Posaconazole Levels Research Articles

Is Posaconazole Really Effective in Adolescent patients as a Prophylactic Agent: Experience of a Tertiary Care Center

Invasive fungal infections (IFIs) are a leading cause of morbidity and death in immunocompromised patients. Data on efficacy and pharmacokinetics of posaconazole in pediatric patients are rare (1 to 5). Herein, we retrospectively analyzed adolescent patients who had received posaconazole as antifungal prophylaxis. We retrospectively analyzed patients who received posaconazole as primary or secondary antifungal prophylaxis. A total of 34 adolescent patients, 19 men (55.9%) and 15 women (44.1%) with a mean age of 15.8±2.1 years were included. Twenty-five of 34 (73.5%) patients were on primary and nine of 34 (26.5%) patients were on secondary antifungal prophylaxis. Diagnosis of the patients receiving posaconazole as primary antifungal prophylaxis were acute myeloid leukemia (n=12, 48%), hematopoietic stem cell transplantation (n=7, 28%), acute lymphoblastic leukemia (n=5, 20%), and Fanconi aplastic anemia (n=1, 4%). Five patients (55.6%) with hematopoietic stem cell transplantation, 1 patient with acute myeloid leukemia (11.1%), 1 patient with Fanconi aplastic anemia (11.1%), and 2 (22.2%) patients with chronic granulomatous disease received posaconazole as secondary antifungal prophylaxis. Twelve of 25 (48%) patients receiving posaconazole as primary antifungal prophylaxis were complicated by IFI; 4 of them were proven, 6 probable, and 2 with possible IFI. Three of 9 patients (33.3%) receiving posaconazole as secondary antifungal prophylaxis was complicated by IFI (P=0.29), 2 of them were probable and 1 was possible IFI. Five of 25 patients (20%) receiving posaconazole as primary prophylaxis died because of IFI. Improvement of antifungal prophylaxis in patients with high risk of invasive infections seems clearly necessary, and analyzing serum posaconazole levels and individualizing dosing may be 1 approach to improve outcomes.

Clinical considerations on posaconazole administration and therapeutic drug monitoring in allogeneic hematopoietic cell transplant recipients.

There is a paucity of data on posaconazole (PCZ) dosing and therapeutic-drug-monitoring (TDM) in allogeneic hematopoietic cell transplant recipients (allogeneic-HCTr). This was a 3-year retrospective multicenter study (January 1, 2016 to December 31, 2018) in adult allogeneic-HCTr who received PCZ (intravenously, IV and/or as delayed-release tablet, DRT) as prophylaxis or treatment for≥7 consecutive days (D) with at least 1-PCZ-level available using data of the Swiss Transplant Cohort Study. The primary objective was to describe the distribution of PCZ-level and identify predictors of therapeutic PCZ-level and associations between PCZ-dosing and PCZ-level. A total of 288 patients were included: 194 (67.4%) and 94 (32.6%) received PCZ as prophylaxis and treatment, respectively, for a median of 90 days (interquartile range, IQR: 42-188.5). There were 1944 PCZ-level measurements performed, with a median PCZ level of 1.3mg/L (IQR: 0.8-1.96). PCZ-level was<0.7mg/L in 383/1944 (19.7%) and<1.0mg/L in 656/1944 (33.7%) samples. PCZ-level was<0.7mg/L in 260/1317 (19.7%) and<1.0mg/L in 197/627 (31.4%) in patients who received PCZ-prophylaxis versus treatment, respectively. There were no significant differences in liver function tests between baseline and end-of-treatment. There were nine (3.1%) breakthrough invasive fungal infections (bIFI), with no difference in PCZ levels between patients with or without bIFI. Despite a very intensive PCZ-TDM, PCZ-levels remain below target levels in up to one-third of allogeneic-HCTr. Considering the low incidence of bIFI observed among patients with PCZ levels in the targeted range, our data challenge the clinical utility of routine universal PCZ-TDM.

Pharmacokinetics and tolerability of intravenous posaconazole in healthy Chinese volunteers: a randomized, open-label and single-dose study.

Posaconazole is a triazole antifungal drug with strong antifungal effect. The pharmacokinetics, safety, and tolerability were evaluated following the intravenous administration of posaconazole injection. A total of 36 healthy adults were enrolled in the parallel-designed clinical trial, and the subjects received single doses of posaconazole injection (100, 200 and 300 mg). Posaconazole concentrations in plasma were determined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The levels of posaconazole in plasma increased proportionally between 100 and 300-mg dose, but AUC showed a more-than-dose-proportional increase. Besides, decreased Vd and CL were observed, along with the increased posaconazole dosage. Posaconazole was well tolerated at all dose levels, and the adverse events were not dose dependent. No clinically significant changes in electrocardiograms were observed.

Incidence of Invasive Fungal Infections in Acute Leukemia Patients Utilizing Micafungin Prophylaxis Compared to Second-Generation Azole Prophylaxis

Introduction/Background: Standard therapy for both acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) is myelosuppressive, and patients are expected to be neutropenic for a prolonged period. Due to the high risk of infection, antimicrobial prophylaxis is warranted and should be continued throughout neutropenia. The incidence of documented invasive fungal infections ranges from 12 to 24% in patients with AML and approximately 6.5% in patients with ALL. Guidelines currently include posaconazole as a category 1 recommendation for antifungal prophylaxis, with echinocandins and other azole antifungals as category 2B. However, posaconazole can be subject to drug-drug interactions and can increase the risk of hepatotoxicity, both of which can be problematic in acute leukemia patients undergoing chemotherapy. For patients unable to receive posaconazole or another second-generation azole antifungal, micafungin is utilized. To our knowledge, there are no studies comparing second-generation azole antifungals to micafungin as prophylaxis in both AML and ALL during initial or relapsed/refractory induction therapy. The aim of this retrospective study is to compare the incidence of invasive fungal infections in patients with acute leukemia in the setting of micafungin or second-generation azole antifungal prophylaxis during initial and/or relapsed/refractory induction therapy at an academic medical center. Methods: Retrospective, single-center study from June 22, 2013 to June 22, 2018. Detailed chart reviews were performed by hand. Results: The incidence of invasive fungal infections within 100 days of chemotherapy was 11.2% in patients who received a second-generation azole and 2.7% in patients who received micafungin (P=0.7618). The incidence of invasive fungal infections within 100 days in patients who received a high intensity AML regimen was 11.2%, low intensity AML regimen 0.9%, and ALL regimen 1.8% (P=0.5378). The incidence of invasive fungal infections within 30 days of chemotherapy was 4.5% in patients who received a second-generation azole and 2.2% in patients who received micafungin (P=0.2447). The most common reason for micafungin prophylaxis was drug-drug interactions with standard ALL regimens that utilize vincristine. Of those with a documented fungal infection, 14 patients (6.3%) had a proven invasive fungal infection, and 17 patients (7.6%) had a probable/possible invasive fungal infection. The most common site of infection was in the chest (9.8%), followed by fungemia (2.2%). Other sites of infection include the brain, sinuses, liver/spleen, and skin. Beta-D-glucan was collected in 17 patients, and galactomannan antigen was collected in 26 patients. Three patients had a positive beta-D-glucan, and 1 patient had an indeterminate beta-D-glucan. Two patients had a positive galactomannan antigen. Fusarium species accounted for 4 positive cultures in patients. For those patients who did experience an invasive fungal infection, 23 out of the 31 patients (74.2%) were on posaconazole, 6 patients on micafungin (19.4%), and 2 on voriconazole (6.5%). Ten out of the 14 proven fungal infections (71.4%) occurred while on posaconazole prophylaxis, and 3 of these patients had posaconazole levels &lt;0.7 mcg/mL. Twenty-one patients (67.7%) with documented infections had a neutrophil nadir &lt; 0.1x109/L. The majority (93.5%) of those with breakthrough infections while on antifungal prophylaxis were switched to another antifungal. Conclusions: Micafungin is a reasonable alternative therapy for use in patients who are unable to receive second-generation azoles as antifungal prophylaxis during induction therapy for acute leukemia. Some invasive fungal infections occurred while patients had sub-therapeutic posaconazole levels, however others had breakthrough fungal infections with therapeutic levels. Our conclusions are limited by the small sample size and non-randomized, retrospective nature of this analysis. Disclosures Erba: Agios, Amgen, Astellas Pharma, Daiichi Sankyo, ImmunoGen, Janssen, Jazz Pharmaceuticals, Juno, Millennium, Seattle Genetics: Research Funding; Celgene, Incyte, Novartis: Speakers Bureau; Amgen, Celgene, Daiichi Sankyo, ImmunoGen, Incyte, Jazz Pharmaceuticals, Millennium, Novartis, Ono, Pfizer, Seattle Genetics, Sunesis: Consultancy. LeBlanc:Seattle Genetics: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees; Agios: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; NINR/NIH: Research Funding; Jazz Pharmaceuticals: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; CareVive: Consultancy; American Cancer Society: Research Funding; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Helsinn: Consultancy; Medtronic: Membership on an entity's Board of Directors or advisory committees; Otsuka: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer Inc: Consultancy; Heron: Membership on an entity's Board of Directors or advisory committees; Duke University: Research Funding; Celgene: Honoraria; Flatiron: Consultancy. Rizzieri:AROG, Bayer, Celgene, Celltron, Mustang, Pfizer, Seattle Genetics, Stemline: Consultancy; Stemline: Research Funding; Celgene, Gilead, Seattle Genetics, Stemline: Other: Speaker; AbbVie, Agios, AROG, Bayer, Celgene, Gilead, Jazz, Novartis, Pfizer, Sanofi, Seattle Genetics, Stemline, Teva: Other: Advisory Board.

1737. Impact of Therapeutic Drug Monitoring (TDM) of Azole Prophylaxis in Lung Transplant Recipients on the Development of Positive Fungal Events

BackgroundThe utility and clinical impact of therapeutic drug monitoring (TDM) of prophylactic azole antifungals in lung transplant recipients is not well described. The objective of this study was to investigate the impact of TDM of azole prophylaxis in lung transplant recipients on the development of positive fungal events.MethodsA retrospective analysis was performed on 47 lung transplant recipients between 2013 and 2018 at Northwestern Memorial Hospital. A positive fungal event was defined as fungal species on BAL culture and/or positive BAL Aspergillus galactomannan (GM) with an index value ≥1.0. Study groups were defined based on attainment of therapeutic trough levels after initiation of oral therapy (therapeutic if posaconazole level ≥0.7 μg/mL or voriconazole ≥1–5.5 μg/mL, subtherapeutic if ≥2 consecutive levels of posaconazole <0.7 μg/mL or voriconazole <1 μg/mL after initial dose increase).ResultsThere were no differences in baseline characteristics (Figure 1). There were a total of 11 fungal events with 3 (12.0%) occurring in the therapeutic cohort and 8 (36.4%) in those subtherapeutic (P = 0.08). In the 5 patients with a positive GM, the mean index was 2.02 ± 0.95. 7/30 (23.3%) of patients on posaconazole had a fungal event, with 2/7 (28.6%) requiring treatment at the time of event. For patients on voriconazole, 4/17 (23.5%) had a fungal event, with 1/4 (25.0%) requiring treatment. Mean time to fungal event was 164.5 ± 8.9 days vs. 135.9 ± 13.7 days in the therapeutic and subtherapeutic group, respectively (P = 0.05).All patients on posaconazole suspension who experienced a fungal event were subtherapeutic (3/3, 100%) compared with the majority of patients on posaconazole delayed release (DR) tablets who achieved therapeutic levels (17/22, 77.3%). Mean posaconazole trough level observed in the patients receiving DR tablet was 2.15 ± 0.95 μg/mL.ConclusionThere was an association between two consecutive subtherapeutic azole prophylaxis levels and positive fungal events indicating a role for TDM in lung transplant recipients. Time to fungal event post-transplant was shorter in subtherapeutic patients. As anticipated, the use of posaconazole suspension resulted in subtherapeutic levels. This study presents an opportunity for further research of the impact of TDM on clinical outcomes to optimize patient care. Disclosures All authors: No reported disclosures.

732. Posaconazole Serum Drug Levels Associated with Pseudohyperaldosteronism

BackgroundPosaconazole is an extended-spectrum triazole used in the treatment and prophylaxis of many fungal diseases. There have been case reports of posaconazole-induced pseudohyperaldosteronism; however, its occurrence and association with serum posaconazole drug levels need further investigation.MethodsIn this single-center retrospective observational study, we examined the occurrence of posaconazole-induced pseudohyperaldosteronism (PIPH), diagnosed either clinically or via laboratory abnormalities, and evaluated differences in serum posaconazole concentration and clinical characteristics between those with and without this syndrome.ResultsSixty-nine patients receiving posaconazole were included; of whom, 16 (23.2%) met the definition of PIPH. Patients with PIPH were significantly older (61.1 vs. 44.7 years, P = 0.007), more frequently had hypertension prior to starting posaconazole (68.8% vs. 32.1%, P = 0.009), and were more frequently prescribed posaconazole for active treatment instead of prophylaxis compared with patients without PIPH (62.5% vs. 24.5%, P = 0.005). Patients with PIPH had a significantly higher median serum posaconazole level than those without PIPH (3.0 vs. 1.2 µg/mL, P = 0.0001). There was a positive correlation between serum posaconazole level and change in systolic blood pressure (r = 0.37, P = 0.01), a negative correlation between serum posaconazole level and change in serum potassium (r = −0.39, P = 0.006), and a positive correlation between serum posaconazole level and serum 11-deoxycortisol (r = 0.69, P < 0.0001).ConclusionPosaconazole is associated with secondary hypertension and hypokalemia, consistent with pseudohyperaldosteronism, and development is associated with higher serum posaconazole concentrations, older age, and baseline hypertension. Management may include dose reduction, the addition of an aldosterone antagonist, or an alternative triazole agent. Disclosures All authors: No reported disclosures.

Posaconazole Serum Drug Levels Associated With Pseudohyperaldosteronism.

Posaconazole tablets are well tolerated and efficacious in the prophylaxis and treatment of aspergillosis, mucormycosis, and other invasive fungal infections. There have been case reports of posaconazole-induced pseudohyperaldosteronism (PIPH); however, its occurrence and association with serum posaconazole drug levels have not previously been investigated. In this single-center, retrospective, observational study, we examined the occurrence of PIPH in outpatients newly starting posaconazole and evaluated differences in serum posaconazole concentrations and clinical characteristics between those with and without this syndrome. Sixty-nine patients receiving posaconazole were included, of whom 16 (23.2%) met the definition of PIPH. Patients with PIPH were significantly older (61.1 vs 44.7 years, P = .007) and more frequently had hypertension prior to starting posaconazole (68.8% vs 32.1%, P = .009). Patients with PIPH had a significantly higher median serum posaconazole level than those without PIPH (3.0 vs 1.2 µg/mL, P ≤ .0001). There was a positive correlation between serum posaconazole levels and changes in systolic blood pressure (r = .37, P = .01), a negative correlation between serum posaconazole levels and changes in serum potassium (r = -.39, P = .006), and a positive correlation between serum posaconazole levels and serum 11-deoxycortisol (r = .69, P < .0001). Posaconazole is associated with secondary hypertension and hypokalemia, consistent with pseudohyperaldosteronism, and development is associated with higher serum posaconazole concentrations, older age, and baseline hypertension.

The impact of azole antifungal drugs on imatinib metabolism in human liver microsomes

1. Imatinib is widely used for the treatment of hematologic malignancies. It is common that imatinib is clinically co-prescribed with azole antifungal agents since these patients are more prone to invasive antifungal infection. The present study was to investigate the effects of azole antifungal drugs, including ketoconazole, fluconazole, voriconazole, itraconazole and posaconazole on imatinib metabolism.2. The main metabolites, 1-OH midazolam and N-desmethyl imatinib, were determined in the absence and in the presence of various levels of ketoconazole, fluconazole, voriconazole, itraconazole and posaconazole. The relevant assay was also performed to screen mechanism-based inhibitors (MBI).3. The inhibition ability of 1-OH midazolam formation from midazolam based on IC50 values was ketoconazole (0.09 µM)>itraconazole (0.31 µM)> posaconazole (0.68 µM)>voriconazole (2.10 µM) > fluconazole (8.90 µM). Similarly, the rank order of inhibitory effects on formation of N-desmethyl imatinib from imatinib was ketoconazole (4.58 µM)>itraconazole (17.45 µM)> posaconazole (31.02 µM)> voriconazole (367.9 µM) >fluconazole (1.11 mM). Posaconazole and itraconazole displayed evidence of MBI. Additionally, imatinib was also shown as a MBI of CYP3A with IC50 value of 5.40 µM against the midazolam.4. The significant difference in IC50 values of midazolam and imatinib inhibited by azole antifungal agents was observed. The role of CYP2C8 in imatinib metabolism and imatinib autoinhibits CYP3A activity may explain this difference. Our findings suggest that the azole antifungal agents might have limited impacts on imatinib exposure by CYP3A activity.

Posaconazole therapy in children with cystic fibrosis and Aspergillus-related lung disease.

There is emerging evidence for the role of posaconazole in the management of Aspergillus-related cystic fibrosis (CF) lung disease. The tolerability and efficacy of posaconazole in paediatric CF is not well established. We report a prospective study over a fifty-three month period evaluating the safety, tolerability, and efficacy of posaconazole in pediatric CF. Fourteen children (seven males, median age 13 years, range 3-17 years) received a total of twenty-three courses of posaconazole (13 oral suspension and 10 tablet formulation). Of these patient episodes, nine received posaconazole for emerging or active allergic bronchopulmonary aspergillosis (ABPA) and two required a combination of posaconazole and systemic corticosteroids for difficult-to-treat ABPA. A subgroup of patients (n = 12) with persistent isolates of Aspergillus fumigatus, in the absence of serological markers of ABPA, received posaconazole monotherapy for pulmonary exacerbations not responding to conventional broad-spectrum antibiotic treatment. Posaconazole levels, full blood count, electrolytes, and liver function were monitored on day 7 of treatment and then monthly. Posaconazole was well tolerated in all but three patients. Therapeutic plasma levels >1mg/l were achieved in all receiving the tablet formulation in comparison to 60% on the liquid preparation. There was a modest but significant improvement in FEV1 (% predicted) demonstrated for the cohort as a whole (p = 0.015) following posaconazole therapy. Posaconazole is well tolerated in children as young as six years old, improvements in lung function are observed, and therapeutic plasma levels are readily achieved in patients taking the tablet formulation and in adherent patients taking the liquid formulation.

Posaconazole for the treatment of allergic bronchopulmonary aspergillosis in patients with cystic fibrosis.

Allergic bronchopulmonary aspergillosis (ABPA) can accelerate lung function decline in patients with cystic fibrosis (CF). Antifungal medication can be used in addition to systemic corticosteroid treatment. We evaluated Aspergillus-specific IgE and the use of therapeutic drug monitoring of triazoles in a retrospective analysis of 32 patients. There was a significant reduction in Aspergillus IgE with posaconazole but not with other triazoles (P = 0.026). Aspergillus IgE levels were inversely correlated with the therapeutic drug level of posaconazole. These data suggest that posaconazole is better than comparator azoles at decreasing serological response to Aspergillus and that this response was better with therapeutic levels of posaconazole.

Therapeutic drug monitoring and adverse events of delayed-release posaconazole tablets in patients with chronic pulmonary aspergillosis.

Posaconazole delayed-release tablets offer better bioavailability than the liquid suspension, but no post-marketing data are available in immunocompetent hosts such as those with chronic pulmonary aspergillosis (CPA). To explore the pharmacokinetics and adverse event (AE) profile of posaconazole tablets in patients with CPA. Patients started on posaconazole tablets at the National Aspergillosis Centre (NAC), Manchester, UK between February 2014 and October 2015 were identified from the NAC database and analysed retrospectively. The medical records were reviewed for factors that could affect posaconazole serum levels and the development of AEs. Seventy-two patients were included; 50 (69%) were male and the mean age was 48.5 ± 12 years. Therapeutic levels (≥1 mg/L) were achieved in 90% of cases on 200 mg versus 90% of cases on 300 mg daily (P = not significant). Based on multivariate analysis, female sex (P = 0.041), a 100 mg daily dose (P < 0.001), asthma (P = 0.01) and bronchiectasis (P = 0.001) were associated with subtherapeutic levels. Forty-nine (68%) patients developed AEs, mainly fatigue (37%), dyspnoea (18%) and nausea (12%). AEs were present on 115/196 (59%) occasions on 300 mg/day and on 45/115 (39%) occasions on 200 mg/day (P < 0.01). The mean level was 1.81 ± 0.96 mg/L for patients reporting no AEs and 1.90 ± 1.11 mg/L for those reporting AEs (P = not significant). Factors associated with AEs of grade ≥2 were a daily dose of 300 versus 200 mg (P = 0.001) and asthma (P = 0.008). A lower-than-recommended posaconazole tablet dose achieved therapeutic levels in most patients and was better tolerated. Males were more likely to achieve a therapeutic level. Underlying conditions affected the degree and frequency of AEs.

A Prospective Real-World Study of the Impact of an Antifungal Stewardship Program in a Tertiary Respiratory-Medicine Setting.

There has been an increase in fungal infections in patients with chronic lung disease over the past decades, which is associated with rapidly increasing costs to health care systems. An antifungal stewardship team was introduced to a tertiary cardiopulmonary hospital, consisting of a medical mycologist and pharmacy support providing weekly stewardship ward rounds, twice-monthly multidisciplinary team meetings, and a dedicated weekly outpatient clinic. A database was set up to record the activity of the stewardship team. During the first 18 months of implementation, the antifungal stewardship team had reviewed 178 patients, with 285 recommendations made to inpatients, and 287 outpatient visits. The commonest diagnoses treated were allergic bronchopulmonary aspergillosis and chronic pulmonary aspergillosis. Cystic fibrosis was the largest patient group treated, followed by asthma and interstitial lung disease. There was a significant sustained reduction in monthly antifungal expenditure (P = 0.005) by £130,000 per month. There was also a significant reduction in antifungal use, measured as the defined daily dose/100 bed days (P = 0.017). There were no significant changes in expenditure on diagnostic tests. There has been a trend toward more patients having therapeutic levels of voriconazole (P = 0.086) and a significant increase in therapeutic levels of posaconazole (P < 0.0001). This study shows that an effective antifungal stewardship program can significantly reduce expenditure in a specialist respiratory service.

552 - Comparison of Therapeutic Drug Levels of Adult and Pediatric Patients Undergoing Treatment for Fungal Diseases

Background: The mortality of invasive fungal infections is significant, indicating the critical need for appropriate treatment and dosing of anti-fungal drugs. Variable absorption and pharmacokinetics of triazole antifungal drugs (e.g. posaconazole and voriconazole) create a challenge for physicians to consistently achieve blood levels in the therapeutic range, particularly in patients suffering from comorbidities. The use of therapeutic drug monitoring (TDM) is critical for ensuring efficacy of voriconazole (VOR) and posaconazole (POS) treatment. Dosing in pediatric patients can prove more difficult because there have been fewer studies in these patient populations. Methods: Drug levels of POS and VOR were determined by reverse phase LC MS/MS on plasma or serum samples submitted for testing. Results were de-identified and reviewed to determine whether results fell within the therapeutic range for effective anti-fungal treatment. A large sample set (POS approximately 2500 samples and VOR approximately 5500 samples) was included to reduce the chance of sample size variability. Pediatric samples were defined as those coming from patients 17 years and younger. Results: For POS, in pediatric patients, 7.5% of samples tested had drug levels below the limit of detection of the assay (.1 mcg/mL) compared to 4% in adults; and an additional 19% of samples in pediatric and 13% in adults tested had detectable levels that were below the suggested therapeutic level of .7 mcg/mL. For VOR, the percentage of samples tested with results either above or below the therapeutic window was even higher: 6.7% of adult samples and 10.8% of pediatric samples tested had drug levels below the limit of detection of the assay (.1 mcg/mL), and an additional 21.3% of adult samples and 39.2% of pediatric sample had detectable levels that were below the suggested therapeutic range of 1.0-5.5 mcg/mL. Additionally, 13.4% of adult samples and 7.7% of pediatric samples tested had levels that were above the therapeutic range. Conclusions: From these data it is clear that an alarmingly high number of both adult and pediatric patient samples tested (24% of adult and 46% of pediatric) have antifungal drug levels below the recommended therapeutic levels. These data indicate the criticality of monitoring antifungal drug levels because of the high frequency of sub-therapeutic concentrations due to variations in metabolism, absorption or even patient compliance. Moreover, 7% of VOR results demonstrated levels above the recommended therapeutic levels, putting these patients at risk for toxicity.

Simultaneous determination of voriconazole, posaconazole, itraconazole and hydroxy-itraconazole in human plasma using LCMS/MS

IntroductionInvasive fungal infections are an increasing cause of mortality and morbidity in high risk patient populations such as those on immunosuppressive therapy. Triazole antifungals are recommended for the prevention and treatment of such infections.The aim of this study was to develop and validate a simple, sensitive and robust LCMS/MS method for the simultaneous analysis in human plasma of three frequently used antifungal drugs: voriconazole, posaconazole, and itraconazole. MethodsPrecipitation reagent, containing deuterated internal standards, is added to 50μL of plasma. The vials are vortexed before centrifugation. The organic supernatant is transferred to a polypropylene vial and 1μL is injected into the Waters Acquity® Ultra Performance Liquid Chromatography system coupled with a Waters Acquity® TQ Detector system. Chromatographic separation is achieved on a BEH C18 column using gradient elution with mobile phases consisting of 2mM ammonium acetate with 0.1% formic acid in water and methanol. Run time is <5min between injections. ResultsThe evaluation of the LCMS/MS triazole method showed good precision (intra-assay CVs<6.7%, inter-assay CVs<8.3%).The lower limit of quantitation for all antifungal triazoles tested was 0.10mg/L.Passing Bablok comparisons of voriconazole (n=50) and posaconazole (n=50) showed good correlation with the current HPLC method (Voriconazole LCMS=0.94(HPLC)+0.03, r2=0.99; Posaconazole LCMS=1.18(HPLC)−0.04, r2=0.95).Passing Bablok comparisons of itraconazole and hydroxy-itraconazole (n=18) showed good agreement with an external referral laboratory's antifungal LCMS/MS method (Itraconazole LCMS=1.00(referral lab)+0.01, r2=0.99; Hydroxy-Itraconazole LCMS=1.05(referral lab)+0.04, r2=0.99).External quality assurance samples for posaconazole and voriconazole (n=12, UK NEQAS Antifungal Pilot Panel) were assayed ‘blind’ and results were in good agreement with consensus mean values (both r2=0.99). ConclusionThe rapid pre-analytical sample preparation procedure, short chromatographic time, limit of quantitation and linear range make this LCMS/MS method suitable for determination of plasma voriconazole, posaconazole, itraconazole and hydroxy-itraconazole levels in a high throughput laboratory.

Alternative approaches to the therapeutic drug monitoring of prophylactic posaconazole in haematology patients

The intention of the study was to assess whether a unique daily specimen is adequate for prophylactic posaconazole TDM in haematology patients and if bioassay and HPLC produce similar results and could be equally used in clinical setting. Serum specimens from thirty haematology patients were collected at the end of the first and second week of treatment, just before the morning dose, 2 and 6 to 8hours afterwards. Levels were measured by bioassay in 157 specimens and additionally by HPLC in 51 of them. Bioassay levels were correlated inter and intra daily, with no statistical difference between them, irrespective of the timing. The same was true for HPLC measurements. There was no statistical difference between bioassay (median: 1.60mg/L, interquartile range: 0.60-2.30) and HPLC levels (median: 1.16mg/L, interquartile range: 0.56-1.72), while they were significantly correlated. In clinically stable haematology patients, a random specimen on any day after steady state serum concentrations have been achieved is probably adequate in order to monitor posaconazole levels. In the case of monotherapy, a bioassay is an acceptable alternative to HPLC.

Therapeutic Drug Monitoring (TDM) of Suspension (SUS), Extended-Release (ER), and Intravenous (IV) Posaconazole (POS) at a Large Transplant Center

BackgroundData on ER and IV POS among organ transplant recipients (OTRs) are limited, and the role of TDM is unclear.MethodsRetrospective study of patients (pt) receiving any formulation of POS who had serum troughs checked. Therapeutic was defined as 3 1 mcg/mL.ResultsWe analyzed 88 pt and 340 levels (SUS: 88, ER: 197, IV: 55). Eighty-five pt were OTRs (97%), 73 were lung transplant recipients (LT) (83%), 17 had cystic fibrosis (CF) (19%). POS was used for treatment (70%) (probable aspergillosis (38%), possible aspergillosis (10%), mucormycosis (16%), other mycoses (6%)), prophylaxis (19%), and pre-emptive therapy (14%). POS was given for intolerance of or contraindication to other azoles (47%), salvage therapy (10%), resistance (19%), and failure to achieve therapeutic levels with other azoles (6%). Serum concentration/dose ratios were lower with SUS vs. ER/IV (P < 0.0001) but were similar in ER/IV groups (P = 0.51) (Figure). There was no difference in serum levels between pt receiving ER vs. IV POS at 300 mg once daily (median 1.2 vs. 1.3 mcg/mL, therapeutic 70% vs. 73%, P = 0.57 and >0.99, respectively). 3 pt had levels £ 0.2 mcg/mL on 300 mg ER: 2 had CF and had undergone LT (0.2 and 0 mcg/mL) and 1 had short-gut syndrome (0.1 mcg/mL). Sixty-six percent and 67 % of pt receiving ER or IV POS (300 mg once daily) achieved initial therapeutic levels, respectively; of these, 87% and 83% had median therapeutic follow-up levels, respectively. Serial levels were available for 7 pt whose dose was increased from 300 to 400 mg ER once daily for subtherapeutic levels. 4/7 pt achieved therapeutic levels on 400 vs. 0/7 on 300 mg ER once daily (P = 0.069). Metoclopramide use and CF were associated with subtherapeutic vs. therapeutic levels (25% vs. 4% and 37% vs. 13%, respectively, P = < 0.05). When pt with CF were excluded, neither age nor body mass index were associated with POS levels. CF pt had lower levels than non-CF pt on a dose of 300 mg ER once daily (median 0.8 vs. 1.3 mcg/mL, P = 0.018).ConclusionTherapeutic levels are more reliably achieved with ER & IV POS compared with SUS POS. Serial TDM is unnecessary for most, but is recommended for pt with CF or those on metoclopramide. Dose increases may effectively increase levels. Novel dosing strategies are needed for CF.Disclosures R. K. Shields, Astellas: Received research funding, Research support. Merck: Received research funding, Research support. C. J. Clancy, Merck: Received research funding, Research support. Astellas: Received research funding, Research support. Cidara: Received research funding, Research support. Astellas: Scientific Advisor, Advisory board. Merck: Scientific Advisor, Advisory board. Cidara: Scientific Advisor, Advisory board. Medicines Company: Scientific Advisor, Advisory board.

Posaconazole-Induced Hypertension and Hypokalemia: Mechanistic Evaluation

Background Recent studies have shown the new posaconazole delayed-release tablets have superior bioavailability compared with the liquid suspension formulation. As higher serum posaconazole concentrations have been associated with improved clinical responses, this formulation has been a welcome addition to available treatment options. However, higher serum and tissue levels are likely to reveal previously undescribed toxicity as adverse events attributed to “off-target” effects are observed.Methods We prospectively identified two patients with new onset hypertension, hypokalemia, and alkalosis after starting posaconazole tablets. Patient vital signs and laboratory values were within normal limits prior to starting posaconazole; however, following over 30 days of therapy both patients became newly hypertensive (mean systolic BP increase 59 mmHg). Serum posaconazole levels were 4.3–4.6 μg/ml. Complete suppression of renin and aldosterone, with increased 11-deoxycortisol, estradiol levels, and cortisol/cortisone ratios were observed in both patients. The TTKG in both patients was inappropriately elevated.ResultsPosaconazole-induced disruption of the steroid biosynthesis pathway in patients has not previously been described, but has been suggested by in vitro studies. Our patients’ laboratory results show clinically significant inhibition of 11β-hydroxysteroid dehydrogenase enzyme type 2 isoform (11β-HSD2) as evidenced by: the elevated 11-deoxycortisol (with subsequent suppression of renin and aldosterone), the highly elevated cortisol/cortisone ratio, and the inappropriately elevated TTKG in the setting of hypokalemia. The normal deoxycorticosterone confirms normal function of 11β-hydroxylase and the observed effects in our patients are thus downstream from this enzyme.Conclusion Our findings support in vitro predictions and highlight the clinical sequelae of posaconazole-mediated inhibition of 11β-HSD2. Additional studies are necessary to determine the frequency of posaconazole induced apparent mineralocorticoid excess syndrome and whether other azole antifungals can be associated with this phenomenon.Disclosures All authors: No reported disclosures.

Voriconazole and posaconazole therapeutic drug monitoring: a retrospective study

BackgroundTherapeutic drug monitoring (TDM) aims to minimize the clinical impact of posaconazole and voriconazole pharmacokinetic variability. However, its benefits on clinical outcomes are still being defined. Additionally, TDM data are limited for posaconazole IV and delayed-release tablet formulations among specific patient populations, including critically ill. The aim of this study was to determine the percentage of therapeutic posaconazole and voriconazole drug levels across all formulations in a real-world clinical setting and elucidate factors affecting attainment of target concentrations.MethodsThis study was a retrospective cohort study conducted at the University of Colorado Hospital between September 2006 and June 2015 that evaluated patients who received posaconazole or voriconazole TDM as part of routine care.ResultsVoriconazole (n = 250) and posaconazole (n = 100) levels were analyzed from 151 patients. Of these, 54% of voriconazole and 69% of posaconazole levels were therapeutic. For posaconazole, 14/38 (37%), 28/29 (97%) and 27/33 (82%) levels were therapeutic for the oral suspension, IV, and delayed-release tablet, respectively. Intravenous and delayed-release tablet posaconazole were 20 fold (p < 0.01) and sevenfold (p = 0.002) more likely than the oral suspension to achieve a therapeutic level. Subsequent levels were more likely to be therapeutic after dose adjustments (OR 3.31; 95% CI 1.3–8.6; p = 0.02), regardless of timing of initial non-therapeutic level. In a multivariable logistic regression analysis, no characteristics were independently predictive of therapeutic voriconazole levels and only absence of H2RA/PPI use was independently predictive of therapeutic posaconazole levels. There was no correlation between survival and therapeutic drug levels for either voriconazole (p = 0.67) or posaconazole (p = 0.50).ConclusionsA high percentage of drug levels did not achieve TDM targets for voriconazole and posaconazole oral suspension, supporting the need for routine TDM for those formulations. The utility of TDM for the IV and delayed-release tablet formulations of posaconazole is less apparent.

Retrospective analysis of goal drug level attainment of posaconazole for invasive fungal infection prophylaxis in patients with acute myeloid leukemia pre- and post-switch to tablet formulation.

Posaconazole is approved for invasive fungal infection prophylaxis in patients with hematologic malignancies. Posaconazole suspension is plagued by poor oral absorption and dietary requirements that are difficult for patients to meet. The delayed-release tablet formulation of posaconazole may be taken without regards to meals and has significantly better oral absorption than posaconazole suspension. We sought to determine if a switch to posaconazole tablets improved steady-state drug level attainment for invasive fungal infection prophylaxis in patients with acute myeloid leukemia. All adult inpatients with acute myeloid leukemia undergoing chemotherapy, who received posaconazole for invasive fungal infection prophylaxis between 2012 and 2015, were included. The primary outcome was proportion of patients with first posaconazole level greater than 700 ng/mL. Secondary outcomes included proportion of patients with first posaconazole level greater than 1000 ng/mL, invasive fungal infection within 100 days, and adverse drug events. Forty patients received posaconazole tablets and 34 patients received suspension. Posaconazole levels were significantly higher at first measurement in patients receiving tablet than suspension (1296 ng/mL vs. 788 ng/mL, p < 0.01). Thirty-seven patients receiving tablets had a serum drug level greater than 700 ng/mL on first measurement versus 18 receiving suspension (p < 0.01). Patients receiving tablets were also more likely to have a serum drug level over 1000 ng/mL on first measurement (26 vs. 11, p < 0.01). Rates of invasive fungal infection and adverse events were not statistically different. Patients receiving posaconazole tablets attained significantly higher serum drug levels than those receiving suspension.

Real-Life Assessment of the Safety and Effectiveness of the New Tablet and Intravenous Formulations of Posaconazole in the Prophylaxis of Invasive Fungal Infections via Analysis of 343 Courses.

Posaconazole is the preferred mold-active azole for prophylaxis against invasive fungal infections (IFIs) in patients with hematological malignancy. Delayed-release tablet and intravenous formulations of posaconazole have recently become available, but clinical data are limited. We sought to examine the real-world pharmacokinetics and prophylactic effectiveness of the new formulations of posaconazole given as prophylaxis for patients with hematological malignancy. A retrospective cohort of all consecutive adult inpatients with hematological malignancy who received ≥3 days of tablet or intravenous posaconazole therapy for primary IFI prophylaxis at the M. D. Anderson Cancer Center between 1 December 2013 and 31 December 2015 was established. Clinical information was collected and correlated with low posaconazole serum levels (<700 ng/ml). Rates of IFIs and safety events were assessed. A total of 1,321 courses of posaconazole were administered at the M. D. Anderson Cancer Center during the study period, of which 343 courses were assessed for prophylactic safety and effectiveness. Seventy-nine patients (23%) had posaconazole serum level measurements available for interpretation. Acute myeloid leukemia was the primary malignancy (62%), with 20% of all patients having previously received a stem cell transplant. The median posaconazole level was 1,380 ng/ml (interquartile range, 864 to 1,860 ng/ml). Low posaconazole levels (<700 ng/ml) were observed for 14 patients (18%). Proven or probable breakthrough IFIs occurred in 8 patients (2%); posaconazole therapeutic drug monitoring (TDM) was performed for 6 of those patients, all with levels above 700 ng/ml. Overall, 19% of patients experienced grade 3 or 4 liver injury, manifesting primarily as hyperbilirubinemia and being correlated with serum levels of >1,830 ng/ml. Although hepatotoxicity in a small percentage of patients is of concern, posaconazole tablets appeared to be generally safe and effective. As all breakthrough IFIs for which TDM was performed occurred in patients with levels of >700 ng/ml, and a posaconazole level of >1,830 ng/ml was correlated with grade 3 or 4 liver toxicity, further studies are needed to assess the role of TDM.