Higher tacrolimus concentrations early after transplant reduce the risk of acute GvHD in reduced-intensity allogeneic stem cell transplantation

Clinical effects of tacrolimus blood concentrations early after allogeneic hematopoietic stem cell transplantation

BACKGROUND AIMS

Tacrolimus (TAC) plus short-term methotrexate (stMTX) is used for graft-versus-host disease (GVHD) prophylaxis after allogeneic hematopoietic stem cell transplantation (allo-HSCT). TAC blood concentrations are frequently adjusted to enhance the graft-versus-leukemia/lymphoma effect or attenuate severe GVHD. Limited information is available on the clinical impact of these adjustments and the optimal time to perform them in order to achieve good clinical outcomes.

METHODS

We retrospectively analyzed 211 patients who underwent allo-HSCT at our institutes.

RESULTS

Higher TAC concentrations in week 3 correlated with a significantly higher cumulative incidence of relapse (CIR) (P = 0.03) and lower nonrelapse mortality (P = 0.04). The clinical impact of high TAC concentrations in week 3 on CIR was detected in the refined disease risk index: low/intermediate (P = 0.04) and high (P < 0.01), and conditioning regimens other than cyclophosphamide/total body irradiation and busulfan/cyclophosphamide (P = 0.07). Higher TAC concentrations in week 1 correlated with a lower grade 2-4 acute GVHD rate (P = 0.01). Higher TAC concentrations in weeks 2 and 3 correlated with slightly lower (P = 0.05) and significantly lower (P = 0.02) grade 3-4 acute GVHD rates, respectively. Higher TAC concentrations in weeks 1 and 3 were beneficial for severe acute GVHD in patients with a human leukocyte antigen-matched donor (P = 0.03 and P < 0.01, respectively), not treated with anti-thymocyte globulin (P = 0.02 and P = 0.02, respectively), and receiving three stMTX doses (P = 0.03 and P = 0.02, respectively).

CONCLUSIONS

The clinical impact of TAC concentrations varied according to patient characteristics, including disease malignancy, conditioning regimens, donor sources, and GVHD prophylaxis. These results suggest that TAC management needs to be based on patient profiles.

Effects of CYP3A5 Genotype on Tacrolimus Pharmacokinetics and Graft-versus-Host Disease Incidence in Allogeneic Hematopoietic Stem Cell Transplantation

Tacrolimus (Tac) is pivotal in preventing acute graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (alloHSCT). It has been reported that genetic factors, including CYP3A5*3 and CYP3A4*22 polymorphisms, have an impact on Tac metabolism, dose requirement, and response to Tac. There is limited information regarding this topic in alloHSCT. The CYP3A5 genotype and a low Tac trough concentration/dose ratio (Tac C0/D ratio) can be used to identify fast metabolizers and predict the required Tac dose to achieve target concentrations earlier. We examined 62 Caucasian alloHSCT recipients with a fast metabolizer phenotype (C0/dose ratio ≤ 1.5 ng/mL/mg), assessing CYP3A5 genotypes and acute GVHD incidence. Forty-nine patients (79%) were poor metabolizers (2 copies of the variant *3 allele) and 13 (21%) were CYP3A5 expressers (CYP3A5*1/*1 or CYP3A5*1/*3 genotypes). CYP3A5 expressers had lower C0 at 48 h (3.7 vs. 6.2 ng/mL, p = 0.03) and at 7 days (8.6 vs. 11.4 ng/mL, p = 0.04) after Tac initiation, tended to take longer to reach Tac therapeutic range (11.8 vs. 8.9 days, p = 0.16), and had higher incidence of both global (92.3% vs. 38.8%, p < 0.001) and grade II-IV acute GVHD (61.5% vs. 24.5%, p = 0.008). These results support the adoption of preemptive pharmacogenetic testing to better predict individual Tac initial dose, helping to achieve the therapeutic range and reducing the risk of acute GVHD earlier.

Association between CYP3A4, CYP3A5 and ABCB1 genotype and tacrolimus treatment outcomes among allogeneic HSCT patients

Aim: Successful treatment with tacrolimus to prevent graft versus host disease (GVHD) and minimize tacrolimus-related toxicities among allogeneic hematopoietic cell transplantation (alloHCT) recipients is contingent upon quickly achieving and maintaining concentrations within a narrow therapeutic range. The primary objective was to investigate associations between CYP3A4, CYP3A5 or ABCB1 genotype and the proportion of patients that attained an initial tacrolimus goal concentration following initiation of intravenous (iv.) and conversion to oral administration. Materials & methods: We retrospectively evaluated 86 patients who underwent HLA-matched (8/8) related donor alloHCT and were prescribed a tacrolimus-based regimen for GVHD prophylaxis. Results & conclusion: The findings of the present study suggests that CYP3A5 genotype may impact attainment of initial therapeutic tacrolimus concentrations with oral administration in alloHCT recipients.

Impact of Early Intrapatient Variability of Tacrolimus Concentrations on the Risk of Graft-Versus-Host Disease after Allogeneic Stem Cell Transplantation Using High-Dose Post-Transplant Cyclophosphamide

Tacrolimus (Tac) is a pivotal immunosuppressant agent used to prevent graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (alloHSCT). Tac is characterized by a narrow therapeutic window and a high inter-patient and intra-patient pharmacokinetic variability (IPV). Although high IPV of Tac concentrations has been associated with adverse post-transplant outcomes following solid organ transplantation, the effects of Tac IPV on alloHSCT recipients have not been determined. Tac IPV was therefore retrospectively evaluated in 128 alloHSCT recipients receiving high-dose post-transplant cyclophosphamide (PTCy) and the effects of Tac IPV on the occurrence of acute GVHD (aGVHD) were analyzed. Tac IPV was calculated from pre-dose concentrations (C0) measured during the first month after Tac initiation. The cumulative rates of grades II-IV and grades III-IV aGVHD at day +100 were 22.7% and 7%, respectively. Higher Tac IPV was associated with a greater risk of developing GVHD, with patients having IPV > 50th percentile having significantly higher rates of grades II-IV (34.9% vs. 10.8%; hazard ratio [HR] 3.858, p < 0.001) and grades III-IV (12.7% vs. 1.5%; HR 9.69, p = 0.033) aGVHD than patients having IPV ≤ 50th percentile. Similarly, patients with IPV > 75th percentile had higher rates of grades II-IV (41.9% vs. 16.5%; HR 3.30, p < 0.001) and grades III-IV (16.1% vs. 4.1%; HR 4.99, p = 0.012) aGVHD than patients with IPV ≤ 75th percentile. Multivariate analyses showed that high Tac IPV (>50th percentile) was an independent risk factor for grades II-IV (HR 2.99, p = 0.018) and grades III-IV (HR 9.12, p = 0.047) aGVHD. Determination of Tac IPV soon after alloHSCT could be useful in identifying patients at greater risk of aGVHD.

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.

[The effect of CYP3A5 gene polymorphism on tacrolimus concentration and adverse events in patients undergoing allogeneic hematopoietic stem cell transplantation]

目的

探讨在异基因造血干细胞移植（allo-HSCT）患者中，CYP3A5基因多态性与他克莫司血药浓度及急性移植物抗宿主病（GVHD）间的关系。

方法

回顾性分析2019年7月至2020年2月在中国医学科学院血液病医院接受allo-HSCT的35例中国成人患者。移植前采集骨髓进行CYP3A5基因分型。应用静脉输注他克莫司、短疗程甲氨蝶呤（MTX）±吗替麦考酚酯进行GVHD预防。在他克莫司用药第2天或第3天监测初始血药浓度，随后每周监测2～3次。根据目标血药浓度（10～15 ng/ml）调整药物剂量。

结果

16例携带CYP3A5*3/*3基因的allo-HSCT患者的初始他克莫司血药浓度（9.82 ng/ml对8.53 ng/ml）、初始血药浓度/剂量（C/D）比值（5.72 ng·ml⁻¹·mg⁻¹对4.26 ng·ml⁻¹·mg⁻¹）、allo-HSCT后第一和第二周C/D比值中位数（5.29 ng·ml⁻¹·mg⁻¹对4.61 ng·ml⁻¹·mg⁻¹，5.65 ng·ml⁻¹·mg⁻¹对4.56 ng·ml⁻¹·mg⁻¹）均明显高于19例至少携带一个CYP3A5*1等位基因的患者（P值分别为0.028、0.001、0.037、0.045）。至少携带一个CYP3A5*1等位基因的患者，allo-HSCT后Ⅲ～Ⅳ级急性GVHD的发生率有高于携带CYP3A5*3/*3基因患者的趋势［（26.3±10.1）％对（6.2±6.1）％，P＝0.187］。

结论

CYP3A5基因型导向给药可能有助于allo-HSCT后更快地达到他克莫司目标血药浓度，减少严重急性GVHD的发生，改善移植疗效。

Guidelines for the Prevention and Management of Graft-versus-Host Disease after Cord Blood Transplantation

The incidence of graft-versus-host disease (GVHD) after cord blood (CB) transplantation (CBT) is lower than expected given the marked degree of human leukocyte antigen (HLA)-mismatch of CB grafts. While the exact mechanism that underlies this biology remains unclear, it is hypothesized to be due to the low number of mostly immature T-cells infused as part of the graft1,2, and increased tolerance of CB-derived lymphocytes induced by the state of pregnancy. Nevertheless, acute GVHD (aGVHD) is a significant complication of CBT. In contrast, the incidence of chronic GVHD (cGVHD) following CBT is lower than what is observed following matched related or unrelated donor HSC transplantation (HSCT)3-6. This review outlines the guidelines for the prevention and management of acute and chronic GVHD following CBT.

Effect of Early Post-Transplantation Tacrolimus Concentration on the Risk of Acute Graft-Versus-Host Disease in Allogenic Stem Cell Transplantation

Simple Summary

Allogeneic hematopoietic stem cell transplantation is a potentially curative treatment for many hematological malignancies and disorders but is often complicated by a relapse of the underlying disease, graft-vs-host disease and infectious complications. However, despite the introduction of calcineurin inhibitors such as tacrolimus, graft-versus-host disease remains one of the major life-threatening complications of allogeneic hematopoietic stem cell transplantation. Due to a variety of factors, there is variability in tacrolimus concentrations during the early weeks post-transplantation. Since the immunologic events leading to acute GVHD also occur in the first few days post-transplantation, it is important that optimal levels be attained early after transplantation. The findings from this study will help inform the management of optimal tacrolimus levels to be attained early post-transplantation.

Abstract

Acute graft versus host disease (aGVHD) remains a leading cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant (allo-HSCT). Tacrolimus (TAC), a calcineurin inhibitor that prevents T-cell activation, is commonly used as a GVHD prophylaxis. However, there is variability in the serum concentrations of TAC, and little is known on the impact of early TAC levels on aGVHD. We retrospectively analyzed 673 consecutive patients undergoing allo-HSCT at the Ohio State University between 2002 and 2016. Week 1 TAC was associated with a lower risk of aGVHD II–IV at TAC level ≥10.15 ng/mL (p = 0.03) compared to the lowest quartile. The cumulative incidence of relapse at 1, 3 and 5 years was 33%, 38% and 41%, respectively. TAC levels at week 2, ≥11.55 ng/mL, were associated with an increased risk of relapse (p = 0.01) compared to the lowest quartile. Subset analysis with acute myeloid leukemia and myelodysplastic syndrome patients showed significantly reduced aGVHD with TAC level ≥10.15 ng/mL at week 1 and a higher risk of relapse associated with week 2 TAC level ≥11.55 ng/mL (p = 0.02). Hence, achieving ≥10 ng/mL during the first week of HCT may mitigate the risk of aGVHD. However, levels (>11 ng/mL) beyond the first week may be associated with suppressed graft versus tumor effect and higher relapse.

Evaluation of the performance of a prior tacrolimus population pharmacokinetic kidney transplant model among adult allogeneic hematopoietic stem cell transplant patients

Abstract

Tacrolimus is a calcineurin inhibitor used to prevent acute graft versus host disease in adult patients receiving allogeneic hematopoietic stem cell transplantation (HCT). Previous population pharmacokinetic (PK) models have been developed in solid organ transplant, yet none exists for patients receiving HCT. The primary objectives of this study were to (1) use a previously published population PK model in adult patients who underwent kidney transplant and apply it to allogeneic HCT; (2) evaluate model‐predicted tacrolimus steady‐state trough concentrations and simulations in patients receiving HCT; and (3) evaluate covariates that affect tacrolimus PK in allogeneic HCT. A total of 252 adult patients receiving allogeneic HCT were included in the study. They received oral tacrolimus twice daily (0.03 mg/kg) starting 3 days prior to transplant. Data for these analyses included baseline clinical and demographic data, genotype data for single nucleotide polymorphisms in CYP3A4/5 and ABCB1, and the first tacrolimus steady‐state trough concentration. A dosing simulation strategy based on observed trough concentrations (rather than model‐based predictions) resulted in 12% more patients successfully achieving tacrolimus trough concentrations within the institutional target range (5–10 ng/ml). Stepwise covariate analyses identified HLA match and conditioning regimen (myeloablative vs. reduced intensity) as significant covariates. Ultimately, a previously published tacrolimus population PK model in kidney transplant provided a platform to help establish a model‐based dose adjustment strategy in patients receiving allogenic HCT, and identified HCT‐specific covariates to be considered for future prospective studies.

Evaluating risk factors for acute graft versus host disease in pediatric hematopoietic stem cell transplant patients receiving tacrolimus

To identify the clinical and pharmacological risk factors associated with tacrolimus pharmacodynamics for acute graft‐versus‐host disease (aGVHD) in pediatric patients receiving allogeneic hematopoietic stem cell transplantation (HSCT) from a matched related donor. A retrospective cohort single center chart review study was conducted with pediatric patients who received tacrolimus prophylaxis after allogeneic HSCT between January 1, 2017, and December 31, 2019. Potential risk factors were tested separately between aGVHD and non‐aGVHD cohorts and were further analyzed in a logistic regression model with backward elimination and a partial least squares discriminant analysis. Thirty‐three patient cases were included in our study and 52% (17/33) developed aGVHD while on tacrolimus prophylaxis. When tested independently, donor age and sibling versus parent donor/recipient relation were shown to be statistically significant between aGVHD and non‐aGVHD patients (p < 0.005). Pharmacological factors associated with tacrolimus treatment failed to demonstrate a significant impact on patient’s risk of aGVHD. Using a best fit logistic regression model that tested all the variables together, donor age was the only significant variable predicting patient’s risk of aGVHD (p < 0.01). Donor relationship and donor age were unable to be evaluated separately and are therefore confounding variables. Among pediatric patients receiving allogeneic HSCT, aGVHD risk is significantly decreased by either sibling donor and/or younger donors. Although no conclusions were drawn on the effect of tacrolimus therapy (p = 0.08), results warrant additional research with a larger sample size to evaluate the accuracy of monitoring tacrolimus serum trough levels.

Initial tacrolimus weight-based dosing strategy in allogeneic hematopoietic stem-cell transplantation

Tacrolimus is a mainstay medication for graft-versus-host disease (GVHD) prophylaxis in combination with other immunosuppressive agents. Achieving therapeutic tacrolimus levels is vital in preventing acute GVHD (aGVHD), while supratherapeutic levels may increase risk of toxicity and relapse. We performed a single center retrospective chart review including all adult patients post-allogeneic hematopoietic stem-cell transplantation who received initial tacrolimus continuous intravenous infusion for GVHD prophylaxis between June 1, 2017 and December 31, 2019. The primary outcome was the percent of patients with an initial therapeutic tacrolimus level, defined as 5-12 ng/mL, after empiric weight-based dosing at 0.02 mg/kg/day. Secondary outcomes included evidence of tacrolimus toxicity within seven days of initiation, incidence of aGVHD by day 100, and relapse after six months. An initial therapeutic level was achieved in 47% of patients with a median initial level of 12.4 ng/mL. Fifty-two percent of patients had supratherapeutic levels. No significant nephrotoxicity, hepatotoxicity, or neurotoxicity occurred within a week of starting tacrolimus or at neutrophil engraftment. Grade II-IV aGVHD by day 100 was observed in 22% of patients, and relapse after six months was found in 16% of patients. These results have led to consideration of an empiric 20% dose reduction to 0.016 mg/kg/day or an expanded initial tacrolimus target of 5-15 ng/mL as there was low aGVHD incidence and no increased risk of toxicity.

Intrapatient variability in concentration/dose ratio of tacrolimus predicts transplant-associated thrombotic microangiopathy

Tacrolimus (TAC) is essential for prophylaxis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic cell transplantation (allo-HSCT). We have sometimes observed large fluctuations in TAC concentration. However, links between the variability in the concentration or the concentration/dose (C/D) ratio of TAC and clinical complications remain ambiguous. To clarify relationships between various parameters of TAC and early complications such as pre-engraftment immune reactions/engraftment syndrome, aGVHD, and transplant-associated thrombotic microangiopathy (TA-TMA), a total of 146 patients who underwent allo-HSCT were included. Intrapatient variabilities in the concentration and C/D ratio of TAC were estimated by intrapatient mean absolute deviation (iMAD). The mean concentration and C/D ratio of TAC were not significantly different between with and without complications. A strong association was observed between greater iMAD for TAC C/D ratio from days 15 to 21 and the development of TA-TMA. iMAD values for TAC C/D ratio of 11.4 or greater was a risk factor for TA-TMA and the cumulative incidence of nonrelapse mortality (NRM) was significantly higher in patients with iMAD values for TAC C/D ratio of 11.4 or greater. Intrapatient variability in the C/D ratio of TAC was associated with the incidence of TA-TMA and NRM and might be useful for predicting TA-TMA.

The stability of initial tacrolimus concentration following allogeneic hematopoietic stem cell transplantation reduces the risk of acute GVHD

BACKGROUND

Early tacrolimus (TAC) concentrations correlate with the risk of acute graft-versus-host disease (aGVHD); however, whether the variability of early TAC concentrations after allo-HSCT governs the occurrence of aGVHD remains unknown. Here, we evaluate the correlation between the intrapatient variability (IPV) of initial TAC concentrations and the development of aGVHD.

METHODS

We retrospectively assessed 202 patients who underwent allo-HSCT and received standard GVHD prophylaxis by continuous intravenous (iv) infusion of TAC and iv methotrexate. IPV was calculated by using the % coefficient of variation in the initial 4 weeks.

RESULTS

With median follow-up duration of 20.7 months, 24 patients were diagnosed with grades II-IV aGVHD. Overall survival (OS) and relapse at 12 months after allo-HSCT were 70.6% (95% confidence interval [CI], 63.7%-76.4%) and 18.9% (95% CI, 13.0%-24.4%), respectively. When IPV was categorized into two groups (high: ≥9.5%; low: <9.5%), the cumulative incidence of grades II-IV aGVHD was greater in the IPV-high group at week 3 (odds ratio: 4.15; 95% CI, 1.37%-12.6%, P = .01). No significant differences were observed in OS and relapse between the two groups.

CONCLUSION

We concluded that adjusting early TAC concentration stable may reduce aGVHD after allo-HSCT without affecting the relapse rate.

Tacrolimus dose modification in patients receiving concomitant isavuconazole after hematopoietic stem cell transplantation

INTRODUCTION

Isavuconazole is increasingly being used for antifungal prophylaxis during stem cell transplantation. Isavuconazole is a moderate inhibitor of Cytochrome P4503A4, and tacrolimus levels are anticipated to be elevated when given concomitantly with isavuconazole. We developed and validated a dose-modified tacrolimus regimen to better achieve and maintain target tacrolimus levels.Methods: Allogeneic stem cell transplantation recipients who received concomitant tacrolimus and isavuconazole from September 2017 to September 2018 were included. Tacrolimus was adjusted to achieve a target range 8-12 ng/ml. Intravenous tacrolimus was first initiated at 0.02 mg/kg/day on day 1, and transitioned to oral therapy using a 2:1 conversion ratio (n = 48). Clinical observations showed high interpatient variability. The intravenous dose was then reduced to 0.017 mg/kg/day, and oral:intravenous conversion changed to 3.1:1 (n = 24).

RESULTS

Interpatient variability was high (lower in the 0.017 mg/kg/day group; P < 0.0217). Patients in the 0.017 mg/kg/day group required fewer dose changes (P < 0.023) and had fewer levels >15 ng/ml (P < 0.021). Median tacrolimus dose declined over time; 0.016, 0.012 and 0.011 on days 1, 7 and 10 for patients receiving 0.02 mg/kg/day and 0.017, 0.014 and 0.013 in the 0.017 mg/kg group. Day 10 tacrolimus accumulation factor was 1.42 R_ac(Cmax) in the 0.02 mg/kg/day cohort compared to 1.23 R_ac(Cmax) in the 0.017 mg/kg/day cohort (P < 0.015). When transitioned to oral therapy, a oral:intravenous conversion ratio >3.1:1 was shown to improve chances for achieving target levels (P > 0.0744).

CONCLUSION

We recommend initiating intravenous tacrolimus dose at 0.017 mg/kg/day and using a 3.1:1 oral:intravenous conversion to reduce interpatient variability, drug accumulation and the number of suboptimal tacrolimus levels. Tacrolimus requires frequent drug level monitoring.

Pharmacogenetics and tacrolimus administration in stem cell transplantation

Tacrolimus is the gold standard immunosuppressant administered in solid organ and stem cell transplantation to avoid graft rejection post-transplant. Despite its widespread use, there is a large variation in response to therapy, likely due to high inter-individual pharmacokinetic variability. Therapeutic drug monitoring is employed to improve clinical response and reduce toxicity. There is substantial evidence that pharmacogenetics influences drug exposure and response. CYP3A5 genotype significantly impacts oral tacrolimus concentrations and response after solid organ transplantation. There are fewer studies in stem cell transplantation and with intravenous tacrolimus dosing. This report highlights recent evidence suggesting genes such as CYP3A4 and ABCB1 play a larger role after intravenous dosing compared with CYP3A5, and the role for novel genes on tacrolimus outcomes.

Influence of Germline Genetics on Tacrolimus Pharmacokinetics and Pharmacodynamics in Allogeneic Hematopoietic Stem Cell Transplant Patients

Tacrolimus exhibits high inter-patient pharmacokinetics (PK) variability, as well as a narrow therapeutic index, and therefore requires therapeutic drug monitoring. Germline mutations in cytochrome P450 isoforms 4 and 5 genes (CYP3A4/5) and the ATP-binding cassette B1 gene (ABCB1) may contribute to interindividual tacrolimus PK variability, which may impact clinical outcomes among allogeneic hematopoietic stem cell transplantation (HSCT) patients. In this study, 252 adult patients who received tacrolimus for acute graft versus host disease (aGVHD) prophylaxis after allogeneic HSCT were genotyped to evaluate if germline genetic variants associated with tacrolimus PK and pharmacodynamic (PD) variability. Significant associations were detected between germline variants in CYP3A4/5 and ABCB1 and PK endpoints (e.g., median steady-state tacrolimus concentrations and time to goal tacrolimus concentration). However, significant associations were not observed between CYP3A4/5 or ABCB1 germline variants and PD endpoints (e.g., aGVHD and treatment-emergent nephrotoxicity). Decreased age and CYP3A5*1/*1 genotype were independently associated with subtherapeutic tacrolimus trough concentrations while CYP3A5*1*3 or CYP3A5*3/*3 genotypes, myeloablative allogeneic HSCT conditioning regimen (MAC) and increased weight were independently associated with supratherapeutic tacrolimus trough concentrations. Future lines of prospective research inquiry are warranted to use both germline genetic and clinical data to develop precision dosing tools that will optimize both tacrolimus dosing and clinical outcomes among adult HSCT patients.

Efficacy, Safety, and Practicality of Tacrolimus Monitoring after Bone Marrow Transplant: Assessment of a Change in Practice

BACKGROUND

Currently, there is no standardized approach to the frequency of monitoring tacrolimus levels in patients who have undergone hematopoietic stem cell transplant (HSCT). Previously, the practice at the study hospital was to monitor tacrolimus levels daily throughout a patient's admission. A recent institutional study suggested that measurement of tacrolimus level is more frequent than needed to achieve consistent time in the therapeutic range (TTR), particularly after the first 7 days. As a result, tacrolimus monitoring was changed to daily measurement for the initial week of therapy, followed by measurements on Monday, Wednesday, and Friday in subsequent weeks.

OBJECTIVE

To confirm the safety and efficacy of the recent practice change.

METHODS

This retrospective chart review of HSCT patients admitted to The Ottawa Hospital involved 68 patients in the pre-practice change group and 43 patients in the post-practice change group. Data on tacrolimus measurement were collected for up to 21 days after initiation of this medication. The proportion of TTR was compared between the 2 groups. Differences in the incidence and severity of renal dysfunction and the incidence of acute graft versus host disease (GVHD) were determined and described.

RESULTS

In the pre-practice change cohort, the median proportion of TTR for tacrolimus was 40.5% for days 1-7, 65.1% for days 8-14, and 78.9% for days 15-21, similar to the values for the post-practice change group (46.6% [p = 0.09], 62.9% [p = 0.93], and 70.0% [p = 0.22], respectively, for the same periods). The incidence of acute GVHD within 100 days after HSCT was 24% and 33% for the pre- and post-practice change cohorts, respectively. The incidence and severity of renal dysfunction were similar between the 2 groups.

CONCLUSION

The proportion of TTR for tacrolimus was not significantly affected by the recent practice change. Similarly, the incidence and severity of renal dysfunction and the incidence of acute GVHD did not appear to differ between the pre- and post-practice change groups.

Allo-HSCT recipients with invasive fungal disease and ongoing immunosuppression have a high risk for developing tuberculosis

Patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) are at high risk of acquiring tuberculosis (TB) due to a status of immunosuppression. We conducted a nested case control study to investigate the incidence and risk factors for TB after allo-HSCT. Between 2012 and 2017, 730 consecutive allo-HSCT recipients were enrolled, and 14 patients (1.92%) were diagnosed with TB. Relatively, 54 allo-HSCT recipients were selected as control. Patients who suffered TB had a significantly higher 3-year non-relapse mortality rate than the control group (30.36% vs 5.39%, P < 0.01). In multivariate analysis, invasive fungal disease (HR 4.87, 95% CI 1.39–17.09), treatment with a relatively high dose of prednisone (HR 10.34, 95% CI 1.12–95.47) and treatment with tacrolimus (HR 4.79, 95% CI 1.18–19.44) were identified independent risk factors for TB occurrence post allo-HSCT (P < 0.05). Meanwhile, donor type, dose and type of anti-thymocyte globulin (ATG) administrated, as well as treatment intensity, did not alter the incidence of TB. Therefore, allo-HSCT recipients with unexplained fever, especially those who suffer from invasive fungal disease and ongoing immunosuppression with a relatively high dose of prednisone or tacrolimus, are at a high-risk of developing active TB. Closely Monitoring TB occurrence, making a timely diagnosis and administering the proper treatment may be beneficial to those high-risk patients.

Tacrolimus in adult hematopoietic stem cell transplantation

Introduction: Graft-versus-host disease (GVHD) is the most common complication of hematopoietic stem cell transplantation (HSCT); therefore, the prevention of GVHD is important for a successful treatment. Tacrolimus (Tac), a calcineurin inhibitor, has been widely used for the prophylaxis of GVHD in HSCT recipients. Areas covered: This review introduces phase II/III of clinical trials related with Tac's roles in the prevention of GVHD in HSCT. Furthermore, we discuss the normal ranges of Tac concentrations, pharmacogenetics, and drug interactions of Tac, as well as its side effects in adult HSCT recipients. Expert opinion: A series of studies has established the efficacy and safety of Tac alone or in combination with other agents in HSCT. However, successful administration of Tac is complicated by its narrow therapeutic window, inter-patient pharmacokinetic variability, and a spectrum of undesirable side effects. It is necessary to maintain concentrations of Tac within the desired ranges for GVHD prophylaxis. Moreover, various factors contribute to significant variability in Tac pharmacokinetics, including drug interactions and genomic variation.

Phase I study of graft-versus-host disease prophylaxis including bortezomib for allogeneic hematopoietic cell transplantation from unrelated donors with one or two HLA loci mismatches in Japanese patients

This phase I study was designed for graft-versus-host disease (GVHD) prophylaxis including bortezomib in allogeneic hematopoietic cell transplantation (allo-HCT) from human leukocyte antigen (HLA)-mismatched unrelated donors in Japanese patients. Patients were administered bortezomib on days 1, 4, and 7, with short-term methotrexate and tacrolimus. Three bortezomib dose levels were prepared (1.0, 1.3, and 1.5 mg/m²). A dose of 1.3 mg/m² was planned for administration to the initial six patients, and was adjusted if dose-limiting toxicity developed. Five of six patients enrolled for the initial dose had bone marrow donors. Two cases had single-antigen and single-allele mismatches; four had single-antigen mismatch at the A, B, C, and/or DRB1 loci in the GVH direction. All patients achieved neutrophil engraftment and complete donor chimerism. Three patients developed grade II acute GVHD, and none developed grade III-IV GVHD or any dose-limiting toxicity attributable to bortezomib by day 100. Two patients developed late-onset acute GVHD, and two developed chronic GVHD, but all cases were manageable. All patients were alive without relapse after a median follow-up period of 52 months. The optimal dose of bortezomib was determined to be 1.3 mg/m². Prophylaxis against GVHD using a regimen including bortezomib thus seems feasible for HLA-mismatched unrelated allo-HCT.

Tacrolimus Levels in the Prophylaxis of Acute Graft-Versus-Host Disease in the Chinese Early After Hematopoietic Stem Cell Transplantation

BACKGROUND

Tacrolimus has been widely accepted as the backbone of acute graft-versus-host disease (aGVHD) prophylaxis in allogeneic hematopoietic stem cell transplantation (alloHSCT). The present work evaluated whether tacrolimus concentrations early after transplant correlate with the incidence of aGVHD in Chinese alloHSCT recipients.

METHODS

One hundred four Chinese alloHSCT recipients were included in this retrospective study. All patients received standard prophylaxis with tacrolimus and short-term methotrexate. Blood samples were taken at steady-state for those on i.v. tacrolimus (Cv) or predose (C0) and 2 hours after the last oral dose (C2).

RESULTS

In the first 8 weeks after alloHSCT, significant variability in Cv, C0, and C2 of Chinese patients was observed. It was found that higher tacrolimus C0 and C2 values tended to be associated with a reduced risk of aGVHD, although this was a nonsignificant trend due to the small sample size involved. Receiver operating characteristic curve analysis indicated that Cv levels of ≥16.52 ng/mL, C0 levels of ≥5.56 ng/mL, and C2 levels of ≥7.83 ng/mL minimized the incidence of treatment failure during weeks 3-4 with intravenous administration and weeks 5-6 with oral administration. There was no statistically significant association of the patient liver and kidney function with the blood concentration of tacrolimus in the desired range of 5-20 ng/mL.

CONCLUSIONS

Tacrolimus therapeutic drug monitoring improved treatment outcomes of Chinese alloHSCT recipients. Cv measurements during weeks 3-4 and C0 or C2 measurements during weeks 5-6 better predicted aGVHD (I-IV) than the concentrations measured at other time points during the first 6 weeks after alloHSCT.

Cyclosporine A trough concentrations are associated with acute GvHD after non-myeloablative allogeneic hematopoietic cell transplantation

Low plasma CsA concentrations (<300–350 ng/mL) early following allogeneic hematopoietic stem cell transplantation (HSCT) is associated with an increased risk of developing acute graft-versus-host disease (aGvHD). Nevertheless, the current optimal target trough concentration for CsA following HSCT is considered to be 200–400 ng/mL. Here, we performed a retrospective analysis of a homogeneous group of 129 patients who received HSCT after non-myeloablative conditioning, and we analyzed the impact of CsA trough concentration measured during the first four weeks (CsA W1-4) on the incidence aGvHD, relapse-free survival (RFS), non-relapse mortality (NRM), overall survival (OS), and toxicity. The 180-day incidence of grade II-IV aGvHD was 25% (32/129 patients). In multivariate analysis the incidence of grade II-IV aGvHD was significantly lower among patients with a CsA W1-4 concentration ≥350 ng/mL compared to patients with a concentration <350 ng/mL (18% versus 38%, respectively; P = 0.007), with a hazard ration (HR) of 0.38 (95% CI: 0.19–0.77). In contrast, we found no correlation between CsA trough concentration and RFS, NRM, or OS. Moreover, we found an increased incidence of hypomagnesemia at higher CsA concentrations, but no difference in the incidence of acute renal toxicity, hepatic toxicity, or electrolyte imbalance. Interestingly, 30% of patients experienced hyponatremia with no apparent cause other than the use of CsA, with urinalysis suggesting SIADH as the underlying cause. Our findings suggest that a CsA trough concentration of 350–500 ng/mL might be more appropriate in the first month following non-myeloablative HSCT.

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.

Upper gastrointestinal acute graft-versus-host disease adds minimal prognostic value in isolation or with other graft-versus-host disease symptoms as currently diagnosed and treated

Upper gastrointestinal acute graft-versus-host disease is reported in approximately 30% of hematopoietic stem cell transplant recipients developing acute graft-versus-host disease. Currently classified as Grade II in consensus criteria, upper gastrointestinal acute graft-versus-host disease is often treated with systemic immunosuppression. We reviewed the Center for International Blood and Marrow Transplant Research database to assess the prognostic implications of upper gastrointestinal acute graft-versus-host disease in isolation or with other acute graft-versus-host disease manifestations. 8567 adult recipients of myeloablative allogeneic hematopoietic stem cell transplant receiving T-cell replete grafts for acute leukemia, chronic myeloid leukemia or myelodysplastic syndrome between 2000 and 2012 were analyzed. 51% of transplants were from unrelated donors. Reported upper gastrointestinal acute graft-versus-host disease incidence was 12.1%; 2.7% of recipients had isolated upper gastrointestinal acute graft-versus-host disease, of whom 95% received systemic steroids. Patients with isolated upper gastrointestinal involvement had similar survival, disease-free survival, transplant-related mortality, and relapse as patients with Grades 0, I, or II acute graft-versus-host disease. Unrelated donor recipients with isolated upper gastrointestinal acute graft-versus-host disease had less subsequent chronic graft-versus-host disease than those with Grades I or II disease (P=0.016 and P=0.0004, respectively). Upper gastrointestinal involvement added no significant prognostic information when present in addition to other manifestations of Grades I or II acute graft-versus-host disease. If upper gastrointestinal symptoms were reclassified as Grade 0 or I, 425 of 2083 patients (20.4%) with Grade II disease would be downgraded, potentially impacting the interpretation of clinical trial outcomes. Defining upper gastrointestinal acute graft-versus-host disease as a Grade II entity, as it is currently diagnosed and treated, is not strongly supported by this analysis. The general approach to diagnosis, treatment and grading of upper gastrointestinal symptoms and their impact on subsequent acute graft-versus-host disease therapy warrants reevaluation.

Higher Peak Tacrolimus Concentrations after Allogeneic Hematopoietic Stem Cell Transplantation Increase the Risk of Endothelial Cell Damage Complications

Noninfectious transplantation-related complications (TRCs) such as graft-versus-host disease (GVHD) and endothelial cell damage (TRC-EC) are critical after allogeneic hematopoietic stem cell transplantation. Tacrolimus (TAC) is used to control GVHD. Hypertension and renal failure are common adverse events after TAC treatment. Higher blood concentrations of TAC would be expected to reduce the risk of GVHD but may increase TRC-EC. TRC-EC often develops in patients with GVHD; thus, it is difficult to clinically determine the proper intensity of immunosuppression. We therefore evaluated the impact of weekly mean/peak TAC blood concentrations (PTCs) on TRC-EC occurrence and prognosis. Patients (N = 295) who received TAC as a GVHD prophylaxis at our institute from 2009 to 2016 were eligible for this retrospective study. Forty-three patients were diagnosed with TRC-EC: 8 with sinusoidal obstructive syndrome, 28 with transplant-associated microangiopathy, and 7 with idiopathic pneumonia syndrome. The cumulative incidence of TRC-EC at 12 months was 13.8% (95% confidence interval [CI] 10.1% to 18.1%). After multivariate analysis high PTCs during days 22 to 28 (hazard ratio [HR] 2.47; 95% CI, 1.37 to 4.45; P < .01) and grades II to IV acute GVHD (HR, 5.61; 95% CI, 2.99 to 10.53; P < .01) were associated with TRC-EC occurrence. The probability of overall survival (OS) at 12 months was 67.7% (95% CI, 61.7% to 73.0%). After multivariate analysis TRC-EC diagnosis (HR, 2.47, 95% CI, 1.59 to 3.83; P < .01) and high-risk disease (HR, 1.75; 95% CI, 1.17 to 2.61; P < .01) were significantly associated with poor OS. In conclusion, higher PTC during days 22 to 28 increased the risk of TRC-EC. TRC-EC development was associated with poor OS.

Graft-versus-host Disease-free, Relapse-free Survival After HLA-identical Sibling Peripheral Blood Stem Cell Transplantation With Tacrolimus-based Graft-versus-host Disease Prophylaxis in Japanese Patients

The ideal post-allogeneic hematopoietic cell transplantation recovery is not just the cure of hematologic malignancies but also freedom from ongoing morbidity. Recent studies have revealed that HLA-identical sibling peripheral blood stem cell transplantation (PBSCT) had been providing impaired graft-versus-host disease (GVHD)-free relapse-free survival (GRFS) due to a higher risk of GVHD. Study on GVHD prophylaxis bears clinical reliance when focused on Japanese population because risk of GVHD differs among races. We identified 15 consecutive Japanese patients who received tacrolimus-based GVHD prophylaxis after myeloablative HLA-identical sibling PBSCT. No episode of grade ≥ II acute GVHD and only one episode of grade III toxicity were documented, with the control of mean weekly blood tacrolimus concentrations during the first 4 weeks at 13 to 17 ng/mL. An estimated 46.7% (95% CI: 21.4% to 71.9%) of the patients enjoyed their GRFS at 3 years after transplantation, and failure in the treatment of chronic GVHD was not reported during the median follow-up period of 1059 days (range, 784 to 1778 days) after the development of chronic GVHD. The results suggest that the application of tacrolimus with the optimization of its blood concentrations may effectively prevent ongoing morbidities after HLA-identical sibling PBSCT.

The Hematopoietic Cell Transplant Pharmacist: Roles, Responsibilities, and Recommendations from the ASBMT Pharmacy Special Interest Group

Pharmacists are increasingly recognized as an essential member of the multidisciplinary team for hematopoietic cell transplant (HCT) patients. However, until recently, their educational background, required training, and potential roles have not been well described. Therefore, the purpose of this manuscript is to provide supporting evidence for the HCT Clinical Pharmacist Role Description, which has been endorsed by several organizations including the American Society for Blood and Marrow Transplantation. This document provides justification for the various roles pharmacists fulfill with respect to medication management, transitions of care, patient and provider education, policy development, quality improvement, and research. Furthermore, evidence supporting the value, financially and otherwise, HCT pharmacists provide is reviewed. Pharmacists in the HCT setting are encouraged to report on novel practice models and potential impact of their services to increase awareness and utilization of HCT pharmacists.

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.