Prospective Multiomic Analysis in Small-Cell Lung Cancer

This is an observational study to collects blood samples and tumor tissue from adults with relapsed small-cell lung cancer (SCLC) receicing standard of care commercial DLL3 T cell engager. The goal of the study is to understand the changes in tumor markers over time and examine whether these changes are associated with clinical outcomes. Participants will provide blood samples and, when clinically feasible, tumor tissue during routine care visits, treatment, and imaging assessments. The study does not assign cancer treatment.