A KRAS mutation status-stratified randomized phase II trial of gemcitabine and oxaliplatin alone or in combination with cetuximab in advanced biliary tract cancer

Addition of cetuximab showed trend, but not significantly, to improve the therapeutic effects of gemcitabine and oxaliplatin combination for advanced biliary tract cancer in current randomized phase II trial. The trend of improvement did not correlate with KRAS mutation status. Biomarkers finding for selecting patients who will benefit most from anti-EGFR targeted therapy is warranted. Background Previous clinical trials have not proved that adding epidermal growth factor receptor inhibitors to chemotherapy confers a survival benefit for patients with advanced biliary tract cancer (ABTC). Whether the KRAS mutation status of tumor cells confounded the results of past studies is unknown. Patients and methods ABTC patients stratified by KRAS status, Eastern Cooperative Oncology Group performance status, and primary tumor location were randomized 1 : 1 to receive GEMOX (800 mg/m2 gemcitabine and 85 mg/m2 oxaliplatin) or C-GEMOX (500 mg/m2 cetuximab plus GEMOX) every 2 weeks. The primary end point was objective response rate (ORR). Results The study enrolled 122 patients between December 2010 and May 2012 (62 treated with C-GEMOX and 60 with GEMOX). Compared with GEMOX alone, C-GEMOX was associated with trend to better ORR (27% versus 15%; P = 0.12) and progression-free survival (PFS, 6.7 versus 4.1 months; P = 0.05), but not overall survival (OS, 10.6 versus 9.8 months; P = 0.91). KRAS mutations, which were detected in 36% of tumor samples, did not affect the trends of difference in ORR and PFS between C-GEMOX and GEMOX. The two treatment arms had similar adverse events, except that more patients had skin rashes, allergic reactions, and neutropenia in the C-GEMOX arm. Of patients with C-GEMOX, the presence of a grade 2 or 3 skin rash was associated with significantly better ORR, PFS, and OS. Conclusions Addition of cetuximab did not significantly improve the ORR of GEMOX chemotherapy in ABTC, although a trend of PFS improvement was observed. The trend of improvement did not correlate with KRAS mutation status. Clinical Trials number This study is registered at ClinicalTrials.gov (NCT01267344). All patients gave written informed consent.