Study of Dalpiciclib Isethionate Plus Pyrotinib Maleate in the Treatment of Advanced Esophageal Squamous Cell Carcinoma

This study tests a combination of two targeted drugs — dalpiciclib and pyrotinib — in people with advanced esophageal squamous cell cancer that has come back or spread after prior chemotherapy. **You may be eligible if...** - You are 18–75 years old - You have been diagnosed with advanced or metastatic esophageal squamous cell carcinoma - Your cancer has progressed or you could not tolerate first-line chemotherapy - You have at least one measurable tumor on a scan - You are physically functional (ECOG 0–1) - Your blood counts and organ function meet the required levels **You may NOT be eligible if...** - You have uncontrolled fluid buildup around the lungs or abdomen - You have chronic diarrhea, intestinal obstruction, or bowel disease - You received other anti-cancer treatment within the past 4 weeks - You have brain metastases that are untreated or causing symptoms - You have a history of another cancer in the past 5 years - You have serious heart problems - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.