This study will have three parts, phase 1 dose escalation (Part 1), phase 1 dose expansion (Part 2)， and phase 2 combination therapy (Part 3).~Subjects will receive SC0245 and Irinotecan combination therapy. The study is composed of 67 subjects.~Irinotecan 80mg/m2 via IV administered for every 4 weeks (fixed dosing) in Day 1 Day8 and Day 15 of each cycle, and SC0245 administered with a 3-day on and 4-day off schedule in Day 1 Day8 and Day 15 of each cycle. One cycle is consisted of 28 days.~Study treatment will be continued until objective disease progression (unless other criteria for treatment discontinuation are met). Tumor evaluation using CT or MRI by RECIST 1.1 every 8weeks(±1week) until objective disease progression. RECIST 1.1 scans will be analyzed by the investigator on site. If a subject discontinues study treatment prior to disease progression, they should continue to be assessed using RECIST 1.1 until disease progression and then followed up for survival.~Primary Objective:~Part 1 (phase 1 dose escalation): To determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of SC0245 in combination with irinotecan in patients with advanced solid tumors.~Part 2 (phase 1 dose expansion): To evaluate the safety and tolerability of SC0245 in combination with irinotecan in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC).~Part 3(phase 2 combination therapy): To evaluate the preliminary anti-tumor activity of SC0245 in combination with irinotecan in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC).~Secondary Objective:~Part 1 (phase 1 dose escalation): To characterize the PK profile and the preliminary anti-tumor activity.~Part 2 (phase 1 dose expansion): To characterize the PK profile, safety and tolerability and the preliminary anti-tumor activity in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC).~Part 3(phase 2 combination therapy): To characterize the safety and tolerability and the preliminary anti-tumor activity in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC).
This study is a single arm, multi-center, open label phase Ib/II study of SC0245 and Irinotecan combination therapy in subjects with extensive-stage small cell lung cancer (ES-SCLC) as a second therapy. This study will have three parts, phase 1 dose escalation (Part 1), phase 1 dose expansion (Part 2), and phase 2 combination therapy (Part 3).