and clear-cell components (3/34, 8.8%). The median age at diagnosis was 70 years (range 52-84), and the median follow-up time was 55 months. The 5-year disease-free survival and the 5-year overall survival were 50.4% and 52.4%, respectively. Advanced disease stage was identified as an independent predictor of inferior disease-free (<0.003) and overall survival (p < 0.001). Except for stage, none of the traditional prognostic factors was associated with disease recurrence or death from disease. MEECs represent rare high-risk endometrial carcinomas with significant diagnostic and treatment challenges. Undoubtedly, the implementation of a molecular analysis can offer further diagnostic and management insights.

Efficacy and Safety of PD-1/PD-L1 Inhibitor as Single-Agent Immunotherapy in Endometrial Cancer: A Systematic Review and Meta-Analysis

The programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway plays a crucial role in the immune escape mechanism and growth of cancer cells in endometrial cancer (EC). Clinical trials investigating PD-1/PD-L1 inhibitor have shown promising results in other cancers, but their efficacy in EC still remains uncertain. Therefore, this meta-analysis aims to provide an updated and robust analysis of the effectiveness and safety of PD-1/PDL1 inhibitor as single-agent immunotherapy in EC, focusing on the objective response rate (ORR), disease control rate (DCR), and adverse events (AEs). This meta-analysis utilized STATA version 17 and RevMan version 5.4 software to pool the results of relevant studies. Five studies conducted between 2017 and 2022, comprising a total of 480 EC patients enrolled for PD-1/PD-L1 inhibitor immunotherapy met the inclusion criteria. The pooled proportion of EC patients who achieved ORR through PD-1/PD-L1 inhibitor treatment was 26.0% (95% CI: 16.0-36.0%; p < 0.05). Subgroup analysis based on mismatch repair (MMR) status showed an ORR of 44.0% (95% CI: 38.0-50.0%; p = 0.32) for the deficient mismatch repair (dMMR) group and 8.0% (95% CI: 0.0-16.0%; p = 0.07) for the proficient mismatch repair (pMMR) group. Pooled proportion analysis by DCR demonstrated an odds ratio (OR) of 41.0% (95% CI: 36.0-46.0%, p = 0.83) for patients undergoing PD-1/PD-L1 inhibitor treatment. Subgroup analysis based on MMR status revealed DCR of 54.0% (95% CI: 47.0-62.0%; p = 0.83) for the dMMR group, and 31.0% (95% CI: 25.0-39.0%; p = 0.14) for the pMMR group. The efficacy of PD-1/PD-L1 inhibitors was significantly higher in the dMMR group compared to the pMMR group, in terms of both ORR (OR = 6.30; 95% CI = 3.60-11.03; p < 0.05) and DCR (OR = 2.57; 95% CI = 1.66-3.99; p < 0.05). In terms of safety issues, the pooled proportion of patients experiencing at least one adverse event was 69.0% (95% CI: 65.0-73.0%; p > 0.05), with grade three or higher AEs occurring in 16.0% of cases (95% CI: 12.0-19.0%; p > 0.05). Based on the subgroup analysis of MMR status, PD-1/PD-L1 inhibitor immunotherapy showed significantly better efficacy among dMMR patients. These findings suggest that patients with dMMR status may be more suitable for this treatment approach. However, further research on PD-1/PD-L1 inhibitor immunotherapy strategies is needed to fully explore their potential and improve treatment outcomes in EC.

Precursors of urinary bladder cancer: molecular alterations and biomarkers

Clinical surveillance and follow-up of patients diagnosed with or at risk for urinary bladder cancers represent long-term, invasive, and costly processes for which supplemental biomarker information could help provide objective, personalized risk assessment. In particular, there are several precursors and possible precursors to urinary bladder cancer for which clinical behavior is heterogenous and interobserver variability in histopathologic diagnosis make it difficult to standardize management. This review seeks to highlight these precursor lesions from a diagnostic perspective (including flat urothelial lesions, papillary urothelial lesions, squamous lesions, and glandular lesions) and qualify known multiomic biomarkers that may help explain their behavior, predict patient risk, and acknowledge the nuance inherent to the question of whether these lesions are "benign" or "preneoplastic."

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.

Angiogenesis: A Pivotal Therapeutic Target in the Drug Development of Gynecologic Cancers

Since the discovery of angiogenesis and its relevance to the tumorigenesis of gynecologic malignancies, a number of therapeutic agents have been developed over the last decade, some of which have become standard treatments in combination with other therapies. Limited clinical activity has been demonstrated with anti-angiogenic monotherapies, and ongoing trials are focused on combination strategies with cytotoxic agents, immunotherapies and other targeted treatments. This article reviews the science behind angiogenesis within the context of gynecologic cancers, the evidence supporting the targeting of these pathways and future directions in clinical trials.