Clofarabine Plus Busulfan is an Effective Conditioning Regimen for Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Acute Lymphoblastic Leukemia: Long-Term Study Results.

We investigated the long-term safety and disease control data obtained with i.v. busulfan (Bu) combined with clofarabine (Clo) in patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic stem cell transplantation (HSCT). A total of 107 patients, median age 38 years (range, 19 to 64 years) received a matched sibling donor (n = 52) or matched unrelated donor (n = 55) transplant for ALL in first complete remission (n = 62), second complete remission (n = 28), or more advanced disease (n = 17). Nearly one-half of the patients had a high-risk cytogenetic profile as defined by the presence of t(9;22) (n = 34), t(4;11) (n = 4), or complex cytogenetics (n = 7). Clo 40 mg/m2 was given once daily, with each dose followed by pharmacokinetically dosed Bu infused over 3 hours daily for 4 days, followed by hematopoietic cell infusion after 2 days of rest. The Bu dose was based on the drug clearance as determined by a test Bu dose of 32 mg/m2. The target daily area under the curve was 5500 µmol/min for patients aged <60 years and 4000 µmol/min for patients aged >59 years. With a median follow-up of 3.3 years among surviving patients (range, 1 to 5.8 years), the 2-year progression-free survival (PFS) for patients undergoing HSCT in first complete remission (CR1), second complete remission (CR2), or more advanced disease was 62%, 34%, and 35%, respectively. The regimen was well tolerated, with nonrelapse mortality (NRM) of 10% at 100 days and 31% at 2 years post-HSCT. The incidence of grade II-IV and III-IV acute graft-versus-host disease (GVHD) was 35% and 10%, respectively; 18% patients developed extensive chronic GVHD. The 2-year overall survival (OS) for patients undergoing HSCT in CR1, CR2, or more advanced disease was 70%, 57%, and 35%, respectively. Among 11 patients aged >59 years treated with reduced-dose Bu in CR1 (n = 7) or CR2 (n = 4), 4 remain alive and disease-free, with a median follow-up of 2.6 years (range, 2 to 4.7 years). Only the presence of minimal residual disease at the time of transplantation was associated with significantly worse PFS and OS in multivariate analysis. Our data indicate that the Clo-Bu combination provides effective disease control while maintaining a favorable safety profile. OS and NRM rates compare favorably with those for traditional myeloablative total body irradiation-based conditioning regimens.

Kebriaei P ，Bassett R ，Lyons G ，Valdez B ，Ledesma C ，Rondon G ，Oran B ，Ciurea S ，Alousi A ，Popat U ，Patel K ，Ahmed S ，Olson A ，Bashir Q ，Shah N ，Jones R ，Marin D ，Rezvani K ，Nieto Y ，Khouri I ，Qazilbash M ，Hosing C ，Shpall E ，Champlin RE ，Andersson BS ... -  《-》

Clofarabine combined with busulfan provides excellent disease control in adult patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation.

We investigated the safety and early disease control data for i.v. busulfan (Bu) in combination with clofarabine (Clo) in patients with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation (SCT). Fifty-one patients (median age, 36 years; range, 20-64 years) received a matched sibling (n = 24), syngeneic (n = 2), or matched unrelated donor transplant (n = 25) for acute lymphoblastic leukemia in first complete remission (n = 30), second complete remission (n = 13), or active disease (n = 8). More than one-half of the patients had a high-risk cytogenetic profile, as defined by the presence of t(9;22) (n = 17), t(4;11) (n = 3), or complex cytogenetics (n = 7). Clo 40 mg/m(2) was given once daily, with each dose followed by pharmacokinetically dosed Bu infused over 3 hours daily for 4 days, followed by hematopoietic SCT 2 days later. The Bu dose was based on drug clearance, as determined by the patient's response to a 32-mg/m(2) Bu test dose given 48 hours before the high-dose regimen. The target daily area under the receiver-operating characteristic curve was 5500 μM/min for patients age <60 years and 4000 μM/min for those age ≥60 years. The regimen was well tolerated, with a 100-day nonrelapse mortality rate of 6%. With a median follow-up of 14 months among surviving patients (range, 6-28 months), the 1-year overall survival, disease-free survival, and nonrelapse mortality rates were 67% (95% confidence interval [CI], 55%-83%), 54% (95% CI, 41%-71%), and 32% (95% CI, 16%-45%), respectively. For patients undergoing SCT in first remission, these respective rates were 74%, 64%, and 25%. Our data indicate that the combination of Clo and Bu provides effective disease control while maintaining a favorable safety profile.

Kebriaei P ，Basset R ，Ledesma C ，Ciurea S ，Parmar S ，Shpall EJ ，Hosing C ，Khouri I ，Qazilbash M ，Popat U ，Alousi A ，Nieto Y ，Jones RB ，de Lima M ，Champlin RE ，Andersson BS ... -  《-》

Clofarabine ± fludarabine with once daily i.v. busulfan as pretransplant conditioning therapy for advanced myeloid leukemia and MDS.

Although a combination of i.v. busulfan (Bu) and fludarabine (Flu) is a safe, reduced-toxicity conditioning program for acute myelogenous leukemia/myelodysplastic syndromes (AML/MDS), recurrent leukemia posttransplantation remains a problem. To enhance the conditioning regimen's antileukemic effect, we decided to supplant Flu with clofarabine (Clo), and assayed the interactions of these nucleoside analogs alone and in combination with Bu in Bu-resistant human cell lines in vitro. We found pronounced synergy between each nucleoside and the alkylator but even more enhanced cytotoxic synergy when the nucleoside analogs were combined prior to exposing the cells to Bu. We then designed a 4-arm clinical trial in patients with myeloid leukemia undergoing allogeneic stem cell transplantation (allo-SCT). Patients were adaptively randomized as follows: Arm I-Clo:Flu 10:30 mg/m(2), Arm II-20:20 mg/m(2), Arm III-30:10 mg/m(2), and Arm IV-single-agent Clo at 40 mg/m(2). The nucleoside analog(s) were/was infused over 1 hour once daily for 4 days, followed on each day by Bu, infused over 3 hours to a pharmacokinetically targeted daily area under the curve (AUC) of 6000 μMol-min ± 10%. Fifty-one patients have been enrolled with a minimum follow-up exceeding 100 days. There were 32 males and 19 females, with a median age of 45 years (range: 6-59). Nine patients had chronic myeloid leukemia (CML) (BC: 2, second AP: 3, and tyrosine-kinase inhibitor refractory first chronic phase [CP]: 4). Forty-two patients had AML: 14 were induction failures, 8 in first chemotherapy-refractory relapse, 7 in untreated relapse, 3 in second or subsequent relapse, 4 were in second complete remission (CR), and 3 in second CR without platelet recovery (CRp), 2 were in high-risk CR1. Finally, 1 patient was in first CRp. Graft-versus-host disease (GVHD) prophylaxis was tacrolimus and mini-methorexate (MTX), and those who had an unrelated or 1 antigen-mismatched donor received low-dose rabbit-ATG (Thymoglobulin™). All patients engrafted. Forty-one patients had active leukemia at the time of transplant, and 35 achieved CR (85%). Twenty of the 42 AML patients and 5 of 9 CML patients are alive with a projected median overall survival (OS) of 23 months. Marrow and blood (T cell) chimerism studies at day +100 revealed that both in the lower-dose Clo groups (groups 1+2) and the higher-dose Clo groups (groups 3+4), the patients had a median of 100% donor (T cell)-derived DNA. There has been no secondary graft failure. In the first 100 days, 1 patient died of pneumonia, and 1 of liver GVHD. We conclude that (1) Clo ± Flu with i.v. Bu as pretransplant conditioning is safe in high-risk myeloid leukemia patients; (2) clofarabine is sufficiently immunosuppressive to support allo-SCT in myeloid leukemia; and (3) the median OS of 23 months in this high-risk patient population is encouraging. Additional studies to evaluate the antileukemic efficacy of Clo ± Flu with i.v. Bu as pretransplant conditioning therapy are warranted.

Andersson BS ，Valdez BC ，de Lima M ，Wang X ，Thall PF ，Worth LL ，Popat U ，Madden T ，Hosing C ，Alousi A ，Rondon G ，Kebriaei P ，Shpall EJ ，Jones RB ，Champlin RE ... -  《-》

Phase II Trial of Reduced-Intensity Busulfan/Clofarabine Conditioning with Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Acute Myeloid Leukemia, Myelodysplastic Syndromes, and Acute Lymphoid Leukemia.

Clofarabine has potent antileukemia activity and its inclusion in reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (HSCT) for acute leukemia could potentially improve outcomes. We conducted a phase II study of busulfan (.8 mg/kg i.v. twice daily on days -5, -4, -3, and -2) with clofarabine (40 mg/m(2) i.v. daily on days -5, -4, -3, and -2) conditioning before allogeneic 8/8 HLA-matched related or unrelated HSCT. The primary endpoint was donor neutrophil engraftment by day +40. Secondary endpoints included nonrelapse mortality (NRM), acute and chronic graft-versus-host disease (GVHD), progression-free survival (PFS), and overall survival (OS). Thirty-four patients (acute myeloid leukemia [AML], n = 25; myelodysplastic syndromes, n = 5; and acute lymphoid leukemia, n = 4) were enrolled. Day 40+ engraftment with donor chimerism was achieved in 33 of 34 patients with 1 patient dying before count recovery. Day 100 and 1-year NRM were 5.9% (95% confidence interval [CI], 1.0 to 17.4) and 24% (95% CI, 11 to 39), respectively. The 2-year relapse rate was 26% (95% CI, 13 to 42). Cumulative incidences of acute and chronic GVHD were 21% and 44%, respectively. The 2-year PFS was 50% (95% CI, 32 to 65) and OS was 56% (95% CI, 38 to 71). For patients with AML in first complete remission, 2-year PFS and OS were both 82% (95% CI, 55 to 94). RIC with busulfan and clofarabine leads to successful engraftment with acceptable rates of NRM and GVHD.

El-Jawahri A ，Li S ，Ballen KK ，Cutler C ，Dey BR ，Driscoll J ，Hunnewell C ，Ho VT ，McAfee SL ，Poliquin C ，Saylor M ，Soiffer RJ ，Spitzer TR ，Alyea E ，Chen YB ... -  《-》

Intravenous busulfan-cyclophosphamide as a preparative regimen before allogeneic hematopoietic stem cell transplantation for adult patients with acute lymphoblastic leukemia.

The use of i.v. busulfan (BU) instead of the oral formulation can improve outcomes in patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) by reducing toxicity and transplantation-related mortality (TRM). There are limited reports of i.v. BU used to treat patients with acute lymphoblastic leukemia (ALL). The present study was performed to evaluate the efficacy and toxicity of i.v. BU/cyclophosphamide (CY) conditioning in adult ALL. We retrospectively analyzed 42 consecutive patients who underwent allo-HSCT with BU/CY conditioning between January 2007 and October 2010 with an HLA-matched donor (sibling, n = 18; unrelated, n = 24). Thirty-three patients were in first complete remission (CR1), 2 were in second complete remission (CR2), and 7 were in a more advanced stage. Median patient age was 28 years (range, 17∼55 years). The median follow-up was 15 months (range, 1∼48 months). Overall, 13 patients died, for a 30-month overall survival of 56.5% ± 10.6% (65.7% ± 12.5% for patients in CR1 vs 25.4% ± 15.5% for those in CR2 or beyond; P < .001). Eleven patients experienced relapse between 2 and 26 months after allo-HSCT, with a 30-month relapse rate (RR) of 40% ± 10.9% (32.0% ± 12.7% for patients in CR1 vs 71.4% ± 17.1% for those in CR2 or beyond; P = .001). The incidence of grade II-IV acute graft-versus-host disease (GVHD) was 39.2% ± 8.8%, and that of grade III-IV acute GVHD was 7.4% ± 4.1%. The incidence of chronic GVHD was 63.9% ± 11.7%, and that of extensive chronic GVHD was 19.3% ± 7.9%. Only 2 cases of clinically diagnosed veno-occlusive disease (VOD) were documented (4.7%), and 1 of these patients died of severe VOD. Other BU/CY conditioning-associated toxicities were diffuse alveolar hemorrhage in 1 patient and hemorrhagic cystitis in 8 patients. Four patients died due to TRM, for a 30-month TRM of 9.7% ± 4.6%. This study demonstrates that i.v. BU/CY can be considered a feasible conditioning regimen for adult ALL, with low incidences of VOD and TRM.

Tang W ，Wang L ，Zhao WL ，Chen YB ，Shen ZX ，Hu J ... -  《-》