Trial to Assess the Efficacy of a TCR Alfa Beta Depleted Graft in Pediatric Affected by ALL or AML and Receiving an HSCT

Phase I/II Study of Allogeneic Hematopoietic Stem Cell Transplantation From an HLA-partially Matched Family Donor After TCR Alfa Beta Negative Selection in Pediatric Patients Affected by Hematological Disorders

Allocation: Non-Randomized Endpoint Classification: Safety/Feasibility Intervention Model: Single Group Assignment Masking: Open Label Primary Purpose: Treatment Study to assess the feasibility and safety of the infusion of a T cells receptor (TCR) alfa beta depleted graft in pediatric patients affected by malignant and non-malignant hematological disorders and receiving an Hematopoietic stem cell transplantation (HSCT) from a Human leukocyte antigen (HLA) partially matched family donor.

In this study the hypothesis is that the transplantation of Peripheral blood stem cells (PBSC)selectively depleted of TCR alfa beta T lymphocytes would offers some advantages over the use of positively selected CD34+ stem cells because of the presence of other non-stem ancillary cells (in particular Natural killer (NK) and alfa beta T cells) that might have potential positive effects on the outcome of the transplant.

The clinical relevance of NK-cell alloreactivity has been demonstrated in adult patients affected by Acute myeloid leukemia (AML) and given T-cell depleted HSCT from an HLA-disparate relative where a subgroup of patients had a particularly low risk of leukemia relapse. These patients belonged to the group transplanted from a donor having NK cells that were alloreactive towards recipient targets i.e. the patient cells express HLA-class I alleles that do not share the inhibiting allelic determinants recognized by Killer immunoglobulin-like receptors (KIR) on donor NK cells. The emergence of this concept of NK-cell alloreactivity has represented a sort of revolution in the field of Haplo-identical hematopoietic stem cell translantation (haplo-HSCT), as the presence of alloreactive NK cells has been shown to positively affect the outcome of transplantation in adults and to display a Graft versus leukemia (GvL) effect that can compensate for the lack of T-specific anti-tumor effect.

The purpose of this study is to evaluate the feasibility and safety of the selective infusion of TCR alfa beta T cell depleted graft in pediatric patients affected by malignant or non malignant hematological disorders and receiving an HSCT from a partially matched family donor.

This study will provide new data on the feasibility and the safety of using a TCR alfa beta T cell depleted graft instead of fully T cell depleted graft to improve the outcome of patients receiving a haplo-HSCT for the treatment of hematological disorders.

Inclusion Criteria:

• Patients aged ≥ 3 months and < 21 years
• Patients diagnosed with malignant hemopathies (Acute Lymphoblastic leukemia (ALL), Acute Myeloid Leukemia (AML), Non-Hodgkin Lymphoma (NHL)) in complete morphological remission or Myelodysplastic Syndromes (MDS), Solid Tumors or non malignant hematological disorders (SCID, Acquired and Congenital Aplastic Anemia, other Primary Immunodeficiencies, Life-threatening Cytopenia) eligible for an allogeneic transplantation and lacking a related or unrelated HLA-matched donor
• Patients displaying an HLA-partially matched family donor
• Lansky/Karnofsky score > 40, WHO > 4
• Signed written informed consent

Exclusion Criteria:

• Grade >II acute GvHD or chronic extensive GvHD at the time of inclusion
• Patient receiving an immunosuppressive treatment for GvHD treatment at the time of inclusion
• Dysfunction of liver (ALT/AST > 5 times normal value, or bilirubin > 3 times normal value), or of renal function (creatinine clearance < 30 ml / min)
• Severe cardiovascular disease (arrhythmias requiring chronic treatment, congestive heart failure or left ventricular ejection fraction <40%)
• Current active infectious disease (including positive HIV serology or viral RNA)
• Serious concurrent uncontrolled medical disorder
• Pregnant or breast feeding female patient
• Lack of parents' informed consent.