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Randomized Phase II Trial of Cetuximab/Bevacizumab/Irinotecan versus Cetuximab/Bevacizumab in Irinotecan-Refractory Colorectal Cancer. LB Saltz, HJ Lenz, H Kindler, H Hochster, S Wadler, P Hoff, N Kemeny, E Hollywood, M Gonen, S Wetherbee, H Chen. Objectives.
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Randomized Phase II Trial of Cetuximab/Bevacizumab/Irinotecan versus Cetuximab/Bevacizumab in Irinotecan-Refractory Colorectal Cancer LB Saltz, HJ Lenz, H Kindler, H Hochster, S Wadler, P Hoff, N Kemeny, E Hollywood, M Gonen, S Wetherbee, H Chen
Objectives • To evaluate the safety and efficacy of concurrent administration of cetux + bev, with and without irinotecan, in irinotecan-refractory colorectal cancer. • Secondary objective: assessment of TTP and RR in each arm, with exploratory comparison between arms
Background • Cetuximab: human-murine chimeric monoclonal antibody that targets the ligand binding site of the epidermal growth factor receptor (EGFR). • Bevacizumab: humanized monoclonal antibody that targets vascular endothelial growth factor (VEGF).
Cetuximab in CPT-11-Refractory CRC • Cetux + Irino: • 23% RR (ASCO 2001, Saltz et al) • 23% RR (ASCO 2003, Cunnigham et al) • Cetux alone • 9% RR (ASCO 2002, Saltz et al) • 11% RR (ASCO 2003, Cunningham et al) • 12% RR (ASCO 2004, Lenz et al)
Bevacizumab in CRC • Improved RR, TTP, OS with 1st line IFL • (ASCO 2003, Hurwitz et al) • 1% RR with 5FU/LV in refractory CRC • (ASCO 2004 Chen et al) • Improved OS with 2nd line FOLFOX • (ASCO GI 2005, Giantonio et al)
Entry Criteria • Measurable metastatic colorectal cancer. • Prior tumor growth on irinotecan or irinotecan-containing regimen. • As judged by the treating investigator • Rise in CEA alone not acceptable • May not have discontinued irinotecan for tox only • Any number of prior regimens acceptable. • ECOG 0-1. • Normal renal, hepatic, and bone marrow function. • No prior anti-EGFR or anti-VEGF therapy
Study Design • Randomized phase II • EGFR expression not required for study entry • Initially planned for 75 pts/arm • Statistics recalculated for 37 pts/arm
Treatment Plan • Arm A (CBI) • Cetuximab, 400 mg/m2 loading dose, then 250 mg/m2 weekly • Bevacizumab 5 mg/kg every other week • Irinotecan at same dose and schedule as last given prior to study entry • Arm A (CB) • Cetuximab, 400 mg/m2 loading dose, then 250 mg/m2 weekly • Bevacizumab 5 mg/kg every other week
Treatment Plan • Cetuximab +/- irintoecan given day 1, and bevacizumab given day 2, week 1 only. • Seen for office visit at least every other week. • Evaluated by CT or MRI every 6 weeks. • Toxicity graded on CTCAE 3.0
Adverse events: GI (n=74) • Lower GI Bleed: (Pt with carcinomatosis explored for lower GI bleed. Found necrotic tumor eroding into small bowel – felt to be POD) • Rectal Fistula: (Pt developed rectal fistula in setting of carcinomatosis and POD) • UGI bleed. (Endoscopy revealed non-perforating duodenal ulcer) • Enterococcal Endocarditis: Pt admitted with HGB =6, creat =5. W/u revealed enterococcal sepsis with echo showing severe TR and AI with cardiac vegetation. Pt expired in hospital.
Adverse Events:Arterial Thrombotic (n=74) • CNS lacunar infarct: (MRI showed right frontal lobe lacunar infarct. Also showed many chronic lacunar infarcts and chronic microvascular ischemic changes). • MI: (Pt with hx of diabetes, HTN, anemia, and neuropathy, experienced MI on week 22 of treatment. Admitted to local hospital for 10 days. Discharged, then died at home 6 days later, from presumed further cardiac event.) • Chest pain: (Atypical chest pain 80 minutes into 1st bev infusion. Enzymes and ECG’s negative for MI. No chest pain with subsequent treatments. Later admitted with new chest pain, had new a-fib and UE-DVT).
Efficacy of CBI (n=41) • Partial Response 15 (37%) • 95% CI 22%- 53% • Median TTP 7.9 months • Range (1+ to 16+ months)
Efficacy of CB (n=40) • Partial Response 8 (20%) • 95% CI 9%-36% • Median TTP 5.6 months • Range ( 1+ to 12+ months)
Pending Scientific Correlates(Tissue and blood collected) • Cetuximab PK with and without Bev • Bevacizumab PK • Tissue (archived) for PCR • UGT1A1, topo 1, ERCC-1, XRCC-1, p53, GSTP1, p21, p27 VEGF, E-cadherin, TP, COX-2, TGFβ, EGFR • Germ line polymorphisims (peripheral blood) • UGT1A1, XPD, XRCC-1, XRCC-3, ERCC-1, GST-P1 VEGF, TGFβ, COX-2, EGFR • Plasma for VEGF levels • at baseline, 6, 12, and 18 weeks.
Conclusions • Concurrent adminstration of cetuximab and bevacizumab is feasible. • Toxicities are as would be predicted from the individual agents, without clear indication of synergistic toxicity
Conclusions • Compared with historical controls, bevacizumab appears to add to the efficacy of cetuximab and cetuximab/irinotecan in irinotecan-refractory, bevacizumab-naïve colorectal cancer patients. • The usefulness of bevacizumab with cetuximab in patients with prior bevacizumab exposure remains unknown. Studies to address this question are in development.
BOND STUDIES • BOND 1 cetux-irino vs cetux • BOND 2 cetux-bev-irino vs cetux-bev (in bev-naïve patients) • BOND 3 cetux-bev-irino vs cetux-bev (in bev-refractory patients)
BOND STUDIES • BOND 1 cetux-irino vs cetux • BOND 2 cetux-bev-irino vs cetux-bev (in bev-naïve patients) • BOND 2.5 cetux-bev-irino (single arm phase II) (in bev-refractory patients) • BOND 3 cetux-bev-irino vs cetux-bev (in bev-refractory patients)
Planned GI Intergroup CRC Study(Alan Venook and Charles Blanke, PI’s) • Investigator’s choice: FOLFOX vs FOLFIRI • Then randomize to add: • Cetuximab • Bevacizumab • Cetuximab + Bevacizumab
Acknowledgments • Patients, their families and caregivers • Centers – MSKCC, USC, U Chicago, NYU, Cornell, MDA • Industry – Genentech, Imclone/BMS • CTEP / NCI