Application of Immune Checkpoint Inhibitors in Gynecological Cancers: What Do Gynecologists Need to Know before Using Immune Checkpoint Inhibitors?

Standard treatments for gynecological cancers include surgery, chemotherapy, and radiation therapy. However, there are limitations associated with the chemotherapeutic drugs used to treat advanced and recurrent gynecological cancers, and it is difficult to identify additional treatments. Therefore, immune checkpoint inhibitor (ICI) therapy products, including PD-1/PD-L1 inhibitors and CTLA-4 inhibitors, are in the spotlight as alternatives for the treatment of advanced gynecological cancers. Although the ICI monotherapy response rate in gynecological cancers is lower than that in melanoma or non-small cell lung cancer, the response rates are approximately 13-52%, 7-22%, and 4-17% for endometrial, ovarian, and cervical cancers, respectively. Several studies are being conducted to compare the outcomes of combining ICI therapy with chemotherapy, radiation therapy, and antiangiogenesis agents. Therefore, it is critical to determine the mechanism underlying ICI therapy-mediated anti-tumor activity and its application in gynecological cancers. Additionally, understanding the possible immune-related adverse events induced post-immunotherapy, as well as the appropriate management of diagnosis and treatment, are necessary to create a quality environment for immunotherapy in patients with gynecological cancers. Therefore, in this review, we summarize the ICI mechanisms, ICIs applied to gynecological cancers, and appropriate diagnosis and treatment of immune-related side effects to help gynecologists treat gynecological cancers using immunotherapy.

Chemotherapy-free treatment of recurrent advanced ovarian cancer: myth or reality?

Advanced ovarian cancer remains a leading cause of death from gynecologic malignancy. Surgery and, in most cases, platinum-based chemotherapy with or without maintenance with bevacizumab and/or poly-ADP ribose polymerase inhibitors (PARPi) represent the mainstay of treatment, but the disease typically recurs. The treatment of these patients represents a clinical challenge because sequential chemotherapy regimens are often used, with suboptimal outcomes and cumulative toxicity. Chemotherapy-free regimens, based on combinations of PARPi, vascular endothelial growth factor receptor inhibitors, anti-programmed cell death protein-1/programmed death-ligand 1, and anti-cytotoxic T-lymphocyte-associated protein-4 antibodies, among others, represent a valid option, with manageable toxicity profile and ease of administration. This review addresses this new strategy in the management of recurrent ovarian cancer and discusses its feasibility in the treatment landscape of the disease.

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.

WEE1 inhibition induces anti-tumor immunity by activating ERV and the dsRNA pathway

Targeted therapies represent attractive combination partners with immune checkpoint blockade (ICB) to increase the population of patients who benefit or to interdict the emergence of resistance. We demonstrate that targeting WEE1 up-regulates immune signaling through the double-stranded RNA (dsRNA) viral defense pathway with subsequent responsiveness to immune checkpoint blockade even in cGAS/STING-deficient tumors, which is a typical phenotype across multiple cancer types. WEE1 inhibition increases endogenous retroviral elements (ERVs) expression by relieving SETDB1/H3K9me3 repression through down-regulating FOXM1. ERVs trigger dsRNA stress and interferon response, increasing recruitment of anti-tumor T cells with concurrent PD-L1 elevation in multiple tumor models. Furthermore, combining WEE1 inhibition and PD-L1 blockade induced striking tumor regression in a CD8+ T cell-dependent manner. A WEE1 inhibition-induced viral defense signature provides a potentially informative biomarker for patient selection for combination therapy with WEE1 and ICB. WEE1 inhibition stimulates anti-tumor immunity and enhances sensitivity to ICB, providing a rationale for the combination of WEE1 inhibitors and ICB in clinical trials.

Assessment of immune biomarkers and establishing a triple negative phenotype in gynecologic cancers

OBJECTIVE

Immuno-oncology (IO) has rapidly evolved, with many IO therapies either approved or under investigation for multiple malignancies. Biomarkers exist that can predict response to IO therapies including PD-L1 expression, microsatellite instability (MSI), and total mutation burden (TMB). This paper serves to analyze the presence of these biomarkers across gynecologic cancers.

METHODS

A total of 16,300 gynecologic cancer specimens submitted for molecular profiling to Caris Life Sciences were reviewed. Immunohistochemistry was performed using the SP142 anti-PD-L1 clone and assessed for intensity. Next-generation sequencing, immunohistochemistry, and fragment analysis were used to determine MSI status. TMB was measured by counting all non-synonymous missense mutations found per tumor not previously described as germline alterations. Chi-Square, Fisher Exact, and the Kruskal-Wallis test were used to compare cohorts.

RESULTS

Of 16,300 specimens, 54.1% were ovarian, 37.2% uterine, 7.2% cervical, 0.3% vulvar, 1.2% vaginal, with 0.1% unspecified. MSI-H was most frequent in uterine cancer (17.7%) and only 1% of ovarian cancers. PD-L1 expression was present in 38.3% of cervical and 62.5% of vulvar cancers, but less than 8% of ovarian and uterine cancers. TMB-H was present in 21.1% cervical, 19.7% uterine, and 5% ovarian cancers. Few specimens exhibited a "triple positive" phenotype - 0.3% ovarian, 1.5% uterine, and 1.5% cervical. Associations were seen between MSI, TMB, and PD-L1 across all cancer types.

CONCLUSIONS

The frequency of individual biomarkers pertinent to IO therapy varies by cancer type. HPV-driven genital tract cancers have higher frequencies of PD-L1 expression, MSI-H, and TMBH. Endometrial cancers are characterized by MSI-H and TMB, whereas ovarian cancers have a low frequency of MSI-H and modest PD-L1 or TMBH. The incidence of 'triple positive" cases was less than 2%.

Proof of principle study of sequential combination atezolizumab and Vigil in relapsed ovarian cancer

Vigil® is a personalized vaccine that enhances tumor neoantigen expression. We investigated for the first time safety and efficacy of Vigil in combination with atezolizumab in relapsed ovarian cancer (OC) patients. This is a randomized, Phase 1 study of Vigil, an autologous tumor tissue transfected vaccine encoding for GMCSF and bi-shRNA-furin thereby creating enhanced immune activation and TGFβ expression control. Part 1 is a safety assessment of Vigil (1 × 10e7 cells/mL/21 days) plus atezolizumab (1200 mg/21 days). Part 2 is a randomized study of Vigil first (Vigil-1st) or atezolizumab first (Atezo-1st) for two cycles followed by the combination of both agents. The primary endpoint of the study was the determination of safety. Twenty-four patients were enrolled in the study; three patients to Part 1 and 21 to Part 2. Patients in Part 1 completed combination therapy without dose-limiting toxicity justifying expansion to Part 2. Twenty-one patients were randomized (1:1) to Part 2 to Vigil-1st (n = 11) or Atezo-1st (n = 10). Grade 3/4 treatment-related adverse events of Atezo-1st vs. Vigil-1st were 17.2% vs. 5.1%. Median overall survival (OS) was not reached (NR) (Vigil-1st) vs. 10.8 months (Atezo-1st) (hazard ratio [HR] 0.33). The exploratory subset analysis of BRCA^wt suggested improved OS benefit [NR in Vigil-1st vs. 5.2 months in Atezo-1st, HR 0.16, p 0.027]. The Vigil-1st combination therapy with atezolizumab was safe and results in support continued investigation in BRCA^wt patients.

4-1BB co-stimulation further enhances anti-PD-1-mediated reinvigoration of exhausted CD39+ CD8 T cells from primary and metastatic sites of epithelial ovarian cancers

BACKGROUND

Responses to immunotherapy vary between different cancer types and sites. Here, we aimed to investigate features of exhaustion and activation in tumor-infiltrating CD8 T cells at both the primary and metastatic sites in epithelial ovarian cancer.

METHODS

Tumor tissues and peripheral blood were obtained from 65 patients with ovarian cancer. From these samples, we isolated tumor-infiltrating lymphocytes (TILs) and peripheral blood mononuclear cells. These cells were used for immunophenotype using multicolor flow cytometry, gene expression profile using RNA sequencing and ex vivo functional restoration assays.

RESULTS

We found that CD39+ CD8 TILs were enriched with tumor-specific CD8 TILs, and that the activation status of these cells was determined by the differential programmed cell death protein 1 (PD-1) expression level. CD39+ CD8 TILs with high PD-1 expression (PD-1high) exhibited features of highly tumor-reactive and terminally exhausted phenotypes. Notably, PD-1high CD39+ CD8 TILs showed similar characteristics in terms of T-cell exhaustion and activation between the primary and metastatic sites. Among co-stimulatory receptors, 4-1BB was exclusively overexpressed in CD39+ CD8 TILs, especially on PD-1high cells, and 4-1BB-expressing cells displayed immunophenotypes indicating higher degrees of T-cell activation and proliferation, and less exhaustion, compared with cells not expressing 4-1BB. Importantly, 4-1BB agonistic antibodies further enhanced the anti-PD-1-mediated reinvigoration of exhausted CD8 TILs from both primary and metastatic sites.

CONCLUSION

Severely exhausted PD-1high CD39+ CD8 TILs displayed a distinctly heterogeneous exhaustion and activation status determined by differential 4-1BB expression levels, providing rationale and evidence for immunotherapies targeting co-stimulatory receptor 4-1BB in ovarian cancers.

PD-L1 Expression and CD8+ Tumor-infiltrating Lymphocytes in Different Types of Tubo-ovarian Carcinoma and Their Prognostic Value in High-grade Serous Carcinoma

The prevalence and significance of programmed death-1 ligand (PD-L1) expression in different types of tubo-ovarian carcinoma have not been well defined. We evaluated PD-L1 expression and CD8 tumor-infiltrating lymphocyte (TIL) density in whole tissue sections of 189 cases of tubo-ovarian carcinoma, including high-grade serous carcinoma (HGSC, n=100), clear cell carcinoma (CCC, n=24), endometrioid carcinoma (EmC, n=40), and mucinous carcinomas (MC, n=25). Using the tumor proportion score (TPS) with a 1% cutoff, PD-L1 expression was present in 21% of HGSC, 16.7% of CCC, 2.5% of EmC, and 4% of MC. Using the combined positive score (CPS) with a cutoff of 1, PD-L1 expression was present in 48% of HGSC, 25% of CCC, 20% of EmC, and 24% of MC. HGSC demonstrated significantly higher CD8 TIL density than CCC (P=0.013238), EmC (P=0.01341), or MC (P=0.004556). In HGSC, CD8 TIL density was directly correlated with PD-L1 positivity using either TPS (P=0.0008) or CPS (P=0.00011). Survival analysis of patients with high stage (stage III to IV) HGSC revealed PD-L1 positivity by TPS to be associated with improved progression-free survival (adjusted hazard ratio: 0.4912 vs. 2.036, P=0.0378). Although not statistically significant, a similar trend was observed in overall survival (adjusted hazard ratio: 0.3387 vs. 2.953, P=0.0548). In contrast, with CPS, no significant difference was identified between PD-L1-positive and negative groups in either progression-free survival (P=0.5086) or overall survival (P=0.7823). Neoadjuvant chemotherapy was associated with higher PD-L1 expression by TPS (P=0.00407) but not CPS. No significant difference in PD-L1 expression was detected in tumors from patients with germline BRCA1/2 mutations compared with germline mutation-negative tumors by either TPS or CPS. In conclusion, the prevalence of PD-L1 expression is variable in different types of tubo-ovarian carcinoma and is highest in HGSC. In high-stage HGSC, PD-L1 positivity in tumor cells is associated with an increased immune response and improved survival.

Ferroptosis of epithelial ovarian cancer: genetic determinants and therapeutic potential

Epithelial ovarian cancer (OVCA) is the most lethal gynecologic cancer. Current treatment for OVCA involves surgical debulking of the tumors followed by combination chemotherapies. While most patients achieve complete remission, many OVCA will recur and develop chemo-resistance. Whereas recurrent OVCA may be treated by angiogenesis inhibitors, PARP inhibitors, or immunotherapies, the clinical outcomes of recurrence OVCA are still unsatisfactory. One new promising anti-tumor strategy is ferroptosis, a novel form of regulated cell death featured by lipid peroxidation. In this review, we have summarized several recent studies on the ferroptosis of OVCA. Also, we summarize our current understanding of various genetic determinants of ferroptosis and their underlying mechanisms in OVCA. Furthermore, ferroptosis can be combined with other standard cancer therapeutics, which has shown synergistic effects. Therefore, such a combination of therapeutics could lead to new therapeutic strategies to improve the response rate and overcome resistance. By understanding the genetic determinants and underlying mechanisms, ferroptosis may have significant therapeutic potential to improve the clinical outcome of women with OVCA.

The Perfect Combination: Enhancing Patient Response to PD-1-Based Therapies in Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, with an overall 5-year survival of only 47%. As the development of novel targeted therapies is drastically necessary in order to improve patient survival, current EOC clinical trials have heavily focused on immunotherapeutic approaches, centered upon programmed cell death 1 (PD-1) inhibitors. While PD-1 monotherapies have only exhibited modest responses for patients, it has been theorized that in order to enhance EOC patient response to immunotherapy, combinatorial regimens must be investigated. In this review, unique challenges to EOC PD-1 response will be discussed, along with a comprehensive description of both preclinical and clinical studies evaluating PD-1-based combinatorial therapies. Promising aspects of PD-1-based combinatorial approaches are highlighted, while also discussing specific preclinical and clinical areas of research that need to be addressed, in order to optimize EOC patient immunotherapy response.

The Potential Role of Complement System in the Progression of Ovarian Clear Cell Carcinoma Inferred from the Gene Ontology-Based Immunofunctionome Analysis

Ovarian clear cell carcinoma (OCCC) is the second most common epithelial ovarian carcinoma (EOC). It is refractory to chemotherapy with a worse prognosis after the preliminary optimal debulking operation, such that the treatment of OCCC remains a challenge. OCCC is believed to evolve from endometriosis, a chronic immune/inflammation-related disease, so that immunotherapy may be a potential alternative treatment. Here, gene set-based analysis was used to investigate the immunofunctionomes of OCCC in early and advanced stages. Quantified biological functions defined by 5917 Gene Ontology (GO) terms downloaded from the Gene Expression Omnibus (GEO) database were used. DNA microarray gene expression profiles were used to convert 85 OCCCs and 136 normal controls into to the functionome. Relevant offspring were as extracted and the immunofunctionomes were rebuilt at different stages by machine learning. Several dysregulated pathogenic functions were found to coexist in the immunopathogenesis of early and advanced OCCC, wherein the complement-activation-alternative-pathway may be the headmost dysfunctional immunological pathway in duality for carcinogenesis at all OCCC stages. Several immunological genes involved in the complement system had dual influences on patients' survival, and immunohistochemistrical analysis implied the higher expression of C3a receptor (C3aR) and C5a receptor (C5aR) levels in OCCC than in controls.

[Current advances in immunotherapy in ovarian cancer]

Ovarian cancers express highly immunogenic tissue-specific antigens. The resulting immune infiltration is a major prognostic factor. There is therefore a strong biological rationale for the development of immunotherapy in ovarian cancer. However, based on Phase I and II clinical trials data, the efficacy of anti-PD-1 and anti-PD-L1 immune checkpoint inhibitors (ICPIs) remains limited in monotherapy in heavily pre-treated patients. Currently, the identification of predictive biomarkers of response and resistance is one of the major areas of research. Identifying effective combination of anti-PD-1 or anti-PD-L1 with other anticancer agents is another clinical need. Several combinations were evaluated. The association of ICPIs with chemotherapy (anthracyclines or carboplatin+paclitaxel) is disappointing (JAVELIN studies). The association with PARP inhibitors, anti-angiogenic agents and CTLA-4 inhibitors seems promising. Other immune therapies such as cell therapies (adoptive transfer of intra-tumor lymphocytes, CAR T cells or vaccines from dendritic cells) could be the future of immunotherapy in ovarian cancer but only early phase studies clinical data is available at this time.

Ovarian Cancer Immunotherapy: Turning up the Heat

Epithelial ovarian cancer (EOC) is the leading cause of death among gynecological malignancies. Despite surgery and chemotherapy, 5-years survival rates have improved only modestly over the past few decades remaining at 45% for advanced stages. Therefore, novel therapies are urgently needed. The presence of tumor-infiltrating lymphocytes (TILs) in OC tumor microenvironment (TME) has already proved to be correlated with overall survival (OS), while immune evasion mechanisms are associated with poor prognosis. Although these data indicate that immunotherapy has a strong rationale in OC, single agent immune-checkpoints inhibitors (ICIs) have shown only modest results in this malignancy. In this review, we will discuss immune-targeting combination therapies and adoptive cell therapy (ACT), highlighting the challenges represented by these strategies, which aim at disrupting the stroma-tumor barrier to boost immune system against ovarian cancer.

Treatment of patients with recurrent epithelial ovarian cancer for whom platinum is still an option

BACKGROUND

Ovarian cancer remains the most deadly gynecologic cancer with the majority of patients relapsing within 3 years of diagnosis. Traditional treatment paradigms linked to platinum sensitivity or resistance are currently being questioned in the setting of new diagnostic methods and treatment options.

DESIGN

Authors carried out review of the literature on key topics in treatment of recurrent epithelial ovarian cancer (EOC) when platinum is still an option; including secondary surgical cytoreduction, chemotherapy, novel treatment options, and maintenance therapy. A treatment algorithm is proposed.

RESULTS

Molecular characterization of EOC is critical to help guide treatment decisions. The role of secondary cytoreductive surgery is currently being evaluated with results from Gynecologic Oncology Group (GOG) 213 and anticipated results from DESKTOP III clinical trials. Chemotherapy backbone has remained relatively unchanged but utilizing non-platinum-based regimens is under investigation. In addition, maintenance therapy with anti-angiogenic therapy and Poly (ADP-ribose) Polymerase (PARP) inhibitors has emerged as the standard of care. Novel combinations, including immunotherapy and anti-angiogenesis agents, may further change the current landscape.

CONCLUSIONS

The treatment of recurrent EOC is rapidly changing. Clinical trial design will need to continue to evolve as many novel therapies move to the upfront setting. Ultimately, the treatment of patients with recurrent EOC must incorporate individual patient and tumor factors.

Immunotherapy in Ovarian Cancer

The phenotype and functionalities of the major immune cell subsets including myeloid cells, macrophages, dendritic cells, and T cells are altered in the ovarian cancer microenvironment. Immunosuppressive networks including inhibitory B7 family members and regulatory T cell-associated adenosine pathway have been defined in human ovarian cancer. In this review, the authors integrate emerging information on immunosuppressive mechanisms and T cell phenotype and discuss strategies of immunotherapeutic and vaccine regimens. Finally, crucial points regarding design of immuno-oncology clinical trials are reviewed.

Immunotherapies based on PD-1/PD-L1 pathway inhibitors in ovarian cancer treatment

Immunotherapies based on anti-programmed death 1/programmed death ligand 1 (PD-1/PD-L1) pathway inhibitors may turn out effective in ovarian cancer (OC) treatment. They can be used in combination with standard therapy and are especially promising in recurrent and platinum-resistant OC. There is growing evidence that the mechanism of the PD-1/PD-L1 pathway can be specific for a particular histological cancer type. Interestingly, the data have shown that the PD-1/PD-L1 pathway blockade may be effective, especially in the endometrioid type of OC. It is important to identify the cause of anti-tumor immune response suppression and exclude its other mechanisms in OC patients. It is also necessary to conduct subsequent studies to confirm in which OC cases the treatment is effective and how to select patients and combine drugs to improve patient survival.

Efficacy and Safety of Avelumab for Patients With Recurrent or Refractory Ovarian Cancer: Phase 1b Results From the JAVELIN Solid Tumor Trial

Importance

Current treatment options for progressive ovarian cancer provide limited benefit, particularly in patients whose disease has become resistant to platinum-based chemotherapy.

Objective

To assess the efficacy and safety of avelumab, an anti-programmed death-ligand 1 agent, in a cohort of patients with previously treated recurrent or refractory ovarian cancer.

Design, Setting, and Participants

In an expansion cohort of a phase 1b, open-label study (JAVELIN Solid Tumor), 125 patients with advanced ovarian cancer who had received chemotherapy including a platinum agent were enrolled between November 6, 2013, and August 27, 2015. Statistical analysis was performed from December 31, 2016, to October 9, 2018.

Intervention

Patients received avelumab, 10 mg/kg, every 2 weeks until disease progression, unacceptable toxic effects, or withdrawal from the study.

Main Outcomes and Measures

Prespecified end points in this cohort included confirmed best overall response (per Response Evaluation Criteria In Solid Tumors, version 1.1), immune-related best overall response, duration of response, progression-free survival, overall survival, results of programmed death-ligand 1 expression-based analyses, and safety.

Results

A total of 125 women (median age, 62.0 years [range, 27-84 years]) who had received a median of 3 prior lines of treatment (range, 0-10) for advanced disease were enrolled in the study. Patients received avelumab for a median of 2.8 months (range, 0.5-27.4 months), with a median follow-up of 26.6 months (range, 16-38 months). A confirmed objective response occurred in 12 patients (9.6%; 95% CI, 5.1%-16.2%), including a complete response in 1 patient (0.8%) and a partial response in 11 patients (8.8%). The 1-year progression-free survival rate was 10.2% (95% CI, 5.4%-16.7%) and median overall survival was 11.2 months (95% CI, 8.7-15.4 months). Infusion-related reactions occurred in 25 patients (20.0%). Other frequent treatment-related adverse events (any grade event occurring in ≥10% of patients) were fatigue (17 [13.6%]), diarrhea (15 [12.0%]), and nausea (14 [11.2%]). Grade 3 or higher treatment-related adverse events occurred in 9 patients (7.2%), of which only the level of lipase increased (3 [2.4%]) occurred in more than 1 patient. Twenty-one patients (16.8%) had an immune-related adverse event of any grade. No treatment-related deaths occurred.

Conclusions and Relevance

Avelumab demonstrated antitumor activity and acceptable safety in heavily pretreated patients with recurrent or refractory ovarian cancer.

Trial Registration

ClinicalTrials.gov identifier: NCT01772004.

Immunotherapy in ovarian cancer: fake news or the real deal?

Cancer immunotherapy has emerged as one of the most promising approaches in oncology, and comprises the activation of the immune system to induce tumor immune surveillance or to reverse the tumor immune escape. Different therapeutic strategies for ovarian carcinoma have evolved over the years. Already 30 years ago, the first clinical studies focused on modulating the tumor cytokine network with special attention to interferon-mediated immune responses. With the exploration of specific tumor antigens such as NY-ESO-1, which is expressed in ovarian carcinoma and other malignancies, the development of therapeutic cancer vaccines has been pursued initiating the era of personalized anti-cancer medicine. Almost at the same time, the adoptive transfer of genetically modified autologous tumor-reactive T-cells occurred, but response rates in ovarian carcinoma were disappointing. Today, probably the most promising therapeutic approach in this context is the blockade of immune checkpoints, such as programed cell death protein 1 (PD-1) and one of its ligands (PD-L1) or cytotoxic T-cell lymphocyte-associated antigen 4 (CTLA-4), which has demonstrated impressive response rates in malignant melanoma and non-small cell lung cancer. Despite increasing availability of treatment approaches that target tumor immune surveillance in ovarian carcinoma, selecting patient groups that particularly benefit from these treatment modalities is clinically challenging as predictive biomarkers are lacking. Here, we summarize different immunotherapy approaches in ovarian cancer and discuss why immunotherapy in ovarian cancer is still in its infancy.

Immunotherapy in Gynecologic Cancers: What We Know Now and Where We Are Headed

Immunotherapy, mainly in the form of immune checkpoint inhibitors (ICIs), has been transformative in both solid tumor and hematologic malignancies. Patients with previously terminal illnesses have experienced profound responses of great durability with these agents, fueling excitement among patients and providers regarding their use. Unfortunately, the gains seen in some solid tumors have not been replicated in a large percentage of patients with gynecologic cancer. This review focuses on the clinical benefits seen to date, toxicities and management when using ICIs, ways to improve prediction of who should receive immunotherapy, and a discussion of next-generation immunotherapy with cellular therapeutics and how these might relate to gynecologic cancers.

Checkpoint-inhibition in ovarian cancer: rising star or just a dream?

The introduction of checkpoint inhibitors revolutionized immuno-oncology. The efficacy of traditional immunotherapeutics, like vaccines and immunostimulants was very limited due to persistent immune-escape strategies of cancer cells. Checkpoint inhibitors target these escape mechanisms and re-direct the immune system to anti-tumor toxicity. Phenomenal results have been reported in entities like melanoma, where no other therapy was able to demonstrate survival benefit, before the introduction of immunotherapeutics. The first experience in ovarian cancer (OC) was reported for nivolumab, a fully human anti-programmed cell death protein 1 (PD1) antibody, in 2015. While the data are extraordinary for a mono-immunotherapeutic agent and very promising, they do not match up to the revolutionary results in entities like melanoma. The key to exceptional treatment response in OC, could be the identification of the most immunogenic patients. We hypothyse that BRCA mutation could be a predictor of improved response in OC. The underlying DNA-repair-deficiancy should result in increased immunogenicity because of higher mutational load and more neoantigen presentation. This hypothesis was not tested to date and should be subject to future trials. The present article gives an overview of the immunologic background of checkpoint inhibition (CI). It presents current data on nivolumab and other checkpoint-inhibitors in solid tumors and OC specifically and depicts important topics in the management of this novel substance group, such as side effect control, diagnostic PD-1/programmed cell death-ligand 1 (PD-L1) expression assessment and management of pseudoprogression.