A Trial of the Combination of Afatinib and Palbociclib in Previously Treated Advanced Esophageal Squamous Cell Carcinoma

The goal of this clinical trial is to learn if Afatinib plus Palbociclib works in previously treated recurrent or metastatic esophageal squamous cell carcinoma. It will also learn about the safety of the combination of Afatinib and Palbociclib. The main questions it aims to answer are: What is the safe and tolerable dose of Afatinib when combined with 100 mg of Palbociclib (administered orally, three weeks on and one week off)? Does the combination therapy of Afatinib and Palbociclib induce a tumor response in patients with recurrent or metastatic esophageal squamous cell carcinoma who have received prior treatments?