Results:
Patients: Patient characteristics are summarised in Table 1. A cohort of eight pediatric patients with primary refractory or multiply-relapsed acute leukemia was analysed. The median age was 8,5 years (range 1 year – 18 years). Three patients had a primary refractory leukemia, including two patients with an acute lymphoblastic leukemia and one patient with an acute biphenotypic leukemia. Five patients had a multiply-relapsed leukemia, including 2 patients with an acute myeloid leukemia, two patients with an acute B-cell precursor lymphoblastic leukemia and one patient with an acute T-lymphoblastic lymphoma. 75 % of the patients had a high risk cytogenetic constellation. All patients had received ≥ three regimens of chemotherapy before the melphalan / cytarabine therapy and four patients (50%) had received a prior allogeneic HSCT before the melphalan / cytarabine therapy. All patients had documented BM - involvement prior to the salvage therapy melphalan / cytarabine. Response was evaluated in BM before and after melphalan and cytarabine. In three of the eight cases (38%) only a remission in peripheral blood was documented between the salvage therapy and the allogeneic HSCT and a bone marrow puncture was performed after the HSCT. The aim of this practice was to minimize the amount of invasive procedures in order to reduce the pain and psychological stress in the children.