1. Angiogenesis: Using Old and New Approaches
John Mackey, MD
Professor of Oncology
University of Alberta
Edmonton, Canada

2. Faculty Disclosure
John R. Mackey, MD, FRCP (C), has disclosed that he has received consulting fees from Eli Lilly and Roche and CME honoraria from Amgen.

3. Overview Angiogenesis and the VEGF/VEGF-R pathway
New mechanisms and new agents
The metastatic / adjuvant gulf
Toward predictive biomarkers

4. Angiogenesis Physiologic process of new blood vessel formation
Principally driven by interactions between vascular endothelial growth factors and 3 high-affinity VEGF receptors
Folkman J. Semin Oncol. 2002;29(suppl 6):15-18.
Hicklin DJ, et al. J Clin Oncol. 2005;23:

5. Y VEGF Family of Ligands and Receptors Source needed Vasculogenesis
VEGF- A121
VEGF- A145
VEGF- A165
VEGF- A189
VEGF- A206
VEGF- B167
VEGF- B186
PlGF- 1,2
VEGF- C
VEGF- D
VEGF- E Y
s-s
s-s
Source needed
VEGFR-1
(Flt-1)
NRP-1
VEGFR-2
(Flk-1/KDR)
VEGFR-3
(Flt-4)
NRP-2
Vasculogenesis
Angiogenesis
Lymphangiogenesis

6. An Obvious Target . . .
(the cell)

7. Agents Targeting the VEGF Pathway
VEGF-A
Anti-VEGFR2 antibodies (ramucirumab)
Anti-VEGF antibodies (bevacizumab)
Soluble VEGF receptors (aflibercept)
VEGFR-1
VEGFR-2
VEGFR-3
PlGF, placenta growth factor. P P P P P P
Endothelial cell
Agents in yellow = FDA approved
Small-molecule inhibitors of VEGFR (PTK-787, AZD2171, motesanib, sunitinib, sorafenib, pazopanib, axitinib, others)
Ferrara et al. Nat Med. 2003;9:669.

8. Agents Targeting the VEGF Pathway
Anti-VEGF antibodies
Bevacizumab
Anti–VEGFR-2 antibodies
Ramucirumab (IMC-1121B)
Soluble VEGF receptors
Aflibercept (VEGF Trap)
Small-molecule VEGFR inhibitors
Vatalanib (PTK787)
AZD2171
Sunitinib (SU11248)
Sorafenib (BAY )
Motesanib (AMG 706)
Pazopanib AG
Others

9. Antiangiogenic Risk:Benefit Ratio
Toxicity
Efficacy

10. Antiangiogenic Class Toxicities
Hypertension
Clotting
Bleeding
Congestive heart failure (when combined with anthracyclines)
Financial
Agent-specific toxicities
Motesanib: cholecystitis
Pigmentation changes: sunitinib, pazopanib
Gressett SM, et al. Ann Pharmacother. 2009;43: Blumenschein GR Jr, et al. Ann Oncol. 2011;[Epub ahead of print]. Rosenbaum SE, et al. Support Care Cancer. 2008;16: Bible KC, et al. Lancet Oncol. 2010;11:

11. Therapeutic Efficacy Modest, in general … Colorectal carcinoma – M1
Non-small-cell lung carcinoma – M1
Renal cell carcinoma – M1
Breast cancer – M1
No evidence of adjuvant efficacy thus far
2 negative studies in M0 CRC (C-08, AVANT)

12. Adjuvant Antiangiogenic Therapy?

13. Bevacizumab Best studied agent
Modest efficacy in a number of indications
Resistance mechanisms
Upregulation of ligand
Insoluble VEGF remains and promotes angiogenesis?[1]
VEGFR-1 polymorphisms (constitutive activation)?[2]
No validated predictive marker
Potential high serum VEGF levels?
1. Chen TT, et al. J Cell Biol. 2010;188:
2. Lambrechts D, et al. ECCO-ESMO Abstract 16LBA.

14. New Data on Newer Agents
Ramucirumab
Aflibercept

15. Spratlin and Mackey. Future Oncol. 2010;6:1085-1094.
Ramucirumab
Fully humanized antibody directed against the VEGFR-2
Potential for immune-mediated destruction of angiogenic vessels
Circumvents insoluble VEGF activation of VEGFR-2
In phase II trials for MBC, advanced GI cancers, metastatic GU cancers, recurrent ovarian cancer, prostate cancer, metastatic RCC
In phase III trials for refractory metastatic gastric adenocarcinoma, advanced NSCLC, relapsed hepatocellular carcinoma, metastatic CRC
Spratlin and Mackey. Future Oncol. 2010;6:

16. TRIO-012 Ramucirumab Study
Patient population
Women with HER2-negative, unresectable, locally recurrent or metastatic breast cancer with or without measurable lesions
No previous chemotherapy for metastatic or locally recurrent and inoperable breast cancer
Study plan
Progressive
disease Or
unacceptable
toxicity
withdrawn
consent
Docetaxel 75 mg/m² IV q3w
RANDOMIZATION
…..
2/3
F/UP
Blinded ramucirumab 10 mg/kg
IV q3w
Docetaxel 75 mg/m² IV q3w
1/3
…..
Blinded placebo IV q3w
Mackey J, et al. Clin Breast Cancer. 2009;9:

17. Aflibercept
Fusion protein decoy receptor: binds VEGF-A, VEGF-B, and placental growth factor
Achieved primary endpoint (OS) in VELOUR phase III clinical trial for second-line treatment of mCRC
1266 mCRC patients FOLFIRI vs FOLFIRI + aflibercept improved OS
Regeneron [press release]. Available at: Accessed May 25, 2011.

18. Martin MM, et. al. Lancet Oncol. 2011;12:369-376.
Motesanib
Small molecule inhibitor of VEGFR-1, VEGFR-2, VEGFR-3, PDGFR, and KIT
Increases activity of paclitaxel in MBC in randomized phase II setting, but with significant GI toxicity
Martin MM, et. al. Lancet Oncol. 2011;12:

19. TRIO-010 Motesanib Study N = 282 RANDOM I ZAT ON Treatment until
Paclitaxel
90 mg/m² IV weekly for 3/4 wks
Roll-over (optional)
RANDOM I
ZAT ON
Arm A
Open-label motesanib
125 mg PO daily PD
Blinded placebo
PO daily
Paclitaxel
90 mg/m² IV weekly for 3/4 wks
Arm B
Treatment until
Progressive disease
Unacceptable toxicity
Consent withdrawal
Blinded motesanib
125 mg PO daily
Paclitaxel
90 mg/m² IV weekly for 3/4 wks
Arm C
Open-label bevacizumab
10 mg/kg on Week 1 and Week 3
N = 282
Stratified by:
Previous taxane CT vs other vs none
Number of metastatic sites (< 3 vs ≥ 3)
Hormone receptor status (positive vs negative)
Martin MM, et. al. Lancet Oncol. 2011;12:

20. Vascular Disrupting Agents
drugs designed to damage the established vasculature of tumors causing central necrosis
Flavinoid compounds
ASA Phase III (NSCLC)
microtubule destabilizers
CA4P Phase II/III
AVE Phase III; sarcoma)
ABT Phase II (multiple histologies)
Dolastatin Phase II
Oxi Phase I
Due to residual rim of viable cells, combination therapy may be required

21. Angipoietin -TIE Receptor Pathway
TIE-1 and TIE-2 are cell-surface receptors that bind and are activated by angiopoietins (ANGPT1, ANGPT2, and ANGPT4)
Play crucial role in angiogenic switch
Agents targeting ANG1 anad ANGPT2 are in phase II clinical trials and early reports suggest anti-tumor activity and a safety profile distinct from anti-VEGFA agents
Substantial combination benefit of targeting both ANGPT2 and VEGFA pathways preclinically

22. Agents Targeting the ANGPT-TIE Pathway
Compound
Target
Status
AMG-386
ANGPT1 and 2
phase II studies report OS advantage in ovarian CA; phase III PF
ANGPT2
phase II
CEP-11981
TIE2 and VEGF-R
phase I
ANGPT2 aptamer
preclinical

23. How Can We Move Beyond Empiricism?
Predictive assays

24. Therapeutic Predictive Assays
Prognostic biomarker
“How bad is my cancer, Doc?”
Predictive biomarker
“Is this drug going to work?”

25. Exposure Biomarkers
Measure biologic response after administration of the drug
Include:
Treatment-emergent hypertension
Changes in serum VEGF, shed VEGFR-2, PIGF
Changes in dynamic-contrast MRI
Have been useful in defining pharmacodynamically appropriate doses and schedules
Do not address whether or not to start antiangiogenic therapy in a given patient
Rini B, et al. J Natl Cancer Inst. 2011;103: Schneider BP. J Clin Oncol. 2008;26: Vlahovic G, et al. J Thoracic Oncol. 2007;8:S745.

26. Tumor-Based Predictive Markers
Baseline tumor VEGF levels
Prognostic but not predictive
Low levels of carbonic anhydrase IX[1]
Von Hippel-Lindau loss of function mutations in M1 renal cell carcinoma[2]
HER2 positivity in breast cancer
Associated with high levels of VEGF, independently prognostic[3]
1. Hong YS, et. al. BMC Cancer. 2009;9: Choueri et. al. J Urol Konecny GE, et. al. Clin Cancer Res. 2004;10:

27. Blood-Based Biomarkers
Baseline circulating VEGF levels
Variably prognostic, but not predictive[1]
Circulating endothelial cell enumeration
May be prognostic in some malignancies[2,3]
Not yet shown to be predictive
1. Kaseb AO, et al. Cancer. 2009;115: Batchelor T, et al. ASCO Abstract Ramalingam SS, et al. ASCO Abstract 8078.

28. Host-Based Predictive Biomarkers
Angiogenesis is a response of normal stroma to signals from the cancer
Germ-line genetic variability may contribute to efficacy and toxicity
E2100 MBC paclitaxel ± bevacizumab
VEGF-2578AA and VEGF-1154AA genotypes had higher OS in combination[1]
Constitutive activation of VEGFR-1 pathway?[2]
1. Schneider BP, et al. Clin Cancer Res. 2009;15: Lambrechts D, et al. ECCO-ESMO Abstract 16LBA.

29. SNPs Relate to Survival in MBC/ Bevacizumab?
Small subset, tumor DNA, unclear how many SNPs evaluated
Schneider BP, et al. Clin Cancer Res. 2009;15:

30. The State of Published Antiangiogenic Trials
In general . . .
Unselected cancers
Treat entire population with novel therapy
Minimal and/or retrospective tissue collection
Unplanned retrospective subset analysis

31. Ongoing Antiangiogenic Trials . . .
Molecular rationale
Up-front tumor and somatic tissue accrual
Molecular stratification prior to therapy
(If any hint of predictive marker)
Prespecified statistical assessment of biomarker performance

32. Will We Find a Predictive Marker for Antiangiogenic Therapy?
“It’s difficult to make predictions, especially about the future.”

33. A Tale of 2 Trials Adjuvant chemotherapy in operable breast cancer
Standard therapy vs standard therapy + 1 yr of bevacizumab N ~ 3000 patients
ClinicalTrials.gov. NCT
ClincialTrials.gov. NCT

34. Preconditions for a VEGF Pathway Predictive Biomarker
Agent inhibits this pathway
Pretreatment biology drives the therapeutic response
Compensatory non-VEGF–mediated pathways are irrelevant
Randomized clinical trials with appropriate biologic samples
Clinical efficacy signal is sufficiently strong in the sensitive subpopulation to drive a statistically significant interaction test

35. Why BETH Should Be a Positive Trial
Preselected population with VEGF-driven biology[1]
Preclinical (and apparent clinical) synergy between HER2 inhibitors and antiangiogenic therapy[2-4]
1. Konecny GE, et. al. Clin Cancer Res. 2004;10: Peagram M, et al. SABCS Abstract Blackwell KL, et al. SABCS. Abstract Slamon DJ, et al. SABCS Abstract 4114.

36. Why BEATRICE May Be a Negative Trial
VEGF does not appear to be the key angiogenic driver of relapse in triple-negative breast cancer
Alberta Breast Cancer Relapse Study
Mackey J, et. al. unpublished

37. University of Alberta Breast Study Case-Control Selection

38. Biomarker Selection

39. Triple-Negative Cohort: Proangiogenic Factor (Non-VEGF Related)

40. Collaborators Funding Raymond Lai, MD, PhD Cheryl Santos, MSc
Kathryn Graham, PhD
Roger Tsang, MD

41. Prediction on Predictive Assays for VEGF Pathway Inhibitors . . .
HER2 will be the marker of selective benefit from adjuvant antiangiogenic therapy in breast cancer
Multiplex solutions required for other cancers
Integrate tumor factors
Identify VEGF-dependent cancers
Integrate host factors
Constitutive upregulation of non–VEGFR-1 pathway or non-VEGF proangiogenic pathways

42. Take Home Messages
Antiangiogenic agents have modest population benefit in some metastatic settings
Progress will require better agents or more appropriately selected patient populations
No predictive biomarker has been validated
The most promising candidates include
HER2 positivity in breast cancer
Multiplexed approaches
Identifying VEGF-driven tumors
Integration with host factors