Relationship between CsA trough blood concentration and severity of acute graft-versus-host disease after paediatric stem cell transplantation from matched-sibling or unrelated donors

Higher cyclosporine-A concentration increases the risk of relapse in AML following allogeneic stem cell transplantation from unrelated donors using anti-thymocyte globulin

Cyclosporine-A (CsA) is used to prevent acute graft-versus-host disease (aGvHD). European Society for Blood and Marrow transplantation (EBMT) recommends a CsA target serum concentration of 200-300 µg/L during the first month after allogeneic hematopoietic stem cell transplantation (HSCT). With this study, we investigated whether a median CsA concentration > 200 µg/L (CsAhigh) the first month after HSCT, compared to ≤ 200 µg/L (CsAlow), increased the relapse risk of acute myloid leukemia (AML), using unrelated donors (URD) and antithymocyte globulin (ATG). Data was collected from 157 patients with AML, transplanted 2010-2016. The cumulative incidence of relapse (CIR) at 60 months was 50% in the CsAhigh versus 32% in the CsAlow group (p = 0.016). In univariate analysis, CsAhigh versus CsAlow (p = 0.028), 10-unit increase of CsA as a continuous variable (p = 0.017) and high risk disease (p = 0.003) were associated with higher CIR. The results remained after adjusting for disease risk. Death following relapse occurred more frequently in the CsAhigh group (p = 0.0076). There were no significant differences in rates of aGvHD, chronic GvHD (cGvHD), EBV/CMV-infections or overall survival (OS) between the two groups. In conclusion, we found that a median CsA concentration > 200 µg/L, the first month after HSCT, results in higher CIR of AML when combined with ATG.

Reaching the cyclosporine a level target slowly in four weeks correlates with better prognosis for Chinese patients after allogeneic haematopoietic cell transplantation

OBJECTIVES

This study investigated the impact of early cyclosporin A (CsA) initiation (day -5) on the risk of acute graft versus host disease (aGvHD) after allogeneic haematopoietic cell transplantation (allo-HSCT).

METHODS

Sixty-seven leukaemia patients who underwent allo-HSCT were investigated. The correlation between the CsA level in the first four weeks and the following indices was examined: GvHD, cumulative incidence (CI) of GvHD, CI of relapse at month 18, and non-relapse mortality (NRM) at month 18.

RESULTS

A significant association between aGvHD and CsA level in the fourth week after allo-HSCT was observed, with the incidence of aGvHD in the fourth week in the lower level group being higher than that in the higher level group (p = 0.044). The CI of aGvHD was 30.1% and 9.8% at day +90 and 42.3% and 17.1% at day +180 in the lower level and higher level groups, respectively.

CONCLUSION

For Chinese patients, early introduction and reaching the target CsA concentration within four weeks after allo-HSCT have a positive effect on preventing GvHD, especially in the fourth week after HSCT. Compared to the Western population, the target CsA concentration is lower and the time required to reach the target (within 4 weeks) is longer in the Chinese population (274.75 ng/mL).

Lower levels of cyclosporine between days 0 and +21 may reduce later relapses without increasing graft-versus-host disease in children and adolescents with acute lymphoblastic leukemia who undergo myeloablative TBI-based allogeneic hematopoietic cell transplantation

BACKGROUND

The degree of immunosuppression required for adequate graft-versus-host disease (GVHD) prevention, while keeping an adequate graft-versus-leukemia effect, in children with acute leukemia has not been established. We report the results of a retrospective comparison of cyclosporine levels and relapse rate in children and adolescents with acute lymphoblastic leukemia (ALL).

METHODS

Patients <21 y/o with ALL in remission who underwent TBI-based hematopoietic cell transplantation from related or unrelated donors between 2008 and 2021 were included. Cyclosporine levels were measured twice a week and we calculated the area under the curve (AUC) from D0 to D + 7, D + 14, and D + 21.

RESULTS

We included 76 patients. There was a trend towards a lower incidence of relapse in patients with a mean AUC < 200 ng/ml at D + 21 (HR = 0.41; p = .08). The 5-year relapse rate was 26.9% for patients with a mean AUC < 200 ng/ml at D + 21 and 43.9% for patients with a mean AUC≥200 ng/ml at D + 21. Relapse protection was restricted to relapses happening after D + 120 (HR = 0.21; p = .04).

CONCLUSIONS

Our results show evidence that pediatric patients with ALL might benefit from lower cyclosporine levels between D0 and D + 21 without a detectable increase in GVHD. Large prospective studies comparing different cyclosporine levels are awaited.

Tacrolimus initial steady state level in post-transplant cyclophosphamide-based GvHD prophylaxis regimens

Post-transplant cyclophosphamide (PTCy) combined with tacrolimus (TAC) as graft-versus-host disease (GvHD) prophylaxis post-hematopoietic cell transplantation (HCT) is safe and effective. Optimal serum levels of TAC in this combination remain undetermined. We hypothesized that TAC at initial steady state (TISS) of <10 ng/mL could promote optimal transplant outcomes and prevent TAC-associated toxicities. We retrospectively analyzed a consecutive case series of 210 patients who received PTCy/TAC-based prophylaxis post-HCT from 1/2013–6/2018. Patients received HCT from haploidentical (n=172) or mismatched donors (n=38), and flat dose (FD) or weight-based dose (WBD) TAC. Twenty-four-month overall survival (OS), disease free survival (DFS), and relapse rate (RR) were 61%, 56%, and 22%, respectively, in TISS <10 ng/mL cohort (n=176), and 50%, 43%, and 35%, respectively, in TISS ≥10 ng/mL cohort (n=34) (OS, P=0.71; DFS, P=0.097; RR, P=0.031). OS, DFS, RR, non-relapse mortality, acute GvHD grade II-IV, grade III-IV or chronic GvHD by TISS were similar in multivariable analysis. TISS ≥10 ng/mL conferred increased risk of viral infection (P=0.003). More patients receiving FD vs. WBD had TISS <10 ng/mL (P=0.001). Overall, TISS <10 ng/mL early post HCT conferred similar survival outcomes and lowered risk of viral infection and toxicities compared to TISS ≥10 ng/mL.

Impact of a Bayesian Individualization of Cyclosporine Dosage Regimen for Children Undergoing Allogeneic Hematopoietic Cell Transplantation: A Cost-Effectiveness Analysis

BACKGROUND

Cyclosporine A (CsA) is the main drug used to prevent graft-versus-host disease in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). CsA therapeutic drug monitoring (TDM) has been performed for ages, with studies revealing clinical benefits, but failing to examine its economic impact. In this article, the main objective was to evaluate the economic impact of the CsA TDM strategy, based on a Bayesian approach, by assessing costs related to its clinical impact. Furthermore, TDM effectiveness was analyzed for pharmacokinetics and clinical outcomes.

METHODS

A cost-effective, nonrandomized, retrospective, single-center study compared 2 CsA monitoring and dose adaptation strategies in pediatric patients undergoing HSCT. From 2014 to 2016, CsA TDM was performed using a population pharmacokinetics model-coupled Bayesian approach by a pharmacist ["pharmacist-assisted individualization" (PAI)]. From 2017 to 2018, CsA TDM was performed by the clinician without a Bayesian approach (non-PAI group). HSCT costs were evaluated from the French National Insurance perspective. Economic and clinical outcomes were assessed by measuring incremental cost-effectiveness ratios.

RESULTS

The study included 144 patients: 90 and 54 patients in PAI and non-PAI groups, respectively. Both groups were comparable for sociodemographic and clinical characteristics. The mean total cost per patient was significantly lower (P < 0.01) in the PAI group (€85,947) than in the non-PAI group (€100,435). Multivariate analysis revealed that TDM based on the Bayesian approach was a protective factor (odds ratio = 0.86) for severe acute graft-versus-host disease. We noted that pharmacist-based TDM was the dominant strategy. Bayesian method-based TDM allowed an increase in the percentage of target attainment at any period post-HSCT.

CONCLUSIONS

CsA TDM with a Bayesian approach is a cost-effective procedure, and highlighted clinical benefits encourage the development of new TDM strategies for HSCT.

A Clinical Decision Support Tool to Find the Best Initial Intravenous Cyclosporine Regimen in Pediatric Hematopoietic Stem Cell Transplantation

To optimize cyclosporine A (CsA) dosing regimen in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT), we aimed to provide clinicians with a validated decision support tool for determining the most suitable first dose of intravenous CsA. We used a 10-year monocentric data set of pediatric patients undergoing HSCT. Discretization of all variables was performed according to literature or thanks to algorithms using Shannon entropy (from information theory) or equal width intervals. The first 8 years were used to build the Bayesian network model. This model underwent a 10-fold cross-validation, and then a prospective validation with data of the last 2 years. There were 3.3% and 4.1% of missing values in the training and the validation data set, respectively. After prospective validation, the Tree-Augmented Naïve Bayesian network shows interesting prediction performances with an average area under the receiver operating characteristic curve of 0.804, 32.8% of misclassified patients, a true-positive rate of 0.672, and a false-positive rate of 0.285. This validated model allows good predictions to propose an optimized and personalized initial CsA dose for pediatric patients undergoing HSCT. The clinical impact of its use should be further evaluated.

Initial dosage optimization of ciclosporin in pediatric Chinese patients who underwent bone marrow transplants based on population pharmacokinetics

Bone marrow transplants (BMT) are an established therapeutic strategy for patients with severe aplastic anemia, acute lymphoblastic leukemia, acute myeloid leukemia or chronic myeloid leukemia. However, the successful application of BMT is limited by graft-vs.-host disease (GVHD). Ciclosporin has been widely used for treating GVHD in pediatric patients who underwent BMT. The present study aimed to optimize the dosage of ciclosporin for safety and effectiveness based on population pharmacokinetics. A non-linear mixed-effects model was used to analyze the clinical data of pediatric patients who underwent BMT between September 2016 and September 2019 at the Children's Hospital of Fudan University. Monte Carlo simulations were used to identify the optimal dose of ciclosporin. The final population pharmacokinetic model indicated that body weight and days post-transplant influenced the clearance of ciclosporin in pediatric patients who underwent BMT. The present study indicated that the optimal initial dose of ciclosporin for pediatric patients weighing 5-30 kg who underwent BMT was 6 mg/kg/day split into 2 doses.

A decision support tool to find the best cyclosporine dose when switching from intravenous to oral route in pediatric stem cell transplant patients

PURPOSE

Managing the pharmacokinetic variability of immunosuppressive drugs after pediatric hematopoietic stem cell transplantation (HSCT) is a clinical challenge. Thus, the aim of our study was to design and validate a decision support tool predicting the best first cyclosporine oral dose to give when switching from intravenous route.

METHODS

We used 10-years pediatric HSCT patients' dataset from 2008 to 2018. A tree-augmented naïve Bayesian network model (method belonging to artificial intelligence) was built with data from the first eight-years, and validated with data from the last two.

RESULTS

The Bayesian network model obtained showed good prediction performances, both after a 10-fold cross-validation and external validation, with respectively an AUC-ROC of 0.89 and 0.86, a percentage of misclassified patients of 28.7% and 35.2%, a true positive rate of 0.71 and 0.65, and a false positive rate of 0.12 and 0.14 respectively.

CONCLUSION

The final model allows the prediction of the most likely cyclosporine oral dose to reach the therapeutic target specified by the clinician. The clinical impact of using this model needs to be prospectively warranted. Respecting the decision support tool terms of use is necessary as well as remaining critical about the prediction by confronting it with the clinical context.

Low cyclosporine concentrations in children and time to acute graft versus host disease

Background

Achievement of target blood concentrations of cyclosporine (CsA) early after transplantation is known to be highly effective for reducing the incidence of acute graft versus host disease (aGVHD). However, no research has been conducted for predicting aGVHD occurrence with low CsA concentrations at different time periods. The objective of this study was to investigate the risk of aGVHD according to low CsA concentrations at lag days in children with allogenic hematopoietic stem cell transplantation (HSCT).

Methods

The records of 61 consecutive children who underwent allogeneic HSCT and received CsA as prophylaxis against aGVHD between May 2012 and March 2015 were retrospectively evaluated. The main outcome was any association between low CsA concentrations at lag days and aGVHD occurrence, which was examined for the first month after transplantation. Mean CsA concentrations at three lag periods were calculated: lag days 0–6, 7–13, and 14–20 before aGVHD occurrence.

Results

Patients whose mean CsA concentrations at lag days 0–6 did not reach the initial target concentration had 11.0-fold (95% confidence interval [CI]: 2.3–51.9) greater incidence of aGVHD. In addition, the AORs of low CsA concentrations at lag days 7–13 and 14–20 for developing aGVHD were 108.2 (95% CI: 7.7–1515.5) and 12.1 (95% CI: 1.1–138.1), respectively.

Conclusions

After low CsA concentrations are detected, careful attention needs to be paid to prevent aGVHD.

Extended CCR5 Blockade for Graft-versus-Host Disease Prophylaxis Improves Outcomes of Reduced-Intensity Unrelated Donor Hematopoietic Cell Transplantation: A Phase II Clinical Trial

Graft-versus-host disease (GVHD) remains the most common treatment-related complication after allogeneic hematopoietic cell transplantation (allo-HCT). Lymphocyte migration plays a critical role in the pathogenesis of GVHD. A previous phase I/II trial demonstrated that CCR5 blockade with maraviroc in the first 30days after allo-HCT resulted in a low incidence of early acute GVHD, primarily in visceral organs, but with no impact on late acute or chronic GVHD. We conducted a phase II trial to examine the efficacy of an extended course of maraviroc, administered through post-transplantation day +90 in addition to standard prophylaxis in 37 recipients of reduced-intensity-conditioned unrelated donor allo-HCT performed to treat hematologic malignancies. Extended maraviroc treatment was safe and feasible. The primary study endpoint, day +180 rate of grade II-IV acute GVHD, was 22 ± 7%, liver GVHD was not observed, and gut GVHD was uncommon. The day +180 rate of grade III-IV acute GVHD was 5 ± 4%. The 1-year rate of moderate to severe chronic GVHD was 8 ± 5% and that of disease relapse was 30 ± 8%. Overall survival at 1 year was 70 ± 8%. Compared with the previously studied short course of maraviroc, the extended course resulted in a significantly higher GVHD-free, relapse-free survival (adjusted hazard ratio [HR], .45; 95% confidence interval [CI], .25 to .82; P = .009) and overall survival (adjusted HR, .48; 95% CI, .24 to .96; P = .037). A combined analysis of both trials showed that high maraviroc trough concentrations on the day of hematopoietic cell infusion were associated with lower rates of acute GVHD. An extended course of maraviroc after reduced-intensity-conditioned unrelated donor allo-HCT is safe and effective in preventing acute and chronic GVHD and is associated with favorable survival.

Bayesian Networks: A New Approach to Predict Therapeutic Range Achievement of Initial Cyclosporine Blood Concentration After Pediatric Hematopoietic Stem Cell Transplantation

BACKGROUND

Pediatric hematopoietic stem cell transplantation (HSCT) allows the treatment of numerous diseases, both malignant and non-malignant. Cyclosporine, a narrow therapeutic index drug, is the major immunosuppressant used to prevent graft-versus-host disease (GVHD), but may also cause severe adverse effects in case of overdosing.

OBJECTIVE

The objective of this study is to predict the initial cyclosporine residual blood concentration value after pediatric HSCT, and consequently the dose necessary to reach the therapeutic range, using a mathematical individual predictive model.

METHODS

Clinical and biological data collected from the graft infusion for 2 months after transplantation in 155 pediatric patients undergoing HSCT between 2008 and 2016 were used to generate synthetic data for 1000 subjects which were used to build a Bayesian network model. We compared the characteristics and sensitivity to clinical or biological missing data of this model with four other methods.

RESULTS

The tree-augmented Naïve Bayesian network showed the best characteristics, with no missing data (area under the curve of the receiving operator characteristics curve [AUC-ROC] of 0.89 ± 0.02), 18.9 ± 2.6% of patients misclassified, and positive and negative predictive values of 85.9 ± 3.4% and 74.2 ± 5.1%, respectively, and this trend is found in the synthetic dataset from no to 10% missing data. The most relevant variables that could influence whether the initial residual cyclosporine concentration is in the therapeutic range are the last dose before measurement and the mean dose before measurement.

CONCLUSIONS

We developed and cross-validated an online Bayesian network to predict the first cyclosporine concentration after pediatric HSCT. This model allows simulation of different dosing regimens, and enables the best dosing regimen to reach the therapeutic range immediately after transplantation to be found, minimizing the risk of adverse effects and GVHD occurrence.

Relationship between cyclosporine area-under-the curve and acute graft versus host disease in pediatric patients undergoing hematopoietic stem cell transplant: A prospective, multicenter study

Traditionally in hematopoietic stem cell transplant (HSCT), cyclosporine doses are individualized using cyclosporine trough concentrations (C₀) while area under the concentration vs time curve (AUC) is used in solid organ transplant. AUC potentially has an important relationship with the development of acute graft-versus-host-disease (aGVHD). We conducted a prospective study to describe the relationship between severe (grade III-IV) aGVHD and cyclosporine AUC in pediatric HSCT recipients. Pediatric patients who underwent allogeneic myeloablative HSCT and scheduled to receive cyclosporine for aGVHD prophylaxis participated in this multicenter study. Cyclosporine doses were adjusted based on C₀ according to each center's standard of care. Cyclosporine AUC was determined weekly until neutrophil engraftment or Day +42, whichever was later. Associations between severe aGVHD and cyclosporine AUC and other patient and treatment-related factors were evaluated. Of the 110 children enrolled, 97 were evaluable. Thirty-seven (38%) children developed aGVHD; 13 (13.4%) had severe aGVHD. On univariate analysis, there was no association between severe aGVHD and cyclosporine AUC at any time point before engraftment. Future research should focus on refinement of C₀ targets for cyclosporine therapeutic drug monitoring in HSCT.

Pharmacokinetic comparison of cyclosporin A and tacrolimus in graft-versus-host disease prophylaxis

A number of studies were published with contradictory results comparing tacrolimus (Tac) and cyclosporine A (CsA) for graft-versus-host disease (GVHD) prophylaxis, but there are only few that accounted for pharmacokinetic (PK) parameters. In this study, we created a model based on median concentrations, variability of concentrations, and failures to maintain target levels that distinguished patients with low, intermediate, and high risks of acute GVHD (hazard ratios (HR) 1.77, 95%CI 1.36-2.32, p < 0.0001). This model was used to compare 95 patients with CsA and 239 with Tac GVHD prophylaxis. In the multivariate analysis, incorporating PK risk, no differences were observed for grade II-IV acute GVHD (HR 0.73, 95%CI 0.48-1.10, p = 0.13), but grade III-IV acute GVHD was lower in the Tac group (HR 0.47, 95%CI 0.28-0.78, p = 0.004). The observed difference was due to patients with high PK risk (HR 0.377, 95%CI 0.19-0.75, p = 0.005), but not with low and intermediate PK risk (p > 0.05). Patients in the Tac group had better GVHD relapse-free survival (HR = 0.659, p = 0.01) and comparable overall survival (p > 0.05). In conclusion, PK risk should be accounted for in comparisons of GVHD prophylaxis regimens with calcineurin inhibitors, and Tac was superior to CsA in patients with high, but not intermediate and low PK risk.

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.

Cyclosporine use in hematopoietic stem cell transplantation: pharmacokinetic approach

Cyclosporine is one of the most vital agents in the process of successful allogeneic hematopoietic stem cell transplantation. Despite a long history and worldwide extent of cyclosporine use for prevention of graft versus host disease, currently there are lots of uncertainties about its optimal method of application to reach the best clinical outcome. A major portion of this problem stems from complicated cyclosporine pharmacokinetics. Study of cyclosporine pharmacokinetic behavior can significantly help recognition of its effectiveness and consequently, optimization of dosing, administration, monitoring and management of adverse effects. In this review, highly accredited but sparse scientific data are gathered in order to provide a better insight for preparation of practice guidelines and directing future studies for allogeneic hematopoietic cell recipients.

Pharmacokinetic drug-drug interaction of calcium channel blockers with cyclosporine in hematopoietic stem cell transplant children

BACKGROUND

Cyclosporine (CsA) is frequently responsible for hypertension in bone marrow transplant children. Calcium channel blockers (CCBs) are considered to be the best treatment for CsA-induced hypertension, but they may alter the exposure and the effect of CsA by inhibiting the CYP3A4 pathway of CsA metabolism or P-gp. However, the inhibitory effect on CYP3A4 may vary among CCBs.

METHODS

This study aimed to quantify the pharmacokinetic drug-drug interaction between CsA and nicardipine, amlodipine, and lacidipine. In all, 51 children who received CsA and CCB concomitantly were included.

RESULTS

Dose-normalized CsA trough blood concentrations significantly increased in patients treated with nicardipine and amlodipine, whereas they remained stable in patients treated with lacidipine.

CONCLUSIONS

Because lacidipine appears to have no effect on CsA exposure, it may be the best option among CCBs for treating high blood pressure caused by CsA in children.

Impact of cyclosporine levels on the development of acute graft versus host disease after reduced intensity conditioning allogeneic stem cell transplantation

We analyze the impact of cyclosporine (CsA) levels in the development of acute graft-versus-host disease (aGVHD) after reduced intensity conditioning allogeneic hematopoietic transplantation (allo-RIC). We retrospectively evaluated 156 consecutive patients who underwent HLA-identical sibling allo-RIC at our institution. CsA median blood levels in the 1st, 2nd, 3rd and 4th weeks after allo-RIC were 134 (range: 10–444), 219 (54–656), 253 (53–910) and 224 (30–699) ng/mL; 60%, 16%, 11% and 17% of the patients had median CsA blood levels below 150 ng/mL during these weeks. 53 patients developed grade 2–4 aGVHD for a cumulative incidence of 45% (95% CI 34–50%) at a median of 42 days. Low CsA levels on the 3rd week and sex-mismatch were associated with the development of GVHD. Risk factors for 1-year NRM and OS were advanced disease status (HR: 2.2, P = 0.02) and development of grade 2–4 aGVHD (HR: 2.5, P < 0.01), while there was a trend for higher NRM in patients with a low median CsA concentration on the 3rd week (P = 0.06). These results emphasize the relevance of sustaining adequate levels of blood CsA by close monitoring and dose adjustments, particularly when engraftment becomes evident. CsA adequate management will impact on long-term outcomes in the allo-RIC setting.

Effect of posaconazole on cyclosporine blood levels and dose adjustment in allogeneic blood and marrow transplant recipients

The posaconazole prescribing information recommends an upfront cyclosporine dose reduction upon initiation of posaconazole prophylaxis. We examined this recommendation in the early phase of allogeneic transplantation, where cyclosporine levels potentially becoming subtherapeutic following upfront dose reduction would be deleterious to transplant outcome. Our data show that while posaconazole leads to an increase in cyclosporine levels, subsequent cyclosporine dose reduction can be safely guided by therapeutic drug monitoring and is not required upfront. Therefore, the current recommendation may be modified.

The effect of cyclosporine initiation time on the outcome of matched allogeneic stem-cell transplantation following fludarabine-based conditioning

Cyclosporine (CSA) is the most commonly used medication for GVHD prophylaxis. The initiation time varies from day -4 to day 0. Initially, we gave CSA starting on day -1. However, since 2003 we have changed CSA initiation timing policy in most of our protocols to day -4, to achieve stable and controlled pretransplant CSA levels. Here, we assessed if initiation time impact the outcome of allogeneic stem-cell transplantation (allo-SCT). Data of 261 patients who underwent allo-SCT for hematological malignancies from a fully matched donor, treated with CSA as a single agent for GVHD prophylaxis were prospectively collected. Patients were divided according to CSA initiation time and analyzed for outcome. The acute GVHD severity, cGVHD extent, GVHD-associated mortality were significantly lower in the CSA -4 group. There was no difference in the rate and timing of acute or chronic GVHD. Overall survival did not differ between the groups. We conclude that the initiation of CSA at day -4 reduced the severity of aGVHD, extent of cGVHD, and GVHD-associated mortality without impact on overall survival.

Cyclosporine area under the curve after allogeneic hematopoietic stem cell transplantation is an indicator of Epstein-Barr virus DNAemia

Epstein-Barr virus (EBV) DNAemia and reactivation is a typical complication after allogeneic hematopoietic stem cell transplantation (HSCT). The degree of immunosuppression is closely linked to the risk of developing EBV DNAemia. An association of cyclosporine levels with EBV DNAemia has not been interrogated. Here, we analyzed cyclosporine levels in 58 patients after allogeneic HSCT. We discovered a wide range of cyclosporine trough level variation in the individual patient (median coefficient of variation [CV] 0.29, range 0.19-0.78). To overcome this high intra-individual variation in serum trough levels of cyclosporine, we calculated respective areas under the curve (AUC) and performed correlations with EBV DNAemia in 28 stem cell recipients at increased risk for EBV DNAemia. This resulted in a significant association of high cyclosporine AUC (> 6000 ng/mL × days) with EBV DNAemia after day 30 (relative risk [RR] 6.067, 95% confidence interval [CI] 1.107-33.238, p = 0.038). Conversely, mean cyclosporine values (threshold 200 ng/mL) between days 0 and 30 were not found to correlate with EBV DNAemia after day 30. Furthermore, CD3 + CD8 + graft content was inversely correlated with EBV DNAemia after day 30. These findings might establish a clinical role for the AUC of cyclosporine.

Association between calcineurin inhibitor blood concentrations and outcomes after allogeneic hematopoietic cell transplantation

To determine whether calcineurin inhibitor (CNI) blood concentrations within the first month after allogeneic hematopoietic cell transplantation (HCT) correlated with the incidence of graft-versus-host disease (GVHD) and other outcomes, we retrospectively analyzed data from 1181 patients with hematologic malignancies who had HCT from HLA-matched related (n = 634) or unrelated (n = 547) donors at a single institution between 2001 and 2009. After myeloablative HCT (n = 774), higher CNI concentrations were not associated with lower risks of acute or chronic GVHD (aGVHD, cGVHD). After nonmyeloablative HCT (n = 407), higher cyclosporine concentrations were associated with decreased risks of grade 2-4 and 3-4 aGVHD (hazard ratio [HR] per 100 ng/mL change in cyclosporine concentrations, 0.7; 95% confidence interval [CI], 0.6-0.82; and HR, 0.66, 95% CI, 0.49-0.9, respectively), nonrelapse mortality (HR, 0.6, 95% CI, 0.41-0.88), and overall mortality (HR, 0.83, 95% CI, 0.71-0.99). Cyclosporine concentrations were not associated with risks of cGVHD and recurrent malignancy after nonmyeloablative HCT. Among patients given tacrolimus after nonmyeloablative HCT, a similar trend of CNI-associated GVHD-protection was observed. Higher CNI concentrations were not associated with apparent renal toxicity. We conclude that higher cyclosporine concentrations relatively early after nonmyeloablative HCT confer protection against aGVHD that translates into reduced risks of nonrelapse and overall mortality.

Impact of cyclosporine-A concentration on the incidence of severe acute graft-versus-host disease after allogeneic stem cell transplantation

This single-center retrospective study analyzed 85 consecutive patients who underwent allogeneic stem cell transplantation (allo-SCT) with the aim to assess whether there is a correlation between exposure to cyclosporine-A (CsA; as measured by CsA concentrations during the first month after allo-SCT) and the risk for developing severe grade III-IV acute graft-versus-host disease (aGVHD). The median concentrations of CsA in the blood at 1, 2, 3, and 4 weeks after allo-SCT were 348 (range: 172-733), 284 (range: 137-535), 274 (range: 107-649), and 247 (range: 37-695) ng/mL, respectively. Overall, grade II-IV aGVHD occurred in 36 patients (42%) at a median of 29 (range: 6-100) days after allo-SCT. The incidence of grade III-IV aGVHD (n = 20) was 23% (95% confidence interval [CI], 14%-32%). In univariate analysis, patients receiving allo-SCT from an HLA-matched unrelated donor had a higher risk of grade III-IV aGVHD, and patients having the lowest CsA concentration in the first and second weeks after allo-SCT had a significantly higher risk of grade III-IV aGVHD. In a multivariate logistic regression analysis, a higher CsA concentration measured during the first week following graft infusion was the strongest parameter significantly associated with a reduced risk of severe grade II-IV aGVHD (P = .012; relative risk [RR] = 0.24; 95% CI, 0.08-0.73). Of note, when adjusted by donor type, CsA concentration in week 1 remained significantly associated with risk of severe grade II-IV aGVHD (P = .014). We conclude that precise monitoring of CsA concentrations and adjustment of CsA dose early after allo-SCT may be effective to prevent onset of severe aGVHD.

The use of pharmacokinetic models in paediatric onco-haematology: effects on clinical outcome through the examples of busulfan and cyclosporine

Overall survival after allogeneic haematopoietic stem cell transplantation (HSCT) is reduced by the high rate of transplantation-related mortality (TRM), especially because of liver veno-occlusive disease (VOD) or acute graft-vs.-host disease (GVHD) because of the toxicity or inefficacy of busulfan and cyclosporine (CsA), respectively. Results of clinical outcome of previous studies performed to optimize busulfan and CsA therapy by controlling their pharmacokinetic variability by means of maximum a posteriori (MAP) Bayesian individualization of both drugs are presented. The 90-day VOD-free survival was significantly higher in patients with individualized busulfan doses: 97% vs. 76%. Monitoring CsA trough blood concentrations allowed us to obtain a successful GVHD outcome (mild or moderate GVHD and graft vs. leukaemia effect (GVL) in malignant diseases and no GVHD (in non-malignant ones) in the majority of our patients. Severe GVHD occurred in <5% of patients. TRM in children can be significantly decreased by using population pharmacokinetic models and MAP Bayesian individualization of dose regimens for drugs such as CsA and busulfan.

Decreased incidence of acute graft-versus-host disease by continuous infusion of cyclosporine with a higher target blood level

Cyclosporine A (CsA) is the mainstay of pharmacologic prevention of acute graft-versus-host disease (GVHD). We previously reported that continuous infusion of CsA with a target blood level between 250 and 400 ng/ml significantly increased the incidence of acute GVHD compared to twice-daily infusion with a target trough level between 150 and 300 ng/ml. Thus, we raised the target level of CsA continuous infusion to 450-550 ng/ml. We treated 33 patients with the higher target level (CsA500) and compared the efficacy and toxicity with those in the 33 historical control patients (CsA300 group). Other transplantation procedures were not changed. The patients' characteristics were equivalent. The average CsA concentration was adjusted around 500 ng/ml and the actual daily dose was maintained at the initial dose (CsA 3mg/kg/day). Toxicities were equivalently observed among the two groups. The incidence of grades II-IV acute GVHD was significantly lower in the CsA500 group (27 vs. 52%, P = 0.033). The target level of CsA was identified as an independent significant risk factor for grades II-IV acute GVHD (P = 0.039), adjusted for the presence of HLA mismatch. The incidence of chronic GVHD was also decreased in the CsA500 group (47 vs. 73%, P = 0.016). We conclude that the toxicity of the continuous CsA infusion with a target level of 450-550 ng/ml is acceptable and the efficacy to prevent acute GVHD is significant. A larger comparative study is warranted to confirm these findings.

Risk factors for acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation: retrospective analysis of 73 patients who received cyclosporin A

Cyclosporin A (CsA) has been used most widely as an immunosuppressive agent for preventing graft-versus-host disease (GVHD). To explore the risk factors including CsA blood levels for grades II-IV acute GVHD, we retrospectively analyzed the data of patients who underwent allogeneic hematopoietic stem cell transplantation in our hospital between March 1989 and July 2001. Seventy-three patients (47 males and 26 females) received CsA and short-term methotrexate for GVHD prophylaxis. CsA 1.5 mg/kg was administered as a 3-h infusion twice daily from day 1 until the patient recovered from the toxic gastrointestinal complication. Methotrexate was given at a dose of 15 mg/m(2) on day 1 and 10 mg/m(2) on days 3, 6 and 11. Grades II-IV acute GVHD occurred in 18 patients (24.7%). Multivariate Cox regression analysis revealed that higher C(5) (the whole-blood CsA concentration at 5 h after the start of infusion) before the onset of acute GVHD reduced the onset of grades II-IV acute GVHD with a hazard ratio of 0.994 (95% confidence interval 0.989-0.999) for every increase of 1 ng/ml. Our data indicate that inadequate exposures of CsA can be a vital risk for developing acute GVHD. From our results, we consider that precise monitoring of CsA concentrations and adjustment of CsA dose using the concentration may be effective to prevent the onset of severe acute GVHD. To confirm this finding, further prospective study will be needed.

Exposure-effect population model of inolimomab, a monoclonal antibody administered in first-line treatment for acute graft-versus-host disease

BACKGROUND AND OBJECTIVE

Inolimomab, a monoclonal antibody against interleukin (IL)-2Ralpha (CD25) has shown promising results in the treatment of corticosteroid-resistant acute graft-versus-host disease (GvHD). The objective of the present study was to characterise the pharmacokinetic and pharmacodynamic properties of inolimomab as first-line treatment in this condition.

METHODS

The data came from 21 patients with acute GvHD (8 with an International Bone Marrow Transplant Registry [IBMTR] score of B, 11 with a score of C and 2 with a score of D) following haematopoietic stem cell transplantation after a median delay of 26 days (range 10-127 days). Inolimomab was administered at 0.1, 0.2, 0.3 or 0.4 mg/kg daily in association with methylprednisolone (2 mg/kg) for 8 or 16 days depending on the status at day 9. Then, for responder patients, administrations were continued three times weekly until day 28. Inolimomab concentrations and pharmacodynamic data (acute GvHD scores) were recorded during the study. The pharmacodynamic data were assessed in four grades according to the IBMTR and Glucksberg classification in parallel with Karnofsky scores. A population analysis was developed using a nonlinear mixed-effects model to define the pharmacokinetic model, to test covariates and, when apparent, to model the exposure-effect relationship by a proportional odds model. The modelling was finally qualified by a predictive check.

RESULTS

The best pharmacokinetic model was two-compartmental. For each score, the most demonstrative exposure-effect graphics linked the cumulative area under the concentration-time curve to cumulated probabilities of observing a specific score. This relationship was identified as a maximum effect model for the skin (with two patient subpopulations: sensitive/less sensitive) and a linear model for the intestinal tract and liver. No covariate was identified as influencing any of these parameters.

CONCLUSION

Inolimomab exposure-effect relationships as first-line treatment for acute GvHD have been identified and modelled. The discovered dose-effect relationship allows confirmation of the treatment response, thereby establishing the first step towards optimising the inolimomab dosage in future trials.

Disposition of two oral formulations of cyclosporine in pediatric patients receiving hematopoietic stem cell transplants

STUDY OBJECTIVES

To compare the disposition of cyclosporine after the administration of two oral formulations to children undergoing hematopoietic stem cell transplantation, and to evaluate the relationship between whole blood cyclosporine concentrations during the dosing interval and the area under the whole blood concentration-time curve.

DESIGN

Prospective, descriptive, crossover study.Setting. Hematopoietic stem cell transplantation unit in a tertiary-quaternary university-affiliated pediatric hospital.

PATIENTS

Twenty-four pediatric patients aged 0.5-16.9 years undergoing allogeneic hematopoietic stem cell transplantation.

INTERVENTION

The modified oral formulation of cyclosporine was given on the first day (divided as two doses), and a single identical dose of the original oral formulation was given on the morning of the second day.

MEASUREMENTS AND MAIN RESULTS

Blood samples were obtained at 0, 0.5, 1.25, 2, 4, 6, 9, and 12 hours after the morning dose from the lumen of the central venous catheter not previously used for intravenous cyclosporine administration. Cyclosporine concentration-time data were analyzed by using noncompartmental methods. Mean +/- SD maximum concentrations were significantly higher after administration of the modified form than after administration of the original form (594.9 +/- 349.7 vs 483.0 +/- 363.0 microg/L, p=0.003), as was the area under the concentration-time curve from 0-12 hours (AUC0-12; 3432 +/- 1563 vs 3144 +/- 1780 microg/L x hr, p=0.022). For both formulations, cyclosporine concentrations at 4 hours after administration were most strongly correlated with the AUC0-12. Unlike that of the original formulation, the trough cyclosporine concentration of the modified form had the weakest relationship with AUC (Spearman rho coefficient 0.584, p=0.003).

CONCLUSION

Cyclosporine absorption is lower in children undergoing hematopoietic stem cell transplantation than in children receiving solid organ transplants. Dosage adjustment for the modified formulation based on trough concentration may not be appropriate because its relationship with the AUC was weak. The link between pharmacokinetic parameters and clinical outcomes, such as graft-versus-host disease, must be further studied.

[Busulfan and cycosporin in bone graft children]

Most drugs exhibit both inter- and intra-individual pharmacokinetic and pharmacodynamic variability. This variability explains the different responses observed in patients exposed to standard doses and must be taken into consideration when the therapeutic window is narrow. Population pharmacokinetics provides mean (or median) values of pharmacokinetic parameters as well as the distribution pattern and the statistical relationship with covariables in a group of individuals presenting common characteristics. Among the different methods developed for population pharmacokinetics, the data pool method, as well as the two-step and one-step methods (NONMEM and NPEM) are attractive. Population models can then be developed using bayesian logistics to obtain an estimation of the pharmacokinetic parameters of a given patient and predict the most adapted dose in light of the therapeutic target (residual serum concentration, mean concentration.). Busulfan is an alkylizing agent used instead of radiotherapy for pre-graft preparation before bone marrow grafts in children. This compound requires dose monitoring because of its narrow therapeutic window: under-dosing raises the risk of graft rejection; inversely over-dosing can cause potentially fatal complications such as occlusive venous disease. Interindividual variability is characteristic of busulfan kinetics. Several factors can explain part of this variability: age, underlying disease, changes in liver function, drug bioavailability, chronobiology. The short treatments used (most protocols have 16 doses given in four days) require rapid monitoring to propose effective adjustments. In this context, use of bayesian logistics to estimate the patient's pharmokinetic parameters is very useful for correct dosing. This type of monitoring could also be used for other compounds such as cyclosporine, with a narrow therapeutic window.