Clinical Registration Study of Haplo-HSCT for Elderly Patients With Acute Leukemia/ Myelodysplastic Syndrome

Currently, the transplantation of allogeneic hematopoietic stem cells (allo-SCT) remains the main and often the only cure for neoplastic hematologic disorder or hematological malignancy. Although HLA-matched siblings are the preferred donor, not all patients have one; or it needs to wait so long to obtain it that the optimal time for transplantation is past. Haploidentical transplants as secondary donors are more readily available and may be considered in combination with the conditions of the donor and the patient and the experience of the transplant facility when a matched donor is unavailable. Currently, haploidentical transplantation has been commonly applied to young patients. On the other hand, TRM rate will be higher in elderly patients and patients with high comorbidity due to tolerability, thus reducing the ultimate benefits of patients.

The choice of conditioning regimen is influenced by multiple factors such as disease type, disease status, physical condition, and source of transplant donor. For patients over 55 years of age or with a comorbidity index ≥3, the RIC regimen may be considered to improve patient tolerability. RIC regimen can improve the tolerability of patients receive transplants, while regimens such as immune suppressants are also needed to control and improve the overall transplant efficiency. An in-depth study of RIC regimen will help improve the effects of transplantation and increase patient benefits.

This study is aim to evaluate the efficacy of RIC conditioning regimen for transplantation in elderly patients or patients with high comorbidity receiving the transplantation of haploidentical hematopoietic stem cells.

Drugs and dosage of conditioning regimen:

Ara-C(2g/m2/day,-10 days to -9 days),Bu(9.6mg/kg,-8 days to -6 days),Flu(30mg/m2/day,-6 days to -2 days),Cy(1,000mg/m2/day,-5 days to -4 days),semustine(250mg/m2,-3 days),ATG(10 mg/kg,-5 to -2 days).

Supportive care:

CsA: To prevent GVHD, CsA therapy starts 9 days before transplantation at 2.5 mg/kg intravenously until gut function returns to normal after transplantation; CsA is then orally administered. MMF: To prevent GVHD, 0.5g of MMF is orally administered every 12 hours 9 days before transplantation until hematopoietic function is restored after transplantation. MTX: To prevent GVHD, MTX is intravenously administered at 15 mg/m2 on day 1 after transplantation. On days 3, 6 and 11 after transplantation, MTX is intravenously administered at 10 mg/m2. Ganciclovir: To prevent post-transplantation CMV infection, it is administered 2 days before transplantation, and to prevent post-transplantation CMV infection, it is orally administered at 400 mg twice a day until the end of all immunosuppressive medications.

Primary endpoint is 1-year LFS. Secondary endpoints are 1-year OS and 1-year TRM, Other indicators to be assessed in this study include acute GVHD, chronic GVHD, CMV activation, EBV activation, engraftment.

CMV and EBV Tests are performed twice weekly for monitor based on PCR means.

The follow-up period designed for this study is 1 year, with the day of hematopoietic stem cell transplantation as Day 1 and the visit dates of Day 0, 1st month, 2nd month, 3rd month, 6th month and 12th month. The end of the study is defined as the date of the last visit of the last patient (LPLV).

• 1-year OS [Time frame: Participants will be followed for an expected average of 1 years]
• 1-year TRM [Time frame: Participants will be followed for an expected average of 1 years]