Small Cell Lung Cancer Irinotecan and CDC2-like Kinase Inhibition Trial (SLICK Trial)

This study (SLICK Trial) is testing a combination of irinotecan (a standard chemotherapy) and a new drug called cirtuvivint (which targets a cell division protein called CLK) in people with small cell lung cancer that has progressed after prior platinum-based chemotherapy. **You may be eligible if...** - You are 18 or older - You have confirmed small cell lung cancer that has come back or progressed after at least one prior platinum-based chemotherapy regimen - You have at least one measurable tumor - Your blood counts and organ function are adequate - You are willing to use contraception during and after treatment - Brain metastases are allowed if they have been treated and are stable (or are small and asymptomatic) **You may NOT be eligible if...** - You previously stopped irinotecan due to treatment-related side effects - You are currently on another experimental drug - You have untreated or symptomatic brain metastases - You have active inflammatory bowel disease or significant liver disease (e.g., cirrhosis) - You have unresolved serious side effects from prior treatment - You are pregnant or breastfeeding - You have HIV with undetectable viral load not achieved or active hepatitis B/C - You have known retinal eye disease - You have a significantly prolonged heart rhythm (QT interval above 480ms) Talk to your doctor to see if this trial is right for you.