Myeloablative conditioning regimens for AML allografts: 30 years later

ESTRO ACROP and SIOPE recommendations for myeloablative Total Body Irradiation in children

BACKGROUND AND PURPOSE

Myeloablative Total Body Irradiation (TBI) is an important modality in conditioning for allogeneic hematopoietic stem cell transplantation (HSCT), especially in children with high-risk acute lymphoblastic leukemia (ALL). TBI practices are heterogeneous and institution-specific. Since TBI is associated with multiple late adverse effects, recommendations may help to standardize practices and improve the outcome versus toxicity ratio for children.

MATERIAL AND METHODS

The European Society for Paediatric Oncology (SIOPE) Radiotherapy TBI Working Group together with ESTRO experts conducted a literature search and evaluation regarding myeloablative TBI techniques and toxicities in children. Findings were discussed in bimonthly virtual meetings and consensus recommendations were established.

RESULTS

Myeloablative TBI in HSCT conditioning is mostly performed for high-risk ALL patients or patients with recurring hematologic malignancies. TBI is discouraged in children <3-4 years old because of increased toxicity risk. Publications regarding TBI are mostly retrospective studies with level III-IV evidence. Preferential TBI dose in children is 12-14.4 Gy in 1.6-2 Gy fractions b.i.d. Dose reduction should be considered for the lungs to <8 Gy, for the kidneys to ≤10 Gy, and for the lenses to <12 Gy, for dose rates ≥6 cGy/min. Highly conformal techniques i.e. TomoTherapy and VMAT TBI or Total Marrow (and/or Lymphoid) Irradiation as implemented in several centers, improve dose homogeneity and organ sparing, and should be evaluated in studies.

CONCLUSIONS

These ESTRO ACROP SIOPE recommendations provide expert consensus for conventional and highly conformal myeloablative TBI in children, as well as a supporting literature overview of TBI techniques and toxicities.

Cachectic muscle wasting in acute myeloid leukaemia: a sleeping giant with dire clinical consequences

Acute myeloid leukaemia (AML) is a haematological malignancy with poor survival odds, particularly in the older (>65 years) population, in whom it is most prevalent. Treatment consists of induction and consolidation chemotherapy to remit the cancer followed by potentially curative haematopoietic cell transplantation. These intense treatments are debilitating and increase the risk of mortality. Patient stratification is used to mitigate this risk and considers a variety of factors, including body mass, to determine whether a patient is suitable for any or all treatment options. Skeletal muscle mass, the primary constituent of the body lean mass, may be a better predictor of patient suitability for, and outcomes of, AML treatment. Yet skeletal muscle is compromised by a variety of factors associated with AML and its clinical treatment consistent with cachexia, a life-threatening body wasting syndrome. Cachectic muscle wasting is associated with both cancer and anticancer chemotherapy. Although not traditionally associated with haematological cancers, cachexia is observed in AML and can have dire consequences. In this review, we discuss the importance of addressing skeletal muscle mass and cachexia within the AML clinical landscape in view of improving survivability of this disease.

Treatment of acute myeloid leukemia in children: A practical perspective

Pediatric acute myeloid leukemia (AML) is a heterogeneous disease that requires a multifaceted treatment approach. Although outcomes for low-risk AML have improved significantly over recent decades, high-risk AML continues to be associated with an adverse prognosis. Recent advances in molecular diagnostics, risk stratification, and supportive care have contributed to improvements in outcomes in pediatric AML. Targeted approaches, for example, the use of tyrosine kinase inhibitors to treat FLT3-ITD AML, offer promise and are currently undergoing clinical investigation in pediatric patients. New approaches to hematopoietic stem cell transplantation, including the use of haploidentical donors, are significantly expanding donor options for patients with high-risk AML. This review provides an overview of recent advances in the treatment of pediatric AML that are likely to have clinical impact and reshape the standard of care.

Acute Myeloid Leukemia: From Biology to Clinical Practices Through Development and Pre-Clinical Therapeutics

Recent studies have provided several insights into acute myeloid leukemia. Studies based on molecular biology have identified eight functional mutations involved in leukemogenesis, including driver and passenger mutations. Insight into Leukemia stem cells (LSCs) and assessment of cell surface markers have enabled characterization of LSCs from hematopoietic stem and progenitor cells. Clonal evolution has been described as having an effect similar to that of microenvironment alterations. Such biological findings have enabled the development of new targeted drugs, including drug inhibitors and monoclonal antibodies with blockage functions. Some recently approved targeted drugs have resulted in new therapeutic strategies that enhance standard intensive chemotherapy regimens as well as supportive care regimens. Besides the progress made in adoptive immunotherapy, since allogenic hematopoietic stem cell transplantation enabled the development of new T-cell transfer therapies, such as chimeric antigen receptor T-cell and transgenic TCR T-cell engineering, new promising strategies that are investigated.

Improving hematopoietic recovery through modeling and modulation of the mesenchymal stromal cell secretome

BACKGROUND

Efficient and sustained hematopoietic recovery after hematopoietic stem cell or bone marrow transplantation is supported by paracrine signaling from specific subpopulations of mesenchymal stromal cells (MSCs). Here, we considered whether in vitro mechanopriming of human MSCs could be administered to predictively and significantly improve in vivo hematopoietic recovery after irradiation injury.

METHODS

First, we implemented regression modeling to identify eight MSC-secreted proteins that correlated strongly with improved rescue from radiation damage, including hematopoietic recovery, in a murine model of hematopoietic failure. Using these partial least squares regression (PLSR) model parameters, we then predicted recovery potential of MSC populations that were culture expanded on substrata of varying mechanical stiffness. Lastly, we experimentally validated these predictions using an in vitro co-culture model of hematopoiesis and using new in vivo experiments for the same irradiation injury model used to generate survival predictions.

RESULTS

MSCs grown on the least stiff (elastic moduli ~ 1 kPa) of these polydimethylsiloxane (PDMS) substrata secreted high concentrations of key proteins identified in regression modeling, at concentrations comparable to those secreted by minor subpopulations of MSCs shown previously to be effective in supporting such radiation rescue. We confirmed that these MSCs expanded on PDMS could promote hematopoiesis in an in vitro co-culture model with hematopoietic stem and progenitor cells (HSPCs). Further, MSCs cultured on PDMS of highest stiffness (elastic moduli ~ 100 kPa) promoted expression of CD123+ HSPCs, indicative of myeloid differentiation. Systemic administration of mechanoprimed MSCs resulted in improved mouse survival and weight recovery after bone marrow ablation, as compared with both standard MSC expansion on stiffer materials and with biophysically sorted MSC subpopulations. Additionally, we observed recovery of white blood cells, platelets, and red blood cells, indicative of complete recovery of all hematopoietic lineages.

CONCLUSIONS

These results demonstrate that computational techniques to identify MSC biomarkers can be leveraged to predict and engineer therapeutically effective MSC phenotypes defined by mechanoprimed secreted factors, for translational applications including hematopoietic recovery.

A Single-Center Experience With Hematopoietic Stem Cell Transplantation for Pediatric Acute Lymphoblastic Leukemia: A Modest Pitch for Non-Total Body Irradiation Conditioning Regimens

OBJECTIVES

Allogeneic hematopoietic stem cell transplantation has been used for several decades to treat patients with acute lymphoblastic leukemia. Total body irradiation has been promoted as an important component of conditioning regimens for this process; however, recent reports of chemotherapy-based conditioning regimens have shown comparable outcomes.

MATERIALS AND METHODS

We report our experience with radiation-free conditioning using busulfan and cyclophosphamide in 127 pediatric patients with acute lymphoblastic leukemia who were treated between 1997 and 2014. The median age was 11 years (range, < 1 to 15 y), 70% of patients were male, 81.1% received transplants from HLA-matched siblings, 83% received peripheral blood stem cells, 41% were in second complete remission at the time of transplant, and 83% had B-lineage immunophenotype.

RESULTS

In patients who were in complete remission at the time of transplant, 5-year overall survival, leukemia-free survival, and relapse rates were 62.48% (95% confidence interval, 52.29-71.09%), 49.43% (95% confidence interval, 39.57-58.53%), and 45.64% (95% confidence interval, 35.85-54.88%), respectively. We observed significant differences between outcomes in patients by time of transplant, presence of chronic graft-versus-host disease, and remission status.

CONCLUSIONS

Our relapse rates were comparable to those shown in recent studies, although the transplant-related mortality rate was lower. The results of our study showed that a busulfan/cyclophosphamide conditioning regimen has acceptable outcomes without the undesirable adverse effects of total body irradiation, particularly in pediatric patients. Large multicenter studies are needed to assess less toxic conditioning regimens with fewer adverse effects in these patients.

An investigation on the predominant diseases, its diagnosis, and commonly used drugs in the poultry farms in the North-Eastern regions of Algeria

Aim

An investigation was carried out to assess the occurrence of diseases, its method of diagnosis, and commonly used drugs in poultry farms in North-Eastern regions of Algeria.

Materials and Methods

A total of 265 veterinary doctors were surveyed to obtain information on the dominant diseases, its frequency of occurrence, method of diagnosis, and commonly used drugs in poultry farms.

Results

A study revealed that about 68% of bacterial diseases are due to colibacillosis, mycoplasmosis, and salmonellosis, 22% of viral diseases are due to Newcastle, Gumboro, and infectious bronchitis, and 10% others including coccidiosis and ascites syndrome. The study also showed that about 57% of cases were diagnosed by clinical signs, 36% by necropsy findings, and the remaining 7% through therapeutic and laboratory analysis. Antibiotics, a predominance of the anarchic veterinary drugs, were massively used to control the diseases. Hence, there is a need for strict regulations on the use of veterinary drugs to guarantee food safety.

Conclusion

These results remain non-exhaustive but contribute strongly to determine the status of health of the birds in the region.

Allogeneic Stem Cell Transplant for Acute Myeloid Leukemia: Evolution of an Effective Strategy in India

Purpose There are limited data from developing countries on the role and cost-effectiveness of allogeneic stem cell transplantation (allo-SCT) for patients with acute myeloid leukemia (AML). Patients and Methods We undertook a retrospective descriptive study of all patients with AML who underwent allo-SCT from 1994 to 2013 at our center to evaluate the clinical outcomes and cost-effectiveness of this therapeutic modality. Results Two hundred fifty-four consecutive patients, median age 34 years, who underwent allo-SCT at our center were included in this study. There were 161 males (63.4%). The 5-year overall survival (OS) and event-free survival for the entire cohort was 40.1 ± 3.5% and 38.7 ± 3.4%, respectively. The 5-year OS for patients in first (CR1), second, and third complete remission and with disease/refractory AML was 53.1 ± 5.2%, 48.2 ± 8.3%, 31.2 ± 17.8%, and 16.0 ± 4.4%, respectively ( P < .001). From 2007, reduced intensity conditioning (RIC) with fludarabine and melphalan (Flu/Mel) was used in a majority of patients in CR1 (n = 67). Clinical outcomes were compared with historical conventional myeloablative conditioning regimens (n = 38). Use of Flu/Mel was associated with lower treatment-related mortality at 1 year, higher incidence of chronic graft-versus-host-disease, and comparable relapse rates. The 5-year OS and event-free survival for Flu/Mel and myeloablative conditioning group was 67.2 ± 6.6% versus 38.1 ± 8.1% ( P = .003) and 63.8 ± 6.4% versus 32.3 ± 7.9% ( P = .002), respectively. Preliminary cost analysis suggests that in our medical cost payment system, RIC allo-SCT in CR1 was likely the most cost-effective strategy in the management of AML. Conclusion In a resource-constrained environment, Flu/Mel RIC allo-SCT for AML CR1 is likely the most efficacious and cost-effective approach in a subset of newly diagnosed young adult patients.

Hematopoietic Stem Cell Transplantation Activity in Pediatric Cancer between 2008 and 2014 in the United States: A Center for International Blood and Marrow Transplant Research Report

This Center for International Blood and Marrow Transplant Research report describes the use of hematopoietic stem cell transplantation (HSCT) in pediatric patients with cancer, 4408 undergoing allogeneic (allo) and3076 undergoing autologous (auto) HSCT in the United States between 2008 and 2014. In both settings, there was a greater proportion of boys (n = 4327; 57%), children < 10 years of age (n = 4412; 59%), whites (n = 5787; 77%), and children with a performance score ≥ 90% at HSCT (n = 6187; 83%). Leukemia was the most common indication for an allo-transplant (n = 4170; 94%), and among these, acute lymphoblastic leukemia in second complete remission (n = 829; 20%) and acute myeloid leukemia in first complete remission (n = 800; 19%) werethe most common. The most frequently used donor relation, stem cell sources, and HLA match were unrelated donor (n = 2933; 67%), bone marrow (n = 2378; 54%), and matched at 8/8 HLA antigens (n = 1098; 37%) respectively. Most allo-transplants used myeloablative conditioning (n = 4070; 92%) and calcineurin inhibitors and methotrexate (n = 2245; 51%) for acute graft-versus-host disease prophylaxis. Neuroblastoma was the most common primary neoplasm for an auto-transplant (n = 1338; 44%). Tandem auto-transplants for neuroblastoma declined after 2012 (40% in 2011, 25% in 2012, and 8% in 2014), whereas tandem auto-transplants increased for brain tumors (57% in 2008 and 77% in 2014). Allo-transplants from relatives other than HLA-identical siblings doubled between 2008 and 2014 (3% in 2008 and 6% in 2014). These trends will be monitored in future reports of transplant practices in the United States.

Hepatic Veno-Occlusive Disease Associated with Immunosuppressive Cyclophosphamide Dosing and Roxithromycin

Objective:

To report on a patient developing hepatic veno-occlusive disease while being treated with immunosuppressive doses of cyclophosphamide (≤2 mg/kg).

Case Summary:

A 66-year-old woman with autoimmune hemolytic anemia developed hepatic veno-occlusive disease while being treated with immunosuppressive cyclophosphamide 100 mg/day in combination with roxithromycin (total dose 600 mg/day). After all drugs were stopped, the patient recovered within 2 weeks. The Naranjo probability scale indicated a probable relationship between veno-occlusive disease and treatment with cyclophosphamide in this patient.

Discussion:

Since roxithromycin inhibits CYP3A4, which is involved with cyclophosphamide metabolism, a drug-drug interaction could have been responsible. In addition, roxithromycin is an inhibitor of the drug transporter P-glycoprotein, possibly leading to accumulation of cyclophosphamide in endothelial cells. Alternatively, since cyclophosphamide has been reported to induce apoptosis, roxithromycin could have rendered endothelial cells more vulnerable for apoptosis.

Conclusions:

In specific patients, cyclophosphamide can be associated with hepatic veno-occlusive disease at immunosuppressive doses.

Cellular Reprogramming Allows Generation of Autologous Hematopoietic Progenitors From AML Patients That Are Devoid of Patient-Specific Genomic Aberrations

Current treatments that use hematopoietic progenitor cell (HPC) transplantation in acute myeloid leukemia (AML) patients substantially reduce the risk of relapse, but are limited by the availability of immune compatible healthy HPCs. Although cellular reprogramming has the potential to provide a novel autologous source of HPCs for transplantation, the applicability of this technology toward the derivation of healthy autologous hematopoietic cells devoid of patient-specific leukemic aberrations from AML patients must first be evaluated. Here, we report the generation of human AML patient-specific hematopoietic progenitors that are capable of normal in vitro differentiation to myeloid lineages and are devoid of leukemia-associated aberration found in matched patient bone marrow. Skin fibroblasts were obtained from AML patients whose leukemic cells possessed a distinct, leukemia-associated aberration, and used to create AML patient-specific induced pluripotent stem cells (iPSCs). Through hematopoietic differentiation of AML patient iPSCs, coupled with cytogenetic interrogation, we reveal that AML patient-specific HPCs possess normal progenitor capacity and are devoid of leukemia-associated mutations. Importantly, in rare patient skin samples that give rise to mosaic fibroblast cultures that continue to carry leukemia-associated mutations; healthy hematopoietic progenitors can also be generated via reprogramming selection. Our findings provide the proof of principle that cellular reprogramming can be applied on a personalized basis to generate healthy HPCs from AML patients, and should further motivate advances toward creating transplantable hematopoietic stem cells for autologous AML therapy. Stem Cells2013;33:1839–1849

Pulmonary toxicity following total body irradiation for acute lymphoblastic leukaemia: The Ottawa Hospital Cancer Centre (TOHCC) experience

Purpose

To review the incidence of clinically significant pulmonary toxicity following total body irradiation (TBI) as a part of the conditioning regimen for acute lymphoblastic leukaemia (ALL) patients undergoing bone marrow transplantation (BMT) at The Ottawa Hospital Cancer Centre.

Methods

This is a retrospective review of ALL patients who received TBI in The Ottawa Hospital Bone Marrow Transplant Program (TOH-BMT) as part of their conditioning regimen from 1991 to 2011 inclusive. The patients were treated using a locally developed translating-couch irradiation technique. We have analysed all available data for the first 100 days following TBI to determine the incidence of radiation-induced pulmonary toxicities.

Results

Of the total 622 patients undergoing TBI during the specified period, 88 had ALL. Median age at BMT was 30 years and the conditioning regimens varied. A total of 74 (84%) patients received 12 Gy/6 F/BID of TBI. A total of 55 (63%) patients have died, 32 (36%) within the 1st year after BMT. In the 1st year, pulmonary events were reported for 24 (27%) patients, and the follow-up notes were unavailable for seven (8%). Pulmonary toxicities were reported as the cause of death for six patients, five (6%) within the 1st year. It is estimated that the total number of deaths in the 1st year possibly attributed to radiation-induced lung injury was four (4·5%). Eight (9%) patients had symptoms suggestive of non-lethal grade 2–3 radiation-induced pneumonitis.

Conclusions

TBI continues to be an important component of the conditioning regimen for ALL patients undergoing BMT, and the incidence of radiation-induced pulmonary injury, using our technique and lung dose, is comparable to the published literature.

Effectiveness of fludarabine- and busulfan-based conditioning regimens in patients with acute myeloblastic leukemia: 8-year experience in a single center

OBJECTIVE

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment for acute myeloblastic leukemia (AML). Because the conditioning regimen of busulfan plus cyclophosphamide carries significant risks of toxicity, we evaluated the factors affecting survival after fludarabine replacement instead of cyclophosphamide.

METHODS

The study included 55 patients who underwent allo-HSCT for AML and received busulfan, fludarabine, and antithymocyte globulin (ATG).

RESULTS

Forty-eight patients received a myeloablative regimen; 7 patients received a reduced-intensity conditioning regimen. The neutrophil and platelet engraftment times were 12 days (range 9 to 20) and 12 days (range 7 to 19), respectively. Graft-vs-host disease (GvHD) developed in 10% and 50% of the patients, respectively. Seven patients received donor lymphocyte infusion. Of them, 5 patients developed grade I or II GvHD, one grade IV GvHD. The median follow-up period was 20.6 months. The predicted progression-free survival (PFS) at 1 and 3 years after transplantation was 78% and 74%, respectively. The overall survival (OS) at 1, 3, and 5 years was 76%, 74%, and 62%, respectively. Treatment-related mortality (infection in 1 patient, GvHD in 2 patients) occurred in 3 patients (5.5%). Multivariate analysis revealed that OS and PFS were not influenced by age, dose of busulfan or ATG, or presence of cytomegalovirus antigenemia. Acute GvHD and pretransplantation minimal residual disease positivity negatively affected the transplant outcome. The presence of active disease at the time of transplantation was found as an independent risk factor for AML.

CONCLUSIONS

Busulfan- and fludarabine-based conditioning regimens are effective for AML, and have acceptable toxicity, morbidity, and mortality.

Comparison of outcomes of allogeneic transplantation for chronic myeloid leukemia with cyclophosphamide in combination with intravenous busulfan, oral busulfan, or total body irradiation

Cyclophosphamide (Cy) in combination with busulfan (Bu) or total body irradiation (TBI) is the most commonly used myeloablative conditioning regimen in patients with chronic myeloid leukemia (CML). We used data from the Center for International Bone Marrow Transplantation Research to compare outcomes in adults who underwent hematopoietic cell transplantation for CML in first chronic phase after myeloablative conditioning with Cy in combination with TBI, oral Bu, or intravenous (i.v.) Bu. Four hundred thirty-eight adults received human leukocyte antigen (HLA)-matched sibling grafts and 235 received well-matched grafts from unrelated donors (URD) from 2000 through 2006. Important differences existed between the groups in distribution of donor relation, exposure to tyrosine kinase inhibitors, and year of transplantation. In multivariate analysis, relapse occurred less frequently among patients receiving i.v. Bu compared with TBI (relative risk [RR], .36; P = .022) or oral Bu (RR, .39; P = .028), but nonrelapse mortality and survival were similar. A significant interaction was detected between donor relation and the main effect in leukemia-free survival (LFS). Among recipients of HLA-identical sibling grafts, but not URD grafts, LFS was better in patients receiving i.v. Bu (RR, .53; P = .025) or oral Bu (RR, .64; P = .017) compared with TBI. In CML in first chronic phase, Cy in combination with i.v. Bu was associated with less relapse than TBI or oral Bu. LFS was better after i.v. or oral Bu compared with TBI.

Reduced-toxicity conditioning prior to allogeneic stem cell transplantation improves outcome in patients with myeloid malignancies

The introduction of reduced intensity/toxicity conditioning regimens has allowed allogeneic hematopoietic cell transplantation to be performed in patients who were previously considered too old or otherwise unfit. Although it led to a reduction in non-relapse mortality, disease control remains a major challenge. We studied the outcome of 165 patients with acute myeloid leukemia (n=124) or myelodysplastic syndrome (n=41) transplanted after conditioning with fludarabine (30 mg/m(2)/day for 5 days), intravenous busulfan (either 260 mg/m(2): reduced intensity conditioning, or 390-520 mg/m(2): reduced toxicity conditioning), and rabbit anti-thymoglobulin (2.5 mg/kg/day for 2 days). The median age of the patients at transplantation was 56.8 years. The 2-year relapse incidence was 29% (23% versus 39% for patients transplanted in first complete remission and those transplanted beyond first complete remission, respectively; P=0.008). The 2-year progression-free survival rate was 57% (95% CI: 49.9-65). It was higher in the groups with favorable or intermediate cytogenetics than in the group with unfavorable cytogenetics (72.7%, 60.5%, and 45.7%, respectively; P=0.03). The cumulative incidence of grades 2-4 and 3-4 acute graft-versus-host disease at day 100 was 19.3% and 7.9%, respectively. The cumulative incidence of chronic graft-versus-host disease at 1 year was 21.6% (severe forms: 7.8%). Non-relapse mortality at 1 year reached 11%. The 2-year overall survival rate was 61.8% (95% CI: 54.8-69.7). Unfavorable karyotype and disease status beyond first complete remission were associated with a poorer survival. This well-tolerated conditioning platform can lead to long-term disease control and offers possibilities of modulation according to disease stage or further development.

Complications of allogeneic hematopoietic stem cell transplantation

Infection, graft-versus-host disease (GVHD), and to a lesser extent sinusoidal obstructive syndrome (SOS) represent the major causes of morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplantation (AHSCT). During the last decade, progress in prevention and treatment of these complications led to improvement in the outcome of these patients. Despite the fact that nonmyeloablative regimens have been increasingly used in elderly patients and in patients with co-morbidities, the nonrelapse related mortality remains a challenge and long-term follow-up is required. The objective of this manuscript is to provide an updated concise review of the complications of AHSCT and of the available treatment interventions.

Management of patients with hepatitis B who require immunosuppressive therapy

Patients with chronic HBV infection are at risk of reactivation of HBV should they require immunosuppressive therapies for a variety of clinical settings, including chemotherapy for patients with cancer, immunosuppression for solid organ and stem cell transplant recipients, and use of anti-CD20 antibodies, TNF inhibitors, or corticosteroids in patients with oncological, gastrointestinal, rheumatological or dermatological conditions. The key to preventing HBV reactivation is the identification of patients with HBV infection prior to immunosuppressive therapy, initiation of prophylactic antiviral therapy in patients at moderate or high risk of HBV reactivation, and close monitoring of other patients so that antiviral therapy can be initiated at the first sign of HBV reactivation. Unfortunately, many patients infected with HBV are unaware of their infection or risk factors, and physicians often do not have sufficient time to systematically assess patients for risk factors for HBV prior to starting immunosuppressive therapy. In this article, we review the incidence, risk factors and outcomes of HBV reactivation, and the efficacy of antiviral therapy in preventing its occurrence. We also propose an algorithm for managing patients with HBV infection who require immunosuppressive therapy.

Better leukemia-free and overall survival in AML in first remission following cyclophosphamide in combination with busulfan compared with TBI

Cyclophosphamide combined with total body irradiation (Cy/TBI) or busulfan (BuCy) are the most widely used myeloablative conditioning regimens for allotransplants. Recent data regarding their comparative effectiveness are lacking. We analyzed data from the Center for International Blood and Marrow Transplant Research for 1230 subjects receiving a first hematopoietic cell transplant from a human leukocyte antigen-matched sibling or from an unrelated donor during the years 2000 to 2006 for acute myeloid leukemia (AML) in first complete remission (CR) after conditioning with Cy/TBI or oral or intravenous (IV) BuCy. Multivariate analysis showed significantly less nonrelapse mortality (relative risk [RR] = 0.58; 95% confidence interval [CI]: 0.39-0.86; P = .007), and relapse after, but not before, 1 year posttransplant (RR = 0.23; 95% CI: 0.08-0.65; P = .006), and better leukemia-free survival (RR = 0.70; 95% CI: 0.55-0.88; P = .003) and survival (RR = 0.68; 95% CI: 0.52-0.88; P = .003) in persons receiving IV, but not oral, Bu compared with TBI. In combination with Cy, IV Bu is associated with superior outcomes compared with TBI in patients with AML in first CR.

Maximum supportive care, standard conditioning and allogeneic stem cell transplantation for elderly patients with acute myelogenous leukemia

Dose-intense conditioning (DIC) (myeloablative) regimens for allogeneic stem cell transplantation (alloSCT) were previously avoided in patients with acute myelogenous leukemia aged more than 55 years because of the fear of excessive morbidity and mortality. The introduction of reduced-intensity conditioning (RIC) alloSCT led to their increasing use in these patients because of their reduced toxicity. Significant disadvantages remain, however, including the late establishment of a posttransplant graft-versus-leukemia effect and an overrepresentation of poor prognostic factors in elderly patients, resulting in the risk of early relapse/progression before the graft-versus-leukemia effect being disproportionally large. Preliminary results suggest that DIC with maximum prophylaxis and support is safe for elderly patients up to age 70 years. We hypothesize that DIC may be important for the early control of leukemia in elderly patients, and that prospective, randomized trials comparing DIC and RIC-based transplants should be carried out, with the expectation that early transplant-related mortality will be no different.

Different behavior of SCE-eliciting lesions induced by low and high doses of busulfan

Our previous studies suggested a dose-dependent transition in the types of DNA lesions induced by busulfan, as measured using the comet assay and by micronuclei analyses. The aim of the present study was to investigate the dose-dependent induction of different sister-chromatid exchange-eliciting lesions; lesions were distinguished by their efficiency in producing sister-chromatid exchange (SCE), and by their reparability during G1. Synchronously dividing murine salivary gland cells were assayed in vivo. Groups of mice were intraperitoneally injected with either 30 or 80 micromol busulfan/kg body weight solution at early or late G1. The rate of SCE/micromol busulfan/kg body weight obtained by exposure at late G1 with the high dose was twice that of the low dose. SCE induction during early G1 was higher than at late G1 with both doses; only the low-dose response was statistically significant. The frequency distribution of SCEs per cell demonstrated that cells exposed at the late G1 phase showed typical profiles that closely fit a Gaussian curve. However, an irregular profile was obtained for cells treated during early G1, which showed some cells with high-SCE frequency. Cells treated in early G1 have more time to repair lesions before DNA synthesis; therefore, the results suggest that instead of repair, secondary SCE-eliciting lesions during G1 were produced, especially at the lower dose. The results obtained in this study indicate that there are dose-dependent differences in the types of SCE-eliciting lesions induced by busulfan.

Reduced adiposity in ob/ob mice following total body irradiation and bone marrow transplantation

OBJECTIVE

The objective of this study was to assess long-term metabolic consequences of total body irradiation (TBI) and bone marrow transplantation. Severe obesity develops due to both hypertrophy and hyperplasia of adipocytes. We hypothesized that TBI would arrest adipose tissue growth and would affect insulin resistance (IR).

RESEARCH METHODS AND PROCEDURES

We exposed 2-month-old female ob/ob mice to 8 Grays of TBI followed by bone marrow transplantation and tested the animals for body weight (BW) gain, body composition, blood glucose, and insulin sensitivity.

RESULTS

Two months after TBI, irradiated mice stopped gaining BW, whereas non-treated mice continued to grow. At the age of 9.5 months, body mass of irradiated mice was 60.6 +/- 1.4 grams, which was only 61% of that in non-treated ob/ob controls (99.4 +/- 1.6 grams). Body composition measurements by DXA showed that decreased BW was primarily due to an impaired fat accumulation. This could not result from the production of leptin by bone marrow-derived adipocyte progenitors because inhibition of the obese phenotype was identical in recipients of both B6 and ob/ob bone marrow. Inability of the irradiated mice to accumulate fat was associated with hepatomegaly, lower levels of monocyte chemoattractant protein-1 expression in adipose tissue, and increased IR.

DISCUSSION

Our data argue in favor of the hypothesis that inability of adipose tissue to expand may increase IR. This mouse model may be valuable for studies of late-onset radiation-induced IR in humans.

Human immunodeficiency virus type 1 pathobiology studied in humanized BALB/c-Rag2-/-gammac-/- mice

The specificity of human immunodeficiency virus type 1 (HIV-1) for human cells precludes virus infection in most mammalian species and limits the utility of small animal models for studies of disease pathogenesis, therapy, and vaccine development. One way to overcome this limitation is by human cell xenotransplantation in immune-deficient mice. However, this has proved inadequate, as engraftment of human immune cells is limited (both functionally and quantitatively) following transplantation of mature human lymphocytes or fetal thymus/liver. To this end, a human immune system was generated from umbilical cord blood-derived CD34(+) hematopoietic stem cells in BALB/c-Rag2(-/-)gamma(c)(-/-) mice. Intrapartum busulfan administration followed by irradiation of newborn pups resulted in uniform engraftment characterized by human T-cell development in thymus, B-cell maturation in bone marrow, lymph node development, immunoglobulin M (IgM)/IgG production, and humoral immune responses following ActHIB vaccination. Infection of reconstituted mice by CCR5-coreceptor utilizing HIV-1(ADA) and subtype C 1157 viral strains elicited productive viral replication and lymphadenopathy in a dose-dependent fashion. We conclude that humanized BALB/c-Rag2(-/-)gamma(c)(-/-) mice represent a unique and valuable resource for HIV-1 pathobiology studies.

Reduced intensity conditioning prior to allogeneic stem cell transplantation for patients with acute myeloblastic leukemia as a first-line treatment

BACKGROUND

Thirty-three patients (median age 52; range 26-60) with acute myeloblastic leukemia (AML) were included in a pilot study of allogeneic stem cell transplantation (Allo-SCT) following a reduced-intensity conditioning (RIC).

METHODS

Patients achieving first complete remission (CR1) were selected for their high-risk clinical and/or leukemic features. All patients received two courses of consolidation chemotherapy including one high-dose cytarabine course. Among them, 13 patients in addition received a high-dose melphalan course followed by autologous SCT. Then, all patients received an RIC Allo-SCT combining fludarabine, busulfan, and antithymocyte globulin.

RESULTS

All patients engrafted had cumulative incidences of Gluksberg System Grade 2 acute and chronic graft-versus-host-disease (GVHD) of 24 (9-39%) and 64 (48-80%), respectively. Three patients died from nonrelapse causes (NRD) (cumulative incidence: 9%, 95% confidence interval (CI): 0-19) and 6 relapsed (cumulative incidence: 18%, 95% CI: 5-31). With a median follow-up of 18 months (range 7-52) after Allo-SCT, 26 patients are alive, of whom 24 remained in CR1 for a 2-year overall survival and leukemia-free survival (LFS) probabilities of 79 (range 61-90%) and 76 (range 59-87%), respectively. In a 'landmark' analysis starting on Day 100, the occurrence of chronic GVHD was associated with a lower relapse rate (0% vs. 44%: P = 0.007) and improved outcome (LFS; 95% vs. 53%, P = 0.007; overall survival, 95% vs. 61%, P = 0.05).

CONCLUSIONS

We conclude that the sequential combination of intensive chemotherapy and allogeneic immunotherapy might offer relatively low NRD and leukemia relapse rates even in high-risk patients.

High-dose busulfan, cyclophosphamide, and etoposide does not improve outcome of allogeneic stem cell transplantation compared to BuCy2 in patients with acute myeloid leukemia

SUMMARY

To reduce relapse following allogeneic transplantation for AML, intensification of high-dose busulfan/cyclophosphamide using additional agents has been investigated but with few reported comparisons. We compared an intensified regimen of etoposide (60 mg/kg), busulphan (14 mg/kg), and cyclophosphamide (120 mg/kg) (BuCyVP) with BuCy2 in 237 AML patients. No significant difference in overall outcome was observed following BuCyVP (n=127) or BuCy2 (n=110). The 5-year survival was 27.3 and 30.1% following BuCyVP and BuCy2, respectively (P=0.48). Similarly, the 5-year cumulative incidence of relapse (CIR) was 28.3 and 34.8% with BuCyVP and BuCy2 (P=0.45), respectively. On multivariable analysis, patients transplanted in CR1 (P=0.002) and from related donors (P=0.013) had longer survival, while disease status at transplant was the only factor predicting CIR (P=0.002). In a separate analysis of CR1 patients (n=56), there was no significant difference in survival (P=0.37) or CIR (P=0.87) between the two regimens. However, for more advanced disease, there was a trend towards less relapse with BuCyVP (P=0.08), which was balanced by a higher cumulative incidence of transplant-related deaths (P=0.03) compared to BuCy2, resulting in similar survival. Overall, our results do not support the use of the more intensive BuCyVP regimen over BuCy2 in either early or more advanced disease AML patients.

Hematologic aspects of myeloablative therapy and bone marrow transplantation

The transplantation of bone marrow cells or isolated hematopoietic stem cells from the bone marrow or peripheral blood is a widely utilized form of therapy for patients with incurable diseases of the hematopoietic and immune systems. Successful engraftment of the transplanted stem cells in an adequately prepared recipient normally leads to bone marrow reconstitution over a period of several weeks, accompanied by more gradual reconstitution of the immune system. Since the recipient is profoundly ill during the initial treatment period, laboratory data is critical for monitoring engraftment, detecting residual/recurrent disease, and identifying problems that may delay bone marrow reconstitution or lead to other medical complications. Accurate blood cell counts are imperative, and most bone marrow transplantation patients undergo periodic monitoring with bone marrow aspirates and biopsies with cytogenetic, molecular, and multiparametric flow cytometric studies. The potential complications of bone marrow transplantation include engraftment failure and delayed engraftment, infection, residual bone marrow disease, acute and chronic graft versus host disease, myelofibrosis, therapy-related acute leukemia, post-transplant lympho-proliferative disorders, and toxic myelopathy.

Posttransplant hematopoiesis in patients undergoing sibling allogeneic stem cell transplantation reflects that of their respective donors although with a lower functional capability

We tested the principle of whether patient long-term hematopoiesis following allogeneic stem cell transplantation (allo-SCT) reflects the characteristics of the hematopoiesis of their respective donor. For this purpose, we analyzed bone marrow (BM) hematopoiesis using long-term cultures (LTC), delta assays, and clonogeneic assays as well as CD34+ cells and their subsets by flow cytometry in a series of 37 patients undergoing allo-SCT, and we compared it to that of their respective human leukocyte antigen-matched sibling donors in a paired study performed more than 1 year after the transplant procedure. Interestingly, the main factor that influenced post-allo-SCT BM hematopoiesis in the long term was donor hematopoiesis. Nevertheless, compared to their respective donors, patients exhibited a significantly lower number of colony-forming units granulomonocytic, burst-forming units erythroid, and immature progenitors (CD34++/CD38dim/CD90+/CD133+ cells, LTC-initiating cells, and colonies generated in the delta assay). Moreover, BM stromal function was diminished in patients undergoing allo-SCT compared to their donors. In addition, the presence of chronic graft-versus-host disease under immunosuppressive treatment also conditioned an impaired hematopoietic function. In summary, our study shows that BM hematopoiesis evaluated more than 1 year after an allo-SCT mainly reproduces that of their respective donors, although with a significantly decreased in vitro activity.

Effectiveness of prophylactic Anti-HBV therapy in allogeneic hematopoietic stem cell transplantation with HBsAg positive donors

Use of hepatitis B surface antigen (HBsAg) positive donors for allogeneic hematopoietic stem cell transplantation (HSCT) causes serious hepatitis B virus (HBV)-related liver morbidity and mortality in the recipient. We compared the effectiveness of anti-HBV therapy in 29 recipients who underwent HSCT using HBsAg positive marrow (group I) against a historical control group of 25 patients who received HBsAg positive marrow without pre-HSCT prophylaxis (group II). Anti-HBV therapy consisted of lamivudine for HBsAg-positive donors and all recipients (n = 29) as well as HBV vaccination to all HBsAg-negative recipients (n = 10) before HSCT. After transplantation, HBV-related hepatitis was significantly higher in group II than group I recipients [12 of 25 recipients (48%) vs. 2 of 29 recipients (6.9%), p = 0.002] and in recipients whose donors had detectable serum HBV DNA by Digene Hybrid Capture II assay [8 of 14 recipients (57.1%) vs. 6 of 40 recipients (15.0%), p = 0.02]. Six recipients in group II and none in group I died of HBV-related hepatic failure (24.0% vs. 0%, p = 0.01). By multivariate Cox analysis, anti-HBV therapy effectively reduces post-HSCT HBV-related hepatitis (p = 0.01, adjusted hazards ratio 7.27, 95%CI 1.62-32.58). Our data support the use of prophylactic therapy in preventing HBV-related hepatitis after allogeneic HSCT from HBsAg-positive donor.

The role of reduced intensity conditioning allogeneic stem cell transplantation in patients with acute myeloid leukemia: a donor vs no donor comparison

Using a genetic randomization through a 'donor' vs 'no donor' comparison, the aim of this analysis was to assess the real benefit of reduced intensity conditioning allogeneic stem cell transplantation (RIC-allo-SCT) among 95 adult high-risk acute myeloid leukemia (AML) patients. In an 'intention-to-treat' analysis, leukemia-free survival (LFS) was significantly higher in the 'donor' group as compared to the 'no donor' group (P=0.01; 54 vs 30% at 4 years). The latter held true when restricting the analysis to the 25 patients who could actually receive the RIC-allo-SCT (P=0.001). Overall transplant-related mortality in the 'transplant' group was 12%, with overall survival (OS) being significantly higher in the 'transplant' group as compared to the 'no transplant' group (P=0.01). Also, in the 'intention-to-treat' analysis, OS was significantly higher in the 'donor' group as compared to the 'no donor' group (P=0.04). In the multivariate analysis, actual performance of RIC-allo-SCT (P=0.001; RR=4.0; 95% CI, 1.7-9.6) was the strongest factor significantly predictive of an improved LFS. We conclude that if a matched related donor is identified, RIC-allo-SCT should be proposed for AML patients not eligible for standard myeloablative allo-SCT.

High-dose treosulfan in patients with relapsed or refractory high-grade lymphoma receiving tandem autologous blood stem cell transplantation

This phase I/II study evaluated high-dose treosulfan in patients with high-grade lymphoma. In all, 21 patients (median age 51, 25-60 years) with primary refractory disease (n=3) or early (n=11) or late (n=7) relapse received DexaBEAM and one course etoposide for cytoreduction and PBPC mobilization. Subsequently, 16 patients received 30 g/m2 treosulfan and 140 mg/m2 melphalan, followed by autologous transplantation. Nine patients received a 2nd high-dose treatment (HDT) with 30 g/m2 treosulfan and 750 mg/m2 thiotepa. Recovery time to >1/nl leukocytes and >25/nl thrombocytes was 8.9 (range 8-11) and 11.9 (8-16) days after 1st and 9.6 (7-13) and 13 (9-19) days after 2nd HDT. Reversible grade 3 or 4 nonhematologic toxicities included mucositis (n=7), infection (n=7) and one episode of re-entry tachycardia. Two treatment-related deaths occurred after 2nd HDT. Since three dose-limiting toxicities occurred among nine patients receiving tandem HDT, 30 g/m2 of treosulfan was considered MTD in this setting. Patients with late compared to early relapse or refractory disease had a higher probability of CR (6/7 vs 3/14 patients, P=0.017) and overall survival (71 vs 21%, P<0.05, 24-49 months follow-up). In conclusion, high-dose treosulfan as major therapy component induces sustained complete remissions in relapsed high-grade lymphoma with acceptable toxicity.

Once-daily intravenous busulfan and fludarabine: clinical and pharmacokinetic results of a myeloablative, reduced-toxicity conditioning regimen for allogeneic stem cell transplantation in AML and MDS

Postulating favorable antileukemic effect with improved safety, we used intravenous busulfan and fludarabine as conditioning therapy for allogeneic hematopoietic stem cell transplantation (HSCT) for acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS). Fludarabine 40 mg/m2 and intravenous busulfan 130 mg/m2 were given once daily for 4 days, with tacrolimus-methotrexate as graft-versus-host disease (GVHD) prophylaxis. We treated 74 patients with AML and 22 patients with MDS; patients had a median age of 45 years (range, 19-66 years). Only 20% of the patients were in first complete remission (CR) at transplantation. Donors were HLA-compatible related (n = 60) or matched unrelated (n = 36). The CR rate for 54 patients with active disease was 85%. At a median follow-up of 12 months, 1-year regimen-related and treatment-related mortalities were 1% and 3%, respectively. Two patients had reversible hepatic veno-occlusive disease. Actuarial 1-year overall survival (OS) and event-free survival (EFS) were 65% and 52% for all patients, and 81% and 75% for patients receiving transplants in CR. Recipient age and donor type did not influence OS or EFS. Median busulfan clearance was 109 mL/min/m2 and median daily area-under-the-plasma-concentration-versus-time-curve was 4871 micromol-min, with negligible interdose variability in pharmacokinetic parameters. The results suggest that intravenous busulfan-fludarabine is an efficacious, reduced-toxicity, myeloablative-conditioning regimen for patients with AML or MDS undergoing HSCT.