This is a prospetive,Single-Center, Single-Arm, Phase IIB Clinical Study.This study aims to evaluate the efficacy and safety of dose-attenuated IST combined with Hetrombopag in elderly patients (≥65 years) with VSAA/SAA.

Design : Prospective, single-center, single-arm, open-label Phase IIB trial.

Intervention :

P-ATG : 15 mg/kg/day IV ×5 days. Cyclosporine : 3 mg/kg/day (adjusted to trough 100-200 μg/L). Hetrombopag : 15 mg daily. Follow-Up : Weekly for 24 weeks, with bone marrow evaluation at 24 weeks.

Inclusion Criteria :

Confirmed diagnosis of VSAA/SAA. Age ≥65 years. Completion of all screening assessments. Ability to swallow oral medication. Signed informed consent (by patient or legal guardian if patient is incapacitated).

Exclusion Criteria :

Clonal cytogenetic abnormalities (excluding isolated -Y or +8). Prior treatment with ATG/high-dose cyclophosphamide. Prior cyclosporine/tacrolimus use >12 months. Prior TPO-RA therapy >3 months. Uncontrolled malignancies or conditions contraindicating ATG. Severe organ dysfunction (e.g., creatinine ≥177 μmol/L). Investigator judgment of unsuitability.

Inclusion Criteria:

• Clinical diagnosis of VSAA/SAA.
• Age ≥65 years.
• Completion of all screening assessments.
• Must be able to swallow tablets.
• Signed informed consent (by patient or legal guardian if patient is incapacitated).

Exclusion Criteria:

• Clonal cytogenetic abnormalities (excluding isolated -Y or +8).
• Prior treatment with ATG/high-dose cyclophosphamide.
• Prior cyclosporine/tacrolimus use >12 months.
• Prior TPO-RA therapy >3 months.
• Uncontrolled malignancies or conditions contraindicating ATG.
• Severe organ dysfunction (e.g., creatinine ≥177 μmol/L).
• Investigator judgment of unsuitability.