Reduced-toxicity conditioning with fludarabine, BCNU, and melphalan in allogeneic hematopoietic cell transplantation: particular activity against advanced hematologic malignancies

Comparative analysis of reduced toxicity conditioning regimens between fludarabine plus melphalan and fludarabine plus busulfex in adult patients with acute lymphoblastic leukemia

Reduced-toxicity conditioning (RTC) regimens aim to mitigate regimen-related toxicity while maintaining anti-leukemic efficacy in allogeneic hematopoietic stem cell transplantation (allo-HSCT). We assessed outcomes of RTC regimens utilizing melphalan versus intravenous busulfan combined with fludarabine in adult acute lymphoblastic leukemia (ALL) patients. A retrospective analysis was conducted with 149 consecutive adult ALL patients (median age 51, range 18-60) in remission undergoing allo-HSCT. Patients received either fludarabine 150 mg/BSA plus 2 days of melphalan 70 mg/BSA (FM140, n = 76) from 2009 to 2015 or fludarabine plus 3 days of busulfan 3.2 mg/kg (FB9.6, n = 73) from 2016 to 2021. At 5 years post-HSCT, FM140 demonstrated superior disease-free survival (53.4% vs. 30.5%, p = 0.007) and lower cumulative relapse (27.4% vs. 46.8%, p = 0.026) than FB9.6. Five-year overall survival and non-relapse mortality did not significantly differ. FM140 exhibited a higher incidence of acute graft-versus-host disease (GVHD) grades II-IV (49.3% vs. 30.3%, p = 0.016), though rates of acute GVHD grades III-IV and chronic GVHD were similar. Multivariate analysis identified Philadelphia chromosome and minimal residual disease positive status, and FB9.6 conditioning as predictors of increased relapse and poorer disease-free survival. FM140 RTC regimen displayed significantly reduced relapse and superior disease-free survival compared to FB9.6 in ALL patients undergoing allo-HSCT, highlighting its current clinical utility.

Management of post-autologous transplant relapse in patients with T-cell lymphomas

Autologous hematopoietic cell transplantation (AHCT) is often used as a consolidation for patients with peripheral T-cell lymphomas (PTCLs) due to the poor prognosis associated with this heterogenous group of disorders. However, a significant number of patients will experience post-AHCT disease relapse. Here, we report a retrospective study of consecutive 124 patients with PTCLs who underwent AHCT from 2008 to 2020. With a median follow-up of 6.01 years following AHCT, 49 patients (40%) experienced disease relapse. As expected, more patients who were not in first complete remission experienced post-AHCT relapse. Following relapse, majority of the patients (70%) receiving systemic therapies intended as bridging to curative allogeneic HCT. However, only 18 (53%) patients eventually underwent allogeneic HCT. The estimated 3-year OS among patients proceeding to allogeneic HCT was 72% (95% CI 46%-87%). Our report details the pattern of post-AHCT relapse and the management of relapsed disease using different therapeutic modalities.

Comparison of fludarabine/melphalan (FluMel) with fludarabine/melphalan/BCNU or thiotepa (FBM/FTM) in patients with AML in first complete remission undergoing allogeneic hematopoietic stem cell transplantation - a registry study on behalf of the EBMT Acute Leukemia Working Party

Conditioning protocols for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) are being developed continuously to improve their anti-leukemic efficacy and reduce their toxicity. In this study, we compared the conditioning protocol of fludarabine with melphalan 140 mg/m2 (FluMel) with conditioning protocols based on this same backbone but with an additional alkylating agent i.e., either fludarabine/BCNU (also known as carmustine)/melphalan (FBM), or fludarabine/thiotepa/melphalan (FTM) 110 mg/m2. We included 1272 adult patients (FluMel, n = 1002; FBM/FTM, n = 270) with acute myeloid leukemia (AML) with intermediate/poor cytogenetic risk in first complete remission (CR) from the registry of the EBMT Acute Leukemia Working Party. Despite patients in the FBM/FTM group were older (64.1 years vs. 59.8 years, p < 0.001) and had a worse Karnofsky performance score (KPS < 90, 33% vs. 24%, p = 0.003), they showed a better overall survival (OS) (2 y OS: 68.3% vs. 58.1%, p = 0.02) and less non-relapse mortality (NRM) (2 y NRM: 15.8% vs. 22.2%, p = 0.009) compared to patients treated with FluMel. No significant differences were observed in relapse incidence (RI) (2 y RI: 24.9% vs. 23.7%, p = 0.62). In conclusion, the addition of a second alkylating agent (BCNU/carmustine or thiotepa) to FluMel as FBM/FTM conditioning, improves OS in AML patients in first CR with intermediate/poor risk cytogenetics after allo-HCT.

Long-term outcomes of corticosteroid graft versus host disease prophylaxis in peripheral blood allogeneic haemopoietic stem cell transplant: a comparative cohort analysis

BACKGROUND

Corticosteroids (CSs) have previously been incorporated into graft versus host disease (GVHD) prophylaxis regimens for bone marrow (BM) and haemopoietic stem cell transplant (HSCT).

AIMS

To assess the impact of prophylactic CS in HSCT using peripheral blood (PB) stem cells.

METHODS

Patients were identified from three HSCT centres receiving a first PB-HSCT between January 2011 and December 2015 from a fully human leukocyte antigen (HLA)-matched sibling or unrelated donor for acute myeloid leukaemia or acute lymphoblastic leukaemia. To enable meaningful comparison, patients were divided into two cohorts.

RESULTS

Cohort 1 included only myeloablative-matched sibling HSCT, where the only variation in GVHD prophylaxis was the addition of CS. In these 48 patients, there were no differences in GVHD, relapse, non-relapse mortality, overall survival or GVHD-relapse-free-survival (GRFS) at 4 years after transplant. Cohort 2 included the remaining HSCT recipients, where one group received CS-prophylaxis and the non-CS group received an antimetabolite, ciclosporin and anti-T-lymphocyte globulin. In these 147 patients, those receiving CS-prophylaxis experienced higher rates of chronic GVHD (71% vs 18.1%, P < 0.001) and lower rates of relapse (14.9% vs 33.9%, P = 0.02). Those receiving CS-prophylaxis had a lower 4-year GRFS (15.7% vs 40.3%, P = 0.002).

CONCLUSIONS

There does not appear to be a role for adding CS to standard GVHD prophylaxis regimens in PB-HSCT.

Cardiovascular events among recipients of hematopoietic stem cell transplantation-A systematic review and meta-analysis

Cardiovascular diseases are an emerging cause of mortality and morbidity in survivors of hematopoietic stem cell transplantation (HSCT); however, the incidence of cardiovascular events (CVEs) in this population is not well described. This systematic review summarizes the evidence on the incidence of CVEs in HSCT recipients. Medline and Embase were searched from inception to December 2020. Inclusion criteria were cohort studies and phase 3 randomized controlled trials that reported CVEs among adults who underwent HSCT for hematological malignancies. After reviewing 8386 citations, 57 studies were included. The incidence of CVEs at 100 days was 0.19 (95% CI: 0.17-0.21) per 100 person-days after autologous HSCT and 0.06 (95% CI: 0.05-0.07) per 100 person-days after allogeneic HSCT. This higher incidence after autologous HSCT was driven by reports of arrhythmia from one population-based study in patients with multiple myeloma. The incidence of long-term CVEs was 3.98 (95% CI; 3.44-4.63) per 1000 person-years in survivors of autologous HSCT and 3.06 (95% CI; 2.69-3.48) per 1000 person-years in survivors of allogeneic HSCT. CVEs remain an important but under-reported cause of morbidity and mortality in recipients of HSCT. Future studies are required to better understand the incidence and risk factors for CVEs in HSCT recipients.

Haploidentical versus Double-Cord Blood Stem Cells as a Second Transplantation for Relapsed Acute Myeloid Leukemia

There are limited data on second stem cell transplantation (SCT2) outcomes with alternative donors for relapsed AML after the first stem cell transplantation (SCT1). We analyzed the outcomes of 52 adult AML patients who received SCT2 from haploidentical donors (HIT, N = 32) and double-cord blood (dCBT, N = 20) between 2008 and 2021. The HIT group received T-cell-replete peripheral blood stem cells after reduced-toxicity conditioning with anti-thymocyte globulin (ATG), while the dCBT group received myeloablative conditioning. For a median follow-up of 64.9 months, the HIT group, compared to the dCBT group, had earlier engraftment, superior 2-year overall survival (OS), disease-free survival (DFS), and non-relapse mortality (NRM) with similar relapse. Multivariate analysis demonstrated that HIT was significantly associated with better OS, DFS, and lower NRM than dCBT. Both longer remission duration after SCT1 and complete remission at SCT2 were significantly associated with a lower relapse rate. In addition, bone marrow WT1 measurable residual disease (MRD) positivity was significantly associated with inferior OS and higher relapse. This study suggests that T-cell-replete HIT with ATG-based GVHD prophylaxis may be preferred over dCBT as SCT2 for relapsed AML and that WT1-MRD negativity may be warranted for better SCT2 outcomes.

Allogeneic transplantation for advanced acute leukemia

Outcomes of allogeneic hematopoietic cell transplantation (HCT) for patients with advanced acute leukemia and myelodysplastic syndromes (MDS) remain uncertain. All published series include the important and often not stated selection bias that influences outcome. Performance status, patient age, prompt donor availability, risk phenotype of the leukemia, and tumor burden all influence the decision-making process about HCT with active disease. In addition, patients with MDS do not achieve a true pre-HCT complete remission, and thus much less stringent measures are used to indicate suitability for allografting in that disease. Post-HCT maintenance or investigational approaches for tumor depletion may improve the outcomes.

The impact of Rituximab administered before transplantation in patients undergoing allogeneic hematopoietic stem cell transplantation: A real-world study

Rituximab is used to eliminate B cells as a chimeric monoclonal antibody directed against CD20, a B-cell antigen expressed on B cells. To explore the impact of rituximab administered before transplantation, we implemented a retrospective, monocentric study and utilized real-world data collected at our center between January 2018 and December 2020, and then followed until December 2021. Based on whether a dose of 375mg/m2 rituximab was used at least once within two weeks before transplantation, patients undergoing allo-HSCT were classified into two groups: rituximab (N=176) and non-rituximab (N=344) group. Amongst all the patients, the application of rituximab decreased EBV reactivation (P&lt;0.01) and rituximab was an independent factor in the prevention of EBV reactivation by both univariate and multivariate analyses (HR 0.56, 95%CI 0.33-0.97, P=0.04). In AML patients, there were significant differences in the cumulative incidence of aGVHD between the two groups (P=0.04). Our data showed that rituximab was association with a decreased incidence of aGVHD in AML patients according to both univariate and multivariate analyses. There was no difference between the two groups in other sets of populations. Thus, our study indicated that rituximab administered before transplantation may help prevent EBV reactivation in all allo-HSCT patients, as well as prevent aGVHD in AML patients after allo-HSCT.

Monitoring of Measurable Residual Disease Using Circulating DNA after Allogeneic Hematopoietic Cell Transplantation

Simple Summary

The major cause of treatment failure after allogeneic stem cell transplantation (allo-HSCT) is due to relapse of the underlying disease. Novel methods and strategies are needed to detect early relapse after allo-HSCT. The present study reports the clinical utility of monitoring measurable residual disease (MRD) and mixed chimerism (MC) by droplet-digital PCR in circulating cell-free DNA (cfDNA) in 62 patients with myeloid malignancies undergoing allo-HSCT. MC in circulating cfDNA at an optimal threshold of 18% discriminated patients with hematological relapse from patients in complete remission after allo-HSCT. Most of the mutations identified using a targeted next-generation sequencing (NGS) panel were detected in cfDNA at relapse and were suitable for the monitoring of MRD. In several cases, mutations were detected earlier in cfDNA than in peripheral blood mononuclear cells. In conclusion, longitudinal analysis of cfDNA for MRD and MC can be used as a complementary tool for early detection of relapse in patients after allo-HSCT and could be used to guide clinical interventions.

Abstract

Relapse of the underlying disease is a frequent complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). In this study, we describe the clinical utility of measurable residual disease (MRD) and mixed chimerism (MC) assessment in circulating cell-free DNA (cfDNA) analysis to detect earlier relapse in patients with hematological malignancies after allo-HSCT. A total of 326 plasma and peripheral blood mononuclear cell (PBMCs) samples obtained from 62 patients with myeloid malignancies were analyzed by droplet-digital PCR (median follow-up: 827 days). Comparison of MC in patients at relapse and in complete remission identified an optimal discriminating threshold of 18% of recipient-derived cfDNA. After performing a targeted next-generation sequencing (NGS) panel, 136 mutations in 58 patients were detected. In a total of 119 paired samples, the putative mutations were detected in both cfDNA and PBMCs in 73 samples (61.3%). In 45 samples (37.8%) they were detected only in cfDNA, and in only one patient (0.9%) were they detected solely in DNA from PBMCs. Hence, in 6 out of 23 patients (26%) with relapse after allo-HSCT, MRD positivity was detected earlier in cfDNA (mean 397 days) than in DNA derived from PBMCs (mean 451 days). In summary, monitoring of MRD and MC in cfDNA might be useful for earlier relapse detection in patients with myeloid malignancies after allo-HSCT.

Rehabilitation after Allogeneic Haematopoietic Stem Cell Transplantation: A Special Challenge

Simple Summary

After undergoing an allogeneic haematopoietic stem cell transplantation (alloHCT), patients need intensive physiological and psychological rehabilitation. This should start immediately after discharge from the transplant ward as in- or outpatient rehabilitation. The rehabilitation centres should be qualified and experienced because this patient group exhibits problems that differ from those of patients who have undergone oncological therapies or autologous HCT. An experienced multidisciplinary team in close consultation with the primary transplantation centre should perform the rehabilitation therapy. This review will show the special challenges of these patients according to different timepoints after HCT. Because there is so little data available, personal experience and general guidelines on patient care after alloHCT are presented.

Abstract

The general population is getting older and suffer more haematological malignancies despite being physically fit. These malignancies are mainly only curable via an alloHCT, and they are now carried out more frequently. Patients benefit from intensive rehabilitation earlier and may need it repeatedly in cases of severe side effects (e.g., graft-versus-host disease). They can suffer many problems that other cancer patients do not experience, such as severe infections, continued immunosuppression, nutritional restrictions, acute or chronic GvHD, or organ impairments (e.g., lung, eyes). They may also encounter various associated psychological problems, e.g., feeling like a chimera. Rehabilitation centres willing to care for patients after alloHCT should have an experienced multidisciplinary team and should work in close co-operation with the primary transplant centre.

Dose intensity for conditioning in allogeneic hematopoietic cell transplantation: can we recommend "when and for whom" in 2021?

Allogeneic hematopoietic stem-cell transplantation is a potentially curative therapy for various hematologic diseases. An essential component of this procedure is the pre-transplant conditioning regimen, which should facilitate engraftment and reduce or eliminate tumor cells. The recognition of the substantial association of a graft-versus- tumor effect and the high toxicity of the commonly used conditioning regimen led to the introduction of more differentiated intensity strategies, with the aim of making hematopoietic stem-cell transplantation less toxic and safer, and thus more applicable to broader populations such as older or unfit patients. In general, prospective and retrospective studies suggest a correlation between increasing intensity and nonrelapse mortality and an inverse correlation with relapse incidence. In this review, we will summarize traditional and updated definitions for conditioning intensity strategies and the landscape of comparative prospective and retrospective studies, which may help to find the balance between the risk of non-relapse mortality and relapse. We will try to underscore the caveats regarding these definitions and analyses, by missing complex differences between intensity and toxicity as well as the broad influences of other factors in the transplantation procedure. We will summarize evidence regarding several confounders which may influence decisions when selecting the intensity of the conditioning regimen for any given patient, according to the individual risk of relapse and non-relapse mortality.

A prospective single-center study on CNI-free GVHD prophylaxis with everolimus plus mycophenolate mofetil in allogeneic HCT

We report a single-center phase I/II trial exploring the combination of everolimus (EVE) and mycophenolate mofetil (MMF) as calcineurin inhibitor (CNI)-free GVHD prophylaxis for 24 patients with hematologic malignancies and indication for allogeneic HCT after a high dose or reduced-intensity ablative conditioning. The study was registered as EudraCT-2007-001892-12 and Clinicaltrials.gov as NCT00856505. All patients received PBSC grafts and no graft failure occurred. 7/24 patients (29%) developed acute grades III and IV GVHD (aGVHD), 16/19 evaluable patients (84%) developed chronic GVHD (cGVHD) of all grades, and 6/19 (31.6%) of higher grades. No severe toxicities related to study medication were observed. The median follow-up of all surviving patients is 2177 days. The 3-year OS was 45.2% (95% CI: 27.4–61.4%), and the 3-year PFS was 38.7% (95% CI: 22.0–55.1%). The cumulative incidence of relapse at 1 year and 3 year was 25% (95% CI: 12.5–50.0%), and 33.3% (95% CI: 18.9–58.7%), the cumulative incidence of NRM at 1 year and 3 years was 20.8% (95%CI: 9.6–45.5%), and 29.2% (95%CI: 15.6–54.4%), respectively. The utilization of CNI-free GVHD prophylaxis with EVE+MMF resulted in high rates of acute and chronic GVHD. Therefore, we do not recommend a CNI-free combination of mTOR inhibitor EVE with MMF as the sole GVHD prophylaxis. In subsequent studies, this combination should be modified, e.g., with further components like post-transplant cyclophosphamide (PTCy) or anti-thymocyte globulin (ATG).

Hematopoietic stem cell transplantation in children and adolescents with nonremission acute lymphoblastic leukemia

BACKGROUND

The appropriateness of allogeneic hematopoietic stem cell transplantation (HSCT) in children and adolescents with leukemia in whom complete remission is not possible remains unclear. This retrospective analysis aimed to investigate the outcomes associated with HSCT, and the risks of HSCT in children and adolescents with nonremission acute lymphoblastic leukemia (ALL).

PROCEDURE

Data from the Japan Society for Hematopoietic Cell Transplantation registry on 325 patients with nonremission ALL (aged <21 years, with blasts in the peripheral blood and/or bone marrow) who had undergone HSCT between January 2001 and December 2015 were evaluated. To assess survival, we developed a scoring system using significant adverse pre-HSCT variables.

RESULTS

Overall, 247 patients died. The median length of follow up among survivors was 1145 days, and the 3-year overall survival was 22% (95% confidence interval [CI]: 18-27%). A low performance score, presence of >25% bone marrow blasts, T-cell phenotype, poor-risk or normal cytogenetics, and history of HSCT were predictors of a poor outcome. Patients scoring 0-1 (n = 109), 2 (n = 91), and 3-7 (n = 125) had a 3-year overall survival of 41% (95% CI: 31-51%), 21% (95% CI: 13-31%), and 7% (95% CI: 3-12%), respectively.

CONCLUSION

These results support HSCT in certain nonremission patients. Even in patients without complete remission, outcomes differed according to pre-HSCT factors. A scoring system could help determine the appropriateness of HSCT in children and adolescents with nonremission ALL.

Colon and liver tissue damage detection using methylated SESN3 and PTK2B genes in circulating cell-free DNA in patients with acute graft-versus-host disease

Cell-free DNA (cfDNA) has been investigated in acute graft-versus-host disease (aGvHD) following allogeneic cell transplantation (HSCT). Identifying the tissue of origin of cfDNA in patients with aGvHD is relevant particularly when a biopsy is not feasible. We investigate the cfDNA tissue of origin in patients with aGvHD using methylated gene biomarkers. Patients with liver, colon, or skin aGvHD (n = 28) were analyzed. Liver- and colon-derived cfDNA was measured using a colon- (SESN3) and liver (PTK2B)-specific methylation marker with digital droplet PCR. A statistically significant difference (p < 0.001) in PTK2B and SESN3 concentration was observed between patients with colon or liver GvHD and the control group. For SESN3 and PTK2B the area under the curve in the receiver-operating characteristic (ROC) space was 0.952 (95% CI, 0.888–1 p < 0.001) and 0.971 (95% CI, 0.964–1 p < 0.001), respectively. Thresholds to differentiate aGvHD from non-aGvHD in colon were 0 (sensitivity: 0.905; specificity: 0.989) and liver 1.5 (sensitivity: 0.928; specificity: 0.910). Clinical improvement of liver or colon aGvHD resulted in PTK2B and SESN3 reduced concentration. Whereas, in those patients without improvement the PTK2B and SESN3 level remained stable or increased. The PTK2B liver-specific marker and the SESN3 colon-specific marker and their longitudinal analysis might improve aGvHD detection.

1,25-dihydroxyvitamin-D3 but not the clinically applied marker 25-hydroxyvitamin-D3 predicts survival after stem cell transplantation

The serum level of 25-hydroxyvitamin-D3 is accepted as marker for a person’s vitamin D status but its role for the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) is controversially discussed. The impact of 1,25-dihydroxyvitamin-D3 on HSCT outcome, however, has never been studied. In a discovery cohort of 143 HSCT patients we repeatedly (day −16 to 100) measured 1,25-dihydroxyvitamin-D3 and in comparison the well-established marker for serum vitamin D status 25-hydroxyvitamin-D3. Only lower 1,25-dihydroxyvitamin-D3 levels around HSCT (day −2 to 7, peritransplant) were significantly associated with higher 1-year treatment-related mortality (TRM) risk (Mann–Whitney U test, P = 0.001). This was confirmed by Cox-model regression without and with adjustment for baseline risk factors and severe acute Graft-versus-Host disease (aGvHD; unadjusted P = 0.001, adjusted P = 0.005). The optimal threshold for 1,25-dihydroxyvitamin-D3 to identify patients at high risk was 139.5 pM. Also in three replication cohorts consisting of altogether 365 patients 1,25-dihydroxyvitamin-D3 levels below 139.5 pM had a 3.3-fold increased risk of TRM independent of severe aGvHD compared to patients above 139.5 pM (Cox-model unadjusted P < 0.0005, adjusted P = 0.001). Our data highlight peritransplant 1,25-dihydroxyvitamin-D3 levels but not the commonly monitored 25-hydroxyvitamin-D3 levels as potent predictor of 1-year TRM and suggest to monitor both vitamin D metabolites in HSCT patients.

Comparison of reduced-toxicity conditioning protocols using fludarabine, melphalan combined with thiotepa or carmustine in allogeneic hematopoietic cell transplantation

The age of patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) has increased during the last decades, mainly due to improved reduced-intensity/toxicity conditioning protocols. A reduced-intensity conditioning based on fludarabin, carmustin/BCNU and melphalan (FBM) has been previously developed at our institution. Since we observed detrimental effects in individual patients with compromised lung function, efforts have been made in order to replace BCNU by thiotepa (FTM) to reduce toxicity. In this study, we retrospectively analyzed the outcome, GvHD incidence, lung function and organ toxicity of patients with a median age of 62 years (range 21–79) transplanted for malignant disease (96.7%, 62.3% in intermediate/advanced disease stage) at our institution after conditioning with FBM (n = 136) or FTM (n = 105) between 2013 and 2017. Median follow-up was 868 days (range 0–2615). In multivariate analysis for overall survival, no difference was detected between both conditioning protocols in the presence of impaired lung function, age, lower performance, and liver disease previous allo-HCT. In the subgroup analysis, FTM was not inferior to FBM in patients with pulmonary disease prior allo-HCT, lymphoid malignancies, and higher comorbidity index. In conclusion, the reduced-intensity FBM and FTM conditioning protocols show adequate antineoplastic efficacy and are suitable for patients with impaired lung function.

Conditioning protocol based on fludarabin, melphalan combined with thiotepa (FTM) showed sufficient anti-neoplastic effect and is suitable for patients with impaired lung function prior allo-HCT.

Predictive Values of Early Suppression of Tumorigenicity 2 for Acute GVHD and Transplant-related Complications after Allogeneic Stem Cell Transplantation: Prospective Observational Study

Objective:

A soluble form of suppression of tumorigenicity 2 (sST2) has emerged as a biomarker for acute graft-versus-host disease (GVHD) and non-relapse mortality (NRM). We prospectively monitored sST2 levels during the early phase of hematopoietic stem cell transplantation (HSCT) and evaluated the clinical association with transplant-related complications including acute GVHD.

Materials and Methods:

Thirty-two adult Japanese patients who received a first allogeneic HSCT were enrolled in this study. Levels of sST2 were measured at fixed time points (pre-conditioning, day 0, day 14, day 21, and day 28).

Results:

The median age was 50.5 years (range=16-66). With a median follow-up of 21.5 months (range=0.9-35.4), 9 patients developed grade II-IV acute GVHD. Median sST2 levels on the day of HSCT were higher than baseline and reached the maximum value (92.7 ng/mL; range=0-419.7) on day 21 after HSCT. The optimal cut-off value of sST2 on day 14 for predicting grade II-IV acute GVHD was determined as 100 ng/mL by ROC analysis. The cumulative incidence of acute GVHD was 56.7% and 16.5% in the high- and low-sST2 groups, respectively (p<0.01). Multivariate analyses showed that high sST2 levels at day 14 were associated with a higher incidence of acute GVHD (hazard ratio=9.35, 95% confidence interval=2.92-30.0, p<0.01). The cumulative incidence of NRM was increased in the high-sST2 group (33% vs 0%, p<0.01), but all the patients died of non-GVHD complications. Among 6 patients in the high-sST2 group without grade II-IV GVHD, 5 patients developed veno-occlusive disease (VOD) and one also had thrombotic microangiopathy (TMA).

Conclusion:

The early assessment of sST2 after HSCT yielded predictive values for the onset of acute GVHD and other transplant-related complications including VOD and TMA.

Droplet digital PCR for the simultaneous analysis of minimal residual disease and hematopoietic chimerism after allogeneic cell transplantation

Background Minimal residual disease (MRD) and hematopoietic chimerism testing influences clinical decision and therapeutic intervention in patients after allogeneic stem cell transplantation (HSCT). However, treatment approaches to induce complete donor chimerism and MRD negativity can lead to complications such as graft-versus-host disease (GvHD) and marrow aplasia. Therefore, there is a need for comprehensive characterization of the molecular remission status after transplantation. Methods We analyzed 764 samples from 70 patients after HSCT for the simultaneous measurement of chimerism and molecular targets used for MRD testing with a digital PCR (dPCR) platform. Results Mixed chimerism (MC) was detected in 219 samples from 37 patients. The mean percentage of host derived DNA in these clinical samples was 4.3%. Molecular relapse with a positive MRD marker and/or increased WT1 expression was observed in 15 patients. In addition to WT1 overexpression, other MRD positive markers were: NPM1 (Type A, B, K), DNMT3A (R882H), MLL-PTD, IDH1 (R132H) and KRAS (G12S). Increasing MC was observed in 15 patients. This group of patients showed either a positive MRD marker, increased WT1 expression or both. Next, we analyzed whether MC or the molecular target for MRD was first detected. MC and MRD marker positivity in this group was first detected in six and two patients, respectively. In the remaining seven patients MC and MRD positivity was detected simultaneously. Conclusions The combination of MRD and chimerism markers in a dPCR platform represents a practical, sensitive and accurate diagnostic tool for the comprehensive assessment of the molecular remission status of patients undergoing HSCT.

[A clinical study of haploidentical hematopoietic stem cell transplantation in the treatment of pediatric patients with acquired severe aplastic anemia: single center experience]

目的

探讨单倍型造血干细胞移植（haplo-HSCT）治疗儿童获得性重型再生障碍性贫血（SAA）的疗效。

方法

回顾性分析2011年12月1日至2017年12月1日接受haplo-HSCT的59例SAA患者。

结果

①全部59例SAA患儿中男37例、女22例，中位年龄4.5（1.2~14.8）岁，中位体重43（12~80）kg；SAA-Ⅰ型47例，SAA-Ⅱ型12例，26例为极重型再生障碍性贫血（VSAA）；首次移植56例，二次移植3例。②预处理选用白消安+环磷酰胺+抗胸腺细胞球蛋白（ATG）方案或白消安+氟达拉滨+环磷酰胺+ATG方案；采用环孢素A（CsA）+霉酚酸酯+甲氨蝶呤方案预防急性GVHD；回输单个核细胞中位数为15.60（7.74~21.04）×10⁸/kg，CD34⁺细胞中位数为4.86（3.74~7.14）×10⁶/kg。③全部59例患儿均获得中性粒细胞和血小板植入。中性粒细胞植入中位时间为13（10~19）d，血小板植入中位时间为19（9~62）d。④Ⅰ~Ⅱ、Ⅲ/Ⅳ度急性GVHD发生率分别为45.76%（27/59）、13.56%（8/59），慢性GVHD发生率为8.47%（5/59）。巨细胞病毒血症发生率为59.32%（35/59）、EB病毒血症发生率为28.81%（17/59）。⑤中位随访时间30（8~80）个月，57例无病存活，2例死亡（均死于GVHD），5年总生存率、无失败生存率均为（96.4±2.5）%。

结论

haplo-HSCT是儿童SAA疗效较好的治疗方法。

G-CSF-primed haplo-identical HSCT with intensive immunosuppressive and myelosuppressive treatments does not increase the risk of pre-engraftment bloodstream infection: a multicenter case-control study

A multicenter retrospective study in 131 patients (44 females/87 males) with hematological disorders who underwent G-CSF-primed/haplo-identical (Haplo-ID) (n = 76) or HLA-identical (HLA-ID) HSCT (n = 55) from February 2013 to February 2016 was conducted to compare the incidence and risk factors for pre-engraftment bloodstream infection (PE-BSI). In the Haplo-ID group, 71/76 patients with high-risk (n = 28) or relapsed/refractory hematological malignancies (n = 43) received FA5-BUCY conditioning (NCT02328950). All received trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis. Blood cultures and catheter tip cultures were obtained to confirm the BSI. PE-BSI was detected in 24/131 HSCT patients (18/76 in Haplo-ID and 6/55 in HLA-ID) after 28 febrile neutropenic episodes. Among 28 isolates for the 24 patients, 21 (75%) were G^neg bacteria, 6 (21.4%) G^pos and 1 (3.6%) fungi. Bacteria sources were central venous line infection (7/29.2%), gastroenteritis (6/25%), lower respiratory tract infection (LRTI; 5/20.8%), perianal skin infection (4/16.7%), and unknown (2/8.3%). The duration of neutropenia (P = 0.046) and previous G^neg bacteremia (P = 0.037) were important risk factors by univariate analysis, while the type of HSCT was not. A trend of TMP-SMX-resistant BSI in both groups may be due to routine antibacterial prophylaxis strategies. Our data show that G-CSF-primed Haplo-ID HSCT did not increase the risk of PE-BSI, even with intensive immunosuppressive treatments.

Impact of Lung Function on Bronchiolitis Obliterans Syndrome and Outcome after Allogeneic Hematopoietic Cell Transplantation with Reduced-Intensity Conditioning

Lung function deterioration contributes to treatment-related morbidity and mortality in patients after allogeneic hematopoietic cell transplantation (allo-HCT). Better understanding of impaired lung function including bronchiolitis obliterans syndrome (BOS) as chronic manifestation of graft-versus-host disease (GVHD) might improve outcomes of patients after allo-HCT. To detect early pulmonary function test abnormalities associated with BOS incidence and outcome after allo-HCT, we performed a retrospective analysis of homogenous-treated 445 patients (median age, 61.9 years; range, 19 to 76 years) with a reduced intensity/toxicity conditioning protocol. The cumulative incidence of BOS was 4.1% (95% confidence interval [CI], 2.6 to 6.4) at 1 year and 8.6% (95% CI, 6.3 to 11.6) at 5 years after allo-HCT with a median follow-up of 43.2 months (range, 3.3 to 209 months). In multivariate analysis, pre-existence of moderate small airway disease reflected by decreased midexpiratory flows before allo-HCT was associated with increased risk for BOS development. In addition, severe small airway disease before allo-HCT and combined restrictive/obstructive lung disease at day +100 after allo-HCT were associated with higher risk for nonrelapse mortality (NRM) due mainly to pulmonary cause of death. In summary, we identified novel pulmonary function test abnormalities prior and after allo-HCT associated with BOS development and NRM. These findings might help to identify a risk population and result in personalized GVHD prophylaxis and preventive or early therapeutic interventions.

Comparison of reduced intensity conditioning regimens used in patients undergoing hematopoietic stem cell transplantation for myelofibrosis

The aim of this study is to compare clinical outcomes of patients who underwent allogeneic stem cell transplantation (HCT) for myelofibrosis with reduced intensity conditioning (RIC) using either Busulfan Fludarabine (BuFlu), Fludarabine Bis-chlorethyl-nitroso-urea/ carmustine Melphalan (FBM) or Fludarabine Melphalan (FluMel) regimens. Sixty-one patients were identified who underwent HCT with one of these RIC regimens. Overall survival (OS) was not different in the 3 groups. However, 100% donor chimerism was seen in more frequently at day +30 and day +100 in patients who received FBM or FluMel than BuFlu, in both CD3 and CD33 fractions. For instance, 100% donor chimerism in CD33 fraction was present in 100% patients in FBM cohort, 90% in FluMel cohort while 44% in BuFlu cohort at day +100. Acute graft-versus host disease, grade 2-4 and grade 3-4, was not statistically different in the 3 groups (BuFlu 47 and 35%, FBM 68 and 27%, FluMel 68 and 46%; p = 0.31 and 0.45). Relapses and non-relapse mortality was also not statistically significantly different. Our study shows similar OS with these 3 RIC regimens in myelofibrosis; although donor chimerism at day +30 and day +100 was better in patients who received FBM and FluMel.

Cell-free DNA characteristics and chimerism analysis in patients after allogeneic cell transplantation

Cell-free DNA (cfDNA) isolated from plasma or serum has received increasing interest for diagnostic applications in pregnancy, solid tumors and solid organ transplantation. The reported clinical usefulness of cfDNA obtained from plasma or serum in patients undergoing allogeneic cell transplantation (alloHSCT) is scarce.

OBJECTIVE

To analyze the potential clinical utility of cfDNA chimerism analysis after alloHSCT.

DESIGN AND METHODS

A total of 196 samples obtained from 110 patients were investigated for their chimeric status both in peripheral blood and plasma using standard PCR for microsatellite amplification. Plasma DNA size distribution was analyzed using capillary electrophoresis.

RESULTS

The mean cfDNA concentration in the transplanted patients was 469ng/ml (range: 50-10,700ng/ml). The size range of almost 80% of the analyzed fragments was between 80 and 200bp. In 41 out of the 110 patients included in the study a mixture of donor and recipient plasma cfDNA was detected. There was a statistically significant difference in the percentage of plasma mixed chimerism between the patients without transplant related complications and the patients with either GvHD (p<0.05) or relapse (p<0.01). In those patients who showed improvement of GvHD also displayed a decrease in the observable percentage of recipient cfDNA during GvHD treatment. In patients without improvement or even with worsening of acute GvHD, stable or increasing levels of recipient cfDNA were detected.

CONCLUSIONS

cfDNA in combination with peripheral blood and bone marrow cell chimerism analysis might improve its utility in the clinic in particular in those patients with clinical complications after alloHSCT.

Therapeutic options for leukemic transformation in patients with myeloproliferative neoplasms

Approximately 5-10% of patients with Philadelphia chromosome negative myeloproliferative neoplasms (MPN) comprising of essential thrombocythemia, polycythemia vera and primary myelofibrosis) experience transformation to acute myeloid leukemia (AML, ≥20% blasts). Treatment options for post-MPN AML patients are limited, as conventional approaches like standard chemotherapy, fail to offer long-term benefit. Median survival for secondary AML is ∼2.4 months. Post-MPN AML therefore represents an area of urgent clinical need. At present, allogeneic stem cell transplant (ASCT) following induction therapy is the best therapeutic option. Patients ineligible for ASCT are treated with hypomethylating agents. New agents under investigation include histone deacetylase inhibitors, JAKinhibitors and agents targeting the BRD4 protein. Combined treatment strategies involving these novel agents are being tested. In this review we present the current evidence regarding treatment options for post-MPN AML patients.

Early mixed hematopoietic chimerism detection by digital droplet PCR in patients undergoing gender-mismatched hematopoietic stem cell transplantation

Background:

Clinical decision making after allogeneic stem cell transplantation (HSCT) is partially based on hematopoietic chimerism analysis. Polymerase chain reaction amplification of polymorphic short tandem repeats (STR-PCR) is currently considered the gold standard for chimerism surveillance after transplantation. Nevertheless, this method has shown several limitations. Emerging technologies such as digital PCR (dPCR) has been applied to detect hematopoietic chimerism. Despite previous reports, the clinical usefulness of dPCR is unclear because the studies were performed in limited patient populations with short follow-ups.

Methods:

In order to compare hematopoietic chimerism detection time and rate, we analyzed 591 samples from 155 patients undergoing gender-mismatched HSCT using STR-PCR and dPCR. We also established the correlation between both methods in artificial DNA mixtures prepared in known proportions and in clinical samples.

Results:

Depending on the artificial DNA mixture analyzed the correlation coefficient between both methods was 0.9946 and 0.9732. The limit of detection for dPCR was 0.01%. Of 157 samples with donor and recipient DNA, mixed chimerism (MC) was detected solely by dPCR in 66 samples. Within the group of patients relapsing after HSCT (n=32) MC was detected earlier in 15 of these patients with dPCR in comparison with STR-PCR. The mean time from MC detection to relapse was 155 days (range: 13–385 days) and 65 days (range: 0–203 days) for dPCR and STR-PCR, respectively.

Conclusions:

dPCR is a sensitive and accurate method for the quantification of hematopoietic chimerism allowing earlier MC detection compared to STR-PCR.

Low-dose alemtuzumab for GvHD prevention followed by prophylactic donor lymphocyte infusions in high-risk leukemia

We analyzed the use of low-dose alemtuzumab in a cohort of 158 consecutive patients who underwent allogeneic PBSC transplantation. Patients with high-risk acute leukemia were prospectively screened for prophylactic donor lymphocyte infusion (pDLI). Lymphocytes were administered repeatedly at low and non-escalating doses (0.5-1 × 10⁶/kg). Low-dose alemtuzumab was effective in prevention of acute GvHD after sibling or well-matched unrelated transplantation, whereas a more intensified approach was needed after mismatched transplantation. The cumulative incidence of chronic moderate/severe chronic-GvHD (cGvHD) was 15.6%. In total, 63 high-risk leukemia patients were eligible for pDLI. Only 1 out of the 39 pDLI recipients relapsed as compared with 7 out of the 24 recipients, who did not receive pDLI due to logistical hurdles. In multivariate analysis, the use of adjuvant lymphocyte therapy was significantly associated with reduced incidence of relapse and improved disease-free survival. In summary, low-dose alemtuzumab confers to a low cGvHD incidence and the administration of pDLIs in this context is very likely to reduce relapse risk in high risk leukemia patients. This is translated in an estimated 5-year probability of GvHD-free and relapse-free survival of 43.3% for the 136 leukemia patients.

Therapeutic polo-like kinase 1 inhibition results in mitotic arrest and subsequent cell death of blasts in the bone marrow of AML patients and has similar effects in non-neoplastic cell lines

Polo-like kinase 1 (PLK1) is an important regulator of the cell cycle and is overexpressed in various solid and hematological malignancies. Small molecule inhibitors targeting PLK1, such as BI2536 or BI6727 (Volasertib) are a promising therapeutic approach in such malignancies. Here, we show a loss of specifically localized PLK1 in AML blasts in vivo, accompanied by mitotic arrest with transition into apoptosis, in bone marrow biopsies of AML patients after treatment with BI2536. We verify these results in live cell imaging experiments with the AML cell line HL-60, and demonstrate that non-neoplastic, immortalized lymphoblastoid cells are also sensitive to PLK1 inhibition. It is demonstrated that normal granulopoietic precursors have similar PLK1 expression levels as leukemic blasts. These results are in line with the adverse effects of PLK1 inhibition and underline the great potential of PLK1 inhibitors in the treatment of AML.

Allogeneic stem cell transplantation for refractory acute myeloid leukemia: a single center analysis of long-term outcome

For patients with refractory acute myeloid leukemia (AML), allogeneic stem cell transplantation (alloSCT) represents the only curative approach. We here analyzed the long-term outcome of 131 consecutive patients with active AML, which was either primary refractory or unresponsive to salvage chemotherapy, transplanted at our center between 1997 and 2013. After a median follow-up of 48 months for the surviving patients, disease-free survival (DFS) at 5 yr post alloSCT was 26% (94% CI: 17-35). Relapses, most of which occurred within the first 2 yr from transplant, were the predominant cause of treatment failure affecting 48% (95%CI: 40-58) of patients, whereas non-relapse mortality was 26% (95%CI: 20-36) at 5 yr and thereafter. A marrow blast count ≥20% before alloSCT was an independent prognosticator associated with an inferior DFS (HR: 1.58, P = 0.027), whereas the development of chronic graft-versus-host disease (cGvHD) predicted an improved DFS (HR 0.21, P < 0.001) and a decreased relapse incidence (HR: 0.18, P = 0.026), respectively. These results indicate that alloSCT represents a curative treatment option in a substantial proportion of patients with refractory AML. A pretransplant blast count <20% before alloSCT and the development of cGvHD are the most important predictors of long-term disease control.

[Current indications of allogeneic stem cell transplant in adults with acute myeloid leukemia]

Allogeneic stem cell transplantation (SCT) is an increasingly important therapeutic option for the treatment of adult patients with acute myeloid leukemia. Here we review the current indications of SCT in this disease. While patients with favorable cytogenetics should receive consolidation chemotherapy, patients with unfavorable karyotype are prime candidates for SCT or new approaches to SCT (which should be done in first complete remission). Patients with intermediate prognoses should also receive SCT in first complete remission. In the absence of a suitable matched related donor, most patients will be able to find an alternative donor to proceed to a potentially curative allogeneic transplantation. The use of reduced-intensity conditioning regimens before SCT has allowed patients in the sixth or seventh decades of life to be routinely transplanted. Despite major differences among transplant centers in the intensity and composition of the conditioning regimen and immunosuppression, choice of graft source, postgraft immune-modulation, and supportive care, there has been a dramatic improvement in terms of tolerance. Although it is presumed to be a curative strategy, major complications of SCT remain graft-versus-host disease, delayed immune recovery, multiple comorbidities, and relapse after transplant.

Comparison of reduced-intensity and myeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia and acute lymphoblastic leukemia: a meta-analysis

Currently, the indications to perform reduced-intensity conditioning allogeneic hematopoietic stem cell transplant (RIC-HCT) are based on data derived mainly from large registry and single-centre retrospective studies. Thus, at the present time, there is limited direct evidence supporting the current practice in selecting patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) for RIC versus myeloablative conditioning (MAC) transplants. To determine the relationship between dose intensity of conditioning regimen and survival outcomes after allografting in AML/ALL patients, we performed a meta-analysis of 23 clinical trials reported between 1990 and 2013 involving 15,258 adult patients that compare survival outcomes after RIC-HCT versus MAC-HCT. RIC-HCT resulted in comparable <2-year and 2-6 year overall survival (OS) rates post-transplantation even though the RIC-HCT recipients were older and had more active disease than MAC-HCT recipients. The 2-6 year progression-free survival (PFS), nonrelapse mortality, acute graft-versus-host disease (GvHD) and chronic GvHD rates were reduced after RIC-HCT, but relapse rate was increased. Similar outcomes were observed regardless of disease type and status at transplantation. Odds ratio for all outcomes remained comparable with or without performing separate analyses for the year of HCT and for retrospective versus prospective studies. Among RIC-HCT recipients, survival rates were superior if patients were in CR at transplantation. Significant inter-study heterogeneity for aGvHD data and publication bias for PFS data were observed. This meta-analysis showed no OS benefit of MAC-HCT over RIC-HCT across the entire cohort of patients suggesting that RIC-HCT could be an effective therapeutic option for AML/ALL patients who are ineligible for MAC-HCT and CR status is preferred before RIC-HCT.

Lowering the alemtuzumab dose in reduced intensity conditioning allogeneic hematopoietic cell transplantation is associated with a favorable early intense natural killer cell recovery

BACKGROUND AIMS

The anti-CD52 monoclonal antibody alemtuzumab is employed in allogeneic hematopoietic cell transplantation (alloHCT) for the prevention of graft-versus-host disease (GVHD). However, its optimal dosing in this setting has not been determined yet. We compared three different alemtuzumab dose levels in reduced intensity conditioning (RIC) alloHCT with respect to lymphocyte recovery and outcome.

METHODS

In 127 consecutive patients with predominantly advanced stage hematologic malignancies, a first alloHCT after RIC was performed, applying a fludarabine-based protocol (in 93% FBM: fludarabine, bis-chloroethyl-nitrosourea [BCNU], and melphalan). For GVHD prophylaxis, cyclosporine and alemtuzumab at three different dose levels (40 mg, 20 mg, 10 mg) were administered. Recovery of the peripheral blood (PB) lymphocyte sub-populations and clinical outcome were determined with regard to the alemtuzumab dose.

RESULTS

Natural killer (NK) cell concentrations in PB around day +30 correlated inversely with the alemtuzumab dose, whereas other PB lymphocyte subtypes remained essentially unaffected by dosing of alemtuzumab. Lower alemtuzumab doses were associated with a tendency toward improved overall survival mainly during the early post-transplantation months. With regard to the PB NK cell concentration around day +30, "early intense NK cell reconstituters" tended to show an overall survival benefit.

CONCLUSIONS

An alemtuzumab dose reduction to only 10-20 mg provides sufficient GVHD prophylaxis and supports improved NK cell regeneration early after alloHCT in PB ("NK cell saving effect"), which may have a positive effect on overall survival.

Prolonged Survival of a Refractory Acute Myeloid Leukemia Patient after a Third Hematopoietic Stem Cell Transplantation with Umbilical Cord Blood following a Second Relapse

Although hematopoietic stem cell transplantation (HSCT) has been considered to be the only way for potential cure of relapsed acute myeloid leukemia (AML), there has been no report on a third HSCT in patients with multiple relapsed AML. Here, we report a case of 53-year-old female who received a successful third allogeneic HSCT after relapse of AML following a second allogeneic HSCT. She was treated with a toxicity reduced conditioning regimen and received direct intrabone cord blood transplantation (CBT) using a single unit of 5/6 HLA-matched cord blood as a graft source. Graft-versus-host disease prophylaxis was performed with a single agent of tacrolimus to increase graft-versus-leukemia effect. She is in remission for 8 months since the direct intrabone CBT. This report highlights not only the importance of individually adjusted approach but also the need for further investigation on the role of HSCT as a treatment modality in patients with refractory or multiple relapsed AML.

Clinical results with the DNA hypomethylating agent 5-aza-2'-deoxycytidine (decitabine) in patients with myelodysplastic syndromes: an update

Patients with myelodysplastic syndromes (MDS), especially those with high-risk disease, other comorbidities, or of advanced age, still have a limited prognosis. In addition to cytotoxic chemotherapies, hypomethylating agents such as decitabine (5-aza-2'-deoxycytidine) and azacitidine (5-azacytidine), have been approved during the past decade and represent a very important option for the treatment of MDS today. Due to their lower toxicity compared to conventional chemotherapy, hypomethylating agents are often a safe and feasible alternative also for frail patients. Decitabine has been shown to be active in numerous studies including International Prognostic Scoring System (IPSS) intermediate-1 to high risk patients, in secondary acute myeloid leukemia (AML) arising from MDS, and in MDS with poor-risk cytogenetics. Furthermore, decitabine has been studied in the allograft setting and in combination treatment regimens, and may play a role in epigenetic "priming" before conventional chemotherapy. This review summarizes the results of clinical trials and experiences with decitabine not only in first-line and single-agent treatment regimens but also as second-line treatment after prior treatment failure, in the context of the allograft setting and as part of combination treatment regimens.

Indications and outcomes of reduced-toxicity hematopoietic stem cell transplantation in adult patients with hematological malignancies

Hematopoietic stem cell transplantation (HCT) utilizing non-myeloablative (NMA) and reduced-intensity conditioning (RIC) regimens (collectively referred to as reduced-toxicity HCT, RT-HCT) has become a viable therapeutic option for patients with hematological malignancies who are ineligible for standard myeloablative conditioning transplantation (MA-HCT). RT-HCT has been shown to induce stable engraftment with low toxicity, and to produce similar overall and progression-free survival (PFS) when compared to MA-HCT in acute myeloid leukemia and myelodysplastic syndrome. The best results for RT-HCT have been reported for patients with disease that is in remission, indolent and chemosensitive, and with a strong graft-versus-malignancy effect. Chronic graft-versus-host disease seems to correlate with a lower relapse rate and better PFS. RT-HCT is inferior when performed in poor risk or advanced disease, due to high relapse rates. A search for novel strategies that includes the most appropriate conditioning regimens and post-transplant immunomodulation protocols with more intensive anti-malignancy activity but limited toxicity is in progress. This review provides an update on the results of clinical studies of RT-HCT, and discusses possible indications and investigative strategies for improving the clinical outcomes of RT-HCT for the major hematological malignancies.

Reduced-intensity conditioning with fludarabine and thiotepa for second allogeneic transplantation of relapsed patients with AML

A second allograft was offered to 58 relapsed AML patients after conditioning with fludarabine 90-150 mg/m(2) and thiotepa 15 mg/kg, in most cases with active disease. Median age was 53 years (range 23-69), median time to relapse after the first allo-SCT was 326 (47-2189) days and median follow-up was 6.7 years. GVHD prophylaxis consisted mainly of CsA and alemtuzumab. Response rates at 1 month were CR in 50 and persistent disease in 3/53 evaluable patients. At 3 years, the relapse incidence (95% confidence interval) was 56 (45-71)%, the TRM 31 (21-46)%, the OS rate was 18 (9-29)% and the EFS rate was 13 (5-23)%. OS improved with younger patient age, longer relapse-free interval after the first allo-SCT and the development of chronic GVHD. Patients ≥ 65 years old who relapsed >12 months after the first allograft (n=20) had a 3-year OS rate of 41 (19-62)%. Conventional cytogenetics and FLT3 mutation status did not affect outcome. Our regimen is feasible and provides at least for a subgroup of patients with AML recurrence after allo-SCT a reasonable therapeutic option in an otherwise fatal situation. Further modifications and a better understanding of the underlying biology could help lower the risk of relapse.

Inflammatory neovascularization during graft-versus-host disease is regulated by αv integrin and miR-100

Acute graft-versus-host disease (GvHD) is a complex process involving endothelial damage and neovascularization. Better understanding of the pathophysiology of neovascularization during GvHD could help to target this process while leaving T-cell function intact. Under ischemic conditions, neovascularization is regulated by different micro RNAs (miRs), which potentially play a role in inflamed hypoxic GvHD target organs. We observed strong neovascularization in the murine inflamed intestinal tract (IT) during GvHD. Positron emission tomography imaging demonstrated abundant αvβ3 integrin expression within intestinal neovascularization areas. To interfere with neovascularization, we targeted αv integrin-expressing endothelial cells, which blocked their accumulation in the IT and reduced GvHD severity independent of immune reconstitution and graft-versus-tumor effects. Additionally, enhanced neovascularization and αv integrin expression correlated with GvHD severity in humans. Expression analysis of miRs in the inflamed IT of mice developing GvHD identified miR-100 as significantly downregulated. Inactivation of miR-100 enhanced GvHD indicating a protective role for miR-100 via blocking inflammatory neovascularization. Our data from the mouse model and patients indicate that inflammatory neovascularization is a central event during intestinal GvHD that can be inhibited by targeting αv integrin. We identify negative regulation of GvHD-related neovascularization by miR-100, which indicates common pathomechanistic features of GvHD and ischemia.

Pharmacological methods to reduce disease recurrence

Allogeneic stem cell transplantation is an increasingly important treatment option in patients with high-risk acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Although there has been substantial progress in reducing transplantation-related mortality (TRM), little progress has been made in reducing the risk of disease relapse, which continues to represent the major cause of treatment failure in patients allografted for AML and MDS. Experience with myeloablative conditioning regimens has demonstrated that, although intensification of the preparative regimen reduces relapse risk, any survival benefit is blunted by a concomitant increase in TRM. A similar inverse correlation between relapse risk and TRM is observed in patients allografted using a reduced-intensity conditioning regimen. However, the markedly lower toxicity of such regimens has permitted the design of novel conditioning strategies aimed at maximizing antitumor activity without excessive transplant toxicity. Coupled with recent advances in drug delivery and design, this has allowed the development of a spectrum of new conditioning regimens in patients with high-risk AML and MDS. At the same time, the optimization of a graft-versus-leukemia (GVL) effect by minimizing posttransplantation immunosuppression, with or without the infusion of donor lymphocytes, is essential if the risk of disease relapse is to be reduced. Recently, the delivery of adjunctive posttransplantation therapies has emerged as a promising method of augmenting antileukemic activity, either through a direct antitumor activity or consequent upon pharmacological manipulation of the alloreactive response. Taken together these advances present a realistic possibility of delivering improved outcome in patients allografted for high-risk AML or MDS.

Soluble HLA-G molecules and HLA-G 14-base pair polymorphism after allogeneic hematopoietic cell transplantation

HLA-G 14-base pair (bp) polymorphism and soluble human leukocyte antigen G were previously reported to be implicated in allogeneic hematopoietic cell transplantation (allo-HSCT) outcome. However, soluble HLA-G blood levels and the 14-bp insertion-deletion polymorphism were separately assessed in the context of allo-HSCT. The aim of the present study was to examine the influence of the 14-bp insertion/deletion polymorphism of the HLA-G gene together with the soluble HLA-G plasma levels on allo-HSCT complications. We investigated the possible impact of HLA-G 14-bp polymorphism together with the pretransplantation and posttransplantation concentration of soluble HLA-G in 59 patients undergoing allo-HSCT. No association was found between the HLA-G 14-bp polymorphism, the soluble HLA-G level and acute graft-versus-host disease (GvHD), disease recurrence, or death. In contrast with previous reports the present data suggest a weak or negligible involvement of both 14-bp polymorphism on HLA-G gene and sHLA-G concentration in posttransplantation complications such as acute or chronic GvHD, relapse, or death.