High curability via intensive reinduction chemotherapy and stem cell transplantation in young adults with relapsed acute lymphoblastic leukemia in Sweden 2003-2007.

BACKGROUND A minority of patients with adult acute lymphoblastic leukemia who relapse are rescued. The aim of this population-based study was to assess the results of reinduction treatment and allogeneic stem cell transplantation in patients in second complete remission. DESIGN AND METHODS Between 2003-2007, 76 adults (<66 years) with relapsed acute lymphoblastic leukemia (Burkitt's leukemia excluded) were prospectively reported to The Swedish Adult Acute Leukemia Registry and later evaluated. RESULTS Reinduction with: (i) mitoxantrone, etoposide, and cytarabine (MEA); (ii) fludarabine, cytarabine, pegylated-asparaginase plus granulocyte colony-stimulating factor (FLAG-Asp); and (iii) cytarabine, betamethasone, cyclophosphamide, daunorubicin, and vincristine (ABCDV) resulted in complete remission in 6/9 (67%), 10/16 (63%) and 9/21 (43%) of the patients, respectively. Allogeneic stem cell transplantation was performed during second complete remission in 29 patients. Multivariate analysis regarding overall survival after relapse revealed that age over 35 years at diagnosis and relapse within 18 months were negative prognostic factors. Overall survival rates at 3 and 5 years were 22% (95% CI: 13-32) and 15% (95% CI: 7-24). Of 19 patients less than 35 years at diagnosis who underwent allogeneic stem cell transplantation in second remission, ten (53%) are still alive at a median of 5.5 years (range, 4.2-8.3) after relapse, whereas all patients over 35 years old at diagnosis have died. CONCLUSIONS Allogeneic stem cell transplantation remains the treatment of choice for young adults with relapsed acute lymphoblastic leukemia. Both (i) mitoxantrone, etoposide, and cytarabine and (ii) fludarabine, cytarabine, pegylated-asparaginase plus granulocyte colony-stimulating factor seem effective as reinduction treatments and should be further evaluated. New salvage strategies are needed, especially for patients over 35 years old at diagnosis.