ASCO Annual Meeting 2012 PHASE II STUDY OF PANITUMUMAB (P) IN COMBINATION WITH FOLFOXIRI AS FIRST-LINE TREATMENT OF METASTATIC COLORECTAL CANCER (MCRC): HIGH ACTIVITY IN MOLECULARLY SELECTED PATIENTS (PTS). Sara Lonardi 1, Lorenzo Fornaro 2, Francesca Bergamo 1, Marta Schirripa 2, Giuseppe Aprile 3, Manfredi Morvillo 2, Gianluca Masi 2, Fotios Loupakis 2, Lorenzo Calvetti 1, Chiara Cremolini 2, Lisa Salvatore 2, Alberto Zaniboni 4, Vittorina Zagonel 1, Alfredo Falcone 2 ; 1 Oncologia Medica 1, Istituto Oncologico Veneto - IRCCS, Padova, Italy; 2 Oncologia Medica 2, Azienda Ospedaliero-Universitaria Pisana, Istituto Toscano Tumori, Pisa, Italy; 3 Oncologia Medica, Azienda Ospedaliero-Universitaria, Udine, Italy; 4 Oncologia Medica, Casa di Cura Poliambulanza, Brescia, Italy

 The combination of anti-EGFR monoclonal antibodies with doublet cemotherapy is an effective strategy in the first-line treatment of mCRC. Van Cutsem E, N Eng J Med 2009 Douillard JY, J Clin Oncol 2010  The triple drug combination FOLFOXIRI demonstrated increased activity and efficacy over FOLFIRI. Falcone A, J Clin Oncol 2007 Masi G, J Natl Cancer Inst 2011  KRAS codon mutations predict resistance to Panitumumab. Amado RG, J Clin Oncol 2008  Mutations in other KRAS codons (such as codon 61) and other members of the RAS family (mainly HRAS and NRAS) may predict resistance to anti-EGFR agents. De Roock W, Lancet Oncol 2010  BRAF V600E mutation may predict resistance to anti-EGFR agents. Di Nicolantonio F, J Clin Oncol 2008 Loupakis F, Br J Cancer 2009 RationaleRationale

Study Design INDUCTION TX up to 12 cycles or PD or unacceptable toxicity or patient’s refusal MAINTENANCE TX until PD or intolerable toxicity or patient’s refusal *≈70 pts needed to be screened  incidence of RAS and BRAF mutations ≈50% FOLFOXIRI + P-mab P-mab +/- 5FU 35 mCRC pts wild-type for: KRAS codon KRAS codon BRAF codon 600 BRAF codon 600 HRAS-NRAS codon HRAS-NRAS codon

Induction Treatment Schedule (after amendment) 5FU flat continuous infusion 2400 mg/sqm 5FU flat continuous infusion 2400 mg/sqm L-LV 200 mg/sqm L-LV Oxaliplatin 85 mg/sqm Oxaliplatin 2 hours Repeated every 2 weeks Irinotecan 150 mg/sqm Irinotecan 48 hours Day 1 Day 2 & Day 3 1 hour P-mab 6 mg/Kg P-mab 1 hour 5FU DOSE AMENDED AFTER 2 SAEs OCCURRED AMONG THE FIRST 3 PTS ENROLLED

Histologically confirmed colorectal adenocarcinoma Availability of formalin-fixed paraffin embedded tumor block from primary or metastasis RAS and BRAF wild-type status of primary colorectal cancer or related metastasis Unresectable and measurable metastatic disease (RECIST criteria) Adjuvant chemotherapy ended more than 12 months before relapse Age ≥ 18 years and ≤ 75 years ECOG PS ≤ 2 if aged < 71 years and ECOG PS = 0 if aged years Adequate hematological, liver and kidney function Prior palliative chemotherapy Prior treatment with EGFR inhibitors Symptomatic peripheral neuropathy ≥ 2 grade according to NCIC-CTG criteria Main Enrollment Criteria

Study Objective and End-points The objective of the trial is to investigate the activity of FOLFOXIRI + panitumumab as first-line treatment in KRAS, NRAS, HRAS and BRAF wild-type mCRC patients. PRIMARY END-POINT:  PRIMARY END-POINT: Response Rate SECONDARY  SECONDARY END-POINTS: Progression Free Survival Secondary R0 surgery of metastases Overall survival Safety profile Analyses of potential predictive factors of treatment activity or efficacy

The primary study end-point is Response rate (RECIST vers. 1.1) Mini-max, two-stage design by Simon alpha and beta errors of 0.05 and 0.20, respectively p0 (RR in null hypothesis) of 0.60 p1 (RR in alternative hypothesis) of 0.80 A total of 35 evaluable patients will be enrolled (considering an incidence of RAS and BRAF mutations around 50%, a total of around 70 patients should be screened) If at least 26 response will be observed, the treatment will be considered promising StatisticsStatistics

Histologically confirmed colorectal adenocarcinoma Availability of formalin-fixed paraffin embedded tumor block from primary or metastasis RAS and BRAF wild-type status of primary colorectal cancer or related metastasis Unresectable and measurable metastatic disease (RECIST criteria) Adjuvant chemotherapy ended more than 12 months before relapse Age ≥ 18 years and ≤ 75 years ECOG PS ≤ 2 if aged < 71 years and ECOG PS = 0 if aged years Adequate hematological, liver and kidney function Prior palliative chemotherapy Prior treatment with EGFR inhibitors Symptomatic peripheral neuropathy ≥ 2 grade according to NCIC-CTG criteria Main Enrollment Criteria

No. (%) Pts screened87 (100%) Pts enrolled37 (43%) Pts not enrolled50 (57%) 1. RAS mutation35 (40%) 2. BRAF mutation4 (5%) 3. Patient refusal2 (2%) 4. Mutational analysis failure6 (7%) 5. Medical decision despite wild-type status3 (3%) Screening and Enrollment

No. = 37 pts Age, median (range)63 years (33-72) Sex Male/Female57% / 43% ECOG PS 0/1-276% / 24% Primary Colon/Rectum70% / 30% Primary on site42% Sites of mets 1/≥254% / 46% Liver only mets35% Previous adjuvant CT Yes/No16% / 84% No. of treatment (ind+mant) cycles492 Median No. of treatment (ind+mant) cycles (range)13 (3-26) Median No. of treatment (ind only) cycles (range)11 (3-16) Patient characteristics

Safety: results before amendment Scheduled dose of 5FU before amendment was 3000 mg/sqm 2 out of the first 3 pts treated with the initially scheduled dose of 5FU experienced severe mucosal toxicity: 1 pt experienced grade 4 diarrhea and febrile neutropenia 1 pt experienced grade 3 diarrhea Both pts were hospitalized due to toxicity, which resolved without sequelae Because of the toxicities observed, study protocol was amended and 5FU dose reduced to 2400 mg/sqm

Maximum per patient toxicities after amendment 34 pts assessed Grade 1-2Grade 3-4 Neutropenia27%53% Febrile neutropenia6% Anemia88%0% Thrombocytopenia56%0% Nausea/Vomiting70% / 44%12% / 3% Diarrhea62%35% Stomatitis53%18% Cutaneous rash68%24% Asthenia62%29% Neurotoxicity (grade 2-3)35%

Maximum per cycle toxicities after amendment 34 pts assessed 447 cycles administered Grade 1-2Grade 3-4 Neutropenia 17%6% Febrile neutropenia<1% Anemia58%0% Thrombocytopenia17%0% Nausea/Vomiting21% / 8%1% / <1% Diarrhea34%4% Stomatitis18%1% Cutaneous rash59%3% Asthenia31%3% Neurotoxicity (grade 2-3)10%

Serious Adverse Events (SAEs) after amendment 34 pts assessed All SAEs 17 events requiring hospitalization or resulting in death Type of SAEs Febrile neutropenia and sepsis (resulting in death) Sudden cardiac death (after surgery on mts) G4 Diarrhea + G3 NeutropeniaPenumonitis (resulting in death) G4 Neutropenia + G3 StomatitisBowel obstruction Chest pain + G3 Diarrhea + G4 Stomatitis Febrile neutropenia + G3 Diarrhea Chest pain + G3 Diarrhea G3 Stomatitis + Hematemesis due to gastric ulcer G4 Diarrhea + G3 Asthenia/Anorexia Bowel sub-obstruction G4 Diarrhea + G3 Asthenia/Anorexia 2 Venous thromboembolic events G4 Hypokalemia + G4 NeutropeniaNecrotizing fascitis

Treatment administration during INDUCTION THERAPY 337 cycles administered 5FULOHPCPT-11P-mab DOSE REDUCTIONS* 28 (8%)34 (10%)32 (9%)27 (8%) MEDIAN DOSE INTENSITY 79%75%74%81% DOSE DELAYS DUE TO TOXICITY* 32 (9%) - 15 (4%) due to SAEs SECONDARY G-CSF SUPPORT* 46 (14%) Reported after amendment *Data are expressed as No. (%) of cycles

Response Rate All 37 pts have been evaluated for response Best response is as follows: 34 pts achieved Objective Response (ORR: 92%) 2 pts (5%) achieved Disease Stabilization 1 pt (3%) progressed during treatment

Conversion to resectability Up today 15 pts (41%) underwent local procedures on metastases (R0 in 12 pts, 32% ) Among the 13 pts with liver-only disease, 10 pts (77%) underwent local procedures (surgery +/- RFA) on metastases (R0 in 9 pts, 69%) 3 pts achieved pathologic complete response

Activity: Maximum tumour shrinkage

Efficacy: Progression-free survival (PFS) Median follow up: 12.2 months No. of pts: 37 No. of events: 24 Median PFS: 10.8 months

- Combining a triple drug regimen such as FOLFOXIRI with Panitumumab seems feasible. - However, treatment is associated with a relatively high incidence of severe mucosal toxicity (mainly diarrhea), therefore, a reduced dose of 5-FU and irinotecan compared with standard GONO- FOLFOXIRI is required. - The primary end-point was met: in molecularly selected patients, FOLFOXIRI-Panitumumab achieved an ORR > 90%, leading to radical resection of metastases in 32% of the patients. - Median PFS appears promising (mPFS: 10.8 months), while mOS has not been reached at a median follow-up of 12.2 months. CONCLUSIONSCONCLUSIONS