Assessment of treatment with panitumumab, cetuximab, and bevacizumab among mCRC patients with wild-type RAS or BRAF treated at community cancer centers in the United States.

Abstract

663 Background: There is limited observational data on the use of RAS test results and treatment patterns with chemotherapy and biologics among metastatic colorectal cancer (mCRC) patients. Our objective was to use real world data to evaluate the treatment sequences of mCRC patients who have wild-type RAS (KRAS, NRAS), or BRAF and who are treated at community cancer clinics within the United States (U.S.). Methods: The sample included 536 patients in the Oncology Services Comprehensive Electronic Records (OSCER) database who were diagnosed with mCRC between 1/1/2011 and 8/31/2015. All patients had available treatment data and were confirmed to have wild-type RAS or BRAF. Patients were stratified into mutually-exclusive categories based on 1st line treatment with chemotherapy in combination with either bevacizumab (Bmab), cetuximab (Cmab), panitumumab (Pmab), a combination of Pmab, Cmab or Bmab, or no biologics. Descriptive statistics were used to summarize the data. Results: The demographics of the sample were as follows: mean age 67 years (standard deviation = 12), 55% male, 70% White, and 50% with ECOG value of zero. The use of Bmab, Cmab, or Pmab in combination with chemotherapy in 1st line treatment was follows: Bmab only (n = 270, 50%), Cmab only (n = 81, 15%), Pmab only (n = 28, 5%), and a combination of either Bmab, Cmab and/or Pmab (n = 6, 1%). No biologics were administered to 151 (28%) of the sample in 1st line. There were no statistically significant differences in age, gender, race, insurance type, region of the U.S. or ECOG status at mCRC diagnosis across the 1st line treatment categories. Of the 385 patients who received a biologic in 1st line, 94 (24%) of those who survived and selected to continue treatment received a biologic in 2nd line. Of these 94 patients, 25 (27%) of those who survived and selected to continue treatment also received a biologic in 3rd line. Conclusions: Bmab was the most commonly-used biologic among mCRC patients with wild-type RAS or BRAF in this descriptive study. Future research is needed to better understand what factors impact treatment decisions among mCRC patients.