Targeted Dose Study of ATG in Haploidentical Hematopoietic Stem Cell Transplantation

Chinese PLA General Hospital (301 Hospital)

Status and phase: Completed; Phase 3

Conditions: Haploidentical Hematopoietic Stem Cell Transplantation

Treatments: Drug: Individual Antithymocyte globulin; Drug: Antithymocyte globulin

Study type: Interventional

Funder types: Other

Identifiers

NCT05166967

S2020-484-02

Details and patient eligibility

About

The purpose of this study is to determine the response and toxicity rate of two different dosages (Individualized dosage VS. fixed dosage) of ATG as a prophylaxis for acute GVHD in haploidentical peripheral blood stem cell transplantation (haplo-PBSCT).

Full description

Acute graft-versus-host disease (aGvHD) is an important complication of haploHSCT. The Seattle group initially introduced the use of ATG as a treatment for acute graft-versus-host disease (aGVHD) in allogeneic hematopoietic stem cell transplantation (haplo-PBSCT) recipients. Presently, in both myeloablative and reduced-intensity conditioning (RIC) haplo-PBSCT, ATG is part of post engraftment immunosuppressive regimens. The regimens for prophylaxis of GVHD based on 10mg/kg rabbit anti-human thymocyte immunoglobin (ATG, Thymoglobin®, Genzyme Polyclonals S.A.S) effectively reduced the occurrence of grade II-IV aGvHD. Howevre, the incidence of cytomegalovirus (CMV) and EB virus (EBV) reactivation were higher due to a slower immune reconstitution. The 100-day cumulative incidence of CMV and EBV viremia were both over 70% in our unmanipulated haplo-PBSCT program. The optimal dose of ATG balancing the efficacy of GVHD prophylaxis and the risk of virus reactivation in haplo-PBSCT remains unknown.

Reports on the pharmacokinetics of Thymoglobulin in allo-HSCT revealed a high variability. Recent pharmacokinetic studies have shown that the half-life of total ATG after transplant is longer than the active ATG (which is available to bind to human lymphocytes and causes the desired immunological effects). And active ATG appears more associated with pharmacodynamics effects. In our previous cohort study, we found that virus reactivation and acute GVHD were highly affected by ATG exposure (area under the curve, AUC). We have found an optimal range of active ATG range is 110-148.5UE/ml.day the efficacy of GVHD prophylaxis and the risk of virus reactivation. The cumulative incidence of CMV reactivation and persistent CMV hyperemia at 180 days after transplantation in the optimal total AUC group was 60.57% and 31.52% respectively. Significantly lower than 77.08% and 56.25% in the non-optimal total AUC group.

The results suggested that Individualized dosing of ATG has a potential advantage in balancing the efficacy of GVHD prophylaxis and the risk of virus reactivation in haplo-PBSCT. This may improve the survival and quality of life of patients undergoing haplo-PBSCT. A prospective randomized trial is required to compare the efficacy of Individualized dosage of ATG as a prophylaxis for acute GVHD in haplo-PBSCT.

Enrollment: 204 patients

Sex: All

Ages: 14 to 65 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• 1. All patients should have the indication of Haploidentical hematopoietic stem cell transplant.
• 2. All patients should sign an informed consent document indicating that they understand the purpose of and procedures required for the study and be willing to participate in the study.

Exclusion criteria

1.Patients with any conditions not suitable for the trial (investigators' decision).

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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204 participants in 2 patient groups

Individual dose of ATG

Experimental group

Description:

Individual dose of ATG: Individual dose of ATG was Intravenous infused every day from day -5 to day -2 (total ATG dose was calculated based on pharmacokinetic index, within a range of 6 mg/kg to 13mg/kg), and the active ATG concentration ranges from 110 to 148.5UE/ml.

Treatment:

Drug: Individual Antithymocyte globulin

Fixed dose of ATG

Active Comparator group

Description:

A total amount of 10mg/kg ATG was divided into 4 days (from day -5 to day -2). The specific usage: 1.5mg/kg for day -5, 2.5mg/kg for day -4 and day -3, 3.5 mg/kg for day -2.

Treatment:

Drug: Antithymocyte globulin