Clinical implications of pharmacogenetic research

S:t Petersburg April 4, 2008

Professor Leif BertilssonDept. of Clinical PharmacologyKarolinska University Hospital, HuddingeSweden

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Pharmacogenetics

Pharmacogenomics

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Drug transporters

Drug metabolising enzymes

Drug receptors

Drug receptor effectors

Drug response

Polymorphic impact on drug response

Drug

Metabolites

+

+++

+

+

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* Five probe drugs in the cocktail developed at Karolinska Institutet

CarbamazepinePhenytoinRifampicin

Ketoconazole

ErythromycinMidazolamQuinine*

AlprazolamCyclosporine ADiazepamTriazolam

CYP3A4

ArtemisininRifampicinTobaccosmoking

Inducers

ParoxetineQuinidine

FluvoxamineSulphaphena-zole

FluvoxamineInhibitors

Debrisoquine*Sparteine

MephenytoinOmeprazole*

Losartan*Caffeine*Melatonin

Markerdrugs

Most antidepressantsMost antipsychoticsCodeineMetoprolol

CitalopramDiazepamOmeprazoleProguanil

PhenytoinTolbutamideWarfarin (S)

AmitriptylineClomipramineClozapineFluvoxamine

Substrates

CYP2D6CYP2C19CYP2C9CYP1A2

The major human drug metabolising cytochrome P450 (CYP) enzymes

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Interethnic differences in the hydroxylation of debrisoquine

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Johansson et al., PNAS 90:1945-51, 1993, Aklillu et al., JPET 278: 441-6, 1996

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Dalén et al, 1998

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Frequency of subjects having duplicated/ multiduplicated CYP2D6 genes

Sweden 1-2 %Dahl et al, 1995Denmark 0.8 %Bathum et al, 1998Germany 3.6 %Sachse et al, 1997Spain (Badajoz) 7.0 %Agundez et al, 1995Spain (Zaragoza) 10 % Bernal et al, 1998Saudi Arabia 20 % McLellan et al, 1997Ethiopia 29 % Aklillu et al, 1996Los Angeles, USA

Caucasians 4.3 %London et al, 1997African-Americans 4.9 %London et al,

1997

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Prevalence of the CYP2D6 genotypes in 81 depressed Swedish patients refractory to

treatment with CYP2D6 substrateantidepressant drugs

81 (100%)All

8 (9.9%)Duplication

2 (2.5%)PM

71 (87.6%)EM

Number of patientsCYP2D6 genotype

Kawanishi et al 2004

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* Five probe drugs in the cocktail developed at Karolinska Institutet

CarbamazepinePhenytoinRifampicin

Ketoconazole

ErythromycinMidazolamQuinine*

AlprazolamCyclosporine ADiazepamTriazolam

CYP3A4

ArtemisininRifampicinTobaccosmoking

Inducers

ParoxetineQuinidine

FluvoxamineSulphaphena-zole

FluvoxamineInhibitors

Debrisoquine*Sparteine

MephenytoinOmeprazole*

Losartan*Caffeine*Melatonin

Markerdrugs

Most antidepressantsMost antipsychoticsCodeineMetoprolol

CitalopramDiazepamOmeprazoleProguanil

PhenytoinTolbutamideWarfarin (S)

AmitriptylineClomipramineClozapineFluvoxamine

Substrates

CYP2D6CYP2C19CYP2C9CYP1A2

The major human drug metabolising cytochrome P450 (CYP) enzymes

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Similarity among the CYP3A proteins

CYP3A5 CYP3A7 CYP3A43

CYP3A4 84.1 88.1 75.8CYP3A5 *** 81.9 75.8CYP3A7 *** 71.5CYP3A43 ***

Gellner et al 2001

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Plasma concentrations of cholesterol and 4-hydroxycholesterol in patients treated with different antiepileptics 

Antiepileptic drug Cholesterol 4Hydroxycholesterol

  nmol/l ng/ml

Valproate (n = 15) 4.5 0.8 28 15

Carbamazepine (n = 15) 5.8 1.5 240 142

Phenytoin (n = 10) 5.1 1.0 214 154

Phenobarbital (n = 5) 4.9 1.1 239 226

 

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4β-Hydroxycholesterol in three populations

Mean Mean±SE Mean±SD

T AN SW E KO R

population

10

15

20

30

40

50

60

4β-hydroxycholesterol (ng/m

L)

n= 138 n= 159 n= 149

p<0.000001 p<0.01

p<0.000001

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Haplotype frequencies

*3

6986A>G

*6

14690>A

*7

27131-27132insT

Swedes Koreans Tanzanians

CYP3A5*1 A G T 0.07 0.17 0.53

CYP3A5*3 G* G T 0.93 0.80 0.17

CYP3A5*6 A A* T - - 0.18

CYP3A5*7 A G TT* - - 0.12

CYP3A5*3 + *7 G* G TT* - 0.03

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Impact of CYP3A5 on 4β-hydroxycholesterol

Number of CYP3A5*1 alleles

Mean Mean±SE Mean±SD

0 1 2 0 1 2 0 1 2

10

15

20

30

40

5060

4β-h

ydro

xych

oles

tero

l (ng

/mL)

Tanzanians (136) Swedes (136) Koreans (146)

p<0.000001

p<0.000001

p<0.00001

p<0.000001

p<0.0001 p<0.005

p<0.005

n=36 67 33 117 18 1 98 43 5

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* Five probe drugs in the cocktail developed at Karolinska Institutet

CarbamazepinePhenytoinRifampicin

Ketoconazole

ErythromycinMidazolamQuinine*

AlprazolamCyclosporine ADiazepamTriazolam

CYP3A4

ArtemisininRifampicinTobaccosmoking

Inducers

ParoxetineQuinidine

FluvoxamineSulphaphena-zole

FluvoxamineInhibitors

Debrisoquine*Sparteine

MephenytoinOmeprazole*

Losartan*Caffeine*Melatonin

Markerdrugs

Most antidepressantsMost antipsychoticsCodeineMetoprolol

CitalopramDiazepamOmeprazoleProguanil

PhenytoinTolbutamideWarfarin (S)

AmitriptylineClomipramineClozapineFluvoxamine

Substrates

CYP2D6CYP2C19CYP2C9CYP1A2

The major human drug metabolising cytochrome P450 (CYP) enzymes

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Inhibition of metoprolol metabolism and potentiation of

its effects by paroxetine in routinely treated patients with

acute myocardial infarction (AMI)

Ksenia Goryachkina, Aleksandra Bubello, Svetlana Boldueva,

Svetlana Babak, Ulf Bergman, Leif Bertilsson

Eur. J. Clin. Pharmacol. 2008;64:275-282

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Methods:•187 patients (61% men, age 60±11 years (36-85) with confirmed AMI•CYP2D6 *3,*4, and gene duplication •Metoprolol and α-hydroxy metoprolol concentrations were measured in plasma 0,2,6 and 12 hours after metoprolol intake •Heart rate and blood pressure was measured at the times of sampling•Clinical variables were taken from case histories (baseline and discharge heart rate, metoprolol dose at discharge, concomitant diseases, severity of AMI, heart failure etc)

0 1 2 340

50

60

70

80

90

dis

char

ge

HR

b/m

in

number of functional CYP2D6 alleles

Heart rates on the adjusted metoprolol dosewere higher with more functional alleles (p<0.05)

Pharmacodynamics:Pharmacokinetics:

0 1 2 31

10

100

1000

10000

number of functional CYP2D6 alleles

met

opro

lol c

once

ntra

tion

AU

CnM

ol*h

/mg/

kg

Metoprolol plasma concentration AUCIs determined by CYP2D6 genotype

P<0.001

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Goryachkina et al, 2008

0 1 2 3 4 5 6 7 8 9 10 11 120

100

200

300

**

****** **

before paroxetine

on paroxetine

-hydroxy metoprolol

0 1 2 3 4 5 6 7 8 9 10 11 120

200

400

600

on paroxetine

before paroxetine

**

*****

**

metoprololP

lasm

a c

on

cen

trati

on

nM

/mg

/kg

Hours post dose

0 1 2 3 4 5 6 7 8 9 10 11 1250

55

60

65

70

75

80

* *

* *

* * *

on paroxetine

before paroxetine

hours post-dose

me

an

he

art

ra

te

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Active CYP2D6 genes in AMI patients withoutventricular rhythm disturbances (VRD) (n=177)and with VDR (N=23) in hospitalized Russian patients

Goryachkina et al, 2008

CYP2D6 duplication 4/173 (2 %) 5/18 (22 %)

p = 0.0002

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Bertilsson et al: Debrisoquine hydroxylation and personality, Lancet 1989

Poor hydroxylators had significantly lower scores in the Karolinska psychasthenia scale (p<0.05) and had a higher frequency of extreme responses (p<0.01) than extensive hydroxylators. Low psychasthenia scores imply high vitality, alertness, efficiency, and ease of decision-making. The poor hydroxylators’ lack of hesitation was also reflected in the more frequent choice of extremes. These personality characteristics agreed well with the impression we had before our study.