The Safety and Efficacy of GMDTC for Injection in Subjects With Elevated Cadmium Levels

The primary objective of this study is to evaluate the pharmacodynamic characteristics of GMDTC for Injection in subjects with elevated cadmium levels after administration, while the secondary objectives are to assess the safety, tolerability and pharmacokinetic profile of GMDTC for Injection following multiple-dose administration in the same population; based on the results from Phase I single- and multiple-dose studies, the initial dose group in this trial is set at 2000 mg with a concentration of 4 mg/mL, where the first 4 participants (including 3 in the treatment group and 1 in the placebo group) will be enrolled first, and subsequent participants in the same dose group can only continue enrollment after investigators complete the 72-hour post-dose safety and tolerability assessments and confirm favorable results, with the SMC meeting to determine subsequent study plans including but not limited to dose escalation, concentration adjustment or increased treatment duration after completion of observation for each dose group.

Inclusion criteria

Study participants must meet all of the following criteria to be enrolled in this trial:

• Voluntarily sign the informed consent form, aged between 18 and 70 years (inclusive), regardless of gender;
• Single morning urine cadmium >5 μg/g creatinine (with creatinine concentration ≥0.3 g/L and ≤3 g/L);
• eGFR ≥30 mL/min/1.73 m² (calculated using the CKD-EPI formula).

Exclusion criteria

Participants who meet any of the following criteria will be excluded from this study:

• Currently suffering from any clinically significant disease that, in the investigator's judgment, poses a safety risk for participation in this clinical trial;
• Patients with a history of kidney disease requiring hemodialysis;
• Patients with a history of severe infusion-related allergic reactions, known allergies to three or more substances, or known hypersensitivity to any component of this product (e.g., disodium edetate, mannitol);
• Previous diagnosis of diabetes with poorly controlled blood glucose;
• History of conditions predisposing to hypokalemia (e.g., periodic hypokalemia, primary aldosteronism);
• High-risk uncontrolled arrhythmia within the past 6 months, including:

• Resting atrial tachycardia with heart rate >100 bpm, 2) Significant ventricular arrhythmia (e.g., ventricular tachycardia), 3) High-grade atrioventricular block (e.g., Mobitz type II second-degree or third-degree AV block), 4) NYHA Class IV heart failure, 5) Left ventricular ejection fraction (LVEF) <50%; 7.Prolonged QT/QTc interval at screening/baseline (QTc: >450 ms in males, >470 ms in females) or known family history of long QT syndrome; 8. Use of any medication or supplement (e.g., SGLT2 inhibitors like dapagliflozin, canagliflozin, empagliflozin, etc.; GLUT2 inhibitors like cytochalasin B, phloretin, etc.) within 14 days prior to screening that may interact with the investigational drug; 9. Participation in any other clinical trial involving investigational drugs or medical devices within 3 months prior to screening; 10. Major surgery within 4 weeks before screening or planned surgery during the trial that may affect drug metabolism or safety assessment; 11. Blood donation or significant blood loss (≥200 mL, excluding menstrual bleeding), transfusion, or use of blood products within 1 month prior to screening; 12. Intolerance to venipuncture and/or history of syncope due to blood or needle exposure; 13. Pregnant or lactating women, or participants unwilling to use effective non-pharmacological contraception during the trial; 14. Inability to use contraception for 6 months after trial completion; 15.Inability to comply with dietary restrictions or nutritional guidelines; 16.Alcohol abuse or regular alcohol consumption (>14 units/week; 1 unit ≈ 200 mL beer [5%], 25 mL spirits [40%], or 85 mL wine [12%]) within 6 months before screening, or unwillingness to abstain from alcohol during the trial; 17. Participants with unstable psychiatric disorders, in the investigator's opinion, who cannot cooperate with the study; 18. Any other condition deemed by the investigator to compromise study compliance or safety.