A Phase 1/2 interventional study of Treatment Plan 1: Stratum 1 and Treatment Plan 2: Strata 2, 3, or 4 in Metabolic Disorders, Hematologic, Immune, or Bone Marrow Disorders and Hemoglobinopathies, sponsored by Washington University School of Medicine. Recruiting at 28 sites in 2 countries. Open to participants aged Up to 20 Years. Per ClinicalTrials.gov, last updated 2026-09-16.
Sponsored by Washington University School of Medicine · Phase 1/2, Interventional, and Treatment
The hypothesis for this study is that a preparative regimen that maximizes host immunosuppression without myeloablation will be well tolerated and sufficient for engraftment of donor hematopoietic cells. It is also to determine major toxicities from these conditioning regimens, within the first 100 days after transplantation.
The study uses reduced intensity conditioning that is immune suppressive to achieve donor cell engraftment without exposure to radiation or high dose chemotherapy in children with non-malignant disorders. The intent is to minimize early and late regimen related toxicities in the context of a reduced intensity regimen.
In addition to maximizing opportunity for donor cell engraftment, the trial seeks to minimize toxicities associated with transplant such as graft versus host disease and employs GVHD prophylaxis that seeks to decrease rates of acute and chronic GVHD in the setting of matched and mismatched donor stem cell transplants from marrow and cord blood sources.
Stratum 1: Patient must have non-malignant disorder, excluding thalassemia. Must be receiving a 8/8 HLA-matched bone marrow, related or unrelated Stratum 2: Patient must have thalassemia receiving 8/8 HLA-matched bone marrow or 5-8/8 HLA-matched UCB. Related or unrelated.
Stratum 3: Patient must have a hemoglobinopathy receiving 7/8 HLA-matched bone marrow or 5-8/8 HLA-matched UCB. Related or unrelated.
Stratum 4: Patient must have a non-malignant disorder (excluding hemoglobinopathy) receiving 7/8 HLA-matched bone marrow or 5-8/8 HLA-matched UCB. Related or unrelated.
All strata:
Exclusion Criteria:
Recipients with non-malignant disorders, excluding thalassemia. Related or unrelated 8/8 HLA-matched bone marrow
Drug: Treatment Plan 1: Stratum 1 · Drug: GVHD Regimen B: BM Recipients
Recipient with transfusion dependent thalassemia. Related or unrelated. 8/8 HLA-matched bone marrow or 5-8/8 HLA-matched UCB
Drug: Treatment Plan 2: Strata 2, 3, or 4 · Drug: GVHD Regimen A: UCB Recipients · Drug: GVHD Regimen B: BM Recipients
Recipient with hemoglobinopathy Related or unrelated. 7/8 HLA-matched bone marrow or 5-8/8 HLA-matched UCB
Drug: Treatment Plan 2: Strata 2, 3, or 4 · Drug: GVHD Regimen A: UCB Recipients · Drug: GVHD Regimen B: BM Recipients
Recipient with non-malignant disorder, excluding hemoglobinopathy Related or unrelated. 7/8 HLA-matched bone marrow or 5-8/8 HLA-matched UCB
Drug: Treatment Plan 2: Strata 2, 3, or 4 · Drug: GVHD Regimen A: UCB Recipients · Drug: GVHD Regimen B: BM Recipients
Day -50 to -21: Hydroxyurea 30mg/kg PO q day Day -22: Campath-1H 3 mg IV or SQ... Day -21: Campath-1H 10 mg IV or SQ... Day -20: Campath-1H 15 mg IV or SQ... Day -19: Campath-1H 20 mg IV or SQ... Day -8: Fludarabine 30mg/m2 IV... Day -7: Fludarabine 30mg/m2 IV... Day -6: Fludarabine 30mg/m2 IV... Day -5: Fludarabine 30mg/m2 IV... Day -4: Fludarabine 30mg/m2 IV... Day -3: Melphalan 140 mg/m2 IV... (dose modifications for patients \<10 kgs) Procedure/Surgery: Hematopoietic stem cell infusion on Day 0...
Day -50 to -21: Hydroxyurea 30mg/kg PO q day… Day -22: Campath-1H 3 mg IV or SQ... Day -21: Campath-1H 10 mg IV or SQ... Day -20: Campath-1H 15 mg IV or SQ... Day -19: Campath-1H 20 mg IV or SQ... Day -8: Fludarabine 30mg/m2 IV... Day -7: Fludarabine 30mg/m2 IV... Day -6: Fludarabine 30mg/m2 IV... Day -5: Fludarabine 30mg/m2 IV... Day -4: Fludarabine 30mg/m2 IV... Day -4: Thiotepa 8mg/kg IV… Day -3: Melphalan 140 mg/m2 IV... (dose modifications for patients \<10 kgs) Procedure/Surgery: Hematopoietic stem cell infusion on day 0...
Day -3: Begin Tacrolimus or cyclosporine Begin MMF Day -1: Abatacept 10mg/kg IV Day +5: Abatacept 10mg/kg IV Day +14: Abatacept 10mg/kg IV Day +28: Abatacept 10mg/kg IV Day +60: Abatacept 10mg/kg IV Day +100: Abatacept 10mg/kg IV
Day -3: Begin Tacrolimus or cyclosporine Begin MMF Day -1: Abatacept 10mg/kg IV Day +1: Methotrexate 7.5mg/m2 IV Day +3: Methotrexate 7.5mg/m2 IV Day +5: Abatacept 10mg/kg IV Day +6: Methotrexate 7.5mg/m2 IV Day +14: Abatacept 10mg/kg IV Day +28: Abatacept 10mg/kg IV Day +60: Abatacept 10mg/kg IV Day +100: Abatacept 10mg/kg IV Day +180: Abatacept 10mg/kg IV Day +270: Abatacept 10mg/kg IV Day +365: Abatacept 10mg/kg IV
Donor engraftment as measured by chimerism
Engraftment is measured in myeloid and lymphoid lineage cells
Time frame: 100 days post-transplant
Major toxicities as graded by the CTC v4
Toxicity monitoring includes unanticipated side effects (new) and all severe irreversible toxicities Grade 3 and above unexpected Grade 4 and above - all toxicities that are possibly, probably or definitely related to protocol therapy All deaths irrespective of attribution
Time frame: 100 days post-transplant
Time to neutrophil and platelet engraftment as measured by complete blood counts
Defined as an ANC \>500/microliter and platelets \>20,000 or 50,000/microliter depending on disorder
Time frame: Post transplant
Incidence of acute graft-versus-host disease as measured by protocol grading scale
aGVHD - involving the skin, gut and liver. Classified according to grading described by Thomas et al. NEJM 1975; 292:895-902
Time frame: 100 days post-transplant
Incidence of chronic graft-versus-host disease as measured by protocol grading scale
cGVHD classified per Schulman et al. Am J Med 69: 204-17, 1980.
Time frame: 2 years post-transplant
Long-term donor engraftment by donor chimerism
Donor chimerism is determined by PCR analysis after cell separation into lymphoid and myeloid lineage cells using antibodies. Can also be detected by FISH analysis in the event of donor and recipient sex discrepancy.
Time frame: 2 years post-transplant
Immune reconstitution by laboratory evaluations
Immune reconstitution detected by absolute numbers of T cell phenotypes, B cells and NK cells. T cell function determined by proliferative response to mitogens. B cell function determined by evaluating anti-tetanus antibody titers.
Time frame: 1 year post-transplant
Overall and disease free survival
Overall survival is defined as survival with or without disease Event free survival is defined as disease free, severe GVHD free survival, monitoring quality of life and relevant parameters.
Time frame: 2 years post-transplant
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Washington University School of Medicine