Pembrolizumab in Patients with Advanced Metastatic Germ Cell Tumors

Clinical outcome and prognostic factors for immunotherapy-based treatments in patients with platinum-refractory germ cell tumor

BACKGROUND

Germ cell tumors (GCTs) are a heterogeneous group of cancers associated with a favorable prognosis when treated with platinum-based chemotherapy. However, patients with platinum-refractory GCTs face limited options and poorer outcomes, necessitating innovative treatment approaches. This study aims to evaluate the clinical outcomes and identify prognostic factors associated with immunotherapy-based treatments in this challenging patient population.

METHODS

This retrospective analysis included individuals with platinum-refractory GCTs treated with immunotherapy between 2017 and 2023. Clinical outcomes, safety, and biomarkers were analyzed.

RESULTS

The study included 37 male patients with a median age of 26 years (range: 18-65). The overall response rate was 24.32 %, with a median progression-free survival (PFS) and overall survival (OS) of 4.67 months and 22.67 months, respectively. Patients with both serum levels of alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) below 100 (AFP & hCG < 100) demonstrated significantly better PFS and OS. Multivariate analysis indicated that lower serum tumor marker levels (AFP & hCG < 100) and treatment initiation at earlier lines were significantly associated with improved PFS. Notably, genomic analysis revealed that one patient with an MDM4 mutation experienced hyperprogression after the initiation of immunotherapy. Immune-related adverse events occurred in two patients: one developed grade 1 hyperthyroidism, and the other experienced grade 2 immune-related pneumonitis.

CONCLUSIONS

Immunotherapy offers a promising treatment option for selected patients with platinum-refractory GCTs, demonstrating moderate response rates and potential survival benefits in a real-world scenario. Identifying specific prognostic factors may help tailor treatment strategies and enhance outcomes in this challenging patient cohort.

Treatment of recurrent ovarian germ cell tumours: Is there a role for immune checkpoint inhibitors?

Ovarian germ cell tumours predominantly affect young women and have an excellent prognosis. While most contemporary papers concentrate on reducing treatment morbidity and preserving fertility, some women still succumb to refractory or recurrent OGCTs. Despite the significant impact of immune checkpoint inhibitors (ICIs) on many tumors, no case of a chemo-resistant ovarian germ cell tumour successfully treated with immunotherapy has been reported. In testicular cancer, only a few cases of partial response or stable disease to ICIs have been described. PD-L1 expression does not predict response, but microsatellite instability status may serve as a potential biomarker. MSI testing should be performed on a recurrent tumour sample as MSI status may evolve during treatment.

Dysgerminomas: germ cell tumors exhibit high expression of PD-L1 and associated with high TILs and good prognosis

Ovarian germ cell tumors (OVGCTs) account for 28% of all diagnosed ovarian cancers, and malignant germ cell tumors specifically account for approximately 13% of diagnosed ovarian cancers in Saudi Arabia. Although most germ cell tumor patients have a high survival rate, patients who experience tumor recurrence have a poor prognosis and present with more aggressive and chemoresistant tumors. The use of immunotherapeutic agents such as PD-L1/PD-1 inhibitors for OVGCTs remains very limited because few studies have described the immunological characteristics of these tumors. This study is the first to investigate PD-L1 expression in ovarian germ cell tumors and explore the role of PD-L1 expression in tumor microenvironment cells and genetic alterations. A total of 34 ovarian germ cell tumors were collected from pathology archives. The collected tumor tissues included ten dysgerminomas, five yolk sac tumors, five immature teratomas, and one mature teratoma, and the remaining samples were mixed germ cell tumors. The tumors were analyzed using immunohistochemical analysis to determine PD-L1 expression, immune cell infiltration and cancer stem cell populations and their correlation with clinical outcome. Furthermore, the genetic alterations in different subtypes of germ cell tumors were correlated with PD-L1 expression and clinical outcome. Datasets for testicular germ cells (TGCTs) were retrieved from The Cancer Genome Atlas (TCGA) and analyzed using cBioPortal (cbioportal.org) and Gene Expression Profiling Interactive Analysis (GEPIA). Compared with yolk sac tumors, dysgerminomas highly express PD-L1 and are associated with high levels of tumor infiltrating lymphocytes (TILs) and stem cell markers. In addition, compared with PD-L1-negative yolk sac tissue, dysgerminomas/seminomas with high PD-L1 expression are associated with more genetic alterations and a better prognosis. Our findings will contribute to the knowledge about the potential benefits of ovarian cancer immunotherapy in specific subsets of germ cell tumor patients and the risk factors for resistance mediated by tumor microenvironment cells.

Unwrapping the immunological alterations in testicular germ cell tumors: From immune homeostasis to malignancy and emerging immunotherapies

BACKGROUND

Testicular germ cell tumors (TGCTs), derived from primordial germ cells, are rare malignancies with high curative potential. However, the emergence of new evidence indicating that 15% of patients experience tumor progression, leading to death, underscores the need for innovative therapeutics.

OBJECTIVES

This review aimed to explore the immune status in maintaining testicular health and the immune-related aspects of malignancy. Furthermore, it presents an overview of current data on the use of immunotherapy for TGCT patients.

RESULTS DISCUSSION

Recent advances in immunology have opened a promising avenue for studying diseases and highlighted its role in treating diseases. While the immunopathological facets of TGCTs are not fully understood, investigations suggest a complex interplay among testis-resident immune cells, testis-specific cells (i.e., Sertoli cells (SCs) and Leydig cells (LCs)), and immune-regulating mediators (e.g., sex hormones) in the normal testicle that foster the testicular immune privilege (TIP). Although TIP plays a crucial role in sperm production, it also makes testis vulnerable to tumor development. In the context of cancer-related inflammation, disruption of TIP leads to an imbalanced immune response, resulting in chronic inflammation that can contribute to testicular tissue dysfunction or loss, potentially aiding in cancer invasion and progression.

CONCLUSION

Comparing the immune profiles of normal and malignant testes is valuable and may provide insights into different aspects of testicular immunity and immune-based treatment approaches. For patients resistant to chemotherapy and with a poor prognosis, immunotherapy has shown promising results. However, its effectiveness in treating resistant TGCTs or preventing tumor recurrence is still uncertain.

Pediatric primary extragonadal choriocarcinoma - A study on male patients at a single tertiary medical institution

BACKGROUND

Primary extragonadal choriocarcinoma (PEGCC) in male is rare. It is highly malignant, typically presents with distant metastasis at the time of diagnosis, and responds poorly to treatment. Because of its associated high levels of PD-L1, the PD-1/PD-L1 pathway is a likely therapeutic target. Herein, we report our experience of treating pediatric PEGCC in six boys at a tertiary hospital.

METHODS

We analyzed the data of six boys with pathologically confirmed PEGCC between 2009 and 2021. Their clinicodemographic and histopathological characteristics as well as treatments and clinical outcomes were retrieved from their medical charts.

RESULTS

The patients' median age was 15 (range: 12-17) years. The most common primary tumor site was the mediastinum (67%, 4/6), with one case each in the retroperitoneum (16.7%) and brain (16.7%). Except for the patient with brain PEGCC, all presented with metastasis at the time of diagnosis. The following metastatic sites were observed: the lungs (100%, 5/5), brain (3/5, 60%), liver (3/5, 60%), kidneys (2/5, 40%), and spleen (1/5, 20%). Most patients had dry cough, dyspnea, and hemoptysis at initial presentation, likely due to lung metastasis. Serum human chorionic gonadotropin (HCG) levels were highly elevated in all patients. All patients received platinum-based cytotoxic chemotherapy. The patient with brain choriocarcinoma underwent surgical tumor resection; all others underwent only surgical biopsy. Strong positive PD-L1 immunohistochemical staining was noted for two patients. One patient received the PD-L1 inhibitor pembrolizumab and achieved a good response. Our cohort's 1-year survival rate was 33.3%, with a median survival of 4.34 months. Serum HCG levels remained normal in the two survivors during follow-up visits.

CONCLUSION

The poor response to current platinum-based chemotherapy remains a major challenge in the management of pediatric PEGCC. Adding pembrolizumab to a conventional chemotherapy regimen may improve the outcomes in boys with PEGCC.

The combination of immune checkpoint inhibitors and antibody-drug conjugates in the treatment of urogenital tumors: a review insights from phase 2 and 3 studies

With the high incidence of urogenital tumors worldwide, urinary system tumors are among the top 10 most common tumors in men, with prostate cancer ranking first and bladder cancer fourth. Patients with resistant urogenital tumors often have poor prognosis. In recent years, researchers have discovered numerous specific cancer antigens, which has led to the development of several new anti-cancer drugs. Using protein analysis techniques, researchers developed immune checkpoint inhibitors (ICIs) and antibody-conjugated drugs (ADCs) for the treatment of advanced urogenital tumors. However, tumor resistance often leads to the failure of monotherapy. Therefore, clinical trials of the combination of ICIs and ADCs have been carried out in numerous centers around the world. This article reviewed phase 2 and 3 clinical studies of ICIs, ADCs, and their combination in the treatment of urogenital tumors to highlight safe and effective methods for selecting individualized therapeutic strategies for patients. ICIs activate the immune system, whereas ADCs link monoclonal antibodies to toxins, which can achieve a synergistic effect when the two drugs are combined. This synergistic effect provides multiple advantages for the treatment of urogenital tumors.

The Immune Landscape and Immunotherapeutic Strategies in Platinum-Refractory Testicular Germ Cell Tumors

Testicular germ cell tumors (TGCTs) are cancers with very good prognosis, even in the metastatic setting, with high curative potential mainly attributed to the introduction of cisplatin-based chemotherapy. However, approximately 15% of the patients develop platinum-refractory disease and suffer multiple relapses. Therefore, there is an unmet need for novel therapeutic agents with improved efficacy and minimal long-term side effects. Recent advances in the development of immunotherapeutic agents, particularly immune checkpoint inhibitors (ICIs), have offered an opportunity to test their activity in various tumor types, including GCTs. This review aims to analyze the immune microenvironment of these tumors and present the most recently available data from studies that have tested immunotherapeutic agents against GCTs. The majority of the available knowledge derives from case reports or small cohort studies, particularly those involving ICIs of the PD-1/PD-L1 axis alone or in combination with anti-CTLA-4 monoclonal antibodies. Other immunotherapeutic targeted approaches, including antibody-drug conjugates, antibody prodrugs, vaccines, tyrosine kinase inhibitors, chimeric antigen receptor (CAR) T-cell therapy, have biological rationales and have shown preliminary activity or are currently being tested. Growing evidence on these and other approaches will assist in broadening the currently limited treatment armamentarium against platinum-refractory TGCTs.

Pure testicular choriocarcinoma, a rare and highly malignant subtype with challenging treatment: A case report and review of the literature

Testicular choriocarcinoma (CC) is the rarest subtype of germ cell tumours (GCTs) of the testis, with a high malignant potential and early haematogenous metastasis. Radical surgical resection should be performed primarily for histological diagnosis, while chemotherapy remains the mainstay of therapy for advanced disease. In the present study, the case of a 65-year-old male patient diagnosed with metastatic testicular CC, who did not fully respond to chemotherapy is reported. This patient underwent surgical removal of the testicular tumour, chemotherapy with etoposide and cisplatin, and radiotherapy of the intracranial lesions. Although the serum human chorionic gonadotropin (HCG) levels of the patient and most of the metastases continued decreasing during chemotherapy, complete response was not achieved after six cycles of chemotherapy. The patient refused high-dose chemotherapy and autologous stem cell transplantation due to severe side effects, and eventually developed respiratory failure on maintenance therapy with oral etoposide. A literature review was then performed, aiming to summarize the characteristics and therapeutic principles of testicular CC. In addition, the emerging therapeutic agents that could be used in maintenance therapy for GCTs, particularly for testicular CC, were also discussed. The limited clinical trials of targeted treatments showed potential benefit for long survival of patients with selected GCTs with fewer side effects. In particular, immunotherapy showed unique potential for testicular CC in preclinical studies, offering new approaches of maintenance therapy for advanced disease. Further studies should shed light on the identification of prognostic factors that predict the response to immune-based therapy in GCTs.

The efficacy of immunotherapy and chemoimmunotherapy in patients with advanced rare tumors: A Turkish oncology group (TOG) study

INTRODUCTION

The advances in immune checkpoint inhibitors (ICIs) were relatively slow in rare tumors. Therefore, we conducted a multi-center study evaluating the efficacy of ICI monotherapy and the combination of ICIs with chemotherapy (CT) in patients with advanced rare tumors.

METHODS

In this retrospective cohort study, we included 93 patients treated with ICIs for NCI-defined rare tumors from the 12 cancer centers in Turkey. The primary endpoints were the overall response (ORR) and disease control rate (DCR).

RESULTS

The cohort's median age was 56, and 53.8% of the patients were male. The most frequent diagnosis was sarcoma (29%), and 81.7% of the patients were previously treated with at least one line of systemic therapy in the advanced stage. The ORR and DCR were 36.8% and 63.2%, respectively. The germ cell tumors had the lowest ORR (0%), while the Merkel cell carcinoma had the highest ORR to ICIs (57.1%). Patients treated with ICI + ICI or ICI plus chemotherapy combinations had higher ORR (55.2% vs. 27.6%, p = 0.012) and DCR (82.8% vs. 53.4%, p = 0.008). The median OS was 13.47 (95% CI: 7.79-19.15) months, and the six and 12-month survival rates were 71% and 52%. The median duration of response was 16.59 months, and the 12-month progression-free survival rate was 66% in responders. The median time-to-treatment failure was 5.06 months (95% CI: 3.42-6.71). Three patients had high-grade irAEs with ICIs (grade 3 colitis, grade 3 gastritis, and grade 3 encephalitis in one patient each).

CONCLUSION

We observed over 30% ORR and a 13-month median OS in patients with rare cancers treated with ICI monotherapy or ICI plus CT combinations. The response rates to ICIs or ICIs plus CT significantly varied across different tumor types. Responding patients had over 2 years of survival, highlighting a need for further trials with ICIs for patients with rare tumors.

Detailed characterization of PD-1/PD-L1 and CTLA4 expression and tumor-infiltrating lymphocytes in yolk sac tumors

BACKGROUND

Immune checkpoint blockade (ICB) is considered as a promising approach for cancer treatment. However, the potency of ICB therapy in yolk sac tumors (YSTs) has not been confirmed, and the comprehensive analysis of tumor immune microenvironment and the expression of PD-1/PD-L1 and CTLA4 were also not thoroughly evaluated.

METHODS

Immunohistochemistry was performed in formalin-fixed, paraffin-embedded tumor specimens from 23 YSTs patients to detect the density and distribution of tumor-infiltrating T cells, tertiary lymphoid structures (TLSs), as well as the expression of PD-1/PD-L1 and CTLA4.

RESULTS

Overall, more than half (61 %) of all patients exhibited an immune-desert phenotype based on CD3+ T cells. PD-1 expression was identified in five tumor samples (21.7 %), and PD-L1 expression exhibited a different positive rate in tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs) (39.1 % and 17.4 %). Noteworthily, the rate of positive CTLA4 expression in both TCs and TILs was markedly higher (69.6 % and 56.5 %) than those of PD-1 and PD-L1 expression. Furthermore, TLSs were observed in 21.74 % of all tissues, and samples with TLSs exhibited significantly higher densities of TILs and higher expression of immune checkpoint molecules, particularly PD-1/PD-L1. In addition, tumors located in testes also exhibited a higher density of TILs and higher expression of immune checkpoint molecules.

CONCLUSION

Generally a high frequency of CTLA4 expression was found, PD-1/PD-L1 expression, the immune-inflamed phenotype, and TLSs were low frequency in YSTs, however, YSTs in testes showed a higher density of TILs and higher expression of immune checkpoint molecules.

A Phase II Clinical Trial of Pembrolizumab Efficacy and Safety in Advanced Renal Medullary Carcinoma

BACKGROUND

Renal medullary carcinoma (RMC) is one of most aggressive renal cell carcinomas and novel therapeutic strategies are therefore needed. Recent comprehensive molecular and immune profiling of RMC tissues revealed a highly inflamed phenotype, suggesting the potential therapeutic role for immune checkpoint therapies. We present the first prospective evaluation of an immune checkpoint inhibitor in a cohort of patients with RMC.

METHODS

A cohort of patients with locally advanced or metastatic RMC was treated with pembrolizumab 200 mg intravenously every 21 days in a phase II basket trial (ClinicalTrials.gov: NCT02721732). Responses were assessed by irRECIST. Tumor tissues were evaluated for PD-L1 expression and for tumor-infiltrating lymphocyte (TIL) levels. Somatic mutations were assessed by targeted next-generation sequencing.

RESULTS

A total of five patients were treated. All patients had advanced disease, with the majority of patients (60%) having metastatic disease at diagnosis. All patients had rapid disease progression despite pembrolizumab treatment, with a median time to progression of 8.7 weeks. One patient (patient 5) experienced sudden clinical progression immediately after treatment initiation and was thus taken off trial less than one week after receiving pembrolizumab.

CONCLUSIONS

This prospective evaluation showed no evidence of clinical activity for pembrolizumab in patients with RMC, irrespective of PD-L1 or TIL levels.

Targeting CLDN6 in germ cell tumors by an antibody-drug-conjugate and studying therapy resistance of yolk-sac tumors to identify and screen specific therapeutic options

BACKGROUND

Being the standard-of-care for four decades, cisplatin-based chemotherapy is highly efficient in treating germ cell tumors (GCT). However, often refractory patients present with a remaining (resistant) yolk-sac tumor (YST(-R)) component, resulting in poor prognosis due to lack of novel treatment options besides chemotherapy and surgery. The aim of this study was to identify novel targets for the treatment of YST by deciphering the molecular mechanisms of therapy resistance. Additionally, we screened the cytotoxic efficacy of a novel antibody-drug-conjugate targeting CLDN6 (CLDN6-ADC), as well as pharmacological inhibitors to target specifically YST.

METHODS

Protein and mRNA levels of putative targets were measured by flow cytometry, immunohistochemical stainings, mass spectrometry of formalin-fixed paraffin-embedded tissues, phospho-kinase arrays, or qRT-PCR. Cell viability, apoptosis and cell cycle assays of GCT and non-cancerous cells were performed using XTT cell viability assays or Annexin V / propidium iodide flow cytometry, respectively. Druggable genomic alterations of YST(-R) tissues were identified by the TrueSight Oncology 500 assay.

RESULTS

We demonstrated that treatment with a CLDN6-ADC enhanced apoptosis induction specifically in CLDN6+ GCT cells in comparison with non-cancerous controls. In a cell line-dependent manner, either an accumulation in the G2 / M cell cycle phase or a mitotic catastrophe was observed. Based on mutational and proteome profiling, this study identified drugs targeting the FGF, VGF, PDGF, mTOR, CHEK1, AURKA, or PARP signaling pathways as promising approaches to target YST. Further, we identified factors relevant for MAPK signaling, translational initiation and RNA binding, extracellular matrix-related processes as well as oxidative stress and immune response to be involved in therapy resistance.

CONCLUSIONS

In summary, this study offers a novel CLDN6-ADC to target GCT. Additionally, this study presents novel pharmacological inhibitors blocking FGF, VGF, PDGF, mTOR, CHEK1, AURKA, or PARP signaling for the treatment of (refractory) YST patients. Finally, this study shed light on the mechanisms of therapy resistance in YST.

Pediatric Extracranial Germ Cell Tumors: Review of Clinics and Perspectives in Application of Autologous Stem Cell Transplantation

Pediatric extracranial germ cell tumors (GCTs) are rare, accounting for approximately 3.5% of childhood cancers. Since the introduction of platinum-based chemotherapy, the survival rate of patients has improved to more than 80%. However, poor-risk subtypes of pediatric extracranial GCTs do not respond well to chemotherapy, leading to refractory or relapsed (R/R) diseases. For example, long-term survival rates of mediastinal GCTs or choriocarcinoma are less than 50%. According to reports in recent years for adult patients with R/R GCTs, the use of high-dose chemotherapy (HDCT) combined with autologous stem cell transplantation (ASCT) has clinical advantages; however, HDCT combined with ASCT has rarely been reported in pediatric GCTs. The R/R and poor-risk groups of pediatric GCTs could benefit from HDCT and ASCT.

An update on diagnostic tissue-based biomarkers in testicular tumors

Testicular cancer is rare overall but comprises the most common solid malignancy diagnosed in young men aged ∼20-40 years. Most testicular neoplasms generally fall into 2 broad categories: germ cell tumors (GCTs; ∼95%) and sex cord-stromal tumors (SCSTs ∼5%). Given the relative rarity of these tumors, diagnostic biomarkers are highly relevant for their diagnosis. Over the past several decades, diagnostic biomarkers have improved dramatically through targeted immunohistochemical and molecular characterization. Despite these recent advances, most markers are not perfectly sensitive or entirely specific. Therefore, they need to be used in combination and interpreted in context. In this review, we summarize tissue-based biomarkers relevant to the pathologist, with a focus on practical diagnostic issues that relate to testicular GCT and SCST.

Immune checkpoint inhibitors and Chimeric Antigen Receptor (CAR)-T cell therapy: Potential treatment options against Testicular Germ Cell Tumors

Germ cell tumors (GCTs) represent a heterogeneous neoplasm family affecting gonads and rarely occurring in extragonadal areas. Most of patients have a good prognosis, often even in the presence of metastatic disease; however, in almost 15% of cases, tumor relapse and platinum resistance are the main challenges. Thus, novel treatment strategies with both improved antineoplastic activity and minor treatment-related adverse events compared with platinum are really expected. In this context, the development and the high activity demonstrated by immune checkpoint inhibitors in solid tumors and, subsequently, the interesting results obtained from the use of chimeric antigen receptor (CAR-) T cell therapy in hematological tumors, have stimulated research in this direction also in GCTs. In this article, we will analyze the molecular mechanisms underlying the immune action in the development of GCTs, and we will report the data from the studies that tested the new immunotherapeutic approaches in these neoplasms.

Testicular yolk sac tumour metastasis to the L2 vertebra

The role of surgery for metastases to the vertebra from yolk sac tumours has not been established. The main treatment for disseminated disease is chemotherapy. We present a man in his 30s with a left orchiectomy for a testicular mixed germ cell tumour with a prominent yolk sac component who, 12 months later, developed an asymptomatic metastasis to the L2 vertebra unresponsive to chemotherapy and radiotherapy. The patient underwent resection of the L2 vertebral body, leaving a small residual tumour anterior to the vertebra attached to the great vessels. Pathology confirmed the diagnosis of a metastatic testicular yolk sac tumour in the vertebra. The postoperative MRI 6 months later demonstrated significant expansion of the tumour at the soft tissues anterior to the expandable titanium cage encasing the great vessels and extending to the paraspinal areas. Additional salvage surgery was not recommended because of the advanced stage of the tumour.

Pure Ovarian Dysgerminoma in a Postmenopausal Patient: A Case Report and Review of the Management

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Pure dysgerminomas in postmenopausal females are rare.

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Ovarian dysgerminoma symptoms are non-specific.

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Treatment options have traditionally included surgical resection and chemotherapy.

Background

A pure ovarian dysgerminoma in a postmenopausal female is a rare phenomenon.

Case

A 65-year-old female presented with a large pelvic mass. Following surgical debulking, the patient was diagnosed with FIGO Stage IIB ovarian dysgerminoma. She was treated with three cycles of etoposide and cisplatin and has been disease-free for 12 months.

Conclusion

Dysgerminomas in postmenopausal females are uncommon. Gynecologic oncologists should be familiar with the pathological diagnosis and treatment recommendations to achieve optimal outcomes.

The Efficacy of Immune Checkpoint Inhibitors in Rare Tumors: A Systematic Review of Published Clinical Trials

The immune checkpoint inhibitors (ICIs) entered treatment algorithms in most tumors. However, the data on the efficacy is limited in rare tumors with no phase III studies. We systemically reviewed the clinical trials evaluating the ICI efficacy in rare tumors and included a total of 47 clinical trials in this review. The ICIs demonstrated over 30% response rates in Merkel cell carcinoma and squamous cell carcinoma of the skin and became the standard of care. Additionally, the ICI efficacy was promising in thymic epithelial tumors and gestational trophoblastic neoplasia. In contrast, the ICI efficacy is limited in most sarcomas, germ cell tumors and low-grade neuroendocrine tumors. The ICI efficacy seemed to be improved with combinations targeting tumor microenvironment in sarcomas. The available evidence on ICI efficacy in rare tumors denote a need for better patient selection and novel combination strategies to improve outcomes.

Phase II trial of nivolumab monotherapy and biomarker screening in patients with chemo‐refractory germ cell tumors

Objectives

Germ cell tumors are highly susceptible to chemotherapy; however, there is a lack of established treatments for consistently relapsing germ cell tumor. Therefore, in this phase II study, we evaluated the efficacy and safety of nivolumab for relapsed germ cell tumor.

Methods

Seventeen adult patients (median age 34 years) with refractory primary germ cell tumor after second‐line or higher chemotherapy were enrolled. Nivolumab was administered over 30 min at 240 mg/body every 2 weeks until disease progression or intolerable adverse event occurrence. The primary endpoint was the overall response rate.

Result

We performed a biomarker analysis of programmed death ligand‐1 expression and genomic sequencing. Tumor histology revealed nonseminoma and seminoma in 14 and three patients, respectively. Patients were pretreated with a median of three chemotherapy lines, and three patients received high‐dose chemotherapy. The median number of nivolumab doses was 3 (range 2–46). One patient showed a partial response and three showed stable disease. Responses were durable in one patient with a partial response and one patient with stable disease (median 90 and 68 weeks, respectively). Nivolumab was well‐tolerated, with only two Grade 3 adverse events observed. Programmed death ligand‐1 expression was not associated with objective responses. Genomic sequencing revealed a high tumor mutation burden in a patient with a durable partial response. While a small subset of chemorefractory germ cell tumors may respond to nivolumab, programmed death ligand‐1 is unreliable to measure response.

Conclusions

Tumor mutation burden is a potential biomarker for future testing of germ cell tumor response.

Overcoming Chemotherapy Resistance in Germ Cell Tumors

Testicular germ cell tumors (GCTs) are highly curable malignancies. Excellent survival rates in patients with metastatic disease can be attributed to the exceptional sensitivity of GCTs to cisplatin-based chemotherapy. This hypersensitivity is probably related to alterations in the DNA repair of cisplatin-induced DNA damage, and an excessive apoptotic response. However, chemotherapy fails due to the development of cisplatin resistance in a proportion of patients. The molecular basis of this resistance appears to be multifactorial. Tracking the mechanisms of cisplatin resistance in GCTs, multiple molecules have been identified as potential therapeutic targets. A variety of therapeutic agents have been evaluated in preclinical and clinical studies. These include different chemotherapeutics, targeted therapies, such as tyrosine kinase inhibitors, mTOR inhibitors, PARP inhibitors, CDK inhibitors, and anti-CD30 therapy, as well as immune-checkpoint inhibitors, epigenetic therapy, and others. These therapeutics have been used as single agents or in combination with cisplatin. Some of them have shown promising in vitro activity in overcoming cisplatin resistance, but have not been effective in clinical trials in refractory GCT patients. This review provides a summary of current knowledge about the molecular mechanisms of cisplatin sensitivity and resistance in GCTs and outlines possible therapeutic approaches that seek to overcome this chemoresistance.

Adverse Events of Immune Checkpoint Inhibitors Therapy for Urologic Cancer Patients in Clinical Trials: A Collaborative Systematic Review and Meta-analysis

CONTEXT

Therapies based on immune checkpoint inhibitors (ICIs) are transforming the treatment landscape of urologic oncology. Nevertheless, an exhaustive overview of the toxicity spectrum of these novel therapies has yet to be provided.

OBJECTIVE

To comprehensively investigate the incidence and profile of ICI therapy-related adverse events (AEs) across urologic cancers.

EVIDENCE ACQUISITION

We searched for all clinical trials investigating the role of ICI therapy published between January 2010 and September 2021. Studies involving urologic cancers with reported overall incidence or tabulated data of treatment-related AEs (trAEs) or immune-related AEs (irAEs) were included. A systematic review and meta-analysis was performed after protocol registration in PROSPERO (CRD42021276435).

EVIDENCE SYNTHESIS

We identified 2638 records, of which 92 studies (including 22942 participants) met the inclusion criteria. The pooled overall incidence was 81.6% (95% confidence interval [CI] 78.0-84.7) for any-grade trAEs and 29.3% (95% CI 24.9-34.1) for grade ≥3 trAEs. The pooled overall incidence was 34.3% (95% CI 28.5-40.7) for any-grade irAEs and 10.2% (95%CI 8.2-12.7) for grade ≥3 irAEs. On a multivariable analysis, cancer type, therapy combination, clinical settings (perioperative vs advanced/metastatic), and drug exposure were independently associated with the occurrence of trAEs or irAEs. The overall rate of treatment-related mortality was 0.94% (140 of 14 899 participants), with pneumonitis (9.3%), pneumonia (7.9%), and respiratory failure (7.1%) being the most common causes. Immune-related mortality occurred in 0.26% (28 of 10 723) patients, with pneumonitis (35.7%), hepatic failure (10.7%), and hepatitis (7.1%) being most common.

CONCLUSIONS

Our study provides a comprehensive overview of ICI-associated AEs in urologic cancer patients. The spectrum and incidence of AEs vary across cancer types, ICI types, clinical settings, and therapy combinations. These findings provide important guidance to clinicians in counseling and management of patients with urologic cancers.

PATIENT SUMMARY

A high proportion of patients experience immune checkpoint inhibitor-associated toxicity. Physician and patient education is critical for early recognition and proper management.

Pathogenic mitochondrial dysfunction and metabolic abnormalities

Herein we trace links between biochemical pathways, pathogenesis, and metabolic diseases to set the stage for new therapeutic advances. Cellular and acellular microorganisms including bacteria and viruses are primary pathogenic drivers that cause disease. Missing from this statement are subcellular compartments, importantly mitochondria, which can be pathogenic by themselves, also serving as key metabolic disease intermediaries. The breakdown of food molecules provides chemical energy to power cellular processes, with mitochondria as powerhouses and ATP as the principal energy carrying molecule. Most animal cell ATP is produced by mitochondrial synthase; its central role in metabolism has been known for >80 years. Metabolic disorders involving many organ systems are prevalent in all age groups. Progressive pathogenic mitochondrial dysfunction is a hallmark of genetic mitochondrial diseases, the most common phenotypic expression of inherited metabolic disorders. Confluent genetic, metabolic, and mitochondrial axes surface in diabetes, heart failure, neurodegenerative disease, and even in the ongoing coronavirus pandemic.

Rapid Response to Pembrolizumab in a Chemo-Refractory Testicular Germ Cell Cancer with Microsatellite Instability-High

Testicular germ cell tumor (TGCT) is highly chemo-sensitive cancer; however, there is no established treatment for TGCT relapsed after multiple chemotherapy. Although pembrolizumab showed durable stable disease in some patients, no reliable biomarker for predicting response is available. High microsatellite instability (MSI) is rare in chemo-naïve TGCT. We report a TGCT patient with a rapid response to pembrolizumab. A 34-year-old Japanese male diagnosed with advanced TGCT underwent PCR-based testing of the primary site; it did not reveal MSI. He relapsed after four chemotherapy regimens: bleomycin, etoposide and cisplatin; paclitaxel, ifosfamide and cisplatin; vinblastine, ifosfamide and cisplatin; and irinotecan+nedaplatin with a total of 20 treatment cycles. Chemotherapy was thus discontinued. Re-examination by a CT-guided needle biopsy for progressing retroperitoneal lymph node (RPLN) metastases showed MSI-high; pembrolizumab was initiated. After only two doses, the human chorionic gonadotropin level decreased from 6500 to <1.0 IU/L. PET-CT showed shrinkage of the RPLN metastases with diminished metabolism. The patient is currently free from disease progression for 6 months from the start of pembrolizumab. This is the first report of refractory TGCT with MSI-high responding to pembrolizumab. We emphasize the utility of a metastatic-site biopsy to check the MSI status for refractory TGCT even when primary site is MSI-negative.