[The curative efficacy of unrelated umbilical cord blood stem cells transplantation in intensified myeloablative conditioned patients with acute lymphoblastic leukemia].

OBJECTIVE: To retrospectively analyze the efficacy of unrelated umbilical cord blood transplantation (UCBT) with intensified myeloablative conditioning regimen in patients with acute lymphoblastic leukemia (ALL).

METHODS: From September 2006 to December 2013, a total of 110 consecutive patients with ALL had received UCBT, including 79 male and 31 female patients with a median age of 14(2-51) years, a median weight of 45(12-100)kg. Sixty-one cases were in the first complete remission (CR), 30, 6 and 13 patients in the second, the third CR and advanced stages respectively. The conditioning regimen consisted of total body irradiation, cyclophosphamide and cytarabine (TBI/Cy/Ara-C) in 61 patients, busulfan, cyclophosphamide and fludarabine (BU/Cy/Flu) in 39 patients and BU/Cy/Ara-C in 10 patients. All patients received a combination of cyclosporine (CsA) and mycophenolate mofetil (MMF) for the prophylaxis of graft-versus-host disease (GVHD).

RESULTS: The median amount of total nuclear cells(TNC) and CD34(+) cells were 3.90(1.97-13.50)×10(7)/kg and 2.07(0.40-5.56)×10(5)/kg. The cumulative incidence of sustained donor engraftment was 94.5% (95% CI 94.5%-94.6%) at a median of 18 days after transplantation (range, 12-37 days). The cumulative incidence of platelet recovery at 180 days after transplantation was 82.1% (95% CI 81.8%-82.4%) with a median time to recovery of 40 (range, 15-153) days. Incidences of grade Ⅱ~Ⅳ and Ⅲ~Ⅳ acute GVHD were 21.8% and 10.9% respectively. The cumulative incidence of chronic GVHD was 17.9%. During a median follow up period of 26 (range 6-94) months, the disease free survival (DFS) and overall survival (OS) rates at 3 years were 54.5% and 58.8%, respectively. The transplantation-related mortality (TRM) at 180 days after transplantation was 22.7%. The cumulative incidence of 3-year relapse rate was 18.3% (95% CI 17.9%-18.6%).

CONCLUSIONS: UCBT with intensified myeloablative conditioning regimen not only improves the donor engraftment, but also shortens the interval of neutrophil and platelet recovery. It is a safe and effective option for children and adult ALL patients lack of matched related donors.