1. Targeting the MAPK pathway
Josep Tabernero, MD PhD
Medical Oncology Department
Vall d’Hebron University Hospital &
Vall d’Hebron Institute of Oncology
Barcelona
Great Debates & Updates in GI Malignancies
NY, March 28th, 2014

2. DISCLOSURES
Speaker’s Bureau
Amgen
Merck Kga
Novartis
Sanofi
Roche

3. Advances in the treatment of mCRC
5-FU
Oral fluoropyrimidines
Irinotecan
Oxaliplatin
2000
More options
RR ≈ 50%
mTTP 8−9 months mOS months
Optimal regimens
Sequencing
Treatment duration
1995
One option
RR 50%+
mTTP 9+ months mOS 22+ months
Cure
5-FU Oral fluoropyrimidines
Irinotecan
Oxaliplatin
Cetuximab, Panitumumab
Bevacizumab, Aflibercept
Regorafenib
2014
Many options
Optimal regimens
Correct sequencing & dosing
Cost
Biomarkers
5-FU
First-line efficacy
RR 20%
mTTP 5−6 months mOS 10−12 months
Issues
Low efficacy

4. Targeting the EGFR pathway in CRC
TGF-α
Amphiregulin
Epiregulin
Anti-EGFR MoAbs
(RAS inh.)
RAF inh.
MEK inh.
ERK inh.
Inhibitors
EGFR expression 27–95%
KRAS mutation 45–50%
NRAS mutation 5-8%
KRAS
EGFR
Sos
Grb2
BRAF
BRAF mutation 5-10%
EGFR mutation 1-2%
MEK
MAPK
TGF = transforming growth factor
Adapted from Roberts and Der. Oncogene 2007 4

5. CO.17: phase III trial
Failed or intolerant to all recommended therapies
REGISTER
RANDOMI ZE
Cetuximab* + BSC
EGFR testing by IHC
Disease progression or
Unacceptable toxicity
BSC alone
1:1
Stratification:
Centre
ECOG PS (0 or 1 vs. 2)
Jonker et al, NEJM 2007;357:2040-8

6. NCIC CTG CO.17: mCRC Cetuximab vs BSC
CO.17: phase III trial
NCIC CTG CO.17: mCRC Cetuximab vs BSC
HR OS: ITT 0.7  KRAS wt 0.55
1Jonker, DJ et al. NEJM;357:2040-8,2007
2Karapetis, CS. et al. NEJM;359: ,2008

7. CRYSTAL: Study design Cetuximab + FOLFIRI R FOLFIRI
Cetuximab IV 400 mg/m2 on day 1,
then 250 mg/m2 weekly + irinotecan (180 mg/m2)
+ 5-FU (400 mg/m2 bolus +
2400 mg/m2 as 46-hr
continuous infusion)
+ FA every 2 weeks
EGFR-expressing
mCRC R
Stratification by:
Regions
ECOG PS
Populations:
Randomized patients (n=1217)
Safety population (n=1202)
ITT population (n=1198)
FOLFIRI
Irinotecan (180 mg/m2)
+ 5-FU 400 mg/m2 bolus +
2400 mg/m2 as 46-h
continuous infusion)
+ FA every 2 weeks
Van Cutsem E, et al. NEJM 2009

8. CRYSTAL study – final results
ITT
KRAS wild-type
KRAS mutant
FOLFIRI
FOLFIRI + cetuximab
(n=599)
(n=350)
(n=316)
(n=87)
(n=105)
RR (%) 39 47 40 57 36 31
p=0.0038a
p<0.001a
p=0.35a
mPFS (months)
8.0
8.9
8.4
9.9
7.7
7.4
Hazard ratio
0.85
0.7
1.17
p=0.048
p=0.0012
p=0.26
mOS (months)
18.6
19.9
20.0
23.5
16.7
16.2
0.93
0.8
1.04
p=0.30
p=0.0093
p=0.75
aCochran–Mantel–Haenszel test
Van Cutsem E, et al. J Clin Oncol 2011; 29:2011-9 8

9. CRYSTAL study – final results by KRAS/BRAF status
KRAS/BRAF wild-type
KRAS wild-type / BRAF mutant
FOLFIRI
CETUXIMAB + FOLFIRI
Cetuximab + FOLFIRI
(n=289)
(n=277)
(n=33)
(n=26)
RR (%) 43 61 15
8.0
p<0.001a
p=1.08a
mPFS (months)
8.8
10.9
5.6
7.4
Hazard ratio
0.67
1.17
p=0.0013
p=0.87
mOS (months)
21.6
25.1
10.3
14.1
0.83
0.91
p=0.0547
p=0.74
aCochran–Mantel–Haenszel test
Van Cutsem E, et al. J Clin Oncol 2011; 29:2011-9 9

10. PRIME trial FOLFOX4  panitumumab in 1st-line treatment of mCRC
Design amended to focus on prospective hypothesis testing in the KRAS WT† stratum
Study endpoints: PFS (1º); OS, ORR, safety, HRQoL
L o n g t e r m f
o l l o w u p
E n d o f t r e a t m e n t
Panitumumab 6 mg/kg (Q2W) +
FOLFOX4 (Q2W)
mCRC
(n = 1183) R
1:1
Disease assessment every 8 weeks
†WT in codons 12 and 13.
HRQoL, Health-related quality of life; mCRC, metastatic colorectal cancer; OS, overall survival; PFS, progression-free survival; ORR, objective response rate.
Douillard JY, et al. J Clin Oncol 2010;28:4697–705; protocol ID: ; ClinicalTrials.gov identifier: NCT

11. KRAS, NRAS and BRAF mutation hotspots in the PRIME study
EXON 2
EXON 3
EXON 4
EXON 1 12 13 61
117
146
BRAF
EXON 15
EXON 16…
EXON 1…
600
40% 4% 6% 3% 1% 59 8%
All RAS mutation testing might identify an additional 15–20% mutants

12. PRIME RAS/RAF OS analysis*
Overall survival
Original WT KRAS exon 2 testing
WT RAS 2 4 6 8 10 12 14 16 18 24 20 22 36 26 28 30 32 34
Proportion alive (%)
100 90 70 60 80 50 40
HR = 0.83 (95% CI, 0.67–1.02)
P = 0.072
Months 2 4 6 8 10 12 14 16 18 24 20 22 36 26 28 30 32 34
Proportion alive (%)
100 90 70 60 80 50 40
Months
HR = 0.78 (95% CI, 0.62–0.99)
P = 0.043
Events n (%)
Median (95% CI) months
Panitumumab + FOLFOX4 (n = 325)
165 (51)
23.9 (20.3–28.3)
FOLFOX4 (n = 331)
190 (57)
19.7 (17.6–22.6)
Events n (%)
Median (95% CI) months
Panitumumab + FOLFOX4 (n = 259)
128 (49)
26.0 (21.7–30.4)
FOLFOX4 (n = 253)
148 (58)
20.2 (17.7–23.1)
*Predefined retrospective analysis; 7 patients harbouring Codon 59 mutations were not excluded from this analysis.
1. Douillard JY, et al. J Clin Oncol 2010;28:4697–705; 2. Douillard JY et al New Engl J Medicine Sept

13. Potential biomarkers in mCRC for EGFR inhibitors
On/Off marker
Threshold marker
KRAS mut
BRAF mut
NRAS mut
PIK3CA mut
TP53 mut
PTEN mut
EGFR mut
EGF & EGFR polymorphisms
COX-2
PTEN
EGF
Epiregulin
Amphiregulin
EGFR expression
DUSPs
Mitogen-activated protein kinase phosphatase-1 (MKP-1)
Signatures
Genomic/Proteomic

14. BRAF mutant CRC Small population: 8-10% early stage 4-5% late stage
BRAF V600E mutations as a biomarker?
very poor prognosis in late stage (mCRC)
no clear prognostic effect in early stage
predictive: negative predictive effect for anti-EGFR MoAbs in some studies:
Cetuximab: refractory (European cons.)1,2 & first-line setting (CRYSTAL study)3
Panitumumab: 2nd line setting (PICCOLO study)4
No change in the label by any regulatory authority
1 Di Nicolantonio F, J Clin Oncol 2018; 2 De Roock et al. Lancet Oncol 2010; 3Van Cutsem et al, J Clin Oncol 2011; 4Seymour MT et al, Proc ASCO 2011

15. Vemurafenib in BRAF V600E mutant mCRC
(RECIST cutoff for PR, 30%)
n=19 Evaluable Patients
1 PR and 4 MRs (≥10% shrinkage)
Interim - 12/31/09
Outstanding activity of vemurafenib in metastatic melanoma with BRAF V600E mutations
Preclinical activity shown in limited CRC BRAF V600 mutated cells1
Marginal activity in metastatic CRC with BRAF V600E mutations2
1Yang H et al. Clin Cancer Res 2011; 2Kopetz S et al, Proc ASCO 2010

16. BRAF inhibitors + EGFR inhibitors have in vivo activity in BRAFV600E mutant CRC xenografts
Corcoran RB et al, Cancer Discov 2012;2:227-35
Prahallad A et al, Nature 2012;483:100-3

17. New studies in the BRAFV600E mutant CRC population
As examples of clinical trials evaluating the combination of BRAFV600E inhibitors plus anti-EGFR inhibitors in the BRAF mutant population in CRC:
NCT : Vemurafenib + Cetuximab (BASKET) – Phase Ib
NCT : BRAF/MEK Inhibitors (dabrafenib + trametinib) + Panitumumab – Phase Ib RP2
NCT : LGX818 and Cetuximab or LGX818, BYL719, and Cetuximab – Phase IbRP2

19. Connolly K et al. Curr Oncol 2014

20. RAS mutant CRC Big population: 50% KRAS mutations 5-8% NRAS mutations
RAS mutations as a biomarker?
no clear prognostic effect in early/late stage
predictive: negative predictive effect for anti-EGFR MoAbs:
KRAS for Cetuximab & Panitumumab: 1st, 2nd and late stage
NRAS for Panitumumab: 1st & 2nd line
NRAS for Cetuximab: 1st line
1 Di Nicolantonio F, J Clin Oncol 2018; 2 De Roock et al. Lancet Oncol 2010; 3Van Cutsem et al, J Clin Oncol 2011; 4Seymour MT et al, Proc ASCO 2011
4Douillard JY et al, N Engl J Med 2013; 5Stintzing S et al. Proc ECCO 2013

21. MEK inhibition leads to PI3K/AKT activation by relieving a negative feedback on ERBB receptors
1Turke A et al. Cancer Research 2012

22. New studies in the RAS mutant CRC population
MEK inhibitors + EGFR inhibitors in RAS mutant CRC:
CMEK162X2116: A phase Ib/II study of MEK162 in combination with panitumumab in patients with metastatic KRAS-mutant or -WT CRC
MEK inhibitors + EGFR/HER3 inhibitors in RAS mutant CRC:
GO29030: A phase Ib study of MEHD7945A in combination with cobimetinib (GDC-0973) in patients with metastatic KRAS-mutant cancers
MEK inhibitors + IGF1R inhibitors in RAS mutant CRC:
CMEK162X2111: A phase Ib study of AMG479 (anti IGF-1R) in combination with MEK162 in patients with solid tumors

23. Unsupervised molecular subtyping of CRC - Microarray

24. PIs: Justin Guinney
Rodrigo Dienstmann

25. Summary
Target discovery has resulted in numerous novel drugs in clinical development
Different CRC subtypes: genomic signatures
Tumor heterogeneity and clonal selection/evolution
Signal transduction inhibition does not guarantee tumor response (BRAF V600 E mutant):
Target presence and dependence
Redundancy
Cross-talk
Need for molecular profile and selection
Combinations: mechanistic interactions, rationale-based
Need to sequentially evaluate tumor cells (tumor tissue, CTCs, cfDNA, …)