Pharmacogenetics: 7 questions about highly effective implementation

Prof. dr. Henk-Jan Guchelaar

Clinical Pharmacy & Toxicology

Leiden University Medical Center

Leiden Academic Center for Drug Research

Spanish Society of Hospital Pharmacy meeting

Madrid, 31 January 2013

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Disclosures (January 2013)

• Institutional

• Patent EP 06119819.8 and US 60/840,973 (MTX efficacy)

• Tamoxifen prospective study (CYPTAM) (Roche, Amplichip®)

• Personal

• None declared

Leiden University Medical Center

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Translational Drug Research

Leiden University Medical Center Leiden Academic Center

for Drug Research

Two patients at your outpatient clinic

• Two patients A and B

• The same symptoms

• The same doctor

• The same diagnostic procedures

• The same diagnosis X

• The same treatment

• Drug Rx at a dose x mg/day

• After 3 weeks

• Patient A: symptoms resolved

• Patient B: still symptoms, side effects

• How is this possible?

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Pharmacogenetics: drug response is a heritable trait

7 Questions

•Q1: Do we need biomarkers to predict

drug response?

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8

‘Most drugs don’t work’

Effective (%)…..

• Alzheimer 30

• Depression (SSRI) 62

• Asthma 60

• Diabetes mellitus 57

• Incontinence 40

• Migraine (acute) 52

• Migraine (profyl.) 50

• Cradiac dysrhythmia 60

• Tumors 25

• Schizophrenia 60

• Reumatoid arthritis 50

• Reumat. art. (Cox-2) 80

• Hepatitis C 47 Spear, Trends Mol Med 2001;7(5):201

Clinical Drug Toxicity

• Harvard Medical Practice Study – Lucian Leape

• Nature of adverse events in hospitalized patients

• 30,195 randomly selected patients records

• 1,113 (= 3.7%) disabling injury caused by medical treatment

• 19% adverse drug events (ADEs)

• Hospital Admissions Related to Medication

• Incidence of hospital admissions related to drug related problems

• 21 hospitals in The Netherlands

• 5.6% of acute admissions were drug related: 50% preventable

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Prescribing drugs – Trial and Error

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Dx Guideline

Rx Clinical studies

•Dx

•Inclusion criteria

•Age

•Organ function

•Severity of disease

First choice Drug

•‘Normal’ dose

•Individualize

•Co-morbidity

•Co-medication

•Age, Organ function

Monitor effect

•Efficacy & Toxicity

•Tumorsize, Biomarkers

•Pain(score), Bloodpressure

•Cholesterol levels

•Liverfunction, Myalgia

Drug dose

•Increase/decrease

Switch drug

•Second choice Drug

11 11

Individualization of drug therapy

100% dose

DRUG A

50% dose

DRUG A

DRUG B

DNA Test

• High Blood Pressure

• Antihypertensive drug: 2-4 wks

BP cardiovascular risk

• Consequences of delay of efficacious

treatment

• 3 months

• 10 yr (= 120 mo) treatment may

result in an absolute risk reduction

of 2,5% of 10 years risk death

• absolute risk: 7,50% 7.56%

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Monitoring drug effects – ‘Trial and Error’ prescribing

• Metastatic colorectal cancer

• 3-6 courses chemotherapy: 9-18

weeks CT-scan response

• Consequences of delay of

efficacious treatment

• 2-4 months

• mCRC: OS= 24 months

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Monitoring drug effects – ‘Trial and Error’ prescribing

Biomarkers needed for predicting drug response

• Drug effect presents after

months-years

• Important clinical

consequences of treatment

delay

• Diseases with a poor

prognosis

• Severe side effects

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7 Questions

•Q2: Which are the sources of heritable

variability in drug response?

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Sources of variability in drug response

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Compliance

Absorption

Metabolism

Elimination

Target/Receptor

Signal transduction

Concentration-effect relationship

Toxicity

Inefficacy

CONC

TIME

Poor metabolizer

Ultrarapid metabolizer

Genetic variants encoding drug receptor

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receptor-agonist

Sunitinib toxicity – Pharmacogenetic biomarkers

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• 219 patients treated with sunitinib from five

Dutch medical centers

• mRCC (159), GIST (50), other (10)

• Toxicity was evaluated in first treatment cycle

(6 weeks) by NCI–CTC-AE version 3.0

• Aim was to identify genetic markers in the PK

and PD pathway of sunitinib that predispose for

toxicity

• 31 single nucleotide polymorphisms in 12

candidate genes – PK and PD sunitinib

Van Erp, J Clin Oncol 2009:27(26):4406-12

Sunitinib toxicity – Pharmacogenetic biomarkers

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RET

1580T/C

-1171C/G

-735G/A

-573G/T

738T/C 2251G/A -604T/C

-92G/A

54T/C

1191C/T

1718T/A

1501A/G

Pharmacodynamics

Van Erp, J Clin Oncol 2009:27(26):4406-12

1501A/G

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Sunitinib Metabolites

SU12662 (active) and inactive metabolites

ABCB1 (Pgp) (3435C/T, 1236C/T, 2677G/T)

ABCG2 (BCRP) (421C/A, 34G/A, -15622C/T, 1143C/T)

CYP3A4 (

CYP3A5 (6986A/G)

CYP1A1 (2455A/G)

CYP1A2 (-163A/C)

NR1I2 (-25385C/T, -24113G/A,

7635A/G, 8055C/T, 10620C/T, 10799G/A )

NR1I3 (5719C/T, 7738A/C, 7837T/G)

Pharmacokinetics

Van Erp, J Clin Oncol 2009:27(26):4406-12

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• Leukopenia

• CYP1A1 2455A/G OR= 6.24

• FLT3 738T/C OR= 2.8

• NR1I3 haplotype OR= 1.74

• Any toxicity > grade 2

• VEGFR2 1191C/T OR= 2.39

• ABCG2 haplotype OR= 2.63

• Mucositis

• CYP1A1 2455A/G OR= 4.03

• Handfoot syndrome

• ABCB1 haplotype OR= 2.56

Van Erp, J Clin Oncol 2009:27(26):4406-12

Sunitinib toxicity – Pharmacogenetic biomarkers

Sunitinib efficacy - Pharmacogenetic biomarkers

• Identify predictive biomarkers for

sunitinib efficacy in mRCC

• 136 mRCC ‘clear cell’

• PFS/OS

• 31 ‘single nucleotide

polymorphisms’ in 12 candidate

genes – PK en PD sunitinib

• Clinical characteristics

24 Van der Veldt, Clin Cancer Res 2011;17(3):620-9

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PFS OS

Favorable profile: (n=95) at least an A-allele in CYP3A5, a TCG copy in the

ABCB1 haplotype or a missing CAT copy in the NR1I3 haplotype

Median PFS: 13.1 mo vs 7.5 mo (p= 0.001)

Median OS: 19.9 mo vs 12.3 mo (p= 0.009)

Sunitinib efficacy - Pharmacogenetic biomarkers

Van der Veldt, Clin Cancer Res 2011;17(3):620-9

7 Questions

•Q3: How much variance is explained by

pharmacogenetics?

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How much variance is explained by pharmacogenetics?

Tamoxifen – CYP2D6

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O

N

H

CH3

CH3

OH

O

N

H

CH3

CH3

O

N

CH3

CH3

CH3

O

N

CH3

CH3

CH3

OH

TAMOXIFEN 4-OH-TAM

NDM-TAM ENDOXIFEN

CYP2D6

CYP2B6

CYP2C9

CYP2C19

CYP3A

CYP2D6

CYP3A4/5

CYP1A2

CYP2C9

CYP2C19

CYP2D6

Tamoxifen metabolism

CYP3A4/5

SULT1A1

UGT

SULT1A1

UGT

Dezentje, Clin Cancer Res 2009;15(1):15-21

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Genotype to phenotype translation

Roche, AmpliChip CYP450 Test, manual

E

Goetz, 2005

Presentation SABCS ‘09

CYP2D6 genotype association studies

Positive studies

N HR p

Goetz ’05 190 1.86 .08

Schroth ’07 197 1.89 .02

Newman ’08 68 3.6 .09

Ramon ’09 91 >1 .02

Bijl ’09 85 2.1 .03

Kiyotani ’08/’10 282 9.5 <.001

Xu ’08 152 4.7 .04

Lim ’07 21 .02

Bonanni ’06/’10 182 .04

Schroth ’09 1325 1.29 .02

Negative studies

N HR p

Wegman ’05 76 <1 NS

Wegman ’07 677 <1 .055

Nowell ’05 162 .67 .19

Okishiro ’09 173 .6 .39

Toyamo ’09 154 NS

Dieudonnée ’09

Dezentje’10 747 1 NS

Goetz 2,880 NS

Dezentje, ASCO 2010

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CYP2D6 genotype – endoxifen concentration

Jin, J Natl Cancer Inst ; 2005:30

wt/wt = no *3, *4, *5 or *6

wt/vt = one *3, *4, *5 of *6 allel

vt/vt = *4/*4

• 13C dextrometorphan breath test

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CYP2D6 phenotype – endoxifen concentration

Opdam, Cancer Chemother Pharmacol. 2012 Dec 11

Explained variance

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Drug (Genetic) variant R2 Variable

Warfarin VKORC1 25% dose requirement

+BSA 34%

+CYP2C9*3 40%

+Age 45%

+CYP2C9*2 50%

Acenocounarol CYP2C9 4.9% dose requirement

VKORC1 21.4% dose requirement

Irinotecan UGT1A1 *28 24% neutropenia

Methotrexaat sex + Rf status + smoking 35% DAS response

+DAS at baseline +

AMPD1 + ATIC + ITPA

+ MTHFD1

7 Questions

•Q4: How much evidence is needed for

implementation?

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Implementation PGx: How much evidence is needed?

• Randomized Clinical Trial

• Endpoints: safety and efficacy

• Cost-effectiveness

• Observational evidence

• Well powered, well designed

• Including replication studies

• Compare with dose adjustments

• Decreased renal function

• Drug interactions

37 Van Wielen, Pharmacogen 2011;12(9):1231

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Abacavir – HLA-B *5701 screening

• 1,956 patients

• 1:1 randomized: screening versus no screening

• Prevalence HLA-B *5701= 5,6% (109 patients)

• NPV= 100%; PVV= 48%

Mallal, N Engl J Med 2008;358(6):568

7 Questions

•Q5: Is the pharmacogenetic test result

actionable?

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Actionable predictive biomarkers

• Endpoint current PGx

studies:

• OR= 1.90

• (Un)favorable genetic profile

• Increased risk

• Association with ..

• Relationship ..

• …

• Dosing algorithm

• Decision tree

• Scoring system

• Clinical guidelines

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Predictive model: scoring system MTX efficacy in RA

Baseline Variable Score

premenopausal 1 Gender Female

postmenopausal 1

Male 0

Disease activity DAS at baseline 3.8 0

DAS at baseline >3.8, but 5.1 3

DAS at baseline >5.1 3.5

Immunological factors Rheumatoid factor negative and non - smoker 0

Rheumatoid factor negative and smoker 1

Rheumatoid factor positive and non - smoker 1

Rheumatoid factor positive a nd smoker 2

Genetic factors MTHFD1 1958 AA genotype 1

AMPD1 34 CC genotype 1

ITPA 94 A - allele carrier 2

ATIC 347 G - allele carrier 1

Other ge notypes 0

Baseline Variable Score

premenopausal 1 Gender Female

postmenopausal 1

Male 0

Disease activity DAS at baseline 3.8 0

DAS at baseline >3.8, but 5.1 3

DAS at baseline >5.1 3.5

Immunological factors Rheumatoid factor negative and non - smoker 0

Rheumatoid factor negative and smoker 1

Rheumatoid factor positive and non - smoker 1

Rheumatoid factor positive a nd smoker 2

Genetic factors MTHFD1 1958 AA genotype 1

AMPD1 34 CC genotype 1

ITPA 94 A - allele carrier 2

ATIC 347 G - allele carrier 1

Other ge notypes 0

≤

≤

Wessels, Arthritis & Rheum 2007;56(6):1765

Sum of score = ……………………………………………………...

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Good clinical response

Good clinical

response (proportion

at t= 6 months)

Wessels, Arthritis & Rheum 2007;56(6):1765

7 Questions

•Q6: Is pharmacogenetic testing feasible?

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Costs

$1

$10

$100

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$1.000.000.000

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Wetterstrand KA. www.genome.gov/sequencingcosts

Genotyping technology

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Taqman

Pyrosequenching

High Resolution Melting

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DNA-chip technology

Amplichip

33 CYP2D6 variants

3 CYP2C19 variants DMET-Plus array

Drug Metabolizing Enzymes and Transporters

1,936 variants in 225 genes

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Affymetrix fluidic station 450Dx en Scanner 3000Dx

Pharmacogenetic service: genotyping and consult

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http://www.lumc.nl/con/3092/

Do patients want PGx screening?

• Feasibility of pharmacy-initiated

pharmacogenetic screening for CYP2D6

and CYP2C19 in primary care setting

• Polypharmacy patients; >60 yrs

• Screening; no ADE

• Provided informed consent: 58.1%

• DNA extraction (Oragene®): 83.3%

• Call rate:

• 93.3% CYP2D6

• 100% CYP2C19

• Guideline application dispensing records:

100%

49 Swen, Eur J Clin Pharmacol 2011, 8 Oct

7 Questions

•Q7: Where do I find up to date information

for interpretation of pharmacogenetic test

results?

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Adoptation of PGx by US Physicians: National survey

• To benchmark physicians’ level

of knowledge and extent of use

of PGx testing

• 397,832 questionnaires

• 10,303 respondents

• 97.6% agreed that genetic

variations may influence drug

response

• 10.3% felt adequately informed

about PGx

• 29% had received any PGx

education

• 12.9% had ordered a PGx test

(6 mo)

Stanek, Clin Pharmacol Ther 2012;91(3):450

Difficulties in interpretation

• One gene – one drug

• TPMT – mercaptopurine

• UGT1A1 – irinotecan

• HLA *5701 - abacavir

• One gene – many drugs

• CYP2D6, CYP2C19

• polypharmacy

• More genes – one drug

• Tricyclic antidepressants

• More genes – many drugs

• Pharmacological knowledge

clinical pharmacist

• Drug metabolism, interactions

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Pharmacists’ expectations towards pharmacogenetics

• To describe the expectations, opinions

and concerns of pharmacists

• Survey 284 pharmacists in Quebec

(Canada)

• 59% community pharmacy

• 28% hospital pharmacy

• 95.6% would be willing to

recommend testing

• 7.7% currently felt comfortable

advising patients

• 96.6% would like to undertake

education on pharmacogenetics

53 De Denus, Pharmacogenomics 2013;14(2):165

Pharmacists?

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Level of Evidence and Clinical Relevance gene-drug interaction

Swen, Clin Pharmacol Ther 2008;83(5):781-8

Swen et al, Clin Pharmacol Ther. 2011 ;89(5):662

Discharge recipe

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Clinical rule DPYD genotyping

New Prescription

Capecitabine, 5-Fluorouracil,

Tegafur?

Pop up: Please send bloodsample to

pharmacy for DPYD genotyping

Result genotyping DPYD*2A

(rs3918290)

PM Prescribe an alternative drug

IM Reduce the starting dose to

50%; then dose intensification

upon toxicity

EM Standard dose

Yes

Yes

Former prescription for

Capecitabine, Fluorouracil, Tegafur?

No

Yes

Is DPYD*2A

genotype known?

Is DPYD*2A

genotype known?

No

Yes

Rule not applicable No

No

Yes

www.pharmgkb.org

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Dosing

guidelines

Dutch Pharmacogenetics Working Group

www.pharmgkb.org

How did we start pharmacogenetics in Leiden?

• Research driven

• Oncology and rheumatology

• Grant applications

• Publications

• Laboratory for Experimental and Clinical Pharmacogenetics

• Molecular biologist

• Assistant professor in pharmacogenetics

• Implementation clinical practice

• Development guidelines for interpretation tests

• Promoting testing in the clinic

• Electronic prescribing (ordering tests, medication surveillance)

• Education

• Training pharmacists, students

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Personal view for PGx (germline) testing recommendations

• TPMT – thiopurines

• CYP2C19 – clopidogrel

• CYP2C9-VKORC1 – coumarines

• DPYD – 5FU/capecitabine

• HLA-B – abacavir/carbamazepine

• G6PD – rasburicase

• UGT1A1 – irinotecan

• IL28B – pegintron

• SLCO1B1 – statine + spierpijn

• CYP2D6 – tamoxifen

• CYP3A5 - tacrolimus

• If I was a patient

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Conclusions

• Drug response is a heritable trait

• Biomarkers are needed for predicting drug response

• Polygenetic markers in both the PK and PD predispose for toxicity and

efficacy

• To increase the explained variance genetic markers should be combined

with other determinants of drug response

• Pharmacogenetic studies should report actionable results

• Observational evidence from well designed and replicated studies may be

acceptable to adjust the dose

• Pharmacogenetics is feasible in the clinic and well accepted by patients and

physicians

• Pharmacogenetic guidelines for interpretation of test results are available

• There is an opportunity for clinical pharmacists to fulfill a new clinical role as

an expert in PGx

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Thanks to

Dr Tahar van der Straaten

Laboratory for Experimental

and Clinical Pharmacogenetics

Prof dr Tom Huizinga Prof dr Hans Gelderblom

Dr Jesse Swen

Backup slides

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7 Questions

•Q6b: Is pharmacogenetic testing feasible

in the pharmacy department?

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Clinical Pharmacy & Toxicology LUMC

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New GMP-facility (2012)

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Cinical Pharmacy & Toxicology LUMC

Clinical Pharmacy

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Bachelor Pharmacy

4 years

Master Pharmacy

2 years

Pharmacist (PharmD)

Hospital Pharmacy

4 years (zaio)

Clinical Pharmacist

Hospital Pharmacy

6 years (zapiko)

Clinical Pharmacist

(PharmD PhD)

Clin. Pharmacology – 1 year

Clin. Pharmacist/ Clin. Pharmacol.

Clinical Pharmacy Department

• Drug dispensing

• In patients

• Out patients

• Drug Manufacturing

• Laboratory

• QC/Drug levels-PK/Toxicology

• Pharmacogenetics

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Integration of

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expertise in clinical pharmac(olog)y in the framework of

Patient Care and Research

Identification – In depth analysis mechanisms – Translation to patient care

Typical PhD thesis – Jan Pander PharmD PhD

• Pharmacogenetics of advanced colorectal cancer treatment

• National CAIRO2 study

• PGx of EGFR and VEGF inhibition

• Clinical PGx association studies

• Pathway candidate gene approach

• GWAS study

• Translation to patient care

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Typical PhD thesis – Jan Pander PharmD PhD

• Methodological

• Gene-gene interaction analysis in PGx

• Preclinical mechanistic studies

• Activation of tumor-promoting type 2 macrophages by cetuximab

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