Study of ISU104, Targeting ERBB3 in Patients With Advanced Solid Tumors

\[Part 1 Dose-escalation\] This study ams to evaluate the safety, tolerability, and pharmacokinetics of ISU104 in patients with advanced solid tumors. Primary objective To determine recommended Phase II dose (RP2D) of ISU104 based on the results of its safety and tolerability in patients with advanced solid tumors. Secondary objectives 1. To evaluate pharmacokinetics (PK) of ISU104 in patients with advanced solid tumors. 2. To evaluate efficacy of ISU104 in patients with advanced solid tumors. Exploratory purpose To identify the expression of explorable multiple tumor biomarkers and to analyze the relationship between biomarkers and antitumor activity of ISU104. \[Part 2 dose-expansion\] The purpose of this study is to evaluate the safety, tolerability, and pharmacokinetics of ISU104 in patients with recurrent/metastatic HNSCC (except for nasopharyngeal cancer), when administered intravenously ISU104 alone or ISU104 in combination with cetuximab. Primary objective To determine RP2D of ISU104 based on results of its safety and tolerability in patients with recurrent/metastatic HNSCC (except for nasopharyngeal cancer), when administered intravenously ISU104 only or ISU104 in combination with cetuximab. Secondary objectives 1. To evaluate the pharmacokinetics of ISU104 in patients with recurrent/metastatic HNSCC (except for nasopharyngeal cancer), when administered intravenously ISU104 only or ISU104 in combination with cetuximab. 2. To evaluate the efficacy of ISU104 in patients with recurrent/metastatic HNSCC (except for nasopharyngeal cancer), when administered intravenously ISU104 only or ISU104 in combination with cetuximab. Exploratory purpose To explore a variety of detectable tumor biomarkers and evaluate the relationship between these biomarkers and antitumor activity of ISU104.