Randomized Study of ATG for Graft Versus Host Disease (GVHD) Prevention in Paediatric Patients Given an Unrelated Donor Stem Cell Transplantation

Paediatric patients affected by haematological malignancies and eligible to undergo HSCT from an unrelated volunteer will be stratified according to the degree of compatibility with their donor, the source of haematopoietic stem cells employed (BM vs. PB) and the disease phase (good vs. poor prognosis). In particular, on the basis of compatibility with their donor, patients will be allocated to 2 different arms: those transplanted from an unrelated donor either perfectly matched or with a single allelic disparity at one of the HLA loci (i.e. A, B, C, and DrB1) vs. those transplanted from an unrelated donor either with 2 allelic disparities or with an antigenic disparity at the HLA loci (i.e. A, B, C, and DrB1). Patients enrolled in the study will be randomized to receive ATG (Fresenius) at a dosage of either 30 mg/Kg (10 mg/Kg on days -4, -3 and -2) or 15 mg/Kg (5 mg/Kg on days -4, -3 and -2). Good prognosis patients are defined as follows: ALL in 1st CR; ALL in 2nd CR belonging to S2 group; AML in 1st CR, AML in 2nd CR and relapsed more than 6 months after stopping therapy; NHL in 2nd CR; Ph+ CML in 1st CP; refractory cytopenia. Poor prognosis patients are defined as follows: ALL in 2nd CR belonging to the S3-S4 group; ALL in ≥ 3rd CR; AML in 2nd CR and relapsed less than 6 months after stop therapy; secondary AML; NHL in 3rd CR; Ph+ CML in 2nd CP, as well as in AP; RAEB, RAEB-t, JMML.