Efficacy of voriconazole in a murine model of cryptococcal central nervous system infection

Voriconazole plus flucytosine is not superior to amphotericin B deoxycholate plus flucytosine as an induction regimen for cryptococcal meningitis treatment

BACKGROUND

The efficacy and side effects of voriconazole plus 5-flucytosine (Vori + 5-FC) versus amphotericin B deoxycholate plus 5-flucytosine (AmBd + 5-FC) as an induction treatment for cryptococcal meningitis are unknown.

METHODS

Forty-seven patients treated with Vori + 5-FC and 92 patients treated with AmBd + 5-FC were included in the current study after propensity score matching (PSM) at a ratio of 1:2. Two-week laboratory test results and 90-day mortality were compared between the two groups.

RESULTS

After 2 weeks of induction treatment, the CSF Cryptococcus sterile culture rate was 57.1% in the Vori + 5-FC group and 76.5% in the AmBd + 5-FC group (p = .026). No difference was found in the normalization of CSF indicators (glucose, total protein, intracranial pressure and India ink sterile rate) between the two groups. Both the Vori + 5FC regimen and AmBd + 5-FC regimen obviously decreased haemoglobin concentrations, platelet counts and serum potassium levels (all p ≤ .010). Notably, the Vori + 5FC regimen did not influence serum creatinine levels (p = .263), while AmBd + 5FC increased serum creatinine levels (p = .019) after 2-week induction treatment. The Vori + 5-FC group and AmBd + 5-FC group had similar 90-day cumulative survival rates (89.9% vs. 87.8%, p = .926).

CONCLUSION

The Vori + 5-FC regimen was associated with low 2-week CSF sterile culture and was not superior to AmBd + 5-FC as induction therapy in terms of the 90-day cumulative survival rate of CM patients.

Amphotericin B plus fluorocytosine combined with voriconazole for the treatment of non-HIV and non-transplant-associated cryptococcal meningitis: a retrospective study

Background

Our previous study explored Amphotericin B (AMB) plus 5-flucytosine (5-FC) combined with fluconazole (FLU) therapy in the induction period, which seemed to be better than the previous AMB + 5-FC antifungal therapy in non-HIV and non-transplant-associated CM. However, based on our clinical finding, the outcomes of some CM patients who received AMB plus 5-FC combined with FLU antifungal therapy were still poor. Therefore, we need to explore new antifungal methods in non-HIV and non-transplant-associated CM during the induction period.

Methods

Clinical data from 148 patients admitted to the Third Affiliated Hospital of Sun Yat Sen University from January 2011 to December 2020 were collected. These patients were stratified based on antifungal treatment methods in the induction period (group I with AMB + 5-FC + VOR, group II with AMB + 5-FC + FLU, group III with AMB + 5-FC).

Results

The first hospitalization time of Group I (median: 25 days, IQR: 20–34.5) was significantly shorter than that of Group II (median: 43 days, IQR: 29–62) (p < 0.001) and Group III (median: 50.5 days, IQR: 43–77.5) (p < 0.001). After 2 weeks of follow-up, Group I (26/49) had more patients reaching CSF clearance (p = 0.004) than Group II (18/71) and Group III (7/28). In multivariable analysis, Group II (OR: 3.35, 95%CI 1.43–7.82, p = 0.005) and Group III (OR: 3.8, 95%CI 1.23–11.81, p = 0.021) were associated with higher risk about CSF clearance failure at 2 weeks follow-up than Group I. After 10 weeks of follow-up, the incidence of hypokalemia in Group I was significantly lower than that in Group II (p = 0.003) and Group III (p = 0.004), and the incidence of gastrointestinal discomfort in Group I was significantly lower than that in Group II (p = 0.004).

Conclusion

AMB plus 5-FC combined with VOR may rapidly improve clinical manifestation, decrease CSF OP and clear the cryptococci in CSF during the early phase, substantially shorten the hospitalization time, and reduce the incidences of hypokalemia and gastrointestinal discomfort.

Comparison of amphotericin B deoxycholate in combination with either flucytosine or fluconazole, and voriconazole plus flucytosine for the treatment of HIV-associated cryptococcal meningitis: a prospective multicenter study in China

BACKGROUND

The most appropriate alternative to induction therapy for HIV-associated cryptococcal meningitis (CM) remains unclear when standard treatment is unavailable, inaccessible, intolerable, or ineffective.

METHODS

A prospective, multi-centre cohort study was conducted to analyze the data of 156 HIV-infected patients with CM who were treated with amphotericin B deoxycholate (AmB-D) + flucytosine (5FC), voriconazole (VCZ) + 5FC, or AmB-D + Fluconazole (Flu) as induction regimens. Clinical efficacy, cumulative mortality, and adverse effects were compared among the three treatment groups.

RESULTS

Fewer deaths occurred by week 4 and week 10 among patients receiving AmB-D + 5FC than among those receiving AmB-D + Flu [4 (5.1%) vs. 8 (16.0%) deaths by week 4; hazard ratio, 1.8; 95% confidence interval [CI], 1.0 to 3.3; p = 0.039; and 8 (10.3%) vs. 14 (28.0%) deaths by week 10; hazard ratio, 1.8; 95% CI, 1.1 to 2.7; p = 0.008, respectively]. AmB-D plus 5FC was found to result in significantly higher rates of cerebrospinal fluid (CSF) culture sterility (57.6% vs. 34% by week 2; 87.9% vs. 70% by week 10; p < 0.05 for both comparisons). However, the differences in CSF culture sterility and mortality between the VCZ + 5FC group and the AmB-D + 5FC group were not statistically significant. VCZ plus 5FC had a significantly advantageous effect on the incidence of new AIDS-defining illness and length of hospital stay, compared with AmB-D plus 5FC. Laboratory adverse events (grade 3 or 4), such as severe anemia, were less frequent with VCZ + 5FC use than with AmB-D combined with 5FC or Flu use.

CONCLUSION

Our results suggest that AmB-D combined with 5FC remains the more efficacious induction regimen compared to AmB-D plus Flu, and that VCZ + 5FC might be a potential alternative when the standard regimen is not readily available, accessible, tolerated, or effective.

CLINICAL TRIALS

Registration number, ChiCTR1900021195. Registered 1 February 2019, http://www.chictr.org.cn/showproj.aspx?proj=35362 .

Kolliphor® HS 15-cyclodextrin Complex for the Delivery of Voriconazole: Preparation, Characterization, and Antifungal Activity

BACKGROUND

This study aimed to reduce the amount of sulfobutylether-β-cyclodextrin (SBECD) used in the marketed voriconazole injections to meet the clinical needs of patients with moderate-to-severe renal impairment (creatinine clearance rate <50 mL/min).

OBJECTIVE

This study found that the surfactant Kolliphor® HS 15 (HS 15) and SBECD had significant synergistic effects on solubilizing voriconazole, and a novel voriconazole complex delivery system (VRC-CD/HS 15) was established.

METHODS

The complex system was characterized, and its antifungal activity was studied by dynamic light scattering, dialysis bag method, disk diffusion, and broth microdilution.

RESULTS

Compared with the control, its encapsulation efficiency (90.07±0.48%), drug loading (7.37±0.25%) and zeta potential (-4.36±1.37 mV) were increased by 1.54%, 41.19%, and 296.36%, respectively; its average particle size (13.92±0.00 nm) was reduced by 15.69%, so the complex system had better stability. Simultaneously, its drug release behavior was similar to that of the control, and it was a first-order kinetic model. Antifungal studies indicated that the complex system had noticeable antifungal effects. With the increase of drug concentration, the inhibition zone increased. The minimum inhibitory concentrations of the complex system against Cryptococcus neoformans, Aspergillus niger and Candida albicans were 0.0313 μg/mL, 1 μg/mL and 128 μg/mL, respectively.

CONCLUSION

It showed a significant inhibitory effect on C. neoformans and had a visible therapeutic effect on Kunming mice infected with C. neoformans. Consequently, VRC-CD/HS 15 had better physicochemical properties and still had an apparent antifungal effect, and was promising as a potential alternative drug for clinical application.

Efficacy of voriconazole in vitro and in invertebrate model of cryptococcosis

Cryptococcosis is a common opportunistic infection in patients with advanced HIV infection and may also affect immunocompetent patients. The available antifungal agents are few and other options are needed for the cryptococcosis treatment. In this work, we first analyzed the virulence of twelve C. neoformans and C. gattii strains assessing capsule thickness, biofilms formation, and survival and morbidity in the invertebrate model of Galleria mellonella and then we evaluated the antifungal activity of voriconazole (VRC) in vitro and in vivo also using G. mellonella. Our results showed that all Cryptococcus spp. isolates were able to produce capsule and biofilms, and were virulent using G. mellonella model. The VRC has inhibitory activity on planktonic cells with MIC values ranging from 0.03 to 0.25 μg/mL on Cryptococcus spp.; and these isolates were more tolerant to fluconazole (ranging from 0.25 to 16 μg/mL), the triazol agent often recommended alone or in combination with amphotericin B in the cryptococcosis therapy. In contrast, mature biofilms were less susceptible to the VRC treatment. The VRC (10 or 20 mg/kg) treatment of infected G. mellonella larvae significantly increased the larval survival when compared to the untreated group for the both Cryptococcus species and significantly decreased the fungal burden and dissemination in the larval tissue. Our findings corroborate with the literature data, supporting the potential use of VRC as an alternative for cryptococcosis treatment. Here, we emphasize the use of G. mellonella larval model as an alternative animal model for studies of antifungal efficacy on mycosis, including cryptococcosis.

Combined antifungal therapy against systemic murine infections by rare Cryptococcus species

Cryptococcus albidus and Cryptococcus laurentii are uncommon species of this genus that in recent decades have increasingly caused opportunistic infections in humans, mainly in immunocompromised patients; the best therapy for such infection being unknown. Using a murine model of systemic infection by these fungi, we have evaluated the efficacy of amphotericin B (AMB) at 0.8 mg/kg, administered intravenously, fluconazole (FLC) or voriconazole (VRC), both administered orally, at 25 mg/kg and the combination of AMB plus VRC against three C. albidus and two C. laurentii strains. All the treatments significantly reduced the fungal burden in all the organs studied. The combination showed a synergistic effect in the reduction in fungal load, working better than both monotherapies. The histopathological study confirmed the efficacy of the treatments.

Efficacy and toxicity evaluation of new amphotericin B micelle systems for brain fungal infections

The aim of this work is to study the micelle systems of amphotericin B (AmB) and surfactant sodium deoxycholate (NaDC) as possible formulations to treat brain fungal infections. Fungizone(®) and Ambisome(®) were used as AmB references. The particle size, aggregation state, toxicity and efficacy of AmB:NaDC micelles were studied with increasing proportions of NaDC. Differences in the size and aggregation state of the reference formulations and micellar NaDC formulations might explain the differences in their distribution and therefore in their toxicity and efficacy. AmB:NaDC 1:0.8 and 1:1.5 nano-sized micelle systems showed a poly-aggregated form of AmB and small mean particle size (450-750 nm). The AmB:NaDC 1:0.8 and AmB:NaDC 1:1.5 micelle systems studied showed an 8-fold lower toxicity than Fungizone(®). Efficacy was examined in a murine candidiasis model by determining the survival rate and tissue burden reduction in kidneys and brain. The AmB:NaDC 1:1.5 micellar system at 5mg/kg of AmB and the highest amount of NaDC (7.5 mg/kg) presented a good survival rate, and induced a major clearance of brain infection. The new AmB:NaDC 1:1.5 nano-sized micelle system is a promising formulation with a good efficacy/toxicity ratio, which can be attributed to its particle size, AmB aggregation state and NaDC content.

The development of animal infection models and antifungal efficacy assays against clinical isolates of Trichosporon asahii, T. asteroides and T. inkin

The present study developed Galleria mellonella and murine infection models for the study of Trichosporon infections. The utility of the developed animal models was demonstrated through the assessment of virulence and antifungal efficacy for 7 clinical isolates of Trichosporon asahii, T. asteroides and T. inkin. The susceptibility of the Trichosporon isolates to several common antifungal drugs was tested in vitro using the broth microdilution and the E-test methods. The E-test method depicted a lower minimal inhibitory concentration (MIC) for amphotericin and a slightly higher MIC for caspofungin, while MICs observed for the azoles were different but comparable between both methods. All three Trichosporon species established infection in both the G. mellonella and immunosuppressed murine models. Species and strain dependent differences were observed in both the G. mellonella and murine models. T. asahii was demonstrated to be more virulent than the other 2 species in both animal hosts. Significant differences in virulence were observed between strains for T. asteroides in the murine model. In both animal models, fluconazole and voriconazole were able to improve the survival of the animals compared to the untreated control groups infected with any of the 3 Trichosporon species. In G. mellonella, amphotericin was not able to reduce mortality in any of the 3 species. In contrast, amphotericin was able to reduce murine mortality in the T. asahii or T. inkin models, respectively. Hence, the developed animal infection models can be directly applicable to the future deeper investigation of the molecular determinants of Trichosporon virulence and antifungal resistance.

Factors of poor prognosis of visceral leishmaniasis among children under 12 years of age. A retrospective monocentric study in Belo Horizonte, State of Minas Gerais, Brazil, 2001-2005

INTRODUCTION

A major concern with the visceral leishmaniasis (VL) is its high lethality rate, even with proper treatment. Low age, prior malnutrition, disease duration prior to diagnosis, severe anemia, fever for more than 60 days, diarrhea and jaundice are known poor prognostic factors. The goals of this study are to describe the clinical and laboratory characteristics of VL among children under 12 years of age and to identify the factors associated with VL poor outcome.

METHODS

Two hundred and fifty children under 12 years of age with confirmed VL admitted to Hospital João Paulo II (FHEMIG), Belo Horizonte, Brazil, between January 2001 and December 2005 were evaluated retrospectively. The primary outcome was the poor clinical evolution: sepsis, and/or pneumonia, and/or urinary tract infection, and/or of bleeding (expect epistaxis), and/or severe neutropenia (neutrophil < 500 cells/mm3). Odds ratio (crude and adjusted) and its 95% confidence interval for each variable were calculated. Values less than 0.05 were considered significant.

RESULTS

Average age was 3.3 years (3.6 months-11.6 years), 71.2% were younger than 5 years and 47.2% lived in Metropolitan Area of Belo Horizonte. The mean fatality rate was 3.6%. Sixty-six (26.4%) patients presented poor evolution. After a multivariate analysis, age <18 months, abnormal respiratory physical examination on hospital admission, and platelets <85,000/mm3 remained associated with increased chance of poor evolution.

CONCLUSIONS

The results suggest that patients aged between 12 and 18 months, with platelet counts below 85,000/mm3, and respiratory abnormalities at admission should be considered potentially severe.

Successful salvage therapy of refractory HIV-related cryptococcal meningitis with the combination of liposomal amphotericin B, voriconazole, and recombinant interferon-γ

We present 2 cases of HIV-related cryptococcal meningitis, persisting after 3 and 9 months, respectively, of standard treatment. Both patients were treated successfully with a salvage regimen consisting of the combination of liposomal amphotericin B (3 mg/kg), intravenous voriconazole, and subcutaneous recombinant interferon γ-1b (200 μg thrice weekly). Voriconazole was administered at an increased dose (5 mg/kg, twice daily) to overcome interactions with co-administered ritonavir. In both patients, resolution of clinical signs and symptoms, as well as sterilization of cerebrospinal fluid cultures occurred after 10 weeks of salvage therapy. No major side effects were encountered. At the end of treatment, both patients were placed on maintenance therapy with oral fluconazole; no recurrence has been observed after 4 years of follow-up.

Efficacy of intrathecal administration of liposomal amphotericin B combined with voriconazole in a murine model of cryptococcal meningitis

Meningitis is one of the most fatal manifestations of cryptococcosis, even with specific treatment. Combination of a prompt diagnosis and appropriate therapy are critical to reduce the fungal load and the inflammatory response effects of the proliferation of yeast into the central nervous system (CNS). Mice with experimental acute meningitis caused by Cryptococcus neoformans were treated with liposomal amphotericin B (L-AmB) administered intrathecally (i.t.c.) at 0.006 mg/kg weekly or intravenously (i.v.) at 10 mg/kg daily or with voriconazole (VCZ) administered orally at 30 mg/kg per dose twice daily or with combinations of both drugs, i.e. L-AmB i.t.c.+VCZ or L-AmB i.v.+VCZ at the same doses as used in the monotherapies. All treatments significantly increased the survival of animals in comparison with the control group, with VCZ being less effective in comparison with all other treatments (P ≤ 0.012). All treatments, with the exception of VCZ (P=0.533), reduced fungal burdens in the brain in comparison with controls. The combination of L-AmB i.t.c.+VCZ showed a synergistic effect in the reduction of fungal load that was significantly superior to any tested therapy (P ≤ 0.039). Histologically, untreated animals showed a marked inflammatory response with massive fungal cells in the meninges, whilst treated animals showed a variable number of fungal cells in the CNS, with the exception of animals receiving L-AmB i.t.c.+VCZ in which neither yeasts nor inflammation were observed.

Voriconazole, combined with amphotericin B, in the treatment for pulmonary cryptococcosis caused by C. neoformans (serotype A) in mice with severe combined immunodeficiency (SCID)

Cryptococcosis is a subacute or chronic systemic mycosis with a cosmopolitan nature, caused by yeast of the genus Cryptococcus neoformans. The model of systemic cryptococcosis in mice with severe combined immunodeficiency (SCID) is useful for immunological and therapeutic study of the disease in immunodeficient hosts. Amphotericin B, fluconazole and flucytosine are the drugs most commonly used to treat cryptococcosis. Voriconazole is a triazole with high bioavailability, large distribution volume, and excellent penetration of the central nervous system. The objective of this study was to evaluate treatment with amphotericin B (AMB), voriconazole (VRC), and AMB, used in combination with VRC, of experimental pulmonary cryptococcosis in a murine model (SCID). The animals were inoculated intravenously (iv) with a solution containing 3.0 × 10(5) viable cells of C. neoformans ATCC 90112, (serotype A). Treatments were performed with amphotericin B (1.5 mg/kg/day), voriconazole (40.0 mg/kg/day) and AMB (1.5 mg/kg/day) combined with VRC (40.0 mg/kg/day); began 1 day after the initial infection; were daily; and lasted 15 days. Evaluations were performed using analysis of the survival curve and isolation of yeast in the lung tissue. There was a significant increase in survival in groups treated with AMB combined with VRC, compared with the untreated group and groups receiving other treatments (P < 0.05). In the group treated only with VRC and AMB combined with VRC, there was a significant reduction (P < 0.05) in the isolation of C. neoformans in lung tissue. Amphotericin B combined with voriconazole may be an effective alternative to increasing survival and may reduce yeast in the lung tissue of mice with pulmonary cryptococcosis and SCID.

Comparison of the early fungicidal activity of high-dose fluconazole, voriconazole, and flucytosine as second-line drugs given in combination with amphotericin B for the treatment of HIV-associated cryptococcal meningitis

BACKGROUND

HIV-associated cryptococcal meningitis is associated with an estimated 600 000 deaths worldwide per year. Current standard initial therapy consists of amphotericin B (AmB) plus flucytosine (5-FC), but 5-FC remains largely unavailable in Asia and Africa. Alternative, more widely available, and/or more effective antifungal combination treatment regimens are urgently needed.

METHODS

Eighty HIV-seropositive, antiretroviral naive patients presenting with cryptococcal meningitis were randomized to 4 treatment arms of 2 weeks duration: group 1, AmB (0.7-1 mg/kg) and 5-FC (25 mg/kg 4 times daily); group 2, AmB (0.7-1 mg/kg) and fluconazole (800 mg daily); group 3, AmB (0.7-1 mg/kg) and fluconazole (600 mg twice daily); and group 4, AmB (0.7-1 mg/kg) and voriconazole (300 mg twice daily). The primary end point was the rate of clearance of infection from the cerebrospinal fluid (CSF) or early fungicidal activity (EFA), as determined by results of serial, quantitative CSF cryptococcal cultures.

RESULTS

There were no statistically significant differences in the rate of clearance of cryptococcal colony-forming units (CFU) in CSF samples among the 4 treatment groups; the mean (±standard deviation) EFA for treatment groups 1, 2, 3, and 4 were -0.41 ± 0.22 log CFU/mL CSF/day, -0.38 ± 0.18 log CFU/mL CSF/day, -0.41 ± 0.35 log CFU/mL CSF/day, and -0.44 ± 0.20 log CFU/mL CSF/day, respectively. Overall mortality was 12% (9 of 78 patients died) at 2 weeks and 29% (22 of 75 patients died) at 10 weeks, with no statistically significant differences among groups. There were few laboratory abnormalities related to the second agents given; in particular, there were no statistically significant (≥grade 3) increases in alanine transaminase level or decreases in neutrophil count.

CONCLUSIONS

There was no statistically significant difference in EFA between AmB in combination with fluconazole and AmB plus 5-FC for the treatment of HIV-associated cryptococcal meningitis. AmB plus fluconazole (800-1200 mg/day) represents an immediately implementable alternative to AmB plus 5-FC. AmB plus voriconazole is an effective alternative combination in patients not receiving interacting medications.

Antifungal therapy in a murine model of disseminated infection by Cryptococcus gattii

We have evaluated the efficacy of posaconazole (PSC), voriconazole (VRC), and amphotericin B (AMB) in a murine model of systemic infection by Cryptococcus gattii using immunocompromised animals and three clinical strains of the fungus. AMB was the most effective drug in prolonging the survival of mice and also in reducing tissue burden in all organs tested. To a lesser degree, VRC at 60 mg/kg of body weight in lung tissue and PSC at 40 mg/kg also in spleen demonstrated good efficacy in reducing the fungal load. The PSC and VRC levels in serum and brain tissue, determined by an agar diffusion bioassay method at 4 h after the last dose of the therapy, were above the corresponding MIC values. However, these drugs were not able to reduce the fungal load in brain tissue. Our results demonstrated that PSC and, to a lesser degree, VRC, have fungistatic activity and potential for the treatment of human pulmonary cryptococcosis.

Anidulafungin treatment of candidal central nervous system infection in a murine model

We established a murine model of Candida albicans central nervous system (CNS) infection and evaluated the efficacy of anidulafungin. Ten milligrams/kg/day anidulafungin, amphotericin B, or voriconazole significantly reduced mortality and fungal burden in brain tissue, although amphotericin B and 10 mg/kg/day anidulafungin reduced fungal burden in brain tissue to a greater extent than did voriconazole. This suggests a potential role for anidulafungin in the treatment of candidal CNS infection.

Efficacy of triazoles in a murine disseminated infection by Candida krusei

We evaluated the efficacies of posaconazole and voriconazole in comparison with that of amphotericin B in a systemic murine infection by Candida krusei. Posaconazole at 50 mg/kg/day and voriconazole at 40 and 60 mg/kg/day prolonged survival and reduced the fungal tissue burden in the kidneys of mice similarly to amphotericin B at 1.5 mg/kg/day and liposomal amphotericin B at 10 mg/kg/day. None of the treatments tested completely resolved the infection.

Long-Term Efficacy and Safety of TDM-Assisted Combination of Voriconazole plus Efavirenz in an AIDS Patient with Cryptococcosis and Liver Cirrhosis

Objective

To report the efficacy, tolerability, and pharmacokinetic effects of combined voriconazole and efavirenz treatment administered at therapeutic drug monitoring (TDM)–based adjusted doses to a patient with AIDS, cryptococcosis, and mild liver cirrhosis.

Case Summary

A 40-year-old man with AIDS (hemophiliac, antiretroviral-naïve, plasma HIV-RNA = 290,000 copies/mL, CD4+ lymphocytes = 0), hepatitis C virus–related liver cirrhosis (Child-Pugh class A), and cryptococcal meningitis was failing standard antifungal therapies. He received an antifungal–antiretroviral combination treatment based on the association of voriconazole plus efavirenz. Doses of both drugs were serially adjusted based on their plasma concentrations, which were evaluated at steady-state of each dose combination at least once (week 3.1 or later) as full concentration–time profile (samples collected at 0, 1, 2, 3, 4, 6, 8, 12 h postdose). Adequate concentrations of voriconazole in both plasma and cerebrospinal fluid were obtained and target plasma concentrations of efavirenz were achieved at the final dose adjustment (voriconazole 200 mg twice daily plus efavirenz 300 mg once daily, both administered orally). The patient showed prompt and stable suppression of cryptococcosis and plasma viremia of HIV at long-term follow-up (66 wk), with no significant adverse events.

Discussion

Standard therapies for cryptococcosis in patients with AIDS are often not effective. Voriconazole, despite its promising anticryptococcal efficacy, is currently not approved for cryptococcosis therapy in the US and Europe, nor is it recommended for combination with efavirenz due to the significant pharmacokinetic interactions between the 2 compounds. Thus far, published studies regarding the effects of voriconazole in human cryptococcosis are scarce and none has described the clinical and pharmacokinetic outcomes of a voriconazole/efavirenz combination in patients with AIDS, either with or without liver cirrhosis.

Conlusions

The combination of voriconazole and efavirenz at TDM-assisted doses may represent a valuable therapeutic option in AIDS patients with cryptococcosis and mild liver cirrhosis.

Evaluation of the Neo-Sensitabs diffusion method for determining the antifungal susceptibilities of Cryptococcus gattii isolates, using three different agar media

The Neo-Sensitabs diffusion method was evaluated for determining the antifungal susceptibilities of 30 Cryptococcus gattii isolates to amphotericin B (AMB), fluconazole (FLC), itraconazole (ITC) and voriconazole (VRC). Three different culture media, Müeller-Hinton (MH), RPMI 1640 (RPMI) and Antibiotic medium 3 (AM3), all supplemented with 2% of glucose and 0.5 microg/ml of methylene blue, were tested. The tests were repeated three times on different days at three incubation times (48, 72 and 96 h). Results were compared with those obtained with the CLSI M27-A2 broth microdilution method. The degree of reproducibility of the diffusion test was 100% for VRC and ITC, 98.3-100% for AMB and 43.3-73.3% for FLC. The best reproducibility was observed at 48 h of incubation and no important differences among media were observed at any of the incubation times assayed. Between Neo-Sensitabs and the reference method, VRC showed the best agreement and ITC the worst in all conditions tested (100% and 56.7%, respectively). AMB showed a high agreement between the two methods (93.3% to 96.7%) but Neo-Sensitabs assay failed to detect resistant isolates (discrepancy classified as "very major error") in all times of incubation assayed. Only agreement between both methods for FLC was clearly affected by incubation time and media used, the best results being achieved at 48 h of incubation when MH and RPMI (80.0%, in both media) were used.

Combination therapy of advanced invasive pulmonary aspergillosis in transiently neutropenic rats using human pharmacokinetic equivalent doses of voriconazole and anidulafungin

At present, voriconazole (VOR) is the drug of first choice for treating invasive pulmonary aspergillosis (IPA). However, particularly in advanced stages of disease and in the severely immunocompromised host, the mortality remains substantial. The combination of VOR with an echinocandin may improve the therapeutic outcome. We investigate here whether combining VOR and anidulafungin (ANI) in advanced IPA in transiently neutropenic rats results in a higher therapeutic efficacy. Since VOR is metabolized more rapidly in rodents than in humans, dosage adjustment for VOR is necessary to obtain an area under the plasma concentration-time curve (AUC) in rodents that is equivalent to that of humans. In this study, the pharmacokinetics of VOR and ANI in rats were elucidated, and dosage schedules were applied that produced AUCs similar to those of humans. The developed dose schedules were well tolerated by the rats, without effects on renal and hepatic functions. VOR showed excellent efficacy in early IPA (100% rat survival). In advanced IPA, VOR was less efficacious (50% rat survival), whereas a significant decrease in galactomannan concentrations in lungs and sera was found in surviving rats. ANI administered in advanced IPA resulted in 22% rat survival, and the serum concentrations of fungal galactomannan were slightly but not significantly decreased. The addition of ANI to VOR did not result in significantly increased therapeutic efficacy in advanced IPA, resulting in 67% rat survival and a significant decrease in galactomannan concentration in serum. In conclusion, VOR monotherapy is therapeutically effective in the treatment of advanced-stage IPA and superior to the use of ANI. Combining both agents does not significantly improve the therapeutic outcome.

Pharmacotherapy of yeast infections

The rise of immunocompromised individuals in our society has provoked a significant emergence in the number of patients affected by opportunistic pathogenic yeast. The microorganisms with a major clinical incidence are species from the genera Candida (especially Candida albicans) and Cryptococcus (particularly Cryptococcus neoformans), although there has been a significant increase in other pathogenic yeasts, such as Trichosporon spp. and Rhodotorula spp. In addition, there are an increasing number of patients infected by yeasts that were not previously considered as pathogenic, such as Saccharomyces cerevisiae. The management of these infections is complicated and is highly dependent on the susceptibility profile not only of the species but also of the strain. The available antifungal compounds belong mainly to the polyene, azole and candin families, which show a distinct spectrum of activity. This review summarizes the current knowledge about the use of the main antifungals for treating infections caused by the yeast species with the most significant clinical relevance, including the susceptibility profiles exhibited by these species in vitro.

[In vitro antifungal activity of voriconazole: New data after the first years of clinical experience]

Voriconazole has been developed to meet the increasing need for new and useful antifungal agents for the treatment of invasive mycoses. This review describes the spectrum of voriconazole antifungal activity based on data from in vitro studies published during the last three years. This survey demonstrates that voriconazole has a broad antifungal spectrum against the most common fungal pathogens being its action fungistatic for Candida and fungicidal for Aspergillus and other filamentous fungi. Overall, more than 95% of all Candida isolates tested are susceptible to voriconazole and less than 3% are resistant. Similar or even better activity rates have been described for Aspergillus, Cryptococcus and most of yeasts and moulds of medical importance. We also discuss the limitations related to the azole cross-resistance observed in some Candida glabrata isolates, the poor activity of voriconazole against Scedosporium prolificans, its activity against fungal biofilms and the great potential usefulness of combination of voriconazole with other antifungal drugs.

Voriconazole inhibits melanization in Cryptococcus neoformans

Voriconazole is a triazole antifungal drug that inhibits ergosterol synthesis and has broad activity against yeast and molds. While studying the interaction of voriconazole and Cryptococcus neoformans, we noted that cells grown in the presence of subinhibitory concentrations of voriconazole reduced melanin pigmentation. We investigated this effect systematically by assessing melanin production in the presence of voriconazole, amphotericin B, caspofungin, itraconazole, and fluconazole. Only voriconazole impeded the formation of melanin at subinhibitory concentrations. Voriconazole did not affect the autopolymerization of l-dopa, and 0.5 MIC of voriconazole did affect the gene expression of C. neoformans. However, voriconazole inhibited the capacity of laccase to catalyze the formation of melanin. Hence, voriconazole affects melanization in C. neoformans by interacting directly with laccase, which may increase the efficacy of this potent antifungal against certain pigmented fungi.

El papel del voriconazol en el tratamiento de las micosis emergentes

Voriconazole is a broad-spectrum antifungal drug belonging to triazoles class. Recently, it has been recommended for the treatment of invasive candidiasis in non neutropenic patients. In addition, this drug has showed clinical efficacy in the treatment of fungal infections caused by Candida species other than Candida albicans, and also in several other infections caused by less common fungi, such as Aspergillus terreus, Fusarium and Scedosporium.