Salvage Therapy of Refractory Chronic Disseminated Candidiasis in a Patient with Acute Myeloid Leukaemia and Secondary Prophylaxis During Allogeneic Stem Cell Transplantation

Caspofungin resistant disseminated candidiasis in a 7-year-old girl with T cell lymphoma: a case report

Immunocompromised patients are at increased risk of disseminated candidiasis. Guidelines for the treatment of invasive candidiasis were last published in 2009, but resistance to the recommended treatment has recently been described in the literature. Here we present the case of an immunocompromised child with T-cell lymphoma who died secondary to disseminated candidiasis despite prolonged antifungal therapy. Awareness of the increasing resistance patterns of Candida when caring for immunocompromised patients, especially pediatric patients, may improve treatment and create better patient outcomes.

Posaconazole: A new agent for the prevention and management of severe, refractory or invasive fungal infections

Posaconazole is the newest antifungal agent to be approved for use in Canada. With excellent in vitro activity against a broad spectrum of yeasts and filamentous fungi, as well as having a well-tolerated oral formulation, posaconazole offers many potential advantages. Of particular interest are its seemingly lower potential for cross-resistance with other azoles and its activity (unique among oral antifungal agents) against the zygomycetes. As the incidence of both common and uncommon fungal infections increases commensurate with the growing population of immunocompromised individuals, posaconazole may ultimately become an important therapeutic option. The present article reviews the in vitro and in vivo data describing its activity, and focuses on both the proven and the potential clinical applications of this new triazole agent.

Multilaboratory testing of two-drug combinations of antifungals against Candida albicans, Candida glabrata, and Candida parapsilosis

There are few multilaboratory studies of antifungal combination testing to suggest a format for use in clinical laboratories. In the present study, eight laboratories tested quality control (QC) strain Candida parapsilosis ATCC 22019 and clinical isolates Candida albicans 20533.043, C. albicans 20464.007, Candida glabrata 20205.075, and C. parapsilosis 20580.070. The clinical isolates had relatively high azole and echinocandin MICs. A modified CLSI M27-A3 protocol was used, with 96-well custom-made plates containing checkerboard pairwise combinations of amphotericin B (AMB), anidulafungin (AND), caspofungin (CSP), micafungin (MCF), posaconazole (PSC), and voriconazole (VRC). The endpoints were scored visually and on a spectrophotometer or enzyme-linked immunosorbent assay (ELISA) reader for 50% growth reduction (50% inhibitory concentration [IC(50)]). Combination IC(50)s were used to calculate summation fractional inhibitory concentration indices (FICIs) (ΣFIC) based on the Lowe additivity formula. The results revealed that the IC(50)s of all drug combinations were lower or equal to the IC(50) of individual drugs in the combination. A majority of the ΣFIC values were indifferent (ΣFIC = 0.51 to 2.0), but no antagonism was observed (ΣFIC ≥ 4). Synergistic combinations (ΣFIC ≤ 0.5) were found for AMB-PSC against C. glabrata and for AMB-AND and AMB-CSP against C. parapsilosis by both visual and spectrophotometric readings. Additional synergistic interactions were revealed by either of the two endpoints for AMB-AND, AMB-CSP, AMB-MCF, AMB-PSC, AMB-VRC, AND-PSC, CSP-MCF, and CSP-PSC. The percent agreements among participating laboratories ranged from 37.5% (lowest) for AND-CSP and POS-VOR to 87.5% (highest) for AMB-MCF and AND-CSP. Median ΣFIC values showed a wide dispersion, and interlaboratory agreements were less than 85% in most instances. Additional studies are needed to improve the interlaboratory reproducibility of antifungal combination testing.

Posaconazole: an oral triazole with an extended spectrum of activity

OBJECTIVE

To summarize the published clinical data on posaconazole, critically review the New Drug Application data submitted to the Food and Drug Administration, and provide information critical for evaluation and formulary positioning.

DATA SOURCES

Reported investigations were identified from MEDLINE (1966-June 30, 2008), bibliographies of manuscripts, www.clinicaltrials.gov, and www.fda.gov.

STUDY SELECTION AND DATA EXTRACTION

English-language articles were selected. All available in vitro, animal, clinical, and human studies describing the pharmacology, pharmacokinetics, pharmacodynamics, efficacy, safety, and adverse events of posaconazole were reviewed.

DATA SYNTHESIS

Posaconazole is an oral broad-spectrum triazole with activity against many yeasts and molds. Resistance to posaconazole has been reported, but has been rare to date. Posaconazole, in doses of 200 mg 3 times daily, reduced breakthrough invasive fungal infections (OR 0.30; 95% CI 0.12 to 0.71) and aspergillosis incidence (OR 0.31; 95% CI 0.13 to 0.75) in patients receiving hematopoietic stem-cell transplants compared with those receiving fluconazole. Similarly, the same regimen of posaconazole reduced invasive fungal infections (95% CI -9.7 to -2.5) and aspergillosis (CI not reported, p < 0.001) when compared with fluconazole and itraconazole in neutropenic patients. Posaconazole is noninferior to fluconazole for treatment of oropharyngeal candidiasis (95% CI -6.6 to 5.0), but necessity for this indication remains unclear, as many other treatment options exist. Smaller investigations have analyzed use of posaconazole for patients requiring salvage or alternative treatment for zygomycosis, fusariosis, cryptococcal meningitis, coccidioidomycosis, and histoplasmosis. Studies are needed to clarify efficacy for such expanded use, and therapeutic drug monitoring may improve outcomes. The most common adverse effects associated with the use of posaconazole include headache, fever, nausea, vomiting, and diarrhea.

CONCLUSIONS

Posaconazole appears to be a valuable and promising addition to the antifungal armamentarium for prophylaxis and treatment of various fungal processes. At this time, posaconazole should probably be reserved for prophylaxis in patients at high risk for invasive fungal infection, as salvage therapy in refractory or resistant infections, or for patients with intolerance to other therapies.