Safety, Tolerability, PK, Anti-Tumor Activity of STP705 in Subjects With Advanced/Metastatic or Surgically Unresectable Solid Tumors Who Are Refractory to Standard Therapy

This is an open label, dose escalation and dose expansion study to evaluate the safety, tolerability, pharmacokinetics, and anti-tumor activity of various doses of STP705 administered intratumorally in cholangiocarcinoma, hepatocellular carcinoma or liver metastasis. The primary objective of this study is to determine the MTD or RP2D of STP705 and to establish the dose of STP705 recommended for future phase 2 studies when administered intratumorally. A total of up to 30 patients will be enrolled in the dose escalation phase of the study. In addition, once the MTD or recommended phase 2 dose has been established, up to 20 additional patients maybe enrolled to confirm safety and explore anti-tumor activity. Up to five dose levels will be explored (20,40,80,160,320 μg dose levels) and will depend on the number and intensity of observed toxicity. Intermediate doses maybe explored during escalation period. It will follow an accelerated titration design, enrolling 1 patient per dose cohort and will expand to a standard 3+3 design after. In the accelearted titration a Grade 2 SE triggers the transition to the 3+3 part of the study. The 3+3 part of the study will start at dose level 160μg. Subjects will be evaluated for DLTs in the first cycle of treatment and graded aacording to NCI CTCAE v5. A cycle is 28 days.