The term of biliary tract cancer (BTC) refers to all tumors that arise from the biliary tract or the biliary drainage system, including the gallbladder.Biliary tract cancer is one of the most poorly prognosis cancers and the five-year survival rate remains at about 10% as it is difficult to expect long-term survival due to frequent local recurrence and remote metastasis after surgery.~South Korea belongs to a country with a high number of biliary tract cancer patients, and the incidence of biliary tract cancer is actually increasing every year.According to the 2018 National Cancer Registration Statistics, the number of 5-year biliary tract cancer patients was 13,967 (7,547 men and 6,420 women), which corresponds to about 2.9% of all cancersand the 5-year survival rate of biliary tract cancer patients between 2014 and 2018 was 28.8%, showing a lower survival rate than other cancer species.~Most of the long-term survival is due to early detection by screening, but advanced carcinoma is a refractory carcinoma with a 5-year survival rate of less than 5%.In addition to standard anticancer drugs, alternative anticancer drugs and targeted treatments can be developed for cancer with a large number of patients, but biliary tract cancer is difficult to find any more treatments if standard treatment fails and standard anticancer treatments cannot be continued due to resistance.~Natural killer cells (NK cells) are innate lymphocyte cells with cell killing activity, and have the characteristic of destroying cells by secretion of and granzyme into cancer cells and abnormal cells that are reduced or deficient in expression of MHC class I.Clinical studies using natural killer cells as anticancer drugs have long been conducted on various cancers.~Pembrolizumab is a monoclonal antibody designed to bind to a receptor called PD-1, which is expressed by immune cells such as T cells.Natural killer cells were also found to be expressing PD-1 in the same way as T cells, and in particular, PD-1 was found to be higher in cancer patients than in healthy people.~Therefore, combined therapy with the immune-check point such as pembrolizumab can be useful in elevating the anticancer activity of NK cells.
This study is designed to assess the antitumor activity of combination therapy of SMT-NK (allogeneic natural killer cells) and pembrolizumab versus pembrolizumab monotherapy in patients with advanced biliary tract cancer