Pembrolizumab combined with lenvatinib as non-first-line therapy in patients with refractory biliary tract carcinoma

Jianzhen Lin, Xu Yang, Junyu Long, Songhui Zhao, Jinzhu Mao, Dongxu Wang, Yi Bai, Jin Bian, Lei Zhang, Xiaobo Yang, Anqiang Wang, Fucun Xie, Weiwei Shi, Huayu Yang, Jie Pan, Ke Hu, Mei Guan, Lin Zhao, Li Huo, Yilei Mao, Xinting Sang, Kai Wang, Haitao Zhao