MEK162 in Combination With Capecitabine in Advanced Biliary Tract Cancer

Biliary tract cancer is one of rare cancers, which is relatively more frequent in east Asia. The frequency of KRAS mutation and/or BRAF mutation is reported at 40 to 60%. The prognosis is still very poor, with only limited treatment options. The most commonly used 1st-line chemotherapy is gemcitabine+cisplatin combination. In gemcitabine-pretreated advanced biliary tract cancer, fluoropyrimidine-based chemotherapy is used. However, the overall survival with these cytotoxic chemotherapies is still only about 8-10 months, calling for urgent development of efficient treatment options. Recently, mitogen-activated extracellular signal regulated kinase kinase (MEK) inhibition was shown to have antitumor effects in KRAS mutated biliary tract cancers in preclinical model. In phase II study of MEK inhibitor (selumetinib) in metastatic biliary tract cancers, selumetinib displayed interesting activity and acceptable tolerability. MEK162 is an oral, highly selective MEK inhibitor. It was shown to promote apoptosis and in vivo antitumor activity against human biliary tract cancer cell lines. So far, there has been no study to test the MEK inhibitor mainly in gemcitabine-pretreated advanced biliary tract cancer, especially in combination of capecitabine chemotherapy. The aim of this study is to test the efficacy of MEK162 plus capecitabine in gemcitabine-pretreated advanced biliary tract cancer, and to explore the predictive biomarkers for future large-scale clinical trials using this combination.