Drug-interactions of azole antifungals with selected immunosuppressants in transplant patients: strategies for optimal management in clinical practice

Antifungal prophylaxis against invasive Candida and Aspergillus infection in adult heart transplant recipients: protocol for a systematic review and meta-analysis

INTRODUCTION

Invasive fungal infections (IFI) can contribute to increased mortality and morbidity rates after heart transplant in adults. The most common causes are Aspergillus and Candida species. There is uncertainty on how effective antifungal prophylaxis is against Candida spp infections and limited guidance on the prevention of Aspergillus spp infections. This systematic review and meta-analysis will assess the literature to see if antifungal prophylaxis reduces the incidence of IFI after heart transplant in adults.

METHODS AND ANALYSIS

This systematic review protocol follows the Preferred Reporting Items for Systematic reviews and Meta Analysis guidelines. A systematic search of the Cochrane Library, Web of Science, Scopus, Embase, MEDLINE, and Proquest databases will be undertaken. Reference lists of retrieved publications and conference abstracts will also be searched. Title, abstract and full-text screening will be undertaken by two reviewers. Discrepancies will be resolved by a third reviewer. Studies with paediatric patients, multi-organ transplants, or patients with a second heart transplant will be excluded, along with those who do not have clear definitions and diagnostic criteria for IFI. Risk of bias will be assessed using the Cochrane Risk of Bias 2 tool and the Risk of Bias in Non-randomised Studies of Interventions tool. A meta-analysis will be carried out, but if studies are not deemed to be sufficiently similar, only a narrative synthesis will be undertaken.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review as primary data will not be collected. The results of the review will be disseminated through publication in an academic journal and scientific conferences.

PROSPERO REGISTRATION NUMBER

CRD42024516588.

The impact of antimicrobial use on potential major drug-drug interactions in the pediatric Intensive Care Unit patients at University Hospital in Türkiye

BACKGROUND

Antimicrobials, especially antibiotics, are among the most widely used drugs in the pediatric intensive care unit. Pediatrics patients in intensive care unit are exposed to potential drug-drug interactions (PDDIs) and suffered from their adverse and side effects. The aim of this study is to evaluate the impact of antimicrobial use on PDDIs, as well as to examine the rate and the risk factors PDDIs, furthermore the management of PDDIs.

METHODS

The present retrospective cohort study included 179 patients under 18 years of age who were hospitalized in Pediatric Intensive Care Unit in Türkiye. Drug interactions were evaluated using the Lexicomp® (Macedonia, OH, USA) drug interaction tool which provides evidence-based drug information.

RESULTS

Our study results showed that the frequency of the use of antimicrobial drugs (antibiotic, antifungal, antiviral) was found to be statistically significantly higher (P<0.05) in the group with PDDIs compared to the group without PDDIs. Especially, the use of carbapenem, cephalosporin among the antibiotic groups significantly increased the frequency of PDDIs (P<0.05). While the probability PDDIs statistically significantly increased 3.73 times (OR [odds ratio] = 3.73; 95% CI=1.47-9.50) in patients who used a single antibiotic compared to patients who did not use antibiotics (P=0.006), the probability of the occurrence of PDDIs by using more than one antibiotic was statistically significantly 8.5 times (95% CI=3.30-21.89) (P<0.001).

CONCLUSIONS

Our study results showed that the use of antimicrobial drugs (antibiotic, antifungal, antiviral) was found to be statistically significantly higher (P<0.05) in the group with PDDIs.

Clinical treatment of cryptococcal meningitis: an evidence-based review on the emerging clinical data

Cryptococcal meningitis (CM) is a fatal fungal central nervous system (CNS) infection caused by Cryptococcus infecting the meninges and/or brain parenchyma, with fever, headache, neck stiffness, and visual disturbances as the primary clinical manifestations. Immunocompromised individuals with human immunodeficiency virus (HIV) infection or who have undergone organ transplantation, as well as immunocompetent people can both be susceptible to CM. Without treatment, patients with CM may have a mortality rate of up to 100% after hospital admission. Even after receiving therapy, CM patients may still suffer from problems such as difficulty to cure, poor prognosis, and high mortality. Therefore, timely and effective treatment is essential to improve the mortality and prognosis of CM patients. Currently, the clinical outcomes of CM are frequently unsatisfactory due to limited drug choices, severe adverse reactions, drug resistance, etc. Here, we review the research progress of CM treatment strategies and discuss the suitable options for managing CM, hoping to provide a reference for physicians to select the most appropriate treatment regimens for CM patients.

An update on drug-drug interactions for care of the acutely ill in the era of COVID-19

PURPOSE

To provide key pharmacological concepts underlying drug-drug interactions (DDIs), a decision-making framework, and a list of DDIs that should be considered in the context of contemporary acutely ill patients with COVID-19.

SUMMARY

DDIs are frequently encountered in the acutely ill. The implications of DDIs include either increased risk of drug toxicity or decreased effectiveness, which may have severe consequences in the acutely ill due to lower physiological and neurocognitive reserves in these patients. In addition, an array of additional therapies and drug classes have been used for COVID-19 that were not typically used in the acute care setting. In this update on DDIs in the acutely ill, we provide key pharmacological concepts underlying DDIs, including a discussion of the gastric environment, the cytochrome P-450 (CYP) isozyme system, transporters, and pharmacodynamics in relation to DDIs. We also provide a decision-making framework that elucidates the identification of DDIs, risk assessment, selection of alternative therapies, and monitoring. Finally, important DDIs pertaining to contemporary acute care clinical practice related to COVID-19 are discussed.

CONCLUSION

Interpreting and managing DDIs should follow a pharmacologically based approach and a systematic decision-making process to optimize patient outcomes.

Population pharmacokinetic analyses of tacrolimus in non-transplant patients: a systematic review

BACKGROUND AND OBJECTIVES

Tacrolimus (TAC) has been increasingly used in patients with non-transplant settings. Because of its large between-subject variability, several population pharmacokinetic (PPK) studies have been performed to facilitate individualized therapy. This review summarized published PPK models of TAC in non-transplant patients, aiming to clarify factors affecting PKs of TAC and identify the knowledge gap that may require further research.

METHODS

The PubMed, Embase databases, and Cochrane Library, as well as related references, were searched from the time of inception of the databases to February 2023, to identify TAC population pharmacokinetic studies modeled in non-transplant patients using a non-linear mixed-effects modeling approach.

RESULTS

Sixteen studies, all from Asian countries (China and Korea), were included in this study. Of these studies, eleven and four were carried out in pediatric and adult patients, respectively. One-compartment models were the commonly used structural models for TAC. The apparent clearance (CL/F) of TAC ranged from 2.05 to 30.9 L·h^-1 (median of 14.9 L·h^-1). Coadministered medication, genetic factors, and weight were the most common covariates affecting TAC-CL/F, and variability in the apparent volume of distribution (V/F) was largely explained by weight. Coadministration with Wuzhi capsules reduced CL/F by about 19 to 43%. For patients with CYP3A5*1*1 and *1*3 genotypes, the CL/F was 39-149% higher CL/F than patients with CYP3A5*1*1.

CONCLUSION

The optimal TAC dosage should be adjusted based on the patient's co-administration, body weight, and genetic information (especially CYP3A5 genotype). Further studies are needed to assess the generalizability of the published models to other ethnic groups. Moreover, external validation should be frequently performed to improve the clinical practicality of the models.

Antifungal prophylaxis with nebulized amphotericin-B in solid-organ transplant recipients with severe COVID-19: a retrospective observational study

COVID-19-associated pulmonary aspergillosis (CAPA) has emerged as a frequent complication in the intensive care unit (ICU). However, little is known about this life-threatening fungal superinfection in solid organ transplant recipients (SOTRs), including whether targeted anti-mold prophylaxis might be justified in this immunosuppressed population. We performed a multicentric observational retrospective study of all consecutive ICU-admitted COVID-19 SOTRs between August 1, 2020 and December 31, 2021. SOTRs receiving antifungal prophylaxis with nebulized amphotericin-B were compared with those without prophylaxis. CAPA was defined according the ECMM/ISHAM criteria. Sixty-four SOTRs were admitted to ICU for COVID-19 during the study period. One patient received antifungal prophylaxis with isavuconazole and was excluded from the analysis. Of the remaining 63 SOTRs, nineteen (30.2%) received anti-mold prophylaxis with nebulized amphotericin-B. Ten SOTRs who did not receive prophylaxis developed pulmonary mold infections (nine CAPA and one mucormycosis) compared with one who received nebulized amphotericin-B (22.7% vs 5.3%; risk ratio 0.23; 95%CI 0.032-1.68), but with no differences in survival. No severe adverse events related to nebulized amphotericin-B were recorded. SOTRs admitted to ICU with COVID-19 are at high risk for CAPA. However, nebulized amphotericin-B is safe and might reduce the incidence of CAPA in this high-risk population. A randomized clinical trial to confirm these findings is warranted.

Prospective Prediction of Dapaconazole Clinical Drug-Drug Interactions Using an In Vitro to In Vivo Extrapolation Equation and PBPK Modeling

This study predicted dapaconazole clinical drug−drug interactions (DDIs) over the main Cytochrome P450 (CYP) isoenzymes using static (in vitro to in vivo extrapolation equation, IVIVE) and dynamic (PBPK model) approaches. The in vitro inhibition of main CYP450 isoenzymes by dapaconazole in a human liver microsome incubation medium was evaluated. A dapaconazole PBPK model (Simcyp version 20) in dogs was developed and qualified using observed data and was scaled up for humans. Static and dynamic models to predict DDIs following current FDA guidelines were applied. The in vitro dapaconazole inhibition was observed for all isoforms investigated, including CYP1A2 (IC50 of 3.68 µM), CYP2A6 (20.7 µM), 2C8 (104.1 µM), 2C9 (0.22 µM), 2C19 (0.05 µM), 2D6 (0.87 µM), and 3A4 (0.008−0.03 µM). The dynamic (PBPK) and static DDI mechanistic model-based analyses suggest that dapaconazole is a weak inhibitor (AUCR > 1.25 and <2) of CYP1A2 and CYP2C9, a moderate inhibitor (AUCR > 2 and <5) of CYP2C8 and CYP2D6, and a strong inhibitor (AUCR ≥ 5) of CYP2C19 and CYP3A, considering a clinical scenario. The results presented may be a useful guide for future in vivo and clinical dapaconazole studies.

Effect of posaconazole on the concentration of intravenous and oral cyclosporine in patients undergoing hematopoietic stem cell transplantation

PURPOSE

This study aimed to investigate the interactions between posaconazole (POS) and intravenously/orally administered cyclosporine A (CsA) in allogeneic hematopoietic stem cell transplant (HSCT) recipients.

METHODS

We included 118 allogeneic HSCT patients who received CsA and POS simultaneously between January 2017 and June 2020 in this study. The ratio of CsA blood concentration (ng/mL) to dosage (mg/day) (C/D) before and after POS initiation was compared.

RESULTS

After the initiation of POS, the level of CsA increased 1 to 2 times in 66% (78/118) of patients compared to those without POS. However, the CsA C/D ratio increased by more than threefold in 6% (7/118) of patients after POS initiation, with an increase of more than fourfold in two patients. The median C/D ratio of CsA increased from 0.89 to 1.23 (P < 0.001) and 0.78 to 1.22 (P < 0.001) after POS initiation when CsA was administered intravenously and orally, respectively. In patients who received POS at the time of transition from intravenous to oral CsA, the value increased from 1.01 to 1.38 (P = 0.001). The route of administration had no significant effect on the change in the CsA C/D ratio (P = 0.615). Additionally, we observed the time required for the C/D ratio to reach a plateau after POS initiation was similar on days 13, 8, and 15 under various scenarios.

CONCLUSION

POS treatment increased blood CsA levels. A large variability was found in the fold-change in the CsA C/D ratio. Therefore, CsA doses should be adjusted by closely monitoring the blood levels of CsA after POS initiation.

Real clinical impact of drug-drug interactions of immunosuppressants in transplant patients

The main objective was to determine the prevalence of real drug-drug interactions (DDIs) of immunosuppressants in transplant patients. We conducted a prospective, observational 1-year study at a tertiary hospital, including all transplanted patients. We evaluated data from monitoring blood concentrations of immunosuppressive drugs and adverse drug events (ADEs) caused by DDIs. The DDIs were classified as C, D, or X according to their Lexi-Interact rating (C = monitor therapy, D = consider therapy modification, X = avoid combination). The clinical importance of real DDIs was expressed in terms of patient outcomes. The causality of DDIs was determined using Drug Interaction Probability Scale. The data were analyzed using Statistical Package for Social Sciences v. 25.0. A total of 309 transplant patients were included. Their mean age was 52.0 ± 14.7 years (18-79) and 69.9% were male. The prevalence of real DDIs was 21.7%. Immunosuppressive drugs administered with antifungal azoles and tacrolimus (TAC) with nifedipine have a great clinical impact. Real DDIs caused ADEs in 22 patients. The most common clinical outcome was nephrotoxicity (1.6%; n = 5), followed by hypertension (1.3%; n = 4). Suggestions for avoiding category D and X DDIs included: changing the immunosuppressant dosage, using paracetamol instead of non-steroidal anti-inflammatory drugs, and interrupting atorvastatin. The number of drugs prescribed and having been prescribed TAC was associated with an increased risk of real DDIs. There are many potential DDIs described in the literature but only a small percentage proved to be real DDIs, based on the patients´ outcomes.

Effects and safety evaluation of Wuzhi Capsules combined with tacrolimus for the treatment of kidney transplantation recipients

WHAT IS KNOWN AND OBJECTIVE

Tacrolimus (FK506), an effective and potent calcineurin inhibitor, is the cornerstone of immunosuppression after kidney transplantation. Wuzhi capsule (WZC), a prescribed ethanol extract of Nan-Wuweizi (Schisandra sphenanthera), is widely prescribed for kidney transplant recipients for the maintenance of tacrolimus concentration in clinical settings. Previous studies have demonstrated that WZC can increase the blood concentration of tacrolimus. However, it remains controversial whether to use WZC can be used to increase tacrolimus concentration in clinical practice. Our study aimed to evaluate the efficacy and safety of WZC combined with tacrolimus in the treatment of kidney transplant recipients.

METHODS

One hundred and ninety four Chinese kidney transplant recipients were included in this retrospective study. The recipients were divided into two groups (non-WZC group and WZC group). We investigated the effects of WZC on tacrolimus in terms of tacrolimus metabolism, laboratory tests, pharmacogenomics, renal function and adverse reactions.

RESULTS AND DISCUSSION

The concentration/dose (C₀ /D) of tacrolimus was significantly higher in the WZC group than the non-WZC group. The laboratory findings of blood routine tests, liver and kidney function were not significantly different between the two groups. The CYP3A5 genotype showed clearly associated with tacrolimus C₀ /D, whereas no significant difference was observed in patients with CYP3A4*1B, CYP3A4*22, ABCB1, ABCC2, POR*28 or PXR alleles. The improvement of C₀ /D by administration of WZC was significant in CYP3A5 expressers compared to non-expressers. Furthermore, the WZC group had a remarkably higher proportion of subjects who reached the target tacrolimus concentration than the non-WZC group. No significant differences in renal function and adverse reactions were observed between the groups.

WHAT IS NEW AND CONCLUSION

Wuzhi capsule can increase tacrolimus concentration without negative effects on renal function and adverse reactions, especially in CYP3A5 expressers. Efficient and economical synergistic effects can be achieved by the combined administration of WZC in kidney transplant recipients.

Dose tailoring of tacrolimus based on a non-linear pharmacokinetic model in children with refractory nephrotic syndrome

The population pharmacokinetics (PPK) of tacrolimus (TAC) in children with refractory nephrotic syndrome (RNS) have not been well-characterized. This study aimed to investigate the significant factors affecting the TAC PPK characteristics of children with RNS and to optimize the dosing regimen. A total of 494 concentrations from 108 children were obtained from routine therapeutic drug monitoring between 2016 and 2018. Information regarding the demographic features, laboratory test results, genetic polymorphisms of CYP3A5 (rs776746) and co-therapy medications were collected. PPK analysis was performed using the nonlinear mixed-effects modelling (NONMEM) software and two modelling strategies (the linear one-compartment model and nonlinear Michaelis-Menten model) were evaluated and compared. CYP3A5 genotype, weight, daily dose of TAC and daily dose of diltiazem were retained in the final linear model. The absorption rate constant (Ka) was set at 4.48 h^-1 in the linear model, and the apparent clearance (CL/F) and volume of distribution (V/F) in the final linear model were 14.2 L/h and 172 L, respectively. CYP3A5 genotype, weight and daily dose of diltiazem were the significant factors retained in the final nonlinear model. The maximal dose rate (V_max) and the average steady-state concentration at half-Vmax (K_m) in the final nonlinear model were 2.15 mg/day and 0.845 ng/ml, respectively. The nonlinear model described the pharmacokinetic data of TAC better than the linear model in children with RNS. A dosing regimen was proposed based on weight, CYP3A5 genotype and daily dose of diltiazem according to the final nonlinear PK model, which may facilitate individualized drug therapy with TAC.

Acute death caused by invasive aspergillosis after living-donor liver transplantation despite good graft function: a case report

Background

Invasive aspergillosis (IA) is one of the most serious causes of death after liver transplantation (LT). IA is the second most common fungal infection, and its mortality rate exceeds 80%.

Case presentation

A 67-year-old man presented to our hospital because of fulminant hepatitis caused by hepatitis B virus. Candidiasis was detected in his sputum, and micafungin had already been administered. Living-donor LT was performed using a right lobe graft donated from his daughter with no intraoperative complications. Although he appeared to have good graft function, his oxygenation was inadequate, and a chest radiograph showed many invasive shadows on postoperative day 1. A computed tomography scan also showed many invasive shadows with the halo sign. A blood examination revealed positivity for Aspergillus antigen, and Aspergillus species were detected in his sputum. IA was diagnosed. The antifungal therapy was soon modified to amphotericin B combined with caspofungin. Despite good graft blood flow through the portal vein and hepatic artery and good graft function, the patient died of IA on postoperative day 3. The median time from LT to IA among reports published to date ranges from 18 to 25 days.

Conclusions

The present report describes the first case of very early onset of IA after LT.

Invasive aspergillosis in solid organ transplant patients: diagnosis, prophylaxis, treatment, and assessment of response

BACKGROUND

Invasive aspergillosis (IA) is a rare complication in solid organ transplant (SOT) recipients. Although IA has significant implications on graft and patient survival, data on diagnosis and management of this infection in SOT recipients are still limited.

METHODS

Discussion of current practices and limitations in the diagnosis, prophylaxis, and treatment of IA and proposal of means of assessing treatment response in SOT recipients.

RESULTS

Liver, lung, heart or kidney transplant recipients have common as well as different risk factors to the development of IA, thus each category needs a separate evaluation. Diagnosis of IA in SOT recipients requires a high degree of awareness, because established diagnostic tools may not provide the same sensitivity and specificity observed in the neutropenic population. IA treatment relies primarily on mold-active triazoles, but potential interactions with immunosuppressants and other concomitant therapies need special attention.

CONCLUSIONS

Criteria to assess response have not been sufficiently evaluated in the SOT population and CT lesion dynamics, and serologic markers may be influenced by the underlying disease and type and severity of immunosuppression. There is a need for well-orchestrated efforts to study IA diagnosis and management in SOT recipients and to develop comprehensive guidelines for this population.

Risk factors for the development of invasive aspergillosis after kidney transplantation: Systematic review and meta-analysis

To investigate risk factors for invasive aspergillosis (IA) after kidney transplantation (KT), we conducted a systematic search in PubMed and EMBASE to identify studies published until June 2020. We included case-control or cohort design studies comprising KT recipients with a diagnosis of IA, defined according to the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group criteria, and assessed risk factors for the development of IA. Random-effect models meta-analysis served to pool data. We identified eleven case-control studies (319 IA cases and 835 controls). There was an increased risk of IA among recipients with underlying chronic lung diseases (odds ratio [OR] = 7.26; 95% confidence interval [CI] = 1.05-50.06) and among those with diabetic nephropathy (OR = 1.65; 95% CI = 1.10-2.48). Requiring posttransplant hemodialysis (OR = 3.69; 95% CI = 2.13-6.37) or surgical reintervention (OR = 6.28; 95% CI = 1.67-23.66) were also associated with an increased risk. Moreover, a positive link was identified between IA and posttransplant bacterial infection (OR = 7.51; 95% CI = 4.37-12.91), respiratory tract viral infection (OR = 7.75; 95% CI = 1.60-37.57), cytomegalovirus infection or disease (OR = 2.67; 95% CI = 1.12-6.32), and acute graft rejection (OR = 3.01; 95% CI = 1.78-5.09). In contrast, receiving a kidney from a living donor was associated with a reduced risk (OR = 0.65; 95% CI = 0.46-0.93). KT recipients that accumulate several of these conditions should be closely monitored and a low threshold of suspicion for IA should be maintained. Future studies should explore the benefit of mold-active prophylaxis to this subgroup of KT recipients at highest risk.

Effects of antifungal drugs on the plasma concentrations and dosage of tacrolimus in kidney transplant patients

OBJECTIVES

Tacrolimus is one of the three basic immunosuppressants used following kidney transplantation, and its plasma concentration is susceptible to antifungal drugs. Abnormal tacrolimus concentrations may lead to adverse outcomes for patients. Adjustment of the tacrolimus dose after administering antifungal drugs to patients with fungal infection after transplantations therefore has important clinical significance. Our objective is to measure the impact of antifungal drugs on the plasma concentration of tacrolimus in kidney transplant patients.

METHODS

A retrospective study was carried out in 109 kidney transplant recipients treated with a tacrolimus-based regimen and antifungal drugs simultaneously. Tacrolimus levels and dosage requirements were compared before and during antifungal therapy.

RESULTS

The plasma levels of tacrolimus were significantly increased after the combination with voriconazole and fluconazole (p<0.05). Consequently, the daily dose of tacrolimus was significantly reduced after the combination (p<0.05). However, although the tacrolimus concentration was significantly decreased after the administration of caspofungin (p<0.05), no apparent change in the daily dose of tacrolimus was found. Moreover, there were no significant changes in the tacrolimus levels and the daily dose after the combination with micafungin (p>0.05).

CONCLUSIONS

Our results suggest that there is considerable variability in the interaction between tacrolimus and different antifungal drugs. The dose of tacrolimus should be reduced by two-thirds and one-third before the combination with voriconazole and fluconazole, respectively. It is not recommended that the dose should be adjusted before combination with other antifungal drugs, and the dose should be adjusted under the guidance of therapeutic drug monitoring.

Flucloxacillin decreases tacrolimus blood trough levels: a single-center retrospective cohort study

Purpose

Tacrolimus and everolimus are widely used to prevent allograft rejection. Both are metabolized by the hepatic cytochrome P450 (CYP) enzyme CYP3A4 and are substrate for P-glycoprotein (P-gp). Drugs influencing the activity or expression of CYP enzymes and P-gp can cause clinically relevant changes in the metabolism of immunosuppressants. Several case reports have reported that flucloxacillin appeared to decrease levels of drugs metabolized by CYP3A4 and P-gp. The magnitude of this decrease has not been reported yet.

Methods

In this single-center retrospective cohort study, we compared the tacrolimus and everolimus blood trough levels (corrected for the dose) before, during, and after flucloxacillin treatment in eleven transplant patients (tacrolimus n = 11 patients, everolimus n = 1 patient, flucloxacillin n = 11 patients).

Results

The median tacrolimus blood trough level decreased by 37.5% (interquartile range, IQR 26.4–49.7%) during flucloxacillin treatment. After discontinuation of flucloxacillin, the tacrolimus blood trough levels increased by a median of 33.7% (IQR 22.5–51.4%). A Wilcoxon signed-rank test showed statistically significantly lower tacrolimus trough levels during treatment with flucloxacillin compared with before (p = 0.009) and after flucloxacillin treatment (p = 0.010). In the only available case with concomitant everolimus and flucloxacillin treatment, the same pattern was observed.

Conclusions

Flucloxacillin decreases tacrolimus trough levels, possibly through a CYP3A4 and/or P-gp-inducing effect. It is strongly recommended to closely monitor tacrolimus and everolimus trough levels during flucloxacillin treatment and up to 2 weeks after discontinuation of flucloxacillin.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02968-z) contains supplementary material, which is available to authorized users.

Antifungal prophylaxis and novel drugs in acute myeloid leukemia: the midostaurin and posaconazole dilemma

With the advent of new targeted drugs in hematology and oncology patient prognosis is improved. Combination with antifungal prophylaxis challenges clinicians due to pharmacological profiles prone to drug–drug interactions (DDI). Midostaurin is a novel agent for FLT3-TKD/-ITD^mut-acute myeloid leukemia (AML) and metabolized via cytochrome P450 3A4 (CYP3A4). Posaconazole is a standard of care antifungal agent used for prophylaxis during induction treatment of AML and a strong CYP3A4 inhibitor. Concomitant administration of both drugs leads to elevated midostaurin exposure. Both drugs improve overall survival at low numbers needed to treat. The impact of CYP3A4-related DDI remains to be determined. Severe adverse events have been observed; however, it remains unclear if they can be directly linked to DDI. The lack of prospective clinical studies assessing incidence of invasive fungal infections and clinical impact of DDI contributes to neglecting live-saving antifungal prophylaxis. Management strategies to combine both drugs have been proposed, but evidence on which approach to use is scarce. In this review, we discuss several approaches in the specific clinical setting of concomitant administration of midostaurin and posaconazole and give examples from everyday clinical practice. Therapeutic drug monitoring will become increasingly important to individualize and personalize antineoplastic concomitant and antifungal treatment in the context of DDI. Pharmaceutical companies addressing the issue in clinical trials may take a pioneer role in this field. Other recently developed and approved drugs for the treatment of AML likely inhere potential of DDI marking a foreseeable issue in future treatment of this life-threatening disease.

Administration and Dosing of Systemic Antifungal Agents in Pediatric Patients

Neonates and immunosuppressed/immunocompromised pediatric patients are at high risk of invasive fungal diseases. Appropriate antifungal selection and optimized dosing are imperative to the successful prevention and treatment of these life-threatening infections. Conventional amphotericin B was the mainstay of antifungal therapy for many decades, but dose-limiting nephrotoxicity and infusion-related adverse events impeded its use. Despite the development of several new antifungal classes and agents in the past 20 years, and their now routine use in at-risk pediatric populations, data to guide the optimal dosing of antifungals in children are limited. This paper reviews the spectra of activity for approved antifungal agents and summarizes the current literature specific to pediatric patients regarding pharmacokinetic/pharmacodynamic data, dosing, and therapeutic drug monitoring.

Population pharmacokinetics of cyclosporine in Chinese children receiving hematopoietic stem cell transplantation

Cyclosporine (CsA) is characterized by a narrow therapeutic window and high interindividual pharmacokinetic variability, particularly in juvenile patients. The aims of this study were to build a population pharmacokinetic model of CsA in Chinese children with hematopathy who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) and to identify covariates affecting CsA pharmacokinetics. A total of 86 Chinese children aged 8.4 ± 3.8 years (range 1.1–16.8 years) who received allo-HSCT were enrolled. Whole blood samples were collected before allo-HSCT. Genotyping was performed using an Agena MassARRAY system. A total of 1010 trough plasma concentration values of CsA and clinical data were collected. The population pharmacokinetic model of CsA was constructed using nonlinear mixed-effects modeling (NONMEM) software. The stability and performance of the final model were validated using bootstrapping and normalized prediction distribution errors. We showed that a one-compartment model with first-order elimination adequately described the pharmacokinetics of CsA. The typical values for clearance (CL) and volume of distribution (V) were 42.3 L/h and 3100 L, respectively. Body weight, postoperative days, CYP3A4*1 G genotype, estimated glomerular filtration rate and coadministration of triazole antifungal drugs were identified as significant covariates for CL. Weight and postoperative days were significant covariates for the V of CsA. Our model can be adopted to optimize the CsA dosing regimen for Chinese children with hematopathy receiving allo-HSCT.

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.

ESCMID-ECMM guideline: diagnosis and management of invasive aspergillosis in neonates and children

SCOPE

Presenting symptoms, distributions and patterns of diseases and vulnerability to invasive aspergillosis (IA) are similar between children and adults. However, differences exist in the epidemiology and underlying conditions, the usefulness of newer diagnostic tools, the pharmacology of antifungal agents and in the evidence from interventional phase 3 clinical trials. Therefore, the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) and the European Confederation of Medical Mycology (ECMM) have developed a paediatric-specific guideline for the diagnosis and management of IA in neonates and children.

METHODS

Review and discussion of the scientific literature and grading of the available quality of evidence was performed by the paediatric subgroup of the ESCMID-ECMM-European Respiratory Society (ERS) Aspergillus disease guideline working group, which was assigned the mandate for the development of neonatal- and paediatric-specific recommendations.

QUESTIONS

Questions addressed by the guideline included the epidemiology of IA in neonates and children; which paediatric patients may benefit from antifungal prophylaxis; how to diagnose IA in neonates and children; which antifungal agents are available for use in neonates and children; which antifungal agents are suitable for prophylaxis and treatment of IA in neonates and children; what is the role of therapeutic drug monitoring of azole antifungals; and which management strategies are suitable to be used in paediatric patients. This guideline provides recommendations for the diagnosis, prevention and treatment of IA in the paediatric population, including neonates. The aim of this guideline is to facilitate optimal management of neonates and children at risk for or diagnosed with IA.

Endemic fungal infections in solid organ transplant recipients-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention and management of blastomycosis, histoplasmosis, and coccidioidomycosis in the pre- and post-transplant period. Though each of these endemic fungal infections has unique epidemiology and clinical manifestations, they all share a predilection for primary pulmonary infection and may cause disseminated infection, particularly in immunocompromised hosts. Culture remains the gold standard for definitive diagnosis, but more rapid diagnosis may be achieved with direct visualization of organisms from clinical specimens and antigen-based enzyme immunoassay assays. Serology is of limited utility in transplant recipients. The mainstay of treatment for severe infections remains liposomal amphotericin followed by a step-down azole therapy. Cases of mild to moderate severity with no CNS involvement may be treated with azole therapy alone. The newer generation azoles provide additional treatment options, but supported currently with limited clinical efficacy data. Azole therapy in transplant recipients presents a unique challenge owing to the drug-drug interactions with immunosuppressant agents. Therapeutic drug monitoring of azole levels is an essential component of effective and safe therapy. Infection prevention centers around minimizing epidemiological exposures, early clinical recognition, and azole prophylaxis in selected individuals.

Dermatological Disorders following Liver Transplantation: An Update

Patients undergoing liver transplantation (LT) are at a high risk of dermatological complications compared to the general population as a result of long-term use of immunosuppressant. However, the risk is not as high as other solid organ transplantations (SOT), particularly for skin cancer. The liver is considered as an immune privileged organ since it has a low prevalence of humoral rejection in contrast to other SOT, and thus, LT requires a minimal amount of immunosuppressants compared to other SOT recipients. However, because of the large volume of the liver, patients with LT have higher donor lymphocytes that sometimes may trigger graft-versus-host-disease, yet it is rare. On the other hand, the vast majority of the nonspecific dermatological lesions linked with cirrhosis improve after removal of diseased liver or due to the immunosuppressant used after LT. Nevertheless, dermatological infections related to bacteria, viruses, and fungus after LT are not uncommon. Additionally, the incidence of IgE-mediated food allergies develops in 12.2% of LT patients and may present as life-threatening conditions such as urticaria and/or angioedema and hypersensitivity. Moreover, skin malignancies after LT are a matter of concern. Thus, posttransplant dermatological care should be provided to all LT patients for any suspicious dermatological lesions. Our goal is to give an outline of the dermatological manifestation associated with LT for the clinicians by collecting the published data from all archived case reports.

A case report of disseminated histoplasmosis and concurrent cryptococcal meningitis in a patient treated with ruxolitinib

Background

Ruxolitinib is a highly potent janus kinase inhibitor that places its users at risk for various bacterial infections and viral reactivation. However new reports are also emerging that suggest greater immunosuppression and risk for fungal disease.

Case presentation

We report the case of a 51 year-old veteran from Guam, treated with ruxolitinib for polycythemia vera, who developed disseminated histoplasmosis and concurrent cryptococcal meningitis.

Conclusion

This case draws attention to the degree of immunosuppression that may be seen with this drug and the need for heightened vigilance for opportunistic infections in those treated with inhibitors of janus kinase/signal transducers and activators of transcription (JAK/STAT) such as ruxolitinib.

Strategies for Antimicrobial Stewardship in Solid Organ Transplant Recipients

Complications of antimicrobial therapy, such as multidrug-resistant organisms and Clostridium difficile, commonly affect solid-organ transplant recipients and have been associated with graft loss and mortality. Although opportunities are abundant, antimicrobial stewardship practices guiding appropriate therapy have been infrequently reported in transplant patients. A patient-centered, multidisciplinary structure, using established antimicrobial optimization principles, is needed to create nuanced approaches to protect patients and antimicrobials and improve outcomes.

Effects of clotrimazole troches on tacrolimus dosing in heart transplant recipients

BACKGROUND

Tacrolimus is a cornerstone of immunosuppression after transplantation but is highly susceptible to changes from interacting variables and has a narrow therapeutic index. Clotrimazole troches are commonly used as a non-systemic antifungal to prevent oral candidiasis. Studies suggest that clotrimazole troches, though minimally absorbed systemically, may affect tacrolimus concentrations by inhibition of metabolic enzyme activity in the intestines. However, the magnitude of the impact of clotrimazole on tacrolimus dosing requirements to maintain goal levels is not well described.

METHODS

To assess this, tacrolimus dose adjustments and trough concentrations were retrospectively examined in 95 heart transplant recipients before and after the discontinuation of clotrimazole.

RESULTS

The median percent tacrolimus dose change was an increase of 66.7% (IQR 28.6%, 100%) after clotrimazole discontinuation, and the median trough concentration percent change from baseline to the first trough after clotrimazole discontinuation (in the absence of a dose change) was -42.5% (IQR -52.3%, -30.9%). Five cases of allograft rejection were observed.

CONCLUSION

In conclusion, clotrimazole troches exert a meaningful interaction with tacrolimus that requires close monitoring and dose adjustment. The data from this single-center study provide novel information that could guide providers on the degree of tacrolimus dose adjustment needed when discontinuing clotrimazole prophylaxis after heart transplantation.

Synthesis, Single Crystal X-ray Analysis, and Antifungal Profiling of Certain New Oximino Ethers Bearing Imidazole Nuclei

Fungal infections threaten human health, particularly in immune-compromised patients worldwide. Although there are a large number of antifungal agents available, the desired clinical attributes for the treatment of fungal infections have not yet been achieved. Azoles are the mainstay class of the clinically used antifungal agents. In the current study, the synthesis, spectroscopic characterization, and antifungal activity of certain new oximino ethers Va–n bearing imidazole nuclei are reported. The (E)-configuration of the imine double bond of the synthesized compounds Va–n has been confirmed via single crystal X-ray analysis of compound Vi as a representative example of this class of compounds. The molecular structure of compound Vi was crystallized in the monoclinic, P2₁/c, a = 18.7879(14) Å, b = 5.8944(4) Å, c = 16.7621(12) Å, β = 93.063(3)°, V = 1855.5(2) ų, Z = 4. The in vitro antifungal activity of the synthesized compounds Va–n were evaluated using diameter of the inhibition zone (DIZ) and minimum inhibitory concentration (MIC) assays against different fungal strains. Compound Ve manifested anti-Candida albicans activity with an MIC value of 0.050 µmol/mL, being almost equipotent with the reference antifungal drug fluconazole (FLC),while compounds Vi and Vn are the most active congeners against Candida parapsilosis, being equipotent and about twenty-three times more potent than FLC with an MIC value of 0.002 µmol/mL. The results of the current report might support the development of new potent and safer antifungal azoles.

Drug-drug interactions between triazole antifungal agents used to treat invasive aspergillosis and immunosuppressants metabolized by cytochrome P450 3A4

Patients undergoing treatment with immunosuppressant drugs following solid organ or hematopoietic stem cell transplantation are at particular risk for development of serious infections such as invasive aspergillosis. Four triazole antifungal drugs, voriconazole, posaconazole, itraconazole, and isavuconazole, are approved to treat invasive aspergillosis either as first- or second-line therapy. All of these agents are inhibitors of cytochrome P450 3A4, which plays a key role in metabolizing immunosuppressant drugs such as cyclosporine, tacrolimus, and sirolimus. Thus, co-administration of a triazole antifungal drug with these immunosuppressant drugs can potentially increase plasma concentrations of the immunosuppressant drugs, thereby resulting in toxicity, or upon discontinuation, inadvertently decrease the respective concentrations with increased risk of rejection or graft-versus-host disease. In this article, we review the evidence for the extent of inhibition of cytochrome P450 3A4 by each of these triazole antifungal drugs and assess their effects on cyclosporine, tacrolimus, and sirolimus. We also consider other factors affecting interactions of these two classes of drugs. Finally, we examine recommendations and strategies to evaluate and address those potential drug-drug interactions in these patients.

Antifungal stewardship considerations for adults and pediatrics

Antifungal stewardship refers to coordinated interventions to monitor and direct the appropriate use of antifungal agents in order to achieve the best clinical outcomes and minimize selective pressure and adverse events. Antifungal utilization has steadily risen over time in concert with the increase in number of immunocompromised adults and children at risk for invasive fungal infections (IFI). Challenges in diagnosing IFI often lead to delays in treatment and poorer outcomes. There are also emerging data linking prior antifungal exposure and suboptimal dosing to the emergence of antifungal resistance, particularly for Candida. Antimicrobial stewardship programs can take a multi-pronged bundle approach to ensure suitable prescribing of antifungals via post-prescription review and feedback and/or prior authorization. Institutional guidelines can also be developed to guide diagnostic testing in at-risk populations; appropriate choice, dose, and duration of antifungal agent; therapeutic drug monitoring; and opportunities for de-escalation and intravenous-to-oral conversion.

The role of the multidisciplinary team in antifungal stewardship

There are a variety of challenges faced in the management of invasive fungal diseases (IFD), including high case-fatality rates, high cost of antifungal drugs and development of antifungal resistance. The diagnostic challenges and poor outcomes associated with IFD have resulted in excessive empirical use of antifungals in various hospital settings, exposing many patients without IFD to potential drug toxicities as well as causing spiralling antifungal drug costs. Further complexity arises as different patient groups show marked variation in their risk for IFD, fungal epidemiology, sensitivity and specificity of diagnostic tests and the pharmacokinetics and pharmacodynamics of antifungal drugs. To address these issues and to ensure optimal management of IFD, specialist knowledge and experience from a range of backgrounds is required, which extends beyond the remit of most antibiotic stewardship programmes. The first step in the development of any antifungal stewardship (AFS) programme is to build a multidisciplinary team encompassing the necessary expertise in the management of IFD to develop and implement the AFS programme. The specific roles of the key individuals within the AFS team and the importance of collaboration are discussed in this article.

Cutaneous phaeohyphomycosis in a hematopoietic stem cell transplant patient caused by Alternaria rosae: First case report

Alternaria species have been reported as a rare cause of fungal infection in organ and stem cell transplant recipients, but to date, no reports have been published of infection in humans caused by Alternaria rosae. Here, we report cutaneous A. rosae infection in a 66-year-old farmer with a history of primary myelofibrosis who had undergone allogeneic unrelated donor hematopoietic stem cell transplantation. Forty-nine days post transplant, he presented with a nodule on the thumb with no findings suggestive of disseminated infection. Pathology, culture, and molecular speciation showed the nodule was caused by cutaneous A. rosae. He had been on voriconazole as antifungal prophylaxis, but was found to have a subtherapeutic voriconazole level. He was switched to posaconazole based on published in vitro data showing its superior efficacy in Alternaria treatment. Susceptibility testing showed that the A. rosae isolate was indeed susceptible to posaconazole. His cutaneous lesion remained stable, but he died from respiratory failure secondary to lobar pneumonia. At lung autopsy, A. rosae was not identified in the lungs. We believe this to be the first published report, to our knowledge, of A. rosae infection in humans.

Efficacy of Propolis on the Denture Stomatitis Treatment in Older Adults: A Multicentric Randomized Trial

Our hypothesis tested the efficacy and safety of a mucoadhesive oral gel formulation of Brazilian propolis extract compared to miconazole oral gel for the treatment of denture stomatitis due to Candida spp. infection in older adults. Forty patients were randomly allocated in a noninferiority clinical trial into two groups. The control group (MIC) received 20 mg/g miconazole oral gel and the study group (PROP) received mucoadhesive formulation containing standardized extract of 2% (20 mg/g) propolis (EPP-AF®) during 14 days. Patients were examined on days 1, 7, and 14. The Newton's score was used to classify the severity of denture stomatitis. The colony forming unity count (CFU/mL) was quantified and identified (CHROMagar Candida®) before and after the treatment. Baseline characteristics did not differ between groups. Both treatments reduced Newton's score (P < 0.0001), indicating a clinical improvement of the symptoms of candidiasis with a clinical cure rate of 70%. The microbiological cure with significant reduction in fungal burden on T14 was 70% in the miconazole group and 25% in the EPP-AF group. The EPP-AF appears to be noninferior to miconazole considering the clinical cure rate and could be recommended as an alternative treatment in older patients.

Dried Blood Spot sampling in psychiatry: Perspectives for improving therapeutic drug monitoring

Assessment of drug concentrations is indicated to guide dosing of a selected number of drugs used in psychiatry. Conventionally this is done by vena puncture. Novel sampling strategies such as dried blood spot (DBS) sampling have been developed for various drugs, including antipsychotics, antidepressants and mood-stabilizers. DBS sampling is typically performed by means of a finger prick. This method allows for remote sampling, which means that patients are not required to travel to a health care facility. The number of DBS assays for drugs used in psychiatry has increased over the last decade and includes antidepressants (tricyclic and serotonin and/or norepinephrine reuptake inhibitors), mood stabilizers and first- and second-generation antipsychotics. Available assays often comply with analytical validation criteria but are seldom used in routine clinical care. Little attention has been paid to the clinical validation and implementation processes of home sampling. Ideally, not only medicines but also clinical chemistry parameters should be measured within the same sample. This article reflects on the position of DBS remote sampling in psychiatry and provides insight in the requisites of making such a sampling tool successful.

Betel Nut Chewing Is Associated With Reduced Tacrolimus Concentration in Taiwanese Liver Transplant Recipients

PURPOSE

Studies have shown that arecoline, the major alkaloid component of betel nuts, alters the activity of enzymes in the cytochrome P450 (CYP-450) family. Tacrolimus, an immunosuppressant that protects against organ rejection in transplant recipients, not only is mainly metabolized by CYP3A enzymes but also has a narrow therapeutic range. We aimed to investigate whether dose-adjusted blood trough levels of tacrolimus differed over time between betel nut-chewing and non-betel nut-chewing liver transplant recipients.

METHODS

In this retrospective case-control study, 14 active betel nut-using liver recipients were matched at a 1:2 ratio to 28 non-betel nut-using liver recipients by sex, age, graft source, duration of follow-up after liver transplantation, and estimated glomerular filtration rate. Differences in liver function index, renal function index, and dose-adjusted blood trough levels of tacrolimus over an 18-month period were compared between the 2 groups by using the Generalized Estimating Equation approach.

RESULTS

Dose-adjusted blood trough levels of tacrolimus tended to be significantly (P = .04) lower in betel nut chewers (mean = 0.81, medium = 0.7, 95% confidence interval [CI] = 0.73 to 0.90) than in nonchewers (mean = 1.12, medium = 0.88, 95% CI = 1.03 to 1.22) during the 18-month study period. However, there was no significant difference in renal and liver function index between the 2 groups.

CONCLUSION

Liver transplant recipients receiving tacrolimus tend to have lower blood trough levels of the drug over time if they chew betel nuts.

Studies on the interaction between promethazine and human serum albumin in the presence of flavonoids by spectroscopic and molecular modeling techniques

Fluorescence, absorption, time-correlated single photon counting (TCSPC), and circular dichroism (CD) spectroscopic techniques as well as molecular modeling methods were used to study the binding characterization of promethazine (PMT) to human serum albumin (HSA) and the influence of flavonoids, rutin and baicalin, on their affinity. The results indicated that the fluorescence quenching mechanism of HSA by PMT is a static quenching due to the formation of complex. The reaction was spontaneous and mainly mediated by hydrogen bonds and hydrophobic interactions. The binding distance between the tryptophan residue of HSA and PMT is less than 8nm, which indicated that the energy transfer from the tryptophan residue of HSA to PMT occurred. The binding site of PMT on HSA was located in sites I and the presence of PMT can cause the conformational changes of HSA. There was the competitive binding to HSA between PMT and flavonoids because of the overlap of binding sites in HSA. The flavonoids could decrease the association constant and increase the binding distance. In addition, their synergistic effect can further change the conformation of HSA. The decrease in the affinities of PMT binding to HSA in the presence of flavonoids may lead to the increase of free drug in blood, which would affect the transportation or disposition of drug and evoke an adverse or toxic effect. Hence, rationalising dosage and diet regimens should be taken into account in clinical application of PMT.

Effects of CYP3A5 polymorphism on the pharmacokinetics of a once-daily modified-release tacrolimus formulation and acute kidney injury in hematopoietic stem cell transplantation

Background

Tacrolimus is metabolized by cytochrome P450 (CYP) 3A4 and 3A5. We investigated the influence of CYP3A5 polymorphism and concurrent use of azole antifungal agents (AZ) on the pharmacokinetics of a once-daily modified-release tacrolimus formulation (Tac-QD) in patients after hematopoietic stem cell transplantation (HSCT).

Design and methods

Twenty-four patients receiving allogeneic HSCT were enrolled. Genotyping for CYP3A5*3 was done by a PCR-restriction fragment length polymorphism method. Trough blood concentrations (C₀) of tacrolimus were measured by chemiluminescence magnetic microparticle immunoassay. Continuous infusion of tacrolimus was administered from the day before transplantation and was switched to Tac-QD after adequate oral intake.

Results

Thirteen patients had a CYP3A5*3/*3 genotype, and 11 patients had a CYP3A5*1/*1 or *1/*3 genotype. No significant difference was observed in daily dosages and the C₀ of tacrolimus between the two genotype groups without AZ. However, in patients who were co-administered AZ, the C₀ values of tacrolimus were higher in patients with the CYP3A5*3/*3 allele than with the CYP3A5*1 allele (P = 0.034), although daily doses of Tac-QD in patients with CYP3A5*3/*3 were significantly lower than those with the CYP3A5*1 allele (P = 0.041). The cumulative incidence of acute kidney injury was higher in patients with the CYP3A5*3/*3 than with the CYP3A5*1 allele when AZ was co-administered. The decrement for daily dosage of Tac-QD was significantly greater in patients expressing the CYP3A5*3/*3 than the CYP3A5*1 allele.

Conclusions

CYP3A5 genotyping may be useful for safe and effective immunosuppressive therapy with Tac-QD in HSCT patients in whom the use of AZ is anticipated.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-016-3060-4) contains supplementary material, which is available to authorized users.

A clinically relevant pharmacokinetic interaction between cyclosporine and imatinib

Purpose

Cyclosporine A (CsA) and imatinib are both CYP3A4 and P-glycoprotein substrates. Concomitant use after hematopoietic stem cell transplantation (HSCT) for chronic myeloid leukemia (CML) or Philadelphia chromosome-positive (Ph+) acute lymphatic leukemia (ALL) may therefore result in a pharmacokinetic interaction. Although case reports and a recent small study in children indeed suggested there is a relevant pharmacokinetic interaction, a larger study in adults is lacking. In this study, we assessed the presence and extent of this interaction in patients with CML or Ph+ ALL undergoing HSCT.

Methods

From a large database containing data of all patients receiving HSCT in our center between 2005 and 2015, we selected 16 patients using this drug combination. The average dose-corrected CsA concentration was calculated before and after initiation of imatinib.

Results

The average dose-corrected CsA concentration increased during imatinib use in all patients, on average by 94 % (p < 0.001). Based on measured drug concentrations, the CsA dosage needed to be reduced, on average, by 27 % after initiation of imatinib (p = 0.004).

Conclusions

Imatinib significantly increases CsA concentrations in HSCT patients, putting these patients at increased risk of CsA toxicity. We recommend intensive monitoring of CsA concentrations after initiation of imatinib; a pre-emptive CsA dose reduction of 25 % might be considered.