Assessment of the Dose Safety and Efficacy of Serine Combined With Fluorouracil Drugs

Exclusion Criteria

• •1. Trial Participation Restrictions: Currently participating in or having received investigational drug/device treatment within the past 4 weeks;
• •2. Prior Fluorouracil-Based Therapy Restrictions: History of ≥Grade 3 toxicity (e.g., myelosuppression, gastrointestinal toxicity) following prior fluorouracil-based therapy, deemed unsuitable for re-administration by the investigator;
• •3. Recent Surgery Restriction: Undergone major surgery (excluding diagnostic biopsy) within 28 days prior to first dosing, or scheduled for surgery during the study period;
• •4. Metabolic and Nutritional Status Restriction: Presence of severe malnutrition (BMI \< 18.5 or serum albumin \< 30 g/L), or inability to supplement serine orally (e.g., malabsorption syndrome, short bowel syndrome); Known serine metabolism disorders (e.g., PHGDH/PSAT1 gene mutation-related diseases);
• •5. Concurrent severe disease restrictions: Severe cardiovascular disease (NYHA Class III/IV heart failure, myocardial infarction within 6 months, uncontrolled hypertension \>150/100 mmHg); severe respiratory disease (COPD, GOLD Stage ≥3, interstitial lung disease); Active infection (requiring systemic antibiotic/antiviral therapy);
• •6. Active HIV/viral hepatitis: HIV-positive status, or active hepatitis B (HBV-DNA ≥ 2000 IU/mL), or active hepatitis C (HCV-RNA positive); (Note: Patients with HBV-DNA \< 2000 IU/mL receiving antiviral therapy may be enrolled);
• •7. Neurological disorders: Uncontrolled brain metastases (with intracranial hypertension or neurological symptoms), or history of severe psychiatric illness/substance abuse (impeding treatment compliance);
• •8. Allergy history: Known allergy to fluorouracil-based drugs or serine supplements;
• •9. Pregnancy/lactation: Pregnant or lactating women (patients of childbearing potential must use highly effective contraception);
• •10. Other conditions deemed ineligible by the investigator: Any concomitant conditions or laboratory abnormalities that may interfere with study results, increase risk, or compromise patient safety.