sirolimus and Aspergillosis

We assessed predictive factors and characteristics of patients with late-onset invasive aspergillosis in the current era of novel immunosuppressive agents. Forty transplant recipients with invasive aspergillosis were included in this prospective, observational study initiated in 2003 at our institutions. In 50% (20/40) of these patients, the infections were late-occurring. Receipt of sirolimus in conjunction with tacrolimus for refractory rejection or cardiac allograft vasculopathy (P=0.047) was significantly associated with late-onset infection. The use of depleting or non-depleting T or B-cell antibodies, either as induction or as antirejection therapy did not correlate with time to onset of invasive aspergillosis. Mortality at 90 days was 20% (4/20) for the patients with early-onset infection and 45% (9/20) for those with late-onset infection (P=0.17). Thus, nearly one-half of the Aspergillus infections in transplant recipients in the current era are late-occurring. These data have implications relevant for prophylactic strategies and guiding clinical management of transplant recipients presenting with pulmonary infiltrates.

Topics: Adult; Age of Onset; Aged; Antibodies; Antifungal Agents; Aspergillosis; B-Lymphocytes; Drug Therapy, Combination; Female; Humans; Immunosuppressive Agents; Male; Middle Aged; Organ Transplantation; Postoperative Complications; Prospective Studies; Risk Factors; Sirolimus; Spain; T-Lymphocytes; Tacrolimus; Treatment Outcome; United States

The serine-threonine kinase TOR, the Target of Rapamycin, is an important regulator of nutrient, energy and stress signaling in eukaryotes. Sch9, a Ser/Thr kinase of AGC family (the cAMP-dependent PKA, cGMP- dependent protein kinase G and phospholipid-dependent protein kinase C family), is a substrate of TOR. Here, we characterized the fungal opportunistic pathogen Aspergillus fumigatus Sch9 homologue (SchA). The schA null mutant was sensitive to rapamycin, high concentrations of calcium, hyperosmotic stress and SchA was involved in iron metabolism. The ΔschA null mutant showed increased phosphorylation of SakA, the A. fumigatus Hog1 homologue. The schA null mutant has increased and decreased trehalose and glycerol accumulation, respectively, suggesting SchA performs different roles for glycerol and trehalose accumulation during osmotic stress. The schA was transcriptionally regulated by osmotic stress and this response was dependent on SakA and MpkC. The double ΔschA ΔsakA and ΔschA ΔmpkC mutants were more sensitive to osmotic stress than the corresponding parental strains. Transcriptomics and proteomics identified direct and indirect targets of SchA post-exposure to hyperosmotic stress. Finally, ΔschA was avirulent in a low dose murine infection model. Our results suggest there is a complex network of interactions amongst the A. fumigatus TOR, SakA and SchA pathways.

Topics: Animals; Aspergillosis; Aspergillus fumigatus; Female; Fungal Proteins; MAP Kinase Signaling System; Mice; Mice, Inbred BALB C; Mitogen-Activated Protein Kinases; Osmotic Pressure; Oxidative Stress; Phosphorylation; Protein Serine-Threonine Kinases; Signal Transduction; Sirolimus; Spores, Fungal; TOR Serine-Threonine Kinases; Virulence

Allogeneic hematopoietic stem cell transplant (HSCT) recipients are at high risk for invasive aspergillosis. Whereas adoptive immunotherapy transferring donor-derived anti-Aspergillus TH1 cells has been shown to be beneficial for HSCT recipients suffering from invasive aspergillosis, little is known about the impact of commonly used immunosuppressants on the functional properties of anti-Aspergillus TH1 cells. Anti-Aspergillus TH1 cells were coincubated with different concentrations of methylprednisolone, cyclosporine (CsA), mycophenolic acid (MPA), the active component of mycophenolate mofetil, and rapamycin. Immunosuppressants were tested in concentrations reflecting common target levels in serum and in significantly lower and higher concentrations. Apoptosis of anti-Aspergillus TH1 cells, as well as proliferation and production of gamma interferon (IFN-γ) and CD154 upon restimulation, was evaluated in the presence and absence of immunosuppressive compounds. All dosages of CsA, MPA, and methylprednisolone significantly decreased the number of viable anti-Aspergillus TH1 cells in the cell culture, which was due partly to an impaired proliferative capacity of the cells and partly to an increased rate of apoptosis. In addition, CsA significantly decreased the number of IFN-γ-producing cells and had the highest impact of all immunosuppressants on IFN-γ levels in the supernatant. CsA also significantly decreased the expression of CD154 by anti-Aspergillus TH1 cells. Variant dosages of immunosuppressants exhibit particular effects on essential functional properties of anti-Aspergillus TH1 cells. Our findings may have an important impact on the design of clinical trials evaluating the therapeutic benefit of anti-Aspergillus TH1 cells in allogeneic HSCT recipients suffering from invasive aspergillosis.

Topics: Apoptosis; Aspergillosis; Aspergillus fumigatus; Cell Proliferation; Cells, Cultured; Cyclosporine; Cytokines; Humans; Immunosuppressive Agents; Interferon-gamma; Methylprednisolone; Mycophenolic Acid; Sirolimus; Th1 Cells

We report a case of a 54-year-old male renal transplant patient who received antifungal azole treatment in combination with the recently introduced immunosuppressant agent everolimus to prevent post-transplantation aspergillosis reactivation. Voriconazole was withdrawn after 1 month because of elevated concentrations (5 mg/L trough plasma determination) and hepatotoxicity, and substituted by several months of treatment with posaconazole (observed concentration range 1-2 mg/L). We observed pharmacokinetic drug interactions between both voriconazole and posaconazole, and everolimus cytochrome P450 3A4 metabolism, resulting in 7.5- and 3.8-fold increase, respectively, in everolimus blood trough concentrations. Combined therapeutic drug monitoring (TDM) of both everolimus and azole inhibitors allowed for safe and convenient modification of everolimus dosage, which was tapered to maintain a target range of 5-15 ng/mL during and after antifungal treatments. While significant in their effects, these drug interactions were able to be managed safely through a careful approach to management and use of individual TDM.

Topics: Antifungal Agents; Aspergillosis; Cytochrome P-450 CYP3A; Drug Interactions; Drug Monitoring; Everolimus; Humans; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Pyrimidines; Sirolimus; Triazoles; Voriconazole

To describe the management of a pharmacokinetic interaction between azole antifungals (fluconazole and voriconazole) and everolimus in a patient who underwent an orthotopic liver transplant.. A 65-year-old male who received an orthotopic liver transplant experienced an iatrogenic retroperitoneal duodenal perforation on postoperative day 55. His condition was subsequently complicated by severe sepsis and acute renal failure. Intravenous fluconazole 400 mg, followed by 100 mg every 24 hours according to impaired renal function, was immediately started; to avoid further nephrotoxicity, immunosuppressant therapy was switched from cyclosporine plus mycophenolate mofetil to oral everolimus 0.75 mg every 12 hours. Satisfactory steady-state minimum concentration (C(min)) of everolimus was achieved (approximately 5 ng/mL). On day 72 posttransplant, because of invasive aspergillosis, antifungal therapy was switched to intravenous voriconazole 400 mg every 12 hours on the first day, followed by 200 mg every 12 hours; to prevent drug toxicity, the everolimus dosage was promptly lowered to 0.25 mg every 24 hours. At that time, the everolimus C(min) averaged approximately 3 ng/mL. The concentration/dose ratio of everolimus (ie, C(min) reached at steady-state for each milligram per kilogram of drug administered) was markedly lower during fluconazole versus voriconazole cotreatment (mean +/- SD, 3.49 +/- 0.29 vs 11.05 +/- 0.81 ng/mL per mg/kg/daily; p < 0.001). Despite intensive care, the patient's condition continued to deteriorate and he died on day 84 posttransplant.. Both azole antifungals were considered probable causative agents of an interaction with everolimus according to the Drug Interaction Probability Scale. The interaction is due to the inhibition of CYP3A4-mediated everolimus clearance. Of note, prompt reduction of the everolimus dosage since the first azole coadministration, coupled with intensive therapeutic drug monitoring, represented a useful strategy to prevent drug overexposure.. Our data suggest that during everolimus-azole cotreatment, a dose reduction of everolimus is needed to avoid overexposure. According to the different inhibitory potency of CYP3A4 activity, the reduction should be lower during fluconazole than during voriconazole cotreatment.

Topics: Aged; Antifungal Agents; Aspergillosis; Drug Interactions; Everolimus; Fatal Outcome; Fluconazole; Humans; Immunosuppressive Agents; Liver Transplantation; Male; Pyrimidines; Sirolimus; Triazoles; Voriconazole

Voriconazole is currently contraindicated for use with sirolimus. We report our experience with voriconazole/sirolimus in two renal transplant recipients. To our knowledge, this is the first experience with voriconazole/sirolimus. An interaction requiring a 75% to 87.5% sirolimus dose reduction was noted, but goal trough levels and clinical tolerability were achieved.

Topics: Adult; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Candidiasis; Female; Humans; Immunosuppressive Agents; Kidney Transplantation; Lung Diseases, Fungal; Male; Middle Aged; Postoperative Complications; Pyrimidines; Sirolimus; Triazoles; Voriconazole

Aspergillus fumigatus is the predominant mold pathogen in patients who lack functional innate immunity. The A. fumigatus rhbA gene was first identified as a transcript that was upregulated when the organism was grown in the presence of mammalian cells. To gain insight into the function of rhbA in the growth and pathogenesis of A. fumigatus, we constructed a strain that lacks a functional rhbA gene. The Delta rhbA mutant showed a significant reduction in virulence compared to the virulence of the wild type in a mouse model of invasive aspergillosis. Complementation of the deletion with the wild-type gene restored full virulence. Although the Delta rhbA mutant grew as well as the wild type on solid medium containing the rich nitrogen source ammonium, the growth of the mutant was impaired on medium containing poor nitrogen sources. Like the Saccharomyces cerevisiae rhb1 mutant, the Delta rhbA mutant exhibited increased uptake of arginine. In addition, the Delta rhbA strain underwent asexual development in submerged cultures, even under ammonium-excess conditions. Growth of the mutant with poor nitrogen sources eliminated both the arginine uptake and submerged asexual development phenotypes. The mutant showed enhanced sensitivity to the TOR kinase inhibitor rapamycin. These findings establish the importance of rhbA for A. fumigatus virulence and suggest a role for rhbA in nutrient sensing.

Topics: Animals; Arginine; Aspergillosis; Aspergillus fumigatus; Disease Models, Animal; Female; Fungal Proteins; Lung Diseases, Fungal; Mice; Monomeric GTP-Binding Proteins; Nitrogen; Sirolimus; Virulence

Cyclosporin A, tacrolimus, and sirolimus are immunosuppressive agents initially described as antifungal compounds with different activities for Aspergillus species. The outcome of invasive aspergillosis in mice treated with each agent was investigated in outbred CD-1 mice. Immunosuppressant or vehicle alone was administered from days -1 to +14. Mice were infected on day 0 with resting Aspergillus conidia via lateral tail vein injection. Survival was significantly greater with most regimens than for mice treated with cyclosporin A (100 mg/kg/day; median survival, 3 days): tacrolimus, 1 mg/kg/day (6.5 days, P = .003); sirolimus, 1 or 10 mg/kg/day (7.5 and 9.5 days, respectively; P = .002 and .0001); and vehicle alone (6.5 days, P = .001). However, mice treated with 10 mg/kg/day of tacrolimus survived a median of 4.5 days (P = .25). Survival in the 10-mg sirolimus group did not differ from that of mice given vehicle alone (P = .55). Histologic evaluation suggested the improved survival with tacrolimus and sirolimus may be due in part to direct anti-Aspergillus activity.

Topics: Animals; Antifungal Agents; Aspergillosis; Aspergillus; Brain; Cyclosporine; Immunosuppressive Agents; Mice; Polyenes; Sirolimus; Tacrolimus