Nitroso-urea-cisplatin-based chemotherapy associated with valproate: increase of haematologic toxicity

Valproate and lithium: Old drugs for new pharmacological approaches in brain tumors?

Beyond its use as an antiepileptic drug, over time valproate has been increasingly used for several other therapeutic applications. Among these, the antineoplastic effects of valproate have been assessed in several in vitro and in vivo preclinical studies, suggesting that this agent significantly inhibits cancer cell proliferation by modulating multiple signaling pathways. During the last years various clinical trials have tried to find out if valproate co-administration could enhance the antineoplastic activity of chemotherapy in glioblastoma patients and in patients suffering from brain metastases, demonstrating that the inclusion of valproate in the therapeutic schedule causes an improved median overall survival in some studies, but not in others. Thus, the effects of the use of concomitant valproate in brain cancer patients are still controversial. Similarly, lithium has been tested as an anticancer drug in several preclinical studies mainly using the unregistered formulation of lithium chloride salts. Although, there are no data showing that the anticancer effects of lithium chloride are superimposable to the registered lithium carbonate, this formulation has shown preclinical activity in glioblastoma and hepatocellular cancers. However, few but interesting clinical trials have been performed with lithium carbonate on a very small number of cancer patients. Based on published data, valproate could represent a potential complementary therapeutic approach to enhance the anticancer activity of brain cancer standard chemotherapy. Same advantageous characteristics are less convincing for lithium carbonate. Therefore, the planning of specific phase III studies is necessary to validate the repositioning of these drugs in present and future oncological research.

Antitumor Potential of Antiepileptic Drugs in Human Glioblastoma: Pharmacological Targets and Clinical Benefits

Glioblastoma (GBM) is characterized by fast-growing cells, genetic and phenotypic heterogeneity, and radio-chemo-therapy resistance, contributing to its dismal prognosis. Various medical comorbidities are associated with the natural history of GBM. The most disabling and greatly affecting patients' quality of life are neurodegeneration, cognitive impairment, and GBM-related epilepsy (GRE). Hallmarks of GBM include molecular intrinsic mediators and pathways, but emerging evidence supports the key role of non-malignant cells within the tumor microenvironment in GBM aggressive behavior. In this context, hyper-excitability of neurons, mediated by glutamatergic and GABAergic imbalance, contributing to GBM growth strengthens the cancer-nervous system crosstalk. Pathogenic mechanisms, clinical features, and pharmacological management of GRE with antiepileptic drugs (AEDs) and their interactions are poorly explored, yet it is a potentially promising field of research in cancer neuroscience. The present review summarizes emerging cooperative mechanisms in oncogenesis and epileptogenesis, focusing on the neuron-to-glioma interface. The main effects and efficacy of selected AEDs used in the management of GRE are discussed in this paper, as well as their potential beneficial activity as antitumor treatment. Overall, although still many unclear processes overlapping in GBM growth and seizure onset need to be elucidated, this review focuses on the intriguing targeting of GBM-neuron mutual interactions to improve the outcome of the so challenging to treat GBM.

Epilepsy treatment in neuro-oncology: A rationale for drug choice in common clinical scenarios

Epilepsy represents a challenge in the management of patients with brain tumors. Epileptic seizures are one of the most frequent comorbidities in neuro-oncology and may be the debut symptom of a brain tumor or a complication during its evolution. Epileptogenic mechanisms of brain tumors are not yet fully elucidated, although new factors related to the underlying pathophysiological process with possible treatment implications have been described. In recent years, the development of new anti-seizure medications (ASM), with better pharmacokinetic profiles and fewer side effects, has become a paradigm shift in many clinical scenarios in neuro-oncology, being able, for instance, to adapt epilepsy treatment to specific features of each patient. This is crucial in several situations, such as patients with cognitive/psychiatric comorbidity, pregnancy, or advanced age, among others. In this narrative review, we provide a rationale for decision-making in ASM choice for neuro-oncologic patients, highlighting the strengths and weaknesses of each drug. In addition, according to current literature evidence, we try to answer some of the most frequent questions that arise in daily clinical practice in patients with epilepsy related to brain tumors, such as, which patients are the best candidates for ASM and when to start it, what is the best treatment option for each patient, and what are the major pitfalls to be aware of during follow-up.

Relevant pharmacological interactions between alkylating agents and antiepileptic drugs: Preclinical and clinical data

Seizures are relatively common in cancer patients, and co-administration of chemotherapeutic and antiepileptic drugs (AEDs) is highly probable and necessary in many cases. Nonetheless, clinically relevant interactions between chemotherapeutic drugs and AEDs are rarely summarized and pharmacologically described. These interactions can cause insufficient tumor and seizure control or lead to unforeseen toxicity. This review focused on pharmacokinetic and pharmacodynamic interactions between alkylating agents and AEDs, helping readers to make a rational choice of treatment optimization, and thus improving patients' quality of life. As an example, phenobarbital, phenytoin, and carbamazepine, by increasing the hepatic metabolism of cyclophosphamide, ifosfamide and busulfan, yield smaller peak concentrations and a reduced area under the plasma concentration-time curve (AUC) of the prodrugs; alongside, the maximum concentration and AUC of their active products were increased with the possible onset of severe adverse drug reactions. On the other side, valproic acid, acting as histone deacetylase inhibitor, showed synergistic effects with temozolomide when tested in glioblastoma. The present review is aimed at providing evidence that may offer useful suggestions for rational pharmacological strategies in patients with seizures symptoms undertaking alkylating agents. Firstly, clinicians should avoid the use of enzyme-inducing AEDs in combination with alkylating agents and prefer the use of AEDs, such as levetiracetam, that have a low or no impact on hepatic metabolism. Secondly, a careful therapeutic drug monitoring of both alkylating agents and AEDs (and their active metabolites) is necessary to maintain therapeutic ranges and to avoid serious adverse reactions.

Effectiveness and tolerability of lacosamide as add-on therapy in patients with brain tumor-related epilepsy: Results from a prospective, noninterventional study in European clinical practice (VIBES)

Objective

To evaluate the effectiveness and tolerability of lacosamide added to one or two antiepileptic drugs (AEDs) in the treatment of patients with brain tumor–related epilepsy (BTRE), and to evaluate patients’ global impression of change and quality of life (QoL).

Methods

This was a prospective, multicenter, single‐arm, noninterventional study with a 6‐month observation period (EP0045; NCT02276053). Eligible patients (≥16 years old) had active BTRE secondary to low‐grade glioma (World Health Organization grade 1 and 2) and were receiving treatment with one or two AEDs at baseline. Lacosamide was initiated by the treating physician in the course of routine clinical practice. Primary outcomes were 50% responders (≥50% reduction in focal seizure frequency from baseline) and Patient's Global Impression of Change (PGIC) at month 6. Secondary outcomes included seizure‐free status and Clinical Global Impression of Change (CGIC) at month 6, change in QoL (5‐Level EuroQol‐5 Dimension Quality of Life Assessment) and symptom outcomes (MD Anderson Symptom Inventory–Brain Tumor) from baseline to month 6, and Kaplan‐Meier estimated 6‐month retention on lacosamide. Safety variables included adverse drug reactions (ADRs).

Results

Patients were recruited from 24 sites in Europe. Ninety‐three patients received lacosamide (mean [standard deviation] age = 44.5 [14.7] years; 50 [53.8%] male; median baseline focal seizure frequency = five seizures/28 days [range = 1‐280]), of whom 79 (84.9%) completed the study. At 6 months, 66 of 86 (76.7%) patients were 50% responders and 30 of 86 (34.9%) were seizure‐free. Improvements on PGIC were reported by 49 of 76 (64.5%) patients. Based on CGIC, 52 of 81 (64.2%) patients improved. QoL and symptoms outcome measures remained stable. Kaplan‐Meier estimated 6‐month retention rate was 86.0% (N = 93). Fifteen (16.1%) patients reported ADRs; four (4.3%) had ADRs leading to discontinuation (N = 93).

Significance

Results of this prospective, noninterventional study suggest that add‐on lacosamide is effective and generally well tolerated in patients with BTRE.

Acute Neurological Complications of Brain Tumors and Immune Therapies, a Guideline for the Neuro-hospitalist

PURPOSE OF REVIEW

Patients with brain tumors presenting to the emergency room with acute neurologic complications may warrant urgent investigations and emergent management. As the neuro-hospitalist will likely encounter this complex patient population, an understanding of the acute neurologic issues will have value.

RECENT FINDINGS

We discuss updated information and management regarding various acute neurologic complications among neuro-oncology patients and neurologic complications of immunotherapy. Understanding of the acute neurologic complications associated with central nervous system tumors and with common contemporary cancer treatments will facilitate the neuro-hospitalist management of these patient populations. While there are aspects analogous to the diagnosis and management in the non-oncologic population, a number of unique features discussed in this review should be considered.

Epileptogenesis and oncogenesis: An antineoplastic role for antiepileptic drugs in brain tumours?

The first description of epileptic seizures due to brain tumours occurred in 19th century. Nevertheless, after over one hundred years, scientific literature is still lacking on how epilepsy and its treatment can affect tumour burden, progression and clinical outcomes. In patients with brain tumours, epilepsy dramatically impacts their quality of life (QoL). Even antiepileptic therapy seems to affect tumor lesion development. Numerous studies suggest that certain actors involved in epileptogenesis (inflammatory changes, glutamate and its ionotropic and metabotropic receptors, GABA-A and its GABA-AR receptor, as well as certain ligand- and voltage-gated ion channel) may also contribute to tumorigenesis. Although some antiepileptic drugs (AEDs) are known operating on such mechanisms underlying epilepsy and tumor development, few preclinical and clinical studies have tried to investigate them as targets of pharmacological tools acting to control both phenomena. The primary aim of this review is to summarize known determinants and pathophysiological mechanisms of seizures, as well as of cell growth and spread, in patients with brain tumors. Therefore, a special focus will be provided on the anticancer effects of commonly prescribed AEDs (including levetiracetam, valproic acid, oxcarbazepine and others), with an overview of both preclinical and clinical data. Potential clinical applications of this finding are discussed.

Management of epilepsy in brain tumors

Epilepsy in brain tumors (BTE) may require medical attention for a variety of unique concerns: epileptic seizures, possible serious adverse effects of antineoplastic and antiepileptic drugs (AEDs), physical disability, and/or neurocognitive disturbances correlated to tumor site. Guidelines for the management of tumor-related epilepsies are lacking. Treatment is not standardized, and overall management might differ according to different specialists. The aim of this document was to provide directives on the procedures to be adopted for a correct diagnostic-therapeutic path of the patient with BTE, evaluating indications, risks, and benefits. A board comprising neurologists, epileptologists, neurophysiologists, neuroradiologists, neurosurgeons, neuro-oncologists, neuropsychologists, and patients' representatives was formed. The board converted diagnostic and therapeutic problems into seventeen questions. A literature search was performed in September-October 2017, and a total of 7827 unique records were retrieved, of which 148 constituted the core literature. There is no evidence that histological type or localization of the brain tumor affects the response to an AED. The board recommended to avoid enzyme-inducing antiepileptic drugs because of their interference with antitumoral drugs and consider as first-choice newer generation drugs (among them, levetiracetam, lamotrigine, and topiramate). Valproic acid should also be considered. Both short-term and long-term prophylaxes are not recommended in primary and metastatic brain tumors. Management of seizures in patients with BTE should be multidisciplinary. The panel evidenced conflicting or lacking data regarding the role of EEG, the choice of therapeutic strategy, and timing to withdraw AEDs and recommended high-quality long-term studies to standardize BTE care.

Tumor-related epilepsy: epidemiology, pathogenesis and management

INTRODUCTION

Seizure is a common comorbidity in patients with brain tumor. It may be the presenting symptom or develop after the tumor diagnosis. The underlying pathophysiology of brain tumor-related epilepsy remains poorly understood.

METHODS

A comprehensive literature review of Pubmed English articles from 1980-2017 was performed to summarize current knowledge and treatment options of brain tumor-related epilepsy.

RESULTS

Multiple factors have been found to contribute to tumor-related epilepsy, including tumor type, speed of tumor growth, location, and tumor burden. The underlying pathogenesis of epilepsy is not clear but perturbations in the peri-tumoral regions, both structural and cellular communications, have been implicated.

CONCLUSIONS

Surgical and medical treatments of tumor-related epilepsy remain challenging as additional factors such as the extent of surgical resection, interactions with tumor-related oncological treatments and anti-epileptic medication related side effects need to be considered.

Efficacy and safety of Levetiracetam vs. other antiepileptic drugs in Hispanic patients with glioblastoma

Epilepsy is a common symptom in patients with glioblastoma (GB). 213 patients with GB from RedLANO follow-up registry were included. All patients underwent surgery, if feasible, followed by chemoradiation based on temozolomide (Stupp platform). Information was recorded regarding demographics, seizure timing, anti-epileptic drugs (AEDs), dosage, time to next seizure, total seizures in 6 months, and main side effects of AEDs. The relationship between epilepsy treatment and overall survival (OS) was evaluated. Mean age was 53 years old and 56.8% were male. Seventy-eight patients (37%) were treated with levetiracetam (LEV), 27% were given another AED and 36% did not require any AED. Choice of AED was not associated with age (p = 0.67), performance status (p = 0.24) or anatomic tumor site (p = 0.34). Seizures and AED requirement were greater in those having primary GB (p = 0.04). After starting an AED, the mean time until next crisis was 9.9 days (SD ± 6.3), which was shorter in those receiving LEV (p = 0.03); mean number of seizures during the first 3 and 6 months were 2.9 and 4, respectively. Most patients treated with LEV (n = 46) required less than two medication adjustments compared to those treated with other AEDs (p = 0.02). Likewise, less patients exposed to LEV required a coadjuvant drug (p = 0.04). Additionally, patients receiving LEV had significantly less adverse effects compared to patients treated with another AED. OS was significantly higher in the group treated with LEV compared to other AEDs (25.5 vs. 17.9 months; p = 0.047). Patients treated with LEV had better seizure control and longer OS compared to other AEDs.

Patterns of care of brain tumor-related epilepsy. A cohort study done in Italian Epilepsy Center

Epilepsy is the most common comorbidity in patients with brain tumors.

STUDY AIMS

To define characteristics of brain tumor-related epilepsy (BTRE) patients and identify patterns of care. Nationwide, multicenter retrospective cohort study. Medical records of BTRE patients seen from 1/1/2010 to 12/31/2011, followed for at least one month were examined. Information included age, sex, tumor type/treatments, epilepsy characteristics, antiepileptic drugs (AEDs). Time to modify first AED due to inefficacy and/or toxicity was assessed with the Kaplan-Meier method and Cox proportional hazard models were used to identify predictors of treatment outcome. Enrolled were 808 patients (447 men, 361 women) from 26 epilepsy centers. Follow-up ranged 1 to 423 months (median 18 months). 732 patients underwent surgery, 483 chemotherapy (CT), 508 radiotherapy. All patients were treated with AEDs. Levetiracetam was the most common drug. 377 patients (46.7%) were still on first drug at end of follow-up, 338 (41.8%) needed treatment modifications (uncontrolled seizures, 229; side effects, 101; poor compliance, 22). Treatment discontinuation for lack of efficacy was associated with younger age, chemotherapy, and center with <20 cases. Treatment discontinuation for side effects was associated with female sex, enzyme-inducing drugs and center with > 20 cases. About one-half of patients with BTRE were on first AED at end of follow-up. Levetiracetam was the most common drug. A non enzyme-inducing AED was followed by a lower risk of drug discontinuation for SE.

Anticonvulsant therapy in brain-tumor related epilepsy

Background. The lifetime risk of patients with brain tumors to have focal epileptic seizures is 10-100%; the risk depends on different histology. Specific guidelines for drug treatment of brain tumor-related seizures have not yet been established.

Aim. This review addresses the special aspects of antiepileptic drug (AED) therapy in brain tumor-related epilepsy.

Methods. We analyzed the literature up to December 2015.

Results. Based on current evidence the management of tumor-related seizures does not differ substantially from that applied to epilepsies from other etiologies. Therefore, the choice of an AED is based, above all, on tolerability and pharmacokinetic interactions with chemotherapeutic drugs. Levetiracetam is recommended by many authors as first-line therapy in brain tumor-related epilepsy. Due to the possibility of interactions, the combination of enzyme-inducing AEDs and chemotherapeutic drugs, is usually not recommended as a first choice. Currently there is no evidence that prophylactic prescription of long-term AEDs in brain tumor-patients who did not present with seizures is justified. Because of the high risk of recurrence, however, AED treatment should be strongly considered after a single brain tumor-related seizure. The decision to withdraw AEDs must carefully consider the risk of seizure recurrence.

Conclusion. At present levetiracetam is the preferred drug in brain tumor-related epilepsy, especially when drug interactions need to be avoided. In the future we hope to acquire more targeted drugs against this disorder by uncovering its pathogenesis.

Epilepsy and brain tumors

Seizures are common in patients with brain tumors, and epilepsy can significantly impact patient quality of life. Therefore, a thorough understanding of rates and predictors of seizures, and the likelihood of seizure freedom after resection, is critical in the treatment of brain tumors. Among all tumor types, seizures are most common with glioneuronal tumors (70-80%), particularly in patients with frontotemporal or insular lesions. Seizures are also common in individuals with glioma, with the highest rates of epilepsy (60-75%) observed in patients with low-grade gliomas located in superficial cortical or insular regions. Approximately 20-50% of patients with meningioma and 20-35% of those with brain metastases also suffer from seizures. After tumor resection, approximately 60-90% are rendered seizure-free, with most favorable seizure outcomes seen in individuals with glioneuronal tumors. Gross total resection, earlier surgical therapy, and a lack of generalized seizures are common predictors of a favorable seizure outcome. With regard to anticonvulsant medication selection, evidence-based guidelines for the treatment of focal epilepsy should be followed, and individual patient factors should also be considered, including patient age, sex, organ dysfunction, comorbidity, or cotherapy. As concomitant chemotherapy commonly forms an essential part of glioma treatment, enzyme-inducing anticonvulsants should be avoided when possible. Seizure freedom is the ultimate goal in the treatment of brain tumor patients with epilepsy, given the adverse effects of seizures on quality of life.

Seizures in oligodendroglial tumors

Epilepsy develops in more than 70-90% of oligodendroglial tumors and represents a favorable indicator for long-term survival if present as the first clinical sign. Presence of IDH1 mutation is frequently associated with seizures in oligodendrogliomas, next to alterations of glutamate and GABA metabolism in the origin of glioma-associated epilepsy. Treatment by surgery or radiotherapy results in seizure freedom in about two-thirds of patients, and chemotherapy to a seizure reduction in about 50%. Symptomatic anticonvulsive therapy with levetiracetam and valproic acid as monotherapy are both evidence-based drugs for the partial epilepsies, and their effective use in brain tumors is supported by a large amount of additional data. Pharmacoresistance against anticonvulsants is more prevalent among oligodendrogliomas, occurring in about 40% despite polytherapy with two anticonvulsants or more. Toxic signs of anticonvulsants in brain tumors involve cognition, bone marrow and skin. Previous neurosurgery, radiation therapy or chemotherapy add to the risks of cognitive dysfunction.

Seizures and cancer: drug interactions of anticonvulsants with chemotherapeutic agents, tyrosine kinase inhibitors and glucocorticoids

Patients with cancer commonly experience seizures. Combined therapy with anticonvulsant drugs (AEDs) and chemotherapeutic drugs or tyrosine kinase inhibitors carries inherent risks on drug-drug interactions (DDIs). In this review, pharmacokinetic studies of AEDs with chemotherapeutic drugs, tyrosine kinase inhibitors, and glucocorticoids are discussed, including data on maximum tolerated dose, drug clearance, elimination half-life, and organ exposure. Enzyme-inducing AEDs (EIAEDs) cause about a 2-fold to 3-fold faster clearance of concurrent chemotherapeutic drugs metabolized along the same pathway, including cyclophosphamide, irinotecan, paclitaxel, and teniposide, and up to 4-fold faster clearance with the tyrosine kinase inhibitors crizotinib, dasatinib, imatinib, and lapatinib. The use of tyrosine kinase inhibitors, particularly imatinib and crizotinib, may lead to enzyme inhibition of concurrent therapy. Many of the newer generation AEDs do not induce or inhibit drug metabolism, but they can alter enzyme activity by other drugs including AEDs, chemotherapeutics and tyrosine kinase inhibitors. Glucocorticoids can both induce and undergo metabolic change. Quantitative data on changes in drug metabolism help to apply the appropriate dose regimens. Because the large individual variability in metabolic activity increases the risks for undertreatment and/or toxicity, we advocate routine plasma drug monitoring. There are insufficient data available on the effects of tyrosine kinase inhibitors on AED metabolism.

Hydralazine-valproate: a repositioned drug combination for the epigenetic therapy of cancer

INTRODUCTION

DNA methylation (DNMTi) and histone deacetylase inhibitors (HDACi) are in development for cancer therapy. So far, four epigenetic drugs are approved for myelodysplastic syndrome (MDS) and cutaneous T-cell lymphoma (CTCL). The combination of hydralazine-valproate (TRANSKRIP(™)) is being repositioned as an oral DNMT and HDAC inhibitor.

AREAS COVERED

Brief discussion on the current status of epigenetic drugs and studies published on the preclinical and clinical development of the hydralazine-valproate combination.

EXPERT OPINION

Drug repositioning is a strategy for prompt and cost-efficient drug discovery. There is evidence that combining DNMTi with HDACi would be more efficacious than administering each agent on its own. Hydralazine-valproate is safe when used alone or in combination with chemotherapy or chemoradiation. The fact that both drugs are orally administered is another advantage over current epigenetic drugs. This combination is promising but larger studies are needed. Among these, the randomized Phase III trials in advanced and in locally advanced cervical cancer combined with chemotherapy and cisplatin-radiation respectively, would eventually confirm its efficacy. Studies on MDS and CTCL would also eventually prove the efficacy of hydralazine valproate so that in the coming years hydralazine-valproate could have a role in cancer epigenetic therapy.

Histone deacetylase inhibitors in glioblastoma: pre-clinical and clinical experience

Epigenetic mechanisms are increasingly recognized as a major factor contributing to pathogenesis of cancer including glioblastoma, the most common and most malignant primary brain tumour in adults. Enzymatic modifications of histone proteins regulating gene expression are being exploited for therapeutic drug targeting. Over the last decade, numerous studies have shown promising results with histone deacetylase (HDAC) inhibitors in various malignancies. This article provides a brief overview of mechanism of anti-cancer effect and pharmacology of HDAC inhibitors and summarizes results from pre-clinical and clinical studies in glioblastoma. It analyses experience with HDAC inhibitors as single agents as well as in combination with targeted agents, cytotoxic chemotherapy and radiotherapy. Hallmark features of glioblastoma, such as uncontrolled cellular proliferation, invasion, angiogenesis and resistance to apoptosis, have been shown to be targeted by HDAC inhibitors in experiments with glioblastoma cell lines. Vorinostat is the most advanced HDAC inhibitor that entered clinical trials in glioblastoma, showing activity in recurrent disease. Multiple phase II trials with vorinostat in combination with targeted agents, temozolomide and radiotherapy are currently recruiting. While the results from pre-clinical studies are encouraging, early clinical trials showed only modest benefit and the value of HDAC inhibitors for clinical practice will need to be confirmed in larger prospective trials. Further research in epigenetic mechanisms driving glioblastoma pathogenesis and identification of molecular subtypes of glioblastoma is needed. This will hopefully lead to better selection of patients who will benefit from treatment with HDAC inhibitors.

Optimizing antiepileptic drug treatment in tumoral epilepsy

Between 30% and 50% of patients with brain tumors first present with a seizure, and up to 30% more will develop seizures later. Therefore, optimal management of these patients requires a rational approach to the use of antiseizure medications. Based on current evidence, prophylactic prescription of long-term antiepileptic drugs (AEDs) in patients with brain tumors in patients who did not present with seizures is not justified. Because of the high risk of recurrence, however, AED treatment should be strongly considered after a single seizure considered to be due to a tumor. Because of the lack of well-controlled randomized trials, the decision on which AED provides the best risk-benefit ratio in the individual patient is based mostly on physician's judgment rather than sound scientific evidence. In patients who may require chemotherapy, a non-enzyme-inducing AED is preferred for initial treatment to minimize the risk of drug interactions that impact adversely on the outcome of anticancer chemotherapy. Several retrospective studies in seizure patients with glioblastoma treated with chemotherapy have provided evidence for a moderately improved survival with the use of valproic acid, possibly due to inhibition of histone deacetylase. However, valproic acid may also increase the hematologic toxicity of antineoplastic drugs, presumably by inhibiting their metabolism, and may independently impair hemostasis, which is of some concern for patients who require surgical intervention. Among newer generation AEDs, levetiracetam has a number of advantageous features, including availability of a parenteral formulation, but other agents such as gabapentin, lamotrigine, oxcarbazepine, topiramate, and zonisamide may also be considered. Potentially more effective treatments targeting specific mechanisms of epileptogenesis and ictogenesis are being investigated. Resection of the tumor, radiation therapy, or chemotherapy can bring refractory seizures under control or prolong the duration of seizure freedom, an effect that does not appear to be necessarily related to removal or shrinkage of the tumor mass. In patients with a successfully treated tumor and an overall good prognosis for long-term survival, gradual discontinuation of AEDs may be considered.

Drug-drug interaction between methotrexate and levetiracetam resulting in delayed methotrexate elimination

OBJECTIVE

To report a case of delayed methotrexate (MTX) elimination while receiving concomitant levetiracetam.

CASE REPORT

A 46-year-old man with relapsed osteosarcoma of the base of the skull receiving high-dose MTX tolerated his first cycle of MTX with elimination to nontoxic MTX levels (≤0.1 µmol/L) within 90 hours. After hospital discharge, the patient experienced seizures secondary to brain metastasis and started on levetiracetam, which was continued as maintenance therapy. The patient experienced delayed MTX elimination during cycles 2, 3, and 4 while receiving levetiracetam. On average, elimination to nontoxic MTX levels took 130 hours (106-144 hours). Before the fifth cycle of MTX, lorazepam was substituted for the levetiracetam. MTX was eliminated to nontoxic levels within 95 hours. During all cycles, the patient received standard supportive care and serum creatinine remained stable. No other drugs known to interact with MTX were administered.

DISCUSSION

This possible drug interaction has only been reported once in the pediatric population. With a score of 6 on the Drug Interaction Probability Scale for evaluating causation of drug interactions, it is probable that the delayed MTX elimination was caused by an interaction with levetiracetam.

CONCLUSION

Coadministration of levetiracetam and MTX may result in delayed elimination of MTX, increasing the likelihood of toxicity. Consideration should be given to temporarily switching from levetiracetam to another antiepileptic (ie, lorazepam) to prevent this interaction. This is particularly important in those experiencing delayed elimination with prior cycles of concomitant MTX and levetiracetam or those at greater risk for MTX toxicity.

Epilepsy in glioblastoma patients: basic mechanisms and current problems in treatment

Glioblastoma-related epilepsy requires paying careful attention to a combination of factors with an integrated approach. Major interrelated issues must be considered in the seizure care of glioblastoma patients. Seizure control frequently requires the administration of antiepileptic drugs simultaneously with other treatments, including surgery, radiotherapy and chemotherapy, with complete seizure relief often being difficult to achieve. The pharmacological interactions between antiepileptic drugs and antineoplastic agents can modify the activity of both treatments, compromising their efficacy and increasing the probability of developing adverse events related to both therapies. This review summarizes the new pathophysiological pathways involved in the epileptogenesis of glioblastoma-related seizures and the interactions between antiepileptic drugs and oncological treatment, paying special attention to its impact on survival and the current evidence of the antiepileptic treatment efficacy, including the potential usefulness of new third-generation compounds.

Seizures in low-grade gliomas: natural history, pathogenesis, and outcome after treatments

Seizures represent a common symptom in low-grade gliomas; when uncontrolled, they significantly contribute to patient morbidity and negatively impact quality of life. Tumor location and histology influence the risk for epilepsy. The pathogenesis of tumor-related epilepsy is multifactorial and may differ among tumor histologies (glioneuronal tumors vs diffuse grade II gliomas). Gross total resection is the strongest predictor of seizure freedom in addition to clinical factors, such as preoperative seizure duration, type, and control with antiepileptic drugs (AEDs). Epilepsy surgery may improve seizure control. Radiotherapy and chemotherapy with alkylating agents (procarbazine + CCNU+ vincristine, temozolomide) are effective in reducing the frequency of seizures in patients with pharmacoresistant epilepsy. Newer AEDs (levetiracetam, topiramate, lacosamide) seem to be better tolerated than the old AEDs (phenobarbital, phenytoin, carbamazepine), but there is lack of evidence regarding their superiority in terms of efficacy.

Effect of valproic acid on seizure control and on survival in patients with glioblastoma multiforme

BACKGROUND

To examine the efficacy of valproic acid (VPA) given either with or without levetiracetam (LEV) on seizure control and on survival in patients with glioblastoma multiforme (GBM) treated with chemoradiation.

METHODS

A retrospective analysis was performed on 291 patients with GBM. The efficacies of VPA and LEV alone and as polytherapy were analyzed in 181 (62%) patients with seizures with a minimum follow-up of 6 months. Cox-regression survival analysis was performed on 165 patients receiving chemoradiation with temozolomide of whom 108 receiving this in combination with VPA for at least 3 months.

RESULTS

Monotherapy with either VPA or LEV was instituted in 137/143 (95.8%) and in 59/86 (68.6%) on VPA/LEV polytherapy as the next regimen. Initial freedom from seizure was achieved in 41/100 (41%) on VPA, in 16/37 (43.3%) on LEV, and in 89/116 (76.7%) on subsequent VPA/LEV polytherapy. At the end of follow-up, seizure freedom was achieved in 77.8% (28/36) on VPA alone, in 25/36 (69.5%) on LEV alone, and in 38/63 (60.3%) on VPA/LEV polytherapy with ongoing seizures on monotherapy. Patients using VPA in combination with temozolomide showed a longer median survival of 69 weeks (95% confidence interval [CI]: 61.7-67.3) compared with 61 weeks (95% CI: 52.5-69.5) in the group without VPA (hazard ratio, 0.63; 95% CI: 0.43-0.92; P = .016), adjusting for age, extent of resection, and O(6)-DNA methylguanine-methyltransferase promoter methylation status.

CONCLUSIONS

Polytherapy with VPA and LEV more strongly contributes to seizure control than does either as monotherapy. Use of VPA together with chemoradiation with temozolomide results in a 2-months' longer survival of patients with GBM.

Epilepsy meets cancer: when, why, and what to do about it?

The lifetime risk of having epileptic seizures is profoundly increased in patients with cancer: about 20% of all patients with systemic cancer may develop brain metastases. These patients and those with primary brain tumours have a lifetime risk of epilepsy of 20-80%. Moreover, exposure to chemotherapy or radiotherapy to the brain, cancer-related metabolic disturbances, stroke, and infection can provoke seizures. The management of epilepsy in patients with cancer includes diagnosis and treatment of the underlying cerebral pathological changes, secondary prophylaxis with antiepileptic drugs, and limiting of the effect of epilepsy and its treatment on the efficacy and tolerability of anticancer treatments, cognitive function, and quality of life. Because of the concern of drug-drug interactions, the pharmacological approach to epilepsy requires a multidisciplinary approach, specifically in a setting of rapidly increasing choices of agents both to treat cancer and cancer-associated epilepsy.

Brain tumor-related epilepsy

In patients with brain tumor (BT), seizures are the onset symptom in 20-40% of patients, while a further 20-45% of patients will present them during the course of the disease. These patients present a complex therapeutic profile and require a unique and multidisciplinary approach. The choice of antiepileptic drugs is challenging for this particular patient population because brain tumor-related epilepsy (BTRE) is often drug-resistant, has a strong impact on the quality of life and weighs heavily on public health expenditures.In BT patients, the presence of epilepsy is considered the most important risk factor for long-term disability. For this reason, the problem of the proper administration of medications and their potential side effects is of great importance, because good seizure control can significantly improve the patient's psychological and relational sphere. In these patients, new generation drugs such as gabapentin, lacosamide, levetiracetam, oxcarbazepine, pregabalin, topiramate, zonisamide are preferred because they have fewer drug interactions and cause fewer side effects. Among the recently marketed drugs, lacosamide has demonstrated promising results and should be considered a possible treatment option. Therefore, it is necessary to develop a customized treatment plan for each individual patient with BTRE. This requires a vision of patient management concerned not only with medical therapies (pharmacological, surgical, radiological, etc.) but also with emotional and psychological support for the individual as well as his or her family throughout all stages of the illness.

Impact of antiepileptic drugs on thrombocytopenia in glioblastoma patients treated with standard chemoradiotherapy

Epilepsy in glioblastoma multiforme (GBM) patients is common. Hematological toxicity is a potential side effect of antiepileptic drugs (AEDs) and a frequent limiting-dose effect of temozolomide (TMZ). The aim of the study was to investigate the impact of AEDs on thrombocytopenia in GBM patients treated with radiotherapy and TMZ. A cohort of 101 newly diagnosed GBM patients treated with radiotherapy and TMZ was reviewed. Clinical data, presence of seizures, AEDs use, platelet count, and accumulated TMZ dose were analyzed at each cycle. Thrombocytopenia was operationalized as a continuous platelet count and a dichotomic variable (cut-off <100.000/mm(3)). This cut-off represents the threshold beyond which TMZ treatment is modified. A linear and a probit pooled cross-sectional regression analysis were used to study the impact of age, gender, AEDs, and accumulated TMZ on thrombocytopenia. Impact of AEDs on survival was also analyzed. Thirty-five patients (35%) presented seizures at onset and 18 (27%) during follow-up. Seven (13%) needed two or more AEDs for seizure control. Grade 3-4 thrombocytopenia was found in 8%. Decrease in platelet count was related to accumulated TMZ (p < 0.001), age (p < 0.001), and valproate (p = 0.004). Platelet count <100.000/mm(3) was only associated with accumulated TMZ (p = 0.001). Recursive Partitioning Analysis prognostic class was the only variable with significant impact on survival. Valproate and age had an independent negative effect on total platelet count, although neither had an effect on critical thrombocytopenia (<100.000/mm(3)). Therefore, the systematic withhold of valproate in GBM patients might not be justified. Nevertheless, this negative effect may be taken into account especially in elderly patients.

Potential role for valproate in the treatment of high--risk brain tumors of childhood-results from a retrospective observational cohort study

Although substantial progress has been made in pediatric brain tumor management, patients with brainstem tumors and high-grade gliomas, as well as patients less than 3 years of age with high-risk malignant tumors, have a poorer prognosis. The authors have been treating these patients with radiotherapy and standard carboplatin and vincristine chemotherapy. Since January 2007 the authors have been using valproate as anticonvulsant for prophylaxis. The authors performed a retrospective cohort analysis of pediatric patients with high-risk brain tumors treated with chemotherapy, radiotherapy, and valproate prophylaxis, comparing this group with a historical control. The 2007-2008 group was comprised of 22 patients, 15 with brainstem tumors (7 diffuse intrinsic pontine glioma [DIPG], 3 focal, the remaining infiltrating with a solid portion), 4 with diencephalic tumors (2 thalamic), and 3 with supratentorial high-grade tumors (1 glioblastoma, 1 recurrent grade III ependymoma, 1 with gliomatosis). There were 15 patients alive (68%) after a mean follow-up time of 19 months. Survival function comparison by log rank test was highly significant (P = .004) with a hazard ratio of 0.31 (0.14-0.70). Radiological response showed 3 complete responses (14%), 8 partial responses (36%), 5 stable diseases (23%), and 5 progresssive diseases (23%). The authors hypothesize that valproate may have potentiated the antiangiogenic effect of vincristine, diminished expression of resistance to carboplatin, and sensitized tumor cells to radiotherapy. The authors suggest that clinical trials of carboplatin and vincristine associated with oral continuous low-dose valproate are indicated for pediatric patients with high-risk brain tumor.

Prolonged survival with valproic acid use in the EORTC/NCIC temozolomide trial for glioblastoma

OBJECTIVE

This analysis was performed to assess whether antiepileptic drugs (AEDs) modulate the effectiveness of temozolomide radiochemotherapy in patients with newly diagnosed glioblastoma.

METHODS

The European Organization for Research and Treatment of Cancer (EORTC) 26981-22981/National Cancer Institute of Canada (NCIC) CE.3 clinical trial database of radiotherapy (RT) with or without temozolomide (TMZ) for newly diagnosed glioblastoma was examined to assess the impact of the interaction between AED use and chemoradiotherapy on survival. Data were adjusted for known prognostic factors.

RESULTS

When treatment began, 175 patients (30.5%) were AED-free, 277 (48.3%) were taking any enzyme-inducing AED (EIAED) and 135 (23.4%) were taking any non-EIAED. Patients receiving valproic acid (VPA) only had more grade 3/4 thrombopenia and leukopenia than patients without an AED or patients taking an EIAED only. The overall survival (OS) of patients who were receiving an AED at baseline vs not receiving any AED was similar. Patients receiving VPA alone (97 [16.9%]) appeared to derive more survival benefit from TMZ/RT (hazard ratio [HR] 0.39, 95% confidence interval [CI] 0.24-0.63) than patients receiving an EIAED only (252 [44%]) (HR 0.69, 95% CI 0.53-0.90) or patients not receiving any AED (HR 0.67, 95% CI 0.49-0.93).

CONCLUSIONS

VPA may be preferred over an EIAED in patients with glioblastoma who require an AED during TMZ-based chemoradiotherapy. Future studies are needed to determine whether VPA increases TMZ bioavailability or acts as an inhibitor of histone deacetylases and thereby sensitizes for radiochemotherapy in vivo.

Management of provoked seizure

A provoked seizure may be due to structural damage (resulting from traumatic brain injury, brain tumor, stroke, tuberculosis, or neurocysticercosis) or due to metabolic abnormalities (such as alcohol withdrawal and renal or hepatic failure). This article is a part of the Guidelines for Epilepsy in India. This article reviews the problem of provoked seizure and its management and also provides recommendations based on currently available information. Seizure provoked by metabolic disturbances requires correction of the triggering factors. Benzodiazepines are recommended for treatment of seizure due to alcohol withdrawal; gabapentin for seizure seen in porphyria; and antiepileptic drugs (AED), that are not inducer of hepatic enzymes, in the seizures seen in hepatic dysfunction. In severe traumatic brain injury, with or without seizure, phenytoin (PHT) may be given for 7 days. In ischemic or hemorrhagic stroke one may individualize the AED therapy. In cerebral venous sinus thrombosis (CVST), AED may be prescribed if there is seizure or computed tomographic (CT) abnormalities or focal weakness; the treatment, in these cases, has to be continued for 1 year. Prophylactic AED is not recommended in cases of brain tumor and neurosurgical procedures and if patient is on an AED it can be stopped after 1 week.

Antiepileptic drug interactions - principles and clinical implications

Antiepileptic drugs (AEDs) are widely used as long-term adjunctive therapy or as monotherapy in epilepsy and other indications and consist of a group of drugs that are highly susceptible to drug interactions. The purpose of the present review is to focus upon clinically relevant interactions where AEDs are involved and especially on pharmacokinetic interactions. The older AEDs are susceptible to cause induction (carbamazepine, phenobarbital, phenytoin, primidone) or inhibition (valproic acid), resulting in a decrease or increase, respectively, in the serum concentration of other AEDs, as well as other drug classes (anticoagulants, oral contraceptives, antidepressants, antipsychotics, antimicrobal drugs, antineoplastic drugs, and immunosupressants). Conversely, the serum concentrations of AEDs may be increased by enzyme inhibitors among antidepressants and antipsychotics, antimicrobal drugs (as macrolides or isoniazid) and decreased by other mechanisms as induction, reduced absorption or excretion (as oral contraceptives, cimetidine, probenicid and antacides). Pharmacokinetic interactions involving newer AEDs include the enzyme inhibitors felbamate, rufinamide, and stiripentol and the inducers oxcarbazepine and topiramate. Lamotrigine is affected by these drugs, older AEDs and other drug classes as oral contraceptives. Individual AED interactions may be divided into three levels depending on the clinical consequences of alterations in serum concentrations. This approach may point to interactions of specific importance, although it should be implemented with caution, as it is not meant to oversimplify fact matters. Level 1 involves serious clinical consequences, and the combination should be avoided. Level 2 usually implies cautiousness and possible dosage adjustments, as the combination may not be possible to avoid. Level 3 refers to interactions where dosage adjustments are usually not necessary. Updated knowledge regarding drug interactions is important to predict the potential for harmful or lacking effects involving AEDs.

Neurologist vs the neurosurgeons: who is the NICEst? The medical management of the neurosurgical patient with seizures

Seizures and epilepsy are a relatively common occurrence in the neurosurgical patient. Neurosurgeons are often involved in the medical management utilising anti-epileptic drugs (AEDs). There is a distinct lack of contemporary literature in relation to management of seizures/epilepsy in the neurosurgical patient, in particular, for the newer AEDs. In the UK, clinical practice guidelines have been issued from both the National Institute for Health and Clinical Excellence (NICE) and Scottish Intercollegiate Guidelines Network (SIGN) in relation to epilepsy in primary and secondary care. We sought to determine current management practice for neurosurgical patients with epilepsy/seizures. The relevance of the issued guidelines was examined within the neurosurgical setting. An audit by telephone survey was conducted in Neurosurgical and Neurology units in the UK. Respondents were asked about the management of patients in two clinical scenarios. We received 25 responses from the neurosurgical and 22 responses from the neurology communities. Management of the patient scenarios is described and is further considered in relation to the published guidelines. There was considerable disparity between the guidelines and the management strategies pursued by both groups. We conclude that the standard of treatment is sub-optimal in many cases. The guidelines have not had a significant influence and are not felt to be strictly relevant within the neurosurgical setting. The development of guidelines relevant to the neurosurgical setting is proposed. Further research within this field and investment in education for neurosurgeons relating to AED therapy is advocated. The neurologists responses were more closely aligned to the guidelines and so they were deemed the 'NICEst'.

Epilepsy and brain tumors

PURPOSE OF REVIEW

To present an overview of the recent findings in pathophysiology and management of epileptic seizures in patients with brain tumors.

RECENT FINDINGS

Low-grade gliomas are the most epileptogenic brain tumors. Regarding pathophysiology, the role of peritumoral changes [hypoxia and acidosis, blood-brain barrier (BBB) disruption, increase or decrease of neurotransmitters and receptors] are of increasing importance. Tumor-associated epilepsy and tumor growth could have some common molecular pathways. Total/subtotal surgical resection (with or without epilepsy surgery) allows a seizure control in a high percentage of patients. Radiotherapy and chemotherapy as well have a role. New antiepileptic drugs are promising, both in terms of efficacy and tolerability. The resistance to antiepileptic drugs is still a major problem: new insights into pathogenesis are needed to develop strategies to manipulate the pharmakoresistance.

SUMMARY

Epileptic seizures in brain tumors have been definitely recognized as one of the major problems in patients with brain tumors, and need specific and multidisciplinary approaches.

Drug interactions in childhood cancer

Children with cancer are increasingly benefiting from new treatment strategies and advances in supportive care, as shown by improvements in both survival and quality-of-life. However, the continuous emergence of new cancer drugs and supportive-care drugs has increased the possibility of harmful drug interactions; health-care providers need to be very cautious when combining drugs. We discuss the most common interactions between chemotherapeutic drugs and supportive-care drugs-such as anticonvulsants, antiemetics, uric-acid-lowering compounds, acid suppressants, antimicrobials, and pain-management medications in paediatric patients. We also review the interactions between chemotherapy drugs and food and herbal supplements, and provide recommendations to avoid unwanted and potentially fatal interactions in children with cancer. Because of the constant release of new drugs, health-care providers need to check the most recent references before making recommendations about drug interactions.

Interactions between antiepileptic and chemotherapeutic drugs in children with brain tumors: is it time to change treatment?

Epileptic seizures are a common clinical problem in children with brain tumors. The conventional antiepileptic drugs (AEDs) permit a good seizure control in most of these children. An emerging problem is the possible interactions between AEDs and chemotherapeutic drugs, because many of these drugs are metabolized by the cytochrome P450. The aim of this article is to propose a novel therapeutic approach for new-onset epilepsy in children with brain tumors. Among the new AEDs not metabolized by the P450 system, levetiracetam seems to be a promising AED owing to its pharmacokinetic features, efficacy, and safety.

Seizures in patients with low-grade gliomas--incidence, pathogenesis, surgical management, and pharmacotherapy

Seizures complicate the clinical course of > 80% of patients with low-grade gliomas. Patients with some tumor variants almost always have epilepsy. Diffuse low-grade gliomas (LGG) are believed to cause epilepsy through partial deafferentiation of nearby brain cortex (denervation hypersensitivity). Glioneural tumors may interfere with local neurotransmitter levels and are sometimes associated with structural abnormalities of the brain which may produce seizures. The severity of tumor associated epilepsy varies considerably between patients. Some cases may present with a first seizure. Others suffer from long-standing pharmacoresistant epilepsy. Seizure control rates of > 70-80% can be expected after complete tumor resections. Patients with drug-resistant epilepsy require a comprehensive preoperative epileptological work-up which may include the placement of subdural (and intraparenchymal) electrodes or intraoperative electrocorticography (ECoG) for the delineation of extratumoral seizure foci. Partial and subtotal tumor resections are helpful in selected cases, i.e. for gliomas involving the insula. In one series, 40% of patients presented for surgery with uncontrolled seizures, i.e. medical therapy alone often fails to control tumor-related epilepsy. Use of the newer (second generation) non-enzyme inducing antiepileptic drugs (non-EIAED) is encouraged since they seem to have lesser interactions with other medications (e.g. chemotherapy). Chemotherapy and irradiation may have some minor beneficial effects on the patients' seizure disorder. Overall 60-70% of patients may experience recurrent epilepsy during long-term follow-up. Recurrent seizures (not infrequently heralding tumor recurrence) after surgery continue to pose significant clinical problems.

Epilepsy and insular Grade II gliomas: an interdisciplinary point of view from a retrospective monocentric series of 46 cases

OBJECT

There are few data in the literature concerning a multimodal approach to insular WHO Grade II gliomas (GIIGs) and the control of epilepsy after treatment. In this paper, the authors describe a monocentric series of 46 cases in which patients underwent various sequential treatments for insular GIIGs. On the basis of global results with regard to epilepsy, the respective interests in the various treatments are discussed.

METHODS

Available data on 46 patients harboring insular GIIGs were extracted from a local database of 288 GIIGs. The various therapeutic sequences were analyzed in parallel with the course of seizure frequency.

RESULTS

Despite the usual difficulties with seizure quantification in retrospective studies, the authors showed that 1) the negative course of seizure frequency was mostly connected to tumor progression, 2) surgery almost always had a favorable effect on epilepsy, and 3) chemotherapy had a mostly favorable effect with acceptable tolerance. The authors were unable to draw conclusions about the role of radiotherapy given the too few cases.

CONCLUSIONS

This extensive experience with insular GIIGs tends to confirm interest in their surgical removal and supports interest in chemotherapy from an epileptological point of view.

Management of epilepsy in oncological patients

INTRODUCTION

Comorbidity between epilepsy and cancer is elevated. As a life-time condition, it is not impossible for a patient with epilepsy to have a cancer at some point. Besides, at least 30% of patients with primary brain tumors have epileptic seizures, but also in patients with metastatic infiltrating lesions of the central nervous system and with extracerebral tumors, epilepsy can be related. Seizures may also appear associated with paraneoplastic syndromes, such as limbic encephalitis and metabolic and infectious complications of chemotherapy and radiotherapy.

RESULTS

The precise mechanisms by which brain tumors and the other conditions mentioned above produce seizures are not fully understood, but are reviewed in this article, as well as the many different therapeutic options that may be used in the treatment of epileptic seizures. Pharmacological treatment poses various controversies, such as the utility of prophylactic treatment, interactions between antiepileptic drugs (AEDs) and chemotherapeutic drugs and the complications derived from the adverse effects of AEDs in this population. Finally, other treatments are proposed such as chemotherapy, radiotherapy and surgery, the rational application of which allows for an improvement in the patients' quality of life.

CONCLUSION

In order to arrive at a diagnosis, the different causes that could condition the appearance of epileptic seizures in cancer patients must be known. After this, the most adequate treatment should be chosen, thus ensuring the comprehensive treatment of cancer and epilepsy.