1. Regina Elena National Cancer Institute
Treatment after anti-EGFR and anti-VEGF
Alain J. Gelibter
Regina Elena National Cancer Institute
Rome

2. Main Signaling and pathway
Shc
PI3-K
Raf
MEKK-1
MEK
MKK-7
JNK
ERK
Ras
mTOR
Grb2
AKT
Sos-1
The EGFR pathway is very complex pathway. Inhibitors to EGFR have proven antitumor activity in colorectal cancer.
Proliferation
Metastasis
Angiogenesis
Apoptosis Resistance 2

3. Why is MEK An Attractive Target ?
Convergence and divergence of the pathway
at MEK1/2
Multiple consequences of
pathway activation
Proliferation, survival,
differentiation and invasion 3

4. Selumetinib is a potent inhibitor of MEK Pathway in Cancer
GDP
GTP
RAS
RAS*
Raf
MEK1
MEK2
ERK1
ERK2
MEK Pathway
Growth
Factors
Extracellular
Cytoplasm
Constitutive activation of the pathway has been implicated in driving many cancers and in resistance to cancer
Mutant Ras & Raf proteins are key activators of the Ras-Raf-MEK-ERK pathway
B-Raf Mutations
Malignant melanomas (66%)
Papillary thyroid cancers (40%)
Colorectal cancer (8-10%)
Ras Mutations
Colon (40%)
Pancreatic cancers (90%)
NSCLC (20%)
AZD6244

5. Therapies for KRAS Mutated Colorectal Cancer That Is Resistant to EGFR Monoclonal Antibody Therapy
We observed that the MEK inhibitors are effective in inhibiting tumor cell growth on the D-MUT
cells harboring a K-ras mutation both in vitro and in vivo, in contrast to cetuximab. The MEK inhibitors reduced activities of the ATF2 transcription factors which were also not affected by cetuximab in K-ras mutated tumors. This study, based on the recent clinical observations related to cetuximab resistance (8–11, 22), is a pioneering study to investigate the responsiveness of an EGFR mAb to a K-ras mutation using isogenic colorectal cancer cell lines and their xenograft models.
Cancer Res 2011

6. AS703026 and AZD6244 inhibit tumor growth of
cetuximab-resistant tumor attributed by K-ras mutation
Cancer Res 2011

7. The MEK inhibitor selumetinib ([SEL], AZD6244, ARRY ) plus irinotecan (IRI) as second-line therapy for KRAS-mutated (KRASm) metastatic colorectal cancer (CRC).  
Patients
Treatment
KRASm or BRAFm Metastatic colorectal cancer
Progression during or after 1st-line bevacizumab/ oxaliplatin/ fluoropyrimidine
Measurable or nonmeasurable disease
Patients (Pts) were treated with IRI 180 mg/m2 iv q2w and SEL 50 or 75 mg po bid. Dose escalation was traditional 3+3 (50 mg bid SEL, then 75 mg bid).
In Part B/phase II, primary endpoint was PI-determined response rate (RR)
Howard S. Hochster, ASCO GI 2013:

8. The MEK inhibitor selumetinib ([SEL], AZD6244, ARRY ) plus irinotecan (IRI) as second-line therapy for KRAS-mutated (KRASm) metastatic colorectal cancer (CRC).  
Patients
IRI + AZD6244
(n = 31)
Male/Female
18/13
Median age (range)
54 (27-75)
Caucasian/other race
24/7
SEL 50 mg BID 3
SEL 75 mg BID 28
Patients
IRI + AZD6244
(n = 31)
Partial response (PR)
3 (10%)
Stable disease
16 (52%)
Median numbr of cycles
3.5
Median PFS (mts)
3.4
6 pts were on study for more than 6 (up to 22) months
Grade 3 AEs included (N): diarrhea 3, fatigue 2, neutropenia 2, and 1 each thrombocytopenia, enteritis, GI bleed, rash

9. MET Pathway and MET-Inhibiting Anticancer Agents

10. A Randomized, Phase 1/2 Trial of AMG 102 or AMG 479 in Combination With Panitumumab vs Panitumumab Alone in Patients With Wild‑Type KRAS Metastatic Colorectal Cancer (mCRC): Safety and Efficacy Results
 Eric Van Cutsem,1 Cathy Eng,2 Josep Tabernero,3 Elzbieta Nowara,4 Anna Świeboda-Sadlej,5
Niall C. Tebbutt,6 Edith P. Mitchell,7 Irina Davidenko,8 Lisa Chen,9 Dominic Smethurst10

11. Introduction
Panitumumab, a fully human monoclonal antibody against epidermal growth factor receptor (EGFR), has demonstrated efficacy in patients with wild-type KRAS mCRC in clinical trials1-4
Rilotumumab (AMG 102) and ganitumab (AMG 479) are investigational, fully human monoclonal antibodies against hepatocyte growth factor (HGF; ligand for c-Met receptor) and insulin‑like growth factor 1 receptor (IGF-1R), respectively
Preclinical studies indicate that there is complex interdependence between the HGF/c-Met and IGF-1R and EGFR pathways5-10
Combinations of agents that block these receptors are being investigated for their potential to generate additive/synergistic anticancer effects
1. Van Cutsem E, et al. J Clin Oncol. 2007;25:
2. Amado RG, et al. J Clin Oncol ;26:
3. Peeters M, et al. J Clin Oncol ;28:
4. Douillard JY, et al. J Clin Oncol ;28:
5. Lesko E, et al. Front Biosci ;13:
6. Hynes NE, et al. Nat Rev Cancer ;5:
7. Jo M, et al. J Biol Chem ;275:
8. Ahmad T, et al. J Biol Chem ;279:
9. Roudabush FL, et al. J Biol Chem ;275:
10. Swantek JL, et al. Endocrinology ;140:

12. Rilotumumab and Ganitumab Mechanisms of Action( )
Rilotumumab (AMG 102) targets HGF, inhibiting downstream c-Met signaling
Ganitumab (AMG 479) targets IGF-1R, inhibiting downstream signaling through PI3K/AKT and MAPK pathways

13. Study Schema
Amgen Trial ; ClinicalTrials.gov identifier NCT
Part 1 (Phase 1b)a
Part 2 (Phase 2)b
Part 3 (Phase 2)c R A N D O M I Z E
Panitumumab + Rilotumumab (AMG 102) Q2W R A N D O M I Z E
Rilotumumab (AMG 102) Q2W
Panitumumab + Rilotumumab
(AMG 102) Q2W
Panitumumab + Ganitumab (AMG 479) Q2W
Ganitumab (AMG 479) Q2W
Panitumumab + Placebo Q2Wd
aPanitumumab 6 mg/kg Q2W; rilotumumab (AMG 102) 10 mg/kg Q2W with dose de-escalation to 5 mg/kg as necessary; primary endpoint was incidence of dose-limiting toxicities
bPanitumumab 6 mg/kg Q2W; rilotumumab (AMG 102) dose based on phase 1b; ganitumab (AMG 479) 12 mg/kg Q2W; primary endpoint was ORR
cRilotumumab 10 mg/kg Q2W; ganitumab (AMG 479) 12 mg/kg Q2W; primary endpoint was ORR
dPatients in the placebo arm of Part 2 with progressive disease or intolerance to treatment were eligible to participate in Part 3
DLT, dose-limiting toxicity; ORR, objective response rate; Q2W, every 2 weeks
Tumor assessments were performed by the investigator using Response Evaluation Criteria in Solid Tumors (RECIST) v1.0

14. Study Objectives Primary Objectives (Part 1 and Part 2)
Part 1: To identify a tolerable dose of rilotumumab (AMG 102) in combination with panitumumab based on the incidence and nature of dose-limiting toxicities (DLTs)
Part 2: To evaluate the efficacy as measured by the objective response rate (ORR) of rilotumumab (AMG 102) + panitumumab and ganitumab (AMG 479) + panitumumab vs panitumumab + placebo
Other Key Objectives (Part 2)
Efficacy including progression-free survival (PFS) and overall survival (OS)
Safety
Pharmacokinetic analysis
Biomarker analysis

15. Key Eligibility Criteria
Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
Histologically or cytologically confirmed wild-type KRAS mCRC by local or central testing
Progression during or following prior treatment with irinotecan- and/or oxaliplatin-based chemotherapy for mCRC
No prior treatment with EGFR, c-Met, or IGF-1R inhibitors

16. Part 2: Patient Demographics and Disease Characteristics at Baseline
Panitumumab + Placebo (n = 48)
Panitumumab + Rilotumumab (AMG 102) (n = 48)
Panitumumab + Ganitumab (AMG 479) (n = 46)
Men - n (%)
28 (58)
29 (60)
25 (54)
Age - mean years (range)
55.0 (19-75)
62.1 (45-78)
62.0 (33-81)
ECOG status - n (%)
15 (31) 33 (69)
24 (50) 23 (48)a
18 (39) 28 (61)
Metastatic sites - n (%) Liver only Liver + other sites
5 (10) 27 (56)
5 (10) 32 (67)
4 (9) 29 (63)
Prior therapies for mCRC - n (%) First-line therapy Second-line therapy Third-line therapy and later
46 (96)b 31 (65) 14 (29)
48 (100) 33 (69) 16 (33)
46 (100) 26 (57) 12 (26)
Prior chemotherapies for mCRC - n (%) Oxaliplatin Irinotecan Oxaliplatin and irinotecan
39 (81) 30 (63) 23 (48)
42 (88) 32 (67) 26 (54)
40 (87) 26 (57) 20 (44) .
aOne patient with ECOG performance score of 2 was enrolled in error; data from this patient were included in all efficacy and safety analyses
bTwo patients had not received first-line therapy for mCRC; both patients had received oxaliplatin-based chemotherapy for non-metastatic CRC in the adjuvant setting and progressed on therapy before entering the study

17. Part 2: Primary Endpoint Overall Response Rate
Panitumumab + Placebo (n = 48)
Panitumumab + Rilotumumab (AMG 102) (n = 48)
Panitumumab + Ganitumab (AMG 479) (n = 46)
Objective Response - n (%)
Complete Response (CR)
Partial Response (PR)
Stable Disease (SD)
Progressive Disease (PD)
Unevaluable/Not done
10 (21)
0 (0)
17 (35)
16 (33)
5 (10)
15 (31)
19 (40)
11 (23)
3 (6)
10 (22)
18 (39)
15 (33)
Disease control ratea - % (95% CI)
56 (41-71)
71 (56-83)
61 (45-75)
Duration of response - median months (95% CI)
3.7 (3.6-NE)
5.1 ( )
3.7 ( )
Posterior probability of Odds Ratio > 1b
0.93
0.63 1
aDisease control rate = CR + PR + SD
bOR is calculated based on ORR; an OR > 1 favors the combination arm over panitumumab alone
NE, not estimable
Responses were required to be confirmed at least 4 weeks after response criteria were first met

18. Part 2: Progression-Free Survival
Panitumumab ± Rilotumumab (AMG 102)
(AMG 102)
(AMG 102)
Panitumumab ± Ganitumab (AMG 479)
(AMG 479)
(AMG 479)

19. Conclusions
This is the first study to show promising evidence of efficacy by an HGF (c-Met pathway) inhibitor (rilotumumab [AMG 102]) when combined with panitumumab in patients with mCRC
The activity as assessed by ORR for patients receiving rilotumumab (AMG 102) plus panitumumab is promising (per prospectively specified Bayesian criterion)
Efficacy of ganitumab (AMG 479) plus panitumumab combination therapy as determined by ORR was indeterminate
The safety profiles of the drug combinations were generally similar to that of panitumumab alone with some exceptions, including a higher rate of grade 3/4 rash with rilotumumab and of hypomagnesemia with ganitumab

20. ONARTUZUMAB
Onartuzumab is a monoclonal antibody designed to bind to MET and inhibit HGF/SF binding. Traditional bivalent antibodies to MET potentially activate, rather than inhibit, MET signaling by inducing MET dimerization. In contrast, the monovalent design of onartuzumab inhibits HGF/SF binding without inducing MET dimerization.
Blockade of MET activation inhibits its downstream pathways, preventing cancer cell growth, survival, and metastasis
Onartuzumab binds to the Sema domain of MET, an extracellular region essential for binding its ligand, HGF/SF
Inhibits HGF/SF from binding to MET, thereby blocking ligand-induced MET dimerization and activation of the intracellular kinase domain

22. PD and efficacy analysis of the B-RAF inhibitor dabrafenib (GSK436) in combination with the MEK inhibnitor TRAMETINIB (GSK 212) in pts with BRAF V600E mutant CRC
ASCO 2013

23. Overview of BRAF-mutant CRC
BRAF V600 mutations occur in 5-10% of CRC
Occur in K-ras wild type population
Worse prognosis than KRAS mutant or KRAS-BRAF wild type
May predict lack of response to anti-EGFR treatment
Distinct undrlying biology of BRAF-mutant CRC
Novel therapeutic strategies for BRAF-mutant CRC are critically needed.
1. Van Cutsem E, et al. ASCO Abstract Tol J, et al. NEJM. 2009;361: Di Nicolantonio F, et al. J Clin Oncol. 2008;26: Laurent-Puig P, et al. J Clin Oncol. 2009;27: Loupakis F, et al. Br J Cancer. 2009;101: Van Cutsem E, et al. J Clin Oncol. 2011;29: Bokemeyer C, et al. ASCO Abstract 3506.

24. BRAF Mutations in First-Line Setting
CRYSTAL and OPUS combined analysis
Patients with wild-type KRAS/mutated BRAF
Worse outcomes vs wild-type KRAS/wild-type BRAF
Still experienced non-significant improvements (small N)
Outcome
Wild-type KRAS/ Mutated BRAF
Wild-type KRAS/ Wild-type BRAF
Cetuximab + CT
CT Only
P Value
Median PFS, mos
7.1
3.7
.267
10.9
7.7
< .001
Median OS, mos
14.1
9.9
.079
24.8
21.1
.041
Median ORR, %
21.9
13.2
.4606
60.7
40.9
< .0001
CT, chemotherapy; ORR, overall response rate; OS, overall survival; PFS, progression-free survival.
Bokemeyer C, et al. ASCO Abstract 3506. 24

25. B-RAF mutant melanoma Response rate 60-80%
B-RAF mutation: Melanoma vs CRC
B-RAF mutant melanoma Response rate 60-80%
B-RAF mutant CRC Response rate less than 10%
Same target, same drug, different disease…….different response!!!
Flaherty et al NEJM Kopetz et al ASCO 2010

27. PD and efficacy analysis of the B-RAF inhibitor dabrafenib (GSK436) in combination with the MEK inhibnitor TRAMETINIB (GSK 212) in pts with BRAF V600E mutant CRC
Dabrafenib (150mg BID)
Trametinib (2mg QD)

28. PD and efficacy analysis of the B-RAF inhibitor dabrafenib (GSK436) in combination with the MEK inhibnitor TRAMETINIB (GSK 212) in pts with BRAF V600E mutant CRC
Patients
(n = 40)
Gender:Female
32 (80%)
ECOG 1
18 (45%)
B-RAF V600E Mutation
40 (100%)
Disease sites at screening n (%)
<3 sites
> 3 sites
19 (48%)
Patients
(n = 40)
Number of lines of prior systemic anticancer therapy
2 (5%) 1
5 (13%) 2
12 (30%)
> 3
21 (53%)
Prior EGFR inhibitor
18 (45%)

29. PD and efficacy analysis of the B-RAF inhibitor dabrafenib (GSK436) in combination with the MEK inhibnitor TRAMETINIB (GSK 212) in pts with BRAF V600E mutant CRC
1 (3%) achieved a complete response (confirmed, on study >12m),
3 (9%) achieved a partial response and 18 (53%) had stable disease (SD).

30. Efficacy Median PFS was 3.5 mo (95% CI: 1.8-4.9);
7 pts (24%) remained on study for ≥6 cycles
with 9 pts still on study.

31. 2 pts discontinued due to AEs.
Toxicity
AE any grade
Grade3-4
Any grade
(n = 40)
Pyrexia
10%
67%
Nausea 5%
56%
Fatigue 8%
53%
Chills 3%
47%
Vomiting
39%
Headache
31%
Anemia
20%
28%
Diarrhea
25%
2 pts discontinued due to AEs.

32. pERK reduction
Decreased pERK staining vs pre-dose samples was seen in all post-dose samples leading to absolute (49% ±29%) and relative (69% ±28%, normalized to total ERK) reduction in pERK.

34. Study conclusions
Treatment with D and T combine safetely in B-RAF mutant CRC patients
Clinical activity is seen in a subset of patients
About 1/3 of PTS with at least a minor response
25% of PTS with PFS > 6 mts
Biomarker analyses
Reduction in pERK observed in all patients.
PIK3CA mutations do not preclude clinical activity
MSI and low EGFR may be associated with better outcomes

35. Next step for BRAF/MEK Inhibition?

36. BRAF/MEK/EGFR Inhibitor Combination Study in Colorectal Cancer
An open-label, three-part Phase 1/2 study to investigate the safety, pharmacokinetics, pharmacodynamics and clinical activity of trametinib (GSK ) and dabrafenib (GSK ) when administered in combination with the anti-EGFR antibody panitumumab in subjects with BRAF-mutation V600E or V600K positive colorectal cancer (CRC).

37. The phosphatidylinositol 3-kinase (PI3K) signaling cascade
Activation
Inhibition
Inhibition of PI3K signaling can diminish cell proliferation, and in some circumstances, promote cell death

38. Activation of PI3K signaling in Cancer
PI3K signaling is activated in human cancers via several different mechanisms.
Increased PI3K signaling is often due to direct mutational activation or amplification of genes encoding key components of the PI3K pathway such as PIK3CA and AKT1, or loss of PTEN
Philip AJ Cancer Research

39. Genetic alterations of the PI3K Signaling Pathway in Cancer

40. PI3K inhibitors in Clinical trials.

41. mTOR inhibitors

42. A Phase II Trial of Bevacizumab plus Everolimus for Patients with Refractory Metastatic Colorectal Cancer
Altomare The Oncologist 2011

43. A Phase II Trial of Bevacizumab plus Everolimus for Patients with Refractory Metastatic Colorectal Cancer
8 patients had minor responses (16%) and an additional 15patients (30%) had stable disease (SD). No CR, not PR.
PFS was 2.3 months;
Altomare The Oncologist 2011

44. A Phase II Trial of Bevacizumab plus Everolimus for Patients with Refractory Metastatic Colorectal Cancer
Conclusions
Bevacizumab plus everolimus is generally tolerable but may have risks related to mucosal damage and/or wound healing.
Bevacizumab plus everolimus appears to have modest activity in refractory mCRC in patients.

45. Multicenter Phase II Study of Tivozanib (AV-951) and Everolimus (RAD001) for Patients With Refractory, Metastatic Colorectal Cancer
Methods
The phase Ib study followed a 3+3 dose-escalation design with three dose levels.
The primary objective in the follow-on phase II study was improvement in 2-month progression-free survival (PFS) from 30% (historical benchmark) to 50% in patients with refractory, metastatic colorectal cancer.
Wolpin BM The Oncologist 2013

46. Multicenter Phase II Study of Tivozanib (AV-951) and Everolimus (RAD001) for Patients With Refractory, Metastatic Colorectal Cancer
Wolpin BM The Oncologist 2013

47. Multicenter Phase II Study of Tivozanib (AV-951) and Everolimus (RAD001) for Patients With Refractory, Metastatic Colorectal Cancer
By independent radiologic review, 50% of 40 patients with refractory metastatic colorectal cancer had stable disease as their best response.
Nearly 20% of patients remained on study treatment for 6 months.
The disease control rate (DCR) of 50% and median PFS of 3.0 months compare favorably to trials in similar patient populations with refractory colorectal cancer, Including a 99-patient phase II trial of everolimus alone (DCR: 25.3%; median PFS: 1.7 months), a 50-patient phase II trial of bevacizumab and everolimus (DCR: 46%; median PFS: 2.3 months).

48. Multicenter Phase II Study of Tivozanib (AV-951) and Everolimus (RAD001) for Patients With Refractory, Metastatic Colorectal Cancer
The phase II study met its primary endpoint, with 50% of patients achieving PFS at 2 months.
Outcomes did not appear to differ by tumor KRAS mutation status.
In contrast, better outcomes in patients who developed grade 1 hypertension while receiving tivozanib and everolimus. (predictive biomarker for antiangiogenenic agents in colorectal cancer?).
Thus, modest efficacy was suggested for this drug combination in a patient population that greatly needs novel treatment programs.

49. PI3K pathway: Conclusions
It remains unclear whether single-agent PI3K pathway inhibitors will promote
dramatic responses (comparable to gefitinib in EGFR-mutant lung Cancers even in sensitive cancers.
Most models of cancers that are sensitive to single-agent PI3K pathway inhibitors have demonstrated tumor stasis in vivo rather than frank tumor regressions.
Data suggest that cancers with KRAS mutations may be fairly resistant to PI3K pathway inhibitors.
Consequently, necessary to combine PI3K pathway inhibitors with other agents

50. Conclusions and Future directions
Predictive biomarkers have the potential to improve selection of the right drug for the right patient, but, aside from K-RAS (n-RAS), there has been little progress in incorporating these into clinical practice in CRC.
Identification of Biomarkers strongly needed
Multitarget treatment are needed after preclinical and pharmacodynamic studies