Comparing Azole Plasma Trough Levels in Lung Transplant Recipients: Percentage of Therapeutic Levels and Intrapatient Variability

Population pharmacokinetics and covariate-based dosing individualization of voriconazole in lung transplant recipients

This study aimed to explore pharmacokinetics of voriconazole and its covariates in lung transplant recipients using population approach in order to propose dosing individualization. Data from routine therapeutic drug monitoring in adult lung transplant recipients treated with oral voriconazole were analysed with a three-stage population pharmacokinetic model using nonlinear mixed-effects modelling. Monte Carlo simulations based on final voriconazole pharmacokinetic model were used to generate the theoretical distribution of pharmacokinetic profiles at various dosing regimens. A total of 78 voriconazole serum concentrations collected from 40 patients were included in pharmacokinetic analysis. The only significant covariate was age for voriconazole clearance. Population voriconazole apparent clearance started at 32.26 L/h and decreased by 0.021 L/h with each year of patient's age, while population apparent volume of distribution was 964.46 L. Based on this model, we have proposed an easy-to-use dosing regimen consisting of a loading dose of 400 mg every 12 h for the first 48 h of treatment followed by maintenance dose of 300 mg every 12 h in patients aged up to 59 years, or by maintenance dose of 200 mg every 12 h in patients aged above 59 years.

Dosing Optimization of Posaconazole in Lung-Transplant Recipients Based on Population Pharmacokinetic Model

Although posaconazole tablets show relatively low variability in pharmacokinetics (PK), the proportion of patients achieving the PK/PD target at the approved uniform dose for both prophylaxis and therapy is not satisfactory. The aim of this study was to develop a posaconazole population PK model in lung-transplant recipients and to propose a covariate-based dosing optimization for both prophylaxis and therapy. In this prospective study, 80 posaconazole concentrations obtained from 32 lung-transplant patients during therapeutic drug monitoring were analyzed using nonlinear mixed-effects modelling, and a Monte Carlo simulation was used to describe the theoretical distribution of posaconazole PK profiles at various dosing regimens. A one-compartment model with both linear absorption and elimination best fit the concentration-time data. The population apparent volume of distribution was 386.4 L, while an apparent clearance of 8.8 L/h decreased by 0.009 L/h with each year of the patient's age. Based on the covariate model, a dosing regimen of 200 mg/day for prophylaxis in patients ˃60 years, 300 mg/day for prophylaxis in patients ˂60 years and for therapy in patients ˃60 years, and 400 mg/day for therapy in patients ˂60 years has been proposed. At this dosing regimen, the PK/PD target for prophylaxis and therapy is reached in 95% and 90% of population, respectively, representing significantly improved outcomes in comparison with the uniform dose.

Subtherapeutic concentrations of posaconazole tablet: determining risk factors and effectiveness of a standardized dose adjustment in hematology inpatients

Posaconazole is indicated for antifungal prophylaxis in hematology patients at high-risk of invasive fungal infections (IFI). Consensus guidelines recommend maintaining steady-state trough concentrations above 0.7 mg/L; however, upto one-third of patients return subtherapeutic concentrations which is associated with breakthrough IFI. This retrospective observational study of 496 concentrations from 90 hematology inpatients prescribed posaconazole tablet (PCZ-tab) between May 2017 and May 2019 identified 24% (n = 121) of posaconazole concentrations were subtherapeutic after the dosage of 300 mg daily. On multivariable analyses, diarrhea (p = 0.002), male gender (p = 0.018), and concurrent regular metoclopramide (p = 0.002) were significantly associated with subtherapeutic posaconazole concentrations. Eighty-nine percent of patients (n = 16) who underwent dose adjustment to 200 mg twice daily successfully achieved target posaconazole concentrations at first steady-state measurement. This study confirms that therapeutic drug monitoring of posaconazole remains necessary as subtherapeutic posaconazole concentrations are relatively common, and that dose adjustment of 200 mg twice daily, safely enabled achievement of therapeutic concentrations.

Effects of inflammation on voriconazole levels: a systematic review

AIMS

This study aimed to review the studies evaluating the effect of the inflammatory state on voriconazole (VRZ) levels.

METHODS

The study included randomized clinical trials, cohort studies, and case-control studies that focused on the influence of the inflammatory state on VRZ levels. Following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, relevant articles published until 2021 were searched in several databases, including PubMed, Embase, Web of Science, and the Cochrane Library.

RESULTS

Twenty studies were included in this review, of which 15 described adult populations, 3 described pediatric populations, and 2 included both adult and pediatric populations. Seventeen studies used C-reactive protein (CRP) as an indicator of inflammation, 6 described a dose-response relationship for the effect of inflammation represented by CRP on VRZ concentrations, and 4 examined the effect of CRP on the metabolic rate of VRZ.

CONCLUSIONS

Our findings showed that the level of inflammation can significantly affect VRZ levels. However, the effect of inflammation on VRZ concentrations in children is controversial and must be analyzed along with age. Clinicians dosing VRZ should take into account the patient's inflammatory state. The impact of inflammation on genotype-based dosing decisions requires further study to explain the high pharmacokinetic variability of VRZ.

Antifungal Drugs TDM: Trends and Update

PURPOSE

The increasing burden of invasive fungal infections results in growing challenges to antifungal (AF) therapeutic drug monitoring (TDM). This review aims to provide an overview of recent advances in AF TDM.

METHODS

We conducted a PubMed search for articles during 2016-2020 using "TDM" or "pharmacokinetics" or "drug-drug-interaction" with "antifungal," consolidated for each AF. Selection was limited to English language articles with human data on drug exposure.

RESULTS

More than 1000 articles matched the search terms. We selected 566 publications. The latest findings tend to confirm previous observations in real-life clinical settings. The pharmacokinetic variability related to special populations is not specific but must be considered. AF benefit-to-risk ratio, drug-drug interaction (DDI) profiles, and minimal inhibitory concentrations for pathogens must be known to manage at-risk situations and patients. Itraconazole has replaced ketoconazole in healthy volunteers DDI studies. Physiologically based pharmacokinetic modeling is widely used to assess metabolic azole DDI. AF prophylactic use was studied more for Aspergillus spp. and Mucorales in oncohematology and solid organ transplantation than for Candida (already studied). Emergence of central nervous system infection and severe infections in immunocompetent individuals both merit special attention. TDM is more challenging for azoles than amphotericin B and echinocandins. Fewer TDM requirements exist for fluconazole and isavuconazole (ISZ); however, ISZ is frequently used in clinical situations in which TDM is recommended. Voriconazole remains the most challenging of the AF, with toxicity limiting high-dose treatments. Moreover, alternative treatments (posaconazole tablets, ISZ) are now available.

CONCLUSIONS

TDM seems to be crucial for curative and/or long-term maintenance treatment in highly variable patients. TDM poses fewer cost issues than the drugs themselves or subsequent treatment issues. The integration of clinical pharmacology into multidisciplinary management is now increasingly seen as a part of patient care.

State of the art in cystic fibrosis pharmacology optimization of antimicrobials in the treatment of cystic fibrosis pulmonary exacerbations: III. Executive summary

Acute pulmonary exacerbations are complications of cystic fibrosis (CF) and are associated with increased morbidity and mortality. Methicillin-resistant Staphylococcus aureus (MRSA) and Aspergillus fumigatus are organisms that have been detected in the lungs of CF patients. The focus of this review is to provide an overview of the classes of antimicrobials used for MRSA and allergic bronchopulmonary aspergillosis (ABPA), a hypersensitivity reaction caused by A. fumigatus. The current anti-MRSA antibiotics and medications for ABPA dosing recommendations are discussed. This article also reviews the findings from the MRSA utilization surveys and the pharmacokinetic and pharmacodynamic differences between CF and non-CF patients. Antimethicillin S. aureus antibiotics include ceftaroline, clindamycin, fluoroquinolone derivatives (ciprofloxacin, levofloxacin), glycopeptide derivatives (telavancin, vancomycin), linezolid, rifampin, sulfamethoxazole/trimethoprim, and tetracycline derivatives (doxycycline, minocycline, tigecycline). Medications used for ABPA include corticosteroids, amphotericin B, azole antifungals (isavuconazole, itraconazole, posaconazole, voriconazole), and a monoclonal antibody, omalizumab.

Comparing posaconazole and itraconazole for antifungal prophylaxis in critically ill lung transplant recipients: Efficacy and plasma concentrations

BACKGROUND

Posaconazole and itraconazole are commonly used for systemic antifungal prophylaxis after lung transplantation. The aim of this study on critically ill lung transplant recipients was to assess the rate of adequate plasma concentrations and the frequency of fungal-induced transitions from antifungal prophylaxis to therapy after the administration of either posaconazole or itraconazole for systemic prophylaxis.

METHODS

Critically ill lung transplant recipients with postoperative posaconazole or itraconazole prophylaxis and therapeutic drug monitoring from February 2016 to November 2019 were retrospectively included in the study. Positive fungal cultures or Aspergillus antigen tests resulting in a transition from antifungal prophylaxis to therapy were analyzed from the first day of prophylaxis until 7 days after the last sample for each patient. Adequate plasma concentrations were defined as ≥500 µg/L for itraconazole and ≥700 µg/L for posaconazole.

RESULTS

Two hundred seventy-five samples from 73 patients were included in the analysis. Overall, 60% of the posaconazole and 55% of the itraconazole concentrations were subtherapeutic. Administration of posaconazole suspension resulted significantly (P < .01) more often in subtherapeutic concentrations than tablets (68% vs 10%). Patients treated with posaconazole showed less positive fungal records resulting in a transition from prophylaxis to therapy than patients treated with itraconazole (10% vs 33%, P-value: .029). The detection of a fungal pathogen was not associated with the measured plasma concentrations or the achievement of the target concentrations.

CONCLUSION

Our findings suggest that posaconazole should be used instead of itraconazole for systemic prophylaxis in critically ill lung transplant recipients.

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

A novel highly bio-available itraconazole formulation (SUBA®-Itraconazole) for anti-fungal prophylaxis in lung transplant recipients

BACKGROUND

Antifungal prophylaxis remains a mainstay of lung transplantation, given invasive fungal infection is a common and serious complication after lung transplantation. Choice of systemic agent to prevent invasive fungal infection varies between centers and funding of agents remains challenging. Our center has recently changed from posaconazole to a highly bioavailable formulation of itraconazole (SUBA®-itraconazole) at substantially reduced cost, but safety and toxicity require further assessment. A retrospective study of lung transplant patients receiving systemic antifungal prophylaxis from December 2016 through December 2019 following change from posaconazole to itraconazole as standard practice. 150 patients with lung transplants were managed in this time period, with 88 (59%) receiving at least 1 mold-active triazole during the study period. 48 (58%) of these patients received SUBA®-itraconazole; 68 (82%) received posaconazole and 10 (12%) received voriconazole. The average cost per patient during the study period was significantly lower on SUBA®-itraconazole (mean $1548/patient/6 month course) than posaconazole (mean $16 921.35/patient/6 month course). Target trough concentrations for prophylaxis of itraconazole > 0.5 mg/L and posaconazole > 0.7 mg/L were achieved on empiric dosing in 49% and 68% respectively. Overall trough itraconazole (0.50 vs 1.12 mg/L, P < .001) and posaconazole (1.37 vs 2.10 mg/L P < .001) concentrations were significantly lower in patients with cystic fibrosis. Calcineurin inhibitor dose changes on introduction or cessation were similar for SUBA®-itraconazole and posaconazole. Breakthrough invasive fungal infection and toxicity were rare. SUBA®-itraconazole is well-tolerated, associated with rare breakthrough invasive fungal infection, and lower cost. Prospective studies following general introduction are required to determine long-term safety, tolerability, and efficacy.

Review of Pharmacologic Considerations in the Use of Azole Antifungals in Lung Transplant Recipients

Mold-active azole antifungals are commonly prescribed for the prevention of invasive fungal infections in lung transplant recipients. Each agent exhibits a unique pharmacologic profile, an understanding of which is crucial for therapy selection and optimization. This article reviews pharmacologic considerations for three frequently-used azole antifungals in lung transplant recipients: voriconazole, posaconazole, and isavuconazole. Focus is drawn to analysis of drug-interactions, adverse drug reactions, pharmacokinetic considerations, and the role of therapeutic drug monitoring with special emphasis on data from the post-lung transplant population.

Pharmacokinetics and Pharmacodynamics of Posaconazole

Posaconazole is typically used for preventing invasive yeast and mold infections such as invasive aspergillosis in high-risk immunocompromised patients. The oral suspension was the first released formulation and many pharmacokinetic and pharmacodynamic studies of this formulation have been published. Erratic absorption profiles associated with this formulation were widely reported. Posaconazole exposure was found to be significantly influenced by food and many gastrointestinal conditions, including pH and motility. As a result, low posaconazole plasma concentrations were obtained in large groups of patients. These issues of erratic absorption urged the development of the subsequently marketed delayed-release tablet, which proved to be associated with higher and more stable exposure profiles. Shortly thereafter, an intravenous formulation was released for patients who are not able to take oral formulations. Both new formulations require a loading dose on day 1 to achieve high posaconazole concentrations more quickly, which was not possible with the oral suspension. So far, there appears to be no evidence of increased toxicity correlated to the higher posaconazole exposure achieved with the regimen for these formulations. The higher systemic availability of posaconazole for the delayed-release tablet and intravenous formulation have resulted in these two formulations being preferable for both prophylaxis and treatment of invasive fungal disease. This review aimed to integrate the current knowledge on posaconazole pharmacokinetics, pharmacodynamics, major toxicity, existing resistance, clinical experience in special populations, and new therapeutic strategies in order to get a clear understanding of the clinical use of this drug.

Optimization of antimicrobials in the treatment of cystic fibrosis pulmonary exacerbations: II. Therapies for allergic bronchopulmonary aspergillosis

This review is the second article in the State-of-the-Art series and aims to evaluate medications used in the treatment of allergic bronchopulmonary aspergillosis (ABPA) in pediatric and adult patients with cystic fibrosis (CF). ABPA is one of several organisms that are found in the airways of CF patients. This review provides an evidence-based summary of pharmacokinetic (PK)/pharmacodynamic (PD), tolerability, and efficacy studies of medications including corticosteroids, amphotericin B, azole antifungals (isavuconazole, itraconazole, posaconazole, and voriconazole), and a monoclonal antibody omalizumab in the treatment of ABPA and identifies areas where further study is warranted.

Tablets or oral suspension for posaconazole in lung transplant recipients? Consequences for trough concentrations of tacrolimus and everolimus

AIMS

A new formulation of posaconazole (PCZ), delayed-release tablets (PCZ-tab), increases PCZ bioavailability and plasma trough concentrations (C_min ) over those achieved with an oral suspension (PCZ-susp). PCZ is an inhibitor of cytochrome P450 3A4 and P-glycoprotein. We therefore investigated the impact of PCZ-tab treatment on blood C_min and doses of tacrolimus (TAC) and everolimus (EVR).

METHODS

Eighteen lung transplant patients receiving TAC (n = 13) or TAC + EVR (n = 5) between June 2015 and March 2016 were retrospectively included. Ten of these patients received both PCZ-tab and PCZ-susp (i.e. switched patients); the other 8 received only PCZ-tab. Plasma C_min of PCZ (n = 64), blood C_min of TAC (n = 299) and EVR (n = 80) were determined during routine therapeutic drug monitoring by liquid chromatography-tandem mass spectrometry.

RESULTS

PCZ C_min on PCZ-tab treatment (n = 48) was 2.5 times higher than that on PCZ-susp therapy (n = 16), for both PCZ patients (P < .0001) and for switched patients (P = .003). PCZ initiation, regardless of galenic form, increased TAC and EVR C_min adjusted for dose (D), 3-fold and 3.5-fold, respectively (P < .0001 for both). PCZ-tab treatment was associated with a higher TAC C_min /D (PCZ-tab vs PCZ-susp: 0.004 ± 0.004 L^-1 vs 0.009 ± 0.006 L^-1 , P < .0001) and lower TAC daily dose than PCZ-susp (PCZ-tab vs PCZ-susp: 1.08 ± 0.92 vs 2.32 ± 1.62 mg d^-1 , P < .0001). EVR C_min /D was higher and EVR dose tended to be lower on PCZ-tab than on PCZ-susp.

CONCLUSION

The greater PCZ exposure achieved during PCZ-tab treatment increased drug-drug interactions with TAC and EVR, resulting in greater exposure, potentially exposing patients to higher risks of adverse effects.

Posaconazole therapy in children with cystic fibrosis and Aspergillus-related lung disease

There is emerging evidence for the role of posaconazole in the management of Aspergillus-related cystic fibrosis (CF) lung disease. The tolerability and efficacy of posaconazole in paediatric CF is not well established. We report a prospective study over a fifty-three month period evaluating the safety, tolerability, and efficacy of posaconazole in pediatric CF. Fourteen children (seven males, median age 13 years, range 3-17 years) received a total of twenty-three courses of posaconazole (13 oral suspension and 10 tablet formulation). Of these patient episodes, nine received posaconazole for emerging or active allergic bronchopulmonary aspergillosis (ABPA) and two required a combination of posaconazole and systemic corticosteroids for difficult-to-treat ABPA. A subgroup of patients (n = 12) with persistent isolates of Aspergillus fumigatus, in the absence of serological markers of ABPA, received posaconazole monotherapy for pulmonary exacerbations not responding to conventional broad-spectrum antibiotic treatment. Posaconazole levels, full blood count, electrolytes, and liver function were monitored on day 7 of treatment and then monthly. Posaconazole was well tolerated in all but three patients. Therapeutic plasma levels >1 mg/l were achieved in all receiving the tablet formulation in comparison to 60% on the liquid preparation. There was a modest but significant improvement in FEV1 (% predicted) demonstrated for the cohort as a whole (p = 0.015) following posaconazole therapy. Posaconazole is well tolerated in children as young as six years old, improvements in lung function are observed, and therapeutic plasma levels are readily achieved in patients taking the tablet formulation and in adherent patients taking the liquid formulation.

Treatment by Posaconazole Tablets, Compared to Posaconazole Suspension, Does Not Reduce Variability of Posaconazole Trough Concentrations

The delayed-release tablet formulation of posaconazole (POS-tab) results in higher plasma POS trough concentrations (C_min) than the oral suspension (POS-susp), which raises the question of the utility of therapeutic drug monitoring (TDM). We aimed to compare the variability of the POS C_min for the two formulations and identify determinants of the POS-tab C_min and its variability. Demographic, biological, and clinical data from 77 allogeneic hematopoietic stem cell transplant patients (874 C_min) treated with POS-tab (n = 41), POS-susp (n = 29), or both (n = 7) from January 2015 to December 2016 were collected retrospectively. Interpatient and within-subject coefficients of variation (CVs) of the C_min adjusted to dose (D) were calculated for each formulation. Between-group comparisons were performed using a linear mixed effects model. The POS C_min was higher for the tablet than for the suspension (median [25th-75th percentile]: 1.8 [1.2-2.4] mg/liter versus 1.2 [0.7-1.6] mg/liter, P < 0.0001). Interpatient CVs for the tablet and suspension were 60.8 versus 63.5% (P = 0.7), whereas within-subject CVs were 39.7 and 44.9%, respectively (P = 0.3). Univariate analysis showed that age and treatment by POS-tab were significantly and positively associated with the POS C_min, whereas diarrhea was associated with a diminished POS C_min Multivariate analysis identified treatment with POS-tab and diarrhea as independent factors of the POS C_min, with a trend toward a lower impact of diarrhea during treatment with POS-tab (P = 0.07). Despite increased POS exposure with the tablet formulation, the variability of the POS C_min was not significantly lower than that of the suspension. This suggests that TDM may still be useful to optimize tablet POS therapy.

Prevention of drug-related complications in cystic fibrosis

PURPOSE OF REVIEW

Due to continuous development of new drugs and better treatment strategies, survival of patients with cystic fibrosis has changed dramatically. Recently, targeted therapy of cystic fibrosis transmembrane conductance regulator (CFTR) modulators have become available. Despite these promising developments, treatment of this complex multiorgan disease constitutes a high and variable amount of other drugs. Complications of pharmacotherapeutic treatment are, therefore, expected to become more prevalent. This gives cause to review drug-related side effects in this new era in cystic fibrosis treatment.

RECENT FINDINGS

We will discuss cystic fibrosis-related pharmacotherapies with a focus on indication of treatment, side effects and their complications, drug--drug interactions, and options to monitor and prevent drug-induced toxicity. Many recent publications about pharmacotherapy in cystic fibrosis, focus on antifungal therapy and CFTR modulators. We will give an overview of the most important studies.

SUMMARY

With increased life expectancy which is, in part, because of better treatment options, the burden of pharmacotherapy in cystic fibrosis patients will increase. This has a high impact on quality of life as pharmacotherapy is time consuming and may cause side effects. Therefore, it is very important to be aware of possible pharmacotherapy-related side effects and their complications, drug--drug interactions, and options to monitor and prevent drug-induced toxicity.

Single-centre study of therapeutic drug monitoring of posaconazole in lung transplant recipients: factors affecting trough plasma concentrations

Objectives

This study describes therapeutic drug monitoring (TDM) of posaconazole suspension and modified release (MR) tablets in lung transplant (LTx) recipients and evaluates factors that may affect posaconazole trough plasma concentration (Cmin).

Methods

A single-centre, retrospective study evaluating posaconazole Cmin in LTx recipients receiving posaconazole suspension or MR tablets between January 2014 and December 2016.

Results

Forty-seven LTx patients received posaconazole suspension, and 78 received the MR tablet formulation; a total of 421 and 617 Cmin measurements were made, respectively. Posaconazole was concurrently administered with proton pump inhibitor in ≥ 90% of patients. The median (IQR) of initial posaconazole Cmin following 300 mg daily of posaconazole tablet was significantly higher than that of 800 mg daily of posaconazole suspension [1.65 (0.97-2.13) mg/L versus 0.81 (0.48-1.15) mg/L, P < 0.01]. Variability in posaconazole Cmin was apparent regardless of the formulations prescribed and dose adjustments were routinely undertaken to maintain therapeutic Cmin. A clear dose-response relationship was observed in patients receiving posaconazole MR tablets. Non-specific adverse events (fatigue, tremor, lethargy, sweating, nausea/vomiting and weight loss) were reported in 3/78 (4%) patients receiving posaconazole MR tablets. Posaconazole Cmin in these three patients was determined to be 9.6, 6.2 and 2.3 mg/L.

Conclusions

The current study has provided clinically important insights into the TDM of posaconazole in LTx recipients. Routine TDM should be undertaken in LTx recipients receiving posaconazole suspension and/or MR tablets.

Inflammation is a potential risk factor of voriconazole overdose in hematological patients

Voriconazole (VRC) overdoses are frequent and expose patients at high risk of adverse effects. This case-control study performed in hematological patients who benefited from VRC therapeutic drug monitoring from January 2012 to December 2015 aimed to identify risk factors of VRC overdose. Pharmacogenetic, biological, and demographic parameters at the time of VRC trough concentration (C_min ) were retrospectively collected from medical records. Cases (VRC overdose: defined by a VRC C_min ≥ 4 mg/L; n = 31) were compared to controls (no VRC overdose: defined by VRC C_min < 4 mg/L; n = 31) using nonparametric or chi-square tests followed by multivariable analysis. VRC overdoses were significantly associated with high CRP and bilirubin levels, intravenous administration, and age in univariable analysis. In contrast, the proportion of CYP genotypes (CYP2C19, CYP3A4, or CYP3A5, considered alone or combined in a combined genetic score) were not significantly different between patients who experienced a VRC overdose and those who did not. In multivariable analysis, the class of CRP level (defined by median CRP levels of 96 mg/L) was the sole independent risk factor of VRC overdose (P < 0.01). Patients with CRP levels > 96 mg/L) had a 27-fold (IC 95%: [6-106]) higher risk of VRC overdose than patients with CRP levels ≤ 96 mg/L. This study demonstrates that inflammatory status, assessed by CRP levels, is the main risk factor of VRC overdose in French hematological patients, whereas pharmacogenetic determinants do not appear to be involved.

Posaconazole Tablets in Real-Life Lung Transplantation: Impact on Exposure, Drug-Drug Interactions, and Drug Management in Lung Transplant Patients, Including Those with Cystic Fibrosis

Appropriate exposure to posaconazole (PSZ) has been limited until the recent approval of the delayed-release oral tablet formulation. Our goal was to determine the exposure obtained by using the standard dose of 300 mg once a day in lung transplant (LT) patients, including patients with cystic fibrosis (CF). PSZ trough concentrations (C0) were determined using a liquid chromatography-tandem mass spectrometry assay. Indicative thresholds of interest were <0.7 mg/liter for prophylaxis and 1 to 3 mg/liter for cure. The tacrolimus (TRL) and everolimus (ERL) C0 measured during PSZ exposure were also collected. The interaction with proton-pump inhibitors (PPI) was evaluated. We recorded the results for 21 CF patients with LT (CFLT patients), 11 non-CF patients with LT (NCFLT patients), and 27 nontransplant (NT) patients in pneumology departments. The weights of the NCFLT, CFLT, and NT patients were 59.2 ± 8.4, 48.8 ± 8.4, and 63.7 ± 16.6 kg, respectively (P = 0.001* [asterisk means that statistical test is significant]), and the PSZ C0 exposures for these patients were 1.9 ± 1.5, 1.1 ± 0.8, and 2.4 ± 1.8 mg/liter, respectively (P < 0.00001*). More than 60% of the concentrations were in the therapeutic range. In CFLT patients, the administration of one 300-mg PSZ tablet quickly achieved an exposure similar to that achieved with the PSZ oral suspension formulation (OSF) administered 3 or 4 times a day for several months. The TRL C0/dose ratio (C0/D) was 7.4 ± 4.4 mg/liter with PSZ tablets, whereas it was 4.6 ± 0.8 mg/liter with the PSZ oral solution (P = 0.034*). The ERL C0/D was similar with both formulations. PPI had no impact on the PSZ concentration (1.49 ± 1.07 mg/liter without PPI versus 1.33 ± 1.17 mg/liter with PPI; P = 0.4134*). Despite the high levels of exposure, PSZ remained well tolerated (one case of diarrhea and one case of fatigue were reported). PSZ tablet administration allows satisfactory exposure, even in CFLT patients, with a dosage lower than that of the PSZ OSF. This once-a-day formulation was not impacted by PPI, which are extensively used in CF patients.

Safety study and therapeutic drug monitoring of the oral tablet formulation of posaconazole in patients with haematological malignancies

PURPOSE

Posaconazole is a triazole antifungal widely used for prophylaxis of invasive fungal disease (IFI). Posaconazole tablets allow reaching higher plasma levels than the oral suspension, but safety data with this formulation in real life are scarce. This study aimed at evaluating the safety profile, the pharmacokinetic variability, and the concentration-toxicity relationship of posaconazole tablets in patients with haematological malignancies.

METHODS

Sixty neutropenic patients treated with posaconazole tablets for prophylaxis of IFI were prospectively included in the study. Adverse drug reactions (ADR) were recorded and analyzed by the Regional Pharmacovigilance Centre to assess posaconazole implication. Blood samples were drawn once a week and plasma trough concentrations (C _min) were assayed by LC-MS/MS. The rates of ADR by quartile of C _min were compared.

RESULTS

Eighteen patients (30%) experienced at least one ADR attributed to posaconazole. Liver function test (LFT) abnormalities were encountered in 20% of patients and resulted in four (6.7%) treatment discontinuations. Posaconazole median (range) C _min was 1.36 (< 0.1-3.44) µg/mL (inter-patient CV = 43.9%). During follow-up, 28.6% of patients had at least one concentration < 0.7 µg/mL, and 35.7% had at least one concentration > 2 µg/mL. Rates of ADR by quartile of C _min were not different.

CONCLUSIONS

Posaconazole was well tolerated; however, LFT abnormalities were frequent. ADR occurrence was not linked to posaconazole exposure. Because posaconazole concentrations were highly variable, TDM can be helpful to avoid underexposure to the drug and increase its efficacy in preventing IFI. Conversely, a large proportion of patients was overexposed and might have benefited of a dose reduction.