201
|
Petraitiene R, Petraitis V, Groll AH, Sein T, Schaufele RL, Francesconi A, Bacher J, Avila NA, Walsh TJ. Antifungal efficacy of caspofungin (MK-0991) in experimental pulmonary aspergillosis in persistently neutropenic rabbits: pharmacokinetics, drug disposition, and relationship to galactomannan antigenemia. Antimicrob Agents Chemother 2002; 46:12-23. [PMID: 11751105 PMCID: PMC127008 DOI: 10.1128/aac.46.1.12-23.2002] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antifungal efficacy, pharmacokinetics, and safety of caspofungin (CAS) were investigated in the treatment and prophylaxis of invasive pulmonary aspergillosis due to Aspergillus fumigatus in persistently neutropenic rabbits. Antifungal therapy consisted of 1, 3, or 6 mg of CAS/kg of body weight/day (CAS1, CAS3, and CAS6, respectively) or 1 mg of deoxycholate amphotericin B (AMB)/kg/day intravenously for 12 days starting 24 h after endotracheal inoculation. Prophylaxis (CAS1) was initiated 4 days before endotracheal inoculation. Rabbits treated with CAS had significant improvement in survival and reduction in organism-mediated pulmonary injury (OMPI) measured by pulmonary infarct score and total lung weight (P < 0.01). However, animals treated with CAS demonstrated a paradoxical trend toward increased residual fungal burden (log CFU per gram) and increased serum galactomannan antigen index (GMI) despite improved survival. Rabbits receiving prophylactic CAS1 also showed significant improvement in survival and reduction in OMPI (P < 0.01), but there was no effect on residual fungal burden. In vitro tetrazolium salt hyphal damage assays and histologic studies demonstrated that CAS had concentration- and dose-dependent effects on hyphal structural integrity. In parallel with a decline in GMI, AMB significantly reduced the pulmonary tissue burden of A. fumigatus (P < or = 0.01). The CAS1, CAS3, and CAS6 dose regimens demonstrated dose-proportional exposure and maintained drug levels in plasma above the MIC for the entire 24-h dosing interval at doses that were > or =3 mg/kg/day. As serial galactomannan antigen levels may be used for therapeutic monitoring, one should be aware that profoundly neutropenic patients receiving echinocandins for aspergillosis might have persistent galactomannan antigenemia despite clinical improvement. CAS improved survival, reduced pulmonary injury, and caused dose-dependent hyphal damage but with no reduction in residual fungal burden or galactomannan antigenemia in persistently neutropenic rabbits with invasive pulmonary aspergillosis.
Collapse
Affiliation(s)
- Ruta Petraitiene
- Immunocompromised Host Section, Pediatric Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
203
|
Vicente MF, Cabello A, Platas G, Basilio A, Díez MT, Dreikorn S, Giacobbe RA, Onishi JC, Meinz M, Kurtz MB, Rosenbach M, Thompson J, Abruzzo G, Flattery A, Kong L, Tsipouras A, Wilson KE, Peláez F. Antimicrobial activity of ergokonin A from Trichoderma longibrachiatum. J Appl Microbiol 2001; 91:806-13. [PMID: 11722657 DOI: 10.1046/j.1365-2672.2001.01447.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS Natural fungal products were screened for antifungal compounds. The mode of action of one of the hits found and the taxonomy of the producing organism were analysed. METHODS AND RESULTS An extract from a Trichoderma species showed a more potent activity in an agar-based assay against the null mutant fks1::HIS strain than against the wild-type strain, suggesting that it could contain a glucan synthesis inhibitor. The active component was identified as the known compound ergokonin A. The compound exhibited activity against Candida and Aspergillus species, but was inactive against Cryptococcus species. It induced alterations in the hyphal morphology of Aspergillus fumigatus. The identification of the producing isolate was confirmed by sequencing of the rDNA internal transcribed spacers and comparison with the sequences of other Trichoderma species. The analysis showed that the producing fungus had a high homology with other strains classified as Trichoderma longibrachiatum and its teleomorph Hypocrea schweinitzii. CONCLUSIONS The antifungal activity spectrum of ergokonin A and the morphology alterations induced on A. fumigatus are consistent with glucan synthesis as the target for ergokonin A. The production of ergokonin A is not uncommon, but is probably restricted to Trichoderma species. SIGNIFICANCE AND IMPACT OF THE STUDY The discovery that ergokonin A could be an inhibitor of glucan synthesis, having a structure very different to other inhibitors, increases the likelihood that orally active agents with this fungal-specific mode of action may be developed.
Collapse
Affiliation(s)
- M F Vicente
- Centro de Investigación Básica - Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de España, Madrid, Spain.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
206
|
Georgopapadakou NH. Update on antifungals targeted to the cell wall: focus on beta-1,3-glucan synthase inhibitors. Expert Opin Investig Drugs 2001; 10:269-80. [PMID: 11178340 DOI: 10.1517/13543784.10.2.269] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Currently available antifungal drugs for serious infections are either fungistatic and vulnerable to resistance (azoles) or fungicidal but toxic to the host (polyenes). Cell wall-acting antifungals are inherently selective and fungicidal, features that make them particularly attractive for clinical development. Three classes of such compounds, targeted respectively to chitin synthase (nikkomycins), beta-1,3-glucan synthase (echinocandins) and mannoproteins (pradimicins/benanomicins), have entered clinical development. While nikkomycins and pradimicins/benanomicins are no longer in development, echinocandins have emerged as potentially clinically useful and three compounds, caspofungin (MK-991, L-743,872), micafungin (FK-463) and anidulafungin (LY-303366) are in late clinical development (Phase II and III).
Collapse
Affiliation(s)
- N H Georgopapadakou
- DuPont Pharmaceuticals, Experimental Station, E400/3456A, P.O. Box 80400, Wilmington, DE 19880-0400, USA.
| |
Collapse
|
207
|
Dodds ES, Drew RH, Perfect JR. Antifungal pharmacodynamics: review of the literature and clinical applications. Pharmacotherapy 2000; 20:1335-55. [PMID: 11079283 DOI: 10.1592/phco.20.17.1335.34901] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Invasive fungal infections are seen with growing frequency, likely due to increases in numbers of patients at risk of infection. Optimal selection and dosing of antifungal agents are important, as these infections are often refractory to available therapy. In contrast to antibacterials, studies examining the pharmacodynamic properties of antifungals and their application in treating invasive disease often are lacking. Agents administered for invasive infections are amphotericin B, flucytosine, and azole antifungals. Several drugs are under investigation, such as posiconazole, voriconazole, and the echinocandins, and preliminary pharmacodynamic data likely will help shape dosing regimens. Clinical trials that investigated dosage and administration, as well as the potential benefits of combination and sequential therapy, are addressed. In addition, antifungal susceptibility and animal models of infection are discussed.
Collapse
Affiliation(s)
- E S Dodds
- Campbell University School of Pharmacy, Buies Creek, North Carolina, USA
| | | | | |
Collapse
|
208
|
Peláez F, Cabello A, Platas G, Díez MT, González del Val A, Basilio A, Martán I, Vicente F, Bills GE, Giacobbe RA, Schwartz RE, Onish JC, Meinz MS, Abruzzo GK, Flattery AM, Kong L, Kurtz MB. The discovery of enfumafungin, a novel antifungal compound produced by an endophytic Hormonema species biological activity and taxonomy of the producing organisms. Syst Appl Microbiol 2000; 23:333-43. [PMID: 11108011 DOI: 10.1016/s0723-2020(00)80062-4] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In a screening of natural products with antifungal activity derived from endophytic fungi, we detected a potent activity in a culture belonging to the form-genus Hormonema, isolated from leaves of Juniperus communis. The compound is a new triterpene glycoside, showing an antifungal activity highly potent in vitro against Candida and Aspergillus and with moderate efficacy in an in vivo mouse model of disseminated candidiasis. The agent is especially interesting since its antifungal spectrum and its effect on morphology of Aspergillus fumigatus is comparable to that of the glucan synthase inhibitor pneumocandin B,,, the natural precursor of the clinical candidate MK-0991 (caspofungin acetate). An additional search for other Hormonema isolates producing improved titers or derivatives resulted in the isolation of two more strains recovered from the same plant host showing identical activity. The producing isolates were compared with other non-producing Hormonema strains by DNA fingerprinting and sequencing of the rDNA internal transcribed spacers. Comparison of rDNA sequences with other fungal species suggests that the producing fungus could be an undetermined Kabatina species. Kabatina is a coelomycetous genus whose members are known to produce Hormonema-like states in culture.
Collapse
Affiliation(s)
- F Peláez
- Centro de Investigación Básica - Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de España, Madrid, Spain.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
210
|
Schwartz RE, Smith SK, Onishi JC, Meinz M, Kurtz M, Giacobbe RA, Wilson KE, Liesch J, Zink D, Horn W, Morris S, Cabello A, Vicente F. Isolation and Structural Determination of Enfumafungin, a Triterpene Glycoside Antifungal Agent That Is a Specific Inhibitor of Glucan Synthesis. J Am Chem Soc 2000. [DOI: 10.1021/ja9944296] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert E. Schwartz
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Scott K. Smith
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Janet C. Onishi
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Maria Meinz
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Myra Kurtz
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Robert A. Giacobbe
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Kenneth E. Wilson
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Jerrold Liesch
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Deborah Zink
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Wendy Horn
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Sandra Morris
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Angeles Cabello
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| | - Francisca Vicente
- Contribution from Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065-0900, and Centro de Investigacion Basica-Natural Products Drug Discovery, Merck Research Laboratories, Merck, Sharp and Dohme de Espana, S. A. Josefa Valcarel, 38. 28027 Madrid, Spain
| |
Collapse
|