Unrelated donor hematopoietic stem cell transplantation for patients with hematologic malignancies using a nonmyeloablative conditioning regimen of fludarabine, low-dose total body irradiation, and rabbit antithymocyte globulin.

Hematopoietic stem cell chimerism can be established after low-dose conditioning regimens, although the risk of donor cell rejection increases for unrelated donor transplantations. We added pretransplantation rabbit antithymocyte globulin (6 mg/kg) to an established conditioning regimen of fludarabine (90 mg/m2) and single-fraction total body irradiation (200 cGy) followed by postgrafting immunosuppression with cyclosporine A and mycophenolate mofetil for 22 patients with hematologic malignancies. One patient rejected the graft and successfully underwent transplantation with cells from a second donor by using the same conditioning regimen. The actuarial probability of developing acute graft-versus-host disease grade II to IV before day 100 was 40%, although 9 of 14 patients who survived beyond 100 days developed chronic graft-versus-host disease. These data support a hypothesis that the addition of antithymocyte globulin decreases the risk of graft-versus-host and host-versus-graft reactions when combined with a nonmyeloablative conditioning regimen of fludarabine and total body irradiation.     

What role is there for antithymocyte globulin in allogeneic nonmyeloablative canine hematopoietic cell transplantation?

We investigated whether pretransplantation immunosuppression with canine-specific rabbit antithymocyte globulin (ATG), combined with a suboptimal dose of 1 Gy of total body irradiation (TBI), would permit engraftment of canine dog leukocyte antigen-identical marrow. Cumulative ATG doses of 2 to 5 mg/kg produced a T-cell depletion of 1 log in the peripheral blood and 50% in the lymph nodes. Serum levels of ATG peaked on days 4 to 6 after initiation of therapy and became undetectable by day 13 as a result of canine antibody responses to ATG. ATG prolonged allogeneic skin graft survival to 14 days (n = 5), compared with 8 days in control dogs (P = .0003). Five dogs were given marrow transplants after ATG (3.5-5 mg/kg) and 1 Gy of TBI. Posttransplantation immunosuppression consisted of mycophenolate mofetil and cyclosporine. All dogs showed initial engraftment, with maximum donor chimerism levels of 25%. However, only 1 dog achieved sustained engraftment, and 4 rejected their grafts. The duration of engraftment ranged from 8 to > or = 36 weeks (median, 11 weeks), and this is comparable to that in 6 historical controls not given ATG (range, 3-12 weeks; median, 10 weeks; P = .20). The total nucleated cell doses in the marrow grafts had the highest correlation coefficient with the duration of engraftment: 0.82 (P = .09). We concluded that administering ATG before an otherwise suboptimal conditioning dose of 1 Gy of TBI failed to secure uniform stable hematopoietic engraftment.     

Tacrolimus and mycophenolate mofetil after nonmyeloablative matched-sibling donor allogeneic stem-cell transplantations conditioned with fludarabine and low-dose total body irradiation.

We evaluated tacrolimus/mycophenolate mofetil (MMF) for graft-versus-host disease (GVHD) prophylaxis after a nonmyeloablative stem cell transplantation (NST) from a matched sibling donor (MSD). Thirty-two patients (median age, 57 years) with advanced hematologic malignancies, who were poor candidates for a conventional myeloablative transplantation, received fludarabine (30 mg/m(2), day -4 to day -2), total-body irradiation (TBI) (200 cGy, day 0), infusion of donor peripheral blood progenitor cells (day 0), oral tacrolimus 0.06 mg/kg twice daily (from day 3), and oral MMF at 15 mg/kg twice daily (days 0-+27). Tacrolimus was tapered from day +100 to day +180 in those patients with indolent malignancies (n = 25), and from day +35 to day +56 in those with aggressive tumors (n = 7). Regimen toxicities and myelosuppression were mild, allowing 75% of patients to have entirely outpatient transplantations. One patient (3%) experienced a nonfatal graft rejection. Rates of grades II-IV and III-IV acute GVHD were 15.6% and 3%, respectively. Acute GVHD was diagnosed at median day +78 (range, days +31-+84). Extensive chronic GVHD was observed in 10 of 24 evaluable patients (41.6%) at a median onset of day +198 (range, days +128-+277), either spontaneously (n = 5) or elicited after tumor progression (n = 5). Five patients experienced transplantation-related mortality (TRM) (15.6%) from either acute GVHD-related multiorgan failure (MOF) (n = 3) or infectious complications (n = 2). At median follow-up of 19 months (range, 2-41 months), the overall survival, progression-free survival, and disease-free survival rates are 62.5%, 50%, and 40%, respectively. In conclusion, the use of tacrolimus/MMF after MSD NST is associated with encouraging rates of GVHD control.     

Multicenter experience using total lymphoid irradiation and antithymocyte globulin as conditioning for allografting in hematological malignancies

A non myeloablative conditioning with total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) was shown to protect against graft-versus-host disease (GVHD). To evaluate the effects of TLI-ATG in a multicenter study, 45 heavily pretreated patients, median age 51, with lymphoid (n = 38) and myeloid (n = 7) malignancies were enrolled at 9 centers. Twenty-eight patients (62%) received at least 3 lines of treatment before allografting, and 13 (29%) had refractory/relapsed disease at the time of transplantation. Peripheral blood hematopoietic cells were from HLA identical sibling (n = 30), HLA-matched (n = 9), or 1 antigen HLA-mismatched (n = 6) unrelated donors. A cumulative TLI dose of 8 Gy was administered from day -11 through -1 with ATG at the dose of 1.5 mg/kg/day (from day -11 through -7). GVHD prophylaxis consisted of cyclosporine and mycophenolate mofetil. Donor engraftment was reached in 95% of patients. Grade II to IV acute GVHD (aGVHD) developed in 6 patients (13.3%), and in 2 of these patients, it developed beyond day 100. Incidence of chronic GVHD (cGVHD) was 35.8%. One-year nonrelapse mortality was 9.1%. After a median follow-up of 28 months (range, 3-57 months) from transplantation, median overall survival was not reached, whereas median event-free survival was 20 months. This multicenter experience confirms that TLI-ATG protects against GVHD and maintains graft-vs-tumor effects.     

The Basel experience with total body irradiation for conditioning patients with acute leukemia for allogeneic bone marrow transplantation.

We are reporting our experience with 13 patients suffering from end stage acute leukemia that were prepared for allogeneic bone marrow transplantation by combined chemotherapy followed by high dose cyclophosphamide (Cy) and total body irradiation (TBI). Only one patient became a long term survivor. Of the evaluable 12 patients, 6 died of interstitial pneumonia, 4 of GvH and 1 of recurrent leukemia. We conclude that adding combined chemotherapy to the standard conditioning program with Cy and TBI probably increases the risk of developing fatal interstitial pneumonia without eliminating the risk of recurrent leukemia. We suggest that allogenic marrow grafts should be performed earlier in the course of refractory acute leukemias, because in patients with end stage disease its chances of being curative are small.     

Acute and chronic graft-versus-host disease after ablative and nonmyeloablative conditioning for allogeneic hematopoietic transplantation.

In this study, we evaluated the influence of nonmyeloablative and ablative conditioning regimens on the occurrence of acute and chronic graft-versus-host disease (GVHD). One hundred thirty-seven patients undergoing matched-related sibling transplantations received the same GVHD prophylaxis. Myeloablative regimens included intravenous busulfan/cyclophosphamide (n=45) and fludarabine/melphalan (n=29). Patients in the nonmyeloablative group (n=63) received fludarabine/idarubicin/cytarabine, cisplatin/fludarabine/idarubicin, and fludarabine/cyclophosphamide. The actuarial rate of grade II to IV acute GVHD was significantly higher (hazard ratio, 3.6; 95% confidence interval, 1.5-8.8) in patients receiving ablative regimens (36%) compared with the nonmyeloablative group (12%). The cumulative incidence of chronic GVHD was higher in the ablative group (40%) compared with the nonmyeloablative group (14%). The rates were comparable within the first 200 days and were significantly higher in the ablative group beyond day 200 (hazard ratio, 5.2; 95% confidence interval, 1.2-23.2). Nonrelapse and GVHD-related mortality were relatively low in both groups. The use of the described nonmyeloablative preparative regimens was associated with a reduced incidence of grade II to IV acute GVHD and chronic GVHD compared with the busulfan/cyclophosphamide and fludarabine/melphalan transplant regimens. It is interesting to note that nonrelapse mortality with nonmyeloablative regimens in older and more debilitated patients was low (14%) and comparable to that achieved with standard high-dose regimens in younger patients.     

The importance of age, fludarabine, and total body irradiation in the incidence and severity of chronic renal failure after allogeneic hematopoietic cell transplantation.

Nonmalignant late effects, including chronic renal failure (CRF), impair the quality of life of long-term survivors after allogeneic hematopoietic cell transplantation. One of the major risk factors is the use of total body irradiation (TBI) in the preparative regimen; TBI is currently fractionated in an attempt to reduce toxicity. We analyzed 241 patients who had TBI-based preparative regimens for allogeneic hematopoietic cell transplantation. TBI was delivered as a single fraction of 7.5 Gy (7.5S group), 12 Gy in 6 fractions (12F group), or 14.4 Gy in 8 fractions (14.4F group). The cumulative incidence of CRF at 2 years was 12%. Statistical analysis revealed that older age (P < .001) and fludarabine administration (P = .016) had a significant effect on the incidence of CRF. Furthermore, single-fraction TBI was also significantly associated with CRF severity, because 7 (6.3%) of 111 patients in the 7.5S group developed severe CRF, as opposed to 1 (0.8%) of 130 patients in the 12F and 14.4F groups combined (P = .044). However, these conclusions should be regarded as preliminary in view of the retrospective and nonrandomized nature of this study.     

Heterogeneous clearance of antithymocyte globulin after CD34+-selected allogeneic hematopoietic progenitor cell transplantation.

Antithymocyte globulins (ATG) are purified, concentrated preparations of polyclonal immunoglobulin G from hyperimmune serum of horses or rabbits immunized with human thymus lymphocytes. Both the horse and the rabbit products induce immunosuppression as a result of lymphocyte depletion and immune modulation. The exact mechanism of action is unknown but may include T-cell clearance from the circulation and modulation of T-cell activation, homing, and cytotoxic activities. Both horse and rabbit ATG include multiple antibodies against T-cell surface antigens and have been used extensively in allogeneic hematopoietic progenitor cell transplantation (HPCT) for the treatment and prevention of graft-versus-host disease or graft rejection. To quantify the active ATG after HPCT, we developed a flow-based assay to measure residual ATG capable of binding to lymphocytes. In contrast to prior assays that measure total rabbit or horse immunoglobulin, this assay quantitates only the antibody capable of binding to lymphocytes, which presumably reflects the functionally active fraction of the xenoantiserum. Thirty patients with hematologic malignancies underwent T cell-depleted HPCT and had ATG levels assayed during the peritransplantation period. The time required for ATG levels to decay to background was quite variable (mean, 46 days; range, 14-91 days), although most patients demonstrated a rapid early clearance followed by a slower decline. The actual mean half-life was 6.8 days (range, 2.4-14.0 days). The persistence of ATG for months after administration has significant implications for the pace of immune reconstitution after transplantation and is a potentially confounding variable in any study that involves early administration of donor lymphocyte infusions or other cellular transfer. These findings indicate that ATG levels should be explicitly measured in studies that involve early donor lymphocyte administration so that proper conclusions regarding dose, safety, and efficacy can be reached.     

Host conditioning with total lymphoid irradiation and antithymocyte globulin prevents graft-versus-host disease: the role of CD1-reactive natural killer T cells.

Our previous studies in mice showed that the nonmyeloablative conditioning regimen of fractionated irradiation of the lymphoid tissues (total lymphoid irradiation; TLI) and depletive anti-T-cell antibodies (anti-thymocyte serum) markedly increased the percentage of regulatory DX5+ and natural killer 1.1+ T cells in the mouse spleen, and prevented acute lethal graft-versus-host disease (GVHD) in BALB/c mice (H-2(d)) following the transplantation of bone marrow (BM) and peripheral blood mononuclear cells (PBMC) from C57BL/6 (H-2(b)) donors. The object of the current study was to determine whether the TLI and anti-thymocyte serum regimen protected natural killer T-cell deficient CD1(-/-) BALB/c mice against GVHD after BM and PBMC transplantation from C57BL/6 donors, and whether a similar conditioning regimen of TLI and anti-thymocyte globulin (ATG) can prevent GVHD in Lewis rat (RT1(l)) hosts after BM and PBMC transplantation from ACI rat (RT1(a)) donors. The experimental results in mice showed that, although wild-type BALB/c hosts are protected in association with a marked increase in CD1- reactive T cells expressing the invariant TCR identified with a CD1 tetramer reagent; CD1(-/-) BALB/c hosts are not. Studies of chimeric donor cells in mice protected from GVHD showed donor T-cell polarization to a Th2 cytokine pattern. Results in rats showed that approximately 1000 fold more donor PBMC cells were required to induce a similar incidence of lethal GVHD in TLI and ATG conditioned hosts as compared with hosts conditioned with single-dose total-body irradiation or total-body irradiation and ATG. Surviving TLI and ATG conditioned rat hosts were complete chimeras. In conclusion, the TLI and ATG/anti-thymocyte serum conditioning regimen protects against GVHD in rats and mice, and regulatory natural killer T cells are required for protection.     

Effect of total body irradiation dose escalation on outcome following T-cell-depleted allogeneic bone marrow transplantation.

Prior studies of non-T-cell-depleted (TCD) transplantation have demonstrated a reduction in relapse in patients receiving escalated doses of TBI; however, overall survival in these studies was not significantly improved due to increased treatment-related toxicity seen at the higher doses of irradiation. Toxicity was in part related to an increased incidence of GVHD. Because T-cell depletion of donor bone marrow reduces the incidence of GVHD and other treatment-related complications after allogeneic bone marrow transplantation, it was postulated that TBI dose may be safely escalated in this setting and may decrease the risk of relapse following TCD BMT. Herein, we report the results of a trial assessing the safety and impact of escalated doses of TBI after TCD BMT. Two hundred adults with hematologic malignancies were treated in consecutive cohorts defined by increasing doses of TBI (1400, 1480, and 1560 cGy) in combination with cyclophosphamide. In vitro T-cell depletion using anti-CD6 monoclonal antibody was used for GVHD prophylaxis. The incidence of grade II or greater acute GVHD in patients receiving 1560 cGy (36%) was significantly higher than in patients receiving 1400 cGy (18%) (P = .04) or 1480 cGy (13%) (P = .01). Two-year treatment-related mortality was significantly higher in patients who received 1560 cGy of TBI (33%) than in those who received 1400 cGy (20%) (P = .04) or 1480 cGy (19%) (P = .05). The increased dose of TBI did not reduce the rates of relapse, with the estimated 2-year risk of relapse being 24% (1400 cGy), 24% (1480 cGy), and 31% (1560 cGy) for the 3 cohorts of patients. Overall survival at 2 years was inferior for patients receiving 1560 cGy of TBI (36%) compared with those who received 1400 cGy (55%) or 1480 cGy (58%) (P = .01). We conclude that dose escalation of TBI is associated with increased GVHD and inferior survival following TCD BMT. Future efforts to reduce the risk of relapse after TCD BMT should focus on immunologic methods to induce the graft-versus-leukemia effect after BMT rather than intensification of the ablative regimen by escalation of irradiation dose.     

Successful allogeneic stem cell transplantation with nonmyeloablative conditioning in patients with relapsed hematologic malignancy following autologous stem cell transplantation.

The use of myeloablative preparative therapy and allogeneic stem cell transplantation (alloSCT) as salvage therapy for adult patients with relapsed hematologic malignancy after autologous stem cell transplantation (autoSCT) is generally unsuccessful due to very high treatment-related mortality rates. We evaluated the outcome of HLA-matched related donor alloSCT following nonmyeloablative preparative therapy in 13 patients (median age, 38 years) with relapsed hematologic malignancies (Hodgkin's disease, n = 4; Hodgkin's disease and advanced myelodysplastic syndrome, n = 1; non-Hodgkin's lymphoma, n = 6; multiple myeloma, n = 2) after initial autoSCT. Median time from autoSCT to alloSCT was 12 months (range, 3-24 months); 6 patients had chemotherapy-refractory disease following autoSCT, 6 were in untreated relapse, and 1 had a partial response from salvage chemotherapy. Preparative therapy consisted of cyclophosphamide, 150-200 mg/kg; peritransplantation anti-thymocyte globulin; thymic irradiation (in patients who had not received previous mediastinal irradiation); and a very short course of cyclosporine as GVHD prophylaxis. All patients achieved initial mixed chimerism as defined by greater than 1% donor peripheral white blood cells. Seven patients, who had no evidence of GVHD, received prophylactic DLI beginning 5 to 6 weeks after transplantation for conversion of mixed chimerism to full donor hematopoiesis and to optimize a graft-versus-tumor effect. Six patients showed conversion to full donor chimerism and 1 lost the graft. Grade II or greater acute GVHD occurred in 9 patients. Seven patients achieved a complete response; 6 had no response. The median survival time of the 13 patients is currently 10 months (range, 3-39 months), with an overall survival probability at 2 years of 45% (95% confidence interval [CI], 19%-73%) and a disease-free survival probability at 2 years of 37.5% (95% CI, 12%-65%). Thus, this novel nonmyeloablative alloSCT strategy followed by prophylactic DLI was well tolerated and can result in durable disease-free survival among patients with advanced hematologic malignancies after a failed autoSCT. Further follow-up and evaluation of additional patients are required to conclusively establish the role of this strategy in the treatment of hematologic malignancies after an autologous transplantation.     

Prediction and prevention of transplant-related mortality from pulmonary causes after total body irradiation and allogeneic stem cell transplantation.

Between July 1997 and August 2004, 146 consecutive patients with hematologic malignancies received a T cell-depleted peripheral blood stem cell transplant from an HLA-identical sibling by using total body irradiation (TBI) and cyclophosphamide conditioning regimens. Eighty-five patients received 13.6 Gy of TBI with no lung shielding, and 61 received lung shielding (total lung dose, 6-12 Gy). Ninety-four patients (65.5%) had standard-risk disease; the remainder had more advanced disease or unfavorable diagnoses. Of the 21 transplant-related deaths, 14 were from pulmonary causes (10 idiopathic pulmonary syndromes and 4 from infection) that occurred at a median of 90 days (range, 23-238 days) after transplantation. Independent risk factors for pulmonary transplant-related mortality (PTRM) were pretransplantation diffusion capacity for carbon monoxide (relative risk, 5.7 for diffusion capacity for carbon monoxide <85%), smoking (relative risk, 5.0), and CD34 cell dose (relative risk, 9.4 for a CD34 dose of <5 x 10(6) cells per kilogram). Patients receiving lung shielding had significantly lower PTRM (3.3% versus 14.1%; P = .02) and better overall survival (70% +/- 6% versus 52% +/- 5%; P = .04), but lung shielding was not a significant independent factor for determining PTRM. These results suggest that pulmonary mortality after TBI-based preparative regimens is predictable and that higher CD34 cell doses can reduce the risk.     

Relapse after allogeneic bone marrow transplantation for refractory anemia is increased by shielding lungs and liver during total body irradiation.

Patients with the refractory anemia (RA) subtype of myelodysplastic syndrome who undergo allogeneic bone marrow transplantation (BMT) have a low risk of relapse, but they have a high risk of nonrelapse mortality when prepared with conventional preparative regimens. To try to reduce nonrelapse mortality, we treated 14 RA patients with a modified approach to total body irradiation (TBI) followed by cyclophosphamide (CY) and HLA-identical sibling BMT. Median patient age was 44 years (range, 28 to 65 years). Patients received TBI with shielding of the right lobe of the liver and both lungs followed by electron beam boosts to shielded ribs. Total radiation exposure in nonshielded areas was 12 Gy (n = 10), 10 Gy (n = 3), or 6 Gy (n = 1). After TBI, patients received CY at 120 mg/kg over 2 days, followed by transplantation of unmanipulated bone marrow. All patients initially achieved engraftment with donor cells, although 2 patients had subsequent reemergence of host hematopoiesis without evidence of disease relapse. Five patients died of transplantation-related causes between 22 and 1262 days post-BMT. Four patients relapsed between 157 and 1096 days post-BMT. These 14 patients were compared with 46 historical controls with RA who received conventional CY/TBI or busulfan/CY preparative regimens. Patients in the experimental group had a similar nonrelapse mortality rate compared with the historical control group (29% versus 37%, respectively; P = .8), but a higher relapse rate (34% versus 2%, P = .0004) and a lower disease-free survival (38% versus 61%, P = .16). We conclude that this modified TBI approach is associated with an unacceptably high risk of relapse for patients with RA undergoing BMT.     

Maximally tolerated busulfan systemic exposure in combination with fludarabine as conditioning before allogeneic hematopoietic cell transplantation

Systemic exposure to high-dose busulfan has been correlated with efficacy and toxicity after hematopoietic cell transplantation for malignancy. We used the area under the concentration-time curve (AUC) to prospectively determine the maximally tolerated systemic exposure to i.v. busulfan when given once daily after fludarabine administered at 40 mg/m(2) for 4 days. Three target AUC levels were planned: 6,000, 7,500, and 9,000 μM-min. Included were patients 16 to 65 years old, with a hematologic malignancy, an HLA A, B, or C, DRB1 8/8 or 7/8 matched donor, Karnofsky performance status ≥70%, and adequate organ function. For level 1 patients, i.v. busulfan doses 1 and 2 were 170 mg/m(2)/day, then doses 3 and 4 were adjusted based on first-dose pharmacokinetic modeling to achieve an average daily AUC of 6,000 μM-min. Doses 1 and 2 for the subsequent cohorts were based on the level 1 data: 180 mg/m(2)/day for AUC 7,500 μM-min (level?2) and 220 mg/m(2)/day for AUC 9,000 μM-min (level 3), with pharmacokinetic targeting for doses 3 and 4. Pharmacokinetic analysis after the last dose showed that 88% of the patients had been exposed to a mean AUC within 10% of the target. Forty patients were treated at level 1, 29 patients at level 2, and three patients at level 3. DLT was veno-occlusive disease of the liver, which occurred in none of 40 patients (0%) at level 1, two of 29 patients (7%) at level 2, and three of three patients (100%) at level 3. Dermatitis (P < .01) and pulmonary toxicity (P = .01) were also increased at higher AUC levels. Level 2 (7,500 μM-min × 4 days) was the maximally tolerated AUC. Within the confines of the trial's small sample size, there was no suggestion that escalating busulfan AUC from 6,000 to 7,500 μM-min × 4 days increased nonrelapse mortality. Assessment of the higher busulfan AUC on relapse prevention requires trials in patients with a homogeneous risk of relapse.     

Once-daily intravenous busulfan given with fludarabine as conditioning for allogeneic stem cell transplantation: study of pharmacokinetics and early clinical outcomes.

The availability of an i.v. form of busulfan (Bu) has prompted investigation of administration schedules other than the 4-times-daily dosage commonly used with oral Bu. We have studied an allogeneic stem cell transplantation (SCT) preparative regimen comprising fludarabine (FLU) 50 mg/m2 on days -6 to -2 plus i.v. Bu 3.2 mg/kg daily in a 3-hour infusion on days -5 to -2. The regimen was given to 70 patients aged 15 to 64 years (median, 41 years) with hematologic malignancy. Thirty-six patients (51%) had high-risk malignancy, 28 (40%) had unrelated or genotypically mismatched related donors (alternate donors [AD]) and 29 (41%) received bone marrow rather than blood as stem cell source. Acute GVHD prevention comprised antithymocyte globulin 4.5 mg/kg over 3 days pretransplantation, cyclosporin A, and short-course methotrexate with folinic acid. Hepatic toxicity was transient and there was no clinically diagnosed veno-occlusive disease. Grade II stomatitis occurred in 49 patients (70%) and hemorrhagic cystitis in 9 patients (13%). One patient with subtherapeutic phenytoin levels had a convulsion 8 hours after the third i.v. Bu dose, but no other neurotoxicity was apparent. Incidence of acute GVHD grades II to IV was 8% and incidence of grade III-IV was 3%, with no deaths from this cause. Actuarial incidence of chronic GVHD at 2 years is 38%. There were 2 cases of graft failure in unrelated donor BMT recipients, 1 of which was reversed by asecond transplantation. With a median follow-up of 16 months (range, 6-27 months), transplantation-related mortality at 100 days and 2 years was 2% and 5% for matched related donor (MRD) SCT and 8% and 19% for AD SCT, respectively (P = not significant). Relapse rates were 21% for 34 patients with acute myeloid leukemia (AML) in complete remission or chronic myeloid leukemia in chronic phase (low-risk), 66% for 19 patients with high-risk AML, and 18% for 17 patients with other active malignancy. Projected disease-free and overall survival rates at 2 years were 74% and 88% for low-risk disease, 26% and 37% for advanced AML, and 65% and 71% for other high-risk disease, respectively. Pharmacokinetic studies were done using 11 samples with the first and fourth doses of Bu. Kinetics were linear, and for the first and fourth doses, the half-lives were 2.60 +/- 0.44 and 2.57 +/- 0.36 hours, respectively. Clearances were 106.77 +/- 16.68 and 106.86 +/- 21.57 mL/min per m2, peak concentrations (Cmax) were 3.92 +/- 0.31 and 3.96 +/- 0.28 mcg/mL, and Bu areas under the plasma concentration versus time curve (AUC) were 4866.51 +/- 771.42 and 4980 +/- 882.80 microM x min, respectively. Bu was completely cleared within 24 hours and the day 4 pharmacokinetic values were very similar to those on day 1 for every patient. The cumulative AUC was comparable to the target range established for p.o. Bu. This regimen incorporating once-daily i.v. Bu is convenient to give, is relatively well tolerated, gives predictable blood levels, and deserves further study in circumstances in which cytoreduction as well as immune suppression is needed.     

阿伦和达珠单抗与抗胸腺蛋白对肾移植的有效性及安全性比较

背景：免疫抑制剂是通过影响机体的体液免疫和细胞免疫抑制机体的免疫功能来完成抗急性排斥反应,提高人/肾存活率。 目的：比较3种免疫抑制诱导剂阿伦单抗、达珠单抗和抗胸腺蛋白在肾移植免疫诱导中的有效性与安全性。 方法：运用Cochrane系统评价法,检索1966年至2011年PUBMED,EMBASE等数据库。纳入阿伦单抗、达珠单抗和抗胸腺蛋白3种药物在肾移植中的随机对照试验(RCT)进行Meta分析。 结果与结论：9个RCT的777例患者纳入分析,3种药物24个月的人/肾存活率和急性排斥发生率差异无显著性意义(均P > 0.05)。随访36个月时,阿伦单抗感染率显著低于抗胸腺蛋白(P < 0.05)。分析结果表明,3种药物的免疫诱导效果相近;随访36个月时,阿伦单抗较抗胸腺蛋白的感染率低。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Long-term remissions in patients with myelodysplastic syndrome and secondary acute myelogenous leukemia undergoing allogeneic transplantation following a reduced intensity conditioning regimen of 550 cGy total body irradiation and cyclophosphamide.

We analyzed outcomes of patients with myelodysplastic syndrome (MDS) or secondary acute myelogenous leukemia (sAML) that were treated at our institution with a reduced intensity conditioning (RIC) regimen of 550-cGy total body irradiation and cyclophosphamide followed by related donor (RD) or unrelated donor (URD) transplantation. Fifty-one consecutive patients with MDS or sAML received this RIC regimen and URD (n = 30) or RD (n = 21) stem cells. Graft-versus-host disease prophylaxis consisted of cyclosporine alone (RD) or with corticosteroids and methotrexate (URD). Median patient age was 44 years. With a median follow-up of 3.7 years after transplantation in the 19 surviving patients (37%), Kaplan-Meier estimates of overall survival were 88%, 46%, 33%, and 11% for patients transplanted with sAML in remission, refractory anemia, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, or sAML refractory/untreated, respectively. Kaplan-Meier estimates of relapse-free survival were 75%, 46%, 33%, and 11%, respectively. Overall, the cumulative incidences of relapse and transplant-related mortality were 27% and 37%, respectively. In patients with MDS, this is an effective RIC regimen for allogeneic transplantation that can be used as an alternative to other RIC or conventional conditioning regimens.     

以FCA预处理的造血干细胞移植治疗SAA的临床研究

目的探讨以氟达拉滨（Flu）、低剂量环磷酰胺（CTX）和抗胸腺细胞球蛋白（ATG）为预处理的FCA方案异基因造血干细胞移植治疗重型再生障碍性贫血（SAA）的疗效及安全性。方法用FCA预处理方案预处理移植治疗SAA-Ⅰ型和SAA-Ⅱ型患者各2例,其中同胞供者人类白细胞抗原（HLA）低分辨配型（6/6位点）全相合的骨髓联合外周血造血干细胞移植3例、非血缘关系高分辨HLA配型（10/10位点）全相合的外周血造血干细胞移植1例。同胞供者的预处理方案：Flu30mg·m-2d-1×5d,CTX50～60mg·kg-1d-1×5d,ATG3mg·kg-1d-1×3d。非血缘关系的预处理方案：CTX20mg·kg-1d-1×2d,ATG5mg·kg-1d-1×3d,Flu30mg·m-2d-1×4d。移植物抗宿主病（GVHD）的预防：均采用低剂量环孢素A（CsA）联合低剂量短程甲氨蝶呤（MTX）,非血缘关系移植加用霉酚酸酯（MMF）0.5gbid,＋1d～＋28d。观察移植并发症、输血量、造血重建、嵌合体和生存状态。结果 4例患者均获得造血干细胞的成功植入,移植后中性粒细胞绝对值（ANC）〉0.5×109/L的时间为＋10d～＋15d,血小板（PLT）〉20×109/L的时间为＋10d～＋20d,移植后输注红细胞3～6U,血小板4～10U,随访7～42个月,完全供者嵌合体,血液学完全缓解;患者1出现广泛型慢性移植物抗宿主病（cGVHD）,死于多脏器功能衰竭,其余3例无病生存,其中非血缘关系移植的患者4发生轻度局限型cGVHD和巨细胞病毒血症,经过治疗很快控制。结论 Flu、低剂量CTX和ATG的FCA预处理方案的异基因造血干细胞移植治疗SAA的疗效肯定,患者耐受性好,值得推广。