Romiplostim N01 Plus ATRA for Persistent Isolated Chemotherapy-Induced Thrombocytopenia After Complete Remission of Gastrointestinal Solid Tumors

This is a prospective, randomized, open-label, active-controlled study to evaluate the efficacy and safety of Romiplostim N01 plus all-trans retinoic acid (ATRA) compared with Romiplostim N01 alone in adults with persistent isolated chemotherapy-induced thrombocytopenia (PICIT) after complete remission of gastrointestinal/digestive system solid tumors, including but not limited to gastrointestinal tract, pancreatic, and colorectal cancers. Eligible participants will be randomized in a 1:1 ratio to receive Romiplostim N01 plus oral ATRA or Romiplostim N01 alone for 12 weeks, with follow-up through Week 24. The primary outcome is the overall platelet response rate at Week 12, defined as platelet count \>50 x 10\^9/L in at least 2 of the last 3 scheduled platelet assessments up to Week 12. Secondary outcomes include sustained response during Weeks 13 to 24, complete and partial response rates, duration of response, time to response, platelet count changes, platelet transfusion requirements, bleeding events, and safety.