Comparison of efficacy and toxicity of bevacizumab in combination with chemotherapy in the first, second, and third or higher line of treatment for metastatic colorectal carcinoma (mCRC): Data from the Czech multi-institutional registry.

Abstract

e14622 Background: Data from the Czech national registry of patients treated with targeted therapies for mCRC were analyzed retrospectively to compare treatment outcomes for bevacizumab in combination with chemotherapy in the 1st, 2nd and 3rd line of treatment. Methods: The database was launched in 2005 as a clinical registry of patients with mCRC treated with bevacizumab. Epidemiological and clinical data are entered by all Czech comprehensive cancer centers administering targeted therapy. In total, 4487 mCRC patients who received bevacizumab combined with chemotherapy in either 1st line (n=3990, 88.9%), 2nd line (n=386, 8.6%), or 3rd and higher line (n=111, 2.5%) had evaluable data and were included in the present analysis. Survival was calculated using the Kaplan-Meier method, and the differences were assessed using the log-rank test. Results: Statistically significant differences were observed in the efficacy of combination chemotherapy with bevacizumab between the treatment lines. The objective response rate (ORR) in the 1st, 2nd, and 3rd/higher line was 42.9%, 34.0% and 8.3%; (p<0.001) respectively. Similarly, in the 1st, 2nd, and 3rd/higher line median progression free survival (mPFS) was 11.3 months (95% CI 11.0-11.7 months), 9.5 months (95% CI 8.2-10.9 months) , and 7.3 months (95% CI 5.9-8.7 months; p<0.001), and median overall survival (mOS) was 28.4 months (95% CI 27.1-29.8 months), 25.9 months (95% CI 19.4-32.4 months), and 15.0 months (95% CI 10.7-19.3 months; p<0.001), respectively. The spectrum of the most common adverse events was comparable in the 1st, 2nd, or 3rd/higher line, and incidence of adverse events was similar at 11.6%, 8.8% and 8.1%, respectively. Conclusions: The efficacy of bevacizumab in combination with chemotherapy decreased when administered in later lines of treatment for mCRC while the incidence and spectrum of toxicities remains unchanged.