Efficacy and safety of voriconazole in the treatment of acute invasive aspergillosis

Fungal infection in solid organ recipients

In solid organ recipients, as with other immunosuppressed patients, infections by Candida spp. and Aspergillus spp. are the most frequent invasive mycoses. Infections by Cryptococcus spp. and fungi of the Mucorales order are less common. Infections by Fusarium spp. and Scedosporium spp. are very uncommon, except in patients undergoing hematopoietic stem cell transplant and patients with prolonged neutropenia. The risk factors for fungal infection are immunosuppression, surgery, viral co-infection, and environmental exposure. Diagnosis is challenging: blood culture is of little use, except in candidiasis and cryptococcosis, and the poor accuracy of antigen-based techniques, except in cryptococcosis, favors widespread use of empirical therapy. A delay in the initiation of therapy increases the already high mortality of these infections. The agents used to treat fungal infection are azoles, echinocandins, and lipid amphotericin. Administration depends on antifungal activity, drug-drug interactions with calcineurin inhibitors, and safety profiles (effects on grafts and other side effects).

Role of therapeutic drug monitoring of voriconazole in the treatment of invasive fungal infections

BACKGROUND

Voriconazole is a broad-spectrum, second-generation triazole antifungal agent with demonstrated efficacy in the treatment of invasive fungal infections caused by Aspergillus spp. and Candida spp. Given the characteristically poor prognosis of patients with invasive fungal infections and the protracted duration of treatment required, therapeutic monitoring of voriconazole is, in theory, an attractive method to optimize antifungal therapy.

OBJECTIVE

To determine the utility of therapeutic drug monitoring for voriconazole.

METHODS

A previously published decision-making algorithm was used to assess the currently available literature on therapeutic drug monitoring of voriconazole.

RESULTS

Several analytical methods can be used to quantify plasma or serum concentrations of voriconazole. Reasons for therapeutic monitoring of this drug include wide variability both within and between individuals secondary to drug properties, drug-drug interactions, and disease states. Furthermore, voriconazole follows nonlinear pharmacokinetics with saturable hepatic clearance. Another potential factor in favour of therapeutic drug monitoring for voriconazole is genetic polymorphism of CYP2C19, whereby patients who are homozygous for poor metabolism (about 19% of non-Indian Asians) can have 4-fold greater exposure to voriconazole. The concentrations of this drug are also greater in patients with hepatic impairment. Drug-drug interactions with other substrates of CYP2C9, CYP2C19, and CYP3A4 can also alter voriconazole concentrations. However, the correlations between plasma concentrations of voriconazole and its efficacy and toxicity are not well defined. Although lower and upper target thresholds of 0.25-2 mg/L and 4-6 mg/L, respectively, have been suggested, studies to date have not been appropriately designed or powered to reveal any definitive association.

CONCLUSIONS

Routine therapeutic drug monitoring of voriconazole is not recommended except in certain circumstances, such as lack of response to therapy or evidence of toxicity, in which case selective monitoring of voriconazole concentrations may be of clinical utility.

Monitoring of voriconazole plasma concentrations in immunocompromised paediatric patients

OBJECTIVES

Voriconazole is approved for management of invasive fungal diseases (IFDs) in paediatric patients. We analysed plasma trough concentrations and explored their association with endpoints of antifungal therapy.

PATIENTS AND METHODS

The cohort included 74 immunocompromised patients (0.2-18 years of age) who received 101 courses of voriconazole for possible (7) and probable/proven (13) IFDs, as prophylaxis (79) or empirical therapy (2). Voriconazole was given intravenously (4), intravenously and orally (15) and orally (82) at recommended dosages until intolerance or maximum efficacy. IFDs and outcomes were assessed by EORTC/MSG consensus criteria.

RESULTS

Voriconazole was administered at a median maintenance dosage of 4.8 mg/kg twice daily (range 2.2-17.4) for a median of 40 days (range 6-1002). Trough plasma concentrations at steady state (251 samples; 3.4 ± 4.3/patient) ranged from <0.2 to 14.9 mg/L with high intra- and inter-individual variability and no apparent relationship to dose (P = 0.074, ANOVA). Of the samples 22%, 42% and 58% had voriconazole concentrations <0.2, ≤0.5 and ≤1.0 mg/L, respectively. Adverse events (AEs) occurred in 77/101 (76.2%) courses and were mostly grade I or II. Ten courses (9.9%) were discontinued due to AEs. Treatment success was observed in 8/20 patients (40%) with IFDs, and in 67/81 courses (82.7%) of empirical therapy/prophylaxis. There were no consistent correlations between dose, trough concentrations and laboratory/clinical AEs or treatment response, and proposed threshold values were not discriminative.

CONCLUSIONS

Voriconazole had acceptable safety and useful efficacy in the management of paediatric IFDs. Pharmacokinetic variability was high and no predictable dose-concentration-effect relationships were observed.

Voriconazole for chronic pulmonary aspergillosis: a prospective multicenter trial

Early evidence suggests the efficacy of voriconazole for chronic pulmonary aspergillosis (CPA). We conducted a prospective, open, multicenter trial to evaluate the efficacy and safety of voriconazole for proven CPA in minimally or non-immunocompromised patients. Patients had CPA confirmed by chest computed tomography (CT) and/or endoscopy, positive Aspergillus culture from a respiratory sample, and positive serologic test for Aspergillus precipitins. Patients received voriconazole (200 mg twice daily) for a period of 6-12 months and were followed for 6 months after the end of therapy (EOT). The primary endpoint was global success at 6 months, defined as complete or partial (≥50 % improvement) radiological response and mycological eradication. Forty-one patients with confirmed CPA were enrolled. All patients had A. fumigatus as the etiologic agent. By EOT, five patients had died from comorbidities and seven had discontinued voriconazole due to toxicity. The global success rate at 6 months was 13/41 (32 %): 10/19 (53 %) for chronic necrotizing aspergillosis and 3/22 (14 %) for chronic cavitary aspergillosis (p = 0.01). The respective success rates at EOT were 58 and 32 %. Clinical symptoms and quality of life also improved during treatment. Voriconazole is effective for CPA, with acceptable toxicity. The response rate is higher and obtained more rapidly in necrotizing than cavitary forms.

The effect of therapeutic drug monitoring on safety and efficacy of voriconazole in invasive fungal infections: a randomized controlled trial

BACKGROUND

Blood levels of voriconazole, a first line therapy for invasive aspergillosis, may correlate with adverse events and treatment response. However, no randomized controlled studies have been conducted to evaluate the clinical utility of routine therapeutic drug monitoring (TDM) of voriconazole. This study aimed to determine whether routine TDM of voriconazole reduces drug adverse events or improves treatment response in invasive fungal infections.

METHODS

This was a randomized, assessor-blinded, controlled, single center trial. One hundred ten adult patients were randomly assigned to TDM or non-TDM groups. In the TDM group, voriconazole dosage was adjusted (target range, 1.0-5.5 mg/L) according to the serum trough level measured on the fourth day after initiation of voriconazole. The non-TDM group received a fixed, standard dosage. Voriconazole-related adverse events were monitored, and treatment response was assessed three months after the initiation of therapy.

RESULTS

Baseline characteristics including the CYP2C19 genotype were comparable between the two groups. While the incidence of adverse events was not different between the TDM group and the non-TDM group (both 42%; P = .97), the proportion of voriconazole discontinuation due to adverse events was significantly lower in the TDM group than in the non-TDM group (4% vs 17%; P = .02). A complete or partial response was observed in 81% (30 of 37) of patients in the TDM group compared to 57% (20 of 34) in the non-TDM group (P = .04).

CONCLUSIONS

Routine TDM of voriconazole may reduce drug discontinuation due to adverse events and improve the treatment response in invasive fungal infections.

CLINICAL TRIAL REGISTRATION

NCT00890708.

Risk factors for voriconazole hepatotoxicity at 12 weeks in lung transplant recipients

Voriconazole is commonly used for prophylaxis and treatment of invasive aspergillosis in lung transplant recipients. However, the use of voriconazole may at times be limited by the development of hepatotoxicity. Our goal is to determine predictors of voriconazole-associated hepatotoxicity in lung transplant recipients. We conducted a single center retrospective cohort study of lung transplant recipients from 2006 to 2010 who received voriconazole therapy. We compared characteristics of patients who developed hepatotoxicity and those who did not. One hundred five lung transplant recipients received voriconazole. Hepatotoxicity occurred in 51% (54/105) of patients and lead to discontinuation in 34% (36/105). In univariate analysis, age less than 40 years, cystic fibrosis, use of azathioprine, history of liver disease and early initiation of voriconazole were associated with hepatotoxicity. In multivariable logistic regression analysis, perioperative initiation of voriconazole (within 30 days of transplantation) was independently associated with hepatotoxicity (OR 4.37, 95% CI: 1.53-12.43, p = 0.006). The five risk factors identified in the univariate analysis were used to build a K-nearest neighbor algorithm predictive model for hepatotoxicity. This model predicted hepatotoxicity with an accuracy of 70%. Voriconazole therapy initiated within the first 30 days of transplantation is associated with a greater risk of developing hepatotoxicity.

Initial voriconazole trough blood levels and clinical outcomes of invasive aspergillosis in patients with hematologic malignancies

There are limited data on the relationship between voriconazole levels and clinical outcomes relative to invasive aspergillosis (IA). We therefore analyzed the association between initial voriconazole trough blood levels and clinical responses of IA in patients with hematologic malignancies. All adult patients treated with voriconazole in a tertiary care hospital in Seoul, South Korea, between August 2009 and April 2011 were identified from pharmacy records. Initial voriconazole trough levels were routinely measured 1 week after therapy and patient responses were classified as success (complete or partial response) or failure (stable response, progression of disease, or death) at 2 weeks post-therapy. Fifty-two patients, involving 2 (4%) proven, 29 (56%) probable, and 21 (40%) possible IA infections, were included. Of these, 11 (21%) had initial voriconazole levels of ≤ 2 mg/l and the remaining 41 (79%) had > 2 mg/l. There were slightly fewer successful responses (45%, 5/11) in the patients with initial voriconazole levels ≤ 2 mg/l than in those with voriconazole levels > 2 mg/l (51%, 21/41), but the difference was not statistically significant (P= 0.73). Neutropenia (OR 0.1, P= 0.008) and immunosuppression (OR 0.1, P= 0.004) were independently associated with 2-week successful response after voriconazole therapy. In conclusion, initial voriconazole trough levels may not significantly affect clinical outcomes of IA at 2 weeks after voriconazole therapy in patients with hematologic malignancies. Further studies of prospective design are needed to establish the optimal procedure for voriconazole drug monitoring.

Therapeutic drug monitoring of voriconazole in children

Voriconazole is an extended-spectrum triazole antifungal with activity against a wide variety of pathogens, including Aspergillus, Candida, Cryptococcus neoformans, Fusarium, and Scedosporium. It exerts its antifungal activity by blocking the synthesis of fungal cell membranes and is considered the first-line treatment for invasive aspergillosis. Because the pharmacokinetics of voriconazole can demonstrate considerable variability, it has been suggested that monitoring plasma levels of voriconazole may play an important role in optimizing the efficacy and safety of the drug in complex patients like those at risk of or who have invasive aspergillosis. In this article, we review the criteria for therapeutic drug monitoring and assess the evidence for using plasma voriconazole concentrations to individualize doses in children.

Concurrent lung infections in patients with hematological malignancies and invasive pulmonary aspergillosis: how firm is the Aspergillus diagnosis?

BACKGROUND

Immunocompromised patients with hematological malignancies and/or recipients of hematopoietic stem cell transplants are constantly exposed to several fungal, bacterial, and viral respiratory pathogens.

METHODS

We retrospectively evaluated all patients with invasive pulmonary aspergillosis (IPA) and underlying hematological malignancies for the presence of concurrent, microbiologically documented pulmonary infections during a 5-year period (2005-2010).

RESULTS

We found 126 such patients that frequently had coinfections (49%) with respiratory pathogens other than Aspergillus species, with a higher rate in patients with probable IPA (53%) than in those with proven IPA (29%; P=0.038).

CONCLUSIONS

As the majority of patients with IPA in daily practice have probable IPA, often according to only the combination of positivity for serological biomarkers and radiological findings, our data may raise skepticism about both the certainty of IPA diagnosis and the evaluation of response to antifungals in a subset of these patients.

Prospective, observational study of voriconazole therapeutic drug monitoring among lung transplant recipients receiving prophylaxis: factors impacting levels of and associations between serum troughs, efficacy, and toxicity

Voriconazole prophylaxis is common following lung transplantation, but the value of therapeutic drug monitoring is unknown. A prospective, observational study of lung transplant recipients (n = 93) receiving voriconazole prophylaxis was performed. Serum voriconazole troughs (n = 331) were measured by high-pressure liquid chromatography. The median initial and subsequent troughs were 1.91 and 1.46 μg/ml, respectively. The age of the patient directly correlated with initial troughs (P = 0.005). Patients that were ≥ 60 years old and cystic fibrosis patients were significantly more likely to have higher and lower initial troughs, respectively. In 95% (88/93) of patients, ≥ 2 troughs were measured. In 28% (25/88) and 32% (28/88) of these patients, all troughs were ≤ 1.5 μg/ml or >1.5 μg/ml, respectively. Ten percent (10/93) and 27% (25/93) of the patients developed invasive fungal infection (tracheobronchitis) and fungal colonization, respectively. The median troughs at the times of positive and negative fungal cultures were 0.92 and 1.72 μg/ml (P = 0.07). Invasive fungal infections or colonization were more likely with troughs of ≤ 1.5 μg/ml (P = 0.01) and among patients with no trough of >1.5 μg/ml (P = 0.007). Other cutoff troughs correlated less strongly with microbiologic outcomes. Troughs correlated directly with aspartate transferase levels (P = 0.003), but not with other liver enzymes. Voriconazole was discontinued due to suspected toxicity in 27% (25/93) of the patients. The troughs did not differ at the times of suspected drug-induced hepatotoxicity, central nervous system (CNS) toxicity, or nausea/vomiting and in the absence of toxicity. Voriconazole prophylaxis was most effective at troughs of >1.5 μg/ml. A cutoff for toxicity was not identified, but troughs of >4 μg/ml were rare. The data support a target range of >1.5 to 4 μg/ml.

Outcome of Antifungal Combination Therapy for Invasive Mold Infections in Hematological Patients is Independent of the Chosen Combination

Invasive mold infection (IMI) remains a major cause of mortality in high-risk hematological patients. The aim of this multicenter retrospective, observational study was to evaluate antifungal combination therapy (ACT) for proven and probable IMI in hematological patients. We analyzed 61 consecutive cases of proven (n=25) and probable (n=36) IMI treated with ACT collected from eight Spanish hospitals from January 2005 to December 2009. Causal pathogens were: Aspergillus spp (n=49), Zygomycetes (n=6), Fusarium spp (n=3), and Scedosporium spp (n=3). Patients were classified in three groups according to the antifungal combination employed: Group A, liposomal amphotericin B (L-AmB) plus caspofungin (n=20); Group B, LAmB plus a triazole (n=20), and Group C, voriconazole plus a candin (n=21). ACT was well tolerated with minimal adverse effects. Thirty-eight patients (62%) achieved a favorable response (35 complete). End of treatment and 12-week survival rates were 62% and 57% respectively, without statistical differences among groups. Granulocyte recovery was significantly related to favorable response and survival (p<0.001) in multivariate analysis. Our results suggest that comparable outcomes can be achieved with ACT in high risk hematological patients with proven or probable IMI, whatever the combination of antifungal agents used.

[Pulmonary aspergillosis complicating atypical mycobacterial infection in two patients suffering from chronic obstructive pulmonary disease]

INTRODUCTION

Atypical mycobacteria and Aspergillus are opportunistic organisms responsible for severe pulmonary diseases whose development is encouraged by the presence of chronic obstructive pulmonary disease (COPD) and related immunosuppression.

CASE REPORTS

We report the cases of two patients, both alcoholics with emphysematous COPD, who developed chronic pulmonary aspergillosis following atypical mycobacterial infection. Patient 1 developed chronic necrotising aspergillosis several months after the diagnosis of infection with Mycobacterium avium. Patient 2 developed an aspergilloma several weeks after the diagnosis of infection with Mycobacterium xenopi. The association of these two pathologies presents diagnostic and therapeutic problems that are discussed.

CONCLUSION

The development of Aspergillus pulmonary disease may complicate atypical mycobacterial infections and explain a poor response to treatment. Our two case reports suggest that a systematic search should be made for pulmonary aspergillosis during the follow-up of patients with atypical mycobacterial infection.

Investigation and threshold of optimum blood concentration of voriconazole: a descriptive statistical meta-analysis

Voriconazole (VRCZ) reportedly possesses a broad spectrum of antifungal activity against Aspergillus spp. and Candida spp., and the blood concentration of VRCZ is correlated with both the efficacy and the adverse effects of this drug. Monitoring of the blood concentration target level of VRCZ has not yet been widely adopted in the medical field, and no evidence concerning this target level has been reported. Accordingly, we used a meta-analysis to investigate the optimal blood concentration of VRCZ. Using data from 12 reports, we found that the success rate for fungal infection treatment increased significantly at VRCZ levels greater than 1.0 μg/ml when a graded cutoff value within the range of 1.0-3.0 μg/ml was used as the VRCZ trough blood concentration [odds ratio (OR) 7.23, 95% confidence interval (CI) 2.84-18.37, P < 0.0001]. Concerning the safety evaluation, the incidence of adverse neurological effects increased significantly at a cutoff value of 4.0 μg/ml when a graded cutoff value within the range of 3.0-6.0 μg/ml was used (OR 2.23, 95% CI 1.12-4.46, P = 0.02). However, in all 12 literature sources, an increasing incidence of liver dysfunction was reported at higher blood concentrations, and no accurate cutoff values were obtained. Consequently, a VRCZ trough blood concentration more than 1.0 μg/ml from the perspective of efficacy and less than 4.0 μg/ml from the perspective of safety is recommended.

Invasive Fungal Sinusitis

Invasive sinus Aspergillus infection has been reported in the last decade with increased frequency, most commonly in the setting of hematologic malignancy, neutropenia, HIV infection and other states of immunosuppression. Fungal rhinosinusitis can be broadly classified into two varieties-invasive and noninvasive on the basis of tissue invasion. Invasive fungal sinusitis are acute invasive, chronic invasive (both granulomatous and nongranulomatous forms), whereas noninvasive are fungus balls and allergic fungal sinusitis. Invasive fungal sinusitis is one of the most challenging forms of sinonasal pathology to manage, most commonly presenting in immunocompromised individuals. Chronic invasive being sinus aspergillosis (CISA) is being reported in immunocompetent patients at an increasing rate while most of these cases are being reported from the India subcontinent and middle east. Invasive fungal sinusitis is on the rise worldwide and especially in north India as it is endemic in this part of the country. It is affecting immunocompetent young and middle aged population causing a great morbidity and mortality. This entity needs to be picked up early by spreading awareness among the family physicians, internists, otolaryngologists, ophthalmologists, neurosurgeons, pulmonary physicians, critical care specialists so that an early management can initiated to achieve better control over the disease. This review is an attempt to initiate an interdisciplinary approach to achieve a better outcome.

How to cite this article

Gupta AK, Bansal S, Rijuneeta, Gupta B. Invasive Fungal Sinusitis. Clin Rhinol An Int J 2012;5(2): 63-71.

Voriconazole drug monitoring in the management of invasive fungal infection in immunocompromised children: a prospective study

OBJECTIVES

To evaluate voriconazole plasma level monitoring in immunocompromised children and determine the relationship of plasma levels with dose, safety and efficacy.

METHODS

We used a prospective study including all consecutive children with invasive fungal infection (IFI) treated with voriconazole between August 2008 and May 2010. IFI diagnosis and clinical outcome evaluation were based on European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group ('EORTC/MSG') definitions.

RESULTS

A total of 196 voriconazole plasma trough measurements from 30 patients (median age 10 years) obtained during 2135 days of voriconazole therapy were analysed. Nineteen patients (63%) presented with proven or probable IFI. Voriconazole plasma levels varied widely and 73% of patients required dose adjustment. The median voriconazole dose was 20 mg/kg/day and the median duration of therapy was 6 weeks. Age 5 was the smallest value defining two groups on which the correlation between dose and plasma levels had a different behaviour, and this relationship was especially significant for patients <5 years old (Spearman's rank correlation coefficient=0.38213, P=0.008). For patients <5 years old the median dose to achieve therapeutic levels was 38.0 mg/kg/day (12-40.0) and for those ≥5 years old it was 15 mg/kg (4-52). Voriconazole plasma levels showed a significant relationship with early outcome (P=0.0268), but not late outcome (P=0.2015). Overall mortality was 42% and a significant relationship with voriconazole therapeutic plasma levels was not demonstrated. A significant relationship was established between plasma levels above normal range and skin and neurological toxicity (P=0.0001), but this could not be demonstrated for liver toxicity.

CONCLUSIONS

Our study confirms the large variability in voriconazole trough plasma levels in children and a trend to non-linear pharmacokinetics in older patients. In addition, doses significantly higher than those recommended in younger children seem warranted and a significant relationship between plasma voriconazole above the normal range and some adverse events is confirmed.

A novel vesicular carrier, transethosome, for enhanced skin delivery of voriconazole: characterization and in vitro/in vivo evaluation

This study describes a novel carrier, transethosome, for enhanced skin delivery of voriconazole. Transethosomes (TELs) are composed of phospholipid, ethanol, water and edge activator (surfactants) or permeation enhancer (oleic acid). Characterization of the TELs was based on results from recovery, particle size, transmission electron microscopy (TEM), zeta potential and elasticity studies. In addition, skin permeation profile was obtained using static vertical diffusion Franz cells and hairless mouse skin treated with TELs containing 0.3% (w/w) voriconazole, and compared with those of ethosomes (ELs), deformable liposomes (DLs), conventional liposomes (CLs) and control (polyethylene glycol, PG) solutions. The recovery of the studied vesicles was above 90% in all vesicles, as all of them contained ethanol (7-30%). There was no significant difference in the particles size of all vesicles. The TEM study revealed that the TELs were in irregular spherical shape, implying higher fluidity due to perturbed lipid bilayer compared to that of other vesicles which were of spherical shape. The zeta potential of vesicles containing sodium taurocholate or oleic acid showed higher negative value compared to other vesicles. The elasticities of ELs and TELs were much higher than that of CLs and DLs. Moreover, TELs dramatically enhanced the skin permeation of voriconazole compared to the control and other vesicles (p<0.05). Moreover, the TELs enhanced both in vitro and in vivo skin deposition of voriconazole in the dermis/epidermis region compared to DLs, CLs and control. Therefore, based on the current study, the novel carrier TELs could serve as an effective dermal delivery for voriconazole.

Voriconazole serum levels measured by high-performance liquid chromatography: a monocentric study in treated patients

In this study we present the results of a therapeutic drug monitoring retrospective analysis involving 14 patients with several underlying diseases who were receiving voriconazole for the treatment of fungal infections. A simple high performance liquid chromatography assay with ultraviolet detection was used in the drug monitoring. We report here that serum concentrations were highly variable and unpredictable in most patients. We also found that lack of response was more frequent in patients with levels persistently lower than 1 mg/l. The number of samples with voriconazole concentrations below 1 mg/l was significantly higher in patients who exhibited therapeutic failures (88% versus 27%; P < 0.001). In addition, the period of time in which voriconazole concentrations were maintained below 1 mg/l was slightly higher in patients in the failure group. We suggest that serum concentration should be individually quantified for patients receiving voriconazole therapy. Further prospective studies are needed to clarify the potential benefit of the individualization of treatment.

Phototoxicity and photocarcinogenesis associated with voriconazole

The antifungal voriconazole was given its marketing authorization in 2002. Several kinds of adverse effects have been reported, including acute and chronic cutaneous adverse effects, mainly due to a phototoxicity mechanism. More recently, some authors have reported that voriconazole was involved in the occurrence of multiple and often-aggressive cutaneous squamous cell carcinomas if the treatment was maintained for a long time. According to safety data in studies assessing voriconazole effectiveness, 8% of outpatients may experience phototoxic events. An overview of the different types of phototoxicity and of the concerned population was given by the 61 published case reports of photo-induced voriconazole-related skin adverse events (including 18 cases of squamous cell carcinomas). The most likely mechanisms may be phototoxicity directly related to either voriconazole or to its N-oxide main metabolite, and an interaction with retinoid metabolism; moreover, immunodeficiency may enhance the risk of skin cancer. Several issues remain to be investigated, and studies are needed concerning the phototoxicity and photocarcinogenesis of voriconazole and the prognosis of chronic non-malignant skin lesions. Voriconazole prescription must be associated with strict photoprotection; in case of a phototoxic adverse event, another azole may be recommended.

An observational efficacy and safety analysis of the treatment of acute invasive aspergillosis using voriconazole

The purpose of this study was to evaluate efficacy and safety of voriconazole in patients with acute invasive aspergillosis (IA) in a real-life, clinical setting. This was a multicenter observational study in adult patients treated with voriconazole for invasive mycosis. The study evaluated clinical response, mortality, use of other licensed antifungal therapy (OLAT), and treatment duration. This sub-analysis evaluated treatment and outcome data specifically from adult patients with proven/probable IA, while safety data were assessed in patients with proven/probable/possible IA. Of the 141 patients enrolled, 113 were adults with proven/probable IA and six had possible IA. Voriconazole treatment duration ranged from 1 to 183 days (median, 49.5 days). Voriconazole was used exclusively in 64% (72/113) of patients and in combination/sequentially with OLAT in 36%. Overall successful treatment response was 50% (57/113 patients). Twelve percent (14/113) of patients were switched to OLAT, either because of insufficient response (four patients) or for safety reasons (10 patients). Overall and attributable (entirely or partially due to fungal infection) mortality rates were 52% (59/113) and 17%, respectively. Treatment-related adverse events were reported for 18% (22/119) of patients. This observational study confirms the results of previous clinical trials demonstrating voriconazole as an effective and safe agent for treatment of confirmed acute IA.

Comparison of pharmacokinetics and safety of voriconazole intravenous-to-oral switch in immunocompromised children and healthy adults

Voriconazole pharmacokinetics are not well characterized in children despite prior studies. To assess the appropriate pediatric dosing, a study was conducted in 40 immunocompromised children aged 2 to <12 years to evaluate the pharmacokinetics and safety of voriconazole following intravenous (IV)-to-oral (PO) switch regimens based on a previous population pharmacokinetic modeling: 7 mg/kg IV every 12 h (q12h) and 200 mg PO q12h. Area under the curve over the 12-h dosing interval (AUC(0-12)) was calculated using the noncompartmental method and compared to that for adults receiving approved dosing regimens (6 → 4 mg/kg IV q12h, 200 mg PO q12h). On average, the AUC(0-12) in children receiving 7 mg/kg IV q12h on day 1 and at IV steady state were 7.85 and 21.4 μg · h/ml, respectively, and approximately 44% and 40% lower, respectively, than those for adults at 6 → 4 mg/kg IV q12h. Large intersubject variability was observed. At steady state during oral treatment (200 mg q12h), children had higher average exposure than adults, with much larger intersubject variability. The exposure achieved with oral dosing in children tended to decrease as weight and age increased. The most common treatment-related adverse events were transient elevated liver function tests. No clear threshold of voriconazole exposure was identified that would predict the occurrence of treatment-related hepatic events. Overall, voriconazole IV doses higher than 7 mg/kg are needed in children to closely match adult exposures, and a weight-based oral dose may be more appropriate for children than a fixed dose. Safety of voriconazole in children was consistent with the known safety profile of voriconazole.

Comparison of pharmacokinetics and safety of voriconazole intravenous-to-oral switch in immunocompromised adolescents and healthy adults

The current voriconazole dosing recommendation in adolescents is based on limited efficacy and pharmacokinetic data. To confirm the appropriateness of dosing adolescents like adults, a pharmacokinetic study was conducted in 26 immunocompromised adolescents aged 12 to <17 years following intravenous (IV) voriconazole to oral switch regimens: 6 mg/kg IV every 12 h (q12h) on day 1 followed by 4 mg/kg IV q12h, then switched to 300 mg orally q12h. Area under the curve over a 12-hour dosing interval (AUC(0-12)) was calculated using a noncompartmental method and compared to the value for adults receiving the same dosing regimens. On average, the AUC(0-12) in adolescents after the first loading dose on day 1 and at steady state during IV treatment were 9.14 and 22.4 μg·h/ml, respectively (approximately 34% and 36% lower, respectively, than values for adults). At steady state during oral treatment, adolescents also had lower average exposure than adults (16.7 versus 34.0 μg·h/ml). Larger intersubject variability was observed in adolescents than in adults. There was a slight trend for some young adolescents with low body weight to have lower voriconazole exposure. It is likely that these young adolescents may metabolize voriconazole more similarly to children than to adults. Overall, with the same dosing regimens, voriconazole exposures in the majority of adolescents were comparable to those in adults. The young adolescents with low body weight during the transitioning period from childhood to adolescence (e.g., 12 to 14 years old) may need to receive higher doses to match the adult exposures. Safety of voriconazole in adolescents was consistent with the known safety profile of voriconazole.

Voriconazole-related severe adverse events: clinical application of therapeutic drug monitoring in Korean patients

BACKGROUND

Voriconazole is a triazole agent with excellent antifungal activity against Aspergillus species. However, despite its potential advantages, the occurrence of unpredictable toxicities might be critical in immunocompromised patients. The aim of this study was to analyze risk factors for voriconazole-related severe adverse events (SAEs).

METHODS

This prospective observational study was conducted in Korean patients with hematological malignancies and invasive aspergillosis on intravenous voriconazole therapy between June 2008 and April 2009.

RESULTS

Of the 25 patients enrolled, eight (32%) showed voriconazole-related SAEs, which included hepatotoxicities (n=5), cardiac tachyarrhythmias (n=2), and neurotoxicity (n=1). Sex, age, underlying hematological malignancies, voriconazole dose, the co-administration of a proton pump inhibitor, and CYP2C19 genotype were not found to be related to the occurrence of SAEs. However, trough plasma concentrations of voriconazole were found to be significantly higher in the patients with an SAE: median 6.32 mg/l (interquartile range (IQR) 2.86-9.71 mg/l) vs. median 2.15 mg/l (IQR 0.92-4.00 mg/l); p=0.011. Receiver operating characteristic curve analysis identified a cut-off trough concentration for SAEs of 5.83 mg/l (sensitivity 62.5% and specificity 94.1%). Furthermore, multivariate analysis showed that a trough concentration of ≥ 5.83mg/l was the only significant independent risk factor of an SAE.

CONCLUSIONS

This study shows that therapeutic drug monitoring is indicated in patients with a voriconazole-related SAE and that dose adjustment is required if the trough concentration of voriconazole exceeds 5.83 mg/l.

Pharmacology and metabolism of voriconazole and Posaconazole in the treatment of invasive aspergillosis: review of the literature

Invasive fungal infections, predominantly aspergillosis and candidiasis, are among the most important causes of morbidity and mortality in immunocompromised patients. Primarily, patients with acute leukemia undergoing myelosuppressive chemotherapy and allogeneic stem cell transplant recipients are affected. Up to 60% of patients with invasive aspergillosis, the most common invasive mycosis among patients with hematologic malignancies, may still die of their infection, once it has become clinically overt. The spectrum of antifungal agents for clinical use now has expanded over the past ten years and includes the novel class of the echinocandins and two newer generation triazoles with an extended spectrum of activity against a wide range of fungal pathogens. This review will address pharmacological characteristics of the two broad-spectrum antifungal azoles, voriconazole and Posaconazole, which are important for their proper use in clinical practice.

A rescue therapy with a combination of caspofungin and liposomal amphotericin B or voriconazole in children with haematological malignancy and refractory invasive fungal infections

Combination treatment of paediatric invasive fungal infections (IFIs) has rarely been reported. A total of 17 children with 19 IFI episodes were enrolled in the study. The median age of the patients was 5.3 (range 0.5-17) years. IFI was classified as proven in 4, probable in 12 and possible in 3 episodes. These patients received empiric antifungal treatment, which consisted of liposomal amphotericin B (LAmB) monotherapy for a median duration of 12 days (range 3-69 days). All patients were refractory to LAmB; therefore, caspofungin was added to the therapy in 11 patients. In the remaining six patients, LAmB was ceased and a combination of caspofungin and voriconazole was started. Among the patients who received caspofungin + LAmB, four did not show favourable response and the combination was switched to caspofungin + voriconazole. The median (range) and total duration of the therapy were 7 (3-14) days and 91 patient days for LAmB + caspofungin combination and 49 (7-126) days and 516 patient days for caspofungin + voriconazole combination. We found a favourable response rate of 68.4% in 16 proven or probable IFI episodes. Twelve-week survival rate of these patients was 75%. No serious side effect was observed among the patients. Our data suggest that combination antifungal therapy is safe and effective in children with haematological malignancies.

[Auditory hallucinations due to voriconazole: Illustration by plasma monitoring]

Voriconazole is a second-generation azole antifungal that is widely indicated in the treatment of invasive aspergillosis. It is generally well tolerated. It has nevertheless numerous side effects like hepatotoxicity, photosensitivity, skin rashes, and visual disturbances. Hallucinations were also reported as side effects to voriconazole but auditory hallucinations were rarely reported and seem to be related to toxic voriconazole blood levels. We report, herein, a case of auditory hallucination with monitoring of voriconazole plasma concentration during hallucination and after its disappearance. A 38-year-old man was treated with intravenously voriconazole for a pulmonary aspergillosis. Seven days after the initiation of voriconazole, the patient presented a sudden history of auditory hallucination associated to incoherence and temporo-spatial disorientation. Therapeutic drug monitoring of voriconazole showed a plasmatic residual concentration (C0) of 7.5μg/mL (therapeutic interval: 1.4-1.8μg/mL) and a pic concentration (Cmax) of 9.83μg/mL (therapeutic interval: 2.1-4.8μg/ml). Voriconazole was then stopped and, two days later, symptomatology completely disappeared and at the same time levels of voriconazole decreased (C0=0.11μg/mL and Cmax=2.17μg/mL). We concluded in our case that the patient's auditory hallucinations were caused by voriconazole treatment. In fact, the sudden onset of hallucinations was concomitant with high plasmatic voriconazole levels, and since the medication was stopped, an important decrease of voriconazole levels was observed which was associated with a sudden disappearance of the auditory hallucinations.

Observational study of the clinical efficacy of voriconazole and its relationship to plasma concentrations in patients

Voriconazole is approved for treating invasive fungal infections. We examined voriconazole exposure-response relationships for patients from nine published clinical trials. The relationship between the mean voriconazole plasma concentration (C(avg)) and clinical response and between the free C(avg)/MIC ratio versus the clinical response were explored using logistic regression. The impact of covariates on response was also assessed. Monte Carlo simulation was used to estimate the relationship between the trough concentration/MIC ratio and the probability of response. The covariates individually related to response were as follows: study (P < 0.001), therapy (primary/salvage, P < 0.001), primary diagnosis (P < 0.001), race (P = 0.004), baseline bilirubin (P < 0.001), baseline alkaline phosphatase (P = 0.014), and pathogen (yeast/mold, P < 0.001). The C(avg) for 72% of the patients was 0.5 to 5.0 μg/ml, with the maximum response rate (74%) at 3.0 to 4.0 μg/ml. The C(avg) showed a nonlinear relationship to response (P < 0.003), with a lower probability at the extremes. For patients with C(avg) < 0.5 μg/ml, the response rate was 57%. The lowest response rate (56%) was seen with a C(avg) ≥ 5.0 μg/ml (18% of patients) and was associated with significantly lower mold infection responses compared to yeasts (P < 0.001) but not with voriconazole toxicity. Higher free C(avg)/MIC ratios were associated with a progressively higher probability of response. Monte Carlo simulation suggested that a trough/MIC ratio of 2 to 5 is associated with a near-maximal probability of response. The probability of response is lower at the extremes of C(avg). Patients with higher free C(avg)/MIC ratios have a higher probability of clinical response. A trough/MIC ratio of 2 to 5 can be used as a target for therapeutic drug monitoring.

Voriconazole in the management of nosocomial invasive fungal infections

Voriconazole is a new triazole developed for the treatment of life-threatening fungal infections. The drug is available for both oral and intravenous administration; the oral formulation has excellent bioavailability. The side-effect profile of voriconazole presents an acceptable safety and tolerability spectrum: transient visual disturbances, liver enzyme abnormalities, and skin rashes are the most frequently reported side effects but rarely lead to discontinuation. The potential for drug–drug interactions is high, because of its extensive hepatic metabolism. Careful attention to dosage is required, and serum levels and the effects of interacting drugs should be monitored. Review of 25 470 isolates of yeasts and 3216 isolates of filamentous fungi showed voriconazole to have broad-spectrum activity against pathogenic yeasts including intrinsically fluconazole-resistant isolates such as Candida krusei, dimorphic fungi, and opportunistic moulds like Aspergillus spp, amphotericin-B-resistant Aspergillus terreus, Fusarium spp, and Scedosporium apiospermum. It displays excellent clinical efficacy in patients with fluconazole-resistant and -susceptible Candida infections, invasive bone and central nervous system aspergillosis, and various refractory fungal infections. Voriconazole has been approved by the US Food and Drug Administration and by the European Medicines Agency for the treatment of invasive aspergillosis, serious infections caused by Fusarium and S. apiospermum, fluconazole-resistant invasive Candida infections, and candidemia in nonneutropenic patients.

[Level of evidence for therapeutic drug monitoring of voriconazole]

Voriconazole is a major antifungal drug with activity against endemic fungi, Candida and Aspergillus species in immunocompromised patients. Voriconazole has a good bioavailability, an high protein binding percentage in plasma and is metabolized in liver via CYP2C19. It presents important neuro- and hepatotoxicities. Some studies determined trough concentrations of voriconazole in plasma using liquid chromatography coupled with UV or tandem mass detection. These studies showed a relationship between trough concentrations of voriconazole and efficacy or toxicity. Indeed, some studies reported a relationship between a lack of clinical response and concentrations below 1 or 2 μg/mL according to the localization of infection, while toxicities are frequently observed at concentrations above 5 μg/mL. Some particular populations will have to be taken into account such as children, patients with hemodialysis-dependent renal deficiency or hepatic insufficiency, cystic fibrosis patients or those treated concomitantly with interfering drugs. According to our survey, therapeutic drug monitoring of voriconazole appears recommended. However, controlled studies are still necessary to validate it prospectively and to evaluate pharmacokinetically-based methods proposed for individual dose adjustment.

Fungal infections in severe acute pancreatitis

Severe acute pancreatitis (SAP) is associated with significant morbidity and mortality. The majority of deaths related to SAP are the result of infectious complications. Although bacterial infections are most commonly encountered, fungal infections are increasingly being recognized. Candida is the most common fungal infection. The occurrence of fungal infection in patients with acute pancreatitis adversely affects the clinical course, leading to a higher incidence of systemic complications, and possibly mortality as well. Important risk factors for fungal infection in patients with acute pancreatitis include broad-spectrum antibiotics, prolonged hospitalization and surgical/endoscopic interventions, use of total parenteral nutrition, and mechanical ventilation. Patients with higher severity of pancreatitis are at a greater risk. The pathogenesis of fungal infection in patients with acute pancreatitis is multifactorial. Translocation of microorganisms across the gut epithelium, lymphocyte dysfunction, and the virulence of the invading microorganisms play important roles. Histological demonstration of fungi remains the gold standard of diagnosis, but a positive biopsy is rarely obtained. The role of biomarkers in the diagnosis is being investigated. As early diagnosis and treatment can lead to improved outcome, a high index of suspicion is required for prompt diagnosis. Limiting the use of broad-spectrum antibiotics, early introduction of enteral nutrition, and timely change of vascular catheters are important preventive strategies. The role of antifungal prophylaxis remains controversial. Surgical necrosectomy with antifungal therapy is the most widely used treatment approach. Clinical trials on antifungal prophylaxis are needed, and indications for surgical intervention need to be clearly defined.

Long-term visual safety of voriconazole in adult patients with paracoccidioidomycosis

BACKGROUND

Voriconazole is an antifungal agent with in vitro activity and clinical efficacy against yeasts, molds, and dimorphic fungi (eg, Paracoccidioides brasiliensis). The safety profile of voriconazole includes transient visual adverse events (VAEs) that resolve while undergoing treatment or after its discontinuation.

OBJECTIVE

The goal of this study was to assess the long-term (ie, 6-12 months) visual safety of voriconazole in adult patients with paracoccidioidomycosis.

METHODS

Ophthalmic data were prospectively collected as part of a multicenter, open-label, comparative study. Patients aged ≥18 years with paracoccidioidomycosis were randomized in a 2:1 ratio to receive either voriconazole (200 mg BID orally, after the loading dose of 400 mg BID on day 1) or itraconazole (100 mg BID orally, with no loading dose). Patients were expected to receive treatment for a minimum of 6 months, or longer if needed as determined by the investigator (maximum duration, 1 year). Visual function tests and safety assessments were performed at baseline, week 12, week 24, end of treatment (EOT), and 8 weeks post-EOT. Ophthalmic examinations included visual acuity, color vision, contrast sensitivity, visual field, funduscopy, and slit lamp biomicroscopy. Treatment compliance was monitored via pill counts at each study visit.

RESULTS

Thirty-five patients (mean age, 48 years; 96.2% male; 83.0% white) were randomized to receive voriconazole and 18 to receive itraconazole. Fourteen voriconazole-treated patients received >6 months of treatment (median, 169 days). Efficacy and overall safety results have been published previously. Sixteen voriconazole-treated patients and 2 itraconazole-treated patients experienced drug-related VAEs; none was considered serious or severe or led to dose reductions or resulted in discontinuation. Overall, visual examination results were not clinically significantly different between patients treated with voriconazole or itraconazole. There was no apparent relationship between changes in visual function test results and the occurrence of VAEs in either treatment group.

CONCLUSION

Clinical assessment in this study found no evidence of an effect of voriconazole on long-term visual function in these adult patients with paracoccidioidomycosis.

Therapeutic drug monitoring of voriconazole and posaconazole

Despite the availability of newer antifungal agents, invasive fungal diseases remain a leading cause of morbidity and mortality in immunocompromised patients. Voriconazole and posaconazole are two extended-spectrum triazoles indicated for treatment and prophylaxis of invasive fungal diseases. Recently, there has been increased interest in the utility of therapeutic drug monitoring to optimize safety and efficacy of antifungals in an attempt to improve patient outcomes. We reviewed the pharmacokinetic and pharmacodynamic characteristics of voriconazole and posaconazole in the context of clinical indications for therapeutic drug monitoring. In addition, the most recent evidence examining the relationship between serum concentrations of voriconazole and posaconazole and their efficacy or toxicities was evaluated. This information was then integrated to formulate recommendations for use of therapeutic drug monitoring in clinical settings.

[Guidelines for the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC). 2011 Update]

The guidelines on the treatment of invasive fungal disease by Aspergillus spp. and other fungi issued by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) are presented. These recommendations are focused on four clinical categories: oncology-haematology patients, solid organ transplant recipients, patients admitted to intensive care units, and children. An extensive review is made of therapeutical advances and scientific evidence in these settings. These guidelines have been prepared according the SEIMC consensus rules by a working group composed of specialists in infectious diseases, clinical microbiology, critical care medicine, paediatrics and oncology-haematology. Specific recommendations on the prevention of fungal infections in these patients are included.