Treatment Patterns and Outcomes in Patients with KRAS Wild-Type Metastatic Colorectal Cancer Treated in First Line with Bevacizumab- or Cetuximab-Containing Regimens
Patients with Kirsten rat sarcoma viral oncogene wild-type (KRAS WT) metastatic colorectal cancer (mCRC) treated in first line with bevacizumab (B) or cetuximab (C) plus standard chemo backbones had comparable outcomes in phase III Cancer and Leukemia Group B (CALGB) 80405. We examined comparative effectiveness of B and C regimens in real-world community settings.
This retrospective study examined progression-free survival (PFS) and OS in a US community sample of KRAS WT mCRC patients treated with first-line B (n = 254) or C (n = 146) regimens. Medical records from the Vector Oncology Data Warehouse were used. Disease progression was determined from patient charts. OS was measured from the start of first-line treatment until death.
There were no significant difference in either PFS or OS respectively between B-treated compared to C-treated patients (HR = 1.324, 95% CI 0.901, 1.947; HR = 1.080, 95% CI 0.721, 1.617). More B patients received oxaliplatin backbones (74.8 vs. 36.3%), and more C patients received irinotecan backbones (51.4 vs. 20.1%), ps < 0.001. Multivariate survival analyses showed a significant difference indicating a greater risk for death among C-treated patients with right-sided tumors vs. left-sided tumors (HR = 2.263, 95% CI 1.394, 3.673, p = 0.0009), but not for B-treated patients (HR = 1.209, 95% CI 0.825, 1.771, p = 0.3297).
Consistent with CALGB 80405, median PFS and OS for these community oncology KRAS WT mCRC patients treated with first-line B or C regimens did not differ significantly.
KeywordsComparative effectiveness Community oncology Progression-free survival Overall survival Tumor location
This work was funded by Genentech, Inc.
Compliance with Ethical Standards
Conflict of Interest
AH reported no conflict of interest. SO and NS are employed by and own stock in Genentech, Inc. SSH and MW are consultants for Genentech. Genentech sponsored this study and provided financial support for the conduct of the research and for preparation of the article. Genentech collaborated on the design of the study, interpretation of the analyses, and in the decision to submit the article for publication, but did not have a direct role in data collection, data analysis, or writing of the report.
Research Involving Human Participants
This research was reviewed and approved by IntegReview Institutional Review Board, in Austin, TX. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
For this type of study, formal consent is not required.
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