Unrelated donor granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cell transplantation after nonmyeloablative conditioning: the effect of postgrafting mycophenolate mofetil dosing

Dysregulated haemostasis in thrombo-inflammatory disease

Inflammatory disease is often associated with an increased incidence of venous thromboembolism in affected patients, although in most instances, the mechanistic basis for this increased thrombogenicity remains poorly understood. Acute infection, as exemplified by sepsis, malaria and most recently, COVID-19, drives 'immunothrombosis', where the immune defence response to capture and neutralise invading pathogens causes concurrent activation of deleterious prothrombotic cellular and biological responses. Moreover, dysregulated innate and adaptive immune responses in patients with chronic inflammatory conditions, such as inflammatory bowel disease, allergies, and neurodegenerative disorders, are now recognised to occur in parallel with activation of coagulation. In this review, we describe the detailed cellular and biochemical mechanisms that cause inflammation-driven haemostatic dysregulation, including aberrant contact pathway activation, increased tissue factor activity and release, innate immune cell activation and programmed cell death, and T cell-mediated changes in thrombus resolution. In addition, we consider how lifestyle changes increasingly associated with modern life, such as circadian rhythm disruption, chronic stress and old age, are increasingly implicated in unbalancing haemostasis. Finally, we describe the emergence of potential therapies with broad-ranging immunothrombotic functions, and how drug development in this area is challenged by our nascent understanding of the key molecular and cellular parameters that control the shared nodes of proinflammatory and procoagulant pathways. Despite the increasing recognition and understanding of the prothrombotic nature of inflammatory disease, significant challenges remain in effectively managing affected patients, and new therapeutic approaches to curtail the key pathogenic steps in immune response-driven thrombosis are urgently required.

Predictors and Outcomes of Dose Reduction of Methotrexate and Cyclosporin Graft-Versus-Host-Disease Prophylaxis Following Allogeneic Haematopoietic Cell Transplantation

BACKGROUND

Concern regarding dose-related toxicities of methotrexate (MTX) and cyclosporin (CYA) GVHD prophylaxis occasionally lead to dose alterations post allogeneic haematopoietic cell transplant (alloHCT).

AIM

To clarify causes of MTX and CYA dose alteration and assess impact on patient outcomes including GVHD, relapse, non-relapse mortality (NRM), and overall survival (OS).

METHOD

Analysis of retrospective data was performed in a single tertiary centre of patients who underwent alloHCT for any indication and who received GVHD prophylaxis with CYA and MTX between the years 2011 and 2015. Univariate analysis was conducted using the log-rank test for OS and using competing risk regression for NRM, relapse and GVHD. Fisher exact tests were used to determine if an association existed between each of the pre-transplant variables and MTX alteration. Multivariate models for OS and NRM were constructed using Cox proportional hazards modelling and competing risk regression respectively.

RESULTS

54/196 (28%) had MTX alterations and 61/187 (33%) had CYA alterations. Reasons for MTX alteration included mucositis, renal or liver impairment, fluid overload and sepsis. Causes of CYA alteration were numerous but most commonly due to acute kidney impairment. MTX alteration was associated with inferior OS (HR 2.4, P=<0.001) and higher NRM (OR 4.6, P<0.001) at 6 years(y) post-landmark. CYA alteration was associated with greater NRM (OR 2.7, P= 0.0137) at 6y. GVHD rates were unaffected by dose alteration.

CONCLUSIONS

Our findings suggest dose alteration in MTX and CYA GVHD prophylaxis is associated with adverse survival outcomes in alloHCT, without a significant impact on GVHD rates. This article is protected by copyright. All rights reserved.

Weight-based mycophenolate mofetil dosing predicts acute GVHD and relapse after allogeneic hematopoietic cell transplantation

OBJECTIVES

Higher MMF dose can reduce acute GVHD risk after allogeneic hematopoietic cell transplantation (HCT). We examined the effect of MMF dose, relative to patient actual body weight (mg/kg/day), on outcomes of 680 adults after HCT.

METHODS

MMF was combined with cyclosporine (n = 599) or sirolimus (n = 81). We divided MMF dose/kg/day in quartiles.

RESULTS

The median time to grade II-IV acute GVHD was 32 days. The incidence of grade II-IV acute GVHD at day 30 was 30% in 1st (<29), 20% in 2nd (29-34), 16% in 3rd (35-41), and 19% in 4th (≥42) quartile (P < .01). Corresponding relapse incidence at 1 year was 16%, 25%, 27%, and 31%, respectively (P = .01). In multivariate analysis, as compared to 1st quartile, higher dose of weight-based MMF reduced grade II-IV acute GVHD (HR = 0.64 for 2nd, HR = 0.48 for 3rd, and HR = 0.55 for 4th quartile), but increased the risk of relapse (HR = 1.63 for 2nd, HR = 1.75 for 3rd, and HR = 2.31 for 4th quartile).

CONCLUSIONS

Weight-based MMF dose had no significant impact on engraftment, chronic GVHD, or survival. These data suggest that higher weight-based MMF dose reduces the risk of acute GVHD at the expense of increased relapse and supports conducting prospective studies to optimize MMF dosing after HCT.

Short Tandem Repeats (STRs) as Biomarkers for the Quantitative Follow-Up of Chimerism after Stem Cell Transplantation: Methodological Considerations and Clinical Application

Chimerism refers to the relative proportion of donor and recipient DNA after hematopoietic stem cell transplantation (HSCT) and its quantitative follow-up is of great clinical utility in this setting. PCR of short tandem repeats (STR-PCR) constitutes the gold standard method for chimerism quantification, although more sensitive PCR techniques (such as qPCR) have recently arisen. We compared the sensitivity and the quantification capacity of both techniques in patient samples and artificial mixtures and demonstrated adequate performance of both methods, with higher sensitivity of qPCR and better quantification skills of STR-PCR. By qPCR, we then prospectively followed up 57 patients that were in complete chimerism (CC) by STR-PCR. Twenty-seven patients (59%) showed 0.1–1% recipient DNA in the bone marrow. Only 4 patients presented 0.1–1% recipient DNA in peripheral blood (PB), and one of them relapsed. Finally, by qPCR, we retrospectively studied the last sample that showed CC by STR-PCR prior to relapse in 8 relapsed patients. At a median of 59 days prior to relapse, six patients presented mixed chimerism by qPCR in PB. Since both approaches have complementary characteristics, we conclude that different techniques should be applied in different clinical settings and therefore propose a methodological algorithm for chimerism follow-up after HSCT.

Population pharmacokinetics and Bayesian estimators for intravenous mycophenolate mofetil in haematopoietic stem cell transplant patients

AIMS

Intravenous mycophenolate mofetil (IV MMF), a prodrug of mycophenolic acid (MPA), is used during nonmyeloablative and reduced-intensity conditioning haematopoetic stem cell transplantation (HCT) to improve engraftment and reduce graft-versus-host disease. The aims of this study were to develop population pharmacokinetic models and Bayesian estimators based on limited sampling strategies to allow for individual dose adjustment of intravenous mycophenolate mofetil administered by infusion in haematopoietic stem cell transplant patients.

METHODS

Sixty-three MPA concentration-time profiles (median [min-max] = 6 [4-7] samples) were collected from 34 HCT recipients transplanted for 14 (1-45) days and administered IV MMF every 8 hours, concomitantly with cyclosporine. The database was split into development (75%) and validation (25%) datasets. Pharmacokinetic models characterized by a single compartment with first-order elimination, combined with two gamma distributions to describe the transformation of MMF into mycophenolic acid, were developed using in parallel nonparametric (Pmetrics) and parametric (ITSIM) approaches. The performances of the models and the derived Bayesian estimators were evaluated in the validation set.

RESULTS

The best limited sampling strategy led to a bias (min, max), root mean square error between observed and modeled interdose areas under the curve in the validation dataset of -11.72% (-31.08%, 5.00%), 14.9% for ITSIM and -2.21% (-23.40%, 30.01%), 12.4% for Pmetrics with three samples collected at 0.33, 2 and 3 hours post dosing.

CONCLUSION

Population pharmacokinetic models and Bayesian estimators for IV MMF in HCT have been developed and are now available online (https://pharmaco.chu-limoges.fr) for individual dose adjustment based on the interdose area under the curve.

Prophylaxis and management of graft versus host disease after stem-cell transplantation for haematological malignancies: updated consensus recommendations of the European Society for Blood and Marrow Transplantation

Graft-versus-host disease (GVHD) is a major factor contributing to mortality and morbidity after allogeneic stem-cell transplantation. Because of the small number of results from well designed, large-scale, clinical studies there is considerable variability in the prevention and treatment of GVHD worldwide. In 2014, to standardise treatment approaches the European Society of Blood and Marrow Transplantation published recommendations on the management of GVHD in the setting of HLA-identical sibling or unrelated donor transplantation in adult patients with haematological malignancies. Here we update these recommendations including the results of study published after 2014. Evidence was searched in three steps: first, a widespread scan of published trials, meta-analyses, and systematic reviews; second, expert opinion was added for specific issues following several rounds of debate; and third, a refined search to target debated or rapidly updating issues. On the basis of this evidence and the 2014 recommendations, five members of the EBMT Transplant Complications Working Party created 38 statements on GVHD prophylaxis, drug management, and treatment of acute and chronic GVHD. Subsequently, they created the EBMT GVHD management recommendation expert panel by recruiting 20 experts with expertise in GVHD management. An email-based, two-round Delphi panel approach was used to manage the consensus. Modified National Comprehensive Cancer Network categories for evidence and consensus were applied to the approved statements. We reached 100% consensus for 29 recommendations and 95% consensus for nine recommendations. Key updates to these recommendations include a broader use of rabbit anti-T-cell globulin; lower steroid doses for the management of grade 2 acute GVHD with isolated skin or upper gastrointestinal tract manifestations; fluticasone, azithromycin, and montelukast should be used for bronchiolitis obliterans syndrome; and the addition of newer treatment options for resteroid-refractory acute and chronic GVHD. In addition, we discuss specific aspects of GVHD prophylaxis and management in the setting of haploidentical transplantation and in paediatric patients, but no formal recommendations on those procedures have been provided in this Review. The European Society of Blood and Marrow Transplantation proposes to use these recommendations as a basis for the routine management of GVHD during stem-cell transplantation.

Venous thromboembolism incidence in hematologic malignancies

Venous thromboembolism (VTE) remains a major cause of morbidity and mortality in patients with cancer. Although some very well validated scores delineate the risk of VTE by cancer subtype and other risk factors, hematologic malignancies are underrepresented in these models. This subgroup represents a unique entity that undergoes therapy that can be thrombogenic. The overall risk of VTE in patients with leukemia depends on the use of L-asparaginase treatment, older age, comorbidities and central venous catheters. Patients with acute promyelocytic leukemia are at particularly high risk of VTE but also have an increased risk of bleeding. Patients with aggressive lymphomas have a high incidence of VTE, roughly 10%. Patients with multiple myeloma at highest risk of VTE are those receiving immunomodulatory agents such as thalidomide or lenalidomide. Allogeneic stem cell transplantation carries a risk of thrombosis, particularly in patients developing graft versus host disease. This review summarizes the incidence of VTE in leukemia, lymphoma, myeloma and stem cell transplantation and provides practical guidance for preventing and managing VTE in patients with hematologic malignancies.

Inosine Monophosphate Dehydrogenase Pharmacogenetics in Hematopoietic Cell Transplantation Patients

We evaluated inosine monophosphate dehydrogenase (IMPDH) 1 and IMPDH2 pharmacogenetics in 247 recipient-donor pairs after nonmyeloablative hematopoietic cell transplant (HCT). Patients were conditioned with total body irradiation + fludarabine and received grafts from related or unrelated donors (10% HLA mismatch), with postgraft immunosuppression of mycophenolate mofetil (MMF) with a calcineurin inhibitor. Recipient and donor IMPDH genotypes (rs11706052, rs2278294, rs2278293) were not associated with day 28 T cell chimerism, acute graft-versus-host disease (GVHD), disease relapse, cytomegalovirus reactivation, nonrelapse mortality, or overall survival. Recipient IMPDH1 rs2278293 genotype was associated with a lower incidence of chronic GVHD (hazard ratio, .72; P = .008) in nonmyeloablative HCT recipients. Additional studies are needed to confirm these results with the goal of identifying predictive biomarkers to MMF that lower GVHD.

Pharmacokinetics of intravenous mycophenolate mofetil in allogeneic hematopoietic stem cell-transplanted Japanese patients

PURPOSE

Mycophenolate mofetil (MMF) is increasingly used among Japanese patients undergoing allogeneic hematopoietic stem cell transplantation (allo-SCT). Because pharmacokinetic data for MMF in the Asian population are limited, we conducted this investigation.

METHODS

Intravenous MMF (1000 mg/dose) was administered to 10 patients along with cyclosporine or tacrolimus for 10 days after allo-SCT; it was administered every 8 h in peripheral blood stem cell- and bone marrow-transplanted patients, and every 12 h in cord blood-transplanted patients. MMF was administered orally at the same dose from day 11. Plasma concentrations of mycophenolic acid (MPA) were measured by high-performance liquid chromatography.

RESULTS

The MPA AUC_0 - tau was 31.9 ± 3.4, 26.2 ± 2.4, and 21.0 ± 2.2 µg*h/mL, the mean C_trough was 0.25, 0.35, and 0.37 µg/mL, and the C_max was 10.8, 9.2, and 5.5 µg/mL on days 2, 9, and 16, respectively. The AUC_0 - tau and C_max were significantly higher after intravenous MMF dosing than after oral MMF dosing. All patients exhibited successful neutrophil engraftments in a median time of 18 days. Grade II acute graft-versus-host disease (GvHD) of the skin was observed in two patients, and one patient developed limited chronic GvHD. Individual cases of transient and curable grade III oral mucositis and diarrhea were observed; however, MMF was not discontinued. No other severe complications or infections were observed.

CONCLUSIONS

Intravenously administered MMF was safe and possibly effective in achieving higher MPA plasma concentrations for GvHD prophylaxis after allo-SCT in Japanese patients.

Venous thromboembolism is associated with graft-versus-host disease and increased non-relapse mortality after allogeneic hematopoietic stem cell transplantation

Although venous thromboembolism rates and risk factors are well described in patients with cancer, there are limited data on the incidence, risk factors and outcomes of thrombosis after allogeneic stem cell transplantation, a curative therapy for patients with hematologic malignancies. We aimed to determine the incidence and risks associated with venous thrombosis in allogeneic stem cell transplants. We studied 2276 recipients of first transplant between 2002–2013 at our institution with a median follow up of 50 months (range 4–146). Using pharmacy records and subsequent chart reviews, 190 patients who received systemic anticoagulation for venous thrombosis were identified. The 1-and 2-year cumulative incidence of all venous thrombotic events were 5.5% (95% confidence interval (CI) 4.6–6.5%) and 7.1% (95% CI 6.1–8.2%), respectively. There was no difference in age, sex, body mass index, diagnosis, disease risk index, conditioning intensity, donor type or graft source between transplant recipients with and without subsequent thrombosis. In multivariable models, both acute and chronic graft-versus-host disease were independently associated with thrombosis occurrence (Hazard ratio (HR)=2.05, 95% CI 1.52–2.76; HR=1.71, 95% CI 1.19–2.46, respectively). Upper extremity thrombosis differed from all other thromboses in terms of timing, risk factors and clinical impact, and was not associated with non-relapse mortality (HR=1.15; 95% CI 0.69–1.90), unlike all other thromboses which did increase non-relapse mortality (HR=1.71; 95% CI 1.17–2.49). In subgroup analysis evaluating conventional thrombosis predictors by comparing patients with and without thrombosis, a history of prior venous thrombosis was the only significant predictor. Venous thromboembolism has a high incidence after allogeneic stem cell transplant and is associated with graft-versus-host disease and non-relapse mortality.

The combination of cyclosporine and mycophenolate mofetil is less effective than cyclosporine and methotrexate in the prevention of acute graft-versus host disease after stem-cell transplantation from unrelated donors

Acute graft-versus-host disease (GVHD) is the major treatment-related complication after stem-cell transplantation (SCT) from unrelated-donors. Several GVHD prophylaxis regimens have been explored, but no regimen has shown superiority. We analyzed transplantation outcomes in 472 consecutive unrelated-donor SCT recipients, using cyclosporine/methotrexate (MTX, n = 314) or cyclosporine/mycophenolate-mofetil (MMF, n = 158) for GVHD prophylaxis. Neutrophil engraftment was faster after MMF, days 11 and 14, respectively (P = .001). Acute GVHD grade II-IV and III-IV occurred in 47% and 28% after MMF compared to 27% and 12% after MTX, respectively (P < .001). Nonrelapse mortality (NRM) was 44% and 24%, respectively (P < .001). Death associated with GVHD occurred in 25% and 8% (P < .0001), while other NRM causes occurred in 19% and 16%, respectively (P = .39). Relapse mortality was similar. Overall survival was better after MTX, 40% and 29%, respectively (P = .006). However, this difference had only borderline significance when adjusting for differences in patient characteristics (HR, 1.3, P = .08). To minimize potential selection bias we analyzed outcomes on the basis of an intention-to-treat like analysis. During the years 2008-2009, the leading GVHD prophylaxis regimen for unrelated-donor SCT included MMF (89% of transplants). During the other periods, MTX was used predominantly (82% of transplants). The two periods were otherwise well-matched. Acute GVHD occurred more often in 2008-2009. Death associated with GVHD occurred more often, while other NRM causes occurred less often resulting in similar NRM and overall survival. In conclusion, cyclosporine/MMF is associated with faster engraftment and possibly with less organ toxicity than cyclosporine/MTX. However, it is associated with increased rates of acute GVHD and GVHD-associated deaths.

Pharmacokinetics, Pharmacodynamics, and Pharmacogenomics of Immunosuppressants in Allogeneic Hematopoietic Cell Transplantation: Part II

Part I of this article included a pertinent review of allogeneic hematopoietic cell transplantation (alloHCT), the role of postgraft immunosuppression in alloHCT, and the pharmacokinetics, pharmacodynamics, and pharmacogenomics of the calcineurin inhibitors and methotrexate. In this article (Part II), we review the pharmacokinetics, pharmacodynamics, and pharmacogenomics of mycophenolic acid (MPA), sirolimus, and the antithymocyte globulins (ATG). We then discuss target concentration intervention (TCI) of these postgraft immunosuppressants in alloHCT patients, with a focus on current evidence for TCI and on how TCI may improve clinical management in these patients. Currently, TCI using trough concentrations is conducted for sirolimus in alloHCT patients. Several studies demonstrate that MPA plasma exposure is associated with clinical outcomes, with an increasing number of alloHCT patients needing TCI of MPA. Compared with MPA, there are fewer pharmacokinetic/dynamic studies of rabbit ATG and horse ATG in alloHCT patients. Future pharmacokinetic/dynamic research of postgraft immunosuppressants should include '-omics'-based tools: pharmacogenomics may be used to gain an improved understanding of the covariates influencing pharmacokinetics as well as proteomics and metabolomics as novel methods to elucidate pharmacodynamic responses.

Novel approaches for preventing acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

INTRODUCTION

Allogeneic hematopoietic stem cell transplantation (alloHSCT) offers potential curative treatment for a wide range of malignant and nonmalignant hematological disorders. However, its success may be limited by post-transplant acute graft-versus-host disease (aGVHD), a systemic syndrome in which donor's immune cells attack healthy tissues in the immunocompromised host. aGVHD is one of the main causes of morbidity and mortality after alloHSCT. Despite standard GVHD prophylaxis regimens, aGVHD still develops in approximately 40-60% of alloHSCT recipients.

AREAS COVERED

In this review, after a brief summary of current knowledge on the pathogenesis of aGVHD, the authors review the current combination of a calcineurin inhibitor with an antimetabolite with or without added anti-thymocyte globulin (ATG) and emerging strategies for GVHD prevention.

EXPERT OPINION

A new understanding of the involvement of cytokines, intracellular signaling pathways, epigenetics and immunoregulatory cells in GVHD pathogenesis will lead to new standards for aGVHD prophylaxis allowing better prevention of severe aGVHD without affecting graft-versus-tumor effects.

Venous thromboembolism following hematopoietic stem cell transplantation-a systematic review and meta-analysis

Venous thromboembolism (VTE) is a common complication of hematopoietic stem cell transplantation (HSCT). Graft-versus-host disease (GVHD) is another complication of HSCT that may modify the risk of VTE. Our objective was to explore the incidence of VTE (deep venous thrombosis and pulmonary embolism) following HSCT and to evaluate its association with GVHD. A comprehensive search of Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Scopus was conducted to search for both retrospective and prospective HSCT studies which had reported VTE. Random-effects meta-analysis was used to pool incidence rates. We included 17 studies reporting on allogeneic- and 10 on autologous-HSCT; enrolling 6693 patients; of which 5 were randomized. The overall incidence of VTE after HSCT was 5 % (4-7 %). Incidence in allogeneic-HSCT was 4 % (2-6 %) and in autologous-HSCT was 4 % (1-15 %). Eleven and nine studies reported data on acute and chronic GVHD, respectively. The incidence of VTE in chronic GVHD was 35 % (20-54 %), whereas in acute GVHD it was 47 % (32-62 %). Based on the results of this meta-analysis, VTE is a fairly common complication after HSCT, emphasizing the importance of assimilating guidelines for both treatment and prophylaxis in this patient population.

Association of fludarabine pharmacokinetic/dynamic biomarkers with donor chimerism in nonmyeloablative HCT recipients

PURPOSE

Fludarabine monophosphate (fludarabine) is an integral component of many reduced-intensity conditioning regimens for hematopoietic cell transplantation (HCT). Fludarabine's metabolite, 9-β-D-arabinofuranosyl-2-fluoroadenine (F-ara-A), undergoes cellular uptake and activation to form the active cytotoxic metabolite fludarabine triphosphate (F-ara-ATP), which inhibits cellular DNA synthesis in CD4(+) and CD8(+) cells. In this study, we evaluated whether fludarabine-based pharmacologic biomarkers were associated with clinical outcomes in HCT recipients.

METHODS

Participants with hematologic diseases were conditioned with fludarabine and low-dose total body irradiation (TBI) followed by allogeneic HCT and post-grafting immunosuppression. After fludarabine administration, we evaluated pharmacological biomarkers for fludarabine-F-ara-A area under the curve (AUC) and the ratio of circulating CD4(+) and CD8(+) cells (CD4(+)/CD8(+) ratio) after fludarabine administration-in 102 patients; F-ara-ATP accumulation rate in enriched CD4(+) and CD8(+) cells was evaluated in 36 and 34 patients, respectively.

RESULTS

Interpatient variability in the pharmacological biomarkers was high, ranging from 3.7-fold (F-ara-A AUC) to 39-fold (F-ara-ATP in CD8(+) cells). Circulating CD8(+) cells were more sensitive to fludarabine administration. A population pharmacokinetic-based sampling schedule successfully allowed for estimation of F-ara-A AUC in this outpatient population. There was a poor correlation between the F-ara-AUC and the F-ara-ATP accumulation rate in CD4(+) (R (2) = 0.01) and CD8(+) cells (R (2) = 0.00). No associations were seen between the four biomarkers and clinical outcomes (day +28 donor T cell chimerism, acute graft-versus-host disease (GVHD), neutrophil nadirs, cytomegalovirus reactivation, chronic GVHD, relapse, non-relapse mortality, or overall mortality).

CONCLUSIONS

Considerable interpatient variability exists in pharmacokinetic and fludarabine-based biomarkers, but these biomarkers are not associated with clinical outcomes in fludarabine/TBI-conditioned patients.

Immune Recovery after Allogeneic Hematopoietic Stem Cell Transplantation Following Flu-TBI versus TLI-ATG Conditioning

PURPOSE

A conditioning regimen for allogeneic hematopoietic cell transplantation (HCT) combining total lymphoid irradiation (TLI) plus anti-thymocyte globulin (ATG) has been developed to induce graft-versus-tumor effects without graft-versus-host disease (GVHD).

EXPERIMENTAL DESIGN

We compared immune recovery in 53 patients included in a phase II randomized study comparing nonmyeloablative HCT following either fludarabine plus 2 Gy total body irradiation (TBI arm, n = 28) or 8 Gy TLI plus ATG (TLI arm, n = 25).

RESULTS

In comparison with TBI patients, TLI patients had a similarly low 6-month incidence of grade II-IV acute GVHD, a lower incidence of moderate/severe chronic GVHD (P = 0.02), a higher incidence of CMV reactivation (P < 0.001), and a higher incidence of relapse (P = 0.01). While recovery of total CD8(+) T cells was similar in the two groups, with median CD8(+) T-cell counts reaching the normal values 40 to 60 days after allo-HCT, TLI patients had lower percentages of naïve CD8 T cells. Median CD4(+) T-cell counts did not reach the lower limit of normal values the first year after allo-HCT in the two groups. Furthermore, CD4(+) T-cell counts were significantly lower in TLI than in TBI patients the first 6 months after transplantation. Interestingly, while median absolute regulatory T-cell (Treg) counts were comparable in TBI and TLI patients, Treg/naïve CD4(+) T-cell ratios were significantly higher in TLI than in TBI patients the 2 first years after transplantation.

CONCLUSIONS

Immune recovery differs substantially between these two conditioning regimens, possibly explaining the different clinical outcomes observed (NCT00603954).

Intensified Mycophenolate Mofetil Dosing and Higher Mycophenolic Acid Trough Levels Reduce Severe Acute Graft-versus-Host Disease after Double-Unit Cord Blood Transplantation

Although mycophenolate mofetil (MMF) has replaced corticosteroids as immunosuppression in cord blood transplantation (CBT), optimal MMF dosing has yet to be established. We intensified MMF dosing from every 12 to every 8 hours to augment graft-versus-host disease (GVHD) prophylaxis in double-unit cord blood transplantation (dCBT) and evaluated outcomes according to the total daily MMF dose/kg in 174 dCBT recipients (median age, 39 years; range, 1 to 71) who underwent transplantation for hematologic malignancies. Recipients of an MMF dose ≤ the median (36 mg/kg/day) had an increased day 100 grade III and IV acute GVHD (aGVHD) incidence compared with patients who received >36 mg/kg/day (24% versus 8%, P = .008). Recipients of ≤ the median dose who had highly HLA allele (1 to 3 of 6) mismatched dominant units had the highest day 100 grade III and IV aGVHD incidence of 37% (P = .009). This finding was confirmed in multivariate analysis (P = .053). In 83 patients evaluated for mycophenolic acid (MPA) troughs, those with a mean week 1 and 2 trough < .5 μg/mL had an increased day 100 grade III and IV aGVHD of 26% versus 9% (P = .063), and those who received a low total daily MMF dose and had a low mean week 1 and 2 MPA trough had a 40% incidence (P = .008). Higher MMF dosing or MPA troughs had no impact on engraftment after myeloablation. This analysis supports intensified MMF dosing in milligram per kilogram per day and MPA trough level monitoring early after transplantation in dCBT recipients.

Non-myeloablative allogeneic hematopoietic cell transplantation following fludarabine plus 2 Gy TBI or ATG plus 8 Gy TLI: a phase II randomized study from the Belgian Hematological Society

BACKGROUND

Few studies thus far have compared head-to-head different non-myelooablative conditioning regimens for allogeneic hematopoietic cell transplantation (allo-HCT).

METHODS

Here, we report the results of a phase II multicenter randomized study comparing non-myeloablative allo-HCT from HLA-identical siblings (n = 54) or from 10/10 HLA-matched unrelated donors (n = 40) with either fludarabine plus 2 Gy total body irradiation (Flu-TBI arm; n = 49) or 8 Gy TLI + anti-thymocyte globulin (TLI-ATG arm; n = 45) conditioning.

RESULTS

The 180-day cumulative incidences of grade II-IV acute GVHD (primary endpoint) were 12.2% versus 8.9% in Flu-TBI and TLI-ATG patients, respectively (P = 0.5). Two-year cumulative incidences of moderate/severe chronic GVHD were 40.8% versus 17.8% in Flu-TBI and TLI-ATG patients, respectively (P = 0.017). Five Flu-TBI patients and 10 TLI-ATG patients received pre-emptive DLI for low donor chimerism levels, while 1 Flu-TBI patient and 5 TLI-ATG patients (including 2 patients given prior pre-emptive DLIs) received a second HCT for poor graft function, graft rejection, or disease progression. Four-year cumulative incidences of relapse/progression were 22% and 50% in Flu-TBI and TLI-ATG patients, respectively (P = 0.017). Four-year cumulative incidences of nonrelapse mortality were 24% and 13% in Flu-TBI and TLI-ATG patients, respectively (P = 0.5). Finally, 4-year overall (OS) and progression-free survivals (PFS) were 53% and 54%, respectively, in the Flu-TBI arm, versus 54% (P = 0.9) and 37% (P = 0.12), respectively, in the TLI-ATG arm.

CONCLUSIONS

In comparison to patients included in the Flu-TBI arm, patients included in the TLI-ATG arm had lower incidence of chronic GVHD, higher incidence of relapse and similar OS.

TRIAL REGISTRATION

The study was registered on ClinicalTrial.gov ( NCT00603954 ) and EUDRACT (2010-024297-19) .

Higher Dose of Mycophenolate Mofetil Reduces Acute Graft-versus-Host Disease in Reduced-Intensity Conditioning Double Umbilical Cord Blood Transplantation

Mycophenolate mofetil (MMF) is frequently used in hematopoietic cell transplantation (HCT) for graft-versus-host disease (GVHD) prophylaxis and to facilitate engraftment. We previously reported that a higher level of mycophenolic acid can be achieved with an MMF dose of 3 g/day than with 2 g/day. Here, we retrospectively compared clinical outcomes of reduced-intensity conditioning (RIC) double umbilical cord blood (dUCB) HCT recipients receiving cyclosporine A with MMF 2 g (n = 93) versus 3 g (n = 175) daily. Multiple regression analysis adjusted for antithymocyte globulin in the conditioning revealed that MMF 3 g/day led to a 49% relative risk (RR) reduction in grade II to IV acute GVHD rate (RR, .51; 95% confidence interval, .36 to .72; P < .01). However, the higher MMF dose was not protective for chronic GVHD. Additionally, MMF dose was not an independent predictor of neutrophil engraftment or treatment-related mortality at 6 months or 2-year post-transplantation disease relapse, disease-free survival, or overall survival. Higher MMF dose did not increase risk of infectious complications, and infection-related mortality was similar for both MMF doses. Our data indicate that MMF 3 g/day reduces the risk of acute GVHD without affecting other clinical outcomes and should be used for GVHD prophylaxis after RIC dUCB transplantation.

Bone marrow or peripheral blood for reduced-intensity conditioning unrelated donor transplantation

PURPOSE

There have been no randomized trials that have compared peripheral blood (PB) with bone marrow (BM) grafts in the setting of reduced-intensity conditioning (RIC) transplantations for hematologic malignancy. Because immune modulation plays a significant role in sustaining clinical remission after RIC, we hypothesize that higher graft-versus-host disease (GVHD) associated with PB transplantation may offer a survival advantage.

PATIENTS AND METHODS

The primary outcome evaluated was overall survival. Cox regression models were built to study outcomes after transplantation of PB (n = 887) relative to BM (n = 219) for patients with acute myeloid leukemia, myelodysplastic syndrome, or non-Hodgkin lymphoma, the three most common indications for unrelated RIC transplantation. Transplantations were performed in the United States between 2000 and 2008. Conditioning regimens consisted of an alkylating agent and fludarabine, and GVHD prophylaxis involved a calcineurin inhibitor (CNI) with either methotrexate (MTX) or mycophenolate mofetil (MMF).

RESULTS

After adjusting for age, performance score, donor-recipient HLA-match, disease, and disease status at transplantation (factors associated with overall survival), there were no significant differences in 5-year rates of survival after transplantation of PB compared with BM: 34% versus 38% with CNI-MTX and 27% versus 20% with CNI-MMF GVHD prophylaxis.

CONCLUSION

Survival after transplantation of PB and BM are comparable in the setting of nonirradiation RIC regimens for hematologic malignancy. The effect of GVHD prophylaxis on survival merits further evaluation.

Recipient pretransplant inosine monophosphate dehydrogenase activity in nonmyeloablative hematopoietic cell transplantation

Mycophenolic acid, the active metabolite of mycophenolate mofetil (MMF), inhibits inosine monophosphate dehydrogenase (IMPDH) activity. IMPDH is the rate-limiting enzyme involved in de novo synthesis of guanosine nucleotides and catalyzes the oxidation of inosine 5'-monophosphate to xanthosine 5'-monophosphate (XMP). We developed a highly sensitive liquid chromatography-mass spectrometry method to quantitate XMP concentrations in peripheral blood mononuclear cells (PMNCs) isolated from the recipient pretransplant and used this method to determine IMPDH activity in 86 nonmyeloablative allogeneic hematopoietic cell transplantation (HCT) patients. The incubation procedure and analytical method yielded acceptable within-sample and within-individual variability. Considerable between-individual variability was observed (12.2-fold). Low recipient pretransplant IMPDH activity was associated with increased day +28 donor T cell chimerism, more acute graft-versus-host disease (GVHD), lower neutrophil nadirs, and more cytomegalovirus reactivation but not with chronic GVHD, relapse, nonrelapse mortality, or overall mortality. We conclude that quantitation of the recipient's pretransplant IMPDH activity in PMNC lysate could provide a useful biomarker to evaluate a recipient's sensitivity to MMF. Further trials should be conducted to confirm our findings and to optimize postgrafting immunosuppression in nonmyeloablative HCT recipients.

A randomized phase II trial of tacrolimus, mycophenolate mofetil and sirolimus after non-myeloablative unrelated donor transplantation

The study is a randomized phase II trial investigating graft-versus-host disease prophylaxis after non-myeloablative (90 mg/m(2) fludarabine and 2 Gy total body irradiation) human leukocyte antigen matched unrelated donor transplantation. Patients were randomized as follows: arm 1 - tacrolimus 180 days and mycophenolate mofetil 95 days (n=69); arm 2 - tacrolimus 150 days and mycophenolate mofetil 180 days (n=71); arm 3 - tacrolimus 150 days, mycophenolate mofetil 180 days and sirolimus 80 days (n=68). All patients had sustained engraftment. Grade II-IV acute graft-versus-host disease rates in the 3 arms were 64%, 48% and 47% at Day 150, respectively (arm 3 vs. arm 1 (hazard ratio 0.62; P=0.04). Owing to the decreased incidence of acute graft-versus-host disease, systemic steroid use was lower at Day 150 in arm 3 (32% vs. 55% in arm 1 and 49% in arm 2; overall P=0.009 by hazard ratio analysis). The Day 150 incidence of cytomegalovirus reactivation was lower in arm 3 (arm 1, 54%; arm 2, 47%; arm 3, 22%; overall P=0.002 by hazard ratio analysis). Non-relapse mortality was comparable in the three arms at two years (arm 1, 26%; arm 2, 23%; arm 3, 18%). Toxicity rates and other outcome measures were similar between the three arms. The addition of sirolimus to tacrolimus and mycophenolate mofetil is safe and associated with lower incidence of acute graft-versus-host disease and cytomegalovirus reactivation. (clinicaltrials.gov identifier: 00105001).

Nonrelapse mortality and mycophenolic acid exposure in nonmyeloablative hematopoietic cell transplantation

We evaluated the pharmacodynamic relationships between mycophenolic acid (MPA), the active metabolite of mycophenolate mofetil (MMF), and outcomes in 308 patients after nonmyeloablative hematopoietic cell transplantation. Patients were conditioned with total body irradiation ± fludarabine, received grafts from HLA-matched related (n = 132) or unrelated (n = 176) donors, and received postgrafting immunosuppression with MMF and a calcineurin inhibitor. Total and unbound MPA pharmacokinetics were determined to day 25; maximum a posteriori Bayesian estimators were used to estimate total MPA concentration at steady state (Css). Rejection occurred in 9 patients, 8 of whom had a total MPA Css less than 3 μg/mL. In patients receiving a related donor graft, MPA Css was not associated with clinical outcomes. In patients receiving an unrelated donor graft, low total MPA Css was associated with increased grades III to IV acute graft-versus-host disease and increased nonrelapse mortality but not with day 28 T cell chimerism, disease relapse, cytomegalovirus reactivation, or overall survival. We conclude that higher initial oral MMF doses and subsequent targeting of total MPA Css to greater than 2.96 μg/mL could lower grades III to IV acute graft-versus-host disease and nonrelapse mortality in patients receiving an unrelated donor graft.

Population pharmacokinetics and dose optimization of mycophenolic acid in HCT recipients receiving oral mycophenolate mofetil

We sought to create a population pharmacokinetic model for total mycophenolic acid (MPA), to study the effects of different covariates on MPA pharmacokinetics, to create a limited sampling schedule (LSS) to characterize MPA exposure (i.e., area under the curve or AUC) with maximum a posteriori Bayesian estimation, and to simulate an optimized dosing scheme for allogeneic hematopoietic cell transplantation (HCT) recipients. Four thousand four hundred ninety-six MPA concentration-time points from 408 HCT recipients were analyzed retrospectively using a nonlinear mixed effects modeling approach. MPA pharmacokinetics was characterized with a two-compartment model with first-order elimination and a time-lagged first-order absorption process. Concomitant cyclosporine and serum albumin were significant covariates. The median MPA clearance (CL) and volume of the central compartment were 24.2 L/hour and 36.4 L, respectively, for a 70 kg patient receiving tacrolimus with a serum albumin of 3.4 g/dL. Dosing simulations indicated that higher oral MMF doses are needed with concomitant cyclosporine, which increases MPA CL by 33.8%. The optimal LSS was immediately before and at 0.25 hours, 1.25 hours, 2 hours, and 4 hours after oral mycophenolate mofetil administration. MPA AUC in an individual HCT recipient can be accurately estimated using a five-sample LSS and maximum a posteriori Bayesian estimation.

Double umbilical cord blood transplantation in patients with hematologic malignancies using a reduced-intensity preparative regimen without antithymocyte globulin

Reduced-intensity conditioning (RIC) regimens in cord blood transplant (CBT) are increasingly utilized for older patients and those with comorbidities. However, the optimal conditioning regimen has not yet been established and remains a significant challenge of this therapeutic approach. Antithymocyte globulin (ATG) has been incorporated into conditioning regimens in order to decrease the risk of graft failure; however, use of ATG is often associated with infusion reactions and risk of post-transplant complications. We report the results of a non-ATG-containing RIC regimen, where patients received 2 Gy TBI unless they were considered to be at higher risk of graft failure, in which case they received 3 Gy of TBI. Thirty patients underwent CBT using this protocol for high-risk hematological malignancies. There was only one case of secondary and no cases of primary graft failure. At 1 year, estimates of non-relapse mortality, OS and PFS were 29%, 53% and 45%, respectively. The cumulative incidences of grade III-IV acute and chronic GVHD were 14% and 18%, respectively. In summary, the results of this study demonstrate that this non-ATG-containing conditioning regimen provides a low incidence of graft failure without increasing regimen-related toxicity.

A limited sampling schedule to estimate mycophenolic Acid area under the concentration-time curve in hematopoietic cell transplantation recipients

Mycophenolate mofetil (MMF) is a key component of postgrafting immunosuppression in hematopoietic cell transplant (HCT) recipients. The plasma area under the curve (AUC) of its active metabolite, mycophenolic acid (MPA), is associated with MMF efficacy and toxicity. This study developed a population pharmacokinetic model of MPA in HCT recipients and created limited sampling schedules (LSSs) to enable individualized pharmacotherapy. A retrospective evaluation of MPA concentration-time data following a 2-hour MMF intravenous (IV) infusion was conducted in 77 HCT recipients. The final model consisted of 1 and 2 compartments for MMF and MPA pharmacokinetics, respectively. The mean estimated values (coefficient of variation, %) for total systemic clearance, distributional clearance, and central and peripheral compartment volumes of MPA were 36.9 L/h (34.5%), 15.3 L/h (80.4%), 11.9 L (71.7%), and 182 L (127%), respectively. No covariates significantly explained variability among individuals. Optimal LSSs were derived using a simulation approach based on the scaled mean squared error. A 5-sample schedule of 2, 2.5, 3, 5, and 6 hours from the start of the infusion precisely estimated MPA AUC(0-12 h) for Q12-hour IV MMF. A comparable schedule (2, 2.5, 3, 4, and 6 hours) similarly estimated MPA AUC(0-8) (h) for Q8-hour dosing.

Mesenchymal stromal cells: a new tool against graft-versus-host disease?

Mesenchymal stromal cells (MSCs) represent a heterogeneous subset of multipotent cells that can be isolated from several tissues including bone marrow and fat. MSCs exhibit immunomodulatory and anti-inflammatory properties that prompted their clinical use as prevention and/or treatment for severe graft-versus-host disease (GVHD). Although a number of phase I-II studies have suggested that MSC infusion was safe and might be effective for preventing or treating acute GVHD, definitive proof of their efficacy remains lacking thus far. Multicenter randomized studies are ongoing to more precisely assess the impact of MSC infusion on GVHD prevention/treatment, whereas further research is performed in vitro and in animal models with the aims of determining the best way to expand MSCs ex vivo as well as the most efficient dose and schedule of MSCs administration. After introducing GVHD, MSC biology, and results of MSC infusion in animal models of allogeneic hematopoietic cell transplantation, this article reviews the results of the first clinical trials investigating the use of MSC infusion as prevention or treatment of GVHD.

Non-myeloablative conditioning with allogeneic hematopoietic cell transplantation for the treatment of high-risk acute lymphoblastic leukemia

BACKGROUND

Allogeneic hematopoietic cell transplantation is a potentially curative treatment for patients with acute lymphoblastic leukemia. However, the majority of older adults with acute lymphoblastic leukemia are not candidates for myeloablative conditioning regimens. A non-myeloablative preparative regimen is a reasonable treatment option for this group. We sought to determine the outcome of non-myeloablative conditioning and allogeneic transplantation in patients with high-risk acute lymphoblastic leukemia.

DESIGN AND METHODS

Fifty-one patients (median age 56 years) underwent allogeneic hematopoietic cell transplantation from sibling or unrelated donors after fludarabine and 2 Gray total body irradiation. Twenty-five patients had Philadelphia chromosome-positive acute lymphoblastic leukemia. Eighteen of these patients received post-grafting imatinib.

RESULTS

With a median follow-up of 43 months, the 3-year overall survival was 34%. The 3-year relapse/progression and non-relapse mortality rates were 40% and 28%, respectively. The cumulative incidences of grades II and III-IV acute graft-versus-host disease were 53% and 6%, respectively. The cumulative incidence of chronic graft-versus-host disease was 44%. Hematopoietic cell transplantation in first complete remission and post-grafting imatinib were associated with improved survival (P=0.005 and P=0.03, respectively). Three-year overall survival rates for patients with Philadelphia-negative acute lymphoblastic leukemia in first remission and beyond first remission were 52% and 8%, respectively. For patients with Philadelphia chromosome-positive acute lymphoblastic leukemia in first remission who received post-grafting imatinib, the 3-year overall survival rate was 62%; for the subgroup without evidence of minimal residual disease at transplantation, the overall survival was 73%.

CONCLUSIONS

For patients with high-risk acute lymphoblastic leukemia in first complete remission, non-myeloablative conditioning and allogeneic hematopoietic cell transplantation, with post-grafting imatinib for Philadelphia chromosome-positive disease, can result in favorable long-term survival.

Histology and time to progression predict survival for lymphoma recurring after reduced-intensity conditioning and allogeneic hematopoietic cell transplantation

Reduced-intensity conditioning (RIC) before allogeneic hematopoietic cell transplantation (HCT) is increasingly used as a potentially curative option for patients with advanced lymphoma; however, relapse remains a major challenge. Unfortunately, little data are available on outcomes, predictors of survival, and results of specific management strategies in these patients. In the present study, a total of 101 consecutive relapses occurred and were evaluated in 280 patients with lymphoma who underwent RIC HCT. Diseases included aggressive non-Hodgkin lymphoma (NHL) (n = 42), indolent NHL (n = 33), and Hodgkin lymphoma (HL) (n = 26). Median time to relapse was 90 days (range, 3-1275 days), and graft-versus-host disease at relapse was present in 56 patients (55%). Interventions after relapse included no therapy (n = 14), withdrawal of immunosuppression alone (n = 11), chemoradiotherapy (n = 60), and donor lymphocyte infusion/second HCT (n = 16). Overall survival (OS) was 33% (95% confidence interval [CI], 23%-44%) at 3 years after relapse and 23% (95% CI, 13%-34%) at 5 years after relapse. Both aggressive NHL (vs indolent disease; hazard ratio, 2.29; P = .008) and relapse within 1 month post-HCT (vs >6 months; hazard ratio, 3.17; P = .004) were associated with increased mortality. Estimated 3-year OS was 16% (95% CI, 5%-32%) after relapse for aggressive NHL, 40% (95% CI, 19%-61%) after relapse for indolent NHL, and 47% (95% CI, 29%-64%) after relapse for HL. The 1-year survival was 24% for patients relapsing within 1 month post-HCT, compared with 52% for those relapsing at 1-3 months, 74% for those relapsing at 3-6 months, and 77% for those relapsing at more than 6 months. We conclude that despite relapse of lymphoma after RIC HCT, some patients may experience prolonged survival, with better postrelapse outcomes occurring in patients with indolent NHL, HL, or late relapse.

A limited sampling strategy for estimation of the area under the curve (0 to 8 hours) of mycophenolic acid administered three times daily to liver transplant recipients

OBJECTIVES

Gastrointestinal side-effects caused by mycophenolic acid (MPA) are frequent in liver transplant recipients, and in these cases a switch from two to three daily doses is usually recommended. However, a limited sampling strategy for the estimation of MPA area under the curve from 0 to 8 hours (AUC(0-8h)) has not been made.

DESIGN AND METHODS

In 22 liver transplant patients who were administered MPA three times daily, the trapezoidal extrapolated MPA AUC(0-8h) values using a sampling time from 0 to 2 hours were calculated.

RESULTS

A tentative therapeutic range for MPA AUC(0-8h) of about 20-40 μg.h/mL is proposed, and in the 13 patients with supratherapeutic values the total leukocyte blood count was significantly lower than in the 9 patients with AUC(0-8h) ≤ 40 μg.h/mL (P < 0.001). Significant negative correlations were found between the total leukocyte blood count and the MPA trough levels (r = -0.458; P < 0.05), AUC(0-8h) (r = -0.479; P < 0.05), and AUC(0-2h) (r = -0.437; P < 0.05). A significant correlation was found between the trapezoidal extrapolated AUC(0-8h) and trapezoidal AUC(0-2h) results (r = 0.850; P < 0.001).

CONCLUSIONS

The trapezoidal extrapolated AUC(0-8h), and possibly trapezoidal AUC(0-2h), may be useful for routine therapeutic MPA monitoring in liver transplant recipients in which the dosing frequency is increased from twice to three times a day.

Thymic recovery after allogeneic hematopoietic cell transplantation with non-myeloablative conditioning is limited to patients younger than 60 years of age

BACKGROUND

Long-term immune recovery in older patients given hematopoietic cell transplantation after non-myeloablative conditioning remains poorly understood. This prompted us to investigate long-term lymphocyte reconstitution and thymic function in 80 patients given allogeneic peripheral blood stem cells after non-myeloablative conditioning.

DESIGN AND METHODS

Median age at transplant was 57 years (range 10-71). Conditioning regimen consisted of 2 Gy total body irradiation (TBI) with (n=46) or without (n=20) added fludarabine, 4 Gy TBI with fludarabine (n=6), or cyclophosphamide plus fludarabine (n=8). Stem cell sources were unmanipulated (n=56), CD8-depleted (n=19), or CD34-selected (n=5) peripheral blood stem cells. Immune recovery was assessed by signal-joint T-cell receptor excision circle quantification and flow cytometry.

RESULTS

Signal-joint T-cell receptor excision circle levels increased from day 100 to one and two years after transplantation in patients under 50 years of age (n=23; P=0.02 and P=0.04, respectively), and in those aged 51-60 years (n=35; P=0.17 and P=0.06, respectively), but not in patients aged over 60 (n=22; P=0.3 and P=0.3, respectively). Similarly, CD4(+)CD45RA(+) (naïve) T-cell counts increased from day 100 to one and two years after transplantation in patients aged 50 years and under 50 (P=0.002 and P=0.02, respectively), and in those aged 51-60 (P=0.4 and P=0.001, respectively), but less so in patients aged over 60 (P=0.3 and P=0.06, respectively). In multivariate analyses, older patient age (P<0.001), extensive chronic GVHD (P<0.001), and prior (resolved) extensive chronic graft-versus-host disease (P=0.008) were associated with low signal-joint T-cell receptor excision circle levels one year or more after HCT.

CONCLUSIONS

In summary, our data suggest that thymic neo-generation of T cells occurred from day 100 onwards in patients under 60 while signal-joint T-cell receptor excision circle levels remained low for patients aged over 60. Further, chronic graft-versus-host disease had a dramatic impact on thymic function, as observed previously in patients given grafts after myeloablative conditioning.

High-risk myelodysplastic syndromes: chemotherapy, transplantation, and beyond

Allogeneic hematopoietic cell transplantation (HCT) has curative potential for patients with myelodysplastic syndromes (MDS), though with considerable nonrelapse mortality and morbidity. The International Prognostic Scoring System, despite its confines, remains a widely used tool guiding treatment decisions in MDS. The two hypomethylating agents, 5-azacytidine (azacitidine) and 5-aza-2-deoxycytidine (decitabine), are both effective in high-risk MDS, but about 50% of high-risk MDS patients fail to achieve a meaningful response, and these agents offer only a modest survival benefit, with a median response duration of 13 months. The more recent proposed risk models of MDS, as well as modern transplant strategies and expanded alternative donor sources, have helped to increase the number of patients offered curative treatment. As both drug therapy and HCT modalities evolve, treatment decisions are certain to become more complex. Current therapeutic options should view the hypomethylating agents as a way to optimize disease response before (and possibly after) HCT.

Cotransplantation of mesenchymal stem cells might prevent death from graft-versus-host disease (GVHD) without abrogating graft-versus-tumor effects after HLA-mismatched allogeneic transplantation following nonmyeloablative conditioning

Recent studies have suggested that coinfusion of mesenchymal stem cells (MSCs) the day of hematopoietic cell transplantation (HCT) might promote engraftment and prevent graft-versus-host disease (GVHD) after myeloablative allogeneic HCT. This prompted us to investigate in a pilot study whether MSC infusion before HCT could allow nonmyeloablative (NMA) HCT (a transplant strategy based nearly exclusively on graft-versus-tumor effects for tumor eradication) from HLA-mismatched donors to be performed safely. Twenty patients with hematologic malignancies were given MSCs from third party unrelated donors 30-120 minutes before peripheral blood stem cells (PBSCs) from HLA-mismatched unrelated donors, after conditioning with 2 Gy total body irradiation (TBI) and fludarabine. The primary endpoint was safety, defined as a 100-day incidence of nonrelapse mortality (NRM) <35%. One patient had primary graft rejection, whereas the remaining 19 patients had sustained engraftment. The 100-day cumulative incidence of grade II-IV acute GVHD (aGVHD) was 35%, whereas 65% of the patients experienced moderate/severe chronic GVHD (cGVHD). One-year NRM (10%), relapse (30%), overall survival (OS) (80%) and progression-free survival (PFS) (60%), and 1-year incidence of death from GVHD or infection with GVHD (10%) were encouraging. These figures compare favorably with those observed in a historic group of 16 patients given HLA-mismatched PBSCs (but no MSCs) after NMA conditioning, which had a 1-year incidence of NRM of 37% (P = .02), a 1-year incidence of relapse of 25% (NS), a 1-year OS and PFS of 44% (P = .02), and 38% (P = .1), respectively, and a 1-year rate of death from GVHD or infection with GVHD of 31% (P = .04). In conclusion, our data suggest that HLA-mismatched NMA HCT with MSC coinfusion appeared to be safe.

Elevations of tumor necrosis factor receptor 1 at day 7 and acute graft-versus-host disease after allogeneic hematopoietic cell transplantation with nonmyeloablative conditioning

Acute GVHD has remained a significant cause of nonrelapse mortality after allogeneic hematopoietic cell transplantation (HCT) with nonmyeloablative conditioning. The role of TNF-alpha in the biology of acute GVHD after nonmyeloablative conditioning has not been studied thus far. Here, we measured TNF receptor 1 (TNFR1) as a surrogate marker for TNF-alpha in 106 patients before the start of the conditioning regimen (baseline) and 7 days after allogeneic HCT with nonmyeloablative conditioning. The nonmyeloablative regimen consisted of 2 Gy TBI alone (n=15), 2 Gy TBI plus fludarabine 90 mg/m2 (n=73), or 4 Gy TBI plus fludarabine 90 mg/m2 (n=18). TNFR1 levels increased significantly from baseline to day 7 after nonmyeloablative HCT (P<0.0001). Patients conditioned with 4 Gy TBI had higher TNFR1 day 7/baseline ratio than those conditioned with 2 Gy TBI (median 1.65 versus 1.25; P=0.01). In a multivariate Cox model, high TNFR1 day7/baseline ratio was associated with grades II-IV (HR=2.2, P=0.01) and grades III-IV (HR=2.9, P=0.007) acute GVHD, but had no impact on overall survival (P=0.8). In summary, our data suggest that nonmyeloablative conditioning induces the generation of TNF-alpha, and that the magnitude of TNF-alpha generation depends on the conditioning intensity (2 Gy versus 4 Gy TBI). Further, assessment of TNFR1 levels before and on day 7 after nonmyeloablative HCT provided useful information on subsequent risk of experiencing acute GVHD.

Pharmacokinetic modelling and development of Bayesian estimators for therapeutic drug monitoring of mycophenolate mofetil in reduced-intensity haematopoietic stem cell transplantation

BACKGROUND

Mycophenolate mofetil, a prodrug of mycophenolic acid (MPA), is used during non-myeloablative and reduced-intensity conditioning haematopoetic stem cell transplantation (HCT) to improve engraftment and reduce graft-versus-host disease (GVHD). However, information about MPA pharmacokinetics is sparse in this context and its use is still empirical.

OBJECTIVES

To perform a pilot pharmacokinetic study and to develop maximum a posteriori Bayesian estimators (MAP-BEs) for the estimation of MPA exposure in HCT.

PATIENTS AND METHODS

Fourteen patients administered oral mycophenolate mofetil 15 g/kg three times daily were included. Two consecutive 8-hour pharmacokinetic profiles were performed on the same day, 3 days before and 4 days after the HCT. One 8-hour pharmacokinetic profile was performed on day 27 after transplantation. For these 8-hour pharmacokinetic profiles, blood samples were collected predose and 20, 40, 60, 90 minutes and 2, 4, 6 and 8 hours post-dose. Using the iterative two-stage (ITS) method, two different one-compartment open pharmacokinetic models with first-order elimination were developed to describe the data: one with two gamma laws and one with three gamma laws to describe the absorption phase. For each pharmacokinetic profile, the Akaike information criterion (AIC) was calculated to evaluate model fitting. On the basis of the population pharmacokinetic parameters, MAP-BEs were developed for the estimation of MPA pharmacokinetics and area under the plasma concentration-time curve (AUC) from 0 to 8 hours at the different studied periods using a limited-sampling strategy. These MAP-BEs were then validated using a data-splitting method.

RESULTS

The ITS approach allowed the development of MAP-BEs based either on 'double-gamma' or 'triple-gamma' models, the combination of which allowed correct estimation of MPA pharmacokinetics and AUC on the basis of a 20 minute-90 minute-240 minute sampling schedule. The mean bias of the Bayesian versus reference (trapezoidal) AUCs was <5% with <16% of the patients with absolute bias on AUC >20%. AIC was systematically calculated for the choice of the most appropriate model fitting the data.

CONCLUSION

Pharmacokinetic models and MAP-BEs for mycophenolate mofetil when administered to HCT patients have been developed. In the studied population, they allowed the estimation of MPA exposure based on three blood samples, which could be helpful in conducting clinical trials for the optimization of MPA in reduced-intensity HCT. However, prior studies will be needed to validate them in larger populations.

Low-dose total body irradiation and fludarabine conditioning for HLA class I-mismatched donor stem cell transplantation and immunologic recovery in patients with hematologic malignancies: a multicenter trial

HLA-mismatched grafts are a viable alternative source for patients without HLA-matched donors receiving ablative hematopoietic cell transplantation (HCT), although their use in reduced intensity conditioning (RIC) or nonmyeloablative (NMA) conditioning HCT has been not well established. Here, we extended HCT to recipients of HLA class I-mismatched grafts to investigate whether NMA conditioning can establish stable donor engraftment. Fifty-nine patients were conditioned with fludarabine (Flu) 90 mg/m(2) and 2 Gy total body irradiation (TBI), followed by immunosuppression with cyclosporine (CsA) 5.0 mg/kg twice a day and mycophenolate mofetil (MMF) 15 mg/kg 3 times a day for transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood stem cells (PBSCs) from related (n = 5) or unrelated donors (n = 54) with 1 antigen +/- 1 allele HLA class I mismatch or 2 HLA class I allele mismatches. Sustained donor engraftment was observed in 95% of the evaluable patients. The incidence of grade II-IV acute and extensive chronic graft-versus-host disease (aGVHD, cGVHD) was 69% and 41%, respectively. The cumulative probability of nonrelapse mortality (NRM) was 47% at 2 years. Two-year overall and progression-free survival (OS, PFS) was 29% and 28%, respectively. NMA conditioning with Flu and low-dose TBI, followed by HCT using HLA class I-mismatched donors leads to successful engraftment and long-term survival; however, the high incidence of aGVHD and NRM needs to be addressed by alternate GVHD prophylaxis regimens.

Pharmacokinetics of mycophenolic acid administered 3 times daily after hematopoietic stem cell transplantation with reduced-intensity regimen

Mycophenolate mofetil (MMF) is an immunosuppressive drug used as a prophylactic agent to prevent acute graft-versus-host disease (aGVHD) after hematopoietic stem cell transplantation (HSCT). After reduced-intensity conditioning (RIC) regimen, administration of MMF orally 3 times a day (tid) seems to be more beneficial than twice a day (bid). However, information regarding the pharmacokinetic (PK) parameters of mycophenolic acid (MPA), the active metabolite of MMF, administered in this regimen are very limited. We performed a prospective study in 15 patients for whom 3 sets of sampling were performed: at the beginning of the treatment, after 1 week, and after 1 month. Two consecutive 8-hour sets of sampling were performed at day 0 (D0) and D7. Plasma concentrations of MPA were quantified and areas under the curve for 8hours (AUC(0-8)), and maximal and through concentrations were calculated. The results show that AUC(0-8) increases between the beginning of treatment and the end of the first week, but remains stable thereafter. Moreover, a trend to lower AUC(0-8) was observed for the patients who experienced GVHD > or =2 compared to those patients who did not. The other PK parameters are not associated with pharmacodynamic events. A limited sampling strategy with Bayesian estimators is currently under investigation to confirm these data and the role of D7 AUC(0-8) as a potential target of therapeutic drug monitoring (TDM).

Promising progression-free survival for patients low and intermediate grade lymphoid malignancies after nonmyeloablative umbilical cord blood transplantation

Nonmyeloablative hematopoietic cell transplantation (HCT) has been used to treat patients with advanced or high-risk lymphoid malignancies. We studied 65 patients (median age 46 years) receiving an umbilical cord blood (UCB) graft after a single conditioning regimen consisting of cyclophosphamide (50 mg/kg) on day -6, fludarabine (40 mg/m(2)) daily on days -6 to -2, as well as a single fraction of total-body irradiation (TBI) (200 cGy) along with cyclosporine mycophenolate mofetil immunosuppression. Median time to neutrophil and platelet recovery was 7.5 days (range: 0-32) and 46 days (range: 8-111), respectively. Cumulative incidences of grade II-IV, grade III-IV acute, and chronic graft-versus-host disease (aGVHD, cGVHD) were 57% (95% confidence interval [CI]: 43%-70%), 25% (95% CI: 14%-35%), and 19% (95% CI: 9%-29%), respectively. Transplant-related mortality at 3 years was 15% (95% CI: 5%-26%). Median follow-up was 23 months. The progression free-survival (PFS), current PFS and overall survival (OS) were 34% (95% CI: 21%-47%), 49% (95% CI: 36%-62%), and 55% (95% CI: 42%-70%) at 3 years. Based on our data, we conclude that a nonmyeloablative conditioning regimen followed by UCB transplantation is an effective treatment for patients with advanced lymphoid malignancies who lack a suitable sibling donor.