1. KRAS status and efficacy in the first- line treatment of patients with mCRC treated with FOLFOX with or without cetuximab: The OPUS experience Carsten Bokemeyer* I Bondarenko, J Hartmann, F De Braud, C Volovat, C Stroh, J Nippgen, I Celik, P Koralewski *Universitätsklinikum Eppendorf Hamburg, Germany

2. ASCO disclosure information Yes, I have honoraria to disclose Merck KGaA Yes, I have research funding to disclose Merck KGaA

3. Epidermal growth factor receptor (EGFR) and KRAS Cetuximab When KRAS gene is mutated, KRAS protein (p21 ras) is active regardless of EGFR activation KRAS gene mutations are an early event and are found in 40–45% of CRC patients KRAS mutations are generally associated with a poor prognosis

4. Retrospective studies supporting the correlation between KRAS mutations and lack of response to EGFR inhibitors in chemorefractory mCRC ReferenceTreatmentNo. of patients (% mutant) Objective response n (%) Wild-typeMutant A Lièvre et al, J Clin Oncol 2008 Cetuximab ± CT114 (32)34 (44)0 (0) S Benvenuti et al, Cancer Res 2007 Panitumumab or cetuximab or Cetuximab + CT 48 (33)10 (31)1 (6) W DeRoock et al, Ann Oncol 2008 Cetuximab or Cetuximab + irinotecan 113 (41)27 (41)0 (0) D Finocchiaro et al, ASCO Proceedings 2007 Cetuximab ± CT81 (40)13 (26)2 (6) F Di Fiore et al, Br J Cancer 2007 Cetuximab + CT59 (27)12 (28)0 (0) S Khambata-Ford et al, J Clin Oncol 2007 Cetuximab80 (38)5 (10)0 (0) RG Amado et al, J Clin Oncol 2008 Panitumumab208 (40)21 (17)0 (0)

5. First-line cetuximab + FOLFIRI: Correlation of KRAS status with efficacy First-line treatment: cetuximab then FOLFIRI + cetuximab (n=52) MonotherapyOverall assessment OutcomeWild-typeMutantWild-typeMutant RR (CR+PR), %27.6055.231.6 p=0.015p=0.144 Median PFS, months––9.45.6 HR=2.12 p=0.0475 Tabernero J et al, ASCO GI 2008

6. OPUS KRAS analysis: Objectives Objective A retrospective analysis investigated the impact on response rate and progression-free survival of the KRAS mutation status of tumors in the first-line treatment of metastatic CRC treated with FOLFOX ± cetuximab

7. OPUS: Study design Primary endpoint Overall confirmed response rate (as assessed by independent review) Secondary endpoints PFS time OS time Rate of curative surgery for metastases Safety Cetuximab + FOLFOX4 400 mg/m 2 initial IV infusion (day 1) then 250 mg/m 2 weekly + oxaliplatin 85 mg/m 2 + 5-FU/FA every 2 weeks FOLFOX4 Oxaliplatin 85 mg/m 2 + 5-FU/FA every 2 weeks EGFR-detectable mCRC Stratification by: ECOG PS 0/1, 2 R

8. OPUS: Efficacy results OutcomeFOLFOX (n=169) Cetuximab + FOLFOX (n=168) p-value RR, (%) ITT population 35.745.60.063 a RR, (%) ECOG PS 0/1 36.849.00.032 a Median PFS time, (months) 7.2 Hazard ratio for PFS0.930.62 Bokemeyer C et al, ECCO 2007 a Cochran-Mantel-Haenszel (CMH) test

9. Relating KRAS status to efficacy Methodology Efficacy analyses repeated to evaluate the influence of KRAS status on outcomes in OPUS patients Genomic DNA isolated from archived tumor material Paraffin-embedded, formalin-fixed tissue KRAS mutation status of codons 12/13 determined using quantitative PCR-based assay

10. KRAS evaluable population 337 subjects (ITT) 233 subjects: KRAS evaluable population 134 (58%) KRAS wild-type99 (42%) KRAS mutant Group A: 61 (46%) Group B 73 (54%) Group A 52 (53%) Group B 47 (47%) FOLFOXCetuximab + FOLFOX

11. Patient demographics at baseline KRAS evaluable population KRAS wild-type (n=134) % KRAS mutant (n=99) % Age <6563.462.6 Gender, male55.249.5 ECOG PS 0/188.890.9 Prior adjuvant therapy18.717.2 Involved disease sites  2 77.677.8 Liver-limited disease28.425.3

12. ITT and KRAS evaluable population: Comparability FOLFOX Cetuximab + FOLFOX Months KRAS population (n=233) HR=0.93; p=0.6609 mPFS Cetuximab + FOLFOX: 7.3 months mPFS FOLFOX: 7.2 months Months 0.0 0.5 1.0 0.4 0.3 0.2 0.1 0.6 0.7 0.8 0.9 8 0 2 4 6 10 12 ITT population (n=337) HR=0.93; p=0.6170 mPFS Cetuximab + FOLFOX: 7.2 months mPFS FOLFOX: 7.2 months 8 0 2 4 6 10 12 0.5 1.0 0.9 0.8 0.7 0.6 0.4 0.3 0.2 0.1 0.0 Progression-free survival estimate

13. Relating KRAS status to efficacy Primary endpoint: Response – KRAS wild-type FOLFOX (n=73) % Cetuximab + FOLFOX (n=61) % CR1.43.3 PR35.657.4 SD41.131.1 PD16.44.9 NE5.53.3 RR37.060.7 95% CI26.0–49.147.3–72.9 p=0.011 Odds ratio=2.544 (95% CI: 1.238–5.227) 0 10 20 30 40 50 60 70 Response rate (%) Cetuximab + FOLFOX FOLFOX 37 61

14. Relating KRAS status to efficacy Primary endpoint: Response – KRAS mutant FOLFOX 49 33 Cetuximab + FOLFOX FOLFOX (n=47) % Cetuximab + FOLFOX (n=52) % CR4.30 PR44.732.7 SD36.251.9 PD10.613.5 NE4.31.9 RR48.932.7 95% CI34.1–63.920.3–47.1 Response rate (%) 0 10 20 30 40 50 60 70 p=0.106 Odds ratio=0.507 (95% CI: 0.223–1.150)

15. Relating KRAS status to efficacy Secondary endpoint: PFS – KRAS wild-type 0.5 1.0 0.4 0.3 0.2 0.1 0.0 0.6 0.7 0.8 0.9 8 02 4 610 12 Months KRAS wild-type: HR=0.57; p=0.016 mPFS Cetuximab + FOLFOX: 7.7 months mPFS FOLFOX: 7.2 months FOLFOX Cetuximab + FOLFOX Progression-free survival estimate

16. Relating KRAS status to efficacy Secondary endpoint: PFS – KRAS mutant KRAS mutant HR=1.83; p=0.0192 mPFS Cetuximab + FOLFOX: 5.5 months mPFS FOLFOX: 8.6 months FOLFOX Cetuximab + FOLFOX 0.5 1.0 0.4 0.3 0.2 0.1 0.0 0.6 0.7 0.8 0.9 8 02 4 610 12 Months Progression-free survival estimate

17. Relating KRAS status to efficacy Progression-free survival Progression-free survival estimate Months Cetuximab + FOLFOX wild-type Cetuximab + FOLFOX mutant 0.5 1.0 0.4 0.3 0.2 0.1 0.0 0.6 0.7 0.8 0.9 802461012 Months FOLFOX wild-type FOLFOX mutant Cetuximab + FOLFOX HR=0.448; p=0.0009 mPFS Cet + FOLFOX wild-type (n=61): 5.5 months mPFS Cet + FOLFOX mutant (n=52): 7.7 months FOLFOX HR=1.404; p=0.1655 mPFS FOLFOX wild-type (n=73): 7.2 months mPFS FOLFOX mutant (n=47): 8.6 months

18. Relating KRAS status to efficacy Treatment exposure 5-FUOxaliplatinCetuximab FOLFOX alone Cetuximab + FOLFOX FOLFOX alone Cetuximab + FOLFOX KRAS wild-type (n=73/61) Median duration of treatment, weeks 24.024.124.024.125.1 Relative dose intensity ≥80%, % 7367827280 KRAS mutant (n=47/52) Median duration of treatment, weeks 24.020.024.020.518.0 Relative dose intensity ≥80%, % 7064797592

19. KRAS wild-typeKRAS mutant FOLFOX n=73 (%) Cetuximab + FOLFOX n=61 (%) FOLFOX n=47 (%) Cetuximab + FOLFOX n=52 (%) Any63.083.678.767.3 Neutropenia32.941.044.725.0 – Febrile neutropenia1.404.30 Diarrhea5.511.512.85.8 Peripheral sensory neuropathy 8.24.92.13.8 Acne-like rash a 014.8011.5 Infusion-related reactions 01.407.7 Relating KRAS status to efficacy Most common grade 3/4 AEs a There was no grade 4 acne-like rash

20. OPUS trial: Conclusions In patients with KRAS wild-type tumors, addition of cetuximab to FOLFOX resulted in a significant and relevant improvement in: –Response rate (61% vs. 37%; p=0.011) –Progression-free survival (HR=0.57; p=0.016) In patients with KRAS mutant tumors, the addition of cetuximab to FOLFOX had no apparent benefit The safety profiles of cetuximab and chemotherapy were generally comparable and consistent with their known safety profiles

21. Acknowledgements The authors would like to thank: –The patients –The investigators, co-investigators, and study teams at the 87 centers in 13 countries involved in this study –The study team at Merck KGaA, Darmstadt, Germany