the current state of pharmacogenomics
DESCRIPTION
A presentation covering how far we have come with pharmacogenomic and how far we have to go. Background about what pharmacogenomics is and why it should matter to you is provided. Additionally, current physician and pharmacy benefit manager practices are covered. A step wise process for how to integrate pharmacogenomics into your practice is included. And lastly, examples of pharmacists using pharmacogenomics in their practice is provided.TRANSCRIPT
The Current State of
Pharmacogenomics
Marti LarrivaPharmD Candidate, Class of 2014
University of Arizona
ObjectivesDiscuss background and relevance of pharmacogenomics
Describe current state of pharmacogenomics
Lay out a step-wise process for integrating pharmacogenomics into your clinical practice
Discuss examples of pharmacists performing pharmacogenomics
BackgroundPharmacogenomics
Relevance
PharmacogenomicsDefinition: The genetic influence of your response
to drugs
RelevanceFDA pharmacogenetic modifications to >100 drug labels
Of top 200 drugs2003 – 1.5%
2011 – 11%
Mayo-Medco Warfarin Effectiveness Study28-43% reduction in hospitalizations due to thromboembolism or bleeding
PREDICT-1 Study – Abacavir (NRTI)56% reduction in clinical hypersensitivity reactions
100% reduction in immunologically confirmed hypersensitivity reactions
Moaddeb J, Haga SB. Therapeutic Advances in Drug Safety. 2013.
Mallal S, Phillips E, Carosi G et al. N Engl J Med. 2008;358(6):568-79.Epstein RS, Moyer TP, Aubert RE et al. J Am Coll Cardiol.
2010;55(25):2804-12.
Current State of Pharmacogenomics
How often is it being used?
Belie
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Order
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Antici
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Test
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20.0%
40.0%
60.0%
80.0%
100.0%
97.6%
29.0%10.3% 12.9% 26.4%
57.0%
Medco/AMA Nationwide Physician Survey Key Findings
Perc
en
tag
e o
f R
esp
on
den
ts
Stanek EJ, Sanders CL, Taber KA et al. Clin Pharmacol Ther. 2012;91(3):450-8.
CPIC & ASCPT 2009/2010 Survey
Challenges:Interpretation of genetic results
Translating results into clinical actions
Provider resistance
Cost of testing and reimbursement
CPIC = Clinical Pharmacogenetics Implementation ConsortiumASCPT = American Society for Clinical Pharmacology and Therapeutics
Relling MV, Klein TE. Clin Pharmacol Ther. 2011;89(3):464-7.
PBM Facilitated Pharmacogenomic
TestingPBMs = Pharmacy Benefits Managers =
process prescriptions for groups that pay for drugs
(insurance companies or corporations)
Express Scripts
Express Scripts. Services: Personalized Medicine. Available at: http://www.express-scripts.com/services/physicians/personalizedmedicine/
Use Class Drug Gene Concern
HIV CCR5 receptor antagonist
Maraviroc CCR5 tropism
Efficacy
Nucleoside reverse transcriptase inhibitor
Abacavir HLA-B*5701
Toxicity
Cancer Protein kinase inhibitor
ImatinibNilotinibDasatinib
BCR/ABL Efficacy
Cardiac Vitamin K antagonist
Warfarin CYP2C9VKORC1
Toxicity
Antiplatelet Clopidogrel CYP2C19 Efficacy
CVS CaremarkUse Class Drug Gene Concer
n
HIV Antiretrovirals Abacavir HLA-B*5701
Toxicity
Cancer Thiopurines AzathioprineThioguanine
TPMT Efficacy
Anti-estrogens Tamoxifen CYP2D6 Efficacy
Protein kinase inhibitor
ImatinibNilotinibDasatinibErlotinibLapatinib
BCR/ABL Efficacy
Cardiac Antiplatelets Clopidogrel CYP2C19 Efficacy
Seizure Antiepileptics Carbamazepine HLA-B*1502
Toxicity
Hepatitis C
Antivirals Peginterferon alpha 2aRibavirin
IFNL3HLA-B*44
EfficacySandburg J, Christal N, Marrazo J. Press Release - CVS Caremark; 2010. Available from: http://investor.cvs.com/phoenix.zhtml?c=99533&p=irol-newsArticle&id=1433463.
Integrating pharmacogenomics into your practice
A step by step process
Patient CaseMr. Angina is a 63 y/o Caucasian male with a PMH of DM2, HTN, and HLD. He was recently diagnosed with a STEMI and underwent stent placement. Among several other medications, he was started on Clopidogrel.
His PCP, Dr. Idunno, receives a phone call from ES about Clopidogrel pharmacogenomic testing.
He doesn’t trust ES and hasn’t heard of this test before.
He comes to you for help:
Should he order this test?
What should he do with the results?
Step 1Check your pharmacogenomic resources to if there are genes related to the drug
CPIC Reviewed Drugs
Clinical Pharmacogenetics Implementation Consortium (pharmgkb.org)
Guidelines for HOW genetic tests should be used based upon peer reviewed evidence
NOT focused on WHETHER to order the test.
Assumption ->Preemptive genetic testing
Published Guidelines Upcoming Publications
Thiopurines Carbamazepine
Clopidogrel Capecitabine
Warfarin Phenytoin
Codeine Rasburicase/Septra
Abacavir Pegintron
Simvastatin SSRIs
Allopurinol Ivacaftor
TCA’s Irinotecan
Scott SA, Sangkuhl K, Gardner EE et al. Clin Pharmacol Ther. 2011;90(2):328-32.
Recommended Therapeutic use of Clopidogrel based on
CYP2C19 genotypeLikely Phenotype
Genotype Implications for Clopidogrel
Therapeutic Recommendations
Classification of recommendations
Ultrarapid Metabolizer(5-30%)
CYP2C19: *1/*17CYP2C19: *17/*17
Increased platelet inhibition
Standard Clopidogrel dosing
Strong
Extensive Metabolizer(35-50%)
CYP2C19: *1/*1
Normal platelet inhibition
Standard Clopidogrel dosing
Strong
Intermediate Metabolizer (18-45%)
CYP2C19: *1/*2CYP2C19: *1/*3CYP2C19: *2/*17
Reduced platelet inhibition = increased risk of CV events
Alternative antiplatelet: Prasugrel or Ticagrelor*
Moderate
Poor Metabolizer(2-15%)
CYP2C19: *2/*2CYP2C19: *2/*3
Significantly reduced platelet inhibition = increased risk of CV events
Alternative antiplatelet:Prasugrel or Ticagrelor*
Strong* only if no contraindications to these alternatives
Scott SA, Sangkuhl K, Gardner EE et al. Clin Pharmacol Ther. 2011;90(2):328-32.
Step 2Evaluate the pharmacogenomic test
General Considerations1. Gene Association
Positive Predictive Value (PPV) – percentage of patients who test positive for the allele and will be affected
Negative Predictive Value – percentage of patients who test negative for the allele and will NOT be affected
2. Frequency
Occurrence of variant gene in general population
Often categorized by race/ethnicity
3. Clinical Utility
What evidence exists to show that doing this test will improve patient outcomes?
Clopidogrel Patient Case
1. Gene Association – CYP2C19*2 carrier status
PPV = % of patients with CYP2C19*2 who will have residual platelet aggregation (RPA) on clopidogrel
PPV = 41.3%
22.4 % of patients with fully functional enzyme have RPA
NPV = % of patients without CYP2C19*2 who will NOT have residual platelet aggregation
NPV = 77.6%
2. Frequency
12% of Americans, 15% of Africans, and 29% of East Asians carry the CYP2C19*2 allele
Ned Mmsc Phd RM. PLoS Curr. 2010;2:10.1371/currents.RRN1180.
Scott SA, Sangkuhl K, Gardner EE et al. Clin Pharmacol Ther. 2011;90(2):328-32.
3. Clinical Utility
No published RCT evaluating CYP2C19*2 testing utility
Mayo Clinic TAILOR-PCI study – Enrolling patients to evaluate “bedside” CYP2C19*2 testing post PCI and impact on major adverse CV events
Meta-analyses of Clopidogrel treated ACS patients undergoing PCI:
Homozygous for CYP2C19*2 have an increased risk of adverse CV events (HR 1.76; 95% CI 1.24-2.50) and stent thrombosis (HR 3.97; 95% CI 1.75-9.02) compared to CYP2C19 full function homozygotes
Clopidogrel Patient Case
Scott SA, Sangkuhl K, Gardner EE et al. Clin Pharmacol Ther. 2011;90(2):328-32.
Roberts J, Wells G, May M, et. al. Lancet. 2012;379:1705-11.
Pereira, N. TAILOR-PCI. Available from: http://www.clinicaltrials.gov/ct2/show/NCT01742117
Step 3Make your clinical decision
Clinical DecisionFor Mr. Angina, if ES is offering to coordinate test and is covered by insurance provider, do the test!
Generally, consider performing the test in patients who have had an event while on Clopidogrel
If preemptive testing were available, that would be ideal given events generally occur soon after PCI placement
Scott SA, Sangkuhl K, Gardner EE et al. Clin Pharmacol Ther. 2011;90(2):328-32.
Pharmacists in Pharmacogenomics
Filling in the gapOpportunity to lead
St. Jude Pharmacist-Managed
Pharmacogenetic ServicesIncorporated PGx services into PK services
Gene Affected Formulary Drugs
Effect of variant allele
Thiopurine Methyltransferase (TPMT)
6-mercaptopurineThioguanineAzathioprine
Severe, sometimes fatal, hematological toxicity
Cytochrome P450 2D6(CYP2D6)
Codeine Poor metabolizers = no analgesic effect Ultrarapid metabolizers = high toxicity risk
Uridine glucouronosyltransferase 1A1 (UGT1A1)
Irinotecan Increase potential for hematologic or GI toxicity
Crews KR, Cross SJ, McCormick JN et al. Am J Health Syst Pharm. 2011;68(2):143-50
Patient EMR
Crews KR, Cross SJ, McCormick JN et al. Am J Health Syst Pharm. 2011;68(2):143-50
St. JudePG4KDS ProgramTo test or not to test?
Preemptively screen for 225 genes known to effect drug metabolism and place that information into the EMR
Codeine (CYP2D6) and Azathioprine (TPMT)
Pharmacists involved in continued evaluation of new research
Erikson A. Pharmacy Today. American Pharmacists Association; 2013. Available from: http://www.pharmacist.com/pharmacogenetics-key-personalized-therapeutic-decisions
Take HomePharmacogenomic testing can be useful
Physicians are NOT using it because they lack knowledge
Pharmacists need to become informed advocates
References1. Crews KR, Cross SJ, McCormick JN et al. Development and implementation of a pharmacist-managed clinical pharmacogenetics service. Am J Health Syst Pharm. 2011;68(2):143-50.
2. Epstein RS, Moyer TP, Aubert RE et al. Warfarin genotyping reduces hospitalization rates results from the MM-WES (medco-mayo warfarin effectiveness study). J Am Coll Cardiol. 2010;55(25):2804-12.
3. Erikson A. Pharmacogenetics: The key to personalized therapeutic decisions. Washington, DC: American Pharmacists Association; 2013. Available from: http://www.pharmacist.com/pharmacogenetics-key-personalized-therapeutic-decisions. (Accessed 6/1/2013).
4. Express Scripts. Services: Personalized Medicine. Available at: http://www.express-scripts.com/services/physicians/personalizedmedicine/. Accessed 6/1, 2013.
5. Mallal S, Phillips E, Carosi G et al. HLA-B*5701 screening for hypersensitivity to abacavir. N Engl J Med. 2008;358(6):568-79.
6. Moaddeb J, Haga SB. Pharmacogenetic testing: Current evidence of clinical utility. Therapeutic Advances in Drug Safety. 2013.
7. Ned Mmsc Phd RM. Genetic testing for CYP450 polymorphisms to predict response to clopidogrel: Current evidence and test availability. application: Pharmacogenomics. PLoS Curr. 2010;2:10.1371/currents.RRN1180.
References cont’d.
8. Pereira, N. Tailored Antiplatelet Therapy Following PCI (TAILOR-PCI). ClinicalTrials.gov [Internet]. Bethesda (MD): National Library of Medicine (US) -2013. Available from: http://www.clinicaltrials.gov/ct2/show/NCT01742117
9. Relling MV, Klein TE. CPIC: Clinical pharmacogenetics implementation consortium of the pharmacogenomics research network. Clin Pharmacol Ther. 2011;89(3):464-7.
10. Roberts J, Wells G, May M, et. al. Point-of-care genetic testing for personalisation of antiplatelet treatment (RAPID GENE): a prospective, randomised, proof-of-concept trial. Lancet. 2012;379:1705-11.
11. Sandburg J, Christal N, Marrazo J. CVS caremark and generation health outline target medications that will be the focus of new pharmacogenomics partnership. Press Release. Online: CVS Caremark; 2010. Available from: http://investor.cvs.com/phoenix.zhtml?c=99533&p=irol-newsArticle&id=1433463. (Accessed 6/1/2013).
12. Scott SA, Sangkuhl K, Gardner EE et al. Clinical pharmacogenetics implementation consortium guidelines for cytochrome P450-2C19 (CYP2C19) genotype and clopidogrel therapy. Clin Pharmacol Ther. 2011;90(2):328-32.
13. Simon T, Verstuyft C, Mary-Krause M et al. Genetic determinants of response to clopidogrel and cardiovascular events. N Engl J Med. 2009;360(4):363-75.
14. Stanek EJ, Sanders CL, Taber KA et al. Adoption of pharmacogenomic testing by US physicians: Results of a nationwide survey. Clin Pharmacol Ther. 2012;91(3):450-8.
Questions?