sirolimus and posaconazole

We describe the first successful case of posaconazole salvage therapy for mucormycosis with concomitant sirolimus (SRL) maintenance immunosuppression following liver transplantation, despite black box drug interaction following intolerance to first-line tacrolimus and amphotericin due to nephrotoxicity and neurotoxicity. This case describes a 55-year-old female who developed rhinocerebral mucormycosis 108 days after liver transplantation. After 3 months of posaconazole therapy, the patient remains free of disease at 3 years posttransplant. This case report illustrates successful resolution of mucormycosis without SRL toxicity to resolve nephrotoxicity of long-term amphotericin on top of already nephrotoxic immunosuppression. With higher bioavailability of recently FDA-approved posaconazole delayed release tablets, this azole may be a therapeutic option for transplant patients who need to remain on CYP3A4-metabolized immunosuppressive agents.

Topics: Antifungal Agents; Female; Humans; Immunosuppressive Agents; Liver Transplantation; Maintenance Chemotherapy; Middle Aged; Mucormycosis; Salvage Therapy; Sirolimus; Treatment Outcome; Triazoles

Azole antifungal agents are often coadministered with immunosuppressants to recipients of solid organ and hematopoietic stem cell transplants. Posaconazole, an extended-spectrum triazole, is an inhibitor of the cytochrome P450 (CYP) isoenzyme CYP3A4, and sirolimus, an immunosuppressant, is a substrate of the enzyme. We evaluated the effects of posaconazole on sirolimus pharmacokinetics in an open-label, multiperiod, drug-interaction study.. Twelve healthy subjects received one dose of sirolimus 2 mg on day 1. After a 28-day washout period, subjects received posaconazole 400 mg bid for 16 days (to day 45). On day 36, sirolimus 2 mg and posaconazole 400 mg were coadministered. Blood samples to determine sirolimus plasma concentrations were collected up to 216 hours post dose on days 1 and 36 and plasma pharmacokinetic parameters were calculated. Drug interactions were evaluated using one-way analysis of variance. Mean (% coefficient of variation) maximum plasma concentration (C(max)) and area under the curve (AUC) of sirolimus at day 1 were 4.9 ng/mL (38) and 145 h x ng/mL (45), respectively.. Coadministration with posaconazole increased sirolimus C(max) and AUC by 6.7- and 8.9-fold, respectively. These increases are consistent with CYP3A4 inhibition by posaconazole. Adverse events were reported by five subjects (42%) receiving posaconazole and sirolimus and by three (25%) and eight (67%) subjects receiving posaconazole only on days 30 to 35 (presirolimus) and days 37 to 45 (postsirolimus), respectively.. Because posaconazole has a clinically relevant effect on sirolimus exposure, the agents should probably not be coadministered. Although this was a descriptive study, one potential limitation was the small sample size. The conclusion could have been made stronger if the number of people enrolled in the study had been greater.

Topics: Administration, Oral; Adolescent; Adult; Antifungal Agents; Area Under Curve; Female; Humans; Immunosuppressive Agents; Male; Middle Aged; Reference Values; Sirolimus; Triazoles; Young Adult

Topics: Antifungal Agents; Aspergillus; Azoles; Candida; Candida albicans; Drug Resistance, Fungal; Exophiala; Fungi; Humans; Itraconazole; Microbial Sensitivity Tests; Morpholines; Sirolimus; TOR Serine-Threonine Kinases; Triazoles; Voriconazole

Topics: Adolescent; Adult; Aged; Female; Follow-Up Studies; Hematopoietic Stem Cell Transplantation; Hodgkin Disease; Humans; Leukemia, Myeloid, Acute; Lymphoma, Non-Hodgkin; Male; Middle Aged; Multiple Myeloma; Remission Induction; Risk; Sirolimus; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome; Triazoles; Young Adult

Allogeneic hematopoietic stem cell transplant patients are at risk of invasive fungal infections and prophylaxis with azole agents is common practice. The concomitant use of these agents with sirolimus and tacrolimus for the prevention of graft-versus-host disease may result in excessive immunosuppression or toxicity.. This retrospective study identified hospitalized patients who underwent allogeneic hematopoietic stem cell transplantation between August 2009 and April 2011 at Rush University Medical Center. From this group, patients who underwent concomitant tacrolimus, sirolimus, and azole therapy were included for evaluation. The immunosuppression dosing in conjunction with azole use at discharge was analyzed to develop a dosing algorithm dependent on whether fluconazole, posaconazole, or voriconazole was used.. A total of 36 patients were screened for inclusion, of which 8 were excluded due to acute renal failure and/or hemolysis. The remaining patients were stratified by the azole they were concomitantly taking with tacrolimus and sirolimus. The fluconazole arm required the lowest magnitude of dose reductions, while voriconazole required the greatest.. Dose reductions of 50-75% for both sirolimus and tacrolimus, in combination with standard dosing of azole antifungal agents, were necessary to achieve therapeutic drug concentrations for immunosuppressants and potentially avoid toxicities.

Topics: Adult; Aged; Algorithms; Antifungal Agents; Azoles; Drug Dosage Calculations; Female; Fluconazole; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Male; Middle Aged; Mycoses; Retrospective Studies; Sirolimus; Tacrolimus; Triazoles; Voriconazole; Young Adult

To determine an appropriate empiric oral sirolimus dose adjustment when given concurrently with posaconazole oral suspension in patients who undergo hematopoietic stem cell transplant (HSCT).. Retrospective cohort study.. Comprehensive cancer center in the United States.. Seventy five allogeneic HSCT patients who received posaconazole oral suspension and oral sirolimus concurrently between 2009 and 2011.. Sirolimus concentrations were recorded at baseline and for up to 28 days after posaconazole initiation. The sirolimus concentration/dose (C/D) ratio was determined for each sirolimus concentration obtained. Following analysis of patient data and based on the initial empiric sirolimus dose reduction, patients were stratified into two groups: ≥50% sirolimus dose reduction (Group 1) and <50% sirolimus dose reduction (Group 2). The mean sirolimus C/D ratio was 2.29 ng/mL/mg prior to posaconzole initiation. Coadministration of posaconazole and sirolimus resulted in an increase in the steady state sirolimus C/D ratio to 6.24 ng/mL/mg, which occurred approximately 17-20 days after initiation of posaconazole. The mean maximum sirolimus concentration was significantly higher in Group 2 compared to Group 1 (12.64 ng/mL vs. 9.24 ng/mL, p=0.001). Significantly more patients in Group 2 than Group 1 experienced at least one sirolimus concentration >15 ng/mL (27% vs. 2.6%, p=0.003).. Coadministration of posaconazole oral suspension with oral sirolimus increases the sirolimus C/D ratio by approximately 2.7-fold in HSCT patients. An initial empiric oral sirolimus dose reduction between 50% and 65% may be recommended for most clinically stable patients with close sirolimus concentration monitoring for at least 3 weeks following posaconazole initiation.

Topics: Adult; Aged; Antifungal Agents; Drug Interactions; Female; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Male; Middle Aged; Retrospective Studies; Sirolimus; Triazoles; Young Adult

Sirolimus is used in allogeneic hematopoietic stem cell transplants (HSCTs) for prevention and treatment of graft-versus-host disease (GVHD). Posaconazole is used in this population for invasive fungal disease (IFD) prophylaxis and treatment. As posaconazole strongly inhibits CYP3A4, concurrent administration of sirolimus, a CYP3A4 substrate, and posaconazole has been reported to increase sirolimus drug exposure substantially. Coadministration of posaconazole and sirolimus is contraindicated by the manufacturer of posaconazole. We identified 15 patients who underwent HSCTs at our institution receiving a steady-state dose of sirolimus who subsequently started posaconazole therapy from January 2006 to March 2009. We recorded baseline characteristics, drug administration details, and potential adverse effects related to either drug. All patients underwent HSCTs for treatment of hematologic malignancy. All patients were initially prescribed sirolimus for GVHD prophylaxis and continued therapy after developing GVHD. Twelve patients (80%) received posaconazole for IFD prophylaxis in the setting of GVHD and 3 (20%) for IFD treatment. Patients received sirolimus and posaconazole concurrently for a median of 78 days (interquartile range [IQR] 25-177; range, 6-503). The median daily dose of sirolimus (2 mg/day) before initiation of posaconazole was reduced 50% to a median daily dose of 1 mg/day at steady state. Six patients experienced sirolimus trough levels greater than 12 ng/mL during coadministration, but only 1 patient experienced an adverse event potentially associated with sirolimus exposure during the first month of coadministration. This patient's sirolimus dose was empirically reduced by only 30% on posaconazole initiation. Concurrent sirolimus and posaconazole use seems to be well tolerated with a 33% to 50% empiric sirolimus dose reduction and close monitoring of serum sirolimus trough levels at the time of posaconazole initiation.

Topics: Adult; Antifungal Agents; Drug Administration Schedule; Drug Dosage Calculations; Drug Synergism; Drug Therapy, Combination; Female; Graft vs Host Disease; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Male; Middle Aged; Mycoses; Sirolimus; Transplantation, Homologous; Triazoles

Zygomycosis is an uncommon but devastating disease with few therapeutic options. Calcineurin inhibitors and sirolimus (mTOR inhibitor), commonly used in transplant patients as immunosuppressives, have antifungal activity. They are known to demonstrate synergy with triazoles against certain fungi, though limited data exist about their activity against zygomycetes. Our aim was to study the in vitro interaction of posaconazole with calcineurin inhibitors and sirolimus against zygomycetes.. Drug interactions were assessed with chequerboard dilution for posaconazole with calcineurin inhibitors and sirolimus according to the CLSI M38-A2 method for filamentous fungi. Twenty-eight clinical isolates were studied, including Rhizopus arrhizus, Rhizopus microsporus, Rhizomucor pusillus, Mucor sp., Cunninghamella bertholletiae, Myocladus corymbifera and Apophysomyces elegans. Combinations of posaconazole with tacrolimus, cyclosporin A or sirolimus were used. Experiments were performed in duplicate. Mean fractional inhibitory concentration indices were calculated.. Posaconazole with calcineurin inhibitors demonstrated consistent synergy against C. bertholletiae, M. corymbifera and A. elegans, whereas synergy or no interaction was primarily observed against R. arrhizus, R. microsporus, R. pusillus and Mucor. Antagonism was seen with the combination of posaconazole and sirolimus. Strain variability was noted among the same species.. The clinical significance of these findings is unclear, but further studies are warranted given the potential for concomitant use of these agents in transplant patients treated for zygomycosis.

Topics: Antifungal Agents; Calcineurin; Cyclosporine; Drug Interactions; Humans; Mucorales; Sirolimus; Tacrolimus; Triazoles

The in vitro interaction of antifungals with immunosuppressive drugs was evaluated against zygomycetes. The combination of amphotericin B with cyclosporine, rapamycin, or tacrolimus was synergistic for 90%, 70%, and 30% of the isolates, respectively. For posaconazole, itraconazole, and ravuconazole, synergy was more frequently observed with cyclosporine than with rapamycin or tacrolimus and antagonistic interactions were rarely noted. In summary, calcineurin inhibitors and rapamycin can be synergistic in vitro with amphotericin B and azoles against zygomycetes.

Topics: Amphotericin B; Antifungal Agents; Azoles; Cyclosporine; Drug Interactions; Immunosuppressive Agents; Itraconazole; Microbial Sensitivity Tests; Mucorales; Rhizopus; Sirolimus; Tacrolimus; Thiazoles; Triazoles

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

Calcineurin inhibitors may augment the effects of antifungal drugs in microbiological assays. We examined this interaction in a microbiological assay for posaconazole. No effect was observed. However, concurrent or recently discontinued treatment with other antifungal drugs caused false-positive results, emphasizing a limitation of microbiological assays for antifungal drug level measurement.

Topics: Antifungal Agents; Calcineurin Inhibitors; Cyclosporine; Drug Interactions; False Positive Reactions; Graft vs Host Disease; Humans; Immunosuppressive Agents; Microbiological Techniques; Sirolimus; Tacrolimus; Triazoles