Presentation on theme: "Taking Research and Development to the Clinic: Issues for Physicians AAAS/FDLI Colloquium I Diagnostics and Diagnoses Paths to Personalized Medicine Howard."— Presentation transcript:
Taking Research and Development to the Clinic: Issues for Physicians AAAS/FDLI Colloquium I Diagnostics and Diagnoses Paths to Personalized Medicine Howard Levy, MD, PhD Johns Hopkins University June 1, 2009
What is Personalized Medicine? Biomarkers and genetic tests Customization of medical care to the individual patient All aspects of carenot just biomarkers, not just genetics
Challenges & Opportunities Self-evident truths: Physicians want to help patients Time & resources are scarce Can biomarkers improve both?
Using a Biomarker Select a test Order a test Get it paid for Get it done Receive result Understand result Archive result Access result (now & future) Apply result in clinical care
Clinical Utility Does the biomarker improve clinical care? Pharmacogenetics Predictive testing Faster or more precise diagnostics
Clinical Utility What are the costs? Financial Time/Resources Social/Ethical/Legal Medical (incorrect conclusions) Psychological
Pharmacogenetics The right drug At the right time In the right dose Efficacy Adverse events
Warfarin Dosing Fixed-dose Clinical algorithm (weight, age, sex) This is personalized medicine! Pharmacogenetic (VKORC1 & CYP2C9) PGx explains ~40% of dose variability Clinical + PGx explains ~54% of variability
Intl Warfarin PGx Consortium N Engl J Med 360(8):753-764 February 19, 2009
Warfarin PGx Clinical Utility Likely to achieve therapeutic dose faster Relatively easy to order & receive results Often covered by 3 rd parties Algorithm freely available Improved efficacy & fewer adverse events? Seems likely Still being studied
Warfarin PGx Clinical Utility Limitations: Needs to be done promptly at initiation of therapy ~45% of dose variability unexplained Environmental factors remain important
Drug Metabolism: CYP450 >50% of all drugs Prodrug Active Drug Active Inactive Relevant Factors: Other drugs Diet & environment Genetic variants
CYP450 PGx Clinical Utility Genetic testing is available Is PGx testing better than trial & error? Drug choice & dosing recommendations? What if there are no alternatives? Psychological distress Relative risk Genetic determinism
Genetic Determinism Belief that clinical outcomes are inexorably defined by genetic factors Ignores: Genetic/epigenetic modifiers Environmental modifiers Variable expression Reduced penetrance
Predictive Testing Its tough to make predictions, especially about the future -Dan Quayle, Casey Stengel, et al. The future aint what it used to be -Yogi Berra
Genetic Risk Assessment Family History Varies over time DNA variants Stable over time Relative risk
GWAS: Genome-Wide Association Studies Really BIG case-control study 1000s of subjects 500,000 to 1,000,000 SNPs Power to detect small effect sizes Subject to same errors & biases as any other epidemiologic study
CAD Risk Assessment: Gene Environment Smoking, HTN, DM, etc: OR 10-20 SNPs: OR 1.2-2.0 (usually 1.2-1.3) Family History: intermediate
Heritability Proportion of disease predisposition that is due to inherited factors SNPssmall amount Other heritable factors (DNA & Non-DNA variants) Current tests assess only a small portion of heritability
Analytical & Clinical Validity Is the test accurate? Does the biomarker correlate clinically (retrospective vs. prospective study)? How are results of multiple tests combined? Validity is often assumed when test is offered clinically.
The Fallacy of Genetic Determinism Positive tests Disease Negative tests Health
Clinical Utility of Genetic Testing for Common Disease? What do the results mean? Small effect size Environmental factors Fallacy of genetic determinism Undue anxiety/false reassurance?
Clinical Utility of Genetic Testing for Common Disease? Modify therapy to reduce risk? Motivation to change behavior? Smoking, exercise & diet campaigns Does the Personalized Medicine model work?
Clinical Utility of Genetic Testing for Common Disease? Cost Large amounts of clinical data Paucity of tools to integrate data Uncertain plan of action May be appropriate for some patients
PM Opportunities Improved diagnostics Improved therapeutics Improved health maintenance More efficient use of time Lower health care costs Patient & physician satisfaction
PM Challenges Clinician Education Test indications Test validity Result interpretation Clinical utility Integration into clinical care
Clinician Education Learning Preferences Clinically relevant Just in time (point of care) Fast (<2 minutes) Increasingly Internet-based 2 o sources ( authority vs. accuracy) GeneFacts
PM Challenges Test Validity Transparency Providers lack time & knowledge to evaluate Regulation Slows progress, limits access, cost Paternalism vs. Autonomy
PM Challenges Test Ordering & Payment Facilitating ordering the correct test DTC testing vs. physician gatekeeper 3 rd party payers Paternalism vs. Autonomy
PM Challenges Receiving, Archiving and Accessing Results EHRs Can also prompt provider to order/use tests PHRs Information sharing between providers Does the data already exist? Privacy & Security
PM Challenges Clinical Utility Better assessment of health factors Genetic Environmental Better tools to combine environment, family history & biomarkers Studies of actual clinical outcomes (Hype Hope Reality)
The Art of Medicine Evidence-based medicine Based on population studies Individual people Autonomous Variably reliable Ever-changing environment Personalized Medicine Requires knowing & monitoring the patient and therapy at the individual level