Sequential regimen of clofarabine, cytosine arabinoside and reduced-intensity conditioned transplantation for primary refractory acute myeloid leukemia.

The prognosis of patients with acute myeloid leukemia in whom primary treatment fails remains very poor. In order to improve such patients' outcome, we conducted a phase 2, prospective, multicenter trial to test the feasibility of a new sequential regimen, combining a short course of intensive chemotherapy and a reduced intensity-conditioning regimen, before allogeneic stem-cell transplantation. Twenty-four patients (median age, 47 years) with acute myeloid leukemia in primary treatment failure were included. Cytogenetic risk was poor in 15 patients (62%) and intermediate in nine (38%). The sequential regimen consisted of clofarabine (30 mg/m2/day) and cytosine arabinoside (1 g/m2/day) for 5 days, followed, after a 3-day rest, by reduced-intensity conditioning and allogeneic stem-cell transplantation combining cyclophosphamide (60 mg/kg), intravenous busulfan (3.2 mg/kg/day) for 2 days and anti-thymocyte globulin (2.5 mg/kg/day) for 2 days. Patients in complete remission at day +120 received prophylactic donor lymphocyte infusion. Eighteen patients (75%) achieved complete remission. With a median follow-up of 24.6 months, the Kaplan-Meier estimate of overall survival was 54% (95% CI: 33-71) at 1 year and 38% (95% CI: 18-46) at 2 years. The Kaplan-Meier estimate of leukemia-free survival was 46% (95% CI: 26-64) at 1 year and 29% (95% CI: 13-48) at 2 years. The cumulative incidence of non-relapse mortality was 8% (95% CI: 1-24) at 1 year and 12% (95% CI: 3-19) at 2 years. Results from this phase 2 prospective multicenter trial endorsed the safety and efficacy of a clofarabine-based sequential reduced-toxicity conditioning regimen, which warrants further investigation. This study was registered at www.clinicaltrials.gov, identifier number: NCT01188174.

Reduced-toxicity conditioning with fludarabine, once-daily intravenous busulfan, and antithymocyte globulins prior to allogeneic stem cell transplantation: results of a multicenter prospective phase 2 trial.

BACKGROUND: The optimal intensity of myeloablation delivered as part of a reduced-intensity/toxicity conditioning (RIC/RTC) regimen to decrease the recurrence rate, without increasing nonrecurrence mortality (NRM), remains to be established. METHODS: The current phase 2, prospective, multicenter trial aimed to assess the efficacy and safety of an RIC/RTC regimen based on busulfan at a dose of 130 mg/m(2) /day intravenously for 3 days, fludarabine at a dose of 30 mg/m(2) /day for 5 days, and antithymocyte globulins at a dose of 2.5 mg/kg/day for 2 days. A total of 80 patients (median age, 53 years; range, 25-64 years) with hematological malignancies were included. RESULTS: With a median follow-up of 21 months (range, 12-36.5 months), the Kaplan-Meier estimates of overall and disease-free survival at 2 years were 62% (95% confidence interval [95% CI], 51%-73%) and 50% (95% CI, 33%-57%), respectively. The cumulative incidences of grade 2 to 4 acute graft-versus-host disease (GVHD) and chronic GVHD (all grades) were 29% (95% CI, 19%-39%) and 35% (95% CI, 24%-46%), respectively. At 2 years, the cumulative incidence of recurrence/disease progression and NRM were 44% (95% CI, 31%-56%) and 11% (95% CI, 6%-19%), respectively. Patient age, diagnosis, donor type, sex, presence of comorbidities, and the Hematopoietic cell transplantation-specific comorbidities index did not appear to have any statistically significant impact on NRM, recurrence/disease progression, disease-free survival, or overall survival. CONCLUSIONS: The RIC/RTC regimen used in the current study appeared to be safe, with a low NRM rate at 2 years noted among high-risk patients, and efficient disease control, warranting prospective phase 3 trials.