Home

review article

Indian Pediatr 2009;46: 225-231

New Antifungal Agents in Pediatric Practice

S Das, *M R Shivaprakash and *A Chakrabarti

From the Division of International Medicine and Infectious Diseases, Weil Medical College of Cornell University,
New York, NY, USA; and *Department of Medical Microbiology, Postgraduate Institute of Medical Education and Researc

h, Chandigarh, India.

Correspondence to: Dr Arunaloke Chakrabarti, Professor, Department of Medical Microbiology, PGIMER, Chandigarh 160 012, India.
E-mail: [email protected]

Abstract

Clinical needs for new antifungal agents have steadily increased with the rise and alteration in spectrum of invasive mycoses in children and neonates having AIDS, malignancies and undergoing immunosuppressive therapies. Several new options are now available for management of serious fungal infections. The aim of this review is to summarize the key features of the new antifungal agents and novel targets being investigated for the treatment of fungal infections, with special reference to its use in the treatment of pediatric fungal infections. New triazoles have broad spectrum of activity with voriconazole presently being the drug of choice against invasive aspergillosis, and posaconazole is the possible first substitute of amphotericin B against zygomycosis. Echinocandins with new mode of action of inhibition of fungal cell wall polysaccharide synthesis are effective in treating candidemia and invasive candidiasis. Some of these agents are however, still awaiting FDA approval for their use in pediatric practice.

Keywords: Antifungal, Antimicrobial, Mycoses, Treatment.

Invasive fungal infections (IFI) in the immunocompromised children with hematological malignancies and hematopoetic stem cell transplant (HSCT) recipients and the neonates, especially the very low birth weight infants (VLBW) and the extremely low birth weight (ELBW) infants is associated with significant morbidity, mortality and high health care costs(1-5).

While Candida and Aspergillus species are the most common causes of opportunistic fungal infections in India(6,7), previously uncommon, emerging fungal species such as Fusarium, Pichia and Scedosporium spp. are also being increasingly reported worldwide(8-10). This emergence of lesser-known fungal pathogens coupled with the increased antifungal drug resistance in commonly encountered fungal pathogens, has prompted a considerable expansion in the choice of antifungal drugs. Currently 4 classes of drugs are available for treating IFIs: polyenes, triazoles, echinocandins and nucleoside analogues. Among these, the echinocandins are an entirely new class of drugs and the triazoles have undergone significant development with a new and improved generation of azoles being added to the list (posaconazole, ravuconazole and voriconazole), while several others are being developed (isavuconazole, albaconazole). Many of these new drugs have already been licensed in many countries around the world including India, and are being used for the treatment of pediatric IFI. However, pediatric dosage finding and safety evaluations of several of these compounds are incomplete and data show that significant differences in pharmacokinetic properties exist between pediatric and adult patients. The purpose of this review is to describe the new antifungal agents with special reference to the status of their clinical development and use in pediatric patients. The new antifungal agents and their use are detailed in Tables I and II.

TABLE I

Characteristics of New Antifungal Agents

Drug	Antifungal activity					Route
	Candida spp.	Cryptococcus spp.	Aspergillus spp.	Other hyalohypho- mycetes	Zygomycetes
Voriconazole	+	+	+	+/–	–	iv/po
Posaconazole	+	+	+	+/–	+/–	po
Ravuconazole	+	+	+	+/–	+/–	iv/po
Caspofungin	+	-	+	–	–	iv
Anidulafungin	+	-	+	–	–	iv
Micafungin	+	-	+	–	–	iv

TABLE II



Treatment Options for Invasive Fungal Infections

Clinical Condition	Underlying disease/	Drug of choice	Adverse effects	Alternate drug
	condition
Prophylaxis for IFI^a	Neutropenic patient	Posaconazole	GI intolerance,	Itraconazole/
	with malignancy/HSCT		CYP450 drug	fluconazole
			interactions
Empiric therapy for IFI	Neutropenic patient with	Caspofungin	Fever, rash,	LAmB
	malignancy/HSCT and		headache
	clinical and/or radiological		hematological
	signs of IFI without any		abnormalities,
	laboratory evidence;		hepatotoxicity,
	Possible IA^b		GI abnormalities
Preemptive/targeted	Neutropenic patient with	iv	hepatotoxicity,	iv LAmB
therapy for IFI	malignancy/HSCT and clinical	Voriconazole	cheilitis, photophobia,
	signs of IFI with laboratory		blurry vision, CYP450
	evidence of fungal infection;		drug interactions
	Probable or proven IA^c
Prophylactic therapy	Neutropenic	Fluconazole^e
for candidiasis in the	patients
ICU^d
Empiric/targeted	Neutropenic/	Caspofungin	Fever, rash, headache	LAmB
treatment for invasive	HSCT		hematological abnor-
candidiasis			malities, hepatotoxicity,
			GI abnormalities
	Non-neutropenic/	Echinocandin^f	Fever, rash, headache	LAmB
	ICU patients	(should be	hematological abnor-
		changed to	malities, hepatotoxicity,
		fluconazole	GI abnormalities, thrombo-
		once sensitivity	phlebitis, epistaxis,
		data is obtained)	mucositis
IFI = Invasive fungal infection, HSCT=Hematopoetic stem cell transplant, GI= gastrointestinal, CYP 450= cytochrome P 450, IA=invasive aspergillosis, LAmB=Liposomal Amphotericin B, iv = intravenous, ICU=Intensive care unit, ^aSome of the therapeutic options are based on trials or FDA recommendations in adults, as sufficient pediatric data is unavailable. Please see text for details.^b,cGuidelines for diagnosis according to 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) Consensus Group (38).^dProphylactic use of antifungals in ICU is recommended based on hospital epidemiology and is justified if incidence of invasive candidiasis in ICU reaches 10% in spite of active prevention (39).^eMay select for fluconazole resistant non-albicans species.^fCaspofungin is preferred in pediatric population (40).

New Azoles

Azoles exert their antifungal activity by binding to the ergosterol biosynthetic enzyme, lanosterol 14-a demethylase and inhibiting ergosterol synthesis. Earlier members of this group had a rather narrow spectrum of activity against some but not all yeasts, with itraconazole demonstrating some activity against molds. New generation triazoles have an expanded spectrum of action with cidal activity against a broad spectrum of molds and enhanced activity against Candida spp. and other yeasts. The new azoles that have been developed include voriconazole, posaconazole and ravuconazole; and isavuconazole and albaconazole are under study. While all azole derivatives share the common mechanism of action, each possesses a unique affinity for the various fungal cytochrome P450 enzymes and thus a unique spectrum of activity and safety profile. However, the common mechanism of action leads to cross-resistance among azoles.

Voriconazole. It has been developed from fluconazole by adding a a-methyl group and substituting a fluoropyrimidine ring for one of the azole groups. This achieved fungicidal activity against Aspergillus and other molds but not against Zygomycetes(11). United States Food and Drug Administration (FDA) approved it for the treatment of primary acute invasive aspergillosis and serious infections caused by Scedosporium spp. and Fusarium spp in 2002, and in 2005 approved its use for the treatment of candidemia in adult patients without neutropenia. It can be used as both oral and intravenous formulations and is currently available in India.

Given orally on an empty stomach, the drug is rapidly and almost completely absorbed but food lowers the drug’s bioavailability and delays absorption. The pharmacokinetics of voriconazole in children appears linear in contrast to non-linear pharmacokinetics in adults. This was based on single dose, open-label, two-center study involving children ages 2-11 years (mean 5.9 years); and a multi-dose, open, multicentric study in two age cohorts (age2-6, and 6-12 years with mean age 6.4 years). These studies showed that a pediatric dose of approximately 11mg/kg administered every 12h are approximately bioequivalent to an adult dosage of 4mg/kg given every 12h(12). Other variables such as CYP2C19 genotype, body weight, kidney and liver functions also affect plasma concentrations of the drug achieved after a given dosage. Selection of a fixed dose therefore yields a wide variety of plasma concentrations and there is a need of therapeutic drug monitoring for patients being treated with voriconazole(13,14). Though, voriconazole has not received FDA approval for use in children 2-11 years of age, it is approved in the European Union on the basis of compassionate use data(15). Voriconazole has not yet been formally tested in neonates due to the visual adverse events reported in adults and children. There is a major concern over its effect on the developing retina(16). Recently a case series of safe voriconazole use in critically ill newborn with cardiac disease has been reported from India(17). No significant drug interaction despite use of several cardiac drugs or any side effect was observed.

The largest clinical study of voriconazole in the pediatric population was an open-label com-passionate-use evaluation of voriconazole in 58 children with proven or probable invasive fungal infection; refractory to or intolerant of conventional antifungal therapy. Voriconazole was administered as a loading dose of 6mg/kg every 12h on the first day of therapy, followed by 4mg/kg every 12 h on subsequent days. When possible, the conversion to oral therapy was made with a dose of 100mg or 200mg twice a day for patients weighing <40kg or ³40kg respectively. After a 93-day median duration of therapy, complete or partial response was observed in 43% of children with aspergillosis, 50% with candidemia, and 63% with scedosporiosis. Treatment related adverse effect occurred in over 5% of patients, and were transaminase or bilirubin elevation in 13.8% of patients, rash in 13.8%, abnormal vision and photosensitivity reaction in 5% patients each; while 5% patients discontinued therapy due to intolerance(15).

Posaconazole. An oral 2nd generation azole, was approved by the FDA in 2006 for the prophylaxis of invasive Aspergillus and Candida infections in patients at increased risk for these infections due to hematopoietic stem cell transplant, graft versus host disease, and hematological malignancies with prolonged neutropenia from chemotherapy. This drug is not yet commercially available in India. Posaconazole is similar in structure to itraconazole and has a broad-spectrum of activity in vitro against a wide array of yeasts, moulds, and especially the Zygomycetes, for which treatment options are limited. Unlike voriconazole, absorption is better when administered with fatty meals with extensive distribution in the tissues. It is only used as a compassionate release agent in oral formulation. It is active in vivo in several experimental models of pulmonary, cerebral, and disseminated asper-gillosis(18,19). Randomized comparative studies of efficacy and safety of posaconazole in HIV-infected adults with oropharyngeal candidiasis indicate that it is as effective as fluconazole and well tolerated. A 40-80% response rate has been shown in patients with a wide variety of IFIs including cryptococcosis, candidiasis, phaeohyphomycosis, aspergillosis and fusariosis(15,20,21). Limited efficacy data are available in children. Posaconazole plasma levels were compared between juvenile (aged 8-17 years) and adult (aged 18-64 years) patients participating in an open-label phase III study. Posaconazole, 800 mg/day was given as salvage therapy for proven or probable IFI, refractory to standard antifungal therapy. Posaconazole concentrations in plasma were similar for juvenile and adult patients, suggesting that clinical outcomes are expected to be similar in adults and juvenile group with refractory invasive fungal infection(22). There is no data available on the safety and efficacy of posaconazole in neonates.

Ravuconazole. It is a derivative of fluconazole with potent activity against Candida spp., Aspergillus spp., C. neoformans, H. capsulatum and C. immitis in vitro. It is fungicidal, has 47-74% bioavailability with linear pharmacokinetics, and possesses long half-life of approximately 100h. Activity of ravuconazole against Fusarium and Scedosporium is less than that of voriconazole and cross-resistance between fluconazole and ravuconazole has been observed with Candida glabrata and other Candida spp(23). The drug has no activity against Rhizopus or Mucor spp. The safety and tolerability of ravuconazole has been tested in a handful of adult patients and was found to be similar to that of fluconazole. Unfortunately, no pediatric data is available.

BAL-8557. It is the water-soluble pro-drug that gets cleaved to BAL-4815 (isavuconazole). This new azole has very high (98%) plasma protein binding in humans and has potent in vitro activity against Aspergillus spp. including A. fumigatus, A. flavus, A. terreus and A. niger. It has lower MIC and MIC50 values than those of voriconazole for the majority of Candida spp. tested, including C. glabrata and C. krusei, and exhibits activity against dermatophytes and Zygomycetes(24, 25, 26). Several randomized clinical trials are evaluating the safety and efficacy of this drug for the treatment of invasive Candida infections (23).

Additional triazoles such as albaconazole are undergoing early clinical evaluation and their future is uncertain. For all new triazoles, concerns about emerging drug-resistant fungi and the problem of management of breakthrough infections will dictate their role in future antifungal prophylaxis and treatment.

B. Echinocandins

This is an entirely new class of antifungal agents that exert their activity by noncompetitive inhibition of 1, 3-b-D-glucan, an essential fungal cell wall polysaccharide. Structurally, they are characterized by a cyclic hexapeptide core linked to a lipid side chain that is variably configured. Echinocandins are fungistatic (due to blockade of cell wall synthesis) against Aspergillus and fungicidal (due to loss of cell wall integrity) against Candida activities. The unique mechanism of action has dual benefit: fewer side effects as cell walls are lacking in human cell, and possibility of successful combination with agents acting on cell membrane as combination therapy. All drugs in this group have poor bioavailability and have to be administered intravenously.

Caspofungin. The drug was previously approved for use in adults for empiric therapy of presumed fungal infections in febrile neutropenic patients, for the treatment of candidemia and esophageal candidiasis, and for treatment of refractory invasive aspergillosis. As of July 2008, caspofungin has received FDA approval for pediatric use. The details of pharmacokinetics, dosing and clinical efficacy has been published earlier in Indian Pediatrics(27).

Even though dosage and pharmacokinetics of caspofungin in neonates remain unclear and no clinical trial data is available, there are several reports of use of caspofungin in neonates with invasive Candida infection. It appears from these reports that caspofungin could be considered an alternative therapy for neonatal candidiasis refractory to conventional antifungal therapy(28).

Micafungin and Anidulafungin. These drugs are other echinocandins with spectra of activity similar to caspofungin. Both drugs are undergoing clinical trials and are still not available in India. These new echinocandins achieve highest concentration in lung, followed by the liver, spleen, and kidney. Micafungin reaches brain at undetectable or low level, but anidulafungin reaches in measurable concentration. Micafungin has been approved by FDA in 2005 for therapy of esophageal candidiasis and for prophylaxis of Candida infection in hematopoietic stem cell transplant recipients. FDA approved Anidulafungin in 2006 for therapy of candidemia and esophageal candidiasis.

In recent years, several pediatric studies have been completed using micafungin. A phase I single-dose, multi-center, open-labeled neonatal study evaluated three dosages (0.75mg/kg/day, 1.5mg/kg/day, and 3mg/kg/day) in two infant groups (weighing 500-1000g, and >1000g). The mean serum concentration of micafungin was lower in smaller infants and serum half-life was shorter and clearance was more rapid (29). A similar phase I pediatric (2-12 years old) febrile neutropenia study found that doses up to 4mg/kg/day were well tolerated without any side effect(30). In general, the terminal half-life of micafungin does not change appreciably in pediatric versus adult patients, and the volume distribution is only slightly higher in children(31). Micafungin in combination with second antifungal agent in pediatric and adult bone marrow transplant recipients with invasive aspergillosis revealed an overall complete or partial response of 39.1% of adult patients and 37.5% of pediatric patients(32). In an open-label non-competitive study of new or refractory candidemia including 15.1% pediatric patients, the overall complete or partial response was 85.1% in adult patients and 72.2% in pediatric patients(33). There is no accepted dosage schedule of micafungin in pediatric patients available yet.

The pharmacokinetics of anidulafungin showed approximately six-fold lower mean peak concen-tration in plasma, and two-fold lower AUC values compared with values for similar doses of caspofungin and micafungin. Results of a multicenter, ascending-dosage study of trial of anidulafungin in neutropenic pediatric patients have recently been published. Patients were divided into two age cohorts (2 to 11 years and 12 to 17 years) and were enrolled into sequential groups to receive 0.75 or 1.5 mg/kg of body weight/day. The drug was well tolerated in pediatric patients with only mild to moderate adverse effects. It was found that the drug can be dosed based on body weight and pediatric patients receiving 0.75mg/kg/day or 1.5mg/kg/day were found to have pharmacokinetics similar to adult patients receiving 50 or 100mg/day respectively (34). This is in contrast to caspofungin, which requires a dosage adjustment based upon a calculation of body surface area rather than a weight-adjusted scale.

Aminocandin (HMR3270). This is a semi-synthetic fermentation product from Aspergillus sydowi, and is similar in structure to the other members of the echinocandin class. It has demonstrated potent activity against both Candida and Aspergillus spp. (including itraconazole resistant strains). MIC results for molds are however species specific being very low for Aspergillus fumigatus (MIC90 0.5 mg/L) but not active against Scedosporium spp., Fusarium spp. and the Zygomycetes(35).

Conclusion

The advances in antifungal therapy have been impressive in the last few years and new therapeutic strategies have had significant impact on the mortality of IFI (36). This has great implications in the field of pediatric antifungal therapy, especially since the number of children receiving chemotherapy and HSCT continue to increase. However there is need for more clinical trials to study the use of these new agents and their efficacy in different clinical conditions, specifically in the pediatric age group.

Contributors: AC formulated the idea of writing this review, SD prepared the initial manuscript, MRS collected the references. All three authors contributed in preparing the final manuscript.

Funding: None.

Competing interests: None stated

References

1. Blyth CC, Palasanthiran P, O’Brien T. Antifungal therapy in children with invasive fungal infections: A systematic review. Pediatrics 2007; 119: 772-784.

2. Pappas PG, Rex JH, Lee J, Hamill RJ, Larsen RA, Powderly W, et al. A prospective observational study of candidemia: epidemiology, therapy and influences on mortality in hospitalized adult and pediatric patients. Clin Infect Dis 2003; 37: 634-643.

3. Lin SJ, Schranz J, Teutsch SM. Aspergillosis case-fatality rate: systematic review of literature. Clin Infect Dis 2001; 32: 358-366.

4. Frattarelli DA, Reed MD, Giacoia GP, Aranda JV. Antifungals in systemic neonatal candidiasis. Drugs 2004; 64: 949-968.

5. O’Grady MJ, Dempsey EM. Antifungal pro-phylaxis for the prevention of neonatal candidiasis? Acta Pediatrica 2008; 97: 430-433.

6. Roy A, Maiti PK, Adhya S, Bhattacharya A, Chakraborty G, Ghosh E, et al. Neonatal candidemia. Indian J Pediatr 1993; 60: 789-801.

7. Vaideeswar P, Sivaraman A, Deshpande JR. Neonatal candidal endocarditis - a rare manifestation of systemic candidiasis. Indian J Pathol Microbiol 1999; 43: 165-168.

8. Chakrabarti A, Singh K, Narang A, Singhi S, Batra R, Rao KL, et al. Outbreak of Pichia anomala infection in the pediatric service of a tertiary-care center in Northern India. J Clin Microbiol 2001; 39: 1702-1706.

9. Richardson M, Lass Flörl C. Changing epidemiology of systemic fungal infections. Clin Microbiol Infect 2008; 14 (Suppl 4): 5-24.

10. Groll AH, Walsh TJ. Uncommon opportunistic fungi: new nosocomial threats. Clin Microbiol Infect 2001; 7 (Suppl 2): 8-24.

11. Almirante B, Rodriguez D. Antifungal agents in neonates. Issues and recommendations. Pediatr Drugs 2007; 9: 311-321.

12. Walsh TJ, Karlsson MD, Driscoll T, Arguedas AG, Adamson P, Saez-Llorens X, et al. Pharmacokinetics and safety of intravenous voriconazole in children after single or multiple-dose administration. Antimicrob Agent Chemother 2004; 48: 2166-2172.

13. Pasqualotto AC, Shah M, Wynn R, Denning DW. Voriconazole plasma monitoring. Arch Dis Child 2008; 93: 578-581.

14. Pascual A, Calandra T, Bolay S, Buclin T, Bille J, Marchetti O. Voriconazole therapeutic drug monitoring in patients with invasive mycoses improves efficacy and safety outcomes. Clin Infect Dis 2008; 46: 201-211.

15. Walsh TJ, Lutsar I, Driscoll T, Dupont B, Roden M, Ghahramani P, et al. Voriconazole in the treatment of aspergillosis, scedosporiosis and other invasive fungal infections in children. Pediatr Infect Dis J 2002; 21: 240-248.

16. Steinbach WJ, Walsh TJ. Mycoses in pediatric patients. Infect Dis Clin North Am 2005; 19: 603-615.

17. Kohli V, Taneja V, Sachdev P, Jorhi R. Voriconazole in newborns. Indian Pediatr 2008; 45: 236-238.

18. Imai JK, Singh G, Clemons KV, Stevens DA. Efficacy of posaconazole in a murine model of central nervous system aspergillosis. Antimicrob Agents Chemother 2004; 48: 4063-4066.

19. Kirkpatrick WR, McAtee RK, Fothergill AW, Loebenberg D, Rinaldi MG, Patterson TF. Efficacy of SCH56592 in a rabbit model of invasive aspergillosis. Antimicrob Agents Chemother 2000; 44: 780-782.

20. Greenberg RN, Mullane K, van Burik JA, Raad I, Abzug MJ, Anstead G, et al. Posaconazole as salvage therapy for zygomycosis. Antimicrob Agents Chemother 2006; 50: 126-133.

21. Raad, II, Hachem RY, Herbrecht R, Graybill JR, Hare R, Corcoran G, et al. Posaconazole as salvage treatment for invasive fusariosis in patients with underlying hematologic malignancy and other conditions. Clin Infect Dis 2006; 42: 1398-1403.

22. Krishna G, Sansone-Parsons A, Martinho M, Kantesaria B, Pedicone L. Posaconazole plasma concentrations in juvenile patients with invasive fungal infection. Antimicrob Agent Chemother 2007; 51: 812-818.

23. Pfaller MA, Messer SA, Boyken L, Rice C, Tendolkar S, Hollis RJ, et al. Cross-resistance between fluconazole and ravuconazole and the use of fluconazole as a surrogate marker to predict susceptibility and resistance to ravuconazole among 12,796 clinical isolates of Candida spp. J Clin Microbiol 2004; 42: 3137–3141.

24. Steinbach WJ, Benjamin DK. New antifungal agents under development in children and neonates. Curr Opin Infect Dis 2005; 18: 484-489.

25. Schmitt-Hoffmann A, Roos B, Heep M, Schleimer M, Weidekman E, Brown T, et al. Single ascending-dose pharmacokinetics and safety of the novel broad-spectrum antifungal triazole BAL4815 after intravenous infusions (50, 100 and 200 milligrams) and oral administrations (100, 200 and 400 milligrams) of its prodrug BAL8557, in healthy volunteers. Antimicrob Agent Chemother 2006; 50: 279-285.

26. Mouton JW, Verweij PE, Warn P, Denning D, Heep M, Isham N, et. al. In vitro activity of a new triazole BAL4815 against Candida isolates with decreased fluconazole susceptibility. Mycoses 2005; 48: 58-59.

27. Parekh A, Dubey AP, Samanta D. Caspofungin. Indian Pediatr 2008; 45: 905-910.

28. Heresi GP, Gerstmann DR, Blumer JL, van den Anchor J, Kearns GL, Reed MD, et al. Pharmacokinetic study of micafungin in premature neonates [abstract]. In: Pediatric Academic Societies Meeting; 3-6 May 2003; Seattle. The Woodlands: Pediatric Academic Societies; 2003. Abstract 83.

29. Seibel NL, Schwartz C, Arrieta A, Flynn P, Shad A, Albano E, et al. Safety, tolerability, and pharmacokinetics of micafungin (FK463) in febrile neutropenic pediatric patients. Antimicrob Agent Chemother 2005; 49: 3317-3324.

30. Townsend R, Bekersky I, Buell DN, Buell NS. Pharmacokinetic evaluation of echinocandin FK463 in pediatric and adult patients [abstract]. In: Focus on Fungal Infections 11; 14-17 March 2001; Washington, DC. Alpharetta: Imedex; 2001. Abstract 024.

31. Kontoyannis DP, Ratanatharathorn V, Young JA, Raymond J, Laverdiere M, Denning DW, et al.. Micafungin alone or in combination with other systemic antifungal therapies in hematopoietic stem cell transplant recipients with invasive aspergillosis. Transplant Infect Dis 2008 Oct 8 [Epub].

32. Ostrosky-Zeichner L, Kontoyannis D, Raffalli J, Mullane KM, Vasquez J, Anaissie, et al. International, open-label, noncomparative, clinical trial of micafungin alone and in combination for treatment of newly diagnosed and refractory candidemia. Eur J Clin Microbiol Infect Dis 2005 ; 24: 654-661.

33. Benjamin DKJ, Driscoll T, Seibel NL, Gonzalez CE, Roden MM, Kilaru R, et al. Safety and pharmacokinetics of intravenous Anidulafungin in children with neutropenia at high risk for invasive fungal infections. Antimicrob Agent Chemother 2006; 50: 632-638.

34. Isham N, Ghannoum MA. Determination of MICs of aminocandin for Candida spp. and filamentous fungi. J Clin Microbiol 2006; 44: 4342-4344.

35. Krcmery V, Kalavsky E. Antifungal discovery, six new molecules patented after 10 years of feast: why do we need new patented drugs apart from new strategies? Recent Patents Anti-Infect Drug Disc 2007; 2 : 182-187.