Targeting the hallmarks of ovarian cancer: The big picture

OBJECTIVE

As a result of relevant achievements in the field of translational research, several active drugs and multiple biological targets are available in ovarian cancer (OC). In this complex scenario, there is an urgent need to effectively summarize the available data in order to update conclusions, and outline perspectives.

METHODS

The results in terms of target identification and drug development have been summarized using the well-known hallmarks of cancer firstly described, and recently modified by Hanahan and Weinberg [1-2]. Published data from clinical trials have been retrieved from PubMed, Embase, CINAHL and Cochrane database. Ongoing clinical trials were searched using clinicaltrials.gov web platform, and identified using NCT number.

RESULTS

Genomic instability and angiogenesis are the most actively investigated hallmarks in high-grade serous OC, and the inhibition of tumor immune evasion appears as the emerging strategy for molecularly-driven therapy. Targeting sustained proliferative signaling through MEK and mTOR inhibitors seems the most promising approach in clear cell, and low-grade serous OC.

CONCLUSIONS

This substantial amount of data suggests that targeted therapies are already part of the clinical and therapeutic management of OC patients. The expectations of getting from translational research a better knowledge of tumor biology and therefore personalized drugs are high and worthy of maximum effort from referral centers.

Leveraging immunotherapy for the treatment of gynecologic cancers in the era of precision medicine

During the past decade significant progress in the understanding of stimulatory and inhibitory signaling pathways in immune cells has reinvigorated the field of immuno-oncology. In this review we outline the current immunotherapy based approaches for the treatment of gynecological cancers, and focus on the emerging clinical data on immune checkpoint inhibitors, adoptive cell therapies, and vaccines. It is anticipated that in the coming years biomarker-guided clinical trials, will provide for a better understanding of the mechanisms of response and resistance to immunotherapy, and guide combination treatment strategies that will extend the benefit from immunotherapy to patients with gynecologic cancers.

Learning from the "tsunami" of immune checkpoint inhibitors in 2015

2015 was marked by the tsunami of immune checkpoint inhibitors revealed by numerous FDA approvals, publications and abstracts in relation with these drugs in different cancers and settings. First, we reported all new indications of anti-CTLA4 and anti-PD1 approved by the FDA, the positive clinical trials published and the abstracts with promising results at important scientific meetings during 2015. Then, we discussed different critical issues of these new agents going from their predictive factors, combination therapies, tumor response patterns, efficacy in particular settings, side effect management to cost and economic burden.

Current and emerging treatment options in the management of advanced ovarian cancer

INTRODUCTION

Epithelial ovarian cancer is the most lethal gynecologic malignancy. Recent advances in understanding the biology and its molecular and histological diversity have led to mechanism based therapeutic strategies such as poly-ADP-ribose polymerase inhibitors (PARP) targeting homologous recombination deficient tumor cells and anti-angiogenic therapies. Clinical trial designs in ovarian cancer have to evolve to incorporate assessment of the genomic complexity and identify predictive biomarkers to improve precision of treatment and outcome.

AREAS COVERED

This review summarizes present-day strategies used in the management of ovarian cancer and novel promising therapeutic approaches in development. The article is based on English peer-reviewed articles located on MEDLINE and related abstracts presented at major international meetings.

EXPERT OPINION

Two types of molecular targeted therapies, anti-angiogenics and PARP inhibitors, have been shown to be active in randomized clinical trials and approved by regulatory agencies. Management of ovarian cancer is poised to change with the continued advancement of precision medicine that is founded upon improved understanding of disease biology; separation into histologically and molecularly defined subgroups; and the incorporation of this new knowledge into early phase drug development and novel clinical trial design.

PD-L1 expression is associated with tumor-infiltrating T cells and favorable prognosis in high-grade serous ovarian cancer

OBJECTIVE

As a negative regulator of T cells, Programmed Death Ligand 1 (PD-L1) is both an indicator and inhibitor of anti-tumor immune responses, which has led to confusion about its prognostic significance. We investigated the primary source of PD-L1 expression in epithelial ovarian cancer and its relationship to tumor-infiltrating lymphocytes (TIL) and associated gene products.

METHODS

Tissue microarrays containing high-grade serous carcinomas (HGSC) and endometrioid, clear cell and mucinous ovarian cancers from optimally debulked patients were assessed by immunohistochemistry for expression of PD-L1 and other markers (CD68, CD3, CD8, PD-1, CD103, FoxP3 and CD25). The Cancer Genome Atlas was interrogated for associations between PD-L1 expression and immune-related transcriptional and genomic features of HGSC.

RESULTS

PD-L1 was primarily expressed by tumor-associated CD68(+) macrophages rather than tumor cells. PD-L1(+) cells frequently co-localized with CD8, CD4 and PD-1(+) TIL, CD25(+)FoxP3(+) Tregs, and other TIL subsets. PD-L1(+) cells were prognostically favorable in HGSC. Moreover, the presence of both PD-L1(+) cells and CD8 TIL was associated with better prognosis than CD8 TIL alone. PD-L1 gene expression was independent of BRCA status. At the transcriptional level, PD-L1 was associated with both cytolytic (granzyme B, T-bet and IFN-γ) and suppressive (PD-1, CTLA-4, LAG3 and IDO-1) gene products.

CONCLUSIONS

PD-L1 is primarily expressed by macrophages in ovarian cancer and is strongly associated with both cytolytic and regulatory TIL subsets, resulting in a net positive association with survival. Tumors containing PD-L1(+) macrophages appear caught in an immunological stalemate that may require multi-pronged immunotherapy to alleviate.

Targeting the tumour microenvironment in ovarian cancer

The study of cancer initiation, growth, and metastasis has traditionally been focused on cancer cells, and the view that they proliferate due to uncontrolled growth signalling owing to genetic derangements. However, uncontrolled growth in tumours cannot be explained solely by aberrations in cancer cells themselves. To fully understand the biological behaviour of tumours, it is essential to understand the microenvironment in which cancer cells exist, and how they manipulate the surrounding stroma to promote the malignant phenotype. Ovarian cancer is the leading cause of death from gynaecologic cancer worldwide. The majority of patients will have objective responses to standard tumour debulking surgery and platinum-taxane doublet chemotherapy, but most will experience disease recurrence and chemotherapy resistance. As such, a great deal of effort has been put forth to develop therapies that target the tumour microenvironment in ovarian cancer. Herein, we review the key components of the tumour microenvironment as they pertain to this disease, outline targeting opportunities and supporting evidence thus far, and discuss resistance to therapy.

Prime time for immune-checkpoint targeted therapy at ASCO 2015

Cancer immunotherapy has been one of the dominant topics in oral presentations and abstracts during the 2015 annual meeting of the American Society of Clinical Oncology (ASCO). The renewed interest in immunotherapy is explained by the wide spectrum of activity, the durability of tumor responses and the rapid clinical development of immune-checkpoint targeted monoclonal antibodies. These new drugs are currently revolutionizing the field of oncology. Here we highlight what were to us the most important results announced during the annual meeting of ASCO held in Chicago, IL from May, 29th to June, 2nd 2015. In addition, we searched all the posters/published abstracts pertinent to the field of immunooncology from this year conference. Among more than 400 published abstracts on this topic, we have grouped and briefly summarized the most relevant ones.

PD-1/PD-L1 blockade in cancer treatment: perspectives and issues

Recent studies showed that tumor cells ‘edit’ host immunity in several ways to evade immune defenses in the tumor microenvironment. This phenomenon is called “cancer immune escape.” One of the most important components in this system is an immunosuppressive co-signal (immune checkpoint) mediated by the PD-1 receptor and its ligand, PD-L1. PD-1 is mainly expressed on activated T cells, whereas PD-L1 is expressed on several types of tumor cells. Preclinical studies have shown that inhibition of the interaction between PD-1 and PD-L1 enhances the T-cell response and mediates antitumor activity. Several clinical trials of PD-1/PD-L1 signal-blockade agents have exhibited dramatic antitumor efficacy in patients with certain types of solid or hematological malignancies. In this review, we highlight recent clinical trials using anti-PD-1 or anti-PD-L1 antibodies against several types of malignancies, including a trial conducted in our department, and describe the clinical perspectives and issues regarding the PD-1/PD-L1 blockade in cancer treatment.

Highlights of the San Antonio Breast Cancer Symposium 2015: part 1

38th San Antonio Breast Cancer Symposium, San Antonio, TX, USA, 8-12 December 2015 The 38th annual San Antonio Breast Cancer Symposium (SABCS) was convened in San Antonio (TX, USA) on 8-12 December 2015. More than 7000 clinicians and scientists from around the world participated in the symposium, which featured a range of presentations and keynote talks pertaining to breast cancer screening, prevention, loco-regional and systemic therapies. This two-part report highlights a selection of important studies presented at this premier breast cancer event with part 1 focusing on radiotherapy treatment, translational approaches to immunotherapy and longer term cardiotoxicity from anti-HER2 therapies. The second part of this report will discuss a range of topics including de-escalation of chemotherapy regimens in luminal A tumors, the prognostic relevance of circulating tumor cells, the optimum treatment of triple-negative breast cancer and shifting attitudes to primary surgical treatment.

Novel insights into the pathophysiology and treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma is an aggressive, treatment-resistant tumor, which continues to increase in frequency throughout the world because the causative agent, asbestos, has high economic importance, particularly in developing countries. Patients typically present with breathlessness and chest pain with pleural effusions. Median survival is around 12 months from diagnosis. Palliative chemotherapy is beneficial for mesothelioma patients with high performance status. The role of aggressive surgery remains controversial. This review will outline some of the recent advances in the development of novel therapies for malignant pleural mesothelioma, with a focus on immunological approaches.

Ovarian clear cell carcinoma, outcomes by stage: the MSK experience

OBJECTIVE

Ovarian clear cell carcinomas (OCCCs) are rare, and uncertainty exists as to the optimal treatment paradigm and validity of the FIGO staging system, especially in early-stage disease.

METHODS

We performed a retrospective cohort study of all OCCC patients diagnosed and treated at Memorial Sloan Kettering Cancer Center between January 1996 and December 2013. Progression-free survival (PFS) and overall survival (OS) were calculated by stage and race, and comparisons were made using the log-rank test. Statistical significance was set at p<0.05. Type and duration of treatment were also recorded.

RESULTS

There were 177 evaluable patients. The majority of patients were stage I at diagnosis (110/177, 62.2%). Of these, 60/110 (54.6%) were stage IA, 31/110 (28.2%) were stage IC on the basis of rupture-only, and 19/110 (17.3%) were stage IC on the basis of surface involvement and/or positive cytology of ascites or washings. Patients with stage IA and IC based on rupture-only had similar PFS/OS outcomes. Patients with stage IC based on surface involvement and/or positive cytology had a statistically significant decrement in PFS/OS. Stage was an important indicator of PFS/OS, while race was not.

CONCLUSIONS

OCCC often presents in early stage. Women with stage IA OCCC have excellent prognosis, and future studies should explore whether they benefit from adjuvant chemotherapy. Women with IC OCCC need further staging clarification, as surgical rupture alone affords better prognosis than surface involvement and/or positive cytology. Women with advanced OCCC have poor survival and are often chemotherapy resistant/refractory. New treatment paradigms are needed.