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

Abstract

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/m(2) gemcitabine and 85 mg/m(2) oxaliplatin) or C-GEMOX (500 mg/m(2) 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.

Keywords: KRAS mutation; biliary tract cancer; cetuximab; chemotherapy.