1. P.A. Tang 1, S. J. Cohen 1, G. Bjarnason 1, C. Kollmannsberger 1, K. Virik 1, M. J. MacKenzie 1, J. Brown 1, L. Wang 1, A. Chen 2, M. J. Moore 1 1 Princess Margaret Phase II Consortium, Toronto, Canada 2 National Cancer Institute, Rockville, MD Phase II trial of aflibercept in previously treated patients with metastatic colorectal cancer: A PMH Phase II Consortium Trial Supported by NCI contract: NO1-CM-62203

2. Background VEGF expression is associated with aggressive tumor biology and poor prognosis in metastatic colorectal cancer (MCRC) Addition of bevacizumab to chemotherapy improves response rates and extends survival Aflibercept (VEGF Trap, AVE0005) Recombinant humanized fusion protein containing epitopes from VEGFR1, VEGFR2, and the Fc portion of IgG1 Potential therapeutic advantages – –Greater VEGF-A binding affinity than humanized monoclonal Ab – –Also targets VEGF-B, placental growth factor 1 and 2 – –Longer circulating half-life – –Consists of human protein sequences (less potential for immune reactions) Anti-tumor efficacy has been demonstrated in preclinical xenograft models, including human colon cancer Given the activity of bevacizumab in MCRC, and the higher binding affinity of aflibercept to VEGF-A, a phase II trial of aflibercept was conducted in patients (pts) with MCRC who had progressed after receiving at least 1 line of chemotherapy for metastatic disease.

3. Primary objective – –Determine the response rate (RR) and incidence of disease stabilization (as measured by 4 month progression free survival)

4. Methods Patients with MCRC progressed after > 1 line of chemo for metastatic disease Stage I: Enroll 22 pts in each cohort Aflibercept 4mg/kg IV q 2 wks 2 wks = 1 cycle Assess response every 4 cycles Bevacizumab NaivePrior Bevacizumab Key Eligibility Criteria Measurable disease (RECIST) Adequate hematological, renal, hepatic function Prior treatment with EGFR inhibitors was permitted No anti-angiogenic therapies other than bevacizumab

5. Statistical Considerations Stage I: 22 pts Bevacizumab Naïve Prior Bevacizumab Proceed to Stage II + accrue 18 more pts if > 2 pts PR/CR or 4 mo PFS > 10 pts (45%) 2 pts PR/CR or 4 mo PFS > 6 pts (27%) Active treatment if > 4 pts PR/CR or 4 mo PFS > 20 pts (50%) 4 pts PR/CR or 4 mo PFS > 13 pts (32.5%) α = 0.05; β = 0.20

6. Results Between November 2006 and April 2008, 64 pts were enrolled from 8 North American centres. Received a median of 4 cycles, range (1-16). Bevacizumab-naïve cohort was closed after stage I, median follow up 2 mo, all pts have come off treatment. Prior Bevacizumab cohort has completed stage II accrual. Median follow up 3 mo

7. Baseline Characteristics Characteristics Bevacizumab Naïve n=24 Prior Bevacizumab n=40 Median Age (Range) 60 (42-80) 59 (39-71) Female: Male 9:1514:26 ECOG 0:1:2 6:17:120:17:3 Previous radiation 1113 # Prior Regimens Metastatic Disease 1:2:3:4+ 6:11:5:27:9:10:14

8. Response Response Bevacizumab Naïve n = 24 Prior Bevacizumab n = 40 # pts % % Partial response 001*3 Stable Disease Stable Disease 16 wks 10742291774318 Inevaluable41725 Too Early 00923 * Confirmed response (central radiology review)

9. Waterfall plot demonstrating maximum change in tumor size Nadir target tumors compared with baseline -0.4 -0.2 0.0 0.2 0.4 Naïve Treated

10. Kaplan Meier Curve of Progression free survival – Bevacizumab Naive

11. Kaplan Meier Curve of Progression-free survival – Prior Bevacizumab

12. Progression free survival Progression free survival (95%CI) Bevacizumab Naïve n = 24 Prior Bevacizumab n = 40 4 month PFS rate 31 % (16 - 62) 29% (14 - 58) Median PFS 2.4 mo (1.7-8.5) 3.4 mo (1.9- NR)

13. Adverse events experienced by > 10% of patients NCI CTC AE Adverse Event All Grades Grade 3/4 # patients % % Fatigue4378.235.5 Hypertension3156.459.1 Proteinuria2647.359.1 Headache2443.635.5 Dysphonia1730.900 Anorexia1323.600 Joint Pain 1018.200 Nausea814.500 Epistaxis814.500 Lymphopenia712.700 Weight loss 610.900 Myalgia610.900 Low serum albumin 610.900 Abdominal pain 610.911.8 Discontinuation of treatment for toxicity: Bevacizumab naïve: 3 pts; Prior bevacizumab: 7 pts 1 death on study due to progression

14. Conclusions Aflibercept is well tolerated in pretreated pts with MCRC Single agent activity has been observed in the Prior Bevacizumab cohort, primarily in the form of stable disease. Future studies should explore aflibercept in combination with chemotherapy in MCRC.