Emerging drugs for biliary cancer.

INTRODUCTION: The number of biliary cancer patients is small and it is often complicated by serious adverse events making it difficult for clinical studies to be performed on this cancer. However, researches for clarification of the mechanisms of onset and proliferation of biliary cancer and of the effects of drugs suppressing these mechanisms have been initiated recently, with the goal of establishing effective treatments. AREAS COVERED: This review will cover epidemiological and biological features of biliary cancer, the efficacy and limitations of the existing methods of treatment, and current goals for the development of new treatment methods. Furthermore, the findings of pre-clinical studies on promising treatment targets and ongoing clinical studies are also reviewed, and perspectives for the future of treatment are discussed. EXPERT OPINION: Following the recent increase in the interest in drug development, attempts at clarifying the molecular mechanisms underlying the onset and proliferation have been made proactively, accompanied by clinical studies on various molecular-targeted drugs for the treatment of this cancer. To demonstrate the efficacy of these drugs, it is essential to establish a system for efficient screening of patients carrying the molecular targets and to devise an excellent clinical study design.