Fenfluramine for Treating Dravet Syndrome: An Evidence Review Group Perspective of a NICE Single Technology Appraisal.

Fenfluramine, tradename Fintepla®, was appraised within the National Institute for Health and Care Excellence (NICE) single technology appraisal (STA) process as Technology Appraisal 808. Within the STA process, the company (Zogenix International) provided NICE with a written submission and a mathematical health economic model, summarising the company's estimates of the clinical effectiveness and cost-effectiveness of fenfluramine for patients with Dravet syndrome (DS). This company submission (CS) was reviewed by an evidence review group (ERG) independent of NICE. The ERG, Kleijnen Systematic Reviews in collaboration with Maastricht University Medical Centre, produced an ERG report. This paper presents a summary of the ERG report and the development of the NICE guidance. The CS included a systematic review of the evidence for fenfluramine. From this review the company identified and presented evidence from two randomised trials (Study 1 and Study 1504), an open-label extension study (Study 1503) and 'real world evidence' from a prospective and retrospective study. Both randomised trials were conducted in patients up to 18 years of age with DS, whose seizures were incompletely controlled with previous anti-epileptic drugs. A Bayesian network meta-analysis was performed to compare fenfluramine with cannabidiol plus clobazam. There was no evidence of a difference between any doses of fenfluramine and cannabidiol in the mean convulsive seizure frequency (CSF) rate during treatment. However, fenfluramine increased the number of patients achieving ≥ 50% reduction in CSF frequency from baseline compared to cannabidiol. The company used an individual-patient state-transition model (R version 3.5.2) to model cost-effectiveness of fenfluramine. The CSF and convulsive seizure-free days were estimated using patient-level data from the placebo arm of the fenfluramine registration studies. Subsequently, a treatment effect of either fenfluramine or cannabidiol was applied. Utility values for the economic model were obtained by mapping Pediatric Quality of Life Inventory data from the registration studies to EuroQol-5D-3L Youth (EQ-5D-Y-3L). The company included caregiver utilities in their base-case, as the severe needs of patients with DS have a major impact on parents and caregivers. There were several key issues. First, the company included caregiver utilities in the model in a way that when patients in the economic model died, the corresponding caregiver utility was also set to zero. Second, the model was built in R statistical software, resulting in transparency issues. Third, the company assumed the same percentage reduction for convulsive seizure days as was estimated for CSF. Fourth, during the final appraisal committee meeting, influential changes were made to the model that were not in line with the ERG's preferences (but were accepted by the appraisal committee). The company's revised and final incremental cost effectiveness ratio (ICER) in line with committee preferences resulted in fenfluramine dominating cannabidiol. Fenfluramine was recommended as an add-on to other antiepileptic medicines for treating seizures associated with DS in people aged 2 years and older in the National Health Service (NHS).

Nordic treatment guidelines for rare epileptic conditions: A literature review.

INTRODUCTION: The onset of severe, drug-resistant seizures in early childhood is characteristic of the rare epileptic disorders Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and CDKL5 deficiency disorder (CDD) and is frequently observed in the rare genetic conditions tuberous sclerosis complex (TSC) and Rett syndrome (RTT). High-quality treatment guidelines are needed for optimal management of these conditions. This review aimed to assess content, availability, and development of treatment guidelines for these disorders in the Nordics region (Denmark, Finland, Iceland, Norway, and Sweden). METHODS: A targeted literature review (TLR) was therefore conducted in November/December 2020 by manually searching online rare disease and guideline databases in addition to relevant health technology assessment and regulatory agency websites to identify pharmacological treatment guidelines for DS, LGS, TSC, RTT, and CDD. Search terms for each disorder were translated to identify country-specific guidelines. Treatment recommendations, geographical focus, and guideline development methodology was extracted into a predetermined extraction grid. RESULTS: Most of the 24 eligible guidelines identified (16/24; 66%) were specific to particular countries; Sweden was the most represented (7/24 [29%] guidelines), while no guidelines were identified for Iceland. Guideline development methodologies were heterogeneous, including systematic literature reviews/TLRs and expert consultation; several methodologies did not report details on the evidence sources used (7/24 [29%] guidelines). Treatment recommendation availability was variable across disorders, ranging from 126 treatment recommendations (LGS) to none (RTT, CDD). CONCLUSION: Comprehensive, consensus-based treatment guidance developed via international collaboration within the Nordics region is necessary to optimize patient care in these five rare epileptic conditions.

The contribution of fenfluramine to the treatment of Dravet syndrome in Spain through Multi-Criteria Decision Analysis.

INTRODUCTION: Dravet Syndrome (DS) is a severe, developmental epileptic encephalopathy (DEE) that begins in infancy and is characterized by pharmaco-resistant epilepsy and neurodevelopmental delay. Despite available antiseizure medications (ASMs), there is a need for new therapeutic options with greater efficacy in reducing seizure frequency and with adequate safety and tolerability profiles. Fenfluramine is a new ASM for the treatment of seizures associated with DS as add-on therapy to other ASMs for patients aged 2 years and older. Fenfluramine decreases seizure frequency, prolongs periods of seizure freedom potentially helping to reduce risk of Sudden Unexpected Death in Epilepsy (SUDEP) and improves patient cognitive abilities positively impacting on patients' Quality of Life (QoL). Reflective Multi-Criteria Decision Analysis (MCDA) methodology allows to determine what represents value in a given indication considering all relevant criteria for healthcare decision-making in a transparent and systematic manner from the perspective of relevant stakeholders. The aim of this study was to determine the relative value contribution of fenfluramine for the treatment of DS in Spain using MCDA. METHOD: A literature review was performed to populate an adapted a MCDA framework for orphan-drug evaluation in Spain. A panel of ten Spanish experts, including neurologists, hospital pharmacists, patient representatives and decision-makers, scored four comparative evidence matrices. Results were analyzed and discussed in a group meeting through reflective MCDA discussion methodology. RESULTS: Dravet syndrome is considered a severe, rare disease with significant unmet needs. Fenfluramine is perceived to have a higher efficacy profile than all available alternatives, with a better safety profile than stiripentol and topiramate and to provide improved QoL versus studied alternatives. Fenfluramine results in lower other medical costs in comparison with stiripentol and clobazam. Participants perceived that fenfluramine could lead to indirect costs savings compared to available alternatives due to its efficacy in controlling seizures. Overall, fenfluramine's therapeutic impact on patients with DS is considered high and supported by high-quality evidence. CONCLUSIONS: Based on reflective MCDA, fenfluramine is considered to add greater benefit in terms of efficacy, safety and QoL when compared with available ASMs.

Patient and Caregiver Health State Utilities in Lennox-Gastaut Syndrome and Dravet Syndrome.

PURPOSE: Lennox-Gastaut syndrome (LGS) and Dravet syndrome (DS) are rare, treatment-resistant forms of epilepsy characterized by childhood onset of seizures. Cost-effectiveness analysis for new antiseizure medications typically requires health state utilities (HSUs) that reflect the patient and caregiver burden of the relevant conditions. This study aimed to estimate HSUs for LGS and DS. Focus was placed on valuing the impact of seizure frequency and seizure-free days on health-related quality of life (HRQL) for patients and caregivers. METHODS: Health state vignettes that described the experience of living with and caring for a child with LGS or DS were developed based on a targeted literature review and feedback from interviews with LGS and DS clinical experts and DS caregivers. Vignettes varied by the number of seizures and seizure-free days per month. Twenty-four vignettes were developed that described patient HRQL (6 per condition) and caregiver HRQL (6 per condition) for LGS or DS. Vignettes were evaluated via interviews from the general population in the United Kingdom and Sweden using a visual analog scale and time trade-off (TTO) method. Participants were recruited by interviewers based in different regions of the United Kingdom and Sweden using convenience sampling. FINDINGS: Two hundred interviews were conducted by video call from March to April 2020. One hundred participants evaluated each of the 6 patient and 6 caregiver vignettes for LGS; a different 100 participants evaluated each of the DS vignettes. The estimated utility values vary consistently according to seizure frequency and number of seizure-free days. Patient TTO utility values range from -0.186 (highest seizure frequency and fewest seizure-free days) to 0.754 (seizure-free state) for LGS and from 0.171 to 0.778 for DS. The caregiver TTO utility values range from 0.032 to 0.810 and 0.510 to 0.881 for LGS and DS, respectively. Fewer seizures and additional seizure-free days are associated with better patient and caregiver HRQL. IMPLICATIONS: This study estimated utility values for patients with LGS or DS and their caregivers using visual analog scale and TTO valuation among a general public sample. These utility values can be used in cost-effectiveness assessments of new antiseizure medications. The findings indicate the importance of seizure-free days as well as seizure frequency in patient and caregiver HRQL, which may inform the design of future clinical trials.

Economic Evaluation of Cannabinoid Oil for Dravet Syndrome: A Cost-Utility Analysis.

INTRODUCTION: Cannabinoid oils are being increasingly used to treat Dravet syndrome, yet the long-term costs and outcomes of this approach are unknown. Thus, we examined the cost effectiveness of cannabinoid oil as an adjunctive treatment (added to clobazam and valproate), compared with adjunctive stiripentol or with clobazam and valproate alone, for the treatment of Dravet syndrome in children. METHODS: We performed a probabilistic cost-utility analysis from the perspective of the Canadian public health care system, comparing cannabinoid oil and stiripentol (both on a background of clobazam and valproate) with clobazam and valproate alone. Costs and quality-adjusted life-years (QALYs) were estimated using a Markov model that followed a cohort of children aged from 5 to 18 years through model states related to seizure frequency. Model inputs were obtained from the literature. The cost effectiveness of adjunctive cannabinoid oil, adjunctive stiripentol, and clobazam/valproate alone was assessed through sequential analysis. The influence of perspective and other assumptions were explored in scenario analyses. All costs are expressed in 2019 Canadian dollars, and costs and QALYs were discounted at a rate of 1.5% per year. RESULTS: The incremental cost per QALY gained with the use of adjunctive cannabinoid oil, from the health care system perspective, was $32,399 compared with clobazam and valproate. Stiripentol was dominated by cannabinoid oil, producing fewer QALYs at higher costs. At a willingness-to-pay threshold of $50,000, cannabinoid oil was the optimal treatment in 76% of replications. From a societal perspective, cannabinoid oil dominated stiripentol and clobazam/valproate. The interpretation of the results was insensitive to model and input assumptions. CONCLUSION: Compared with clobazam/valproate, adjunctive cannabinoid oil may be a cost-effective treatment for Dravet syndrome, if a decision maker is willing to pay at least $32,399 for each QALY gained. The opportunity costs of continuing to fund stiripentol, but not cannabinoid oil, should be considered.

[Analysis of the family impact and needs of Dravet's syndrome in Spain]. / Análisis del impacto familiar y necesidades del síndrome de Dravet en España.

INTRODUCTION: Dravet's syndrome (DS) is an epileptic encephalopathy that starts in infancy and has an important impact on the lives of patients and their relatives. There is currently a need for improvement in diagnosis and treatment: two drugs have been approved for the treatment of DS in Europe, although new treatments are under development or are scheduled for commercialisation soon. AIMS: To understand the situation of DS in Spain and to identify opportunities for improvement. SUBJECTS AND METHODS: The study will involve an analysis of data from a European macro-survey in which carers of patients with DS expressed their experience with the disease. RESULTS: Data from 57 families with children with DS (mean age: 9 years). The time to diagnosis, usually after another misdiagnosis (80%), increases in older patients (80% of adults: diagnostic delay > 4 years). The delay induces an increased use of contraindicated antiepileptic drugs. Seizures (87% of cases; the most frequent, tonic-clonic: 90%) and hospitalisations (60% of cases) continue into adulthood. The severity of the illness and the number of hospitalisations correlate with impact on caregivers and family. The effectiveness of treatments and the future of patients are the greatest concerns. CONCLUSIONS: In order to improve the management and quality of life of patients with DS and their families, it is necessary to have an early diagnosis and to incorporate new treatments that help to control the epileptic seizures and the comorbidities of the disease.

TITLE: Análisis del impacto familiar y necesidades del síndrome de Dravet en España.Introducción. El síndrome de Dravet (SD) es una encefalopatía epiléptica, iniciada en la infancia, con un gran impacto en la vida de los pacientes y los familiares. Actualmente se necesitan mejoras en su diagnóstico y tratamiento: existen dos fármacos aprobados para el tratamiento del SD en Europa, aunque hay nuevos tratamientos en desarrollo o en vías de comercialización próximamente. Objetivos. Comprender la situación del SD en España e identificar las oportunidades de mejora. Sujetos y métodos. Análisis de los datos de una macroencuesta europea en la que los cuidadores de pacientes con SD manifestaron su experiencia con la enfermedad. Resultados. Datos de 57 familias con hijos con SD (edad media: 9 años). El tiempo hasta el diagnóstico, generalmente tras otro erróneo (80%), se incrementa en los pacientes de mayor edad (el 80% de los adultos: retraso diagnóstico > 4 años). La demora induce un mayor uso de fármacos antiepilépticos contraindicados. Las crisis (87% de los casos; las más frecuentes, tonicoclónicas: 90%) y las hospitalizaciones (60% de los casos) continúan hasta la edad adulta. La gravedad de la enfermedad y el número de hospitalizaciones se correlacionan con el impacto en los cuidadores y la familia. La eficacia de los tratamientos y el futuro de los pacientes son las mayores preocupaciones. Conclusiones. Para mejorar el manejo y la calidad de vida de los pacientes con SD y los familiares, es necesario un diagnóstico temprano y la incorporación de nuevos tratamientos que ayuden al control de las crisis epilépticas y de las comorbilidades de la enfermedad.

Ascertaining the epidemiology, patient flow and disease management for Dravet syndrome in Spain. / Determinacion de la epidemiologia, el flujo de pacientes y el tratamiento del sindrome de Dravet en España.

INTRODUCTION: Dravet syndrome (DS) is a rare, drug resistant epilepsy that starts very early in life with febrile seizures followed by cognitive impairment and diverse seizure types. AIM: To generate evidence on the epidemiology of DS, its diagnosis, patient-flow, treatment and unmet needs from the perspective of Spanish experts. DEVELOPMENT: A two-round Delphi study involving 19 physicians was conducted. Questionnaires were based on literature review and validated by clinical experts. Consensus was reached when topics were subject to routine clinical practice and individual experience, or the coefficient of variation among answers was <= 0.3. The estimated number of new DS patients is 73 per year. Prevalence is estimated to be between 348-540 patients. DS is mostly diagnosed in children. Survival varies from 5 to 60 years. There is no standardised follow-up of patients beyond the age of 18 and mortality rates are uncertain. No standard guidelines exist for diagnosing or treating DS. It takes 9 to 15 months to confirm the diagnosis and genetic testing is unevenly available. Valproic acid, clobazam, stiripentol and topiramate are commonly used. Poor efficacy and safety are the main reasons for treatment switch. CONCLUSIONS: The epidemiology of DS in Spain is not well known and several areas of unmet needs still exist. Experts' views offer a starting point for further research into the reality of DS in Spain. Epidemiological studies, consensus criteria, easy access to genetic testing, treatment options, training and research into quality of life aspects are highly needed.

TITLE: Determinacion de la epidemiologia, el flujo de pacientes y el tratamiento del sindrome de Dravet en España.Introduccion. El sindrome de Dravet (SD) es una epilepsia rara y resistente a los farmacos que comienza en etapas muy precoces de la vida con convulsiones febriles, seguidas de deterioro cognitivo y diversos tipos de crisis epilepticas. Objetivo. Generar datos objetivos sobre la epidemiologia del SD, su diagnostico, el flujo de pacientes, el tratamiento y las necesidades no cubiertas desde el punto de vista de expertos españoles. Desarrollo. Se efectuo un estudio Delphi de dos rondas en el que participaron 19 medicos. Los cuestionarios se basaron en una revision de la bibliografia y fueron validados por expertos clinicos. Se alcanzo consenso si los temas se referian a la practica clinica habitual y la experiencia individual, o si el coeficiente de variacion entre las respuestas era <= 0,3. El numero estimado de pacientes nuevos con SD es de 73 al año. La prevalencia se calcula entre 348 y 540 pacientes. El SD se diagnostica principalmente en niños. La supervivencia varia entre los 5 y los 60 años. No existe ningun seguimiento normalizado para los pacientes de mas de 18 años de edad, y las tasas de mortalidad son inciertas. No existen guias normalizadas para diagnosticar o tratar el SD. Se tarda de 9 a 15 meses en confirmar el diagnostico, y la disponibilidad de los analisis geneticos es irregular. Normalmente se utilizan el acido valproico, el clobazam, el estiripentol y el topiramato. La escasa eficacia y la seguridad son los motivos principales de los cambios de tratamiento. Conclusiones. La epidemiologia del SD en España es poco conocida, y sigue habiendo necesidades no cubiertas en algunas areas. Las opiniones de expertos suponen un punto de partida para poder investigar la realidad del SD en España. Los estudios epidemiologicos, los criterios de consenso, el acceso facil a las pruebas geneticas, las opciones de tratamiento, la formacion y la investigacion de la calidad de vida relacionada con la salud constituyen todos ellos aspectos muy necesarios.

Economic Evaluation of Stiripentol for Dravet Syndrome: A Cost-Utility Analysis.

BACKGROUND: Dravet syndrome is a catastrophic form of pediatric treatment-resistant epilepsy with few effective treatment options. Stiripentol is approved for use in Canada for treatment of Dravet syndrome, but the associated long-term costs and benefits have not been well-studied and its cost effectiveness is unclear. OBJECTIVE: The aim of this study was to evaluate the cost effectiveness of stiripentol as an adjunctive treatment to clobazam and valproate for treatment of Dravet syndrome from the perspective of the Canadian public healthcare payer. METHODS: A cost-utility analysis was performed to estimate the costs and quality-adjusted life-years (QALYs) associated with adjunctive stiripentol treatment compared with clobazam and valproate alone in children with Dravet syndrome. Transition probabilities, drug efficacy, utility weights, and costs were obtained from a review of the literature. Probabilistic analyses were conducted using a Markov model with health states related to seizure frequency. A 10-year horizon was used. The incremental cost per QALY gained (incremental cost-effectiveness ratio [ICER]) for adjunctive use of stiripentol was calculated, and assumptions were explored in scenario analyses. All costs are expressed in 2017 Canadian dollars ($Can). RESULTS: Compared with clobazam and valproate alone, the adjunctive use of stiripentol is associated with an ICER of $Can151,310. At a willingness-to-pay threshold of $Can50,000, the probability that stiripentol was the optimal treatment was 5.2%. The cost of stiripentol would need to be reduced by 61.4% for stiripentol to be cost effective. CONCLUSION: From the perspective of the Canadian public healthcare payer, stiripentol is not cost effective at its current price at a willingness-to-pay threshold of $Can50,000. Funding stiripentol will be associated with important opportunity costs that bear consideration.

Levetiracetam como terapia adjuvante em pacientes com epilepsia mioclônica juvenil resistentes à monoterapia / Levetiracetam as adjuvant therapy in patients with juvenile myoclonic epilepsy resistant to monotherapy

CONTEXTO: A epilepsia é uma doença cerebral crônica caracterizada pela recorrência de crises epilépticas não provocadas. Conforme Protocolo Clínico e Diretrizes Terapêuticas (PCDT) vigente do Ministério da Saúde (MS), o tratamento disponível no Sistema Único de Saúde (SUS) inclui os agentes antiepilépticos fenobarbital, fenitoína, primidona, topiramato, lamotrigina, carbamazepina e valproato de sódio. As epilepsias idiopáticas generalizadas são classificadas como síndromes epilépticas. A EMJ é a mais comum dentre as síndromes da adolescência e uma das mais frequentemente diagnosticadas. A maioria dos pacientes com EMJ apresentam bom controle do quadro clínico com a utilização do valproato de sódio em monoterapia, mas na falha ou impossibilidade de seu uso, fármacos como a lamotrigina e o levetiracetam podem ser utilizados. TECNOLOGIA: levetiracetam (Keppra®). INDICAÇÃO: Terapia adjuvante, ou seja em associação com o valproato de sódio, em pacientes com epilepsia mioclônica juvenil (EMJ) resistentes à monoterapia. PERGUNTA: O uso do levetiracetam em regime de terapia adjuvante, é eficaz, seguro e custoefetivo em relação à continuação da monoterapia em pacientes com epilepsia mioclônica juvenil, resistentes a outros agentess antiepilépticos na perspectiva do SUS? EVIDÊNCIAS CIENTÍFICAS: A evidência da utilização do levetiracetam associado à tratamento prévio com um agente antiepiléptico para o tratamento da EMJ é baseada em um ensaio clínico duplo-cego que apresentou redução significante de 50% no número de dias por semana com crises convulsivas s (OR = 4,77; IC 95% 2,12 ­ 10,77; p<0,0001 e um maior número de pacientes, que receberam levetiracetam, apresentaram ausência total de crises durante o tratamento (16,7% dos pacientes, p = 0,03, vs 3,3 % do grupo que recebeu placebo). AVALIAÇÃO ECONÔMICA: Foi apresentado um modelo de custo-efetividade comparando a monoterapia com ácido valpróico ao tratamento adjuvante do levetiracetam (associado) ao ácido valpróico. Foi elaborado um modelo baseado primeiramente em uma árvore de decisão, seguido por um modelo de Markov. No caso-base a razão de custo-utilidade incremental (RCUI) foi de R$ 58.294 por ano de vida ajustada pela qualidade, que na análise de sensibilidade univariada variou entre R$ 22.119 e R$ 80.359. Avaliação de Impacto Orçamentário: Conforme as estimativas feitas pelo demandante o impacto orçamentário será de aproximadamente R$ 1,58 milhão no primeiro ano e de R$ 43,6 milhões nos primeiros 5 anos após a incorporação. Na análise de sensibilidade realizada o impacto orçamentário para os próximos 5 anos variou entre R$ 14,5 e R$ 87,3 milhões. EXPERIÊNCIA INTERNACIONAL: o levetiracetam é utilizado em terapia adjuvante para o tratamento de crises mioclônicas em agências como o National Institute for Health and Clinical Excellence (NICE) e Canadian Agency for Drugs and Technologies in Health (CADTH), de acordo com condições estabelecidas Discussão: A evidência do tratamento com levetiracetam em pacientes resistentes à monoterapia padrão, associado ao medicamento já utilizado, ocasionou em redução significante de pelo menos 50% no número de dias por semana com crises convulsivas e um maior número de pacientes apresentaram ausência total de crises convulsivas durante seu período de seguimento. Porém trata-se de evidência indireta e de baixa qualidade. Os estudos para essa indicação da tecnologia são escassos e há baixa probabilidade de novos estudos serem realizados. A avaliação econômica foi custo-efetiva na adição do levetiracetam ao medicamento previamente utilizado em monoterapia, em pacientes resistentes, com um impacto orçamentário de até R$ 87,3 milhões em 5 anos, de acordo com a análise de sensibilidade. A secretaria executiva da CONITEC estimou o número de pacientes, que considera mais adequada para o cálculo, que foi 7,8% maior que a população considerada na análise do demandante, o que levaria a um impacto orçamentário ainda maior. RECOMENDAÇÃO DA CONITEC: A CONITEC em sua 54ª reunião no dia 06 de abril de 2017, recomendou preliminarmente a incorporação no SUS do levetiracetam como terapia adjuvante em pacientes com epilepsia mioclônica juvenil resistentes à monoterapia, condicionada à redução de preço e consonância com a atualização do PCDT de Epilepsia. Consulta pública: Foi realizada a Consulta Pública nº 22/2017, entre os dias 25/04/2017 e 16/05/2017 e recebeu 105 contribuições, sendo 88 sobre experiência ou opinião e 17 técnicocientíficas. Todas as contribuições foram avaliadas quantitativamente e qualitativamente. Seu conteúdo não trouxe novas evidências e informações que pudessem modificar a recomendação inicial da CONITEC. DELIBERAÇÃO FINAL: Os membros da CONITEC presentes na 56ª reunião ordinária do plenário do dia 07/06/2017 deliberaram, por unanimidade, por recomendar a incorporação do levetiracetam para pacientes com epilepsia mioclônica juvenil (EMJ) resistentes à monoterapia, associando-o ao medicamento já utilizado, condicionado à negociação de preço e conforme Protocolo Clínico e Diretrizes Terapêuticas do Ministério da Saúde. Foi assinado o Registro de Deliberação nº 264/2017.(AU)

Evaluation of health-care utilization in patients with Dravet syndrome and on adjunctive treatment with stiripentol and clobazam.

Dravet syndrome (DS) is a rare, severe childhood epilepsy syndrome that imposes a substantial burden on patients and their caregivers. This study evaluated health-care utilization over a 2-year period in patients with DS at an outpatient clinic of a German epilepsy center. Data on the course of epilepsy, anticonvulsant treatment, and direct costs were recorded using the electronic seizure diary Epivista and patients' files. We enrolled 13 patients with DS (6 females, mean age: 12.3±7.5 years) between 2007 and 2010 and evaluated them during a 1-year baseline. All patients had drug-resistant epilepsy and their seizures failed to improve with a mean number of 6.7±3.4 anticonvulsants. They had an overall mean seizure frequency of 102.1 seizures per year (median: 31, range: 3-538) with 43.2 GTCSs per year (median: 14, range: 0-228). We estimated the annual total direct costs at €6506±3974 (range: €1174-11,783) per patient with hospitalization (68.9% of total direct costs) as the major cost factor ahead of costs for anticonvulsants (24.0%). For the 1-year follow-up period, less severely affected patients were continued on conventional anticonvulsants (n=4) or switched to adjunctive treatment with stiripentol and clobazam (n=9). In the latter group, six patients (67%) were long-term responders, with between 25% and 100% seizure reduction with respect to either GTCSs or the overall seizure frequency. This reduction in seizure frequency was associated with a shift in the distribution of cost components towards higher medication costs and decreased hospitalization costs. The total direct costs increased by 42.7%, mainly due to the newly introduced stiripentol, with an annual cost of €6610. This study showed that direct costs of patients with DS were above the average European costs of drug-resistant epilepsy in children. Treatment with new anticonvulsants resulted in reduction of seizures and inpatient admissions.

Development of new treatment approaches for epilepsy: unmet needs and opportunities.

A working group was created to address clinical "gaps to care" as well as opportunities for development of new treatment approaches for epilepsy. The working group primarily comprised clinicians, trialists, and pharmacologists. The group identified a need for better animal models for both efficacy and tolerability, and noted that animal models for potential disease-modifying or antiepileptogenic effect should mirror conditions in human trials. For antiseizure drugs (ASDs), current animal models have not been validated with respect to their relationship to efficacy in common epilepsy syndromes. The group performed an "expert opinion" survey of perceived efficacy of the available ASDs, and identified a specific unmet need for ASDs to treat tonic-atonic and myoclonic seizures. No correlation has as yet been demonstrated between animal models of tolerability and adverse effects (AEs), versus tolerability in humans. There is a clear opportunity for improved therapies in relation to dose-related AEs. The group identified common and rare epilepsy syndromes that could represent opportunities for clinical trials. They identified opportunities for antiepileptogenic (AEG) therapies in both adults and children, acknowledging that the presence of a biomarker would substantially improve the chances of a successful trial. However, the group acknowledged that disease-modifying therapies (given after the first seizure or after the development of epilepsy) would be easier to study than AEG therapies.

Preclinical assessment of proconvulsant drug activity and its relevance for predicting adverse events in humans.

Safety pharmacology studies, which are performed before first studies with investigational drugs in humans, often include experiments on proconvulsant drug activity, because such drugs are thought to promote seizures by decreasing seizure threshold. A commonly used model for the assessment of proconvulsant activity of investigational or marketed drugs is the timed intravenous pentylenetetrazole (PTZ) infusion seizure test, in which the latency to myoclonic or clonic seizures is determined by PTZ infusion in mice or rats. This test provides an extremely sensitive parametric method for assessing seizure threshold and allows detecting both anticonvulsant and proconvulsant drug effects. The aim of this review is to critically review the concept of "proconvulsant" drug activity and discuss data obtained by the PTZ and other seizure threshold tests as well as the various factors that may affect seizure threshold determinations. Furthermore, preclinical and clinical data on proconvulsant drug activity are compared. It is concluded that a battery of different tests is needed to provide the most reliable conclusions about the proconvulsant profile, if any, of drugs. Furthermore, misconceptions regarding proconvulsant drug effects, which can result in the undertreatment of brain diseases, are discussed.

Valproate-induced metabolic changes in patients with epilepsy: assessment with H-MRS.

PURPOSE: Valproate (VPA) interferes with mitochondrial metabolism causing hyperammonemia, thereby shifting the balance reaction of glutamine (Gln)/glutamate (Glu) toward Gln. In this study we wanted to determine whether metabolic changes could be reproduced in VPA-treated patients with epilepsy and whether the results differed from those known in chronic hepatic encephalopathy (CHE). METHODS: Seven patients with epilepsy pretreated with VPA and seven healthy volunteers were investigated on a 3T-scanner. We performed proton magnetic resonance spectroscopy ((1)H-MRS) using a short echo time point-resolved spectroscopy (PRESS) in the parietal and occipital lobe, respectively. Spectral analysis was performed by LCModel, allowing a separation of Glu and Gln at 3T. Absolute values of myo-Inositol (mI), choline (Cho), creatine (Cr), N-acetyl-aspartate (NAA), glutamine (Gln), glutamate (Glu), and the sum of Gln and Glu (Glx) were calculated. RESULTS: In the parietal lobe, mI was significantly decreased in the patients' group compared to the healthy volunteers. After separation of the signals of Gln and Glu, a significant increase of Gln was observed in the parietal lobe in the patients' group. No significant differences in the occipital spectra could be observed between the groups. DISCUSSION: In VPA-treated patients the alteration of the Glu/Gln ratio differs from that in patients with CHE, where Glx is markedly increased because of an increase in Gln. The expected shift from the biochemical balance reaction of Gln/Glu induced by VPA could be reproduced for the parietal lobe. Significantly reduced mI in the parietal lobe of VPA-treated patients most likely reflects an osmolytic compensation for high Gln.