ABSTRACT
PURPOSE: The antiepidermal growth factor receptor monoclonal antibody cetuximab has improved survival in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer. The addition of brivanib, a tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor and fibroblast growth factor receptor, to cetuximab has shown encouraging early clinical activity. PATIENTS AND METHODS: Patients with metastatic colorectal cancer previously treated with combination chemotherapy were randomly assigned 1:1 to receive cetuximab 400 mg/m(2) intravenous loading dose followed by weekly maintenance of 250 mg/m(2) plus either brivanib 800 mg orally daily (arm A) or placebo (arm B). The primary end point was overall survival (OS). RESULTS: A total of 750 patients were randomly assigned (376 in arm A and 374 in arm B). Median OS in the intent-to-treat population was 8.8 months in arm A and 8.1 months in arm B (hazard ratio [HR], 0.88; 95% CI, 0.74 to 1.03; P = .12). Median progression-free survival (PFS) was 5.0 months in arm A and 3.4 months in arm B (HR, 0.72; 95% CI, 0.62 to 0.84; P < .001). Partial responses observed (13.6% v 7.2%; P = .004) were higher in arm A. Incidence of any grade ≥ 3 adverse events was 78% in arm A and 53% in arm B. Fewer patients received ≥ 90% dose-intensity of both cetuximab (57% v 83%) and brivanib/placebo (48% v 87%) in arm A versus arm B, respectively. CONCLUSION: Despite positive effects on PFS and objective response, cetuximab plus brivanib increased toxicity and did not significantly improve OS in patients with metastatic, chemotherapy-refractory, wild-type K-RAS colorectal cancer.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carcinoma/drug therapy , Colorectal Neoplasms/drug therapy , Drug Resistance, Neoplasm , Genes, ras , Adult , Aged , Alanine/administration & dosage , Alanine/adverse effects , Alanine/analogs & derivatives , Antibodies, Monoclonal, Humanized/administration & dosage , Antibodies, Monoclonal, Humanized/adverse effects , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Carcinoma/genetics , Carcinoma/secondary , Cetuximab , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Disease-Free Survival , Drug Administration Schedule , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Odds Ratio , Protein Kinase Inhibitors/administration & dosage , Protein Kinase Inhibitors/adverse effects , Protein-Tyrosine Kinases/antagonists & inhibitors , Treatment Failure , Triazines/administration & dosage , Triazines/adverse effectsABSTRACT
BACKGROUND: The National Cancer Institute of Canada Clinical Trials Group CO.17 study showed that patients with advanced colorectal cancer had improved overall survival when cetuximab, an epidermal growth factor receptor-targeting antibody, was given in addition to best supportive care. We conducted a cost-effectiveness analysis using prospectively collected resource utilization and health utility data for patients in the CO.17 study who received cetuximab plus best supportive care (N = 283) or best supportive care alone (N = 274). METHODS: Direct medical resource utilization data were collected, including medications, physician visits, toxicity management, blood products, emergency department visits, and hospitalizations. Mean survival times for the study arms were calculated for the entire population and for the subset of patients with wild-type KRAS tumors over an 18- to 19-month period. All costs were presented in 2007 Canadian dollars. One-way and probabilistic sensitivity analysis was used to determine the robustness of the results. Cost-effectiveness acceptability curves were determined. The 95% confidence intervals (CIs) for the incremental cost-effectiveness ratios and the incremental cost-utility ratios were estimated by use of a nonparametric bootstrapping method (with 1000 iterations). RESULTS: For the entire study population, the mean improvement in overall and quality-adjusted survival with cetuximab was 0.12 years and 0.08 quality-adjusted life-years (QALYs), respectively. The incremental cost with cetuximab compared with best supportive care was $23,969. The incremental cost-effectiveness ratio was $199,742 per life-year gained (95% CI = $125,973 to $652,492 per life-year gained) and the incremental cost-utility ratio was $299,613 per QALY gained (95% CI = $187,440 to $898,201 per QALY gained). For patients with wild-type KRAS tumors, the incremental cost with cetuximab was $33,617 and mean gains in overall and quality-adjusted survival were 0.28 years and 0.18 QALYs, respectively. The incremental cost-effectiveness ratio was $120,061 per life-year gained (95% CI = $88,679 to $207,075 per life-year gained) and the incremental cost-utility ratio was $186,761 per QALY gained (95% CI = $130,326 to $334,940 per QALY gained). In a sensitivity analysis, cetuximab cost and patient survival were the only variables that influenced cost-effectiveness. CONCLUSIONS: The incremental cost-effectiveness ratio of cetuximab over best supportive care alone in unselected advanced colorectal cancer patients is high and sensitive to drug cost. Incremental cost-effectiveness ratios were lower when the analysis was limited to patients with wild-type KRAS tumors.
