Download presentation
Presentation is loading. Please wait.
Published byKerry Goodman Modified over 9 years ago
1
Kristen K. Reynolds, PhD Associate Medical Director, VP Laboratory Operations Copyright 2010 PGXL Laboratories LLC, Louisville KY All materials herein are the exclusive property of PGXL Laboratories
2
Enabling Personalized Medicine Intuitive Medicine Precision Medicine
3
~60% of meds in top 20 list causing ADRs are linked to a genetic variation ~122 drugs have FDA box warnings related to genetics
4
Applications of pharmacogenomics Individualizing drug therapy selection Predicting adverse reactions, dosing, response Identify increased sensitivity to drug interactions
5
CYP2D6 DRD2 5-HTT 5-HTR2A SSRI SNRI TCA FGA SGA Metabolism Clearance PD Response PK UMs EMs PMs X Dependent on drug concentration, receptor expression and affinity CYP2D6 and psychotropic receptor variants alter drug dose and/or selection Ramey-Hartung, El-Mallakh, Reynolds. Clin Lab Med 2008;28:627-43.
6
Clinical Applications of Pharmacogenetic Information Anti-coagulation – Warfarin – Clopidogrel Psychiatry – Anti-depressants Oncology – Thiopurines – Tamoxifen – EGFRi’s Pain management – Codeine – Methadone Epilepsy – Phenytoin – Carbamazepine Diabetes – Glipizide
7
Application of Pharmacogenomics to warfarin therapy
8
The Problem Reynolds et al. Pers Med 2007;4(1):11-31.
10
40% of population have deficient CYP2C9 > 70% of population have decreased VKOR and are more sensitive to warfarin Genetics of Warfarin metabolism and response
11
Accumulation Steady-State Linder et al. J Thrombosis & Thrombolysis 2002;14:227-232 CYP2C9 status increases magnitude of accumulation/unit dose as well as time to achieve steady-state
12
VKORC1 -1639 G>A genotype dictates S-warfarin therapeutic concentration Dose 2.7 ± 1.2 mg Dose 4.2 ± 2.2 mg Dose 6.7 ± 3.3 mg All within INR 2-3 Zhu Y et al. Clin Chem 2007;53(7):1199-1205.
13
Calculation of estimated maintenance dose Modeling of individualized response to dose changes Guidance for: Monitoring strategy Dosing modifications Transition: induction to maintenance therapy PerMIT:Warfarin © Powered by PG XL Laboratories
14
All; 66 y/o, female, 130 lbs
16
No Loading Dose PerMIT-guided Loading Dose
17
Concentration/Response Time Profile Genotype: CYP2C9*1*2 // VKORC1 GG Estimated Maintenance dose: 6.3 mg/d (5.7 – 7.0) Time to Steady-State: 11 to 15 days Target therapeutic concentration: 0.8 mg/L...... 6 mg/d.......10, 10, 8, 6 mg/d Linder MW et al. 2011 (unpublished results) CONFIDENTIAL
18
Application of Pharmacogenomics to Anti-platelet therapy
19
CYP2C19 - Plavix Clopidogrel (Plavix) is a pro-drug which is converted to an active metabolite by CYP2C19 Active metabolite is what elicits the desired antiplatelet response ~ 30% of patients have deficiency in CYP2C19
20
Influence of CYP2C19 on Clopidogrel Response
21
New Draft Report CONFIDENTIAL COPYRIGHT PGXL LABORATORIES 2012 *Lack of efficacy due to failure to produce active metabolite; † Increased risk of adverse events due to diminished drug clearance. CYP2C19 Poor Metabolizer (PM): This patient’s genotype is consistent with significantly reduced CYP2C19 enzymatic activity. PMs are at increased risk of drug-induced side effects due to diminished drug elimination of active drugs. Patients with no CYP2C19 function (PMs) taking clopidogrel lack adequate antiplatelet response and remain at risk for cardiovascular events, including thrombosis, myocardial infarction, stroke, and death.
22
Application of Pharmacogenetics to Pain Management
23
CYP2D6 - Opioids Hydrocodone Oxycodone Methadone Others… Propoxyphene Tramadol Codeine
24
CODEINE CYP3A4 CYP2D6 Norcodeine Morphine Morphine-6-glucuronide Morphine- 3-glucuronide Active opioid effects Renal Excretion Reynolds KR et al. Clin Lab Med 2008;28:581–598. CYP2D6 PM: inadequate morphine CYP2D6 UM: morphine toxicity
25
Decreased drug metabolism = lack of efficacy – Poor pain control – Mis-interpretation of drug seeking behavior Ultra-rapid drug metabolism = possible side effects – Over-production of active compound – Mis-interpretation of over-compliance – Possible lower doses required Effects of CYP2D6
26
CYP2D6 Variants Extensive Metabolizers (EM) 55 – 60 % of population Intermediate Metabolizers (IM) 25 – 30% of population Poor Metabolizers (PM) 7 – 10 % of population Ultra-rapid Metabolizers (UM) 1 – 3 % of population
27
Application of Pharmacogenomics to behavioral health
28
28 CASE: Depression/ADHD 51 y/o male Problematic Polypharmacy (Atomoxetine, Topiramate, Oxcarbazapine, Aripaprazole,Valproic acid) Genotyping results
29
29 Relevance to case (drugs affected) Medication PGx GenePM Effect atomoxetineCYP2D6 Reduced clearance. Half life ~ 5 times longer aripiprazoleCYP2D6 80% increase in exposure, half-life twice as long
30
Adjust dosage based on PK Goal to achieve normalized exposure and ADR risk Adjust monitoring expectations for SS delay Allow for adequate “wash- out” period How to apply PGx to atomoxetine therapy?
31
UMIMPM CODEINE AMITRIPTYLINE CLOMIPRAMINE OXYCODONE RISPERIDONE ZUCLOPENTHIXO L PROPAFENONE RISPERIDONE VENLAFAXINE CODEINE AMITRYPTYLINE OXYCODONE RISPERIDONE TAMOXIFEN TRAMADOL VENLAFAXINE Medications to avoid by CYP2D6 phenotype
32
*Lack of efficacy due to failure to produce active metabolite; † Increased risk of adverse events due to diminished drug clearance. CYP2D6 Poor Metabolizer (PM): This patient’s genotype is consistent with a lack of CYP2D6 enzymatic activity. PMs are at increased risk of drug-induced side effects due to diminished drug elimination of active drugs or lack of therapeutic effect resulting from failure to generate the active form of the drug, as is the case with pro-drugs. New Draft Report CONFIDENTIAL COPYRIGHT PGXL LABORATORIES 2012
33
Fundamental Principles Genetic variability in drug metabolism significantly increases risk of ADRs and non-response Genetic variation can be managed : Poor Metabolizers Decreased maintenance dosing (20 – 70% ) Increased pro-drug dosing Allow longer time to reach Steady-State Allow longer time between medication changes Increased observation Choose alternative medication Rapid metabolizers Increased dosages (50 – 200%) Decreased pro-drug dosages
34
CYP2C9 CELECOXIBCELEBREX IBUPROFENADVIL, MOTRIN NAPROXENALEVE GLYBURIDEDIABETA GLIPIZIDEGLUCOTROL TOLBUTAMIDEORINASE GLIMEPIRIDE AMARYL PHENYTOINDILANTIN FLUVASTATINLESCOL LOSARTANCOZAAR CYP2C9/VKORC1 WARFARINCOUMADIN CYP2C19 CLOPIDOGRELPLAVIX CITALOPRAMCELEXA ESCITALOPRAMVARIOUS BRANDS IMIPRAMINETOFRANIL SERTRALINEZOLOFT OMEPRAZOLE PRILOSEC ESOMEPRAZOLENEXIUM PANTOPRAZOLEPROTONIX RABEPRAZOLEACIPHEX LANSOPRAZOLEPREVACID DIAZEPAMVALIUM NELFINAVIRVIRACEPT Medications and metabolic pathways
35
Medications and CYP2D6 pathway Pain Management Psychiatry CodeineVarious brandsAmitriptylineVarious brands OxycodoneOxycontin, variousClomipramineAnanfranil HydrocodoneVarious brandsDesipramineNorpramin DextromethorphanVarious brandsDoxepinSinequan TramadolUltram, variousImipramineTofranil NortriptylinePamelor, Aventyl Cardiology FluoxetineProzac CarvedilolCoregParoxetinePaxil MetoprololToprol-XLVenlafaxineEffexor PropanololInderal, variousRisperidoneRisperidol PropafenoneRythmolAripiprazoleAbilify FlecainideTambocorZuclopenthixolVarious brands MaprotolineLudiomil Other DuloxetineCymbalta LoratadineClaritin DonepezilAricept TamoxifenVarious brands
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.