Targeted treatment approaches in refractory germ cell tumors

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.

Excellent Outcomes in Children, Adolescents, and Young Adults with Ovarian Germ Cell Tumors Treated by Either Reduced- or Standard-Dose Bleomycin

To investigate the outcomes of children, adolescents, and young adults (AYAs) with malignant ovarian germ cell tumors (MOGCTs), we analyzed the data of 61 patients aged ≤39 years diagnosed with MOGCT between 2006 and 2022. Among 59 patients who received chemotherapy after initial diagnosis, 57 received BEP (standard dose of bleomycin with 30 units per week, n = 13) or bEP (reduced dose of bleomycin with 15 units/m2 on day 1, n = 44). The 5-year overall survival (OS) and event-free survival (EFS) rates were 98.3% and 84.9%, respectively. Reduced bleomycin dose did not adversely affect survival. Normalization of tumor markers within 3 months after surgery was significantly associated with better EFS (p < 0.01). Of the 59 surviving patients, 8 experienced surgery-related menopause, while 49 demonstrated menstrual recovery. After completion of chemotherapy, there was no significant difference in pulmonary function regarding bleomycin dose, and no overt nephrotoxicity. Approximately 60% and 25% of survivors experienced peripheral neuropathy at the end of chemotherapy and after 1 year, respectively (p < 0.01). Children and AYAs with MOGCT have favorable survival rates with minimal long-term toxicity, which are not influenced by a reduced bleomycin dose. Rapid normalization of tumor markers is associated with improved outcomes.

CLDN6-specific CAR-T cells plus amplifying RNA vaccine in relapsed or refractory solid tumors: the phase 1 BNT211-01 trial

The oncofetal antigen Claudin 6 (CLDN6) is highly and specifically expressed in many solid tumors, and could be a promising treatment target. We report dose escalation results from the ongoing phase 1/2 BNT211-01 trial evaluating the safety and feasibility of chimeric antigen receptor (CAR) T cells targeting the CLDN6 with or without a CAR-T cell-amplifying RNA vaccine (CARVac) at two dose levels (DLs) in relapsed/refractory CLDN6-positive solid tumors. The primary endpoints were safety and tolerability, maximum tolerated dose and recommended phase 2 dose (RP2D). Secondary endpoints included objective response rate (ORR) and disease control rate. We observed manageable toxicity, with 10 out of 22 patients (46%) experiencing cytokine release syndrome including one grade 3 event and 1 out of 22 (5%) with grade 1 immune effector cell-associated neurotoxicity syndrome. Dose-limiting toxicities occurred in two patients at the higher DL, resolving without sequelae. CAR-T cell engraftment was robust, and the addition of CARVac was well tolerated. The unconfirmed ORR in 21 evaluable patients was 33% (7 of 21), including one complete response. The disease control rate was 67% (14 of 21), with stable disease in seven patients. Patients with germ cell tumors treated at the higher DL exhibited the highest response rate (ORR 57% (4 of 7)). The maximum tolerated dose and RP2D were not established as the trial has been amended to utilize an automated manufacturing process. A repeat of the dose escalation is ongoing and will identify a RP2D for pivotal trials. ClinicalTrials.gov Identifier: NCT04503278 .

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.

Mature Cystic Teratoma: An Integrated Review

Ovarian dermoid cysts, also called mature cystic teratomas (MCTs), account for 69% of ovarian germ cell tumors in young women. The tumors are formed by tissues derived from three germ layers, and sebaceous materials are most commonly seen. The origin of MCTs is widely considered to be the germ cell origin, which completes meiosis I. The clinical symptoms vary widely, but 20% of tumors could be asymptomatic. The diagnosis of MCTs is usually made without difficulty by ultrasound and confirmed by histopathology post-operatively. The imaging findings have a high diagnostic value. The typical characteristics present in the sonographic images, including a dermoid plug or Rokitansky nodule, are considered strong evidence for a teratoma. Although the malignant transformation of MCTs is rare, it can occur in some cases, especially in women of advanced age. The treatment of MCTs depends on the risk of malignancy, the age of the patient, and the patient's fertility reserve requirement. In this article, we review the epidemiology, clinical symptoms, diagnosis criteria, cellular origin, and treatment of mature cystic teratomas.

Brain and Spinal Tumors Originating from the Germ Line Cells

Primary central nervous system germ cell tumors (CNS GCTs) are part of the GCTs in children and adults. This tumor entity presents with geographic variation, age, and sex predilection. There are two age peaks of incidence distribution at the first few months of life and in adolescence. CNS GCTs are heterogeneous in histopathological subtypes, locations, and tumor marker (AFP, β-hCG) secretions. In the WHO CNS tumor classification, GCTS are classified as germinoma and nongerminomatous GCT (NGGCT) with different subtypes (including teratoma). Excluding mature teratoma, the remaining NGGCTs are malignant (NGMGCT). In teratoma, growing teratoma syndrome and teratoma with somatic-type malignancy should be highlighted. The common intracranial locations are pineal region, neurohypophysis (NH), bifocal pineal-NH, basal ganglia, and cerebral ventricle. Above 50% of intracranial GCTs (IGCTs) present obstructive hydrocephalus. Spinal tumors are rare. Age, locations, hydrocephalus, and serum/CSF titer of β-hCG correlate with clinical manifestations. Delayed diagnosis is common in tumors arising in neurohypophysis, bifocal, and basal ganglia resulting in the increasing of physical dysfunction and hormonal deficits. Staging work-up includes CSF cytology for tumor cells and contrast-enhanced MRI of brain and spine for macroscopic metastasis before treatment commences. The therapeutic approach of CNS GCTs integrates locations, histopathology, staging, tumor marker level, and therapeutic classification. Treatment strategies include surgical biopsy/excision, chemotherapy, radiotherapy (single or combination). Secreting tumors with consistent imaging may not require histopathological diagnosis. Primary germinomas are highly radiosensitive and the therapeutic aim is to maintain high survival rate using optimal radiotherapy regimen with/without chemotherapy combination. Primary NGNGCTs are less radiosensitive. The therapeutic aim is to increase survival utilizing more intensive chemotherapy and radiotherapy. The negative prognostic factors are residue disease at the end of treatment and serum or CSF AFP level >1000 ng/mL at diagnosis. In refractory or recurrent NMGGCTs, besides high-dose chemotherapy, new therapy is necessary. Molecular profiling and analysis help for translational research. Survivors of pediatric brain tumors frequently experience cancer-related cognitive dysfunction, physical disability, pituitary hormone deficiency, and other CNS complications after cranial radiotherapy. Continuous surveillance and assessment may lead to improvements in treatment protocols, transdisciplinary interventions, after-treatment rehabilitation, and quality of life.

Surgical treatment confers prognostic significance in pediatric malignant mediastinal germ cell tumors

BACKGROUND

Primary malignant mediastinal germ cell tumors (GCTs) are rare pediatric tumors that have a poorer prognosis compared to GCTs occurring elsewhere in the body. The current study aimed to assess the prognostic factors and treatment outcomes of children with primary malignant mediastinal GCT in Taiwan.

METHODS

The authors retrospectively reviewed children 0-18 years old who were newly diagnosed with primary malignant mediastinal GCT between January 1, 2005 and December 31, 2019 and were registered in the Taiwan Pediatric Oncology Group patient registry. The impact of presenting characteristics, including sex, age, tumor stage, histology subtype, surgical treatment, and chemotherapy regimens of the patients were analyzed.

RESULTS

This study enrolled 52 children with malignant mediastinal GCT who had a median age of 16.0 (range, 6.0-17.9) years at diagnosis. The most common histological subtypes were mixed GCTs (n = 20) and yolk sac tumors (n = 15). Advanced disease stage and choriocarcinoma histology subtype were associated inferior outcomes. Children who received surgical treatment exhibited better outcomes compared to those who did not (5-year overall survival, 78% vs. 7%, p < .001). After comparing patients who received first-line cisplatin- and carboplatin-based chemotherapy, no difference in treatment outcomes was observed. Multivariate analysis showed that surgical management was the only independent predictor for superior OS.

CONCLUSIONS

Surgical treatment is recommended for mediastinal GCT. Cisplatin-based chemotherapy was not superior to carboplatin-based chemotherapy as first-line treatment and may be avoided due to toxicity concerns.

Near-Infrared Photoimmunotherapy (NIR-PIT) in Urologic Cancers

Near-infrared photoimmunotherapy (NIR-PIT) is a novel molecularly-targeted therapy that selectively kills cancer cells by systemically injecting an antibody-photoabsorber conjugate (APC) that binds to cancer cells, followed by the application of NIR light that drives photochemical transformations of the APC. APCs are synthesized by selecting a monoclonal antibody that binds to a receptor on a cancer cell and conjugating it to IRDye700DX silica-phthalocyanine dye. Approximately 24 h after APC administration, NIR light is delivered to the tumor, resulting in nearly-immediate necrotic cell death of cancer cells while causing no harm to normal tissues. In addition, NIR-PIT induces a strong immunologic effect, activating anti-cancer immunity that can be further boosted when combined with either immune checkpoint inhibitors or immune suppressive cell-targeted (e.g., regulatory T cells) NIR-PIT. Currently, a global phase III study of NIR-PIT in recurrent head and neck squamous cell carcinoma is ongoing. The first APC and NIR laser systems were approved for clinical use in September 2020 in Japan. In the near future, the clinical applications of NIR-PIT will expand to other cancers, including urologic cancers. In this review, we provide an overview of NIR-PIT and its possible applications in urologic cancers.

A pragmatic diagnostic approach to primary intracranial germ cell tumors and their treatment outcomes

Background: Primary intracranial germ cell tumors (ICGCT) are often diagnosed with tumor markers and imaging, which may avoid the need for a biopsy. An intracranial germ cell tumor with mild elevation of markers is seldom stratified as a distinct entity. Methods: Fifty-nine patients were stratified into three groups: pure germinoma (PG), secreting germinoma (SG) and non-germinomatous germ cell tumors (NGGCTs). Results: At 5 years, progression-free survival and overall survival of the three groups (PG vs SG vs NGGCT) were 91% versus 81% versus 59%, and 100% versus 82% versus 68%, respectively. There was no statistically significant difference in outcome among histologically and clinically diagnosed germinomas. Conclusion: A criterion for clinical diagnosis when a biopsy is not feasible is elucidated, and comparable outcomes were demonstrated with histologically diagnosed germinomas.

Recent advances in testicular germ cell tumours

Testicular germ cell tumours (TGCTs) are the most common solid tumours in young men and have an excellent overall cure rate and prognosis. In most patients, localised disease is cured by surgery alone, and a minority of patients receive short-course adjuvant chemotherapy to reduce the risk of further relapse. Also, in about 80% of patients, metastatic disease can be cured by systemic cisplatin-based chemotherapy. Unfortunately, for a proportion of patients, the disease exhibits platinum resistance and relapse occurs. Despite further lines of systemic treatment, cure can be difficult to achieve in these patients and ultimately about 20% of them will die from disease progression. Addressing the mechanisms underpinning platinum resistance is critical to improving the survival and chances of cure for these patients. This review describes the latest advances in TGCT research, focusing on the identification of novel biomarkers, genetic characteristics and exploring novel treatments.

Pursuing Precision: Receptor Tyrosine Kinase Inhibitors for Treatment of Pediatric Solid Tumors

Receptor tyrosine kinases are critical for the growth and proliferation of many different cancers and therefore represent a potential vulnerability that can be therapeutically exploited with small molecule inhibitors. Over forty small molecule inhibitors are currently approved for the treatment of adult solid tumors. Their use has been more limited in pediatric solid tumors, although an increasing number of single-agent and combination studies are now being performed. These agents have been quite successful in certain clinical contexts, such as the treatment of pediatric tumors driven by kinase fusions or activating mutations. By contrast, only modest activity has been observed when inhibitors are used as single agents for solid tumors that do not have genetically defined alterations in the target genes. The absence of predictive biomarkers has limited the wider applicability of these drugs and much work remains to define the appropriate patient population and clinical situation in which receptor tyrosine kinase inhibitors are most beneficial. In this manuscript, we discuss these issues by highlighting past trials and identifying future strategies that may help add precision to the use of these agents for pediatric extracranial solid tumors.

Salvage management of patients with relapsing testicular germ cell tumors

PURPOSE OF REVIEW

This review aims to summarize the latest evidence of medical and surgical treatment options for patients with relapsing testicular germ cell tumors.

RECENT FINDINGS

Depending on International Germ Cell Cancer Classification Group risk classification 10-50% of patients with metastatic TGCT develop relapse which needs further multimodality treatment. With regard to therapy, early relapses are stratified according to their prognostic risk profile which results in a 3-year overall survival between 6% in the very high to 77% in the very low risk group. Prognostic risk score dictates systemic therapy which might be second line chemotherapy (TIP, PEI) or high dose chemotherapy. Any residual masses following salvage chemotherapy need to be completely resected due the presence of viable cancer and/or teratoma in more than 50% of cases. Targeted therapy in men with druggable mutations is for individualized cases only. Patients with late relapses developing more than 2 years after first-line chemotherapy are best managed by surgery. Desperation surgery is reserved for those patients with rising markers during or immediately after chemotherapy and good risk factors such as rising alpha-fetoprotein, <3 metastatic sites and complete resectability. Multimodality treatment will result in long-term cure of 25% to 60%. Due to the complexity of treatment, chemotherapy as well as surgery should be performed in highly experienced centres only.

SUMMARY

Multimodality treatment to salvage relapsing patients with metastatic testis cancer requires extensive experience for both systemic therapy and surgery. If done properly, it will result in moderate to high cure rates. Personalized therapeutic options are currently evaluated in clinical trials.

Pembrolizumab in Patients with Advanced Metastatic Germ Cell Tumors

LESSONS LEARNED

Advanced germ cell tumors are aggressive and associated with poor prognosis. Pembrolizumab was overall well tolerated in 12 heavily pretreated patients. Three patients had radiographic stable disease that lasted for 10.9 months, 5.5 months, and 4.5 months, respectively. Published data of immunotherapeutic agents in patients with advanced germ cell tumors are confirmed. The limited antitumor activity of immunotherapy in germ cell tumors is, at least partially, attributed to tumor biology (low tumor mutational burden; low PD-1 expression) and other poor-risk features. Tumor profiling to understand the mechanisms of resistance to pembrolizumab and innovative clinical trials that may include immunotherapy are warranted.

BACKGROUND

Advanced germ cell tumors are associated with poor prognosis. We investigated the role of pembrolizumab in patients with advanced germ cell tumors.

METHODS

We analyzed a prespecified cohort of an open-label, phase II clinical trial in which patients with advanced germ cell tumors were treated with pembrolizumab (200 mg) intravenously every 21 days. The endpoints of the study were the non-progression rate (NPR) at 27 weeks, safety, and tolerability. An NPR >20% was considered successful and worthy of further pursuit.

RESULTS

From August 2016 to February 2018, 12 patients (10 men, 2 women) were treated (median age, 35 years [range, 22-63 years]; median number of prior systemic therapies, 3.5 [range, 2-7]; median number of metastatic sites, 3 [range, 2-8]). Overall, pembrolizumab was well tolerated. One patient experienced both grade 1 immune-related skin rash and grade 3 immune-related pneumonitis. No patient died from toxicity. Three patients had radiographic stable disease that lasted for 10.9 months, 5.5 months, and 4.5 months, respectively. No objective response was noted. The median progression-free survival was 2.4 months (95% confidence interval [CI], 1.5-4.5 months), and the median overall survival was 10.6 months (95% CI, 4.6-27.1 months). The 27-week NPR was 9.0% (95% CI, 0.23-41.2%).

CONCLUSION

Overall, pembrolizumab was safe and had limited antitumor activity in these patients. In the advanced, metastatic setting, tumor profiling to understand the mechanisms of resistance to immunotherapy and innovative clinical trials to identify efficacious combination regimens rather than off-label use of pembrolizumab are warranted.

Molecular Characterization of Ovarian Yolk Sac Tumor (OYST)

Simple Summary

Ovarian yolk sac tumors (OYSTs) are rare and specific therapeutic strategies are needed after the failure of platinum-based first-line and salvage regimens. This retrospective study included ten patients with OYST, including patients with relapsed disease and disease-free patients. Three patients (33.3%) harbored oncogenic mutations in KRAS, KIT and ARID1A, which may be used as a target. Our series shows that relapsed patients with molecular analysis had clinically relevant molecular alterations. Future research with dedicated trials and multicenter international collaborations are needed to demonstrate the efficacy of specific therapeutic strategies after failure of platinum-based first-line and salvage regimens.

Abstract

Most patients with malignant ovarian germ cell tumors (MOGTCs) have a very good prognosis and chemotherapy provides curative treatment; however, patients with yolk sac tumors (OYSTs) have a significantly worse prognosis. OYSTs are rare tumors and promising results are expected with the use of specific therapeutic strategies after the failure of platinum-based first-line and salvage regimens. We initiated a project in collaboration with EORTC SPECTA, to explore the molecular characteristics of OYSTs. The pilot project used retrospective samples from ten OYST relapsed and disease-free patients. Each patient had a molecular analysis performed with FoundationOne CDx describing the following variables according to the Foundation Medicine Incorporation (FMI): alteration type (SNV, deletion), actionable gene alteration, therapies approved in EU (for patient’s tumor type and other tumor types), tumor mutational burden (TMB), and microsatellite instability (MSI) status. A total of 10 patients with OYST diagnosed between 2007 and 2017 had a molecular analysis. A molecular alteration was identified in four patients (40%). A subset of three patients (33.3% of all patients) harbored targetable oncogenic mutations in KRAS, KIT, ARID1A. Two patients at relapse harbored a targetable mutation. This retrospective study identifies clinically relevant molecular alterations for all relapsed patients with molecular analysis. Dedicated studies are needed to demonstrate the efficacy of specific therapeutic strategies after the failure of platinum-based first-line and salvage regimens and to explore the potential relationship of a molecular alteration and patient outcome.

Promising novel therapies for relapsed and refractory testicular germ cell tumors

INTRODUCTION

Germ cell tumors (GCTs) are the most common solid malignancies in young men. The overall cure rate of GCT patients in metastatic stage is excellent, however; patients with relapsed or refractory disease have poor prognosis. Attempts to treat refractory disease with novel effective treatment to improve prognosis have been historically dismal and the ability to predict prognosis and treatment response in GCTs did not sufficiently improve in the last three decades.

AREAS COVERED

We performed a comprehensive literature search of PubMed/MEDLINE to identify original and review articles (years 1964-2020) reporting on current improvement salvage treatment in GCTs and novel treatment options including molecularly targeted therapy and epigenetic approach. Review articles were further searched for additional original articles.

EXPERT OPINION

Despite multimodal treatment approaches the treatment of relapsed or platinum-refractory GCTs remains a challenge. High-dose chemotherapy (HDCT) regimens with autologous stem-cell transplant (ASCT) from peripheral blood showed promising results in larger retrospective studies. Promising results from in vitro studies raised high expectations in molecular targets. So far, the lacking efficacy in small and unselected trials do not shed a light on targeted therapy. Currently, wide inclusion of patients into clinical trials is highly advised.

Immunotherapy for Metastatic Prostate Cancer: Current and Emerging Treatment Options

The advent of immunotherapy has revolutionized cancer treatment. Prostate cancer has an immunosuppressive microenvironment and a low tumor mutation burden, resulting in low neoantigen expression. The consensus was that immunotherapy would be less effective in prostate cancer. However, recent studies have reported that prostate cancer does have a high number of DNA damage and repair gene defects. Immunotherapies that have been tested in prostate cancer so far have been mainly vaccines and checkpoint inhibitors. A combination of genomically targeted therapies, with approaches to alleviate immune response and thereby make the tumor microenvironment immunologically hot, is promising.