C. Lieu, H. Tran, Z. Jiang, M. Mao, M. Overman, C. Eng, J. Morris, L. Ellis, J. Heymach, and S. Kopetz

Departments of Gastrointestinal Medical Oncology, Surgical Oncology, and Head and Neck/Thoracic Medical Oncology

The University of Texas MD Anderson Cancer Center

The Association of Alternate VEGF Ligands With Resistance to Anti-VEGF Therapy in Metastatic

Colorectal Cancer

Cell membrane

VEGF-A

VEGF-R1(Flt-1)

MigrationInvasionSurvival

VEGF-R3(Flt-4)

Lymphangio-genesis

VEGF-R2(KDR/Flk-1)Proliferation

SurvivalPermeability

PlGF VEGF-C, VEGF-D

Fun

ctio

ns

VEGF Biology

Y

Bevacizumab

Adapted from Bergers et al. Nat Rev Cancer. 2008;8:592-603.

VEGF-A VEGF-A

X

VEGF-

C

VEGF-D PlGF

Baseline Treatment with bevacizumab

AngiogenesisRestored

VEGF-A

X

Hypothesis: Alternate VEGF ligands are associated with the resistance to anti-VEGF therapy in patients with metastatic colorectal cancer

Study Design

Prospective Clinical Trial· Phase II trial of FOLFIRI +

bevacizumab in patients with metastatic colorectal cancer

· Forty-three patients enrolled· Intensive cytokine measurements

Retrospective Validation Cohort· The Texas Genetic Consortium

database (n = 710)· Heterogeneous treatment

histories· Single cytokine measurement

PD

PD

PD

Study Design

Prospective Clinical Trial· Phase II trial of FOLFIRI +

bevacizumab in patients with metastatic colorectal cancer

· Forty-three patients enrolled· Intensive cytokine measurements

Retrospective Validation Cohort· The Texas Genetic Consortium

database (n = 710)· Heterogeneous treatment

histories· Single cytokine measurement

PD

PD

PD

Prospective Cohort: PlGF Increased Prior to Progression

Kopetz et al. J Clin Oncol 28:453-459

0

20

30

40

ULN

p<0.001*

p<0.001*

p<0.01*

PlG

F (

pg

/mL

)

Bas

elin

e

Post

Bev

Post

FOLFIR

I

Firs

t Res

tagin

g

Sec

ond Res

tagin

g

Prior t

o Pro

gress

ion

Progre

ssio

n

0

500

1000

1500

2000

2500V

EG

F-C

(p

g/m

L)

ULN

*

*

* p<0.05 by Mann Whitney U test

Prospective Cohort: VEGF-C Increased Prior to Progression

Bas

elin

e

Post

Bev

Post

FOLFIR

I

Firs

t Res

tagin

g

Sec

ond Res

tagin

g

Prior t

o Pro

gress

ion

Progre

ssio

n

0

100

200

300

400

VE

GF

-D (

pg

/mL

)

ULN

Prospective Cohort: VEGF-D Minimally Increased at Progression

*

* p = 0.04

Study Design

Prospective Clinical Trial· Phase II trial of FOLFIRI +

bevacizumab in patients with metastatic colorectal cancer

· Forty-three patients enrolled· Intensive cytokine measurements

Retrospective Validation Cohort· The Texas Genetic Consortium

database (n = 710)· Heterogeneous treatment

histories· Single cytokine measurement

PD

PD

PD

· Separated patients into three groups:- Patients presenting prior to frontline therapy- Patients treated with chemotherapy without bevacizumab - Patients treated with chemotherapy and bevacizumab

· To minimize heterogeneity, samples were matched for:- Metastatic disease sites- Chemotherapy cycles- Time from last chemo to plasma collection

· 533 patients were included in the analysis

Retrospective Cohort

PlGF Elevated After Bevacizumab

No Treatment Chemo Only Chemo+Bev0

20

40

60

80

Group

Co

nce

ntr

atio

n,

pg

/mL

ULN

p < 0.0001

p < 0.0001

No Chemo Chemo Only Chemo+Bev0

500

1000

1500

Group

Co

nce

ntr

atio

n,

pg

/mL

ULN

VEGF-C Elevation Unable to be Confirmed

p < 0.0001

p = 0.64

No Chemo Chemo Only Chemo+Bev0

100

200

300

400

500

Group

Co

nce

ntr

atio

n,

pg

/mL

ULN

p < 0.0001

Minimal VEGF-D Elevation Confirmed

Summary

PlGF

VEGF-C

VEGF-D

Prospective Retrospective Conclusions

Basel

ine

After B

evac

izum

ab

After F

OLFIRI+

B

Prior t

o Pro

gress

ion

Progre

ssio

n

0

20

30

40

ULN

p<0.001*

p<0.001*

p<0.01*

PlG

F (

pg

/mL

)

No Treatment Chemo Only Chemo+Bev0

20

40

60

80

Group

Co

nce

ntr

atio

n,

pg

/mL

ULN

Bas

elin

e

Post

Bev

Post

FOLFIR

I

Firs

t Res

tagin

g

Sec

ond Res

tagin

g

Prior t

o Pro

gress

ion

PD

0

500

1000

1500

2000

2500

VE

GF

-C (

pg

/mL

)

ULN

No Chemo Chemo Only Chemo+Bev0

500

1000

1500

Group

Co

nce

ntr

atio

n,

pg

/mL

ULN

Bas

elin

e

Post

Bev

Post

FOLFIR

I

Firs

t Res

tagin

g

Sec

ond Res

tagin

g

Prior t

o Pro

gress

ion

PD

0

100

200

300

400

VE

GF

-D (

pg

/mL

)

ULN

No Chemo Chemo Only Chemo+Bev0

100

200

300

400

500

Group

Co

nce

ntr

atio

n,

pg

/mL

ULN

1) PlGF is elevated after FOLFIRI+B

2) A similar elevation was seen after chemotherapy + bev but not after chemotherapy alone

1) VEGF-C is elevated after FOLFIRI+B

2) No difference was seen in the second cohort between the two “post-therapy” groups

3) Limitations include heterogeneity and high inter-patient variability

1) Modest elevations in VEGF-D were seen after FOLFIRI+B

2) Elevations were seen in the “post-therapy” groups but not impacted by bevacizumab therapy

How long do PlGF and VEGF-D stay elevated after bevacizumab?

Time from last bevacizumab dose (mo)

VE

GF

-D (

pg

/mL

)0 1 2 3 4 5 6

0

100

200

300

400

500

600

700VEGF-D T1/2 = 1.5 months

(95% CI: 1.2 - 2.0)

Time from last bevacizumab dose (mo)

PlG

F (

pg

/mL

)

0 1 2 3 4 5 60

20

40

60

80

100

120PlGF T1/2 = 1.6 months

(95% CI: 1.4 - 1.9)

No temporal change in PlGF and VEGF-D in patients treated with chemotherapy only

Limitations of Cytokine Analysis

· How well do circulating levels of VEGF ligands reflect the tumor microenvironment?- Or host response?

· Difficult to place magnitude of changes into context- What degree of elevation would be necessary to evoke a biologic

response

· Association vs. Causation- Are alternate VEGF ligands driving resistance to bevacizumab

· Return to preclinical models· Clinical trial

VEGF-APlGF VEGF-C, VEGF-D

Large molecule VEGF inhibitors

Y

Bevacizumab

YVGX-100

YRamucirumab(IMC-1121B) II

CT-322

Y

IMC-18F1

Aflibercept (VEGF Trap)Y

TB403

Phase III VEGF-Trap (Aflibercept) after Bevacizumab

2nd line CRC (after treatment with

oxaliplatin-based therapy)

N=1200 patients

Primary endpoint: OS

R

FOLFIRI + Placebo

FOLFIRI + Aflibercept 4mg/kg

“VELOUR” StudyPrimary endpoint OS met

Conclusions

· VEGF family ligands other than VEGF itself are associated with bevacizumab-containing chemotherapy resistance in mCRC

· Plasma levels of PlGF are increased prior to radiographic progression of disease

· Changes in VEGF-C were not able to be validated- Limited by technical concerns in the validation cohort

· VEGF-D is minimally increased at the time of progression- Unclear biologic significance

· Further study of agents targeting multiple VEGF-ligands are ongoing

Acknowledgments

· GI Medical Oncology- Scott Kopetz- Karen Mao- Camilla Ziang- James Abbruzzese

· Thoracic/H&N Medical Oncology- Hai Tran- John Heymach- Stef Fiorentino

· GU Medical Oncology- Gary Gallick

· Funding- ASCO Cancer Foundation

Young Investigators Award- Circadian Technologies- T32 Training Grant

Plasma PlGF in mCRC

· In a prospective cohort, plasma PlGF levels are elevated prior to progression and at the time of progression on a bevacizumab regimen

· In a validation cohort, compared with untreated patients and patients who have received chemotherapy only, patients who have received chemotherapy and bevacizumab had elevated levels of PlGF

· These changes appear specific to patients receiving bevacizumab

0

20

30

40

ULN

p<0.001*

p<0.001*

p<0.01*

PlG

F (

pg

/mL

)

Lieu et al. ASCO 2011 Abstract #3533

Lieu et al. ASCO 2011 Abstract #3533