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The Context of the IOM Study on the Epilepsies
Frances E. Jensen, MDProfessor of Neurology, Harvard Medical School
Co‐Chair, Vision 20‐20
Vice President and President‐elect, American Epilepsy Society
January 10, 2011
Epilepsy ἐπιληψία (epilēpsía) — "to seize")
• Episodic, unpredictable alteration in neurologic status– Ranging from mild motor to severe prolonged generalized convulsion
– Profound effects on patient and family’s medical, social, academic, and financial status
– Can be lethal
– Highly stigmatized
EPILEPSY IS COMMON
• Existing statistics reveal up to 3 million people in the US suffer from epilepsy– 50 million worldwide
• Highest incidence of new cases at the 2 ends of life
• Population segments that have been least surveyed in prior studies
• Prevalence changing as population ages– Increase in elderly, returning veterans
• 1 in 10 people will have a seizure in their lifetime– Lifetime risk of epilepsy (recurrent seizures) is 3.3%
…but often hidden
Incidence of Epilepsy by Age— Composite of 12 Studies in Developed Countries, 1988‐2005
Courtesy David Thurman
Epilepsy Spectrum Disorder
• Spectrum of seizure syndromes• Spectrum of etiologies• Spectrum of severity• Spectrum of non‐ictal symptoms
SEIZURES
Attention Cognitive Psychiatric Dementia Mental SUDEPdeficit deficits disorders retardation
NINDS Epilepsy Benchmarks Area III: Prevent, limit, and reverse the co‐morbidities associated with epilepsy and its treatment.
http://www.ninds.nih.gov/research/epilepsyweb/2007_benchmarks.htm
• Seizures are the tip of the iceberg
• Neurobiology of epileptogenesis is shared with the pathophysiology of “non‐ictal” symptoms (comorbidities)– Developmental disorders– Cognitive impairment, attention deficits– Psychiatric disorders– SUDEP
• Implications for diagnosis and treatment beyond the seizures
Epilepsy in 2011
• Ideal time for an IOM study: Our field is poised for advancement
• Explosion of new information from basic and clinical neurosciences redefining this disease
• Inadequate assessment of populations at risk, incidence, prevalence, with wider definition of the disease
• Complex therapeutic landscape emerging– Pharmacologic, nutritional, surgical and device‐driven– Pipeline is a problem from T1 to T4– No cure yet, only symptom suppression at best
• Problematic delivery of care to heterogeneous population from demographic and symptomatic standpoint
Areas of advancement
• Genetics• Molecular/cellular signaling involved in epileptogenesis
– Age specific mechanisms– Shared neurobiology of ictal and nonictal components
• Imaging– Cellular– Clinical
• Quantitative neurophysiology– Spectral analysis, LTM, MEG
• AED development
HumanMouseBoth
SCN1ASCN2ASCN1BKCNA1KCNC2KCNQ1KCNQ2KCNQ3KCNMAKCNMB4CACNA1A CACNB4CACNG4 CACNA2D2ClCN2HCN2GABRA1GABRB3GABRG2CHRNA4CHRNB2 HTR2CGRIA2
SLC9A1SLC1A2SLC2A1KCC2ATP1A2NPY GAD2 ITPR1CAMK2APLCB1 SYN1+2SV2ABSNAP3D1 DCXDLX1OTXEMX2SOX1 FCN2UPARARX
NEUROD1GABBR1KCNJ6MECP2EPM2AFLN1CASPR2ALPLTRK1LAMR1P11RORAPTENCBP‐BAMT UBE3aCITCYSTBMYO5A TSC1, 2NHLRC1LGi1APP‐related
Ion channelsare thelargest subset
>100 Genes Linked to Monogenic Epilepsy
http://www.ncbi.nlm.nih.gov/books/NBK1318/Courtesy, Jeff Noebels, MD, PhD
HumanMouseBoth
SCN1ASCN2ASCN1BKCNA1KCNC2KCNQ1KCNQ2KCNQ3KCNMAKCNMB4CACNA1A CACNB4CACNG4 CACNA2D2ClCN2HCN2GABRA1GABRB3GABRG2CHRNA4CHRNB2 HTR2CGRIA2
SLC9A1SLC1A2SLC2A1KCC2ATP1A2NPY GAD2 ITPR1CAMK2APLCB1 SYN1+2SV2ABSNAP3D1 DCXDLX1OTXEMX2SOX1 FCN2UPARARX
NEUROD1GABBR1KCNJ6MECP2EPM2AFLN1CASPR2ALPLTRK1LAMR1P11RORAPTENCBP‐BAMT UBE3aCITCYSTBMYO5A TSC1, 2NHLRC1LGi1APP‐related
Ion channelsare thelargest subset
>100 Genes Linked to Monogenic Epilepsy
http://www.ncbi.nlm.nih.gov/books/NBK1318/Courtesy, Jeff Noebels, MD, PhD
Initial insult
Temporal Profile of Epileptogenesis
Emergence of spontaneous seizures
“Time Zero” EPILEPSY:
Cascade of events?
Therapeutic targets?
Biomarkers?
Rakhade, S. N. and Jensen, F. E. (2009),Nat. Rev. Neurol.
Worsening cognitive deficit?
Timing Target Therapeutic strategy Candidate agents
Immediate earlychanges
Post‐translationalphosphorylation
Kinase, phosphatase inhibitors, mTOR
KN‐62, FK506, rapamycin
Acetylation HDACs Valproate, SHA
AMPA receptors AMPAR antagonists Talampanel, topiramate, levetiracetam
NMDA receptors NMDAR antagonists Memantine, xenon, ifenprodil, Mg2+
GABA receptor GABAR agonists BZs, barbiturates
NKCC1 NKCC1 inhibitors Bumetanide
Subacutechanges
Inflammation Anti‐inflammatory compounds , microglialinactivators
ACTH, minocycline, doxycycline,
Neuronal death Block excitotoxicity, oxidative stress
Memantine, Epo
HCN1 channels ih‐blocker ZD7288
Cannabinoid receptors CB1‐R antagonists SR14176A, SR141716
Chronic changes Sprouting Block protein synthesis Rapamycin, cyclohexamide
Gliosis Anti‐inflammatory agents Cox2 inhibitor, minocyclineRakhade, S. N. and Jensen, F. E. (2009),Nat. Rev. Neurol.
Maturational changes in Glutamate and GABA receptor function in the developing brain
Rakhade, S. N. and Jensen, F. E. (2009),Nat. Rev. Neurol.Talos et al J. Comp Neurol, 2006; Dzhala V et.al. Nature Medicine, 2005
Maturational changes in Glutamate and GABA receptor function in the developing brain
Rakhade, S. N. and Jensen, F. E. (2009),Nat. Rev. Neurol.Talos et al J. Comp Neurol, 2006; Dzhala V et.al. Nature Medicine, 2005
Neo
natal Seizures
Infantile Spasm
s
Land
au
Kleffner
Benign
Rolandic
Maturational changes in Glutamate and GABA receptor function in the developing brain
Rakhade, S. N. and Jensen, F. E. (2009),Nat. Rev. Neurol.Talos et al J. Comp Neurol, 2006; Dzhala V et.al. Nature Medicine, 2005
AUTISM
Risk of epilepsy in children with autism
• Large cohort of children with autism
Modified from Table 1Tuchman et al. Pediatrics, 1991
Degree of MR N N (%) Epilepsy
Severe 77 30 (39%)
Moderate/Mild 145 8 (6%)
Nl intelligence 68 9 (13%)
Total 290 47 (16%)
cognitive deficitsautism
epilepsyepileptogenesis
Synaptic plasticitySynaptic receptorsSignaling molecules
neurotrophins
ALL SEIZURE INDUCED
Enhanced excitabilityin the developing brain
Interaction and convergence between brain development, epilepsy and autism? NT receptors
p‐AMPAp‐NMDAp‐GABA
Signalingkinasesphosphatasesmecp‐2mTOR, RhebreelinERKAKTCDKL5FMRPUbe3A
NeurotrophinsBDNF
Rett’sTSCLissencephaly
West’sFragile XAngelmans
autism
Synaptic “plasticity” and synaptic strengthening
Modified from Lamprecht and LeDoux, Nature Neurosci Rev, 2004
New faster synapses
MeCP2
reelin mTOR
CDKL5FMRP
Ube3a
Epilepsy and autism converge at the synapse
Modified from Lamprecht and LeDoux, Nature Neurosci Rev, 2004
Mecp2
reelin mTOR
CDKL5 FMRP
West’ssyndrome
Rett’ssyndrome
Lissencephaly
Fragile X syndrome
Tuberous Sclerosis
Ube3a
Angelman’ssyndrome
Shared molecular targets?
Bidirectional Relationship Between Epilepsy and Depression
Authors Type of StudyPsychiatric History Preceding the Onset of Epilepsy/Controls
Forsgren and Nystrom. 1990 Population-based 7 times the history of depression17 times in case of TLE
Hersdorffer et al. 2000Population-based
(Onset of epilepsy >age 55)
4 times the history of depression
Hersdorffer et al. 2006 Population-based(Iceland all ages)
5 times the history of suicidalityTwice the history of major depression
Courtesy Andres Kanner, MD
Neurotransmitters Involved inthe Pathogenesis of Depression and Epilepsy
• Epilepsy– Serotonin
– Norepinephrine
– Dopamine
– GABA
– Glutamate
– CRF
• Mood disorders– Serotonin
– Norepinephrine
– Dopamine
– GABA
– Glutamate
– CRF
Courtesy Anders Kanner, MD
Courtesy Gary Richerson, MD
Serotonin, Epilepsy & Depression
• Increased risk of suicide in epilepsy patients• Bi‐directional effects
Increased incidence of seizures in depressionIncreased incidence of depression in seizures Underlying 5‐HT defects in both?
• Many antidepressants (SSRIs & SNRIs) inhibit seizures• Many anticonvulsants are used in affective disorders• Vagal Nerve Stimulation (VNS) has effects on depression
• Ecstasy toxicity – May cause depression & seizures
Death rates in epilepsy patients
• Patients with epilepsy are 24 times more likely to die of sudden death than the general population– SUDEP is the leading cause of death in patients with uncontrolled epilepsy
• 12% risk of SUDEP in refractory epilepsy not on medication
• Mechanism(s) unknown: – Cardiac vs respiratory vs “electrocerebral shutdown”– Serotonin depleted by seizures, involved in central control of respiratory drive
– Channelopathies are common to heart and brainTomson et al, Lancet Neurology, 2008Silanpaa and Shinnar, NEJM 2010
Death rates in epilepsy patients
• Patients with epilepsy are 24 times more likely to die of sudden death than the general population– SUDEP is the leading cause of death in patients with uncontrolled epilepsy
• 12% risk of SUDEP in refractory epilepsy not on medication
• Mechanism(s) unknown: – Cardiac vs respiratory vs “electrocerebral shutdown”– Serotonin depleted by seizures, involved in central control of respiratory drive
– Channelopathies are common to heart and brainTomson et al, Lancet Neurology, 2008Silanpaa and Shinnar, NEJM 2010
Death rates in epilepsy patients
Clinical diagnostic advances
• Epilepsy centers can access the cutting edge of clinical diagnostics on an every day basis– Advanced neurophysiology
• Digitial EEG, Long term monitoring, Intracranial grids and strips (electrocorticography/ECoG)
• Quantitative computational analysis, high frequency oscillations• Magnetoencephalography
– Advanced anatomical imaging• MRI, DTI
– Advanced functional imaging• PET, SPECT, fMRI, connectomics
– Genetic screening• Genome, SNPs….• Pharmacogenomics
Technological advances and epilepsy
Worrel, et al 2004; Suedo, et al Epil Res 2010; Van der Heide,et al, Clin Neurophys, 2010; 2010; Hagmann, et al PloS Biol. 2010
Treatment Advances• 25 new drugs developed for clinical trials in the last 25 years, 11 now FDA
approved• Despite this, up to 40% of patients with epilepsy are not adequately
controlled on medication – And that is just the seizures
• Increased rate of surgical resection for focal lesional/nonlesional epilepsy– no survey covering adult and pediatrics since 1993 (Engel et al)– No change in number of years to referral
• Pediatric cases 5 years• Adult cases 20+ years
– Success rate from surgery approximately 30‐50% depending on age• New devices
– VNS– DBS– TMS
• No medical treatment in 2011 represents a CURE– Surgical treatment may cure but only applicable to a small % of the refractory
population– Comorbidities largely overlooked as a unique treatment target
Therapy development pipelinepast 25 years
ASP/NINDS
Pharma/IndustryAcademia+NIH/VA/DOD/FDA
NGOs
SOURCE CLINICAL TRIALS FDA approval
26 new drugs/4+ devicesFelbamateGabapentinVigabatrinLamotrigineTopiramateTiagabineOxcarbazepineLevetiracetamZonisamidePregabalinRufinamideLacosamideBrivaracetamDP‐VPAGanaxoloneCarisbamateSeletracetamStiripentolTalampanelValrocemideEslicarbazepineRetigabinePerampanelLosigamoneBumetanide
VNSDBS‐SANTE trial‐RNS trialTMS
FelbamateGabapentinVigabatrinLamotrigineTopiramateTiagabineOxcarbazepineLevetiracetamZonisamidePregabalinRufinamideLacosamideACTH
VNS
13 new drugs, 1 device
Advances that are making a difference• Molecular mechanisms or epileptogenesis
– Plasticity cascades• Ion channels and transporters, etc‐ new targets
– Immunology• Molecular mechanisms of comorbidities
– Depression– Autism– Alzheimer’s Dementia– SUDEP
• Clinical and genetic correlations (GWAS, sequencing)– Example SCN1A gene
• New technologies– Imaging in daily use
• PET, MEG, SPECT, DTI– Connectome– Quantitative analysis of digital EEG
• Algorithms for seizure prediction• High frequency oscillations – a potential biomarker
• New treatments– 26 new drugs, dietary regimens, improved surgical techniques, devices
Public Health Surveillance
• In 2011, how do we use existing clinical networks, ongoing studies to evaluate the burden of epilepsy• www.clinicaltrials.gov lists over 600 epilepsy related trials – is this a
source of selected data?
• How to utilize new tools provided by reformed health care system, comparative effectiveness, in the age of electronic medical records
• Cover previously understudied specific populations including pediatrics, elderly, women
• Definition of what constitutes active epilepsy (to include comorbidities) or epilepsy “in remission”– definition of cure (to ascertain more than simply seizure control) will be an issue
Population and Public Health Research• What are risk factors for refractory epilepsy?
– Accelerate path to care, diagnostics and pharmacogenomics– Enriched populations for research study
• What are risk factors for comorbidities, including SUDEP?– Accelerate path to referral, new diagnostics– Enriched populations for research study
• If seizures are treated, there is still a need for surveillance of burden of residual comorbidity
• Recognition that epilepsy is often “hidden” inside another primary diagnosis (eg. depression, dementia, autism)
• What is long term outcome after epilepsy surgery?– How do we define “cure”?
• Newly emerging populations with epilepsy– Survivors of prematurity, infant injury– New therapeutic choices during pregnancy– Growing population of elderly patients afflicted with epilepsy
Health Policy
• Access to care– Define guidelines as to what level of epilepsy meets criteria for
immediate referral to an epilepsy center– Define what constitutes treatment failure – Examine social, educational, and workplace support services for
patients with epilepsy– Early intervention not only of seizures, but of comorbid symptoms
• Payment of care– What path to referral to an epilepsy care center will be approved– How will nutritional treatments be covered (ketogenic diet)– What will policy be with respect to generic/brand name
pharmaceuticals– High level of diagnostic testing must be covered due to changing
nature of disease, and changing response to treatment within an individual
Education
• Patient and public– Broader definition of the spectrum of epilepsy to improve self‐identification
– Awareness of wide range of treatment options– Address and eliminate stigma
• Health care professionals– Improve education at all levels – Improve accuracy of diagnosis in primary care– Develop and then educate with guidelines for referrals to different levels of specialized care
January 10, 2011
The IOM report is necessary to enable patients and the professional community involved in care, education, and research to meet the challenges of this disease in the 21st century and work towards the eventual eradication of this common, disabling, and stigmatized condition