白消安诱导构建胎鼠肢体畸形模型的研究

目的用易获得的化学药物建立大鼠四肢畸形发生率稳定、畸形类型特异的动物模型。方法采用抗肿瘤类致畸药物白消安作为受试物,观察不同剂量和不同给药时间的胎仔畸形率、畸形类型及特征。结果在大鼠受孕第12天(GD12),一次经口给予白消安25mg/kg时,胎仔畸形类型主要为肢体畸形。肢体畸形率以活胎计为37.9%(33/87),以窝计为61.5%(8/13)。畸形类型常见于多指(趾)和缺指(趾),掌跖骨缺失和骨化不全发生率也较高。此外,还发生胫骨缺失和骨化不全,在观察大体形态时所见的短肢是由胫腓骨缺失和发育不全所致。四肢畸形的发生率和严重程度存在着不对称性,后肢较前肢出现率高,缺指(趾)畸形较其他畸形出现率高。结论成功建立大鼠肢体畸形动物模型,为进一步分析研究肢体发育畸形的分子机制和潜在原因奠定了基础。     

马利兰和环磷酰胺预处理方案的非亲缘异基因骨髓移植治疗骨髓增生异常综合征

目的:评估以马利兰和环磷酰胺(Bu-CY2)为预处理方案的非亲缘异基因骨髓移植治疗骨髓增生异常综合征(MDS)的临床疗效。方法:对6例MDS患者进行非亲缘异基因骨髓移植术,以Bu-CY2为预处理方案,Bu 4 m g.k-g 1.d-1,-7 d~-4 d,CY 60 m g.k-g 1.-d 1,-3 d~-2 d。输入单个核细胞数(MNC)为3.38×108/kg(2.4×108/kg~4.6×108/kg),CD 34+细胞数5.81×106/kg(1.2×106/kg~8.5×106/kg),粒-巨噬细胞集落形成单位(CFU-GM)数2.88×105/kg(1.61×105/kg~4.56×105/kg)。以霉酚酸酯加环孢素A(C sA)和短程氨甲蝶呤(MTX)预防移植物抗宿主病,前列腺素E1脂质微球预防肝静脉阻塞病。结果:6例患者中性粒细胞≥0.5×109/L的中位时间为18 d(13~21 d),血小板≥20×109/L的中位时间为21 d(13~24 d)。经DNA短串联重复序列多态性分析和染色体检查,均为供者骨髓植活。早期死亡率为0,移植后随访时间为27个月(6~60个月)。目前实际无病生存6例,缓解期实际生存率100%。结论:以Bu-CY2为预处理方案的非亲缘异基因骨髓移植是治疗MDS的有效方法。     

Effect of Weight and Maturation on Busulfan Clearance in Infants and Small Children Undergoing Hematopoietic Cell Transplantation

Little information is currently available regarding the pharmacokinetics (PK) of busulfan in infants and small children to help guide decisions for safe and efficacious drug therapy. The objective of this study was to develop an algorithm for individualized dosing of i.v. busulfan in infants and children weighing ≤12 kg, that would achieve targeted exposure with the first dose of busulfan. Population PK modeling was conducted using intensive time-concentration data collected through the routine therapeutic drug monitoring of busulfan in 149 patients from 8 centers. Busulfan PK was well described by a 1-compartment base model with linear elimination. The important clinical covariates affecting busulfan PK were actual body weight and age. Based on our model, the predicted clearance of busulfan increases approximately 1.7-fold between 6 weeks to 2 years of life. For infants age <5 months, the model-predicted doses (mg/kg) required to achieve a therapeutic concentration at steady state of 600-900 ng/mL (area under the curve range, 900-1350 μM·min) were much lower compared with standard busulfan doses of 1.1 mg/kg. These results could help guide clinicians and inform better dosing decisions for busulfan in young infants and small children undergoing hematopoietic cell transplantation.     

Decreased incidence of hepatic veno-occlusive disease and fewer hemostatic derangements associated with intravenous busulfan vs oral busulfan in adults conditioned with busulfan + cyclophosphamide for allogeneic bone marrow transplantation

We investigated the occurrence of hepatic veno-occlusive disease (VOD) after allogeneic bone marrow transplantation (BMT) in 241 adults conditioned with busulfan + cyclophosphamide at a single institute and retrospectively compared 186 patients who received oral busulfan (O-Bu group) with 55 patients who received intravenous busulfan (I-Bu group). Various hemostatic parameters were determined at baseline and on days 0, 7, 14, and 21. Hepatic VOD occurred in 41.7% of the O-Bu group and in 18.5% of the I-Bu group. Multivariate analysis revealed that the I-Bu group had significantly decreased risk of VOD compared to the O-Bu group [p=0.006, odds ratio: (OR) 0.345]. Eleven patients in the O-Bu group and none of the I-Bu group developed severe VOD. A repeated measures analysis of variance (ANOVA) with a between-subjects factor revealed significant differences in post-transplant levels of antithrombin III, tissue plasminogen activator (tPA), plasminogen activator inhibitor 1 (PAI-1), and D-dimer according to the occurrence of VOD. The level of antithrombin III was significantly lower, whereas the level of D-dimer was significantly higher, in the O-Bu group than in the I-Bu group. These findings show that, in adults conditioned with busulfan + cyclophosphamide, intravenous busulfan was associated with significantly decreased incidence of VOD and fewer hemostatic derangements after allogeneic BMT compared to oral busulfan.     

Safety and Efficacy of Targeted-Dose Busulfan and Bortezomib as a Conditioning Regimen for Patients with Relapsed Multiple Myeloma Undergoing a Second Autologous Blood Progenitor Cell Transplantation

Patients with multiple myeloma (MM) who relapse after autologous transplantation have limited therapeutic options. We conducted a prospective, multicenter, phase IIa study to investigate the safety and efficacy of i.v. busulfan (Bu) in combination with bortezomib as a conditioning regimen for a second autotransplantation. Because a safe Bu exposure was unknown in patients receiving this combination, Bu was initially targeted to a total area under the concentration–time curve (AUC) of 20,000 μM × minute. As no concentration-limiting toxicity was observed in 6 patients, this Bu exposure was utilized in the following treatment cohort (n = 24). Individualized Bu dose, based on test dose .8 mg/kg pharmacokinetics (PK), was administered daily for 4 consecutive days starting 5 days before transplantation, followed by a single dose of bortezomib (1.3 mg/m²) 1 day before transplantation. The total mean dose of i.v. Bu (including the test dose and 4-day administration) was 14.2 mg/kg (standard deviation = 2.48; range, 8.7 to 19.2). Confirmatory PK demonstrated that only 2 of 30 patients who underwent transplantation were dosed outside the Bu AUC target and dose adjustments were made for the last 2 doses of i.v. Bu. The median age was 59 years (range, 48 to 73). Median time from first to second transplantation was 28.0 months (range, 12 to 119). Of 26 evaluable patients, 10 patients attained a partial response (PR) or better at 3 months after transplantation, with 2 patients attaining a complete response. At 6 months after transplantation, 5 of 12 evaluable patients had maintained or improved their disease status. Median progression-free survival was 191 days, whereas median overall survival was not reached during the study period. The most common grade 3 and 4 toxicities were febrile neutropenia (50.0%) and stomatitis (43.3%). One transplantation-related death was observed. A combination of dose-targeted i.v. Bu and bortezomib induced PR or better in one third of patients with MM who underwent a second autotransplantation, with acceptable toxicity.     

Unrelated-Donor Bone Marrow Transplantation with a Conditioning Regimen Including Fludarabine, Busulfan, and 4 Gy Total Body Irradiation

We investigated the feasibility of reduced-intensity conditioning with 4 Gy total body irradiation, fludarabine (30 mg/m2 for 6 days), and busulfan (4 mg/kg for 2 days) for bone marrow transplantation from a serologically HLA-matched unrelated donor. Seventeen adult patients (median age, 55 years; range, 27-67 years) with various hematologic malignancies (6 in remission, 11 not in remission) were treated. Successful engraftment was achieved in all patients at a median of day 18 (range, day 14-35) after transplantation, although subsequent secondary graft failure was observed in 2 patients. The cumulative incidence of acute graft-versus-host disease (GVHD) of grades II to IV at day 100 was 48%. With a median follow-up of 286 days (range, 56-687 days), the rates of 1-year overall survival, 100-day nonrelapse mortality, and 1-year nonrelapse mortality were 41%, 14%, and 46%, respectively. Eleven patients died, and the causes of death were relapse (n = 4), pulmonary complications (n = 4), acute GVHD (n = 2), and sepsis (n = 1). The remaining 6 patients (at transplantation, 2 were in remission, and 4 were not in remission) are currently still in remission. These results suggest that this regimen reduces the risk of graft failure, but further studies are needed to ameliorate transplantation-related toxicities, primarily GVHD and/or pulmonary complications.     

静脉剂型白消安为主的预处理方案对接受异基因造血干细胞移植的白血病患者的疗效及相关毒性

背景与目的:白消安(busulfan,Bu)是异基因造血干细胞移植预处理方案中的常用药物,口服Bu由于胃肠道吸收不稳定,影响移植疗效且毒性风险增加.本研究评价静脉剂型Bu联合环磷酰胺(cyclophosphamide,Cy)(Bu/Cy)作为异基因外周血干细胞移植(allogeneic peripheral blood stem cell transplantation,allo-PBSCT)预处理方案的疗效和安全性.方法:15例白血病患者采用静脉剂型Bu/Cy,20例采用口服Bu/Cy预处理方案,观察两组的疗效及相关毒性.结果:静脉剂型Bu组15例(100.0%)患者获得造血重建,中性粒细胞和血小板植活中位时间分别为移植后12(9～15)天和15(11～24)天,急性移植物抗宿主病(acute graft versus host disease,aGVHD)6例(40.0%),其中Ⅰ～Ⅱ度4例,Ⅲ～Ⅳ度2例.预处理相关毒性,7例(46.6%)发生呕吐,1例(6.7%)口腔粘膜炎,1例(6.7%)出血性膀胱炎,2例(13.3%)肝功能损害.中位随访时间为180(35～420)天,14例(93.3%)截止随访时仍生存,1例死于严重aGVHD合并肺部、中枢神经系统真菌感染.静脉剂型Bu组在肝脏毒性、口腔粘膜炎发生率分别明显低于口服组(13.3% vs.60.0%、6.7% vs.80.0%),差异均有统计学意义(P＜0.01),而在造血重建、aGVHD、胃肠道反应、出血性膀胱炎等方面差异均无统计学意义.结论:静脉剂型白消安组成的Bu/Cy方案作为白血病allo-PBSCT预处理,疗效确切且毒副作用降低.     

Population pharmacokinetics of oral busulfan in children

Purpose To characterize the population pharmacokinetics of oral busulfan in 48 children including pooled data from three transplantation centres with the aim of estimating the variability in the kinetics of busulfan and to identify covariates that could be used for dose calculation.Methods A total of 508 plasma samples from 250 administrations (mean 9 samples per patient over 4 days of treatment) were collected from 48 children receiving busulfan orally every 6 h. The dosing varied between 13 and 20 mg/kg with seven patients receiving a dose of 600 mg/m². The busulfan formulations administered varied considerably. They included 2-mg tablets (Myleran), gelatine capsules, crushed tablets suspended in water and suspension for administration via nasogastric tube. Samples were analysed for busulfan either by HPLC using postcolumn photolysis or by LC-MS. Plasma concentration-time data were analysed by population pharmacokinetic modelling using NONMEM.Results Busulfan kinetics were best described by a one-compartment model (subroutine ADVAN 2 TRANS 2). Residual variability was modelled using a combined additive and proportional error model. The influence of different covariates on the pharmacokinetic parameters was tested. The best results were obtained by inclusion of body surface area (BSA) as a covariate for clearance (Cl/F) and volume of distribution (V/F). The final population estimates were: Cl/F 4.13 l/h per m² ±26%, V/F 21.3 l/m² ±31% and ka 1.31 h^–1 ±110% (population mean ± interindividual variability, IIV). Variability in one patient during the 4 days of treatment (interoccasion variability, IOV) for Cl/F (10%) and V/F (19%) were calculated to be less than interindividual variability, fulfilling the condition for individualization of busulfan dosage regimens.Conclusions In our paediatric population, BSA, not body weight, is the best predictor of Cl/F and V/F. Our final estimations reflect the wide interpatient variability after oral administration of busulfan with an IIV for ka of 110%.     

A higher incidence of relapse for acute lymphocytic leukemia treated with allogeneic hematopoietic stem cell transplantation conditioned with BU-CY<Subscript>2</Subscript> regimen

Objective: To analyze long-term outcome in sixty leukemia patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT) following busulfan and cyclophosphamide (BU-CY2) between 1994 and 2000.Methods: BU-CY2 was used as the conditioning regimen and allo-HSCT was performed for all patients. All the patients were followed-up until August 2001 or death. The leukemia-free survival, relapse and transplant-related mortality were discussed. Results: All 60 patients had sustained engraftment. Acute GVHD occurred in 22 out of 60 patients (36.7%), and the incidence of acute GVHD was 48% in the patients with CML, 30% in AML and 26.7% in ALL. 38 patients are still alive in continuous remission with a median follow-up of 30 months (range 12-84) and 22 patients have died. The main causes of death were acute GVHD in 3 patients, CMV-IP in 7 patients and relapse in 11 patients,the remaining one died of pulmonary infection. Among 11 patients who died of relapse, 8 patients with ALL relapsed in the early stage post transplant (8115, 53.3%), relapse was observed in the remaining 3 patients with AML, and however, no relapse was observed in CML. The probability of disease-free survival at 3 years for CML. AML and ALL patients was 80%, 70% and 26.7%, respectively.Conclusion: This results suggests that BU-CY2 is an effective conditioning regimen in patients with AML and CML, resulting in a low relapse rate and high long-term survival rate, but not as effective in patients with ALL, with a higher incidence of relapse and therefore, not recommended for ALL patients.