Population Pharmacokinetics of Intravenous Isavuconazole in Solid-Organ Transplant Recipients

Isavuconazole Versus Voriconazole as the First-line Therapy for Solid Organ Transplant Recipients With Invasive Aspergillosis: Comparative Analysis of 2 Multicenter Cohort Studies

BACKGROUND

Isavuconazole (ISA) and voriconazole (VORI) are recommended as the first-line treatment for invasive aspergillosis (IA). Despite theoretical advantages of ISA, both triazole agents have not been compared in solid organ transplant recipients.

METHODS

We performed a post hoc analysis of 2 retrospective multicenter cohorts of solid organ transplant recipients with invasive fungal disease (the SOTIS [Solid Organ Transplantation and ISavuconazole] and DiasperSOT [DIagnosis of ASPERgillosis in Solid Organ Transplantation] studies). We selected adult patients with proven/probable IA that were treated for ≥48 h with ISA (n = 57) or VORI (n = 77) as first-line therapy, either in monotherapy or combination regimen. The primary outcome was the rate of clinical response at 12 wk from the initiation of therapy. Secondary outcomes comprised 12-wk all-cause and IA-attributable mortality and the rates of treatment-emergent adverse events and premature treatment discontinuation.

RESULTS

Both groups were comparable in their demographics and major clinical and treatment-related variables. There were no differences in the rate of 12-wk clinical response between the ISA and VORI groups (59.6% versus 59.7%, respectively; odds ratio [OR], 0.99; 95% confidence interval [CI], 0.49-2.00). This result was confirmed after propensity score adjustment (OR, 0.81; 95% CI, 0.32-2.05) and matching (OR, 0.79; 95% CI, 0.31-2.04). All-cause and IA-attributable mortality were also similar. Patients in the ISA group were less likely to experience treatment-emergent adverse events (17.5% versus 37.7%; P = 0.011) and premature treatment discontinuation (8.8% versus 23.4%; P = 0.027).

CONCLUSIONS

Front-line treatment with ISA for posttransplant IA led to similar clinical outcomes than VORI, with better tolerability and higher treatment completion.

Early attainment of isavuconazole target concentration using an increased loading dose in critically ill patients with extracorporeal membrane oxygenation

BACKGROUND

In critically ill patients with extracorporeal membrane oxygenation (ECMO) attainment of target concentration of isavuconazole is delayed using the routine loading dose.

OBJECTIVES

We investigated the influence of increasing the first loading dose of isavuconazole on plasma concentrations in critically ill patients treated with ECMO.

METHODS

Fifteen patients were included in this study, and isavuconazole concentrations were measured at several timepoints starting 2 h after the first isavuconazole dose up to 168 h. By interim analysis of isavuconazole concentrations and meticulous screening for adverse events, the first loading dose was stepwise increased from 200 to 300 mg, and finally to 400 mg.

RESULTS

Seven of 15 patients (47%) received standard isavuconazole loading dosage with 200 mg as the first dose, 3/15 (20%) received 300 mg, and 5/15 (33%) received 400 mg isavuconazole as the first dose, followed by subsequent standard dosing in all patients. In patients receiving 400 mg as the first dose all isavuconazole concentrations were significantly higher at timepoints up to the first 24 h, resulting in higher proportions of isavuconazole concentrations ≥1 mg/L compared with patients with other loading dosages. In timepoints ≥24 h after isavuconazole initiation all patient groups reached comparable plasma concentrations, regardless of the first loading dose regimen. We did not observe concentrations above ≥5 mg/L or any adverse events related to isavuconazole administration.

CONCLUSIONS

In critically ill patients with ECMO the 400 mg loading dose of isavuconazole resulted in immediate median isavuconazole plasma concentrations ≥1 mg/L and remained constant above this threshold after the first loading dose.

Clinical and demographic factors affecting trough levels of isavuconazole in critically ill patients with or without COVID-19

BACKGROUND

The broad-spectrum antifungal isavuconazole is administered to treat invasive aspergillosis and mucormycosis.

OBJECTIVES

Isavuconazole plasma concentrations in critically ill ICU patients with or without COVID-19 and invasive fungal infection were determined, and factors for sub-therapeutic drug levels (<1 μg/mL) were evaluated.

PATIENTS AND METHODS

Isavuconazole plasma levels were measured as part of therapeutic drug monitoring (TDM) in ICUs of a tertiary hospital. Concentrations determined 20-28 h after previous dosing were defined as trough (Cmin ) levels. A total of 160 Cmin levels from 62 patients with invasive fungal infections were analysed, 30 of which suffering from COVID-19. Patient characteristics included into univariable and multivariable analyses were gender, age, COVID-19 status, body mass index (BMI), sepsis-related organ failure (SOFA) score, renal replacement therapy (RRT) and extracorporeal membrane oxygenation (ECMO) requirement.

RESULTS

The mean Cmin of isavuconazole in all patients was 1.64 μg/mL (interquartile range 0.83-2.24 μg/mL, total range 0.24-5.67 μg/mL). In total, 34.4% of the Cmin values (corresponding to 46.8% of patients) were below a threshold concentration of 1 μg/mL. Drug concentrations between patients with or without COVID-19 did not differ (p = .43). In contrast, levels were significantly lower in patients with female sex (p = .0007), age ≤ 65 years (p = .002), BMI > 25 (p = .006), SOFA score > 12 (p = .026), RRT (p = .017) and ECMO requirement (p = .001).

CONCLUSIONS

Isavuconazole plasma levels can be negatively affected by patients' risk factors, supportive renal replacement and ECMO therapy. Future prospective studies analysing the relevance of isavuconazole drug levels in ICU patient outcome are urgently needed.

PK/PD modeling and simulation of the in vitro activity of the combinations of isavuconazole with echinocandins against Candida auris

In vitro combination of echinocandins and isavuconazole against the emerging species Candida auris is mainly synergistic. However, this combination has not been evaluated in clinical settings. A pharmacokinetic/pharmacodynamic modeling and simulation approach based on in vitro data may be helpful to further study the therapeutic potential of these combinations. Therefore, the aims of this study were to characterize the time course of growth and killing of C. auris in response to the combination of the three approved echinocandins and isavuconazole using a semimechanistic model and to perform model-based simulations in order to predict the in vivo response to combination therapy. In vitro static time-kill curve data for isavuconazole and echinocandins combinations against six blood isolates of C. auris were best modeled considering the total killing of the fungal population as dependent on the additive effects of both drugs. Once assessed, the predictive performance of the model using simulations of different dosing and fungal susceptibility scenarios were conducted. Model-based simulations revealed that none of the combinations at standard or higher dosages would be effective against the studied isolates of C. auris and it was predicted that the combinations of isavuconazole with anidulafungin or caspofungin would be effective for minimum inhibitory concentrations up to 0.03 and 0.06 mg/L respectively, whereas the combination with micafungin would lead to treatment failure. The current approach highlights the importance of bridging the in vitro results to the clinic.

A Hybrid Algorithm Combining Population Pharmacokinetic and Machine Learning for Isavuconazole Exposure Prediction

OBJECTIVES

Maximum a posteriori Bayesian estimation (MAP-BE) based on a limited sampling strategy and a population pharmacokinetic (POPPK) model is used to estimate individual pharmacokinetic parameters. Recently, we proposed a methodology that combined population pharmacokinetic and machine learning (ML) to decrease the bias and imprecision in individual iohexol clearance prediction. The aim of this study was to confirm the previous results by developing a hybrid algorithm combining POPPK, MAP-BE and ML that accurately predicts isavuconazole clearance.

METHODS

A total of 1727 isavuconazole rich PK profiles were simulated using a POPPK model from the literature, and MAP-BE was used to estimate the clearance based on: (i) the full PK profiles (refCL); and (ii) C24h only (C24h-CL). Xgboost was trained to correct the error between refCL and C24h-CL in the training dataset (75%). C24h-CL as well as ML-corrected C24h-CL were evaluated in a testing dataset (25%) and then in a set of PK profiles simulated using another published POPPK model.

RESULTS

A strong decrease in mean predictive error (MPE%), imprecision (RMSE%) and the number of profiles outside ± 20% MPE% (n-out20%) was observed with the hybrid algorithm (decreased in MPE% by 95.8% and 85.6%; RMSE% by 69.5% and 69.0%; n-out20% by 97.4% and 100% in the training and testing sets, respectively. In the external validation set, the hybrid algorithm decreased MPE% by 96%, RMSE% by 68% and n-out20% by 100%.

CONCLUSION

The hybrid model proposed significantly improved isavuconazole AUC estimation over MAP-BE based on the sole C24h and may improve dose adjustment.

Isavuconazole for the Treatment of Invasive Mold Disease in Solid Organ Transplant Recipients: A Multicenter Study on Efficacy and Safety in Real-life Clinical Practice

BACKGROUND

Isavuconazole has theoretical advantages over other mold-active triazoles for the treatment of invasive aspergillosis and mucormycosis after solid organ transplantation (SOT). The available clinical experience, nevertheless, is scarce.

METHODS

We performed a retrospective study including all adult SOT recipients with proven or probable invasive mold disease (IMD) that received isavuconazole for ≥24 h as first-line or salvage therapy at 10 Spanish centers between September 2017 and November 2021. The primary efficacy outcome was clinical response (complete or partial resolution of attributable symptoms and findings) by weeks 6 and 12. Safety outcomes included the rates of treatment-emergent adverse events and premature isavuconazole discontinuation.

RESULTS

We included 81 SOT recipients that received isavuconazole for a median of 58.0 days because of invasive aspergillosis (n = 71) or mucormycosis (n = 10). Isavuconazole was used as first-line (72.8%) or salvage therapy due because of previous treatment-emergent toxicity (11.1%) or refractory IMD (7.4%). Combination therapy was common (37.0%), mainly with an echinocandin or liposomal amphotericin B. Clinical response by weeks 6 and 12 was achieved in 53.1% and 54.3% of patients, respectively, and was more likely when isavuconazole was administered as first-line single-agent therapy. At least 1 treatment-emergent adverse event occurred in 17.3% of patients, and 6.2% required premature discontinuation. Daily tacrolimus dose was reduced in two-thirds of patients by a median of 50.0%, although tacrolimus levels remained stable throughout the first month of therapy.

CONCLUSIONS

Isavuconazole is a safe therapeutic option for IMD in SOT recipients, with efficacy comparable to other patient groups.

Isavuconazole Therapeutic Drug Monitoring in critically ill ICU patients - a monocentric retrospective analysis

BACKGROUND

The broad-spectrum triazole isavuconazole is used for the treatment of invasive aspergillosis and mucormycosis. Data regarding human plasma concentrations in clinical routine of the drug are rare.

OBJECTIVES

Plasma concentrations of isavuconazole were determined in critically ill ICU patients while considering different patients' characteristics.

METHODS

Retrospective analysis of isavuconazole plasma concentrations were obtained as part of routine therapeutic drug monitoring (TDM) of ICU patients with invasive aspergillosis or other fungal infections treated with isavuconazole. Plasma levels 0-4h after last dosing were defined as peak levels (C_max ), those 20-28h after last dosing as trough levels (C_min ).

RESULTS

Overall, 223 isavuconazole levels of 41 patients were analysed, divided into 141 peak levels and 82 trough levels. The overall median C_max was 2.36 μg/mL (mean 2.43 μg/mL, range 0.41 - 7.79 μg/mL) and the overall median C_min was 1.74 μg/mL (mean 1.77 μg/mL, range 0.24 - 4.96 μg/mL). In total, 31.7% of the C_min values of the total cohort were below the plasma target concentrations of 1 μg/mL, defined as EUCAST antifungal clinical breakpoint for Aspergillus fumigatus. Both peak and trough plasma levels of isavuconazole were significantly lower among patients with a body-mass-index (BMI) ≥ 25. In addition, a significant correlation was observed between isavuconazole trough levels and sepsis-related organ failure assessment (SOFA) score.

CONCLUSIONS

This study shows that isavuconazole plasma concentrations vary in critical ill ICU patients. Significantly lower isavuconazole levels were associated with elevated BMI and higher SOFA score indicating a need of isavuconazole TDM in this specific patient population.

"De-Shrinking" EBEs: The Solution for Bayesian Therapeutic Drug Monitoring

BACKGROUND

Therapeutic drug monitoring (TDM) aims at individualising a dosage regimen and is increasingly being performed by estimating individual pharmacokinetic parameters via empirical Bayes estimates (EBEs). However, EBEs suffer from shrinkage that makes them biased. This bias is a weakness for TDM and probably a barrier to the acceptance of drug dosage adjustments by prescribers.

OBJECTIVE

The aim of this article is to propose a methodology that allows a correction of EBE shrinkage and an improvement in their precision.

METHODS

As EBEs are defined, they can be seen as a special case of ridge estimators depending on a parameter usually denoted λ. After a bias correction depending on λ, we chose λ so that the individual pharmacokinetic estimations have minimal imprecision. Our estimate is by construction always better than EBE with respect to bias (i.e. shrinkage) and precision.

RESULTS

We illustrate the performance of this approach with two different drugs: iohexol and isavuconazole. Depending on the patient's actual pharmacokinetic parameter values, the improvement given by our approach ranged from 0 to 100%.

CONCLUSION

This innovative methodology is promising since, to the best of our knowledge, no other individual shrinkage correction has been proposed.

Antifungal Drugs TDM: Trends and Update

PURPOSE

The increasing burden of invasive fungal infections results in growing challenges to antifungal (AF) therapeutic drug monitoring (TDM). This review aims to provide an overview of recent advances in AF TDM.

METHODS

We conducted a PubMed search for articles during 2016-2020 using "TDM" or "pharmacokinetics" or "drug-drug-interaction" with "antifungal," consolidated for each AF. Selection was limited to English language articles with human data on drug exposure.

RESULTS

More than 1000 articles matched the search terms. We selected 566 publications. The latest findings tend to confirm previous observations in real-life clinical settings. The pharmacokinetic variability related to special populations is not specific but must be considered. AF benefit-to-risk ratio, drug-drug interaction (DDI) profiles, and minimal inhibitory concentrations for pathogens must be known to manage at-risk situations and patients. Itraconazole has replaced ketoconazole in healthy volunteers DDI studies. Physiologically based pharmacokinetic modeling is widely used to assess metabolic azole DDI. AF prophylactic use was studied more for Aspergillus spp. and Mucorales in oncohematology and solid organ transplantation than for Candida (already studied). Emergence of central nervous system infection and severe infections in immunocompetent individuals both merit special attention. TDM is more challenging for azoles than amphotericin B and echinocandins. Fewer TDM requirements exist for fluconazole and isavuconazole (ISZ); however, ISZ is frequently used in clinical situations in which TDM is recommended. Voriconazole remains the most challenging of the AF, with toxicity limiting high-dose treatments. Moreover, alternative treatments (posaconazole tablets, ISZ) are now available.

CONCLUSIONS

TDM seems to be crucial for curative and/or long-term maintenance treatment in highly variable patients. TDM poses fewer cost issues than the drugs themselves or subsequent treatment issues. The integration of clinical pharmacology into multidisciplinary management is now increasingly seen as a part of patient care.

Localized genitourinary tract Aspergillus infection in an immunocompetent patient: Bladder and epidydimal aspergillosis

Invasive bladder Aspergillosis has only been reported in six publications so far.

A 74-year-old male, presented to the emergency department with fever, abdominal pain, and right testicular enlargement. Abdominal computed tomography concluded a bladder tumor and testicular ultrasound reported right epididymitis. Cystoscopy showed a bladder fungal mass, which was extracted with cystotomy. Pathological findings reported Aspergillus species. The patient was successfully treated with 4-week oral Isovuconazole.

The first bladder Aspergillosis was published in 1978. The most recent case was published in 2020.

Aspergillosis infection is extremely rare disease, treatment with Isavuconazole is efficient.

Population Pharmacokinetics and Pharmacodynamic Target Attainment of Isavuconazole against Aspergillus fumigatus and Aspergillus flavus in Adult Patients with Invasive Fungal Diseases: Should Therapeutic Drug Monitoring for Isavuconazole Be Considered as Mandatory as for the Other Mold-Active Azoles?

Isavuconazole is a newer broad-spectrum triazole approved for the treatment of invasive fungal disease. The objective of this study was to conduct a population pharmacokinetic and pharmacodynamic analysis of isavuconazole in a retrospective cohort of hospitalized patients. A nonlinear mixed-effect approach with Monte Carlo simulations was conducted to assess the probability of target attainment (PTA) of an area under the concentration–time curve (AUC_{24 h})/minimum inhibitory concentration (MIC) ratio of 33.4 (defined as efficacy threshold against A. fumigatus and A. flavus) associated with a maintenance dose (MD) of 100, 200 and 300 mg daily after loading. The cumulative fraction of response (CFR) against the EUCAST MIC distributions of A. fumigatus and A. flavus was calculated as well. The proportion of trough concentrations (C_trough) exceeding a defined threshold of toxicity (>5.13 mg/L) was estimated. A total of 50 patients, with a median age of 61.5 years, provided 199 plasma isavuconazole concentrations. Invasive pulmonary aspergillosis was the prevalent type of infection and accounted for 80% (40/50) of cases. No clinical covariates were retained by the model. With the standard MD of 200 mg daily, CFRs were always ≥90% during the first two months of treatment. The risk of C_trough < 1.0 mg/L was around 1%, and that of C_trough > 5.13 mg/L was 27.7 and 39.2% at 28 and 60 days, respectively, due to isavuconazole accumulation over time. Our findings suggest that TDM for isavuconazole should not be considered as mandatory as for the other mold-active azoles voriconazole and posaconazole.

High-throughput simultaneousquantification offive azole anti-fungal agents and one active metabolite in human plasma using ultra-high-performance liquid chromatography coupled to tandem mass spectrometry

OBJECTIVES

For patients with hematological malignancy, triazole antifungal agents such as fluconazole (FLCZ), itraconazole (ITCZ), voriconazole (VRCZ), posaconazole (PSCZ) and isavuconazole (ISCZ) are often used for prophylaxis of deep mycosis. Since these azoles exhibit large pharmacokinetic variability, dose adjustment by therapeutic drug monitoring is recommended for some azoles. This study aimed to develop and validate a novel method for simultaneous determination of plasma concentrations of FLCZ, ITCZ, VRCZ, PSCZ, ISCZ and ITCZ-OH, an active metabolite of ITCZ, using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS).

DESIGN & METHODS

A high-throughput solid-phase extraction method using 96-well MCX µElution Plate was selected as the pretreatment procedure.

RESULTS

The calibration curves for FLCZ, ITCZ, ITCZ-OH, VRCZ, PSCZ and ISCZ showed good linearity (back-calculation of calibrators: relative error ≤ 15% [LLOQ: ≤ 20%]) over wide ranges of 100-100000, 20-20000, 40-40000, 20-20000, 5-5000 and 50-50000 ng/mL, respectively. The validation results of all six drugs fulfilled the criteria of the guidance for bioanalytical method validation of the US Food and Drug Administration for within-batch and batch-to-batch precision and accuracy. The extraction recovery rates were good at ≥ 74.9%, and almost no matrix effects were found for all the drugs. The trough (10 h post-dose in 1 patient on PSCZ) drug concentrations in patients with hematologic malignancy who received oral FLCZ, ITCZ, VRCZ or PSCZ were quantified using the method developed. The measurements for all samples were within the ranges of the calibration curves, demonstrating the feasibility of clinical application of the novel method.

CONCLUSIONS

We have succeeded in developing a novel high-throughput method using UHPLC-MS/MS for simultaneous quantification of plasma concentrations of FLCZ, ITCZ, ITCZ-OH, VRCZ, PSCZ and ISCZ.

Isavuconazole Is as Effective as and Better Tolerated Than Voriconazole for Antifungal Prophylaxis in Lung Transplant Recipients

BACKGROUND

Invasive fungal infections (IFIs) are common following lung transplantation. Isavuconazole is unstudied as prophylaxis in organ transplant recipients. We compared effectiveness and tolerability of isavuconazole and voriconazole prophylaxis in lung transplant recipients.

METHODS

A single-center, retrospective study of patients who received isavuconazole (September 2015-February 2018) or voriconazole (September 2013-September 2015) for antifungal prophylaxis. IFIs were defined by EORTC/MSG criteria.

RESULTS

Patients received isavuconazole (n = 144) or voriconazole (n = 156) for median 3.4 and 3.1 months, respectively. Adjunctive inhaled amphotericin B (iAmB) was administered to 100% and 41% of patients in the respective groups. At 1 year, 8% of patients receiving isavuconazole or voriconazole developed IFIs. For both groups, 70% and 30% of IFIs were caused by molds and yeasts, respectively, and breakthrough IFI (bIFI) rate was 3%. Outcomes did not significantly differ for patients receiving or not receiving iAmB. Independent risk factors for bIFI and breakthrough invasive mold infection (bIMI) were mold-positive respiratory culture and red blood cell transfusion >7 units at transplant. Bronchial necrosis >2 cm from anastomosis and basiliximab induction were also independent risk factors for bIMI. Isavuconazole and voriconazole were discontinued prematurely due to adverse events in 11% and 36% of patients, respectively (P = .0001). Most common causes of voriconazole and isavuconazole discontinuation were hepatotoxicity and lack of oral intake, respectively. Patients receiving ≥90 days prophylaxis had fewer IFIs at 1 year (3% vs 9%, P = .02). IFIs were associated with increased mortality (P = .0001) and longer hospitalizations (P = .0005).

CONCLUSIONS

Isavuconazole was effective and well tolerated as antifungal prophylaxis following lung transplantation.

Achievement of clinical isavuconazole blood concentrations in transplant recipients with isavuconazonium sulphate capsules administered via enteral feeding tube

BACKGROUND

Isavuconazole is a triazole antifungal available in IV and capsule formulation. Prescribing information states that capsules should not be chewed, crushed, dissolved or opened because the drug was not studied in this manner. However, considering the pharmacokinetics of the capsules, we theorized opening and sprinkling the contents into an enteral feeding tube (EFT) would result in adequate absorption and systemic concentrations of isavuconazole.

OBJECTIVES

To determine whether patients receiving isavuconazonium sulphate capsules via EFT would achieve clinical blood concentrations of isavuconazole.

METHODS

Nineteen solid organ and HCT recipients receiving isavuconazole via EFT for prevention or treatment of invasive fungal infection (IFI) were prospectively identified at four academic medical centres in the USA. Patients were included in this evaluation if they received isavuconazole via EFT for at least 5 days and therapeutic drug monitoring (TDM) was performed.

RESULTS

TDM was performed after a median of 7 days (range 6-17) following EFT administration and 15 days (range 7-174) of isavuconazole therapy overall. Median isavuconazole concentration was 1.8 μg/mL (range 0.3-5.2). Median isavuconazole concentrations in patients with or without prior IV administration were 1.8 μg/mL (range 0.3-5.2) and 2.2 μg/mL (range 0.8-3.6; P = 0.896), respectively. Concentrations achieved with the EFT route were similar to or greater than the corresponding concentrations via the IV route in six patients who had TDM performed during both routes of administration.

CONCLUSIONS

It is reasonable to consider opening isavuconazonium sulphate capsules and administering the contents enterally for prevention and treatment of IFI.

A physiologically based pharmacokinetic analysis to predict the pharmacokinetics of intravenous isavuconazole in patients with or without hepatic impairment

Isavuconazole (ISA) is an azole antifungal used in the treatment of invasive aspergillosis and mucormycosis. Patients with mild and moderate hepatic impairment have lower clearance (CL) as compared to the healthy population. Currently, there is no data on ISA in patients with severe hepatic impairment (Child-Pugh Class C). The purpose of this study was to build a physiologically based pharmacokinetic (PBPK) model to describe the pharmacokinetics (PK) of intravenous ISA, and to predict changes in ISA disposition in different patient populations and in patients with hepatic impairment to guide personalized dosing. By incorporating the systemic and drug specific parameters of ISA, the model was initially developed in healthy population and validated with 10 independent PK profiles obtained from healthy subjects and from patients with normal liver function. The results showed a satisfactory predictive capacity, with most of the relative predictive errors being between ±30% for area under the curve (AUC) and C_max The observed plasma concentration-time profiles of ISA were well described by the model predicted profiles. The model adequately predicted the reduced CL of ISA in patients with mild and moderate hepatic impairment. Furthermore, the model predicted a decrease in CL of about 60% in patients with severe hepatic impairment. Therefore, we recommend reducing the dose by 50% in patients with severe hepatic impairment. The model also predicted differences in the PK of ISA between Caucasian and Asian population, with the CL ratio of 0.67 in Chinese vs Caucasian population. The developed PBPK model of ISA provides a reasonable approach for optimizing the dosage regimen in different ethnic populations and in patients with severe hepatic impairment.

Invasive aspergillosis in solid organ transplant patients: diagnosis, prophylaxis, treatment, and assessment of response

BACKGROUND

Invasive aspergillosis (IA) is a rare complication in solid organ transplant (SOT) recipients. Although IA has significant implications on graft and patient survival, data on diagnosis and management of this infection in SOT recipients are still limited.

METHODS

Discussion of current practices and limitations in the diagnosis, prophylaxis, and treatment of IA and proposal of means of assessing treatment response in SOT recipients.

RESULTS

Liver, lung, heart or kidney transplant recipients have common as well as different risk factors to the development of IA, thus each category needs a separate evaluation. Diagnosis of IA in SOT recipients requires a high degree of awareness, because established diagnostic tools may not provide the same sensitivity and specificity observed in the neutropenic population. IA treatment relies primarily on mold-active triazoles, but potential interactions with immunosuppressants and other concomitant therapies need special attention.

CONCLUSIONS

Criteria to assess response have not been sufficiently evaluated in the SOT population and CT lesion dynamics, and serologic markers may be influenced by the underlying disease and type and severity of immunosuppression. There is a need for well-orchestrated efforts to study IA diagnosis and management in SOT recipients and to develop comprehensive guidelines for this population.

Review of Pharmacologic Considerations in the Use of Azole Antifungals in Lung Transplant Recipients

Mold-active azole antifungals are commonly prescribed for the prevention of invasive fungal infections in lung transplant recipients. Each agent exhibits a unique pharmacologic profile, an understanding of which is crucial for therapy selection and optimization. This article reviews pharmacologic considerations for three frequently-used azole antifungals in lung transplant recipients: voriconazole, posaconazole, and isavuconazole. Focus is drawn to analysis of drug-interactions, adverse drug reactions, pharmacokinetic considerations, and the role of therapeutic drug monitoring with special emphasis on data from the post-lung transplant population.