Pharmacological management of invasive mold infections in solid organ transplant recipients

INTRODUCTION

Solid organ transplant (SOT) recipients face an increased susceptibility to invasive fungal infection (IFI) due to filamentous fungi. Post-transplant invasive aspergillosis (IA) and mucormycosis are related to exceedingly high mortality rates and graft loss risk, and its management involve a unique range of clinical challenges.

AREAS COVERED

First, the current treatment recommendations for IA and mucormycosis among SOT recipients are critically reviewed, including the supporting evidence. Next, we discussed particular concerns in this patient population, such as drug-drug interactions (DDIs) between triazoles and post-transplant immunosuppression or treatment-related toxicity. The role for immunomodulatory and host-targeted therapies is also considered, as well as the theoretical impact of the intrinsic antifungal activity of calcineurin inhibitors. Finally, a personal opinion is made on future directions in the pharmacological approach to post-transplant IFI.

EXPERT OPINION

Despite relevant advances in the treatment of mold IFIs in the SOT setting, such as the incorporation of isavuconazole (with lower incidence of DDIs and better tolerability than voriconazole), there remains a large room for improvement in areas such as the position of combination therapy or the optimal strategy for the reduction of baseline immunosuppression. Importantly, future studies should define the specific contribution of newer antifungal agents and classes.

Trends of Azole Antifungal Prescription in the United States: Medicare Part D Provider Utilization and Payment Data Analysis

Background

Invasive fungal infections carry a substantial risk of mortality and morbidity. Azole antifungals are used in the treatment of such infections; however, their extensive use can lead to the emergence of antifungal resistance and increased costs to patients and healthcare systems. The aim of this study is to evaluate trends in these antifungals use and costs.

Methods

The secular and regional trends of outpatient azole antifungals were analyzed using Medicare Part D Prescriber Public Use Files for the years 2013-2020. The total days supply (TDS), total drug cost (TDC) per 100 000 enrollees, and cost per day (CPD) were evaluated.

Results

The azole antifungal TDS for Medicare Part D enrollees increased by 12% between 2013 and 2020, and increases were noted for each azole. Southern US regions had the highest TDS, with Arizona having the highest TDS among US states in 2020. Cost analysis showed that TDC of all azoles has increased by 93% over the years, going up from $123 316 in 2013 to $238 336 per 100 000 enrollees in 2020. However, CPD showed an increase only for fluconazole and isavuconazole, with CPD of $1.62 per day and $188.30 per day, respectively.

Conclusions

Combined azole antifungal prescriptions TDS increased among Medicare Part D enrollees. The trend in CPD was mixed, whereas overall costs consistently increased over the same period. Such findings provide an insight into the impact of azole antifungal prescriptions, and increasing use could foreshadow more antifungal resistance. Continued studies to evaluate different prescribers' trends are warranted.

Microdialysis of Voriconazole and its N-Oxide Metabolite: Amalgamating Knowledge of Distribution and Metabolism Processes in Humans

PURPOSE

Voriconazole is an essential antifungal drug whose complex pharmacokinetics with high interindividual variability impedes effective and safe therapy. By application of the minimally-invasive sampling technique microdialysis, interstitial space fluid (ISF) concentrations of VRC and its potentially toxic N-oxide metabolite (NO) were assessed to evaluate target-site exposure for further elucidating VRC pharmacokinetics.

METHODS

Plasma and ISF samples of a clinical trial with an approved VRC dosing regimen were analyzed for VRC and NO concentrations. Concentration-time profiles, exposure assessed as area-under-the-curve (AUC) and metabolic ratios of four healthy adults in plasma and ISF were evaluated regarding the impact of multiple dosing and CYP2C19 genotype.

RESULTS

VRC and NO revealed distribution into ISF with AUC values being ≤2.82- and 17.7-fold lower compared to plasma, respectively. Intraindividual variability of metabolic ratios was largest after the first VRC dose administration while interindividual variability increased with multiple dosing. The CYP2C19 genotype influenced interindividual differences with a maximum 6- and 24-fold larger AUCNO/AUCVRC ratio between the intermediate and rapid metabolizer in plasma and ISF, respectively. VRC metabolism was saturated/auto-inhibited indicated by substantially decreasing metabolic concentration ratios with increasing VRC concentrations and after multiple dosing.

CONCLUSION

The feasibility of the simultaneous microdialysis of VRC and NO in vivo was demonstrated and provided new quantitative insights by leveraging distribution and metabolism processes of VRC in humans. The exploratory analysis suggested substantial dissimilarities of VRC and NO pharmacokinetics in plasma and ISF. Ultimately, a thorough understanding of target-site pharmacokinetics might contribute to the optimization of personalized VRC dosing regimens.

Microdialysis of Drug and Drug Metabolite: a Comprehensive In Vitro Analysis for Voriconazole and Voriconazole N-oxide

PURPOSE

Voriconazole is a therapeutically challenging antifungal drug associated with high interindividual pharmacokinetic variability. As a prerequisite to performing clinical trials using the minimally-invasive sampling technique microdialysis, a comprehensive in vitro microdialysis characterization of voriconazole (VRC) and its potentially toxic N-oxide metabolite (NO) was performed.

METHODS

The feasibility of simultaneous microdialysis of VRC and NO was explored in vitro by investigating the relative recovery (RR) of both compounds in the absence and presence of the other. The dependency of RR on compound combination, concentration, microdialysis catheter and study day was evaluated and quantified by linear mixed-effects modeling.

RESULTS

Median RR of VRC and NO during individual microdialysis were high (87.6% and 91.1%). During simultaneous microdialysis of VRC and NO, median RR did not change (87.9% and 91.1%). The linear mixed-effects model confirmed the absence of significant differences between RR of VRC and NO during individual and simultaneous microdialysis as well as between the two compounds (p > 0.05). No concentration dependency of RR was found (p = 0.284). The study day was the main source of variability (46.3%) while the microdialysis catheter only had a minor effect (4.33%). VRC retrodialysis proved feasible as catheter calibration for both compounds.

CONCLUSION

These in vitro microdialysis results encourage the application of microdialysis in clinical trials to assess target-site concentrations of VRC and NO. This can support the generation of a coherent understanding of VRC pharmacokinetics and its sources of variability. Ultimately, a better understanding of human VRC pharmacokinetics might contribute to the development of personalized dosing strategies.

Challenges in the Treatment of Invasive Aspergillosis in Immunocompromised Children

Invasive aspergillosis (IA) is associated with significant morbidity and mortality. Voriconazole remains the drug of choice for the treatment of IA in children; however, the complex kinetics of voriconazole in children make dosing challenging and therapeutic drug monitoring (TDM) essential for treatment success. The overarching goal of this review is to discuss the role of voriconazole, posaconazole, isavuconazole, liposomal amphotericin B, echinocandins, and combination antifungal therapy for the treatment of IA in children. We also provide a detailed discussion of antifungal TDM in children.

Update on the Epidemiology, Diagnosis, and Treatment of Coccidioidomycosis

Coccidioidomycosis is a fungal infection caused by Coccidioides immitis and Coccidioides posadasii. The dimorphic fungi live in the soils of arid and semi-arid regions of the western United States, as well as parts of Mexico, Central America, and South America. Incidence of disease has risen consistently in recent years, and the geographic distribution of Coccidioides spp. appears to be expanding beyond previously known areas of endemicity. Climate factors are predicted to further extend the range of environments suitable for the growth and dispersal of Coccidioides species. Most infections are asymptomatic, though a small proportion result in severe or life-threatening forms of disease. Primary pulmonary coccidioidomycosis is commonly mistaken for community-acquired pneumonia, often leading to inappropriate antibacterial treatment and unnecessary healthcare costs. Diagnosis of coccidioidomycosis is challenging and often relies on clinician suspicion to pursue laboratory testing. Advancements in diagnostic tools and antifungal therapy developments seek to improve the early detection and effective management of infection. This review will highlight recent updates and summarize the current understanding of the epidemiology, diagnosis, and treatment of coccidioidomycosis.

Evaluation of voriconazole related adverse events in pediatric patients with hematological malignancies

BACKGROUND

Despite therapeutic drug monitoring and pharmacogenetic-guided dose selection are recommended for pediatric patients, safety of voriconazole is mostly monitored by clinical assessment. Having comprehensive knowledge of safety profile and distinguishing incidental events from the reactions that are truly related to voriconazole use are crucial for safer and uninterrupted treatment.

OBJECTIVES

This study aimed to address adverse reactions during the first month of voriconazole use by systematically evaluating retrospective records of all adverse events. Patients/Methods: It is a single-center, retrospective analysis of patients who received voriconazole from 1 September 2010 to 1 September 2020. Severity of abnormal findings in medical records were systematically graded. Causality between voriconazole and the events was evaluated by Liverpool Causality Assessment Tool (LCAT), Naranjo Algorithm and World Health Organization Causality Assessment System. The events with possible or probable causal relation to voriconazole are classified as adverse reaction.

RESULTS

Records of 45 patients included in the study. The overall frequency of adverse reactions was 51.1%. Hepatobiliary laboratory adverse reactions identified in 48.9% of the patients and led to treatment discontinuation in 20.0%. Amylase and lipase elevation (2.2%), ventricular extra systoles (2.2%), hallucination and nightmares (2.2%) were other adverse reactions.

CONCLUSIONS

Hepatobiliary abnormalities were the most common adverse reactions and the most common cause of treatment discontinuation. For safer treatment in critically ill patients, the dose should be personalized. To clearly identify the accurate frequency and the causality of all adverse reactions, prospective studies with much larger sample size are needed.

Towards the Elucidation of the Pharmacokinetics of Voriconazole: A Quantitative Characterization of Its Metabolism

The small-molecule drug voriconazole (VRC) shows a complex and not yet fully understood metabolism. Consequently, its in vivo pharmacokinetics are challenging to predict, leading to therapy failures or adverse events. Thus, a quantitative in vitro characterization of the metabolism and inhibition properties of VRC for human CYP enzymes was aimed for. The Michaelis-Menten kinetics of voriconazole N-oxide (NO) formation, the major circulating metabolite, by CYP2C19, CYP2C9 and CYP3A4, was determined in incubations of human recombinant CYP enzymes and liver and intestine microsomes. The contribution of the individual enzymes to NO formation was 63.1% CYP2C19, 13.4% CYP2C9 and 29.5% CYP3A4 as determined by specific CYP inhibition in microsomes and intersystem extrapolation factors. The type of inhibition and inhibitory potential of VRC, NO and hydroxyvoriconazole (OH-VRC), emerging to be formed independently of CYP enzymes, were evaluated by their effects on CYP marker reactions. Time-independent inhibition by VRC, NO and OH-VRC was observed on all three enzymes with NO being the weakest and VRC and OH-VRC being comparably strong inhibitors of CYP2C9 and CYP3A4. CYP2C19 was significantly inhibited by VRC only. Overall, the quantitative in vitro evaluations of the metabolism contributed to the elucidation of the pharmacokinetics of VRC and provided a basis for physiologically-based pharmacokinetic modeling and thus VRC treatment optimization.

A versatile high-performance LC-MS/MS assay for the quantification of voriconazole and its N-oxide metabolite in small sample volumes of multiple human matrices for biomedical applications

Voriconazole (VRC) pharmacokinetics, in particular its complex metabolism, is still not fully understood which challenges its optimal therapeutic use. To increase knowledge on the pharmacokinetics of this antifungal drug, it is essential to broaden the perspective and expand in vitro and clinical in vivo investigations in particular to aspects such as unbound plasma, target-site and metabolite concentrations. Innovative sampling approaches such as microdialysis, a minimally-invasive technique for the analysis of compound concentrations in target-site human tissue fluids, are associated with bioanalytical challenges, i.e. small sample volumes and low concentrations. Thus, a bioanalytical LC-MS/MS assay for the simultaneous quantification of VRC and its main N-oxide (NO) metabolite in human plasma, ultrafiltrate and microdialysate was developed and validated according to the European Medicines Agency guideline. Quantification was rapid, simple and feasible for clinically relevant concentrations from 5 to 5000 ng/mL in plasma and ultrafiltrate as well as from 4 to 4000 ng/mL in microdialysate. Due to the high sensitivity of the assay, only 20 µL of plasma or ultrafiltrate and 5 µL of microdialysate were required. For VRC and NO in all matrices, between-run accuracy was high with a maximum mean deviation of 7.0% from the nominal value and between-run precision was demonstrated by ≤ 11.8% coefficient of variation. Both compounds proved stable under various conditions. The assay suitability was demonstrated by the application to a clinical study quantifying simultaneously VRC and NO concentrations in plasma, ultrafiltrate and microdialysate. Additionally, the assay was successfully adapted for pharmacokinetic analyses in human tissue-derived in vitro experiments. Overall, by reducing the required sample volume, the bioanalytical method allows for an increased number of plasma samples in vulnerable populations, e.g. infants, and enables the generation of concentration-time profiles with a higher temporal resolution in microdialysis studies. Consequently, the developed assay is apt to elucidate the complex pharmacokinetics of VRC in clinical settings as prerequisite for therapy optimisation.

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.

Antimicrobial Resistance and Antimicrobial Nanomaterials

Back in the mid-nineties, the discovery of antimicrobials denoted a profound and remarkable achievement in medicine which was capable of saving lives. However, recently, antimicrobial resistance became a major global issue facing modern medicine and significantly increased among bacteria, fungi, and viruses which results in reduced efficacy of many clinically important and lifesaving antimicrobials. The growing rise of antimicrobial resistance inflicts a remarkable economic and social burden on the health care system globally. The replacement of conventional antimicrobials by new technology to counteract and lessen antimicrobial resistance is currently ongoing. Nanotechnology is an advanced approach to overcome challenges of such resisted conventional drug delivery systems mainly based on the development and fabrication of nanoparticulate structures. Numerous forms of nanoparticulate systems have been discovered and tried as prospective drug delivery systems, comprising organic and inorganic nanoparticles.

Antimicrobial Resistance and Antimicrobial Nanomaterials

Back in the mid-nineties, the discovery of antimicrobials denoted a profound and remarkable achievement in medicine which was capable of saving lives. However, recently, antimicrobial resistance became a major global issue facing modern medicine and significantly increased among bacteria, fungi, and viruses which results in reduced efficacy of many clinically important and lifesaving antimicrobials. The growing rise of antimicrobial resistance inflicts a remarkable economic and social burden on the health care system globally. The replacement of conventional antimicrobials by new technology to counteract and lessen antimicrobial resistance is currently ongoing. Nanotechnology is an advanced approach to overcome challenges of such resisted conventional drug delivery systems mainly based on the development and fabrication of nanoparticulate structures. Numerous forms of nanoparticulate systems have been discovered and tried as prospective drug delivery systems, comprising organic and inorganic nanoparticles.

Generalized exfoliative skin rash as an early predictor of supratherapeutic voriconazole trough levels in a leukemic child: A case report

Background and Purpose:

Skin rashes, mostly seen in children and adolescents, are considered among the most common side effects of azole antifungals. Although therapeutic concentrations of voriconazole (VCZ) have been documented for infected skin, there is no evidence specifying whether specific dermatologic side effects could predict high VCZ serum concentration, especially in high-risk leukemic children.

Case report:

Herein, we report a unique skin side effect of VCZ in a 5-year-old boy with T-cell acute lymphoblastic leukemia (ALL) referred to Amir Medical Oncology Center in Shiraz, Iran. The patient experienced erythroderma and macular rashes shortly after VCZ consumption, leading to generalized exfoliative skin rashes. Concurrent to these skin manifestations, VCZ serum concentration reached the supratherapeutic levels despite the recommended VCZ doses. As a result, VCZ was withheld, and the patient was treated with caspofungin. The lesions were resolved gradually within 2 weeks, and the patient successfully completed his treatment course with caspofungin.

Conclusion:

The unique case presented in this study emphasizes the need for a high index of suspicion for VCZ toxicity in any patient with atypical dermatologic manifestations, especially generalized exfoliative skin rashes. Based on this report, VCZ supratherapeutic concentration could be predicted early in the course of treatment. Additional therapeutic dose monitoring should be considered to establish a confirmatory diagnosis. It is required to further investigate the toxic effect of high VCZ concentration on the skin epithelium.

Voriconazole-Induced Squamous Cell Carcinoma after Hematopoietic Stem Cell Transplantation Showing Early-Stage Vascular Invasion

Voriconazole is a triazole antifungal agent used for the prevention and treatment of fungal infections in immunocompromised patients. Prolonged voriconazole therapy may induce phototoxicity and lead to the development of malignant neoplasms of the epidermis, such as squamous cell carcinoma (SCC), especially in immunocompromised patients. We report a case of voriconazole-induced phototoxicity and SCC occurring after hematopoietic stem cell transplantation (HSCT) in a 56-year-old man with primary myelofibrosis. The patient developed chronic graft-versus-host disease (GVHD) post-transplantation and had been receiving long-term immunosuppressive treatment. A year after the initiation of voriconazole therapy for prophylaxis, he developed keratotic erythema, followed by SCC with vascular invasion after three years. A review of SCC in HSCT recipients suggests that the prolonged use of voriconazole is regarded as a risk for SCC after HSCT in patients with chronic GVHD on immunosuppressive therapy. Moreover, a histological examination of the completely resected tumor revealed vascular invasion in this case, although neither the clinical features nor the histological findings of the preoperative biopsy suggested invasive carcinoma. This case may partially explain why voriconazole-associated SCCs show a more aggressive clinical course than non-voriconazole SCCs do.

Successful treatment of Aspergillus fumigatus sternal osteomyelitis with isavuconazole in a heart transplant recipient

A 65-year-old man was diagnosed with an invasive Aspergillus fumigatus infection with sternal osteomyelitis 4 months after heart transplantation. Unfortunately, after 8 weeks patient developed severe cutaneous and neurological toxicities induced by voriconazole leading to drug discontinuation. Therefore, isavuconazole was chosen as second-line therapy. The patient presented a favorable outcome and tolerance was excellent after ten months monotherapy. Here, we report for a first time, an successful isavuconazole-based treatment of sternal osteomyelitis aspergillosis in a cardiac recipient.

[Voriconazole-induced lentigines on photo-exposed skin: A little-known complication]

BACKGROUND

The appearance of diffuse lentigines in children is rare and a genetic syndrome should initially be envisaged. Another little-known cause of photo-distributed lentigines is use of voriconazole. We present a new case in which the original feature is the very short time of onset.

PATIENTS AND METHODS

A 9-year-old immunosuppressed girl treated with voriconazole for 3 months presented lentigines in exposed areas after only 4 weeks of exposure.

DISCUSSION

The literature contains only around ten cases of photo-distributed lentigines under voriconazole in children. The condition can appear very early, as in our case. Voriconazole also appears to induce cutaneous squamous cell carcinomas and even melanoma. The benefit-risk ratio of prescribing this drug must therefore be carefully evaluated, and close clinical monitoring and photoprotection must be instituted.

Make Sure You Have a Safety Net: Updates in the Prevention and Management of Infectious Complications in Stem Cell Transplant Recipients

Hematopoietic stem cell transplant recipients are at increased risk of infection and immune dysregulation due to reception of cytotoxic chemotherapy; development of graft versus host disease, which necessitates treatment with immunosuppressive medications; and placement of invasive catheters. The prevention and management of infections in these vulnerable hosts is of utmost importance and a key “safety net” in stem cell transplantation. In this review, we provide updates on the prevention and management of CMV infection; invasive fungal infections; bacterial infections; Clostridium difficile infection; and EBV, HHV-6, adenovirus and BK infections. We discuss novel drugs, such as letermovir, isavuconazole, meropenem-vaborbactam and bezlotoxumab; weigh the pros and cons of using fluoroquinolone prophylaxis during neutropenia after stem cell transplantation; and provide updates on important viral infections after hematopoietic stem cell transplant (HSCT). Optimizing the prevention and management of infectious diseases by using the best available evidence will contribute to better outcomes for stem cell transplant recipients, and provide the best possible “safety net” for these immunocompromised hosts.

Voriconazole enhances UV-induced DNA damage by inhibiting catalase and promoting oxidative stress

Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer and is associated with cumulative UV exposure. Studies have shown that prolonged voriconazole use promotes cSCC formation; however, the biological mechanisms responsible for the increased incidence remain unclear. Here, we show that voriconazole directly increases oxidative stress in human keratinocytes and promotes UV-induced DNA damage as determined by comet assay, 8-oxoguanine immunofluorescence and mass spectrometry. Voriconazole treatment of human keratinocytes potentiates UV-induced apoptosis and activation of the p38 MAP kinase and 53BP1 UV stress response pathways. The p38 MAP kinase activation promoted by voriconazole exposure can be mitigated by pretreating keratinocytes with N-acetylcysteine. Voriconazole increases oxidative stress in keratinocytes by directly inhibiting catalase leading to lower intracellular NADPH levels and the triazole moieties in voriconazole are critical for inhibiting catalase. Furthermore, voriconazole is shown to promote UV-induced dysplasia in an in vivo model. Together, these data demonstrate that voriconazole potentiates oxidative stress in UV-irradiated keratinocytes through catalase inhibition. Use of antioxidants may mitigate the pro-oncogenic effects of voriconazole.

Airway mycosis in allergic airway disease

The allergic airway diseases, including chronic rhinosinusitis (CRS), asthma, allergic bronchopulmonary mycosis (ABPM) and many others, comprise a heterogeneous collection of inflammatory disorders affecting the upper and lower airways and lung parenchyma that represent the most common chronic diseases of humanity. In addition to their shared tissue tropism, the allergic airway diseases are characterized by a distinct pattern of inflammation involving the accumulation of eosinophils, type 2 macrophages, innate lymphoid cells type 2 (ILC2), IgE-secreting B cells, and T helper type 2 (Th2) cells in airway tissues, and the prominent production of type 2 cytokines including interleukin (IL-) 33, IL-4, IL-5, IL-13, and many others. These factors and related inflammatory molecules induce characteristic remodeling and other changes of the airways that include goblet cell metaplasia, enhanced mucus secretion, smooth muscle hypertrophy, tissue swelling and polyp formation that account for the major clinical manifestations of nasal obstruction, headache, hyposmia, cough, shortness of breath, chest pain, wheezing, and, in the most severe cases of lower airway disease, death due to respiratory failure or disseminated, systemic disease. The syndromic nature of the allergic airway diseases that now include many physiological variants or endotypes suggests that distinct endogenous or environmental factors underlie their expression. However, findings from different perspectives now collectively link these disorders to a single infectious source, the fungi, and a molecular pathogenesis that involves the local production of airway proteinases by these organisms. In this review, we discuss the evidence linking fungi and their proteinases to the surprisingly wide variety of chronic airway and systemic disorders and the immune pathogenesis of these conditions as they relate to environmental fungi. We further discuss the important implications these new findings have for the diagnosis and future therapy of these common conditions.

[Hydrochlorothiazide use and risk of skin cancers: A systematic review]

The risk of skin cancer induced by photosensiting drugs is well known. An association between hydrochlorothiazide use and skin cancer has been recently published in some epidemiological studies. A systematic review of case-control or prospectives cohorts showed an increased risk of cutaneous squamous cell carcinoma even if some confusing factors such as tobacco smoking was not analysed. Results are more conflicting for basal cell carcinoma or melanoma. These results do not modify the benefit/risk ratio but should lead to propose preventive mesures: identification of high risk population, avoidance of this drug if possible in immunocompromised patients or with previous skin cancer, regular skin examination in case of long term use of hydrochlorothiazide.

Current Concepts and Future Directions in the Pharmacology and Treatment of Coccidioidomycosis

Coccidioidomycosis remains a significant clinical problem with substantial morbidity and mortality. The vast majority of infections are asymptomatic and the need for early primary therapy remains controversial. The use of triazole antifungals has improved tolerability of therapy but concerns about acute and long-term toxicities among available agents limit their use. In addition, recent findings of decreased in vitro fluconazole susceptibility to as many as 37% of Coccidioides spp. isolates raises concerns regarding optimal therapy for these infections as fluconazole is commonly used for therapy including central nervous system disease. Thus, new agents from novel antifungal classes are currently in preclinical and clinical development aimed at reducing toxicity and improving outcomes of these serious infections.

Comparison of Skin Cancer Incidence in Caucasian and Non-Caucasian Liver Vs. Lung Transplant Recipients: A Tale of Two Regimens

BACKGROUND

Organ transplantation is a significant risk factor for the development of skin cancer. The impact of skin type, immunosuppressive regimens, and photosensitizing agents requires further study.

OBJECTIVE

The objective of this study was to compare skin cancer development between Caucasian and non-Caucasian transplant recipients at the University of Southern California.

METHODS

We performed a retrospective chart review of lung and liver transplantations to determine the incidence of post-transplant skin cancer. Participants included patients who underwent lung or liver transplantation between 2005 and 2013 at our institution. Patients included in the study were limited to those who survived through the study observation period.

RESULTS

We analyzed 475 patients who underwent transplantation, including 370 liver transplant recipients and 105 lung transplant recipients. Among these, 46.3% identified as Caucasian, while 53.7% were non-Caucasian. Over a mean follow-up of 7.9 years, 11.8% of Caucasian patients developed at least one skin cancer, compared with 2.7% of non-Caucasians (p < 0.001). However, irrespective of race, skin cancer development was significantly greater in lung compared with liver transplant recipients (20.0% vs. 3.2%, p < 0.001). The standard immunosuppressive and prophylactic regimens were mycophenolate mofetil and tacrolimus based for both transplants. Mycophenolate mofetil was maintained throughout the course in lung transplant patients, whereas this agent was reduced and terminated when possible in liver transplant recipients. In addition, during the years examined, voriconazole, a known photosensitizing agent, was used in lung transplant recipients to prevent aspergillosis.

CONCLUSIONS

Fair skin type increases post-transplant skin cancer development, irrespective of the immunosuppressive regimen. A higher risk of skin cancer is associated with different regimens; in particular photosensitizing agents may increase risk in transplant recipients.

Isavuconazole in the Treatment of Coccidioidal Meningitis

Patients with coccidioidal meningitis require lifelong antifungal therapy. Cumulative toxicity and lack of antifungal efficacy require salvage therapy in the treatment of some patients. In a retrospective review of nine patients with coccidioidal meningitis treated with isavuconazole, successful therapy was seen in three patients and stable disease was confirmed in six patients. Isavuconazole may be a useful addition to the therapeutic choices currently available for coccidioidal meningitis.

Drug-induced phototoxicity: A systematic review

BACKGROUND

Phototoxicity has been attributed to numerous oral drugs over the past 60 years.

OBJECTIVE

Determine the quality of evidence supporting suspected phototoxicity from oral drugs.

METHODS

The MEDLINE and EMBASE databases were searched for all studies that contain original data for drug-induced phototoxicity and were published between May 1959 and December 2016. Study quality was assessed by using a modified Grading of Recommendations, Assessment, Development and Evaluation scale.

RESULTS

The review included 240 eligible studies with a total of 2466 subjects. There were 1134 cases of suspected phototoxicity associated with 129 drugs. Most associations were supported by either very low-quality or low-quality evidence (89.1% of the studies). Medications supported by stronger evidence were vemurafenib, nonsteroidal anti-inflammatory drugs, and antibiotics, specifically, fluoroquinolones and tetracyclines. The most frequently reported drugs were vemurafenib, voriconazole, doxycycline, hydrochlorothiazide, amiodarone, and chlorpromazine. Photobiologic evaluation was performed in only 56 studies (23.3%), whereas challenge-rechallenge was done in 10% of cases.

LIMITATIONS

Only English-language publications were reviewed. Cases of phototoxicity that had been incorrectly categorized as photoallergy would not have been included.

CONCLUSIONS

Most purported associations between oral drugs and phototoxicity are not supported by high-quality evidence. Despite the variable quality of data, clinicians should be aware of the possible consequences of long-term use of culprit drugs.

Voriconazole-induced photocarcinogenesis is promoted by aryl hydrocarbon receptor-dependent COX-2 upregulation

Voriconazole (VRCZ) induces the development of UV-associated skin cancers. The mechanism underlying the VRCZ-induced carcinogenesis has been largely unknown. Here, we showed that VRCZ metabolites plus UVA generated reactive oxygen species and resultant DNA damage of the epidermis, but did not induce substantial apoptosis in human keratinocytes (KCs). Furthermore, VRCZ per se stimulates aryl hydrocarbon receptor (AhR) and upregulates COX-2, which is a pivotal enzyme for the promotion of UV-associated tumors, in an AhR-ARNT dependent manner of the classical (genomic) pathway. Our findings suggest that the phototoxic moieties of VRCZ metabolites may participate in the initiation phase of VRCZ skin cancer, while VRCZ per se promotes the tumor development. Therefore, during VRCZ therapy, sun exposure protection is essential to prevent photocarcinogenesis caused by VRCZ metabolites plus UV. Chemoprevention with selective COX-2 inhibitors may be helpful to repress the development of skin cancers derived from DNA-damaged KCs.

Prolonged voriconazole treatment in a patient with chronic lymphocytic leukemia resulting in a litany of chronic overlapping toxicities

Voriconazole is a triazole antifungal with activity against a number of yeast and mold species including Candida, Aspergillosis, Fusarium, and Coccidioides. Invasive fungal infections are associated with high morbidity and mortality, prolonged treatment courses, and occasionally lifelong suppressive therapy. Voriconazole therapy can result in a number of acute toxicities that clinicians are frequently aware of including hepatotoxicity, visual disturbances, and hallucinations; however, there is limited experience with extended durations of voriconazole therapy. We describe the case of a 62-year-old man who developed Coccidioides meningitis as a result of prolonged neutropenia from treatment for chronic lymphocytic leukemia. He was initially treated with a number of different antifungal agents including voriconazole, liposomal amphotericin B, fluconazole, and itraconazole; however, he developed acute toxicity due to those agents. He was successfully re-challenged with voriconazole, and maintained therapeutic serum concentrations throughout treatment. As a result of prolonged voriconazole exposure of over 14 years, he has suffered a number of toxicities, most significantly including actinic keratosis, squamous cell carcinoma, and skeletal fluorosis. To our knowledge, this is the longest continuous use of voriconazole therapy currently in the literature.

Voriconazole Antifungal Prophylaxis in Children With Malignancies: A Nationwide Study

BACKGROUND

Antifungal prophylaxis (AFP) is recommended in at-risk hematology-oncology patients. We evaluated the safety of AFP with voriconazole (VRC) in pediatric hematology/oncology patients.

MATERIALS AND METHODS

A retrospective study of VRC AFP in children with malignancies hospitalized in all 7 Greek pediatric hematology/oncology centers during 2008 to 2012 was conducted. Patients' demographics, outcome, and adverse event (AE) data were recorded.

RESULTS

Four hundred twenty-nine VRC AFP courses in 249 patients (median age 6 y, 55% boys) were studied. The most common underlying diseases were acute lymphoblastic leukemia (51%), non Hodgkin lymphoma (8.6%), and acute myeloid leukemia (7.7%). The median number of VRC courses per patient was 1.7, whereas the median VRC dose was 7 mg/kg (range, 5 to 7 mg/kg) every 12 hours. During the last 2 weeks before AFP, 51% of the patients had received corticosteroids, 43% suffered from severe neutropenia, and 17.3% from mucositis. The median duration of VRC AFP was 17 days (range, 1 to 31 d). A single breakthrough fungemia due to Candida glabrata was recorded. Only 1 patient died due to the underlying disease. The most common AEs reported in 70/429 (16.3%) courses with ≥1 AE were elevated liver enzymes (50%), hypokalemia (24.3%), and ophthalmological disorders (14.3%). The median time of AE onset was 5 days (range, 1 to 21 d). Among 70 AEs reported, 38.5%, 48.4%, and 12.8% were of grade I, II, and III, respectively.

CONCLUSIONS

VRC prophylaxis in pediatric hematology/oncology patients appears to be well tolerated.

Voriconazole and squamous cell carcinoma after lung transplantation: A multicenter study

This study evaluated the independent contribution of voriconazole to the development of squamous cell carcinoma (SCC) in lung transplant recipients, by attempting to account for important confounding factors, particularly immunosuppression. This international, multicenter, retrospective, cohort study included adult patients who underwent lung transplantation during 2005-2008. Cox regression analysis was used to assess the effects of voriconazole and other azoles, analyzed as time-dependent variables, on the risk of developing biopsy-confirmed SCC. Nine hundred lung transplant recipients were included. Median follow-up time from transplantation to end of follow-up was 3.51 years. In a Cox regression model, exposure to voriconazole alone (adjusted hazard ratio 2.39, 95% confidence interval 1.31-4.37) and exposure to voriconazole and other azole(s) (adjusted hazard ratio 3.45, 95% confidence interval 1.07-11.06) were associated with SCC compared with those unexposed after controlling for important confounders including immunosuppressants. Exposure to voriconazole was associated with increased risk of SCC of the skin in lung transplant recipients. Residual confounding could not be ruled out because of the use of proxy variables to control for some confounders. Benefits of voriconazole use when prescribed to lung transplant recipients should be carefully weighed versus the potential risk of SCC. EU PAS registration number: EUPAS5269.

The pathogenesis of cutaneous squamous cell carcinoma in organ transplant recipients

The pathogenesis of keratinocyte carcinoma following organ transplantation is multifactorial, and recent evidence suggests a complex and often synergistic interplay between the carcinogenic effects of ultraviolet radiation, compromised immune surveillance, direct pro- and anticarcinogenic effects of drugs, oncogenic viruses (in particular, beta-genus human papillomaviruses) and host genetic susceptibility factors. We present an overview of those factors for which there is currently the most convincing evidence and highlight important gaps in our knowledge. In particular, a clear understanding of the interdependence and relative contributions of these co-factors is currently lacking, yet has important implications for rational development of clinically relevant biomarkers and targeted strategies for treatment and prevention of post-transplant keratinocyte cancers.

Effect of voriconazole on risk of nonmelanoma skin cancer after hematopoietic cell transplantation

BACKGROUND

Voriconazole has previously been associated with increased risk for cutaneous squamous cell carcinoma (SCC) in solid organ transplant recipients. Less is known about the risk in patients after hematopoietic cell transplantation (HCT).

OBJECTIVE

We evaluated the effect of voriconazole on the risk for nonmelanoma skin cancer (NMSC), including SCC and basal cell carcionoma, among those who have undergone allogeneic and autologous HCT.

METHODS

In all, 1220 individuals who had undergone allogeneic HCT and 1418 who had undergone autologous HCT were included in a retrospective cohort study. Multivariate analysis included voriconazole exposure and other known risk factors for NMSC.

RESULTS

In multivariate analysis, voriconazole use increased the risk for NMSC (hazard ratio, 1.82; 95% confidence interval, 1.13-2.91) among those who had undergone allogeneic HCT, particularly for SCC (hazard ratio, 2.25; 95% confidence interval, 1.30-3.89). Voriconazole use did not appear to confer increased risk for NMSC among those who had undergone autologous HCT.

LIMITATIONS

This is a retrospective study.

CONCLUSION

Voriconazole use represents an independent factor that may contribute to increased risk specifically for SCC in the allogeneic HCT population.

Fungal Infections Associated with Contaminated Steroid Injections

In mid-September 2012, the largest healthcare-associated outbreak in U.S. history began. Before it was over, 751 patients were reported with fungal meningitis, stroke, spinal or paraspinal infection, or peripheral osteoarticular infection, and 64 (8.5%) died. Most patients had undergone epidural injection, and a few osteoarticular injection, of methylprednisolone acetate that had been manufactured at the New England Compounding Center (NECC). The offending pathogen in most cases was Exserohilum rostratum, a brown-black soil organism that previously was a rare cause of human infection. Three lots of methylprednisolone were contaminated with mold at NECC; the mold from unopened bottles of methylprednisolone was identical by whole-genome sequencing to the mold that was isolated from ill patients. Early cases manifested as meningitis, some patients suffered posterior circulation strokes, and later cases were more likely to present with localized infection at the injection site, including epidural abscess or phlegmon, vertebral diskitis or osteomyelitis, and arachnoiditis with intradural involvement of nerve roots. Many patients with spinal or paraspinal infection required surgical intervention. Recommendations for treatment evolved over the first few weeks of the outbreak. Initially, combination therapy with liposomal amphotericin B and voriconazole was recommended for all patients; later, combination therapy was recommended only for those who were most ill, and voriconazole monotherapy was recommended for most patients. Among those patients who continued antifungal therapy for at least 6 months, outcomes for most appeared to be successful, although a few patients remain on therapy.

High-risk cutaneous squamous cell carcinoma in a Japanese allogeneic bone marrow transplant recipient on long-term voriconazole

Cutaneous squamous cell carcinomas arise as secondary cancers in hematopoietic stem cell transplant survivors. They have been documented primarily in Western cohorts and relatively little is known about their occurrence in Asian hematopoietic stem cell transplant recipients, with no reports of squamous cell carcinomas with high-risk features in Asian patients. We describe a case of a cutaneous squamous cell carcinoma with high-risk features on the scalp of a Japanese bone marrow transplant recipient approximately 6.5 years post-transplant, who was on long-term voriconazole. The history of a photodistributed erythema followed by the appearance of multiple actinic keratoses and solar lentigines, together with the rarity of cutaneous squamous cell carcinomas in Asian hematopoietic stem cell transplant cohorts revealed in our literature review, suggest that voriconazole use contributed to the development of high-risk squamous cell carcinoma in our patient.

Voriconazole increases the risk for cutaneous squamous cell carcinoma after lung transplantation

Lung transplant recipients (LTR) are at high risk of cutaneous squamous cell carcinoma (SCC). Voriconazole exposure after lung transplant has recently been reported as a risk factor for SCC. We sought to study the relationship between fungal prophylaxis with voriconazole and the risk of SCC in sequential cohorts from a single center. We evaluated 400 adult LTR at UCLA between 7/1/2005 and 12/22/2012. On 7/1/2009, our center instituted a protocol switch from targeted to universal antifungal prophylaxis for at least 6 months post-transplant. Using Cox proportional hazards models, time to SCC was compared between targeted (N = 199) and universal (N = 201) prophylaxis cohorts. Cox models were also used to assess SCC risk as a function of time-dependent cumulative exposure to voriconazole and other antifungal agents. The risk of SCC was greater in the universal prophylaxis cohort (HR 2.02, P < 0.01). Voriconazole exposure was greater in the universal prophylaxis cohort, and the cumulative exposure to voriconazole was associated with SCC (HR 1.75, P < 0.01), even after adjustment for other important SCC risk factors. Voriconazole did not increase the risk of advanced tumors. Exposure to other antifungal agents was not associated with SCC. Voriconazole should be used cautiously in this population.

Adverse effects of voriconazole: Over a decade of use

Voriconazole use has increased since the drug's introduction in 2002, and new and unique adverse effects are emerging as patients undergo prolonged therapy. Most concerning is the increased risk of cutaneous malignancies, primarily squamous cell carcinoma (SCC); this risk is duration dependent and the associated malignancies tend to be more aggressive and multifocal. Voriconazole is also associated with phototoxicity (which may be a precursor to malignancy), periostitis, hallucinations and encephalopathy, peripheral neuropathy, alopecia, nail changes, hyponatremia, and other adverse effects. Some toxicities (neuropsychiatric and gastrointestinal including hepatic) are seen in clear association with supratherapeutic serum voriconazole levels; thus, careful monitoring of voriconazole levels is a critical component of safe drug use. Guidelines for screening for adverse effects after long-term voriconazole use may be beneficial and need to be established.

[Opportunistic infections and sarcoidosis]

Opportunistic infections (OI) are uncommon in sarcoidosis (1 to 10%) and mostly occur in patients with previously diagnosed disease or can rarely be the presenting manifestation. The most common OIs are, in descending order: aspergillosis, cryptococcosis, and mycobacterial infections. Treatment with corticosteroids is the most frequent risk factor for OI occurrence during sarcoidosis but immunosuppressive drugs and therapy with anti-TNFα are also risk factors. Overall, clinical presentation, treatment, and outcome are identical to that occur in other conditions complicated with the occurrence of OIs. However, some atypical presentations of OIs can mimic sarcoidosis exacerbation and misdiagnosis may lead clinicians to increase immunosuppression, causing worsening of the OI. The meticulous collection of patient's history along with factors differentiating OI from sarcoidosis exacerbation is key factor to optimally manage these patients.

Drug resistance in eukaryotic microorganisms

Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies.

Voriconazole Exposure and Risk of Cutaneous Squamous Cell Carcinoma, Aspergillus Colonization, Invasive Aspergillosis and Death in Lung Transplant Recipients

Voriconazole is a triazole antifungal used to prevent and treat invasive fungal infections after lung transplantation, but it has been associated with an increased risk of developing cutaneous squamous cell carcinoma (SCC). Despite widespread use, there are no clear guidelines for optimal prophylactic regimens that balance the competing risks and benefits. We conducted a retrospective cohort study of all lung transplant recipients at the University of California, San Francisco, who were transplanted between October 1991 and December 2012 (n = 455) to investigate whether voriconazole exposure affected development of SCC, Aspergillus colonization, invasive aspergillosis and all-cause mortality. Voriconazole exposure was associated with a 73% increased risk of developing SCC (hazard ratio [HR] 1.73; 95% confidence interval [CI]: 1.04-2.88; p = 0.03), with each additional 30-day exposure at the standard dose increasing the risk by 3.0% (HR 1.03; 95% CI: 1.02-1.04; p < 0.001). Voriconazole exposure reduced risk of Aspergillus colonization by 50% (HR 0.50; 95% CI: 0.34-0.72; p < 0.001), but we were underpowered to detect risk reduction for invasive aspergillosis. Voriconazole exposure significantly reduced all-cause mortality among subjects who developed Aspergillus colonization (HR 0.34; 95% CI: 0.13-0.91; p = 0.03) but had no significant impact on those without colonization. Physicians should consider patient-specific factors that modify the potential risks and benefits of voriconazole for the care of lung transplant recipients.

Comparison of clinical pharmacology of voriconazole and posaconazole

Despite greater knowledge and possibilities in pharmacotherapy, fungal infections remain a challenge for clinicians. As the population of immunocompromised patients and those treated for their hematologic ailments increases, the number of fungal infections grows too. This is why there is still a quest for new antifungal drugs as well as for optimization of pharmacotherapy with already registered pharmaceutics.

Voriconazole and posaconazole are broad-spectrum, new generation, triazole antifungal agents. The drugs are used in the pharmacotherapy of invasive aspergillosis, Candida and Fusarium infections. Voriconazole is also used in infections caused by Scedosporium. Posaconazole is used in the treatment of coccidioidomycosis and chromoblastomycosis. Besides some similarities, the two mentioned drugs also show differences in therapeutic indications, pharmacokinetics (mainly absorption and metabolism), frequency and severity of adverse drug reactions, drug–drug interactions and dosage. As both of the drugs are used in the treatment of invasive fungal infections in adults and children, detailed knowledge of the clinical pharmacology of antifungal agents is the main factor in pharmacotherapy optimization in treatment of fungal infections.

The goal of the article is to present and compare the clinical pharmacology of voriconazole and posaconazole as well as to point out the indications and contraindications of using the drugs, determine factors influencing their pharmacotherapy, and provide information that might be helpful in the treatment of fungal infections.

Voriconazole exposure and the risk of cutaneous squamous cell carcinoma in allogeneic hematopoietic stem cell transplant patients

BACKGROUND

Voriconazole is a commonly used antifungal medication in allogeneic hematopoietic stem cell transplantation (allo-HSCT) patients. In solid organ transplantation, voriconazole use has been associated with the development of cutaneous squamous cell carcinoma (SCC). We sought to determine if voriconazole use was associated with SCC in patients undergoing allo-HSCT.

METHODS

We retrospectively reviewed consecutive adult patients who underwent allo-HSCT at Mayo Clinic from January 2007 through July 2012. Multivariable Cox models were created to assess the relationship of SCC with two time-dependent voriconazole exposure variables: (i) history of voriconazole exposure (yes/no), and (ii) cumulative days of voriconazole use.

RESULTS

In our cohort of 381 allo-HSCT patients, SCC developed in 26 of 312 patients exposed to voriconazole (25 post-voriconazole) and in 1 of 69 patients who received alternative antifungal agent(s). Cumulative incidence of SCC was estimated to be 19% at 5 years post allo-transplant. Cumulative days of voriconazole use was found to be a risk factor for SCC, and this relationship persisted in a multivariable model using previously identified risk factors as covariates (hazard ratio 1.859 for each 180 days of use, P < 0.001).

CONCLUSION

This is the first study, to our knowledge, to identify cumulative days of voriconazole use as a risk factor for SCC development following allo-HSCT, and may help guide appropriate antifungal use in this patient population.

Voriconazole-associated phototoxic dermatoses and skin cancer

Voriconazole's antifungal spectrum, oral bioavailability, and proven efficacy in treatment of invasive mycoses have led to its widespread off-label use for antifungal prophylaxis. There is an increasing recognition that long-term voriconazole use is associated with accelerated sun-induced skin changes that include acute phototoxicity reactions, photoaging, actinic keratosis and esp. among immunocompromised patients, skin cancers. The mechanisms underlying these dermatologic adverse events are not clearly understood. Population-risks of long-term voriconazole use need to be prospectively investigated. This review aims to provide an in-depth assessment of published literature and highlight salient findings from retrospective studies and case series. A broad practical guideline for assessment and management of these patients is provided.