Exposure-Response Relationship of Posaconazole Suspension in Theprophylaxis of Invasive Fungal Infections in Patients with Acute Myeloid Leukemia

Purpose

Antifungal prophylaxis with posaconazole has demonstrated a reduction in the risk of death due to Invasive fungal infections (IFI)in patients with acute myeloid leukemia (AML) during induction therapy. However, various factors affect the plasma levels of posaconazole and can potentially limit its efficacy. Therapeutic drug monitoring (TDM) can help optimize the dose, but literature is scant from centers with a high IFI burden. This study aimed to evaluate the proportion of de-novo AML patients on induction who could achieve the target level of 700ng/mL with posaconazole prophylaxis,factors that can influence the plasma levels, and the impact of plasma posaconazole levels on incidence of IFI.

Methods

Patients with AML on induction therapy with no baseline IFI were enrolled at our tertiary cancer center which has high prevalence of IFI. These patients received posaconazole suspension as prophylaxis. Daily plasma levels were measured from Day 4 till Day 12 of posaconazole prophylaxis. All patients were monitored for the development of IFI. The data on adverse events, concomitant drugs, mucositis, vomiting, and diarrhea were recorded.

Results

A total of 411 samples from fifty patients were collected. Only 177 out of 411 samples had levels > 700 ng/mL. The median trough level was 610 ng/mL (range30-3000 ng/mL). The median time to achieve target trough concentration was four days (range 4-12 days) from the start of induction.Thirty-eight (76%) patients achieved target plasma levels by day 12 of induction.The median plasma level on day 12 was 690 ng/mL (range,30-1270) in patients who achieved target levels as compared to 340 (50-560) ng/mL in those who did not. Twenty-six (52%) patients had IFI in our study, and the median time to develop breakthrough IFI was 14 days (range 4-24 days). Median and range of plasma levels were 690 ng/ml (30-2410; n = 22) in those who developed IFI, while 590 ng/mL (50-2300 n = 24) in those who did not. The odds of developing IFI in patients who did not achieve the threshold trough concentration of 700 ng/mL was 7.14 (95% CI; 1.35-37.75, p = 0.0206). Occurrence of vomiting (p = 0.02), diarrhea (p = 0.0008), mucositis (p = 0.003) had adverse impact on achievement of target plasma posaconazole levels.

Conclusion

A significant proportion of patients receiving posaconazole prophylaxis fail to achieve target plasma levels which can result in high risk of development of IFI. Occurrence of diarrhea, vomiting and mucositis can adversely affect the achievement target plasma levels.

High prevalence of fluconazole resistant Candida tropicalis among candiduria samples in China: An ignored matter of concern

Introduction

The rapid rise of azole resistance in Candida tropicalis causing invasive infections has become a public health concern; however, the prevalence of resistant isolates in urine samples was not well studied, because the clinical significance of candiduria was not unambiguous due to possible host colonization.

Methods

We performed a 12-year laboratory-based surveillance study of C. tropicalis causing either invasive infection or candiduria and studied their susceptibility profiles to common antifungal drugs. The complete coding domain sequence of the ERG11 gene was amplified in all fluconazole resistant isolates, and aligned with the wild-type sequence to detect nucleotide mutations.

Results

A total of 519 unique C. tropicalis strains isolates, 69.9% of which were isolated from urine samples and remaining 30.1% were invasive strains. Overall, 16.5% isolates were confirmed to be resistant to fluconazole, of which 91.9% were cross-resistant voriconazole. Of note, at the beginning of surveillance (2010-2011), the fluconazole resistance rates were low in both candiduria and invasive groups (6.8% and 5.9%, respectively). However, the resistant rate in the candiduria group significantly increased to 29.5% since 2012-2013 (p = 0.001) and stayed high since then, whilst the resistance rate in the invasive group only showed a gradually increasing trends till 2021 (p > 0.05). Sequence analysis of ERG11 from fluconazole-resistant strains revealed the prevalence of A395T/W mutations were relatively low (16.7%) in the beginning but reached 87.5-100% after 2014. Moreover, the A395W heterozygous mutation isolates became predominant (>60% of resistant strains) after 2016, and indeed isolates carrying corresponding amino acid substitution (Y132F) was highly resistant to fluconazole with MIC₅₀ exceeded 256 μg/ml.

Conclusion

Our study revealed high azole resistant rate in candiduria with its increasing trends observed much earlier than stains causing invasive infections. Given antimicrobial resistance as a critical "One Health" issue, the emergence of antifungal resistance in Candida species that are common commensal colonizers in the human body should be concerned.

Impact of polymorphisms of pharmacokinetics-related genes and the inflammatory response on the metabolism of voriconazole

The effects of inflammatory responses and polymorphisms of the genes encoding cytochrome P450 (CYP) (CYP2C19 and CYP3A5), flavin-containing monooxygenase 3 (FMO3), pregnane X receptor (NR1I2), constitutive androstane receptor (NR1I3), and CYP oxidoreductase (POR) on the ratio of voriconazole (VRCZ) N-oxide to VRCZ (VNO/VRCZ) and steady-state trough concentrations (C0h ) of VRCZ were investigated. A total of 56 blood samples were collected from 36 Japanese patients. Results of multiple linear regression analyses demonstrated that the presence of the extensive metabolizer CYP2C19 genotype, the dose per administration, and the presence of the NR1I2 rs3814057 C/C genotype were independent factors influencing the VNO/VRCZ ratio in patients with CRP levels of less than 40 mg/L (standardized regression coefficients (SRC) = 0.448, -0.301, and 0.390, respectively; all p < .05). With regard to the concentration of VRCZ itself, in addition to the above factors, the presence of the NR1I2 rs7643645 G/G and rs3814055 T/T genotypes were found to be independent factors influencing the VRCZ C0h in these patients (SRC = -0.430, 0.424, -0.326, 0.406 and -0.455, respectively; all p < .05). On the contrary, in patients with CRP levels of at least 40 mg/L, no independent factors were found to affect VNO/VRCZ and VRCZ C0h . Inflammatory responses, and CYP2C19 and NR1I2 polymorphisms may be useful information for the individualization of VRCZ dosages.

Mucormycosis: A triple burden in patients with diabetes during COVID-19 Pandemic

With the upsurge in the cases of COVID-19 around the world, plenty of potential COVID-19 complications are becoming more prevalent, including a higher risk of secondary bacterial and fungal infections. Mucormycosis is one such condition which has high prevalence among individuals with diabetes who were infected with COVID-19.The usage of steroids in the treatment further inflates the risk of infection and exacerbation of disease in pre-existent mucormycosis patients. Generally, Corticosteroid-induced diabetes can arise on long-term steroid medication, increasing the likelihood of mucormycosis. In patients with COVID-19, the indications and dose of corticosteroids should be properly regulated, and persons with diabetes who take insulin or oral anti-diabetic medicines should be cautious. To avoid poor outcomes, strategies to improve glycemic management should be emphasized. This narrative review elucidates different disciplines on rampant use of steroids, iron and zinc supplements as well as the methods utilized as primary or adjunctive treatment of this fatal condition. This article may help to pave the way for robust research that needs to be done to tackle the deadly triple burden of the disease.

Effectiveness and Cost-Effectiveness of Prophylactic Voriconazole and Fluconazole Regarding Prevention of Post-hematopoietic Stem Cell Transplantation Invasive Fungal Infection and Its Related Death: A Single Center Experience

Purpose

Analyzing effectiveness and cost-effectiveness of voriconazole versus fluconazole prophylaxis in hematopoietic stem cell transplantation (HSCT).

Methods

The research included 70 patients; 34 undergoing allogeneic HSCT and 36 undergoing autologous stem cell transplantation (ASCT), alternated to receive either voriconazole or fluconazole prophylaxis for 180 days on a 1:1 basis. Patients were monitored for occurrence of invasive fungal infections (IFI), IFI-related death (IRD) and total death events. Cost-effectiveness of both agents in both groups was also assessed.

Results

Antifungal prophylactic drug had no impact on incidence of IFI and IRD in both allogeneic HSCT and ASCT (P = .452 and P = 1.000; P = .457 and P = .146 respectively). An insignificant difference occurred among patients receiving voriconazole or fluconazole regarding overall survival (OS) and fungal infection-free survival (FFS) in both groups (P = .705 and P = .879; P = .713 and P = .681 respectively). Regarding cost-effectiveness, voriconazole dominated fluconazole regarding prevention of IFI and IRD but was less costly/less effective regarding prevention of total death events and gaining life years in the allogeneic HSCT setting. In the ASCT setting, voriconazole was not cost-effective regarding avoidance of IFI and IRD and was dominated by fluconazole regarding avoidance of total death events and gaining life years.

Conclusions

Voriconazole does not differ from fluconazole regarding its efficacy in prevention of IFI and IRD and does not improve OS and FFS in both allogeneic HSCT and ASCT settings. Voriconazole is cost-effective regarding protection from IFI and IRD in allogeneic HSCT but not cost-effective in ASCT.

Advances in pediatric antimicrobial agents development

PURPOSE OF REVIEW

Rising rates of multidrug-resistant organisms has necessitated the development of novel antimicrobials. In this review, we will highlight agents that have recently received licensure and those that are in clinical development.

RECENT FINDINGS

In recent years, development of novel antimicrobial agents has accelerated. Although most studies have targeted the adult population, studies in pediatric patients are underway. Adequately powered clinical trials are needed to establish the safety and role of these new drugs.

SUMMARY

The recent development of novel antimicrobials to combat multidrug-resistant organisms is encouraging; however, more studies in the pediatric population are needed.

Cost-effectiveness analysis of voriconazole, fluconazole, and amphotericin B for invasive fungal infections following allogeneic hematopoietic stem cell transplantation in Mexico

Background

Patients receiving allogeneic hematopoietic stem cell transplantation (alloHSCT) are at high risk of invasive fungal infections (IFIs), which are associated with high mortality and economic burden. The cost-effectiveness of prophylaxis for the prevention of IFIs in alloHSCT recipients in Mexico has not yet been assessed.

Methods

This analysis modeled a hypothetical cohort of 1,000 patients to estimate costs and outcomes for patients receiving prophylaxis for IFIs following alloHSCT, from the perspective of institutional payers in Mexico. The main prophylaxis agents currently used in Mexican clinical practice are voriconazole, fluconazole, and amphotericin B (AmB). The model accounted for event rates of IFIs during each treatment, assuming IFI causality due to invasive aspergillosis, invasive candidiasis, or other IFIs, and that the outcome for patients during follow-up was IFI-related death, death from other causes, or survival. Clinical efficacies were obtained from published literature; costs were based on local sources. Cost-effectiveness was assessed using incremental cost-effectiveness ratios (ICERs). Univariate (assessing the impact of varying each model parameter) and probabilistic sensitivity analyses were performed.

Results

Voriconazole was associated with the lowest number of breakthrough IFIs, IFI-related deaths, and total number of deaths. Total costs were lower for fluconazole (Mexican pesos [MXN] 72,944; US $4,079) than voriconazole (MXN 101,413; US $5,671) or AmB (MXN 110,529; US $6,180). Voriconazole had better clinical outcomes and lower costs than AmB and could be considered cost-effective compared with fluconazole in line with the local ICER threshold. Drug costs, monitoring costs, and duration of prophylaxis were most sensitive to variation from univariate sensitivity analysis. Findings from the probabilistic sensitivity analysis were consistent with the base-case results.

Conclusion

Voriconazole had the most favorable clinical outcomes, but overall prophylaxis costs were higher than with fluconazole. Overall, based on local ICER thresholds (MXN 184,665; US $10,326), voriconazole was considered a cost-effective option for prophylaxis of IFI in Mexico.

A strategy for designing voriconazole dosage regimens to prevent invasive pulmonary aspergillosis based on a cellular pharmacokinetics/pharmacodynamics model

Background

Invasive pulmonary aspergillosis (IPA) is a life-threatening disease in immunosuppressed patients. Voriconazole is commonly used to prevent and treat IPA in the clinic, but the optimal prophylactic antifungal regimen is unknown. The objective of this study was to clarify the mechanism underlying how voriconazole prevents IPA based on a target cellular pharmacokinetics/pharmacodynamics model, with the aim of identifying a way to design an optimal prophylactic antifungal regimen.

Methods

A nystatin assay was used to establish a target-cells model for A. fumigatus infection. An inhibitory effect sigmoid E_max model was developed to explore the cellular PK/PD breakpoint, and Monte Carlo simulation was used to design the prophylactic antifungal regimen.

Results

The intracellular activity of voriconazole in the target cells varied with its concentration, with the minimum inhibitory concentration (MIC) being an important determinant. For A. fumigatus strains AF293 and AF26, voriconazole decreased the intracellular inoculum by 0.79 and 0.84 lg cfu, respectively. The inhibitory effect sigmoid E_max model showed that 84.01% of the intracellular inoculum was suppressed by voriconazole within 24 h, and that a PK/PD value of 35.53 for the extracellular voriconazole concentration divided by MIC was associated with a 50% suppression of intracellular A. fumigatus. The Monte Carlo simulation results showed that the oral administration of at least 200 mg of voriconazole twice daily was yielded estimated the cumulative fraction of response value of 91.48%. Concentration of voriconazole in the pulmonary epithelial lining fluid and the plasma of > 17.77 and > 1.55 mg/L, respectively, would ensure the PK/PD > 35.53 for voriconazole against most isolates of A. fumigatus and may will be benefit to prevent IPA in clinical applications.

Conclusions

This study used a target cellular pharmacokinetics/pharmacodynamics model to reveal a potential mechanism underlying how voriconazole prevents IPA and has provided a method for designing voriconazole prophylactic antifungal regimen in immunosuppressed patients.

Single-center experience of antifungal prophylaxis for coccidioidomycosis in heart transplant recipients within an endemic area

In endemic regions, coccidioidomycosis causes substantial morbidity and mortality for patients receiving solid organ transplants. We aimed to demonstrate the effect of antifungal coccidioidal prophylaxis in heart transplant (HT) recipients. We retrospectively reviewed the electronic health records of all patients who received HTs between October 19, 2005, and December 13, 2014. We collected information regarding antifungal regimens and determined whether patients subsequently developed infections. Our 174-person cohort all received antifungal prophylaxis for at least 6 months (mean follow-up, 53.8 months). One proven and one probable coccidioidal infection (each, 0.6%) occurred during the study period. The incidence of coccidioidomycosis was 0.6% at 1 year and 2.3% at 5 years. No cases of proven coccidioidomycosis occurred within 2 years after transplantation. No patients developed disseminated disease, and no sentinel events were attributed to coccidioidomycosis. Both fluconazole and voriconazole were well tolerated. In the absence of intolerance or contraindication, we suggest continuing a universal antifungal prophylactic regimen with fluconazole for at least 6-12 months in HT recipients residing in a coccidioidomycosis-endemic area.

Cancer Drug Delivery

Advancements in cancer drug delivery have led to the development of personalized oncology care through molecularly-driven targeted therapies. Understanding molecular and cellular mechanisms which drive tumor progression and resistance is critical in managing new treatment strategies which have shifted from empiric to biomarker-directed therapy selection. Biomarker-directed therapies have improved clinical outcomes in multiple malignancies as monotherapy and in combination with other treatment modalities, however the changing scope of treatment options presents new opportunities and challenges for research. Furthermore, pharmacogenetics may provide a rationale method of personalizing anticancer drug dosing and supportive care management for oncology patients. This chapter reviews biomarker classifications and pharmacogenetics in anticancer therapy and supportive care. Examples of biomarker-directed therapies and clinical assays, in addition to future directions of molecular profiling in oncology therapy management are discussed.

Therapeutic drug monitoring and safety of intravenous voriconazole formulated with sulfobutylether β-cyclodextrin in haematological patients with renal impairment

Because of concerns about accumulation of cyclodextrin, oral voriconazole is recommended for patients with renal impairment. However, intravenous voriconazole may occasionally be imperative in critically ill patients with life-threatening invasive aspergillosis. We investigated the clinical effects of intravenous voriconazole formulated with sulfobutylether β-cyclodextrin (SBECD) in patients with renal impairment. A prospective observational study was conducted on 25 adult patients with haematological malignancies who were treated with intravenous voriconazole for invasive aspergillosis. Among them, seven patients had a baseline creatinine clearance (CrCl) <50 ml min(-1) (case). Although voriconazole trough concentrations were significantly higher in cases (5.84 mg l(-1) ) than controls (2.28 mg l(-1) ), the proportion of concentrations within the target range did not differ between two groups (4/7 and 12/18, respectively; P = 0.658). The frequency of severe adverse events in cases (3/7) was comparable to that of controls (4/18; P = 0.355). No patients showed significant deterioration in renal function after the voriconazole therapy even in patients with renal impairment. Although CrCl <50 ml min(-1) was associated with higher voriconazole concentrations, its clinical impact remains unclear. SBECD-formulated intravenous voriconazole did not lead to a higher incidence of severe adverse events including nephrotoxicity in haematological patients with CrCl <50 ml min(-1) .

Clinical usefulness of therapeutic drug monitoring of voriconazole in a university hospital

INTRODUCTION

The aim of this study was to assess the clinical usefulness of therapeutic drug monitoring (TDM) of voriconazole (VOR) in a university hospital.

METHODS

A retrospective review was conducted on the clinical records of 52 patients treated with VOR and on whom TDM was performed. Steady-state trough plasma VOR concentration was measured at least 5 days after starting treatment. The therapeutic range of plasma VOR concentration was defined as 1-5.5μg/mL.

RESULTS

The most frequent underlying conditions in the study population were lung transplant (48.1%) and hematological malignancies (26.9%). At the first TDM in each patient, VOR levels were outside the therapeutic range in 16 (30.7%) cases: <1μg/mL in 10 (19.2%) and >5.5μg/mL in 6 (11.5%). Eleven patients (21.2%) experienced severe muscle weakness and had considerable difficulty walking. All these patients were receiving concomitant treatment with corticosteroids. Age younger than 30 years (p=.005) and cystic fibrosis as the underlying disease (p=.04) were factors associated with low VOR levels. Almost all patients who had VOR concentrations >1μg/mL at the first TDM had a successful outcome (96%).

CONCLUSIONS

Plasma VOR concentrations were outside the therapeutic range at the first TDM in 30% (16/52) of patients. Age younger than 30 years and cystic fibrosis were factors associated with low VOR levels. The potential interactions between corticosteroids and VOR should be highlighted, as they could be responsible for a high rate of muscle weakness observed in our patients. Prospective trials are needed to investigate VOR TDM and corticosteroid pharmacokinetics.

The role of primary antifungal prophylaxis in patients with haematological malignancies

Invasive fungal infections (IFIs) represent important complications in patients with haematological malignancies. Chemoprevention of IFIs may play an important role in this setting, but in the past decades the majority of antifungal drugs utilized demonstrated poor efficacy, particularly in the prevention of invasive aspergillosis. The new triazoles are very useful antifungal drugs, more suitable for prophylaxis of IFIs than amphotericin B and echinocandins. In this review, the main clinical data about antifungal prophylaxis with fluconazole, itraconazole, voriconazole and posaconazole are analysed. At present, posaconazole appears to be the most efficacious azole in antifungal prophylaxis, particularly in patients with acute myeloid leukaemia.

Antifungal Drugs in the Management of Hematological Diseases in a Home Care Program

Antifungal drugs are frequently used in hematology due to relatively high frequency of infections. Electronic health records of home care patients were retrospectively scanned, looking for antifungal drugs, nystatin, fluconazole, amphotericin B, caspofungin, itraconazole, voriconazole, and posaconazole; we extrapolated frequency, type, indication for use, and duration of each identified antifungal treatment. From September 15, 2011 to September 15, 2012, among 106 patients, median age 83 years, affected by cancer in 82 and other diagnosis in 24 patients, 18 were treated with antifungals, 12 with systemic antifungal (fluconazole 6, itraconazole 5, sequential voriconazole, and itraconazole 1) and 6 with local antifungal. According to our results, the use of antifungals in home care hematological patients is frequent, but limited to certain molecules.

Voriconazole and its clinical potential in the prophylaxis of systemic fungal infection in patients with hematologic malignancies: a perspective review

Invasive fungal infections (IFIs) have become high prevalence in patients with hematologic malignancies. Drug-based strategies for IFIs include various approaches such as prophylactic, empiric, preemptive, and directed treatment. Prophylaxis is an attractive strategy in high-risk patients, given the lack of reliable diagnostics and the high mortality rate associated with IFIs. Prophylaxis includes the use of antifungal drugs in all patients at risk. An ideal antifungal compound for prophylaxis should have a potent and broad activity, be available both orally and intravenously, and have a low toxicity profile. Voriconazole fulfills all these criteria. The clinical efficacy of voriconazole against the majority of fungal pathogens makes it potentially very useful for the prevention of IFIs in patients with hematologic malignancies. Voriconazole appears to be very effective for the primary and secondary prevention of IFIs in these patients and recipients of allogeneic hematopoietic stem-cell transplantation. Randomized controlled trials evaluating voriconazole as primary antifungal prophylaxis in patients with neutropenia treated for a variety of hematologic malignancies have been performed, confirming its value as a prophylactic agent. Voriconazole is generally safe and well tolerated; however, its use is also associated with a number of concerns. In most patients with hematologic malignancies there is the potential for pharmacokinetic drug-drug interactions given that voriconazole is metabolized through the P450 cytochrome system.

Newer antifungal agents

PURPOSE OF REVIEW

In recent years there has been an evolution of a better understanding of the pharmacology and clinical indications of existing antifungal agents and also the development of new broad-spectrum triazoles and a newer class of antifungal agents, the echinocandins. The availability of these agents has broadened the therapeutic options of invasive fungal disease among children and consequently antifungal therapy has become increasingly complex.

RECENT FINDINGS

Adoption of adult guidelines' recommendations has been used to guide pediatric treatment as specific pediatric data were often lacking. This approach has not always selected the most appropriate therapy for newborns or young infants, as the under-dosage of voriconazole based on adult data revealed. Therefore, a detailed understanding of the available antifungal agents in children is crucial for the successful treatment of these serious infections.

SUMMARY

In this review we summarize the main findings regarding antifungal treatment among children that have been recently published, focusing on the pharmacology and pediatric use of newer antifungal agents.