Allogeneic Hematopoietic Stem Cell Transplantation after Combination Therapy with Imatinib and Intensive Chemotherapy for Newly Diagnosed Philadelphia Chromosome Positive (Ph⁺) Acute Lymphoblastic Leukemia.

[Background] In JALSG Ph ⁺ ALL protocol(IDEAMOP) study, combination therapy with conventional intensive chemotherapy with imatinib (600mg/day) provided high quality of hematologic and cytogenetic (94%) and molecular (77%) complete remission (CR) for the patients with newly diagnosed Ph ⁺ ALL(

[Patients and Methods] Those three newly diagnosed Ph ⁺ ALL patients (M/F:2/1 Age:30,31,38 y.o.) were treated with IDEAMOP between Jan 28,2003 and Feb 13,2004. All patients attained CR after single course of induction therapy and median time of CR was 21 (19–27) days. During consolidation therapies, two of them found HLA-matched unrelated donors and one patient chose to receive cord blood transplantation. As conditioning regimen for allo-HSCT, all of them received total body irradiation, high-dose cyclophosphamide and high-dose etoposide before allo-SCT.

[Results] Allo-HSCT was undergoing during their first CR(CR1). Regimen related toxicity and complications of the transplantation were well tolerated. The reconstitutions of bone marrow function were similar to other patients with Ph-negative ALL treated by allo-HSCT. Although two patients presented with either limited or extensive chronic GvHD, they were clinically controlled with or without steroid. Minimal residual disease (MRD), measured by RQ-PCR assay, was detected in two of three patients before allo-HSCT. However, MRD was not detected in any of the patients after allo-HSCT. All of three patients remain in CR at a median follow-up time of 25 (18–31) months.

[Conclusion] Although the number of patients are small, imatinib (600mg/day) with intensive chemotherapy as remission induction for newly diagnosed Ph ⁺ ALL may have benefit for rapid control of disease, and may provide better outcome of allo-HSCT without additional severe toxicities.