Liver metastases occurred in

63/104 (60.6%) of KRAS WT and 41/77 (53.3%) of KRAS MT (P=0.36). Lung metastases occurred in 34/104 (32.7%) of KRAS WT and 24/77 (31.2%) of KRAS MT (P=0.87). Peritoneal metastases occurred in 27/104 (26%) of KRAS WT and 13/77 (16.9%) of KRAS MT (P=0.15). Table 3 Pattern of metastatic disease and clinical outcome based on KRAS status KRAS mutations and outcome with first-line FOLFOX +/- bevacizumab Out of 181 patients with metastatic Inhibitors,research,lifescience,medical disease, 83 received first line FOLFOX (+/- bevacizumab) chemotherapy at RPCI and were evaluable for response. Among the response-evaluable patients, 44/53 (83.02%) and 24/30 (80%) received bevacizumab in EX 527 solubility dmso combination with FOLFOX in the KRAS WT and MT populations, respectively (P= 0.771). The best overall response rate was 56.60% (27/53 PR and 3/53 CR) in KRAS WT and 50% (15/30 PR) in KRAS mutant patients Inhibitors,research,lifescience,medical (P=0.64).

None of the patient with KRAS mutation had CR. Twenty one patients (39.6%) had stable disease in KRAS WT and 15 (50%) in KRAS mutant patients (Table 3). The median PFS was 9.3 months (95% CI, 7.85 to 10.78) in KRAS WT and 8.7 months (95% CI, 5.42 to 15.18) in KRAS MT populations (P=0.395, log-rank test) (Fig 3). Patients with resection of metastatic disease after first-line FOLFOX (+/- bevacizumab) Inhibitors,research,lifescience,medical were not included for estimation of PFS. Seven patients in KRAS MT population and four patients in KRAS WT population had resection of metastatic Inhibitors,research,lifescience,medical disease after first line chemotherapy. Median OS was 34.8 months (95% CI, 23.5-42.5) in KRAS WT and not achieved in MT patients (Fig 4). Figure 3 Kaplan-Meier survival analysis for progression-free survival

time according to KRAS status (P=0.3954). Figure 4 Kaplan-Meier survival analysis for overall survival (OS) time according to KRAS status (P=0.7407). Median OS was not achieved. Discussion Several studies have reported that WT KRAS status of tumor is predictive of response to addition of EGFR inhibitors Inhibitors,research,lifescience,medical (cetuximab or panitumumab) in chemotherapy regimens involving oxaliplatin (FOLFOX or XELOX) (21),(24). Although the combination else of EGFR inhibitors with first-line FOLFOX or XELOX significantly enhanced the clinical outcome in patients with WT KRAS tumors in several studies, the effect of KRAS status on patients receiving FOLFOX alone or FOLFOX plus bevacizumab remains uncertain. Table 1 summarizes effect of KRAS mutation on clinical outcome of patients treated with FOLFOX or XELOX in various studies. In the phase II OPUS (Oxaliplatin and Cetuximab in First-Line Treatment of metastatic CRC) study, patients with KRAS mutation had a trend to a better response rate and PFS when treated with FOLFOX-4 alone when compared to patients with WT KRAS.