Abstract
Background: Alternative donor hematopoietic cell transplantation (HCT) is an emerging topic in acute leukemia for patients without matched sibling donors (MSD) or unrelated donors (MUD). Cord blood transplantation (CBT) has been tried for several years in adult acute lymphoblastic leukemia (ALL), and the long-term survival outcomes were comparable to those treated with conventional donor HCT.
Aim : We have conducted double CBT (DCBT) in patients without both MSD and MUD for final step, and here, we report our phase 2 study results of clinical outcomes for adult ALL patients treated with DCBT.
Methods: During the period between 2005 and 2016, 67 patients (median age, 37 years [range, 16-59 years]; 34 Ph-negative ALL and 33 Ph-positive ALL) were treated with DCBT in CR1 (n=48), CR2 (n=15), and in advanced status (n=4). The indications for DCBT were unavailability of MSD and MUD, agreement for conduction of the transplantation procedure, and proper performance status and organ function to undertake transplantation. The median time to transplant was 198 days (range, 97-1751 days). All patients received DCBT following total body irradiation (TBI) 12.0 Gy plus cytarabine 9.0 g/m2 plus fludarabine 150 mg/m2, and graft versus host disease (GVHD) prophylaxis was attempted by administering tacrolimus plus mycophenolate mofetil. If residual leukemia was detected in the absence of GVHD at 3 months after transplantation, calcineurin inhibitors were rapidly discontinued.
Results: The median time for neutrophil and platelet recovery was 25 days (23 days [range, 12-109] for Ph-negative ALL and 26 days [range, 9-59] for Ph-positive ALL, P=0.336) and 34 days (27.5 days [range, 8-123] for Ph-negative ALL and 40 days [range, 9-185] for Ph-positive ALL, P=0.022), respectively. The median CD34+ cell count was 1.21 x 105/kg (range, 0.4-5.85) and TNC was 4.04 x 107/kg (range, 1.58-7.88). In our data, extramedullary involvements were more frequently observed in Ph-negative ALL, while hyperleukocytosis was frequently observed in Ph-positive ALL. Except for 5 patients who died in aplasia, 28 developed acute GVHD (grade II in 23 and grade III in 5), and the cumulative incidence of acute GVHD at 1-year was 41.8%, and the incidence was 9.0% for acute GVHD with grade III-IV. Except for 11 patients with early deaths within 100 days, 17 developed chronic GVHD (11 mild, 4 moderate, 2 severe), resulting in a 4-year cumulative incidence of 23.0% (3.0% for severe chronic GVHD). After a median follow-up duration of 43.7 months (range: 6.5 - 135.3), the 4-year cumulative incidence of relapse (CIR) and non-relapse mortality (NRM) were 15.6% and 29.6% (7.2% and 29.2% for CR1), respectively, and the 4-year disease-free survival (DFS) and overall survival (OS) rates were 52.5% and 53.9% (62.9% and 65.6% for CR1), respectively. The 4-year CIR, NRM and DFS for Ph-negative and Ph-positive subgroup was 9.6% and 21.6% (P=0.140), 21.0% and 38.9% (P=0.107), and 66.5% and 37.7% (P=0.017). The results of Ph-negative and Ph-positive subgroup in CR1 were 4.8% and 9.9% (P=0.357), 19.1% and 43.0% (P=0.088), and 76.1% and 45.0% (P=0.029), respectively. In multivariate analysis, advanced disease status≥CR2 (HR, 5.61; 95% CI, 1.4-22.2; P=0.014) was related with higher CIR rate, and older age (HR, 3.75; 95% CI, 1.5-9.3; P=0.004) and lower CD34+ cell count (HR, 4.96; 95% CI, 1.1-22.3; P=0.037) were related with higher NRM rates. Overall, Ph-chromosome (HR, 2.65; 95% CI, 1.2-5.8; P=0.016), longer time to transplant (HR, 4.18; 95% CI, 1.9-8.9; P <0.001), lower CD34+ cell count (HR, 3.66; 95% CI, 1.4-9.5; P=0.008) and the absence of acute GVHD (HR, 3.19; 95% CI, 1.4-7.4; P=0.006) were related to poorer DFS.
Conclusion: Our data showed that DCBT can be a good alternative choice for providing a long-term disease control for adult ALL patients especially in Ph-negative subgroup. Since Ph-positive subgroup was related with poorer DFS and higher NRM rate in our data, another alternative haploidentical HCT should be considered.
No relevant conflicts of interest to declare.
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