Risk factors for subtherapeutic levels of posaconazole tablet

Real-world Experience of Posaconazole Therapeutic Drug Monitoring in Oncology Patients: Clinical Implications of Hypoalbuminemia as a Predictor of Subtherapeutic Posaconazole Levels

Background

Posaconazole maintains broad antifungal activity and is employed for prevention and treatment of invasive fungal infections in oncology patients. Older formulations required therapeutic drug monitoring, and specific plasma drug levels have been recommended. This study evaluated factors associated with subtherapeutic concentrations with the newer delayed-release tablet formulation.

Methods

In this retrospective, single-center cohort study at a national comprehensive cancer center, all oncology patients receiving delayed-release posaconazole at standard dosing of 300 mg orally per day from 06/2021 to 07/2023 with plasma drug concentration evaluation were identified. Demographic, clinical, and laboratory data were evaluated to identify risk factors associated with subtherapeutic drug levels at targets of ≥1.25 µg/mL and ≥1.8 µg/mL.

Results

Of 110 patients identified, 98 met criteria for inclusion in the study. The median time from initiation of posaconazole to drug level assessment was 13 days, and the median concentration was 1.29 µg/mL. Of the 22 patients receiving posaconazole for prophylaxis, 5 (22.7%) failed to achieve concentrations ≥0.7 µg/mL, and of 76 patients receiving posaconazole for treatment, 38 (50%) failed to achieve concentrations of ≥1.25 µg/mL. In multivariable analysis, albumin of ≤3 g/dL and ideal body weight ≥60 kg were found to be associated with subtherapeutic levels. For a higher target of ≥1.8 µg/mL, only albumin ≤3 g/dL was associated with subtherapeutic levels for the variables evaluated.

Conclusions

A higher initial dosing strategy and therapeutic drug monitoring for oncology patients with albumin ≤3 g/dL receiving posaconazole, particularly for the treatment of invasive fungal infection, could be considered.

Factors Influencing Serum Posaconazole Concentrations in Patients with Hematologic Malignancies Receiving Delayed-Release Tablets

BACKGROUND

Posaconazole (PCZ) plays a crucial role in the prophylaxis and treatment of invasive fungal infections in hematologic malignancies. PCZ concentrations reportedly vary among patients receiving delayed-release tablets (DRT). However, the factors influencing these concentrations remain insufficiently elucidated. Therefore, this study aimed to evaluate the factors influencing PCZ concentrations and their effect on the probability of target attainment (PTA) using a population pharmacokinetic (PPK) approach. We also explored the relationship between PCZ exposure and hepatotoxicity.

METHODS

This retrospective study included adult patients with hematologic malignancies who received PCZ DRT. A PPK model was developed based on observational data for 130 concentrations in 28 patients. Simulation analyses were performed to assess the PTA at standard doses of 0.7 and 1.0 mg/L for prophylaxis and treatment, respectively. Estimated concentrations were used to evaluate the correlation between PCZ exposure and hepatotoxicity.

RESULTS

Significant factors influencing PCZ concentrations included body weight, serum total protein levels, and diarrhea. Diarrhea correlated with decreased PCZ concentrations resulting in up to 26% lower PTA compared with that without diarrhea. Moreover, PTA declined markedly as the total protein levels decreased from 6.6 g/dL to 4.4 g/dL. The incidence of hepatotoxicity was 17.4% (4/23); no significant relationship could be established between the PCZ concentrations and hepatotoxicity (P = 0.188).

CONCLUSIONS

We identified the factors affecting PCZ exposure, which could not be detected by PPK analysis using data from clinical trials. Our results suggest that the generally recommended dose of PCZ causes underexposure in patients with hematologic malignancies characterized by high body weight, hypoproteinemia, or concurrent diarrhea. Therapeutic drug monitoring for DRT may be recommended, especially in patients with these risk factors.

Utility of triazole antifungal therapeutic drug monitoring: Insights from the Society of Infectious Diseases Pharmacists: Endorsed by the Mycoses Study Group Education and Research Consortium

Triazole antifungals (i.e., fluconazole, itraconazole, voriconazole, posaconazole, and isavuconazole) are commonly used in clinical practice to prevent or treat invasive fungal infections. Most triazole antifungals require therapeutic drug monitoring (TDM) due to highly variable pharmacokinetics, known drug interactions, and established relationships between exposure and response. On behalf of the Society of Infectious Diseases Pharmacists (SIDP), this insight describes the pharmacokinetic principles and pharmacodynamic targets of commonly used triazole antifungals and provides the rationale for utility of TDM within each agent.

Primary prophylaxis of invasive fungal diseases in patients with haematological malignancies: 2022 update of the recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society for Haematology and Medical Oncology (DGHO)

Patients with haematological malignancies (HM) are at high risk of developing invasive fungal disease (IFD) with high morbidity and attributable mortality. We reviewed data published until September 2021 to update the 2017 antifungal prophylaxis recommendations of the German Society of Haematology and Medical Oncology (DGHO). The strong recommendation to administer antifungal prophylaxis in patients with HM with long-lasting neutropenia, i.e. <500 cells/μL for >7 days remains unchanged. Posaconazole remains the drug of choice for mould-active prophylaxis in these patients. Novel treatment options in HM, such as CAR-T-cell treatment or novel targeted therapies for acute myeloid leukaemia (AML) were considered, however, data are insufficient to give general recommendations for routine antifungal prophylaxis in these patients. Major changes regarding specific recommendations compared to the 2017 edition are the now moderate instead of mild support for the recommendations of isavuconazole and voriconazole. Furthermore, published evidence on micafungin allows recommending it at moderate strength for its use in HM. For the first time we included recommendations for non-pharmaceutical measures regarding IFD, comprising the use of high-efficiency particulate air (HEPA) filters, smoking, measures during construction work and neutropenic diets. We reviewed the impact of antifungal prophylaxis with triazoles on drug-drug interactions with novel targeted therapies that are metabolized via cytochrome p450 where triazoles inhibit CYP3A4/5. The working group recommends reducing the dose of venetoclax when used concomitantly with strong CYP3A4 inhibiting antifungals. Furthermore, we reviewed data on the prophylactic use of novel antifungal agents. Currently there is no evidence to support their use in a prophylactic setting in clinical practice.

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.

A Review of Population Pharmacokinetic Models of Posaconazole

Posaconazole is often used for the prophylaxis and treatment of invasive fungal infections (IFI). However, intra- and inter-individual differences and drug interactions affect the efficacy and safety of posaconazole. Precision dosing of posaconazole based on the population pharmacokinetic (PopPK) model may assist in making significant clinical decisions. This review aimed to comprehensively summarize the published PopPK models of posaconazole and analyze covariates that significantly influence posaconazole exposure. Articles published until May 2022 for PopPK analysis of posaconazole were searched in PubMed and EMBASE databases. Demographic characteristics, model characteristics, and results of PopPK analysis were extracted from the selected articles. In addition, the steady-state pharmacokinetic profiles of posaconazole were simulated at different covariate levels and dosing regimens. Out of the 13 studies included in our review, nine studies included adults, three included children, and one included both adults and children. All oral administration models were one-compartment models, and all intravenous administration models were two-compartment models. Body weight, proton pump inhibitors, and incidence of diarrhea were found to be important covariates. Clinically, the potential impact of factors such as patient physiopathologic characteristics and comorbid medications on posaconazole pharmacokinetics should be considered. Dose adjustment in combination with TDM or replacement with a tablet or intravenous formulation with higher exposure may be an effective way to ensure drug efficacy as well as to reduce fungal resistance. Meanwhile, published models require further external evaluation to examine extrapolation.

External evaluation of published population pharmacokinetic models of posaconazole

Population pharmacokinetic (PopPK) models of posaconazole have been established to promote the precision dosing. However, the performance of these models extrapolated to other centers has not been evaluated. This study aimed to conduct an external evaluation of published posaconazole PopPK models to evaluate their predictive performance. Posaconazole PopPK models screened from the PubMed and MEDLINE databases were evaluated using an external dataset of 213 trough concentration samples collected from 97 patients. Their predictive performance was evaluated by prediction-based diagnosis (prediction error), simulation-based diagnosis (visual predictive check), and Bayesian forecasting. In addition, external cohorts with and without proton pump inhibitor were used to evaluate the models respectively. Ten models suitable for the external dataset were finally included into the study. In prediction-based diagnostics, none of the models met pre-determined criteria for predictive indexes. Only M4, M6, and M10 demonstrated favorable simulations in visual predictive check. The prediction performance of M5, M7, M8, and M9 evaluated using the cohort without proton pump inhibitor showed a significant improvement compared to that evaluated using the whole cohort. Consistent with our expectations, Bayesian forecasting significantly improved the predictive per-formance of the models with two or three prior observations. In general, the applicability of these published posaconazole PopPK models extrapolated to our center was unsatisfactory. Prospective studies combined with therapeutic drug monitoring are needed to establish a PopPK model for posaconazole in the Chinese population to promote individualized dosing.

New Perspectives on Antimicrobial Agents: Isavuconazole

Isavuconazole is the newest of the clinically available advanced generation triazole antifungals and is active against a variety of yeasts, molds, and dimorphic fungi. Its current FDA-approved indications include the management of invasive aspergillosis as well as mucormycosis, though the latter indication is supported by limited clinical data. Isavuconazole did not achieve noninferiority to caspofungin for the treatment of invasive candidiasis and therefore lacks an FDA-approved indication for this invasive disease. Significant advantages of isavuconazole, primarily over voriconazole but in some circumstances posaconazole as well, make it an appealing option for the management of complex patients with invasive fungal infections. These potential advantages include lack of QTc interval prolongation, more predictable pharmacokinetics, a less complicated drug interaction profile, and improved tolerability, particularly when compared to voriconazole. This review discusses these topics in addition to addressing the in vitro activity of the compound against a variety of fungi and provides insight into other distinguishing factors among isavuconazole, voriconazole, and posaconazole. The review concludes with an opinion section in which the authors provide the reader with a framework for the current role of isavuconazole in the antifungal armamentarium and where further data are required.

Factors associated with subtherapeutic levels of oral posaconazole tablet- a detailed analysis from a tertiary care center in India

INTRODUCTION

Posaconazole is a broad spectrum triazole antifungal with activity against various clinically important fungi. The delayed release (DR) tablet of posaconazole has been shown to have a superior pharmacokinetic profile in comparison with the oral suspension.

METHODS

We retrospectively analyzed the factors associated with posaconazole levels < 1.25 μg/ml in 164 patients receiving the DR tablet for therapeutic purposes.

RESULTS

Of the 164 patients, 53 (32.3%) showed subtherapeutic trough levels of posaconazole. The use of proton pump inhibitors (PPIs) (95% CI: 1.41 - 3.91; p value = 0.028) and the presence of diarrhea (95% CI: 1.95 - 6.93; p value = 0.001) were significantly associated with subtherapeutic levels. Thirteen of the 21 patients receiving posaconazole tablets via the nasogastric (NG) tube had therapeutic levels.

CONCLUSION

This is the largest study from India analyzing factors associated with subtherapeutic levels of the DR tablet of posaconazole. These findings reinforce the importance of therapeutic drug monitoring. Unlike in previous studies, obesity and hypoalbuminemia were not found to be significant factors in our settings. The use of PPIs and diarrhea remained significant factors as found in previous studies. Administering the DR tablet of posaconazole via the NG tube may be a viable option.

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.

Consensus guidelines for antifungal prophylaxis in haematological malignancy and haemopoietic stem cell transplantation, 2021

Antifungal prophylaxis can reduce morbidity and mortality from invasive fungal disease (IFD). However, its use needs to be optimised and appropriately targeted to patients at highest risk to derive the most benefit. In addition to established risks for IFD, considerable recent progress in the treatment of malignancies has resulted in the development of new 'at-risk' groups. The changing epidemiology of IFD and emergence of drug resistance continue to impact choice of prophylaxis, highlighting the importance of active surveillance and knowledge of local epidemiology. These guidelines aim to highlight emerging risk groups and review the evidence and limitations around new formulations of established agents and new antifungal drugs. It provides recommendations around use and choice of antifungal prophylaxis, discusses the potential impact of the changing epidemiology of IFD and emergence of drug resistance, and future directions for risk stratification to assist optimal management of highly vulnerable patients.

Consensus guidelines for optimising antifungal drug delivery and monitoring to avoid toxicity and improve outcomes in patients with haematological malignancy and haemopoietic stem cell transplant recipients, 2021

Antifungal agents can have complex dosing and the potential for drug interaction, both of which can lead to subtherapeutic antifungal drug concentrations and poorer clinical outcomes for patients with haematological malignancy and haemopoietic stem cell transplant recipients. Antifungal agents can also be associated with significant toxicities when drug concentrations are too high. Suboptimal dosing can be minimised by clinical assessment, laboratory monitoring, avoidance of interacting drugs, and dose modification. Therapeutic drug monitoring (TDM) plays an increasingly important role in antifungal therapy, particularly for antifungal agents that have an established exposure-response relationship with either a narrow therapeutic window, large dose-exposure variability, cytochrome P450 gene polymorphism affecting drug metabolism, the presence of antifungal drug interactions or unexpected toxicity, and/or concerns for non-compliance or inadequate absorption of oral antifungals. These guidelines provide recommendations on antifungal drug monitoring and TDM-guided dosing adjustment for selected antifungal agents, and include suggested resources for identifying and analysing antifungal drug interactions. Recommended competencies for optimal interpretation of antifungal TDM and dose recommendations are also provided.

Effect of High-Dose Posaconazole on Serum Levels in Adult Patients with Hematologic Malignancy

Posaconazole (POS) appears to have dose-proportional pharmacokinetics; however, there is a paucity of real-life data. We retrospectively evaluated 67 patients with hematologic cancer who had POS dose increases from 300 mg/day to either 400 mg/day (n = 52) or 300 mg twice daily (BID) (n = 15) and for whom POS serum levels were measured. Median POS levels were 840 ng/ml, 1,625 ng/ml, and 2,710 ng/ml for the dosages of 300 mg/day, 400 mg/day, and 300 mg BID, respectively. Significant interpatient variability in serum levels was noted.

Choice and duration of antifungal prophylaxis and treatment in high-risk haematology patients

PURPOSE OF REVIEW

This review aims to summarize available guidelines as well as the emerging evidence for the prevention and treatment of invasive fungal diseases in high-risk haematology patients.

RECENT FINDINGS

Primary mould-active prophylaxis is the strategy used in many centres to manage the risk of invasive fungal disease in high-risk haematology patients, and posaconazole remains the antifungal of choice for most of these patients. Data on the use of other antifungals for primary prophylaxis, including isavuconazole, are limited. There is considerable interest in identifying a strategy that would limit the use of mould-active agents to the patients who are the most likely to benefit from them. In this regard, a recent trial demonstrated that the preemptive strategy is noninferior to the empiric strategy. For primary treatment of invasive aspergillosis, two randomized trials found isavuconazole and posaconazole to be noninferior to voriconazole. Isavuconazole does not appear to require therapeutic drug monitoring.

SUMMARY

Prophylaxis and treatment of invasive fungal diseases in high-risk haematology patients is a rapidly evolving field. Critical clinical questions remain unanswered, especially regarding the management of suspected invasive fungal diseases breaking through mould-active prophylaxis, and the duration of antifungal therapy for invasive mould infections.

Managing uncertainty in antifungal dosing: antibiograms, therapeutic drug monitoring and drug-drug interactions

PURPOSE OF REVIEW

A number of pharmacokinetic and pharmacodynamic factors in critically ill or severely immunosuppressed patients influence the effectiveness of antifungal therapy making dosing less certain. Recent position papers from infectious diseases societies and working groups have proposed methods for dosage individualization of antibiotics in critically ill patients using a combination of population pharmacokinetic models, Monte-Carlo simulation and therapeutic drug monitoring (TDM) to guide dosing. In this review, we examine the current limitations and practical issues of adapting a pharmacometrics-guided dosing approaches to dosing of antifungals in critically ill or severely immunosuppressed populations.

RECENT FINDINGS

We review the current status of antifungal susceptibility testing and challenges in incorporating TDM into Bayesian dose prediction models. We also discuss issues facing pharmacometrics dosage adjustment of newer targeted chemotherapies that exhibit severe pharmacokinetic drug-drug interactions with triazole antifungals.

SUMMARY

Although knowledge of antifungal pharmacokinetic/pharmacodynamic is maturing, the practical application of these concepts towards point-of-care dosage individualization is still limited. User-friendly pharmacometric models are needed to improve the utility of TDM and management of a growing number of severe pharmacokinetic antifungal drug-drug interactions with targeted chemotherapies.

Subtherapeutic posaconazole prophylaxis in a gastric bypass patient following hematopoietic stem cell transplantation

PURPOSE

A case of invasive fungal infections (IFIs) with subtherapeutic posaconazole prophylaxis in a gastric bypass patient following hematopoietic stem cell transplantation (HSCT) is reported.

SUMMARY

A 52-year-old malnourished male with a medical history of Roux-en-Y gastric bypass for obesity developed acute myelogenous leukemia and underwent allogeneic HSCT approximately 17 months later. He was admitted 1 month after HSCT for failure to thrive and initiated on parenteral nutrition due to worsening diarrhea and suspected gastrointestinal graft-versus-host disease (GI GVHD). During admission, the patient was continued on daily oral posaconazole for antifungal prophylaxis and was found to have subtherapeutic posaconazole and deficient vitamin levels, likely secondary to his gastrojejunostomy and increased gastric transit time. The oral posaconazole was altered to twice-daily dosing in an effort to increase serum drug levels and prevent IFIs.

CONCLUSION

Patients with a history of gastric bypass are at increased risk for malabsorption of oral posaconazole and nutrients, especially following HSCT with suspected GI GVHD.

Mucormycosis

Mucormycosis is a rare but aggressive fungal disease that mainly affects patients with poorly controlled diabetes mellitus and those who are severely immunocompromised, including patients with hematological malignancies and solid organ transplant recipients. Early recognition of infection is critical for treatment success, followed by prompt initiation of antifungal therapy with lipid formulation amphotericin B. Posaconazole and isavuconazole should be used for stepdown and salvage therapy. Surgical debridement is key for tissue diagnosis and treatment and should be pursued urgently whenever possible. In addition to surgery and antifungal therapy, reverting the underlying risk factor for infection is important for treatment response.

Clinical and Pharmacological Considerations for Concomitant Administration of Posaconazole and Isavuconazole with Letermovir

We sought in this case-control retrospective study to compare posaconazole and isavuconazole (PCZ and IVC, respectively) plasma trough concentration (C _trough) levels in high-risk allogeneic hematopoietic cell transplant (HCT) recipients who received letermovir (LET) or not. PCZ/IVC C _trough levels were not found to be significantly different between cases and controls, as they were 1.31 mg/liter (median) (interquartile range [IQR], 0.90) versus 1.36 mg/liter (IQR, 1.16) (P = 0.31) and 3.20 mg/liter (IQR, 2.40) versus 2.35 mg/liter (IQR, 1.50) (P = 0.17), respectively. In conclusion, we observed PCZ/IVC C _trough levels within the expected range and no significant effect of LET coadministration.

Antifungal therapy with azoles and the syndrome of acquired mineralocorticoid excess

The syndromes of mineralocorticoid excess describe a heterogeneous group of clinical manifestations leading to endocrine hypertension, typically either through direct activation of mineralocorticoid receptors or indirectly by impaired pre-receptor enzymatic regulation or through disturbed renal sodium homeostasis. The phenotypes of these disorders can be caused by inherited gene variants and somatic mutations or may be acquired upon exposures to exogenous substances. Regarding the latter, the symptoms of an acquired mineralocorticoid excess have been reported during treatment with azole antifungal drugs. The current review describes the occurrence of mineralocorticoid excess particularly during the therapy with posaconazole and itraconazole, addresses the underlying mechanisms as well as inter- and intra-individual differences, and proposes a therapeutic drug monitoring strategy for these two azole antifungals. Moreover, other therapeutically used azole antifungals and ongoing efforts to avoid adverse mineralocorticoid effects of azole compounds are shortly discussed.

Nanocomposite systems for precise oral delivery of drugs and biologics

Oral delivery is considered the favoured route of administration for both local and systemic delivery of active molecules. Formulation of drugs in conventional systems and nanoparticles has provided opportunities for targeting the gastrointestinal (GI) tract, increasing drug solubility and bioavailability. Despite the achievements of these delivery approaches, the development of a product with the ability of delivering drug molecules at a specific site and according to patients' needs remains a challenging endeavour. The complexity of the physicochemical properties of colloidal systems, their stability in different regions of the gastrointestinal tract, and interaction with the restrictive biological barriers hampered their success for oral precise medicine. To overcome these issues, nanoparticles have been combined with polymers to create hybrid nanosystems, namely nanocomposites. They offer enormous possibilities of structural and mechanical modifications to both nanoparticles and polymeric matrixes to generate systems with new properties, functions, and applications for oral delivery. In this review, nanocomposites' physicochemical and functional properties intended to target specific regions of the GI tract-oral cavity, stomach, small bowel, and colon-are analysed. In parallel, it is provided an insight in the nanocomposite solutions for oral delivery intended for systemic and local absorption, together with a focus on inflammatory bowel diseases (IBDs). Additional difficulties in managing IBD related to the alteration in the physiology of the intestine are described. Finally, future perspectives and opportunities for advancement in this field are discussed.

Clinical considerations on posaconazole administration and therapeutic drug monitoring in allogeneic hematopoietic cell transplant recipients

There is a paucity of data on posaconazole (PCZ) dosing and therapeutic-drug-monitoring (TDM) in allogeneic hematopoietic cell transplant recipients (allogeneic-HCTr). This was a 3-year retrospective multicenter study (January 1, 2016 to December 31, 2018) in adult allogeneic-HCTr who received PCZ (intravenously, IV and/or as delayed-release tablet, DRT) as prophylaxis or treatment for ≥7 consecutive days (D) with at least 1-PCZ-level available using data of the Swiss Transplant Cohort Study. The primary objective was to describe the distribution of PCZ-level and identify predictors of therapeutic PCZ-level and associations between PCZ-dosing and PCZ-level. A total of 288 patients were included: 194 (67.4%) and 94 (32.6%) received PCZ as prophylaxis and treatment, respectively, for a median of 90 days (interquartile range, IQR: 42-188.5). There were 1944 PCZ-level measurements performed, with a median PCZ level of 1.3 mg/L (IQR: 0.8-1.96). PCZ-level was <0.7 mg/L in 383/1944 (19.7%) and <1.0 mg/L in 656/1944 (33.7%) samples. PCZ-level was <0.7 mg/L in 260/1317 (19.7%) and <1.0 mg/L in 197/627 (31.4%) in patients who received PCZ-prophylaxis versus treatment, respectively. There were no significant differences in liver function tests between baseline and end-of-treatment. There were nine (3.1%) breakthrough invasive fungal infections (bIFI), with no difference in PCZ levels between patients with or without bIFI. Despite a very intensive PCZ-TDM, PCZ-levels remain below target levels in up to one-third of allogeneic-HCTr. Considering the low incidence of bIFI observed among patients with PCZ levels in the targeted range, our data challenge the clinical utility of routine universal PCZ-TDM.

Initial posaconazole dosing to achieve therapeutic serum posaconazole concentrations among children, adolescents, and young adults receiving delayed-release tablet and intravenous posaconazole

Posaconazole is a broad-spectrum antifungal used for prophylaxis and treatment of invasive fungal diseases. There are limited data on the optimal dosing, safety, and efficacy of the DRT and IV formulations in immunocompromised pediatric and adolescent patients. We describe our experience including dosing, plasma trough concentrations, safety, and tolerability. Plasma concentrations ≥.7 µg/mL were considered therapeutic for prophylaxis and ≥1.0 µg/mL for treatment. Fifty-four patients (median age of 16 years) received DRT or IV formulations of posaconazole. Thirty-one (57%) patients received posaconazole for treatment and 23 (43%) for prophylaxis. Overall, 36 (67%) patients achieved targeted initial plasma trough concentrations (median 1.3 µg/mL) (Figure 1). The median daily dose among patients <13 years of age who achieved the targeted initial concentrations was 7.3 mg/kg/day for the DRT formulation and 9.8 mg/kg/day for the IV formulation. The median daily dose among patients ≥13 years of age who achieved the targeted initial concentrations was 4.9 mg/kg/day for the DRT formulation and 5.6 mg/kg/day for the IV formulation. Thirty-six patients (67%) developed transaminitis, mostly grade 1. Our observations show that DRT and IV formulations are safe and effective in immunocompromised children, adolescents, and young adults. Higher dosing per body weight of DRT and IV posaconazole may be required in patients <13 years of age compared with patients 13 years of age and older to achieve therapeutic plasma concentrations. [Figure: see text].

Therapeutic drug monitoring and adverse events of delayed-release posaconazole tablets in patients with chronic pulmonary aspergillosis

BACKGROUND

Posaconazole delayed-release tablets offer better bioavailability than the liquid suspension, but no post-marketing data are available in immunocompetent hosts such as those with chronic pulmonary aspergillosis (CPA).

OBJECTIVES

To explore the pharmacokinetics and adverse event (AE) profile of posaconazole tablets in patients with CPA.

METHODS

Patients started on posaconazole tablets at the National Aspergillosis Centre (NAC), Manchester, UK between February 2014 and October 2015 were identified from the NAC database and analysed retrospectively. The medical records were reviewed for factors that could affect posaconazole serum levels and the development of AEs.

RESULTS

Seventy-two patients were included; 50 (69%) were male and the mean age was 48.5 ± 12 years. Therapeutic levels (≥1 mg/L) were achieved in 90% of cases on 200 mg versus 90% of cases on 300 mg daily (P = not significant). Based on multivariate analysis, female sex (P = 0.041), a 100 mg daily dose (P < 0.001), asthma (P = 0.01) and bronchiectasis (P = 0.001) were associated with subtherapeutic levels. Forty-nine (68%) patients developed AEs, mainly fatigue (37%), dyspnoea (18%) and nausea (12%). AEs were present on 115/196 (59%) occasions on 300 mg/day and on 45/115 (39%) occasions on 200 mg/day (P < 0.01). The mean level was 1.81 ± 0.96 mg/L for patients reporting no AEs and 1.90 ± 1.11 mg/L for those reporting AEs (P = not significant). Factors associated with AEs of grade ≥2 were a daily dose of 300 versus 200 mg (P = 0.001) and asthma (P = 0.008).

CONCLUSIONS

A lower-than-recommended posaconazole tablet dose achieved therapeutic levels in most patients and was better tolerated. Males were more likely to achieve a therapeutic level. Underlying conditions affected the degree and frequency of AEs.

Treatment of invasive fungal diseases in cancer patients-Revised 2019 Recommendations of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Oncology (DGHO)

BACKGROUND

Invasive fungal diseases remain a major cause of morbidity and mortality in cancer patients undergoing intensive cytotoxic therapy. The choice of the most appropriate antifungal treatment (AFT) depends on the fungal species suspected or identified, the patient's risk factors (eg length and depth of granulocytopenia) and the expected side effects.

OBJECTIVES

Since the last edition of recommendations for 'Treatment of invasive fungal infections in cancer patients' of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO) in 2013, treatment strategies were gradually moving away from solely empirical therapy of presumed or possible invasive fungal diseases (IFDs) towards pre-emptive therapy of probable IFD.

METHODS

The guideline was prepared by German clinical experts for infections in cancer patients in a stepwise consensus process. MEDLINE was systematically searched for English-language publications from January 1975 up to September 2019 using the key terms such as 'invasive fungal infection' and/or 'invasive fungal disease' and at least one of the following: antifungal agents, cancer, haematological malignancy, antifungal therapy, neutropenia, granulocytopenia, mycoses, aspergillosis, candidosis and mucormycosis.

RESULTS

AFT of IFDs in cancer patients may include not only antifungal agents but also non-pharmacologic treatment. In addition, the armamentarium of antifungals for treatment of IFDs has been broadened (eg licensing of isavuconazole). Additional antifungals are currently under investigation or in clinical trials.

CONCLUSIONS

Here, updated recommendations for the treatment of proven or probable IFDs are given. All recommendations including the levels of evidence are summarised in tables to give the reader rapid access to key information.

Efficacy of Posaconazole Prophylaxis for Fungal Disease in Hematology Patients Treated With Chemotherapy and Transplantation: An Open-Label, Prospective, Observational Study

Background

Posaconazole (PCZ) is used prophylactically to prevent invasive fungal infections (IFIs) in patients with hematological malignancies.

Objective

To evaluate the cut-off serum concentration of PCZ for successful IFI prophylaxis in Chinese subjects.

Patients and Methods

A total of 74 patients treated with induction chemotherapy (n = 10) and allogeneic hematopoietic stem cell transplantation (HSCT) (n = 64), who received PCZ prophylactically as an oral suspension for >7 days, were included in the study. Clinical, radiological, microbiological culture results, and treatment responses were analyzed and drug concentration assays performed.

Results

The overall incidence of possible, probable, and proven IFIs was 13.5% (10/74), with five patients in the chemotherapy group and five in the HSCT group. The PCZ serum concentration in most patients (54/63) was in the range of 0.25–1.0 μg/ml, and this concentration range was significantly associated with the success rate of PCZ prophylaxis. A cut-off value of 0.47 μg/ml can be considered as an evaluation index for PCZ prophylaxis. Taking a proton pump inhibitor (PPI) would reduce the PCZ blood concentration, but not affect the IFD breakthrough point. PCZ treatment for hematopoietic malignancy or HSCT patients with a serum concentration of PCZ < 0.47 μg/ml were risk factors for PCZ prophylaxis of IFIs, determined by univariable and multivariable regression analyses.

Conclusion

The serum concentration of PCZ was related to the incidence of IFIs and a serum concentration of >0.47 μg/ml is highly recommended to avoid IFIs after chemotherapy or HSCT.

Clinical Trial Registration

Chinese Clinical Trial Registry: ChiCTR1900026294.

Evaluation of posaconazole plasma concentrations achieved with the delayed-release tablets in Korean high-risk patients with haematologic malignancy

BACKGROUND

Posaconazole (PCZ) is a triazole approved for prophylaxis of invasive fungal infections.

OBJECTIVES

Herein, the impact of clinical variables on PCZ plasma concentrations (PPCs) attained with PCZ delayed-release tablet (DRT) was investigated and compared with a historical cohort treated with PCZ oral suspension (OS).

PATIENTS/METHODS

Steady-state PCZ PPCs in 513 patients with haematologic malignancy treated with PCZ-DRT were assessed and impact of variables were analysed. Also, a comparison with matched historical cohort treated with PCZ-OS was made.

RESULTS

The median PPC in the PCZ-DRT group was 1,308.9 ng/mL (range: 29.8-10 455.9). Use of proton pump inhibitor (1181 vs 1344 ng/mL, P = .0337) in the AML/myelodysplastic syndrome remission induction group, diarrhoea (867 vs 1543 ng/mL, P = .0325) and gastrointestinal graft-versus-host disease (870 vs 1713 ng/mL, P = .0178) in the HSCT group were associated with lower PPCs. There was lack of evidence that hepatotoxicity was related with PCZ-DRT. Higher prevalence of UGT1A4*3 allele (33.0%) was noted compared to allele frequency in Koreans in those with PPCs < 500 mg/mL. The median PPC in the PCZ-DRT group was significantly higher than that in the PCZ-OS group (1308.9 vs 713.0 ng/mL, P < .0001). Significantly less patients had PPCs < 700 ng/mL in the PCZ-DRT group compared to the PCZ-OS group (18.7% vs 48.0%, P < .0001).

CONCLUSIONS

Our study demonstrates that PCZ-DRT has enhanced absorption and bioavailability than PCZ-OS in real-world clinical settings. In addition, specific factors associated with lower PPCs should prompt consideration of therapeutic drug monitoring in patients treated with PCZ-DRT.

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.

Using State Transition Models to Explore How the Prevalence of Subtherapeutic Posaconazole Exposures Impacts the Clinical Utility of Therapeutic Drug Monitoring for Posaconazole Tablets and Oral Suspension

Therapeutic drug monitoring (TDM) has been recommended in guidelines for patients receiving posaconazole oral suspension, but its utility in patients receiving posaconazole tablet, which has an improved bioavailability, remains unclear. We used state transition models with first-order Monte Carlo microsimulation to re-examine the posaconazole exposure-response relationships reported in two Phase III clinical trials (prophylaxis with posaconazole oral suspension - Models 1 & 2) and a third multicenter observational TDM study (Model 3). We simulated the impact of TDM-guided interventions to improve initial average posaconazole concentrations (C_avg) to reduce clinical failure (in Models 1 & 2) and breakthrough invasive fungal disease (bIFD) in Model 3. Simulations were then repeated using posaconazole tablet C_avg distributions in place of the oral suspension formulation. In all three models with posaconazole oral suspension, TDM interventions associated with maximal improvement in posaconazole C_avg reduced absolute rates of subtherapeutic exposures (C_avg < 700 ng/mL) by 25-49%. Predicted reductions in absolute clinical failure rates were 11% in Model 1 and 6.5% in Model 2, and a 12.6% reduction in bIFD in Model 3. With the tablet formulation, maximally-effective TDM interventions reduced subtherapeutic exposures by approximately 5% in all three models and absolute clinical failure rates by 3.9% in Model 1, and 1.6% in Model 2; and a 1.6% reduction in bIFD in Model 3. Our modeling suggests that routine TDM during prophylaxis with posaconazole tablets may have limited clinical utility unless populations with higher prevalence (>10%) of subtherapeutic exposures can be identified based on clinical risk factors.

Candida infections in solid organ transplantation: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the American Society of Transplantation Infectious Diseases Community of Practice provide recommendations for the diagnosis and management of Candida infections in solid organ transplant recipients. Candida infections manifest primarily as candidemia and invasive candidiasis and cause considerable morbidity and mortality. Early diagnosis and initiation of treatment are necessary to reduce mortality. For both candidemia and invasive candidiasis, an echinocandin is recommended for initial therapy. However, early transition to oral therapy is encouraged when patients are stable and the organism is susceptible. Candida prophylaxis should be targeted for high-risk patients in liver, small bowel, and pancreas transplant recipients. Future research should address which patient groups may benefit most from preventative antifungal therapy strategies.

Auditing fungal disease in leukemia patients in a tertiary care center: opportunities and challenges for an antifungal stewardship program

Invasive fungal disease (IFD) is responsible for significant morbidity and mortality in patients with acute leukemia. Antifungal stewardship (AFS) programs are utilized in this patient group but have been infrequently evaluated in clinical practice. Adults diagnosed with acute leukemia at an Australian tertiary center over two years were identified, with subsequent auditing of IFD prophylaxis and treatment, and identification of further opportunities for AFS activities. Proven or probable IFD occurred in 6% of cases, including 14% of acute lymphoblastic leukemia (ALL) patients and 6% of acute myeloid leukemia (AML) patients. Mold-active antifungal prophylaxis was used in 84% of cases overall, including in 94% of AML cases and 23% of ALL cases. Local auditing identified target areas for AFS in this complex patient cohort, including modification of clinical guidelines, enhanced patient screening, improved access to fungal diagnostics and therapeutic drug monitoring, and the establishment of a specialized, embedded AFS program.

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.

Co-administration of proton pump inhibitors and/or of steroids may be a risk factor for low trough concentrations of posaconazole delayed-released tablets in adult patients with haematological malignancies

AIMS

The aim of this study was to determine clinical variables associated with posaconazole exposure among adult patients with haematological malignancies who received posaconazole tablets for prophylaxis of invasive fungal infections (IFIs).

METHODS

The study population included adult patients with haematological malignancies who received posaconazole delayed-release tablets for prophylaxis of IFIs after induction chemotherapy for acute leukaemia or graft-versus-host-disease (GVHD) complicating hematopoietic stem cell transplantation (HSCT) in the period January 2016-December 2017.

RESULTS

Sixty-six consecutive patients with 176 posaconazole C_min were included for evaluation in the study. Subtherapeutic posaconazole concentrations (< 0.7 mg l^-1 ) were observed at least once in 33.3% of patients (22/66), and overall in 17.0% of therapeutic drug monitoring (TDM) episodes (30/176). At multilevel linear regression, use of PPIs (P = 0.008), use of intermediate or high dose steroids (>0.7 mg kg^-1 daily) (P = 0.022) and male gender (P = 0.025) were significantly associated with decreased C_min , whereas time from starting therapy (P = 0.032) was associated with increased C_min in our patient population.

CONCLUSION

Posaconazole exposure during treatment with delayed-released tablet formulation may be affected by the use of PPIs and/or of intermediate or high dose steroids.