Phase II study of homoharringtonine in patients with recurrent primary malignant central nervous system tumors

A phase 11 trial of Homoharringtonine (HHT) was performed in 15 patients with recurrent or progressive malignant glioma. The drug was administered at a initial dose of 4 mg/m²/day by continuous 5 day intravenous infusion (3 mg/m²/day x 5 days for heavily pretreated patients). Courses were repeated every 3–4 weeks upon recovery from toxicity. No objective antitumor regressions occurred. Two patients had no change in their CT brain scans for 2–3 months and one patient had stable disease for 6 months. Toxicity was tolerable and included myelosuppression and occasionally mild hypotension. Chemosensitivity testing with HHT and several other chemotherapy drugs was performed in glioma cell lines, including cell lines derived from these patients. The results suggest that HHT is an inactive drug in malignant glioma using this dose schedule.     

Neuroimaging for central nervous system tumors

Advances in neuroimaging techniques have now provided clinicians with the ability to detect CNS neoplasms at an earlier stage and to measure responses to therapy. However, errors in performing or interpreting these studies can lead to erroneous conclusions that may subsequently influence therapeutic decisions. The exact delineation of areas of tumor involvement in the brain has improved with newer imaging techniques, but this too is problematic in some patients. Evaluations of response to treatment can also be complicated by technical artifacts that can lead to inadequate differentiation of tumor from non-neoplastic tissues. Nevertheless, MRI and CT have helped clinicians to redefine the natural history of CNS tumors, reach earlier diagnoses, improve the accuracy of radiotherapy, explain adverse treatment responses, and exclude conditions that are not related directly to the tumor but that can be responsible for clinical deterioration. Newer tests that have the ability to assess tumor metabolism will further increase our understanding of these pathological processes.     

Recent advances in the treatment of central nervous system tumors

Introduction

Central nervous system (CNS) tumors cause a significant amount of morbidity and mortality. More research is needed to improve the prognosis of patients with CNS tumors, and especially for those with malignant gliomas. The advances over the last several years in the treatment of adult central nervous system tumors are reviewed here.

Materials and methods

Phase II and Phase III trials published in major peer-reviewed journals between 2005 and 2006 were examined. Adult central nervous system tumors including malignant glioma, low-grade glioma, primary central nervous system lymphoma, brain metastases, and neoplastic meningitis, were included.

Results

Phase II treatment trials for patients with gliomas dominated the literature in the time-period examined. Trials primarily addressed radiotherapy as well as chemotherapy in the treatment of gliomas. A number of trials examined targeted agents as single agents and in combination with systemic therapy in glioma patients. A few studies evaluated the role of chemotherapy and radiation in metastatic disease and primary CNS lymphoma.

Conclusions

Temozolomide is now the new standard of care in combination with radiation therapy for newly diagnosed glioblastomas. The optimal dosing and length of adjuvant temozolomide treatment remains unclear, and there remains no current role for neo-adjuvant therapy. Targeted agents that can be used in the salvage or front-line setting, alone or in combination with systemic therapy, will likely be the focus of future research. For metastatic brain tumors, more studies are needed to examine the exact role of radiosurgery, whole brain radiation, and the role of other therapies such as temozolomide or targeted agents. For primary CNS lymphomas, the role of various high-dose methotrexate regimens is being actively investigated.     

A review of gene therapy for the treatment of central nervous system tumors

The transfer of genes into tumors of the central nervous system has been touted as a novel treatment. However, several scientific and technological hurdles will have to be resolved before such strategies become useful clinical tools. This review summarizes the current knowledge in the field. Some of the gene delivery vectors employed both preclinically and clinically are those based on retroviruses, herpes simplex viruses, adenoviruses, adeno-associated viruses, and reoviruses. Cells such as fibroblasts and neural progenitor cells may also provide therapeutic value. These vectors are used to deliver into the tumor cell a variety of anticancer genes, such as those that activate chemotherapy agents, increase tumor immunogenicity, modulate tumor apoptosis and/or angiogenesis. One of the issues confronting such therapeutic strategies revolves around the blood-brain-barrier that may limit the penetration of vectors and genes form the circulation into the tumor. Results from a variety of clinical trials are becoming available. While the safety of this treatment strategy appears to have been established, therapeutic efficacy has been lacking. Additional refinements in the basic technology of vector construction and further understanding of the basic biology of gene transfer and expression will help in establishing gene therapy as clinically useful against brain tumors.     

Glioneuronal tumors of the central nervous system

Advances in the immunohistochemical detection of neuron-specific and neuronal-associated antigens have resulted in the discovery of neuronal elements in certain primary human brain tumors. The results have been not only to expand what neuropathologists commonly recognize as gangliogliomas, including the tumors now known as glioneurocytic tumor with neuropil rosettes and papillary ganglioneuroma, but also to expand the spectrum of tumor types to now include tumors such as central neurocytoma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile ganglioglioma. These discoveries have helped us to better understand the biology of these tumors and to refine our classification of them. Distinctions among these tumors include sites of predilection, such as the temporal lobe with the dysembryoplastic neuroepithelial tumors, and a spectrum of clinical aggressiveness that spans indolent “quasihamartomatous” lesions, such as the dysembryoplastic neuroepithelial tumor, to high-grade, highly aggressive tumors, such as the supratentorial primitive neuroectodermal tumor (World Health Organization Grade IV). Many of these tumors also commonly exhibit a glial component, as determined by both their histologic appearance and their immunoreactivity for glial fibrillary acidic protein. This review covers these recently described lesions, including the desmoplastic infantile ganglioglioma, the dysembryoplastic neuroepithelial tumor, the papillary glioneuronal tumor, the glioneuronal tumor with neuropil rosettes, and the mixed glioblastoma-cerebral neuroblastoma (supratentorial primitive neuroectodermal tumor), as well as the known tumors, ganglioglioma, medulloepithelioma, and medulloblastoma. For pathologists confronted by this growing array of tumors and subtypes, it is appropriate to focus on them and understand the differential diagnosis to be considered when confronted by them.     

Chemotherapy for metastatic tumors to the central nervous system

Management of patients with central nervous system metastases poses numerous challenges. This review focuses on the use of chemotherapy in these patients, addressing treatment difficulties such as drug resistance and possible solutions. The impact of the blood-brain barrier is considered less of a limitation than once thought. The advent of targeted signal transduction inhibitors is noted in this context. The current efficacy of chemotherapeutic agents and combinations is also discussed, with results from large studies highlighting a positive survival trend for chemotherapy in selected tumor histologies.     

Current immunotherapeutic strategies for central nervous system tumors

Immunotherapy has emerged as a promising tool in the management of malignant central nervous system tumors. Despite improvement in patient survival, traditional approaches, which consist mostly of surgery, radiotherapy, and chemotherapy, have been largely unsuccessful in permanently controlling these aggressive tumors. Immunotherapeutic strategies offer not only a novel approach but also an advantage in a way other modalities have been failing. Specifically, the capabilities of the immune system to recognize altered cells while leaving normal cells intact offer tremendous advantage over the conventional therapeutic approaches. This article summarizes our current understanding of immunotherapeutic treatment modalities used in clinical trials for management of malignant central nervous system tumors.     

Pembrolizumab for primary malignant melanoma of the central nervous system

Journal of Neuro-Oncology -     

Primary malignant lymphoma of the central nervous system

Between 1960 and 1983, 19 patients with primary malignant lymphoma of the central nervous system (CNS) were seen at McGill University Hospitals. The diagnosis was made at autopsy in 3 patients, and by biopsy in 16. Results of treatment were poor. All four patient who underwent surgery alone died within 2 months of diagnosis. Of 12 patients who underwent surgery and postoperative radiotherapy, 11 died between 2 and 56 months (median, 12 months) following diagnosis, and one is alive with disease at 47 months. Patterns of involvement at first recurrence and/or at autopsy were analyzed for 13 patients. Failure at the original site of involvement was unusual after treatment consisting of surgery and radiotherapy. In contrast, failure in the brain at sites other than those originally involved was common in spite of the use of whole brain irradiation. Local leptomeningeal involvement was seen in one patient whose diagnosis was made at autopsy, and cerebral spinal fluid seeding was seen in two additional patients, one within 1 month of diagnosis and one at relapse at 6 months after diagnosis. No patient developed disease outside the CNS. The limitations of current therapy for this disease are discussed, and certain suggestions made regarding the management of future patients with this diagnosis.     

Immunology of tumors of the central nervous system

Central nervous system (CNS) tumours possess special immunological features resulting from their development in an organ having a privileged immunological status. The following review gives a summary of actual data concerning their tumour-associated antigens, the immunological responses of their hosts and the mechanisms permitting them to escape from these responses. There is presently no proof of the existence of tumour-specific antigens on spontaneous glial tumours. Much progress has been made in this area with the development of monoclonal antibodies technology which mainly disclosed the profound antigenic heterogeneity of brain tumours. This heterogeneity could favour the escape of brain tumours from immunosurveillance; furthermore, it represents a major limitation to the use of monoclonal antibodies for diagnosis or therapy. Regarding the immunological responses of brain tumour patients, the main feature is a profound depression of cellular immunity creating an anergic state toward a large number of antigens. In vitro, it concerns specifically T4 helper lymphocytes: their mitogenic responses and secretion of interleukin-2 after antigenic stimuli are drastically reduced. Three phenomena have also been incriminated to explain the defect of immunosurveillance in brain tumour patients: 1) the synthesis by tumour cells of a protective mucopolysaccharidic coat, 2) the secretion by these cells of specific immunosuppressive factors related to cytokines, 3) the isolation of CNS maintained by the blood-brain barrier which regulates the circulation of immunocompetent cells between the intra- and extracerebral compartments. Currents efforts are focused on the individualization of therapy based on these biologic principles.     

Methotrexate re-challenge for recurrent primary central nervous system lymphoma

The prognosis of primary CNS lymphoma (PCNSL) recurring after methotrexate is poor (objective response rates [ORR] = 26–53 %; 1-year overall survival [OS] = 35–57 %). Salvage PCNSL chemotherapies have been based on the use of different agents to avoid cross-resistance; however, methotrexate is the most active agent in PCNSL, and methotrexate re-challenge may be an effective strategy for recurrent disease. We report our experience with methotrexate re-challenge in PCNSL. We reviewed 39 patients with histologically confirmed PCNSL who responded to methotrexate at initial diagnosis, experienced disease relapse and received methotrexate re-challenge. At the time of re-challenge, median age was 66 and median Karnofsky performance score (KPS) was 70. Median time from initial diagnosis was 26 m. Twenty-six patients were at first relapse and 13 at second or later relapse. At re-challenge, methotrexate was given in combination with other agents to 33 patients and as a single agent to six. The objective response rate was 85 %, with a complete response in 29 (75 %) patients, partial response in four (10 %) and disease progression in six (15 %). At median follow-up of 26 m, the median progression-free survival was 16 m; 1-year OS was 79 % (95 % CI 63–89) and median OS was 41 m. KPS was a prognostic factor for progression free survival (p = 0.04). In this population selected by previous methotrexate response, methotrexate re-challenge was a safe and effective strategy, indicating chemosensitivity was retained. Efficacy compared favorably to other salvage treatments suggesting methotrexate re-challenge should be considered in recurrent PCNSL patients who previously responded to methotrexate.     

Pembrolizumab: first experience with recurrent primary central nervous system (CNS) tumors

Patients with progressive primary brain tumors (PBT) are attracted to promising new treatments, even prior to convincing data. Anti-PD1 immunotherapies have been in the spotlight since publication of groundbreaking results for metastatic melanoma with pembrolizumab (PBL). Our objective was to report on the response and toxicity of PBL in patients with advanced PBT. We retrospectively reviewed the charts of 22 patients (17 adults and 5 children) with recurrent central nervous system tumors treated with PBL. We analyzed prior antineoplastic therapies, steroid usage, and outcomes. Patients received a median of two neoplastic therapies prior to PBL, and a median of three infusions of PBL in adults and four in children. Twelve patients (9 adults and 3 children) started PBL on steroids (median dose in adults 4 mg; range 2–8, and in children 1.5 mg, range 0.5–4) and five patients received steroids later during PBL treatment. Twelve patients (10 adults and 2 children) received concomitant bevacizumab with PBL. Side effects were minimal. All patients showed progressive tumor growth during therapy. Median OS from the start of PBL was 2.6 months in adults and 3.2 months in children. Two GB patients underwent tumor resection following treatment with PBL. Tumor-lymphocytic response in these cases was unremarkable, and PD-L1 immuno-staining was negative. In this series of 22 patients with recurrent primary brain tumors, PBL showed no clinical or histologic efficacy. We do not recommend further use of PBL for recurrent PBT unless convincing prospective clinical trial data are published.     

CI-980 for the treatment of recurrent or progressive malignant gliomas: national central nervous system consortium phase I-II evaluation of CI-980

OBJECTIVE: The purpose of this phase I/II trial was to determine the maximal tolerated dose of CI-980, and determine efficacy against malignant glioma. BACKGROUND: The CI-980 is a synthetic mitosis inhibitor that acts via the colchicine binding site on tubulin. Broad in vitro activity has been seen in a variety of human and murine tumor models. Phase I studies have demonstrated schedule dependent toxicity of CI-980. Dose-limiting toxicity was neurologic when CI-980 was given as a 24-hr infusion and hematologic when given over 72 hr at higher doses. METHODS: Twenty-four patients ages 29-65 entered this study. Six patients were treated on the phase I arm at three escalating dose levels ranging from 10.5 to 13.5 mg/m2, given over 72 hr. Eighteen patients were then treated at the highest tolerated dose, 13.5 mg/m2 per cycle. Treatment response was based on serial MRI imaging characteristics. RESULTS: The phase II study was stopped at the end of the first stage due to poor treatment response. There were no partial or complete responses, (0/24) 95% CI = 0-14%. Four patients (4/24) had a best treatment response of stable disease/no change. Median time to progression for all patients was 6.4 weeks (95% CI: 6-9 weeks). Dose-limiting toxicity was grade 3-4 granulocytopenia. Three episodes of neurotoxicity manifested by a moderate cerebellar dysfunction were seen. CONCLUSIONS: These results fail to demonstrate the significant activity of CI-980 against recurrent glioma.     

Clinical epidemiology for childhood primary central nervous system tumors

This work was conducted by the French Brain Tumor Data Bank (FBTDB) and aims to prospectively record all primary central nervous system tumors (PCNST), in France, for which histological diagnosis is available. Results concerning children are presented. This study analyzes the childhood cases (0–19 years) of newly diagnosed and histologically confirmed PCNST (during the years 2004–2006) which have been recorded by the FBTDB. All French neuropathology and neurosurgery departments participated in this program. Neurosurgeons and neuropathologists completed a data file containing socio-demographic, clinical, radiologic and anatomopathologic information. The Tumor Registry from Herault was authorized to compile the data files with personal identifiers. About 1,017 cases (533 boys and 484 girls) of newly diagnosed childhood PCNST have been recorded (gliomas: 52%, all other neuroepithelial tumors: 31%, craniopharyngioma: 5%, germ cell tumors, meningioma and neurinoma: approximately 3% each, all histological subtypes have been detailed). Tumor resections were performed in 83.3%, and biopsies in 16.7%. The distributions by histology, cryopreservation of the samples, age, sex, tumor site and surgery have been detailed. To our knowledge, this work is the first databank in Europe dedicated to PCNST that includes the collection of clinical, radiological and histological data (including cryopreservation of the specimen). The long term goals of the FBTDB are to create a national registry and a network to perform epidemiological studies, to implement clinical and basic research protocols, and to evaluate and harmonize the healthcare of children and adult patients affected by PCNST. Luc Bauchet, Valérie Rigau are equally contributed to this work.     

Primary central nervous system germ cell tumors

Opinion statement The prognosis of primary germ cell tumors (germinal neoplasms) of the central nervous system varies, depending on the histology and size of tumor and the extent of disease at diagnosis. Although some patients receive therapy without a tissue diagnosis, it is strongly recommended that tumor tissue samples be obtained for accurate histologic diagnosis. Modern neurosurgical navigation techniques have made tissue sampling by stereotactic biopsy a safe and rapid method of determining tumor histology. Depending on tumor location, open surgical biopsy may be required in some patients. Typically, germinomas are exquisitely radiosensitive, although pre-irradiation chemotherapy reduces the total radiation exposure and may increase the cure rate. Induction cisplatin-based chemotherapy, followed by low-dose involved field radio-therapy, has excellent overall and relapse-free survival rates and is the optimal treatment for patients with germinomas. This combined chemoradiotherapy approach is associated with minimal endocrinopathy and minimal neurocognitive dysfunction. Patients with relapses after low-dose radiation therapy can respond well to salvage therapy (chemotherapy or chemoradiotherapy) without significant sequelae. Patients with nongerminomas respond best to chemotherapy combined with radiation, although the response and cure rates are lower compared to germinomas. Patients with residual masses and normal tumor markers after primary therapy should have a second-look resection because most patients have residual teratoma or necrotic tissue and can be spared additional chemotherapy or radiation. Pure mature teratomas are cured only by surgical extirpation. Immature central nervous system teratomas appear to benefit from radical surgical resection, but higher doses of locally directed radiotherapy are required with no benefit from the usual chemotherapy.     

Molecular pathology of tumors of the central nervous system

Since the update of the 4th edition of the WHO Classification of Central Nervous System (CNS) Tumors published in 2016, particular molecular characteristics are part of the definition of a subset of these neoplasms. This combined ‘histo-molecular’ approach allows for a much more precise diagnosis of especially diffuse gliomas and embryonal CNS tumors. This review provides an update of the most important diagnostic and prognostic markers for state-of-the-art diagnosis of primary CNS tumors. Defining molecular markers for diffuse gliomas are IDH1/IDH2 mutations, 1p/19q codeletion and mutations in histone H3 genes. Medulloblastomas, the most frequent embryonal CNS tumors, are divided into four molecularly defined groups according to the WHO 2016 Classification: wingless/integrated (WNT) signaling pathway activated, sonic hedgehog (SHH) signaling pathway activated and tumor protein p53 gene (TP53)-mutant, SHH-activated and TP53-wildtype, and non-WNT/non-SHH-activated. Molecular characteristics are also important for the diagnosis of several other CNS tumors, such as RELA fusion-positive subtype of ependymoma, atypical teratoid rhabdoid tumor (AT/RT), embryonal tumor with multilayered rosettes, and solitary fibrous tumor/hemangiopericytoma. Immunohistochemistry is a helpful alternative for further molecular characterization of several of these tumors. Additionally, genome-wide methylation profiling is a very promising new tool in CNS tumor diagnostics. Much progress has thus been made by translating the most relevant molecular knowledge into a more precise clinical diagnosis of CNS tumors. Hopefully, this will enable more specific and more effective therapeutic approaches for the patients suffering from these tumors.     

VP-16, vincristine and procarbazine with radiation therapy for treatment of malignant brain tumors

Summary Twelve patients aged 34 to 65 with malignant gliomas were treated with VP-16, Procarbazine, Vincristine and concurrent radiation therapy. There were 9 patients with glioblastoma multiforme and 3 with anaplastic astrocytoma. All patients had a subtotal resection or biopsy as the initial procedure.Six patients (1 anaplastic astrocytoma) have developed progressive disease. Mean time to tumor progression was 46 weeks. This combined modality treatment program was associated with reversible hematologic toxicity which was severe in 2 patients. These data compare favorably to data obtained from similiar patients treated with radiation therapy and BCNU.