This trial is a single-arm, prospective clinical study aimed at evaluating the efficacy and safety of hetrombopag in preventing chemotherapy-induced thrombocytopenia (CIT) in patients with gastrointestinal tumors. The study plans to enroll 40 patients with gastrointestinal tumors who develop thrombocytopenia due to chemotherapy. Patients who meet the inclusion and exclusion criteria will maintain the same treatment regimen and dosage as the previous cycle (N-1 cycle). On the day of chemotherapy in the current cycle (N cycle), they will take hetrombopag (D1) at 7.5 mg/day orally for 14 consecutive days on an empty stomach, and may eat two hours after administration, avoiding taking it with meals.

Inclusion Criteria:

1. age ≥18 years;

2. pathologically confirmed gastrointestinal tumors (including esophageal cancer, gastric cancer, colorectal cancer, etc.);

3. during the previous chemotherapy cycle (N-1 cycle), patients had a minimum platelet count of ≥75×10⁹/L and at least one high-risk bleeding factor (① history of bleeding; ② previous treatment with platinum agents, gemcitabine, cytarabine, anthracyclines, etc.; ③ tumor cell bone marrow infiltration; ④ previous or ongoing radiotherapy, especially to long bones or flat bones such as the pelvis or sternum);

4. during the current chemotherapy cycle (N cycle), patients have a platelet count of ≥100±25×10⁹/L;

5. undergoing treatment cycles of 14 or 21 days and requiring at least one more cycle of therapy.

6. ECOG score: 0-2 points;

7. Adequate hematopoietic, liver, and kidney function:

   • Neutrophil count ≥ 1.5 x 10⁹/L
   • Hemoglobin ≥ 9.0 g/dL
   • Creatinine clearance ≥ 40 mL/min (Cockcroft-Gault formula)
   • For patients without liver metastasis, AST and ALT ≤ 2.5 times the upper limit of normal;
   • Bilirubin ≤ 2 times the upper limit of normal;
   • APTT and PT ≤ 1.5 times the upper limit of normal

8. Signed informed consent form.

Exclusion Criteria

1. Previous use of TPO-RA drugs;
2. Pre-treatment conditions that cause thrombocytopenia, such as hypersplenism or immune thrombocytopenia;
3. History of thrombosis;
4. Hematologic diseases (anemia, leukemia, autoimmune hemolytic diseases, etc.);
5. Major cardiovascular diseases (acute myocardial infarction, cerebral thrombosis, cerebral hemorrhage, etc.);
6. Pregnant or breastfeeding women;
7. Participation in other drug clinical trials within 4 weeks;
8. Poor compliance, unable to cooperate or report treatment responses;
9. Need for other antiplatelet or platelet-enhancing drugs, including traditional Chinese medicine and herbal preparations;
10. Use of prior platelet-stimulating drugs within 5 half-lives before first dose;
11. Platelet transfusion within 3 days before first dose.