REVIEW ARTICLE |
a Department of Immunology and Infectious Diseases, Sydney Children's Hospital, Randwick, New South Wales, Australia
b School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia
c Centre for Children's Cancer and Blood Disorders, Sydney Children's Hospital, Randwick, New South Wales, Australia
| ABSTRACT |
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Key Words: antifungal agents pediatrics mycoses candidiasis aspergillosis neutropenia
Abbreviations: IFIinvasive fungal infection CABconventional amphotericin B deoxycholate ABLCamphotericin B lipid complex ABCDamphotericin B colloidal dispersion RCTrandomized, controlled trial
Invasive fungal infection (IFI) is a significant problem in those at risk. Candida and Aspergillus species are the most frequent fungi responsible for invasive infections in children. Worldwide, the incidence is increasing in at-risk populations.14 Furthermore, the increasing incidence of resistant fungi is creating additional therapeutic challenges.1,58
Despite improvements in supportive care, IFI is still associated with a significant mortality rate and high health care costs.9 In studies published within the last decade, mortality rates in children with candidemia range from 19% to 31%.1015 Invasive aspergillosis in children is associated with even greater mortality: 68% to 77%.1619 A higher mortality rate is seen in those with greater degrees of immunosuppression, particularly after hematopoietic stem cell transplantation.17
Currently, there are 4 classes of drugs for treatment of IFIs: polyenes, triazoles, echinocandins, and nucleoside analogues. The available polyenes include conventional amphotericin B deoxycholate (CAB), liposomal amphotericin B, amphotericin B lipid complex (ABLC), and amphotericin B colloidal dispersion (ABCD). Numerous triazoles have been trialled, including fluconazole, itraconazole, voriconazole, posaconazole, and ravuconazole. Both groups of drugs target ergosterol, a key component of the fungal cell membrane.20 Echinocandins (caspofungin, micafungin, and anidulafungin) are a novel class of antifungal agents that interfere with cell wall biosynthesis.21 Finally, the nucleoside analog flucytosine interferes with nucleotide synthesis.
Differences between children and adults with IFI exist. These differences include predisposing factors, infective organism, and site of infection.16,18,22 Significant pharmacokinetic differences occur between pediatric and adult patients with many antifungal agents. Therefore, there is a need for pediatric-specific data to guide antifungal therapy in children.
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In this review, data on the most frequently encountered clinical problems are presented: antifungal therapy in prolonged fever and neutropenia, candidemia/invasive candidiasis, and invasive aspergillosis. Relative antifungal toxicities are also compared. When pediatric studies have been judged to be insufficient, adult studies have been used to supplement data. Pediatric comparative trial data are listed in Tables 1 and 2; recommended pediatric and adult dosages of antifungal agents are listed in Table 3.
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Prentice et al26 conducted the largest pediatric randomized, controlled trial (RCT) to date. In an RCT that included 202 children with 96 hours of fever and neutropenia that were unresponsive to broad-spectrum antibiotics, liposomal amphotericin B (1 or 3 mg/kg per day) was compared with CAB (1 mg/kg per day). Safety was the primary end point. The study also included 134 adults. Treatment success (fever defervescence without additional antifungal therapy) was observed in 51% of children who received CAB, 64% who received 1 mg/kg per day of liposomal amphotericin B, and 63% who received 3 mg/kg per day of liposomal amphotericin B (P = .22). Although the overall analysis (adults and children inclusive) demonstrated a significant difference in treatment success between CAB and the higher dose of liposomal amphotericin B (49% vs 64%; P = .03), the Kaplan-Meier analysis of time to fever defervescence failed to show any significant difference between these treatment arms.26
In another small trial, CAB (0.8 mg/kg per day) and ABCD (4 mg/kg per day) therapy were compared in 49 children with prolonged fever and neutropenia.27 A composite end point was used to assess treatment success: fever defervescence, survival for at least 7 days after drug cessation, no documented or suspected IFI within 7 days of receipt of the study drug, and no toxicities that required cessation of therapy. The difference in treatment success observed between CAB and ABCD approached significance (41% vs 69%; P = .051), yet the time to fever defervescence was similar with both treatments (P = .654).
Other empiric antifungal trials that compared different formulations of amphotericin B have not included children, or pediatric subgroup analysis was not performed. Adult trials have failed to demonstrate a significant difference in treatment success when CAB (0.60.8 mg/kg per day) is compared with liposomal amphotericin B (3 mg/kg per day) or ABCD (4 mg/kg per day).28,29 Furthermore, a meta-analysis of RCTs that included 1895 patients failed to demonstrate any difference in mortality between CAB and lipid-agent use.30 Fewer breakthrough fungal infections were seen in those receiving liposomal amphotericin B compared with CAB.30 No difference in treatment success was observed when liposomal amphotericin B was compared with ABLC in persistently febrile and neutropenic adults, although the study was insufficiently powered.31
Kim et al32 compared CAB and itraconazole as empiric therapy in 30 neutropenic children. The trial was inadequately powered, and both cohorts were poorly matched for duration of neutropenia. No difference in response rate was observed. A number of trials have compared fluconazole or itraconazole with CAB in neutropenic patients.3336 Only 1 trial was adequately powered,34 and 1 was inclusive of children.35 All subjects were azole naive before the study. No pediatric subgroup analysis was performed. All trials showed that azoles were equally effective as CAB. Voriconazole was compared with liposomal amphotericin B in 837 adolescent and adult subjects.37 No difference in treatment success was observed when using a composite end point; however, fewer breakthrough fungal infections were seen in those who were receiving voriconazole.
Khayat et al38 retrospectively compared liposomal amphotericin B and caspofungin in 26 febrile and neutropenic children. The duration of neutropenia and treatment were significantly shorter in those receiving caspofungin. No difference in effectiveness was observed (92% in both cohorts). Liposomal amphotericin B and caspofungin were compared in 1095 febrile neutropenic adults. Despite there being a greater number of patients who survived for
7 days after completion of the study therapy in the caspofungin group, no overall difference in treatment success was observed.39
In summary, no clear differences in overall treatment success or mortality have been demonstrated in pediatric or adult trials in which empiric conventional amphotericin B and lipid preparations were compared in subjects with prolonged fever and neutropenia. Fewer breakthrough infections may occur in subjects who receive liposomal amphotericin B. In azole-naive neutropenic subjects, conventional amphotericin B and fluconazole seem equally effective. Furthermore, in febrile neutropenic adults, voriconazole and caspofungin seem to be as effective as liposomal amphotericin B.
Antifungal Therapy in Proven Candidemia or Invasive Candidiasis
In pediatric and neonatal case series, Candida albicans and Candida parapsilosis are the most frequently isolated organisms responsible for invasive disease.1,4042 Other species such as Candida tropicalis, Candida glabrata, and Candida krusei occur less frequently than in adult cohorts. C tropicalis, C glabrata, C krusei, and Candida guillermondii frequently have reduced susceptibility to fluconazole, and Candida lusitaniae is thought to have variable sensitivity against amphotericin B.43
Higher rates of candidemia with nonalbicans species are seen in those who receive systemic antifungal agents.6 Previous fluconazole therapy is a risk factor for infection with a fluconazole-resistant organism.6 The association between C parapsilosis and central-line infection has been documented by a number of authors.41,44
Numerous antifungal agents have been used in open-label trials in neonates and children with candidemia/invasive candidiasis. Amphotericin B and its lipid preparations,4552 azoles,5355 and echinocandins56,57 have all been shown to be effective in neonates with candidal infections. Amphotericin B-based preparations, azoles, and echinocandins have also been shown to be effective in predominantly immunosuppressed pediatric populations.55,5866 The most frequently used end point is microbiologic clearance of candidemia (CAB: 68%46; lipid preparations of amphotericin B: 83%100%4548,51,52; fluconazole: 72%97%53,55,61,62; itraconazole: 81%58; caspofungin: 85%100%56,57; micafungin: 72%66). Comparing trials is difficult given the small numbers, mixed patient populations, and varying comorbidities. Furthermore, newer agents are frequently used as salvage therapy in open-label trials after failure of standard agents.
Two small RCTs have compared antifungal agents in pediatric candidemia. Driessen et al67 compared CAB (1 mg/kg per day) with fluconazole (5 mg/kg per day) in 23 predominantly preterm neonates. Although the trial was significantly underpowered, no significant difference in treatment success or mortality rate was demonstrated. Mondal et al68 compared enterally administered fluconazole (10 mg/kg per day) and itraconazole (10 mg/kg per day) in 43 pediatric intensive care patients with candidemia. No significant difference in total mortality rate (18.2% vs 9.5%) or attributable mortality rate (4.8% vs 4.5%) was demonstrated. The time to mycological cure (5.6 ± 1.6 vs 5.5 ± 1.9 days) and clinical cure (7.0 ± 2.6 vs 7.9 ± 1.3 days) was similar for both treatment groups.
The therapeutic equivalence of fluconazole and CAB has been demonstrated in predominantly nonneutropenic adolescents and adults with candidemia or invasive candidiasis.6971 Furthermore, the therapeutic equivalence of voriconazole compared with CAB followed by fluconazole was demonstrated in 370 nonneutropenic adolescents and adults.72 Voriconazole was superior in subjects with C tropicalis sepsis. Therapeutic equivalence of fluconazole and voriconazole was demonstrated for esophageal candidiasis by Ally et al73 in adult patients with cancer and HIV.
Echinocandins have been compared with CAB and azoles in adults with candidemia and invasive candidal infections. No comparative pediatric trials have been performed. Caspofungin and CAB seem equally effective in adult patients with candidemia and oropharyngeal or esophageal candidiasis.7476 No difference in treatment success has been demonstrated in adults with esophageal candidiasis treated with fluconazole and caspofungin, micafungin, or anidulafungin.7779 Caspofungin has been shown to be effective in treating fluconazole-resistant esophageal candidiasis.80
At least 14 days of therapy after the last positive blood-culture result is recommended for children and neonates with candidemia in the absence of disseminated disease.81 Donowitz and Hendley82 retrospectively reviewed short-course therapy in 30 neonatal and pediatric patients with candidemia. Clinical and mycological cure was documented in 58% of subjects administered 7 to 14 days of antifungal therapy after bloodstream sterilization. No comparison has been performed with longer courses of antifungal therapy. An intravascular device is the most frequent source of candidemia in children (D. Marriott, MBBS, T. Sorrell, MD, M. Slavin, MBBS, S. Chen, MBBS, PhD, and D. Ellis, PhD, "The Australian Candidaemia Study: A Prospective Population Based Laboratory Surveillance for Candidaemia in Australia Over a Three Year Period," unpublished work, 2006). Management of intravascular devices is integral in the management of children with candidemia but is beyond the scope of this review (see Nucci and Anaissie83).
Treatment for deep candidal infection frequently requires prolonged therapy. Treatment recommendations are from open-label and observational studies rather than comparative trials. Pappas et al81 recommended at least 4 weeks of therapy in candidal meningitis after resolution of symptoms and signs. Combination therapy (ie, amphotericin B derivative and flucytosine) is often recommended. The role of newer antifungal agents has not yet been fully established. Prolonged antifungal therapy (ie, >6 weeks) is frequently required for chronic disseminated candidiasis, endocarditis, endophthalmitis, and osteomyelitis.81 This prolonged treatment is influenced by the underlying degree of immunosuppression, the presence of prosthetic material, and the response to both medical therapy and surgery where warranted.
In conclusion, no adequately powered comparative trials in pediatric candidemia or invasive candidiasis have been performed. No difference in treatment success has been seen when CAB, azoles, and echinocandins were compared in nonneutropenic adolescents and adults. Previous antifungal therapy may have an impact on the infecting Candida species and should influence empiric therapy.
Antifungal Therapy in Proven or Suspected Invasive Aspergillosis
There is a paucity of comparative data for pediatric aspergillosis. Furthermore, a lack of uniform definitions for diagnosis and treatment response, the relatively small subject numbers in pediatric studies, the lack of pediatric subgroup analysis in larger studies, and differences in the study populations create uncertainty about optimal management.84 Assessment of open-label pediatric trials indicates that the most frequently used end point has been clinical cure and/or improvement. Treatment response rates have varied markedly (CAB: 32%16; ABLC: 39%78%60,63,85; voriconazole: 60%59; caspofungin: 70%65; micafungin: 45%86). Mixed patient populations and the use of antifungal agents as either primary or salvage therapy make interpretation of the data difficult.
The only comparative trial of antifungal therapy in pediatric aspergillosis compared ABCD with CAB. Children and adults who were given ABCD were compared with a historic cohort treated with CAB.87 ABCD was administered to patients who were intolerant of or refractory to CAB therapy, had preexisting renal impairment, or were enrolled in ABCD dose-escalation trials after hematopoietic stem cell transplantation. Pediatric numbers were small, and no pediatric subgroup analysis was performed. White et al87 found that treatment success and survival were greater in the ABCD group. Those treated with ABCD were younger and less likely to be neutropenic.
Using comparative data from adult trials, a number of conclusions can be drawn regarding the relative efficacy of different antifungal agents. CAB was compared with lipid preparations in 2 underpowered RCTs: no significant difference in treatment outcome was observed when CAB (1.01.5 mg/kg per day) was compared with liposomal amphotericin B (5 mg/kg per day) or ABCD (6 mg/kg per day).88,89
Two randomized trials compared different doses of liposomal amphotericin B in proven or probable aspergillosis. No difference in clinical response was observed between 1 and 4 mg/kg per day of liposomal amphotericin B, although the trial was insufficiently powered.90 In patients with proven aspergillosis at group assignment, clinical response was seen in 58% of those who received 4 mg/kg per day compared with 37% who received 1 mg/kg per day. Another trial compared 3 and 10 mg/kg per day of liposomal amphotericin B in 339 subjects with filamentous fungal infection (predominantly aspergillosis). No differences in treatment success at 12 weeks (50% vs 48%, respectively) or survival (72% vs 58%, respectively) were observed.91
Herbrecht et al92 compared CAB (1 mg/kg per day) with voriconazole (6 mg/kg twice daily for 24 hours followed by 4 mg/kg twice daily) in 277 adolescents and adults with proven or probable aspergillosis. Voriconazole was superior with regards to treatment success (53% vs 32%, respectively) and survival (71% vs 58%, respectively). Some of the voriconazole treatment success may be attributable to duration of therapy, because it was significantly longer in the voriconazole group (77 vs 10 days, respectively). Other licensed antifungal agents were used less frequently in those who were administered voriconazole compared with CAB (36% vs 80%, respectively).
Caspofungin and micafungin have been shown to be effective in open-label trials in adults with aspergillosis who were intolerant of or refractory to other antifungal agents.9395 No comparative trials have been published to date.
The duration of antifungal therapy required for invasive aspergillosis in children and adults has not been determined. Herbrecht et al92 clinically and radiologically evaluated subjects after 12 weeks of antifungal therapy. In an open-label study of voriconazole use in children with IFI (predominately aspergillosis), the median duration of therapy was 93 days (range: 1880).59 The length of therapy administered needs to influenced by response to therapy and immunologic recovery.
In summary, pediatric data are insufficient to guide therapy in children with invasive aspergillosis. Adult data suggest that in subjects with invasive aspergillosis, voriconazole is superior to conventional amphotericin B and associated with superior survival. Higher doses of liposomal amphotericin B are not superior to 3 mg/kg per day of liposomal amphotericin B. Echinocandins are effective in aspergillosis, although no comparative trials have been completed.
Combination Antifungal Therapy
Given the high morbidity of IFI, the role of combination therapy is frequently considered. To date, no pediatric combination trials have been published, although research is underway. In nonneutropenic adults with candidemia, amphotericin B and fluconazole were compared with amphotericin B alone.96 Clearance of Candida from the bloodstream occurred more frequently with combination therapy; however, no difference in the primary end point or 90-day mortality rate was demonstrated. Combination therapy with voriconazole and caspofungin (n = 16) was retrospectively compared with voriconazole (n = 31) in a population of adults with proven or probable aspergillosis and progression despite treatment with amphotericin B.97 Three-month survival, estimated with Kaplan-Meier curves, demonstrated a reduced mortality rate with combination therapy (hazard ratio: 0.28; P = .011).
In summary, there is insufficient evidence currently to support the routine use of combination therapy in children with candidemia, invasive candidiasis, or aspergillosis. Combination therapy should be reserved for salvage therapy pending additional trial data. Two antifungal agents from different classes should be used for salvage therapy.
Pediatric Antifungal Pharmacokinetics and Drug Interactions
Significant differences between adult and pediatric antifungal pharmacokinetics have been demonstrated with a number of antifungal agents. Pediatric amphotericin B pharmacokinetics differ significantly from adults.59,98100 Because amphotericin B products do not accumulate in plasma, have large volumes of distribution, and long elimination half-lives, recommended doses are not dissimilar from adult recommendations. Pediatric studies reveal more rapid elimination and larger volumes of distribution in children administered fluconazole compared with adults.101103 From pharmacokinetic modeling, 12 mg/kg per day of fluconazole is required to achieve comparable plasma concentrations to adults receiving 400 mg/day.101 Neonatal fluconazole elimination is reduced, necessitating less frequent dosing. Voriconazole pharmacokinetics in children are linear compared with the nonlinear pharmacokinetics seen in adults. The area under the curve in children given 4 mg/kg 12-hourly is similar to adults given 3 mg/kg 12-hourly.104 Doses of up to 11 mg/kg twice daily may be required in children to achieve concentrations similar to 4 mg/kg twice daily in adults. Again, pediatric caspofungin pharmacokinetics are different to adults administered the drug. Variations in the pharmacokinetic results with both weight and age suggest that weight-based dosing fails to provide consistent pharmacokinetics across all ages. In children and adolescents, 50 mg/m2 best approximates the area under the curve and trough concentration of adults receiving 50 mg/day.105 In premature neonates, 2 mg/kg or 25 mg/m2 best approximate adult pharmacokinetic data.106
Adult and pediatric pharmacokinetics seem to be similar for itraconazole,107109 posaconazole,110 micafungin,111,112 and anidulafungin.113 Additional studies are required to define the correct pediatric dosage for newer antifungal agents including posaconazole, ravuconazole, micafungin, and anidulafungin.110113 Currently recommended pediatric dose ranges are listed in Table 3.
Competition for cytochrome p450 metabolism is a problem with certain antifungal agents. This is of particular relevance to the interaction of azoles with cyclophosphamide and other immunosuppressants (cyclosporine, tacrolimus, and sirolimus). Dose reduction (cyclosporine or tacrolimus with itraconazole or voriconazole) or avoidance (sirolimus with voriconazole) is recommended.21,114120 Despite initial concerns about cyclosporine and caspofungin coadministration, a number of observational studies in children and adult subjects who received concomitant therapy have demonstrated the safety of this combination.65,121,122
Antifungal Toxicity in Children
The development of new antifungal agents has been driven by the toxicities that occur with CAB. Azoles, lipid preparations, and echinocandins are all associated with significantly less toxicity. The toxicity of CAB,46,123132 lipid preparations,45,4751,60,63,85,133,134 fluconazole,54,55,61,62,67,68,102,128,135138 itraconazole,68,108,109 voriconazole,59,104,139,140 caspofungin,56,57,65,105,141 micafungin,94,111 and anidulafungin113 have been determined in a number of pediatric trials, yet there is a paucity of comparative data. Furthermore, a lack of uniform definitions hinders comparison.
Two pediatric randomized trials that compared CAB to ABCD demonstrated a reduced rate of nephrotoxicity with ABCD (52% vs 12% in both studies; P < .01).27,29 Although Prentice et al26 failed to detect a significant difference in the rates of nephrotoxicity when they compared 1 mg/kg per day of CAB and 1 to 3 mg/kg per day of liposomal amphotericin B (21% vs 8%11%, respectively; P = .10), their definition of nephrotoxicity was less stringent (see Table 2).
These pediatric data are supported by numerous larger trials. Three meta-analyses demonstrated a 49% to 75% reduction in nephrotoxicity with lipid preparations compared with CAB.30,142,143 If nephrotoxicity secondary to a lipid preparation occurs, it occurs after a longer course of therapy.26,29 Both adult and neonatal studies have demonstrated that lipid preparations are safe in subjects with pretreatment nephrotoxicity.46,144,145 No pediatric studies have compared different lipid preparations. In contrast to the findings of Wingard et al,31 a recent meta-analysis demonstrated no significant difference in rates of nephrotoxicity seen with liposomal amphotericin B and ABLC.143
Both azoles and echinocandins cause less nephrotoxicity than CAB and liposomal amphotericin B when compared in adolescents and adults.34,36,37,71,72,92 No trials comparing ABLC or ABCD to azoles and echinocandins exist to date. In children who were given fluconazole and itraconazole, similar rates of nephrotoxicity have been seen.68 When compared with both CAB and liposomal amphotericin B, less nephrotoxicity is seen in adults who are given caspofungin.39,74,76 No difference in the rates of nephrotoxicity have been seen when caspofungin and fluconazole were compared in adults.77
A number of authors have identified specific risk factors for amphotericin Binduced nephrotoxicity. Amphotericin B dose, preexisting renal impairment, hyponatremia, hypovolemia, and the concurrent use of nephrotoxic medications are associated with an increased risk of amphotericin B nephrotoxicity.28,129,146151 Age and underlying disease are not associated with increased risk. When nephrotoxic medications are assessed independently, cyclosporine and diuretics increase the rate of nephrotoxicity, whereas aminoglycosides and vancomycin in isolation seem not to increase the risk.147149In a study by Walsh et al,28 the risk of nephrotoxicity more than doubled when
2 concurrent nephrotoxins (cyclosporine, aminoglycosides, or foscarnet) were used. Avoidance of nephrotoxins and hypovolemia as well as sodium loading before amphotericin B use may decrease the risk of nephrotoxicity. Wingard et al146 determined that hematopoietic stem cell recipients were >5 times more likely to require hemodialysis when administered amphotericin B for aspergillosis than solid organ transplant- and nontransplant-related chemotherapy recipients. Dialysis was a significant risk factor for death.
Infusional toxicity (most frequently chills, rigors, fever, nausea, and vomiting) is a frequent complication of amphotericin B treatment in children and adults. Despite premedication and the development of tolerance, infusional toxicities continue to pose a problem.152,153 Infusional toxicities are rarely reported in neonates.46,127 Comparative trials with adult and pediatric patients have demonstrated that liposomal amphotericin B is the amphotericin B product associated with the least infusional reactions.143 CAB, ABLC, and ABCD have similar rates of infusional reactions.143
Newer agents have been compared with both conventional and lipid preparations of amphotericin B. Compared with amphotericin B products, fluconazole, itraconazole, voriconazole, and caspofungin are responsible for less infusional reactions.34,36,74,92 Furthermore, both voriconazole and caspofungin are associated with less infusional toxicity than liposomal amphotericin B.37,39 No difference in infusional toxicity has been seen when fluconazole and micafungin were compared.78
Continuous amphotericin B infusions result in less nephrotoxicity and infusional toxicity compared with intermittent infusion.154,155 No adult or pediatric trials have compared continuous CAB infusions with lipid preparations. Experimental in vitro and in vivo studies support concentration-dependant killing with a prolonged postantibiotic effect, which suggests that a large daily dose will be most effective and that achieving an optimal peak concentration is important.20 The limitations of vascular access in children with multiple comorbidities and therapies pose significant problems with continuous infusions.
Hepatotoxicity has been assessed in a number of pediatric and adult trials. No significant difference between CAB and any lipid preparation of amphotericin B has been demonstrated.26,28,156 No significant difference has been detected between azoles and conventional or liposomal amphotericin B.33,34,37,67,68,71,92 Furthermore, no significant difference has been observed between caspofungin, CAB, and fluconazole.74,76,77
Rash is seen more frequently in adults who are given fluconazole or voriconazole compared with amphotericin B.34,92 Visual disturbance or eye symptoms are reported more frequently in both adults and children taking voriconazole.37,92
In conclusion, pediatric and adult toxicity data demonstrate clear differences when comparing different agents. Lipid preparations of amphotericin B cause less nephrotoxicity than CAB, yet azoles and echinocandins are less nephrotoxic than all amphotericin B preparations. Preexisting renal impairment, concurrent nephrotoxins, or those receiving large cumulative doses have a higher risk of nephrotoxicity. Hematopoietic stem cell recipients are at the greatest risk of needing dialysis. Rates of infusional toxicity also vary widely: liposomal amphotericin B is associated with less infusional toxicity compared with CAB, yet both azoles and echinocandins seem to result in lower rates than all amphotericin B preparations. Rash, visual disturbances (with voriconazole), and drug interactions with azoles create additional complexity when administering antifungal therapy.
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No consistent differences in treatment success or mortality rate have been demonstrated in comparative trials in patients with fever with neutropenia, candidemia, and invasive candidiasis. Initial therapy with voriconazole is superior to conventional amphotericin B in aspergillosis, with an associated survival advantage. Numerous differences in antifungal toxicity have been observed in children and adults when conventional amphotericin B is compared with newer antifungal agents. Insufficient evidence is available to recommend routine use of combination therapy for candidemia or aspergillosis.
Additional research on antifungal agents in children to assess pharmacokinetics and toxicity of newer agents, relative efficacy, and cost is needed. Given the difficulties in performing adequately powered efficacy trials in children, in whom the incidence of IFIs is low, the ongoing extrapolation of adult data to pediatric practice is likely to be required.
| ACKNOWLEDGMENTS |
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| FOOTNOTES |
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Address correspondence to Pamela Palasanthiran, MBBS, FRACP, MD, Department of Immunology and Infectious Diseases, Sydney Children's Hospital, High Street, Randwick, New South Wales 2130, Australia. E-mail: pamela.palasanthiran{at}sesiahs.health.nsw.gov.au
The authors have indicated they have no financial relationships relevant to this article to disclose.
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