Envafolimab and Chidamide in combination with GEMOX as first-line treatment for advanced and metastatic biliary tract cancer (B-Enefits/SCOG-B001): A single-arm, exploratory, phase 2 trial

BTC represents a rare malignancy with unfavorable prognosis. Here we conducted a single-arm, multicenter, prospective phase Ⅱclinical study (ChiCTR2400080783) to evaluate the efficacy and safety of envafolimab and chidamide in combination with gemcitabine plus oxaliplatin (GEMOX) as first-line treatment. 10×scRNA-seq was adopted to conduct an initial exploration into the potential mechanisms underlying the efficacy of the combination regimen. Mice subcutaneous cholangiocarcinoma graft models were treated with chidamide at 0, 12.5, 25, and 50 mg/mL. To decipher the complexity of cellular diversity and evolutionary trajectory in immune cell composition in response to chidamide, we obtained one mice tumor of each group after treatment, and the tissues were subjected to scRNA-seq using the 10x Genomics single-cell library. Post-treatment tissue samples were obtained from patients who achieved PR after treatment through surgery or biopsy, and scRNA-seq was performed on two of them.