This is a multicenter, open-label, phase I/ II clinical study, including phase I dose escalation period and phase II trial period.~The phase I dose escalation period will adopt a 3+3 dose escalation design. Three dose groups are designed as follows:~Level 1: 150 mg/m2 PT-112 (Phosplatin's platinum) + 1000 mg/m2 gemcitabine; Level 2: 200 mg/m2 PT-112 + 1000 mg/m2 gemcitabine; Level 3: 250 mg/m2 PT-112 + 1000 mg/m2 gemcitabine. If any DLT(Dose-Limiting Toxicity ) occurs in Level 1 group during dose escalation, the dose will be down titrated to Level-1 150 mg/m2 PT-112 + 800 mg/m2 gemcitabine. After the lowest dose group (Level-1 or Level 1), the dose of gemcitabine will be fixed while the dose of PT-112 will be up titrated.~During the phase I dose escalation period, sufficient data will be obtained to demonstrate that the dose is safe. Investigators and sponsor will discuss and decide the initiation time of the phase II period. In phase II, it is planned to enroll subjects with biliary tract cancer according to Simon's two-stage study design, to assess the safety and anti-tumor efficacy of PT-112 in combination with gemcitabine for treating patients with advanced biliary tract cancer. In the first period, 23 evaluable subjects are intended to be enrolled. If ≤ 12 subjects have disease control (CR(Complete Response) + PR(Partial Response) + SD(Stable Disease)) at the first post-baseline tumor assessment, the study drug will be considered to be ineffective and the trial terminated; if >12 subjects have disease control (CR + PR + SD), the enrollment for phase II will be initiated. In total, 37 evaluable subjects will be enrolled. The study drug will be considered to be ineffective if a total of ≤23 subjects have disease control (CR + PR + SD).
Phase I dose escalation period: solid tumors, including but not limited to biliary tract cancer, pancreatic cancer, ovarian cancer, thymoma, neuroendocrine carcinoma and other advanced solid tumors.~Phase II trial period: biliary tract cancer