Presentation on theme: "Ethics in Alzheimer's Disease: New diagnostic criteria, new biomarkers, new challenges Steven T. DeKosky, MD James Carroll Flippin Professor of Medical."— Presentation transcript:
Ethics in Alzheimer's Disease: New diagnostic criteria, new biomarkers, new challenges Steven T. DeKosky, MD James Carroll Flippin Professor of Medical Science Vice President and Dean University of Virginia School of Medicine Charlottesville, VA USA National Press Foundation Washington, DC December 7, 2010
Disclosures Consultant/Advisory Boards : Bristol Myers Squibb, Eisai, Lilly, Merck, Novartis, Pfizer, PsychoGenics Off-Label Discussion: –None Special acknowledgements : Stephen Post, Stony Brook University Robert Green, Boston University
Categories of Ethics Questions in AD (and other late life dementias) Moral, cultural and socio-political issues Respect and autonomy –balance of responsibility to individual vs. society, e.g., driving privileges End of Life Care –Comfort, feeding, withholding nutrition or water Diagnosis and Truthtelling The Role of Biomarkers –Confirmation of Diagnosis, Earlier Diagnosis, Risk Assessment in Normals
Increasing Global Burden of AD: Cultures differ in their dealing with dementia
Moral, Cultural, and Socio-Political Issues Affirmation of and respect for people with AD and other disorders involving loss of self (e.g., “deeply forgetful”) –Example, South Korea efforts to honor people with dementia –Justice and protection Whose responsibility are the Deeply Forgetful? Family? Society? Government? –South Korea’s view… all of them Respite for family caregivers –Increased morbidity and mortality Ethicists: Cultivate a ‘culture of acceptance’ –The glass is half full (celebrate what is still available to others, not continue to mourn for what is lost)
Biomarkers Diagnostic Confirmation Increased Accuracy in MCI Risk Assessment in Asymptomatic People What are they? How should they be used? Research or general availability?
DeKosky ST, Marek K. Science. 2003;302:830-834. Model for the progression of loss of neuronal function in neurodegenerative disorders. There is a prolonged period during which loss of neuronal function has occurred but symptoms have not yet appeared. Time Neuronal Function PreclinicalSymptomatic Diagnosis Clinical Ratings Natural History of Neurodegenerative Disorders
Linking Clinical Symptoms With Degree of Pathology Disease Progression No Disease No Symptoms Early Brain ChangesNoSymptoms AD Brain ChangesMildSymptomsMild, Moderate, or SevereImpairment NormalAD Pre- symptomatic AD Mild Cognitive Impairment ClinicalState BrainPathologicState SecondaryPrevention/ Early Tx TreatmentPrimaryPrevention Intervention
APOE and Alzheimer’s Disease normal population: in AD: normal population: in AD: E2 7%7% E379%40-50% E414%40-50% ALLELE FREQUENCY: Potential mechanisms: Impaired removal of beta amyloid Diminished neural regeneration Allele frequency twice as high in Africans & African Americans as in Caucasians
Genetic Biomarkers APOE is the major risk gene in AD REVEAL study, now 10 years on, has tracked individuals views and reactions to have genetic status “revealed.” Results benign thus far No other genes of near-equal power are likely to be discovered
REVEAL Conclusions Disclosure of APOE does not seem harmful –may actually reduce anxiety for some who find they are e4- Persons alter their LTC insurance purchasing learning their APOE genotype –If widespread would have insurance industry implications APOE4+ carriers –more likely to make changes (vitamins, exercise) even knowing such changes are not proven – Also more likely to purchase unregulated neutraceuticals The impact is less than expected –people come into the study with a baseline perception of their own risk –seem to have a psychological inertia
Structural and Biochemical Biomarkers Biochemical: CSF Beta amyloid, tau, phosph-tau –Diagnostic as well as predictive value Neuroimaging: MRI, FDG-PET, amyloid imaging –Used for diagnostic confirmation in a symptomatic person, for earlier definitive diagnosis in mild or uncertain symptoms (e.g., MCI), and for detection of AD pathology in asymptomatic individuals.
Evolution of Neuroimaging in AD Computed Tomography MRI Volumetric MRI Co-registration of MRI Functional MRI FDG Glucose PET Amyloid Imaging www.loni.ucla.edu/~thompson/AD_4D/dynamic.html. Helmuth L. Science. 2002;297:1260-1262. 39
Ethics Issues With Biomarkers Diagnostic information We can ascertain with high probability whether AD pathology is present in the brain How much to tell research participants about unvalidated research results?
CSF Aβ42 Amyloid imaging FDG-PET MRI hipp CSF tau Cog Fxn Best markers across a broad range are MRI and FDG-PET
Biomarkers for Earlier Diagnosis Lancet Neurol 2007; 6: 734–46 “They stipulate that there must also be at least one or more abnormal biomarkers among structural neuroimaging with MRI, molecular neuroimaging with PET, and cerebrospinal fluid analysis of amyloid β or tau proteins. “
CSF in Alzheimer’s Disease: Low Aβ and High Tau AβAβTau Concentration (pg/mL) Sunderland T, et al. JAMA. 2003;289:2094-2103.
CSF in MCI has elevated tau, decreased β- amyloid A combination of CSF T-tau and A42 at baseline yielded a sensitivity of 95% and a specificity of 83% for detection of incipient AD inpatients with MCI. The relative risk of progression to AD substantially increased in patients with MCI who had pathological concentrations of T-tau and A42 at baseline (hazard ratio 17·7, p0·0001). The association between pathological CSF and progression to Alzheimer’s disease was much stronger than, and independent of, established risk factors including age, sex, education, APOE genotype, and plasma homocysteine. Hansson et al.,2006
Imaging Amyloid in vivo in Humans Amyloid Cascade Hypothesis: –Amyloid deposition begins years before clinical symptoms Ability to image brain amyloid will impact: –Diagnosis (sensitivity and specificity TBD) –Prognosis (different patterns of progression?) –Monitoring anti-amyloid therapeutic interventions –Efficiency of drug development Current ligands, more in development: –PiB, AV-45, BF227, FDDNP. Bay compound PiB: Now in use in over 40 centers around the world F18-PiB in development at both GE and Pittsburgh –Just as accurate as C11-PiB
Mean Cortical PIB Binding in Nondemented Controls and AD (N=41) scBP -0.200 0.000 0.200 0.400 0.600 0.800 1.000 1.200202223494951565758585959596060606161626464667172727475757576777777798081838384858686727373797981848586 Mintun et al, 2006, Neurology Subject AGE ADControls
2 yrs Longitudinal Change in PiB Retention in a Questionably Positive Control over Two Years
PiB Binding (amyloid plaque density) in Cognitively Normal Elderly and AD Aizenstein et al., Arch. Neurol. 2008; 65: 1509-1517
Heterogeneity of Amyloid Binding in Asymptomatic Normal Elderly Courtesy of Reisa Sperling, Harvard Univ.
How will disease-modifying medications affect the field? Immediate pressure to identify subjects as early as possible Amyloid scans beginning at age 50, repeated every 5 years, as for colon cancer Public Health Message: “At 50, get evaluated head to tail! Have your colonoscopy and your PiB Scan.”
Operational Research Criteria for Preclinical AD Not intended as clinical diagnostic criteria Prognostic utility of these biomarkers in individual subjects remains unclear Not all individuals with neuroimaging evidence of AD changes will develop clinical symptoms during life –30% of non-demented 80+ year olds have evidence of AD in the brain at autopsy