A Study of MHB088C Injection Versus Treatment of Physician's Choice in Subjects With Relapsed Small Cell Lung Cancer

This study tests a new drug called MHB088C in people with small cell lung cancer (SCLC) that has spread throughout the body and stopped responding to standard treatments. Small cell lung cancer grows quickly and has limited treatment options once it progresses, so researchers are looking for new approaches. **You may be eligible if...** - You are 18 or older with confirmed extensive-stage small cell lung cancer (cancer that has spread widely) - Your cancer progressed after at least two rounds of treatment including platinum-based chemotherapy and an immunotherapy drug (PD-1/L1 inhibitor) - You have not received more than two prior treatment regimens - You have at least one measurable tumor and good organ function **You may NOT be eligible if...** - You have another active cancer diagnosed in the last 5 years - You have a mixed or transformed type of lung cancer (not pure SCLC) - You received chemotherapy within the past 4 weeks - Your overall health is not strong enough to tolerate cancer treatment Talk to your doctor to see if this trial is right for you.