Haran T. Schlamm

Voriconazole treatment for less-common, emerging, or refractory fungal infections

Treatments for invasive fungal infections remain unsatisfactory. We evaluated the efficacy, tolerability, and safety of voriconazole as salvage treatment for 273 patients with refractory and intolerant-to-treatment fungal infections and as primary treatment for 28 patients with infections for which there is no approved therapy. Voriconazole was associated with satisfactory global responses in 50% of the overall cohort; specifically, successful outcomes were observed in 47% of patients whose infections failed to respond to previous antifungal therapy and in 68% of patients whose infections have no approved antifungal therapy. In this population at high risk for treatment failure, the efficacy rates for voriconazole were 43.7% for aspergillosis, 57.5% for candidiasis, 38.9% for cryptococcosis, 45.5% for fusariosis, and 30% for scedosporiosis. Voriconazole was well tolerated, and treatment-related discontinuations of therapy or dose reductions occurred for <10% of patients. Voriconazole is an effective and well-tolerated treatment for refractory or less-common invasive fungal infections.

Voriconazole versus a regimen of amphotericin B followed by fluconazole for candidaemia in non-neutropenic patients: a randomised non-inferiority trial.

BACKGROUND Voriconazole has proven efficacy against invasive aspergillosis and oesophageal candidiasis. This multicentre, randomised, non-inferiority study compared voriconazole with a regimen of amphotericin B followed by fluconazole for the treatment of candidaemia in non-neutropenic patients. METHODS Non-neutropenic patients with a positive blood culture for a species of candida and clinical evidence of infection were enrolled. Patients were randomly assigned, in a 2:1 ratio, either voriconazole (n=283) or amphotericin B followed by fluconazole (n=139). The primary efficacy analysis was based on clinical and mycological response 12 weeks after the end of treatment, assessed by an independent data-review committee unaware of treatment assignment. FINDINGS Of 422 patients randomised, 370 were included in the modified intention-to-treat population. Voriconazole was non-inferior to amphotericin B/fluconazole in the primary efficacy analysis, with successful outcomes in 41% of patients in both treatment groups (95% CI for difference -10.6% to 10.6%). At the last evaluable assessment, outcome was successful in 162 (65%) patients assigned voriconazole and 87 (71%) assigned amphotericin B/fluconazole (p=0.25). Voriconazole cleared blood cultures as quickly as amphotericin B/fluconazole (median time to negative blood culture, 2.0 days). Treatment discontinuations due to all-cause adverse events were more frequent in the voriconazole group, although most discontinuations were due to non-drug-related events and there were significantly fewer serious adverse events and cases of renal toxicity than in the amphotericin B/fluconazole group. INTERPRETATION Voriconazole was as effective as the regimen of amphotericin B followed by fluconazole in the treatment of candidaemia in non-neutropenic patients, and with fewer toxic effects. RELEVANCE TO PRACTICE There are several options for treatment of candidaemia in non-neutropenic patients, including amphotericin B, fluconazole, voriconazole, and echinocandins. Voriconazole can be given both as initial intravenous treatment and as an oral stepdown agent.

Imaging findings in acute invasive pulmonary aspergillosis: clinical significance of the halo sign.

BACKGROUND Computed tomography (CT) of the chest may be used to identify the halo sign, a macronodule surrounded by a perimeter of ground-glass opacity, which is an early sign of invasive pulmonary aspergillosis (IPA). This study analyzed chest CT findings at presentation from a large series of patients with IPA, to assess the prevalence of these imaging findings and to evaluate the clinical utility of the halo sign for early identification of this potentially life-threatening infection. METHODS Baseline chest CT imaging findings from 235 patients with IPA who participated in a previously published study were systematically analyzed. To evaluate the clinical utility of the halo sign for the early identification and treatment of IPA, we compared response to treatment and survival after 12 weeks of treatment in 143 patients who presented with a halo sign and in 79 patients with other imaging findings. RESULTS At presentation, most patients (94%) had > or =1 macronodules, and many (61%) also had halo signs. Other imaging findings at presentation, including consolidations (30%), infarct-shaped nodules (27%), cavitary lesions (20%), and air-crescent signs (10%), were less common. Patients presenting with a halo sign had significantly better responses to treatment (52% vs. 29%; P<.001) and greater survival to 84 days (71% vs. 53%; P<.01) than did patients who presented with other imaging findings. CONCLUSIONS Most patients presented with a halo sign and/or a macronodule in this large imaging study of IPA. Initiation of antifungal treatment on the basis of the identification of a halo sign by chest CT is associated with a significantly better response to treatment and improved survival.

Safety and Pharmacokinetics of Oral Voriconazole in Patients at Risk of Fungal Infection: A Dose Escalation Study

The objective of this study was to investigate the safety, tolembility, and pharmacokinetics of oral voriconazole in subjects at high risk of developing fungal infections. This was a multicenter, randomized, double‐blind, double‐dummy, parallel‐group, dose escalation study with a fluconazole active control. Twenty‐four subjects with hematological malignancies, solid tumors, or autologous bone marrow transplants were randomized to receive voriconazole 200 mg q 12 h (n = 9), voriconazole 300 mgq 12 h (n = 9), or fluconazole 400 mg OD(n = 6) for a period of 14 days. Blood samples were taken for the assessment of voriconazole pharmacokinetics in plasma on Days 1 and 14. Using a 200 mgq 12 h dosing regimen, geometric mean voriconazole peak plasma concentrations (Cmsx) were 904 ng/ml on Day 1 and 2996 ng/ml on Day 14. Geometric mean voriconazole exposure, as measured by the area under the curve within a dosing interval (AUCπ, was 4044 and 20308 ng·h/ml on Days 1 and 14, respectively. On Day 1, geometric mean Cmax and AUC were 1.80‐ and 1.94‐fold higher in subjects receiving voriconazole 300 mg q 12 h than in those receiving 200 mg q 12 h. Similarly, on Day 14, geometric mean Cmax and AUC were 1.56‐ and 1.80‐fold greater in the high‐dose group. Although the confidence intervals are large, this trend suggests nonlinearity in pharmacokinetics with respect to dose as seen in healthy volunteers. The absorption of orally administered voriconazole was relatively rapid, with tmax achieved in 1.7 to 3.0 hours. There was a mean 5.4‐ and 5.0‐fold accumulation of voriconazole over the 14‐day study period in the 200 mg and 300 mg q 12 h dose groups, respectively. Voriconazole was generally safe and well tolerated. Mild, reversible visual disturbances were the most commonly reported adverse event but were not associated with treatment discontinuation. No patient developed a breakthrough fungal infection. It was concluded that in thisgroup of patients at risk of fungal infection, voriconazole pharmacokinetics was consistent with that reported in healthy volunteers.

Voriconazole versus itraconazole for antifungal prophylaxis following allogeneic haematopoietic stem-cell transplantation

Antifungal prophylaxis for allogeneic haematopoietic stem‐cell transplant (alloHCT) recipients should prevent invasive mould and yeast infections (IFIs) and be well tolerated. This prospective, randomized, open‐label, multicentre study compared the efficacy and safety of voriconazole (234 patients) versus itraconazole (255 patients) in alloHCT recipients. The primary composite endpoint, success of prophylaxis, incorporated ability to tolerate study drug for ≥100 d (with ≤14 d interruption) with survival to day 180 without proven/probable IFI. Success of prophylaxis was significantly higher with voriconazole than itraconazole (48·7% vs. 33·2%, P < 0·01); more voriconazole patients tolerated prophylaxis for 100 d (53·6% vs. 39·0%, P < 0·01; median total duration 96 vs. 68 d). The most common (>10%) treatment‐related adverse events were vomiting (16·6%), nausea (15·8%) and diarrhoea (10·4%) for itraconazole, and hepatotoxicity/liver function abnormality (12·9%) for voriconazole. More itraconazole patients received other systemic antifungals (41·9% vs. 29·9%, P < 0·01). There was no difference in incidence of proven/probable IFI (1·3% vs. 2·1%) or survival to day 180 (81·9% vs. 80·9%) for voriconazole and itraconazole respectively. Voriconazole was superior to itraconazole as antifungal prophylaxis after alloHCT, based on differences in the primary composite endpoint. Voriconazole could be given for significantly longer durations, with less need for other systemic antifungals.

Review of the Basic and Clinical Pharmacology of Sulfobutylether-β-Cydodextrin (SBECD)

Despite its use in commercially available drugs such as intravenous voriconazole, there is little known in the medical literature about the clinical pharmacology of the solubilizing agent, sulfobutylether-beta-cyclodextrin (SBECD). This paper summarizes all known data on SBECD pharmacokinetics and safety. In animals, volume of distribution approximates extracellular water volume and clearance is determined by the glomerular filtration rate. SBECD does not have any apparent effects on cardiovascular or respiratory systems, nor on autonomic and somatic functions in animals. In 1- and 6-month studies in rats and dogs, the most noteworthy findings were renal tubular vacuolation and foamy macrophages in the liver and lungs. Mild toxicity in the kidney and liver as a consequence of vacuolation occurred in rats at the maximum dose of 3000 mg/kg, which is approximately 50-fold greater than the SBECD dose typically administered in man. Doses up to 1500 mg/kg produced no histopathological evidence of toxicity in dog kidneys. SBECD has also been studied in healthy volunteers and subjects with renal dysfunction. Whereas plasma SBECD levels accumulate in those with renal compromise, there were no deleterious effects on renal function. Nonetheless, serum creatinine levels should be monitored in subjects with renal compromise receiving multiple doses of SBECD.

Strategy of Following Voriconazole versus Amphotericin B Therapy with Other Licensed Antifungal Therapy for Primary Treatment of Invasive Aspergillosis: Impact of Other Therapies on Outcome

BACKGROUND In a previous randomized trial of voriconazole versus amphotericin B deoxycholate for primary therapy of invasive aspergillosis, voriconazole demonstrated superior efficacy and better survival. In that trial, treatment with voriconazole or amphotericin B deoxycholate could be followed with other licensed antifungal therapies (OLAT). Here, we report the impact of OLAT on the outcome of patients with invasive aspergillosis. METHODS Data on dose, duration, and the reason for switching to the first OLAT were analyzed, and outcome at week 12 was assessed. RESULTS Fewer patients in the voriconazole group (52 [36%] of 144) switched to OLAT, compared with patients in the amphotericin B deoxycholate group (107 [80%] of 133). Lipid formulations of amphotericin B were the most common OLAT (38% of patients). Switches were made because of intolerance or insufficient response in 70% for patients in the amphotericin B deoxycholate group, compared with 24% of patients in the voriconazole group. Favorable responses to OLAT in the amphotericin B deoxycholate group occurred in only 19% of patients with initial insufficient response and 38% of patients with intolerance. Salvage therapy with a lipid formulation of amphotericin B after initial treatment with amphotericin B deoxycholate was successful for only 30% of patients (14 of 47). Treatment success among patients randomized to receive amphotericin B, including those whose treatment was switched to OLAT, was 32%, compared with 55% among patients who received voriconazole alone (P<.001). CONCLUSIONS This study highlights the limited efficacy of salvage antifungal therapy, including therapy with lipid formulations of amphotericin B, and demonstrates the importance of effective initial therapy in invasive aspergillosis.

Ocular Manifestations of Candidemia

BACKGROUND Ocular candidiasis is a major complication of candidemia. The incidence, risk factors, and outcome of eye involvement during candidemia are largely unknown. We prospectively studied the ocular manifestations of candidemia in a large, worldwide, randomized multicenter trial that compared voriconazole with amphotericin B followed by fluconazole for the treatment of candidemia. METHODS Nonneutropenic patients with blood cultures positive for Candida species were assigned treatment with voriconazole or with amphotericin B followed by fluconazole in a randomized 2:1 ratio. Dilated fundoscopy was performed in each patient at baseline, on day 7, at 2 and 6 weeks after the end of treatment (EOT), and, if clinically indicated, at 12 weeks after EOT. RESULTS Of 370 patients, 49 had findings consistent with the diagnosis of ocular candidiasis at baseline, and an additional 11 patients developed abnormalities during treatment, totaling 60 patients with eye involvement (16%). Of these patients, probable Candida eye infection was diagnosed in 40 patients (6 with endophthalmitis, 34 with chorioretinitis), and possible Candida eye infection in 20 (all with chorioretinitis). The duration of candidemia was significantly longer in patients with ocular candidiasis (median, 4 days; range, 1-18 days) compared with patients without ocular involvement (median, 3 days; range 1-26 days; log rank, P = .026). Therapy with either voriconazole (44 cases) or amphotericin B followed by fluconazole (16 cases) was successful in 65% of patients; outcome was not evaluable in 32% and was unfavorable in 3%. CONCLUSIONS Ocular involvement occurred in 16% of patients with candidemia; however, endophthalmitis was uncommon (1.6%). Treatment with either voriconazole or amphotericin B followed by fluconazole was successful for ocular candidiasis in most cases with follow-up.

Pharmacokinetics, Safety, and Tolerability of Voriconazole in Immunocompromised Children

ABSTRACT The pharmacokinetics of voriconazole in children receiving 4 mg/kg intravenously (i.v.) demonstrate substantially lower plasma exposures (as defined by area under the concentration-time curve [AUC]) than those in adults receiving the same therapeutic dosage. These differences in pharmacokinetics between children and adults limit accurate prediction of pediatric voriconazole exposure based on adult dosages. We therefore studied the pharmacokinetics and tolerability of higher dosages of an i.v.-to-oral regimen of voriconazole in immunocompromised children aged 2 to <12 years in two dosage cohorts for the prevention of invasive fungal infections. The first cohort received 4 mg/kg i.v. every 12 h (q12h), then 6 mg/kg i.v. q12h, and then 4 mg/kg orally (p.o.) q12h; the second received 6 mg/kg i.v. q12h, then 8 mg/kg i.v. q12h, and then 6 mg/kg p.o. q12h. The mean values for the AUC over the dosing interval (AUCτ) for 4 mg/kg and 6 mg/kg i.v. in cohort 1 were 11,827 and 22,914 ng·h/ml, respectively, whereas the mean AUCτ values for 6 mg/kg and 8 mg/kg i.v. in cohort 2 were 17,249 and 29,776 ng·h/ml, respectively. High interpatient variability was observed. The bioavailability of the oral formulation in children was approximately 65%. The safety profiles were similar in the two cohorts and age groups. The most common treatment-related adverse event was increased gamma glutamyl transpeptidase levels. There was no correlation between adverse events and voriconazole exposure. In summary, voriconazole was tolerated to a similar degree regardless of dosage and age; the mean plasma AUCτ for 8 mg/kg i.v. in children approached that for 4 mg/kg i.v. in adults, thus representing a rationally selected dosage for the pediatric population.

Changes in Causes of Death Over Time After Treatment for Invasive Aspergillosis

Assessment of response to invasive aspergillosis (IA) therapy has been challenging in treatment trials.