Triazole antifungal agents drug–drug interactions involving hepatic cytochrome P450

Updated antimicrobial dosing recommendations for obese patients

The prevalence of obesity has increased considerably in the last few decades. Pathophysiological changes in obese patients lead to pharmacokinetic (PK) and pharmacodynamic (PD) alterations that can condition the correct exposure to antimicrobials if standard dosages are used. Inadequate dosing in obese patients can lead to toxicity or therapeutic failure. In recent years, additional antimicrobial PK/PD data, extended infusion strategies, and studies in critically ill patients have made it possible to obtain data to provide a better dosage in obese patients. Despite this, it is usually difficult to find information on drug dosing in this population, which is sometimes contradictory. This is a comprehensive review of the dosing of different types of antimicrobials (antibiotics, antifungals, antivirals, and antituberculosis drugs) in obese patients, where the literature on PK and possible dosing strategies in obese adults was critically assessed.

Vincristine Side Effects With Concomitant Fluconazole Use During Induction Chemotherapy in Pediatric Acute Lymphoblastic Leukemia

As a mainstay of treatment for acute lymphoblastic leukemia (ALL), vincristine's side effect profile is well known. Parallel administration of the antifungal fluconazole has been shown to interfere with the metabolism of vincristine, potentially resulting in increased side effects. We conducted a retrospective chart review to determine whether concomitant administration of vincristine and fluconazole during pediatric ALL induction therapy impacted the frequency of vincristine side effects, namely, hyponatremia and peripheral neuropathy. We also evaluated whether the incidence of opportunistic fungal infections was impacted by fluconazole prophylaxis. Medical charts of all pediatric ALL patients treated with induction chemotherapy at Children's Hospital and Medical Center in Omaha, NE, from 2013 to 2021 were retrospectively reviewed. Fluconazole prophylaxis did not significantly impact the rate of fungal infections. We found no correlation between fluconazole use and increased incidence of hyponatremia or peripheral neuropathy, which supports the safety of fungal prophylaxis with fluconazole during pediatric ALL induction therapy.

A possible but unrecognized risk of acceptable daily intake dose triazole pesticides exposure-bile acid disturbance induced pharmacokinetic changes of oral medication

Triazole antifungal pesticides work by inhibiting the activity of lanosterol-14-α-demethylase, a member of cytochrome P450 enzymes (CYPs), but this effect is non-specific. Bile acids (BAs) are important physical surfactants for lipids absorption in intestine, and synthesized by CYPs 7A1/27A1. Thus, we presume that triazole exposure might influence the therapeutic effect or safety of oral medication through disturbing the BAs pool, even though the exposure is under an acceptable daily intake (ADI) dose. Short- and long-term of ADI dose tebuconazole (TEB) exposure animal models were established through various routes, and statins with different hydrophilic and lipophilic properties were gavaged. It exhibited that the activity of CYP7A1/27A1 was indeed inhibited but the expression was up-regulated, the BAs pool was changed either the content and the composition, and the absorption behavior of statins with strong and medium degree of lipid-solubility were significantly changed. A series of experiments performed on models of intestinal mucus, Caco-2 cell monolayer and Caco-2/HT29 co-culture system revealed that the TEB-exposure induced BAs disturbance made impacts on drug absorption in many aspects, including drug solubility and the structure of intestinal barriers. This study suggests us to be more alert about the hazard of pesticides residues for elderly and chronically ill groups.

Hepatotoxicity Induced by Azole Antifungal Agents: A Review Study

Context

Fungal infections are very common, and several medications are used to treat them. Azoles are prescribed widely to treat fungal infections. In addition to therapeutic effects, any drug can be accompanied by side effects in patients. One of the most important complications in this regard is liver injury. Therefore, hepatotoxicity induced by azole antifungal drugs were reviewed in this study.

Evidence Acquisition

English scientific papers were evaluated to review the effects of hepatotoxicity by azole antifungal agents, and the related studies' results were summarized using a table. The systematic search was implemented on electronic databases, including PubMed, Google Scholar, and Science Direct. Original articles and review articles that were published before April 1, 2022, were included in the study. Those articles without available full text or non-English articles were excluded. Also, articles that reported pediatric data were excluded.

Results

Most studies have reported the effects of hepatotoxicity by azole antifungal agents, and their mechanisms have been described.

Conclusions

Clinical evaluations regarding the hepatotoxicity of antifungal agents provided in the literature were reviewed. Therefore, it is recommended to prescribe these drugs with caution in high-risk patients suffering from liver diseases, and patients should be monitored for hepatotoxicity. However, more research is needed to evaluate the hepatotoxicity of azole antifungal agents and select appropriate drugs according to cost-effectiveness and the side effects' profiles, relying on lower incidence of this liver complication.

Pharmacovigilance of triazole antifungal agents: Analysis of the FDA adverse event reporting system (FAERS) database

Triazole antifungal drugs (TAD) are widely used to treat invasive fungal infections due to their broad antifungal spectrum and low toxicity. Despite their preference in the clinic, multiple Adverse Events (AE) are still reported each year.

OBJECTIVE

We aimed to characterize the distribution of Adverse Events associated with Triazole antifungal drugs in different systems and to identify Important Medical Events (IME) signals for Triazole antifungal drugs.

METHODS

The U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) was queried for Adverse Events related to Triazole antifungal drugs from 2012 to 2022. The Adverse Events caused by all other drugs and non-TAD antifungal drugs were analyzed as references. Reporting odds ratio and Bayesian confidence propagation neural network of information components were used to evaluate the association between Triazole antifungal drugs and Important Medical Events. Visual signal spectrum is mapped to identify potential adverse reaction signals.

RESULTS

Overall, 10,262 Adverse Events were reported to be associated with Triazole antifungal drugs, of which 5,563 cases were defined as Important Medical Events. Common adverse drug reactions (ADR) mentioned in the instructions such as delirium and hypokalemia were detected, as well as unlabeled ADRs such as rhabdomyolysis and hepatitis fulminant. Cholestasis, drug-induced liver injury, QT interval prolongation and renal impairment have notable signals in all Triazole antifungal drugs, with 50 percent of patients developing a severe clinical outcome. Isavuconazole had the lowest signal intensity and demonstrated a superior safety profile.

CONCLUSION

Most results are generally consistent with previous studies and are documented in the prescribing instructions, but some IMEs are not included, such as hepatitis fulminant. Additional pharmaco-epidemiological or experimental studies are required to validate the small number of unlabeled ADRs. TAD-related Important Medical Eventshave a considerable potential to cause clinically serious outcomes. Clinical use of Triazole antifungal drugs requires more attention.

Evaluation of the pharmacokinetic effects of itraconazole on alflutinib (AST2818): an open-label, single-center, single-sequence, two-period randomized study in healthy volunteers

Alflutinib (AST2818) is a newly developed third-generation EGFR tyrosine kinase inhibitor for the treatment of lung cancer patients with T790M-resistant mutations. It is metabolized mainly by the CYP3A4 enzyme. At the same time, it has the potential to induce CYP3A4. In this study, we aimed to estimate the effect of itraconazole (a strong inhibitor of CYP3A4) on the pharmacokinetics of alflutinib. For this aim, a single-center, open-label, single-sequence, two-period trial was designed. The pharmacokinetic parameters of AST2818 and its active metabolite AST5902 were established from blood concentration measurements, and adverse events (AEs) of two periods of treatment were documented. For AST2818, the C_max, AUC_0-t, and AUC_0-∞ in period II (coadministration of itraconazole) increased by 6.5 ng/mL, 1263.0 h*ng/mL, and 1067.0 h*ng/mL, respectively. And the corresponding 90% CIs were 1.23 (1.14-1.32), 2.41 (2.29-2.54), and 2.22 (2.11-2.34), respectively. The C_max, AUC_0-t, and AUC_0-∞ of AST5902 in period II decreased by 4.849 ng/mL, 415.60 h*ng/mL, and 391.4 h*ng/mL, respectively. Moreover, the corresponding 90% CIs were 0.09 (0.08-0.10), 0.18 (0.17-0.19), and 0.14 (0.13-0.15), respectively. Nonetheless, in period II, plasma concentrations of total active components (AST2818 and AST5902) changed marginally. The AUC_0-∞ of total active components increased 60%, and the corresponding C_max increased 8%. Possible treatment-related AEs assessed by investigators were fewer in period II (23.3% vs 36.7%). In conclusion, the total exposure of AST2818 and active metabolite AST5902 increased following the coadministration of itraconazole, but it was still safe and well-tolerated.

Inhaled Antifungal Agents for the Treatment and Prophylaxis of Pulmonary Mycoses

Pulmonary mycoses are associated with high morbidity and mortality. The current standard treatment by systemic administration is limited by inadequate local bioavailability and systemic toxic effects. Aerosolisation of antifungals is an attractive approach to overcome these problems, but no inhaled antifungal formulation is currently available for the treatment of pulmonary mycoses. Hence, the development of respirable antifungals formulations is of interest and in high demand. In this review, the recent advances in the development of antifungal formulations for pulmonary delivery are discussed, including both nebulised and dry powder formulations. Although the clinical practices of nebulised parenteral amphotericin B and voriconazole formulations (off-label use) are reported to show promising therapeutic effects with few adverse effects, there is no consensus about the dosage regimen (e.g. the dose, frequency, and whether they are used as single or combination therapy). To maximise the benefits of nebulised antifungal therapy, it is important to establish standardised protocol that clearly defines the dose and specifies the device and the administration conditions. Dry powder formulations of antifungal agents such as itraconazole and voriconazole with favourable physicochemical and aerosol properties are developed using various powder engineering technologies, but it is important to consider their suitability for use in patients with compromised lung functions. In addition, more biological studies on the therapeutic efficacy and pharmacokinetic profile are needed to demonstrate their clinical potential.

Effects of Flutriafol Fungicide on the Lipid Accumulation in Human Liver Cells and Rat Liver

Flutriafol (FTF) is a triazole fungicide that can cause liver toxicity through the ingestion of its residues in food and water. However, little is known about the liver toxicity of FTF, particularly nonalcoholic fatty liver disease (NAFLD) in humans. Therefore, the purpose of this study was to investigate whether FTF induces NAFLD in human liver cells and animal liver. HepG2 cells and Sprague Dawley (SD) rats were treated with FTF at doses of 0–640 µM for 24 h and 0–150 mg/kg bw/day for 28 days, respectively. FTF (80, 160, and 320 µM) treatment to cells induced lipid accumulation. FTF (80 and 160 µM)-treated cells had higher levels of cytochrome P450 enzymes and reactive oxygen species and increased mitochondrial membrane potential loss than the control. FTF also increased the mRNA levels of antioxidant enzymes through oxidative stress and nuclear factor erythroid 2-related factor 2 pathways in HepG2 cells. However, a higher level of FTF (320 µM) induced apoptosis. The treatment of SD rats with FTF (2.5–150 mg/kg bw/day) induced fatty infiltration in the liver by impairing liver metabolism and inducing apoptosis. Therefore, our data suggest that human exposure to FTF residues may be a risk factor for liver diseases, such as NAFLD.

Benzotriazole-5-carboxylic as a mixed-mode ligand for chromatographic separation of antibody with enhanced adsorption capacity

Mixed-mode chromatography provides a promising strategy for industrial protein purification for its potential merit of balancing efficiency and cost-effectiveness. However, mixed-mode media with satisfactory selectivity and binding capacity towards antibody are still urgently needed. A new type of mixed-mode chromatography resin was prepared using benzotriazole-5-carboxylicas as ligand (BTA MM), and its application in antibody separation was explored. A typical pH-dependent protein binding was observed, and the neutral condition was favorable for antibody adsorption. Dynamic binding capacity of human immunoglobulin G (hIgG) was 57.7 mg/mL at pH 7.4 (10 mM phosphate buffer, containing 150 mM NaCl), while elution with acidic solutions (pH 3-4) could achieve a recovery of more than 85%. Protein adsorption on the resin showed a salt-independent manner, thus it could work under physiological solution conditions, with satisfied antibody selectivity. One-step purification of antibody components from human serum samples could obtain a product with the purity more than 84%. Satisfied performance was also observed when the adsorbent was used for purifying a IgG1-type monoclonal antibody (mAb) from cell culture supernatant. In addition, the benzotriazole adsorbent has been found stable enough to withstand autoclave sterilization and other harsh conditions, including 1 M NaOH, 1 M HCl, and 75% ethanol. The results proved the potential of this type of mixed-mode chromatography medium for industrial antibody purification.

Serum 4β-hydroxycholesterol increases during fluconazole treatment

PURPOSE

The antifungal drugs ketoconazole and itraconazole reduce serum concentrations of 4β-hydroxycholesterol, which is a validated marker for hepatic cytochrome P450 (CYP) 3A4 activity. We tested the effect of another antifungal triazole agent, fluconazole, on serum concentrations of different sterols and oxysterols within the cholesterol metabolism to see if this inhibitory reaction is a general side effect of azole antifungal agents.

METHODS

In a prospective, double-blind, placebo-controlled, two-way crossover design, we studied 17 healthy subjects (nine men, eight women) who received 400 mg fluconazole or placebo daily for 8 days. On day 1 before treatment and on day 8 after the last dose, fasting blood samples were collected. Serum cholesterol precursors and oxysterols were measured by gas chromatography-mass spectrometry-selected ion monitoring and expressed as the ratio to cholesterol (R_sterol).

RESULTS

Under fluconazole treatment, serum R_lanosterol and R_24,25-dihydrolanosterol increased significantly without affecting serum cholesterol or metabolic downstream markers of hepatic cholesterol synthesis. Serum R_4β-, R_24S-, and R_27-hydroxycholesterol increased significantly.

CONCLUSION

Fluconazole inhibits the 14α-demethylation of lanosterol and 24,25-dihydrolanosterol, regulated by CYP51A1, without reduction of total cholesterol synthesis. The increased serum level of R_4β-hydroxycholesterol under fluconazole treatment is in contrast to the reductions observed under ketoconazole and itraconazole treatments. The question, whether this increase is caused by induction of CYP3A4 or by inhibition of the catabolism of 4β-hydroxycholesterol, must be answered by mechanistic in vitro and in vivo studies comparing effects of various azole antifungal agents on hepatic CYP3A4 activity.

PRIMARY ADRENAL INSUFFICIENCY SECONDARY TO CHRONIC POSACONAZOLE USE

Objective

Posaconazole (PSO) is commonly used in the treatment of invasive fungal infections. PSO-induced primary adrenal insufficiency (PAI) is rare, and we present what we think to be the third case report of its incidence. We want to bring awareness to this rare but significant side effect that can impact management and monitoring of patients on this medication.

Methods

After clinical assessment, the patient was evaluated with diagnostic studies including measurements of cortisol, adrenocorticotropic hormone, renin activity, and aldosterone levels. Imaging studies such as abdominal computed tomography were also performed.

Results

A 65-year-old man with a history of hemophagocytic lymphohistiocytosis on a dexamethasone taper, complicated with mucormycosis on PSO presented to the emergency department with weakness, fatigue, decreased appetite, orthostatic hypotension, low morning cortisol (0.4 μg/dL), low adrenocorticotropic hormone (3.4 pg/mL), elevated plasma renin (16.7 ng/mL/hour), and low-normal aldosterone (1.7 ng/dL). Abdominal computed tomography imaging revealed bilaterally intact adrenal glands. A diagnosis of PSO-induced PAI was made. Fludrocortisone was initiated in addition to glucocorticoids with improvement of fatigue, appetite, blood pressure, and normalization of sodium and potassium. A month after discontinuing PSO, steroids and fludrocortisone were discontinued with measured morning cortisol of 13 μg/dL and an adrenocorticotropic hormone level of 53.9 pg/mL, both normal.

Conclusion

Available data suggest that the adverse effect profile of PSO is more favorable than other triazoles. However, our case is the third report suggesting that PAI may be an underrecognized side effect. Awareness of this complication is particularly important in patients with severe or resistant fungal infections.

Prediction of ADME-Tox properties and toxicological endpoints of triazole fungicides used for cereals protection

Within this study we have considered 9 triazole fungicides that are approved to be used in European Union for protecting cereals: cyproconazole, epoxiconazole, flutriafol, metconazole, paclobutrazole, tebuconazole, tetraconazole, triadimenol and triticonazole. We have summarized the few available data that support their effects on humans and used various computational tools to obtain a widely view concerning their possible harmful effects on humans. The results of our predictive study reflect that all triazole fungicides considered in this study reveal good oral bioavailability, are envisaged as being able to penetrate the blood brain barrier and to interact with P-glycoprotein and with hepatic cytochromes. The predictions concerning the toxicological endpoints for the investigated triazole fungicides reveal that they. reflect potential of skin sensitization, of blockage of the hERG K+ channels and of endocrine disruption, that they have not mutagenic potential and their carcinogenic potential is not clear. Epoxiconazole and triadimenol are predicted to have the highest potentials of producing numerous harmful effects on humans and their use should be avoided or limited.

Invasive aspergillosis in patients with underlying liver cirrhosis: a prospective cohort study

The aim of this study was to determine the prevalence of invasive aspergillosis (IA) in patients with liver cirrhosis and the performance of serum galactomannan (GM) screening. Patients with decompensated liver cirrhosis and patients with compensated liver cirrhosis presenting with fever and/or respiratory symptoms were prospectively enrolled. All patients were screened by serum GM twice weekly irrespective of clinical signs and symptoms. Positive serum GM triggered work-up consisting of chest computed tomography and in case of pathological findings bronchoscopy. 150 patients were included in the study. Two (1.3%) had probable, one (0.7%) had possible, and 147 (98%) had no evidence of IA. Both patients with probable IA had compensated liver cirrhosis. Sensitivity for serum GM screening for probable versus no IA was 0.5 (95% CI, 0.09-0.91), specificity 0.97 (95% CI: 0.92-0.99), negative predictive value 0.99 (95% CI, 0.96-0.99) and positive predictive value (PPV) 0.17 (95% CI, 0.01-0.64). PPV was 0.5 (95% CI, 0.03-0.98) in patients with clinical suspicion of IA. In conclusion, prevalence of IA in patients with liver cirrhosis seems to be low. Targeted GM testing in case of clinical suspicion of IA may be associated with markedly higher PPVs when compared to universal GM screening in patients with liver cirrhosis.

Improving survival of acute-on-chronic liver failure patients complicated with invasive pulmonary aspergillosis

The mortality of acute-on-chronic liver failure (ACLF) patients complicated with invasive pulmonary aspergillosis (IPA) was extremely high. We aimed to explore prognostic value of the Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) lung score and to establish an optimal voriconazole regimen for ACLF patients complicated with IPA. We retrospectively screened hospitalized ACLF patients in our hospital from July 2011 to April 2016, from which 20 probable IPA cases were diagnosed. Along with onsets of IPA, deteriorated diseases severity, especially lung conditions were found in those 20 ACLF patients. It was found that IPA patients with CLIF-SOFA lung score <2 had better 28-day survival than those with lung score >1 (11/13 vs 0/7, p < 0.001). Based on plasma voriconazole concentration measurement, an optimal voriconazole regimen (loading doses: 0.2 g twice daily; maintenance doses, 0.1 g once daily) was established, which resulted in rational trough plasma drug concentrations (1–5 μg/mL), good clinical outcomes (90-day survival rate of 6/8) and no observed adverse events. In conclusion, CLIF-SOFA lung score >1 was able to identify ACLF patients complicated with IPA encountering much higher 28-day mortality. An optimal voriconazole regimen was safe and effective in our ACLF patients complicated with IPA.

Practice Guidelines for the Diagnosis and Management of Aspergillosis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Isavuconazole in the treatment of invasive aspergillosis and mucormycosis infections

We have a limited arsenal with which to treat invasive fungal infections caused by Aspergillus and Mucorales. The morbidity and mortality for both pathogens remains high. A triazole antifungal, isavuconazole, was recently granted approval by the US Food and Drug Administration and the European Medicines Agency for the treatment of invasive aspergillosis and mucormycosis. A randomized double-blind comparison trial for the treatment of invasive aspergillosis found isavuconazole noninferior to voriconazole. A separate, open-label study evaluating the efficacy of isavuconazole in the treatment of mucormycosis found comparable response rates to amphotericin B and posaconazole treated historical controls. The prodrug isavuconazonium sulfate is commercially available in both an oral and intravenous formulation and is generally well tolerated. Isavuconazole’s broad spectrum of activity, limited side effect profile, and favorable pharmacokinetics will likely solidify its place in therapy.

Drug-Drug Interaction Associated with Mold-Active Triazoles among Hospitalized Patients

The majority of hospitalized patients receiving mold-active triazoles are at risk of drug-drug interactions (DDIs). Efforts are needed to increase awareness of DDIs that pose a serious risk of adverse events. Triazoles remain the most commonly utilized antifungals. Recent developments have included the mold-active triazoles (MATs) itraconazole, voriconazole, and posaconazole, which are first-line agents for the treatment of filamentous fungal infections but have the potential for DDIs. This objective of this study was to evaluate the prevalence of triazole DDIs. Hospitalized U.S. adults with MAT use were identified in the Cerner HealthFacts database, which contained data from over 150 hospitals (2005 to 2013). The severities of DDIs with MATs were categorized, using drug labels and the drug information from the Drugdex system (Thompson Micromedex), into four groups (contraindicated, major, moderate, and minor severity). DDIs of minor severity were not counted. A DDI event was considered to have occurred if the following two conditions were met: (i) the patient used at least one drug with a classification of at least a moderate interaction with the MAT during the hospitalization and (ii) there was a period of overlap between the administration of the MAT and that of the interacting drug of at least 1 day. A total of 6,962 hospitalizations with MAT use were identified. Among them, 88% of hospitalizations with voriconazole use, 86% of hospitalizations with itraconazole use, and 93% of hospitalizations with posaconazole use included the use of a concomitant interacting drug. A total of 68% of hospitalizations with posaconazole use, 34% of hospitalizations with itraconazole use, and 20% of hospitalizations with voriconazole use included the use of at least one drug with a DDI of contraindicated severity. A total of 83% of hospitalizations with posaconazole use, 61% of hospitalizations with itraconazole use, and 82% of hospitalizations with voriconazole use included the use of at least one drug that resulted in a severe DDI. The findings of this study demonstrate that a majority of hospitalized patients receiving MAT are at risk for severe drug-drug interactions and highlight the need for antifungal stewardship.

Role of therapeutic drug monitoring in pulmonary infections: use and potential for expanded use of dried blood spot samples

Respiratory tract infections are among the most common infections in men. We reviewed literature to document their pharmacological treatments, and the extent to which therapeutic drug monitoring (TDM) is needed during treatment. We subsequently examined potential use of dried blood spots as sample procedure for TDM. TDM was found to be an important component of clinical care for many (but not all) pulmonary infections. For gentamicin, linezolid, voriconazole and posaconazole dried blood spot methods and their use in TDM were already evident in literature. For glycopeptides, β-lactam antibiotics and fluoroquinolones it was determined that development of a dried blood spot (DBS) method could be useful. This review identifies specific antibiotics for which development of DBS methods could support the optimization of treatment of pulmonary infections.

Are 1,4- and 1,5-disubstituted 1,2,3-triazoles good pharmacophoric groups?

Over the last decade, 1,2,3-triazoles have received increasing attention in medicinal chemistry thanks to the discovery of the highly useful and widely applicable 1,3-dipolar cycloaddition reaction between azides and alkynes (click chemistry) catalyzed by copper salts and ruthenium complexes. After a decade of medicinal chemistry research on 1,2,3-triazoles, we feel that the time is ripe to demonstrate the real ability of this heterocycle to participate in important and pivotal binding interactions with biological targets while maintaining a good pharmacokinetic profile. In this study, we retrieved and analyzed X-ray crystal structures of complexes between 1,2,3-triazoles and either proteins or DNA to understand the pharmacophoric role of the triazole. Furthermore, the metabolic stability, the capacity to inhibit cytochromes, and the contribution of 1,2,3-triazoles to the overall aqueous solubility of compounds containing them have been analyzed. This information should furnish fresh insight for medicinal chemists in the design of novel bioactive molecules that contain the triazole nucleus.

Evaluation of the effect of food and ketoconazole on the pharmacokinetics of the smoothened inhibitor PF-04449913 in healthy volunteers

PURPOSE

To evaluate the effect of a potent cytochrome P450 3A4 (CYP3A4) inhibitor, ketoconazole, and separately the effect of food on PF-04449913 pharmacokinetics in healthy volunteers.

METHODS

This was an open-label, two-sequence, three-period, three-treatment, single-dose, crossover study. Subjects were randomized to receive single doses of 200 mg PF-04449913 after an overnight fast or after consuming a high-fat meal during Period 1 or 2, with a washout period of at least 8 days. In Period 3, all subjects received ketoconazole (400 mg/day) (days 1-7) and a co-administered single 200-mg PF-04449913 dose (day 4).

RESULTS

Geometric mean ratio of PF-04449913 in the presence of ketoconazole versus PF-04449913 alone was 2.40 [90% confidence interval (CI) 2.15, 2.68] for area under the plasma concentration-time curve from time zero to infinity (AUC(0-inf)) and 1.40 (90% CI 1.24, 1.58) for peak plasma concentration (C max). The geometric mean ratio for fed state compared with fasted state for AUC(0-inf) was 0.87 (90% CI 0.78, 0.97) and for C max was 0.66 (90% CI 0.56, 0.78). PF-04449913 was well tolerated, and all adverse events were mild to moderate.

CONCLUSIONS

PF-04449913 plasma exposures and peak concentrations were increased following concurrent administration of ketoconazole in healthy volunteers. These findings provide the upper limit for expected PF-04449913 exposures after co-administration of a strong CYP3A4 inhibitor in patients with cancer who routinely receive antifungal azoles. While a high-fat meal decreased PF-04449913 exposure, the differences in plasma exposure under the two conditions were not considered clinically meaningful.

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.

Rational development of 4-aminopyridyl-based inhibitors targeting Trypanosoma cruzi CYP51 as anti-chagas agents

A new series of 4-aminopyridyl-based lead inhibitors targeting Trypanosoma cruzi CYP51 (TcCYP51) has been developed using structure-based drug design as well as structure-property relationship (SPR) analyses. The screening hit starting point, LP10 (KD ≤ 42 nM; EC50 = 0.65 μM), has been optimized to give the potential leads 14t, 27i, 27q, 27r, and 27t, which have low-nanomolar binding affinity to TcCYP51 and significant activity against T. cruzi amastigotes cultured in human myoblasts (EC50 = 14-18 nM for 27i and 27r). Many of the optimized compounds have improved microsome stability, and most are selective against human CYPs 1A2, 2D6, and 3A4 (<50% inhibition at 1 μM). A rationale for the improvement in microsome stability and selectivity of inhibitors against human metabolic CYP enzymes is presented. In addition, the binding mode of 14t with the Trypanosoma brucei CYP51 (TbCYP51) orthologue has been characterized by X-ray structure analysis.

Complexes of Trypanosoma cruzi sterol 14α-demethylase (CYP51) with two pyridine-based drug candidates for Chagas disease: structural basis for pathogen selectivity

Chagas disease, caused by the eukaryotic (protozoan) parasite Trypanosoma cruzi, is an alarming emerging global health problem with no clinical drugs available to treat the chronic stage. Azole inhibitors of sterol 14α-demethylase (CYP51) were proven effective against Chagas, and antifungal drugs posaconazole and ravuconazole have entered clinical trials in Spain, Bolivia, and Argentina. Here we present the x-ray structures of T. cruzi CYP51 in complexes with two alternative drug candidates, pyridine derivatives (S)-(4-chlorophenyl)-1-(4-(4-(trifluoromethyl)phenyl)-piperazin-1-yl)-2-(pyridin-3-yl)ethanone (UDO; Protein Data Bank code 3ZG2) and N-[4-(trifluoromethyl)phenyl]-N-[1-[5-(trifluoromethyl)-2-pyridyl]-4-piperi-dyl]pyridin-3-amine (UDD; Protein Data Bank code 3ZG3). These compounds have been developed by the Drugs for Neglected Diseases initiative (DNDi) and are highly promising antichagasic agents in both cellular and in vivo experiments. The binding parameters and inhibitory effects on sterol 14α-demethylase activity in reconstituted enzyme reactions confirmed UDO and UDD as potent and selective T. cruzi CYP51 inhibitors. Comparative analysis of the pyridine- and azole-bound CYP51 structures uncovered the features that make UDO and UDD T. cruzi CYP51-specific. The structures suggest that although a precise fit between the shape of the inhibitor molecules and T. cruzi CYP51 active site topology underlies their high inhibitory potency, a longer coordination bond between the catalytic heme iron and the pyridine nitrogen implies a weaker influence of pyridines on the iron reduction potential, which may be the basis for the observed selectivity of these compounds toward the target enzyme versus other cytochrome P450s, including human drug-metabolizing P450s. These findings may pave the way for the development of novel CYP51-targeted drugs with optimized metabolic properties that are very much needed for the treatment of human infections caused by eukaryotic microbial pathogens.

Steady-state pharmacokinetics of oral voriconazole and its primary metabolite, N-oxide voriconazole, pre- and post-autologous peripheral stem cell transplantation

Voriconazole (VCZ) is frequently utilized for prevention and treatment of invasive fungal infections in peripheral stem cell transplant (PSCT) patients. We performed an open-label pharmacokinetic study to compare VCZ and N-oxide voriconazole (N-oxide VCZ) pharmacokinetics in patients pre- and post-PSCT. Ten patients completed both sampling periods. The pharmacokinetics of VCZ were unchanged; however, those of N-oxide VCZ were significantly different pre- and post-PSCT.

Optimizing antifungal choice and administration

BACKGROUND

The antifungal armamentarium includes a number of drug classes and agents within each class. Successful IFI management depends on optimal matching of drug choice with the individual patient and causative pathogen, and maximizing effectiveness of the selected drug through appropriate dosing and toxicity management.

OBJECTIVE

This review is intended to provide a brief overview of key factors involved in optimizing antifungal choice and administration for patients with invasive fungal infections (IFIs).

FINDINGS

Antifungals differ in spectrum of activity, and these differences are critical when selecting the antifungal most likely to provide success for a patient with an IFI. When the species has not yet been identified, an analysis of regional epidemiology and risk factors can provide clues as to the most likely pathogen. For severely immunocompromised patients, a fungicidal agent may be preferred over a fungistatic agent, although more research is needed in this area. Triazoles, particularly itraconazole and posaconazole, exhibit great interpatient pharmacokinetic variability related to absorption. Steps can be taken to maximize absorption when using these agents. Voriconazole concentration is affected by polymorphisms in the major metabolic enzyme, cytochrome P450 2C19. Triazoles, and to a lesser extent other antifungals, are also subject to drug-drug interactions, which needs to be considered when selecting a particular antifungal agent for use in a severely ill patient on polypharmacy. Therapeutic drug monitoring may be a useful adjunct for patients receiving itraconazole, voriconazole, or posaconazole. When the IFI involves a pharmacologically protected site, such as the central nervous system (CNS) or eye, 5-fluorocytosine, fluconazole, or voriconazole are generally preferred. Echinocandin penetration is typically inadequate for IFIs of the CNS or eye. Antifungal agents also differ in their toxicity profiles, and these issues also need to be considered and managed when making an antifungal choice.

CONCLUSION

Successful management of IFIs relies in part on the accurate selection of an antifungal agent for the infection. Drug characteristics can help in the selection of drug therapy. These characteristics include the drug's spectrum of activity, pharmacokinetics, pharmacodynamics, toxicity profile, and distribution to the infection site. Matching the drug profile to the patient and fungal species contribute to optimal management of infection.