LAUSR

679 Background: First-line (1L) antiendothelial growth factor receptor (anti-EGFR) is considered suitable in metastatic colorectal cancer (mCRC) patients. As no treatment guidelines recommend target therapy sequence in mCRC, this meta-analysis determined the optimal sequence of targeted therapies in patients with KRAS wild type (WT) mCRC. Methods: PICO framework was used to retrieve relevant studies from PubMed, Embase, Cochrane Library and Google Scholar. mCRC patients treated with 1L anti-EGFR and second-line (2L) anti -VEGF were compared with 1L anti-VEGF and 2L anti-EGFR treatment (gp. A). Patients treated with 1L anti-VEGF and 2L anti-EGFR treatment were compared with anti-VEGF in 1L and 2L (gp. B). We also compared 2L and 3L anti-EGFR therapies (gp. C). Primary and secondary outcomes of overall survival (OS) and progression free survival (PFS) were presented as hazard ratio (HR) and 95% confidence intervals (95% CIs). Objective response rate (ORR) was evaluated in terms of relative risk (RR) and 95% CI. P < 0.05 was considered statistically significant. Results: We identified nine studies for this analysis including 1478 KRAS WT mCRC patients. In gp. p A (three studies; two retrospective and one post-hoc analysis; 450 patients), 1L anti-EGFR and 2L anti-VEGF treatment had a significantly higher OS (HR 0.83, 95% CI 0.53-1.32; p = 0.0022) and PFS (HR 0.85, 95% CI 0.76- 0.96; p = 0.0081) than 1L anti-VEGF and 2L anti-EGFR. Comparison in gp. B (n = 3 RCTs involving 431 mCRC KRAS WT patients) showed no significant difference in OS (HR 0.95, 95% CI 0.70- 1.29; p = 0.6897; I2 = 42.69%) and PFS (HR 1.43, 95% CI 0.83- 2.47; p = 0.1962; I2 = 81.55%) between the two lines of treatment. ORR was higher with anti-VEGF in both 1L and 2L in gp. B (RR 3.58, 95% CI 0.72- 17.85; p = 0.1191). In gp. C, indirect comparison showed similar OS with 3L and 2L anti-EGFR therapies ((3L and 2L: n = 2 studies each; HR 0.86. 95% CI 0.71-1.04; HR 0.78, 95% CI 0.51-1.20; 2L vs. 3L; p = 0.06). Conclusions: Patients with KRAS WT mCRC achieved maximum benefit with 1L anti-EGFR and 2L anti-VEGF than with 1L anti-VEGF and 2L anti-EGFR or 1L and 2L anti-VEGF. Hence, it is suggested to initiate the therapy with 1L anti-EGFR to derive the maximum clinical benefit.