national cancer institute milan, italy university of milano bicocca, monza, italy molecular...

National Cancer Institute Milan, Italy

University of MilanoBicocca, Monza, Italy

Molecular Mechanisms of Molecular Mechanisms of Resistance to Imatinib Resistance to Imatinib (STI571, CGP57148B)(STI571, CGP57148B)



Structure of Imatinib Structure of Imatinib (STI571, CGP 57148B)(STI571, CGP 57148B)

Class: Phenylaminopyrimidines, 589.7 mwClass: Phenylaminopyrimidines, 589.7 mw

CH3SO3H

O



Cellular Selectivity of STI571: Cellular Selectivity of STI571: ICIC5050[µM][µM]

Kinases InhibitedKinases Inhibited Kinases Not InhibitedKinases Not Inhibitedv-ABLv-ABL 0.1–0.30.1–0.3 Flt-3Flt-3 >10 >10

p210p210bcr-ablbcr-abl 0.250.25 c-Fms, v-Fmsc-Fms, v-Fms >10 >10

p185p185bcr-ablbcr-abl 0.250.25 EGF receptorEGF receptor >100 >100

TEL-AblTEL-Abl 0.350.35 c-erbB2c-erbB2 >100 >100

PDGF receptorPDGF receptor 0.10.1 Insulin receptor >100Insulin receptor >100

TEL-PDGF TEL-PDGF IGF-1 receptor >100IGF-1 receptor >100

receptorreceptor 0.150.15 v-Srcv-Src >10 >10

c-kitc-kit 0.10.1 JAK-2JAK-2 >100 >100

Druker BJ et al. Nat Med. 1996;2:561-566; Personal communication 4/00. B Druker, E Buchdunger.



Effect of STI571 on Growth ofEffect of STI571 on Growth ofBcr-Abl–Positive and –Negative Cell LinesBcr-Abl–Positive and –Negative Cell Lines

Gambacorti-Passerini C et al. Blood Cells Mol Dis. 1997;23:380.

*Bcr-Abl-negative cell lines

†Bcr-Abl-positive cell lines

U937*KG1*KCL22*K562†

KU812†

SU DHL1†

STI571 Concentration (M)

% Control CPM

0 0.1 0.3 1 3 10

0

20

40

60

80

100

120



LAMA84 Control

LAMA84 24h 1uM

LAMA84 44h 1 uM



Cytogenetic response of Chronic Phase patients during XXII therapy month

% patients without response

(20%)

% patients with major response(13,33%)

% patients with complete response(66,67%)



Chronic Phase patients

30.00

20.0023.08

45.16

32.0028.57

44.83

30.00

96.77

76.9280.00

70.0073,68

54.84 55.17

71.43 68.00

3.230.00

20.00

40.00

60.00

80.00

100.00

0 3 6 9 12 15 18 21 24

Therapy, month

% p

ati

en

ts

% pt without response % pt with major or complete response



Cytogenetic response of Accelerated Phase patients during XXII therapy month

% patients with complete response(35,71%)

% patients with major response

(0%)

% patients without response(64,29%)



Hematological Response in Blast Crisis patients

00.00

25.00

100.00

75.00

0000

44.44

66.67

44.44

55.56

33.33

55.56

1

11

21

31

41

51

61

71

81

91

1 21 41 61 81 101 121 141 161

Giorni di terapia

% p

azie

nti

% pt con risposta completa % pt con risposta parziale % pt senza risposta



Hematologic failureCytogenetic failureIFN intolerant

= Censored observations

% w

ithou

t los

s of

MC

yR

0

10

20

30

40

50

60

70

80

90

100

Months since MCyR0 3 6 9 12 15 18 21 24 27 30 33 36 39 42



Resistance to ImatinibResistance to Imatinib



Cytogenetic and hematological response of patient 506

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10 11 12Therapy, month

% of Ph+ cells WBC (* 1000) % of blasts PLT(*1000)



IIDiscontinuous InhibitionDiscontinuous Inhibition



0

20

40

60

80

100

120

140

ctrl 6h 7h 20h 21h 30h 30h

time of drug exposure

% c

pm



bcr/abl

bcr/abl

anti-phosphotyrosine

anti-abl

i.p. 2h p.o. i.p. 5h p.o. i.p. 9h p.o.



0

1

2

3

4

5

6

7

8

9

0 10 20 30 40

days

tumor weight mg x 1000 ctrl

2x50 mg/kg i.p.



0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15 20

days

tumor weight mg x 1000

ctrl

3x160 mg/kp p.o.



0102030405060708090

100

0 10 20 30 40 50days

tumor free survival

ctrl

3x50 mg/kg i.p.

3x160 mg/kg p.o.



IIIIInsufficient Tissue LevelsInsufficient Tissue Levels

(Beware of Plasma Concentrations)(Beware of Plasma Concentrations)



1 2 3 4

alpha 1 acidic glycoprotein



AGP

0

20

40

60

80

100

120

0 0.5 1 1.5 2 2.5 3

µM STI571

% o

f co

ntr

ol 0 mg/ml

0.1 mg/ml

0.2 mg/ml

0.4 mg/ml

0.8 mg/ml

1 mg/ml

2 mg/ml



205 kd Anti-Abl

205 kd Anti-Ptyr

Day 1 Day 5

Patient 001

205 kd

47 kd

Day 1

Anti-Ptyr

Day 2

Anti-Actin

Patient 504



Day 1 Relapse

No

ST

I571

in v

ivo

> 3

µM

ST

I571

in v

ivo

+ 3

µM

S

TI5

71In

vit

ro

+ 3

µM

ST

I571

in v

itro

205 kd

Anti-Abl

Anti-Ptyr

Patient 001

205 kd

Patient 505

Anti-Abl

Anti-Ptyr

Patient 002

Anti-Abl

Anti-Ptyr

205 kd

205 kd

205 kd

205 kd



>3 µM S

TI571 in vivo +

100 µM E

ryth

rom

ycin

in vitr

o

>3µM S

TI571 in vivo

3 µM S

TI571 in vitr

o

205 kd

205 kd

Patient 008

Anti-Abl

Anti-Ptyr

Patient 009

Anti-Abl

Anti-Ptyr

>3 µM S

TI571 in vivo +

100 µM E

ryth

rom

ycin

in vitr

o

>3µM S

TI571 in vivo

3 µM S

TI571 in vitr

o

205 kd

205 kd



Effect of the administration of Clindamycin (900 mg i.v. over 20 minutes) on STI571 plasma concentrations

0 10 20 300.0

0.1

0.2

0.3

0.4

Patient 008Patient 00213

Patient 00241

2

3

4

5

6

7

8

Time (min)

ST

I571

Pla

sma

con

cen

trat

ion

(g

/ml)

ClindamycinClindamycin



0 4 8 12 16 20 240

1

2

3

4

5

6

7

8

9001 day 4502 day 4

Time (h)

STI

571

conc

entr

atio

n(

g/m

l)

0 1 2 3 40

1

2

3001 day 5502 day 5

4 8 12 16 20 24

Time (h)

0 4 8 12 16 20 240.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5002 day 4503 day 4502 day 4

Time (h)

STI

571

conc

entr

atio

n(

g/m

l)

0 1 2 3 40.0

0.5

1.0

1.5002 day 5503 day 5501 day 5

6 10 14 18 22

Time (h)

Effect of Clindamycin (C) administration Effect of Clindamycin (C) administration on steady state STI571 plasma levelson steady state STI571 plasma levels



BCR/ABL

STI571STI571



BCR/ABL

AGP

STI 571

AGP

STI 571

AGP

STI 571

AGP

STI 571

In the presence of alpha 1 acidic glycoprotein (AGP)

STI571STI571



Trattamento con STI571 + Eritromicina (E)

BCR/ABL

STI 571

STI 571

STI 571

STI 571

AGP

AGP

AGP

AGPE

E

E E

national cancer institute milan, italy university of milano bicocca, monza, italy molecular...

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