Issues Related to the Design and Interpretation of Clinical Trials of Salvage Therapy for Invasive Mold Infection

Acute Invasive Pulmonary Aspergillosis: Clinical Presentation and Treatment

Among all clinical manifestations of pulmonary aspergillosis, invasive pulmonary aspergillosis (IPA) is the most acute presentation. IPA is caused by Aspergillus hyphae invading the pulmonary tissue, causing either tracheobronchitis and/or bronchopneumonia. The degree of fungal invasion into the respiratory tissue can be seen as a spectrum, going from colonization to deep tissue penetration with angio-invasion, and largely depends on the host's immune status. Patients with prolonged, severe neutropenia and patients with graft-versus-host disease are at particularly high risk. However, IPA also occurs in other groups of immunocompromised and nonimmunocompromised patients, like solid organ transplant recipients or critically ill patients with severe viral disease. While a diagnosis of proven IPA is challenging and often warranted by safety and feasibility, physicians must rely on a combination of clinical, radiological, and mycological features to assess the likelihood for the presence of IPA. Triazoles are the first-choice regimen, and the choice of the drug should be made on an individual basis. Adjunctive therapy such as immunomodulatory treatment should also be taken into account. Despite an improving and evolving diagnostic and therapeutic armamentarium, the burden and mortality of IPA still remains high. This review aims to give a comprehensive and didactic overview of the current knowledge and best practices regarding the epidemiology, clinical presentation, diagnosis, and treatment of acute IPA.

Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.

Practice Guidelines for the Diagnosis and Management of Aspergillosis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Use of intravoxel incoherent motion diffusion-weighted MR imaging for assessment of treatment response to invasive fungal infection in the lung

OBJECTIVES

The purpose of this study was to determine whether intravoxel incoherent motion (IVIM) -derived parameters and apparent diffusion coefficient (ADC) could act as imaging biomarkers for predicting antifungal treatment response.

METHODS

Forty-six consecutive patients (mean age, 33.9 ± 13.0 y) with newly diagnosed invasive fungal infection (IFI) in the lung according to EORTC/MSG criteria were prospectively enrolled. All patients underwent diffusion-weighted magnetic resonance (MR) imaging at 3.0 T using 11 b values (0-1000 sec/mm²). ADC, pseudodiffusion coffiecient D*, perfusion fraction f, and the diffusion coefficient D were compared between patients with favourable (n=32) and unfavourable response (n=14).

RESULTS

f values were significantly lower in the unfavourable response group (12.6%±4.4%) than in the favourable response group (30.2%±8.6%) (Z=4.989, P<0.001). However, the ADC, D, and D* were not significantly different between the two groups (P>0.05). Receiver operating characteristic curve analyses showed f to be a significant predictor for differentiation, with a sensitivity of 93.8% and a specificity of 92.9%.

CONCLUSIONS

IVIM-MRI is potentially useful in the prediction of antifungal treatment response to patients with IFI in the lung. Our results indicate that a low perfusion fraction f may be a noninvasive imaging biomarker for unfavourable response.

KEY POINTS

• Recognition of IFI indicating clinical outcome is important for treatment decision-making. • IVIM can reflect diffusion and perfusion information of IFI lesions separately. • Perfusion characteristics of IFI lesions could help differentiate treatment response. • An initial low f may predict unfavourable response in IFI.

Consensus guidelines for the treatment of invasive mould infections in haematological malignancy and haemopoietic stem cell transplantation, 2014

Mould species represent the pathogens most commonly associated with invasive fungal disease in patients with haematological malignancies and patients of haemopoietic stem cell transplants. Invasive mould infections in these patient populations, particularly in the setting of neutropenia, are associated with high morbidity and mortality, and significantly increase the complexity of management. While Aspergillus species remain the most prevalent cause of invasive mould infections, Scedosporium and Fusarium species and the Mucormycetes continue to place a significant burden on the immunocompromised host. Evidence also suggests that infections caused by rare and emerging pathogens are increasing within the setting of broad-spectrum antifungal prophylaxis and improved survival times placing immunosuppressed patients at risk for longer. These guidelines present evidence-based recommendations for the antifungal management of common, rare and emerging mould infections in both adult and paediatric populations. Where relevant, the role of surgery, adjunctive therapy and immunotherapy is also discussed.

A novel scoring system to predict the incidence of invasive fungal disease in salvage chemotherapies for malignant lymphoma

The requirement of antifungal prophylaxis has not been established in the chemotherapies for malignant lymphoma. This study was conducted to explore the incidence of invasive fungal diseases (IFD) and their risk factors in patients receiving salvage therapies for malignant lymphoma. We retrospectively analyzed 177 consecutive patients who received these therapies (705 courses in total) at our institute. IFD were observed in 16 courses and the incidence was 2.3 %. A multivariate analysis showed that the factors associated with IFD were primary refractoriness (adjusted odds ratio (aOR), 4.22; 95 % confidence interval (CI), 1.38-13.0; p value = 0.012), two (aOR, 10.5, 95 % CI, 1.20-91.7; p = 0.033) or more (aOR, 26.2; 95 % CI, 3.27-210; p = 0.002) previous treatment lines, and the minimum neutrophil count during the therapies equal to or less than 500/μL (aOR, 9.69; 95 % CI, 1.25-74.9; p = 0.030). Using these factors, we created the IFD scoring model by assigning one point to each of primary refractoriness, two previous treatment lines and treatment that caused neutropenia (≤500/μL minimal neutrophil count) and two points to three or more previous treatment lines. The IFD incidence of lower risk group (IFD score <3) was 0.19 % and that of higher (IFD score ≥3) was 9.0 %. In conclusion, adequate prophylaxis for IFD might be required for patients with primary refractoriness, repeated therapies, or therapies which cause neutropenia. Furthermore, the IFD scoring model of this study underscores the need to account for disease and host factors in determining administration of adequate prophylaxis in salvage treatments for malignant lymphoma.

Highly variable plasma concentrations of voriconazole in pediatric hematopoietic stem cell transplantation patients

Invasive fungal infections are of great concern in pediatric hematopoietic stem cell transplantation (HSCT) recipients. Voriconazole is usually the drug of first choice for treating or preventing invasive aspergillosis. Optimum trough levels (C(trough)s) are between 1 and 5 mg/liter. It is unclear whether these levels are reached with currently advised pediatric dosing schedules. Between 2007 and 2011, 11 patients <2 years of age, 31 between 2 and 12 years, and 20 between 12 and 20 years were (prophylactically or therapeutically) treated with voriconazole in the HSCT unit of UMC Utrecht. For children <2 years of age, the dosage recommended for 2 to 12 years was used. In 34% of children who started with the recommended dose, an adequate C(trough) was reached irrespective of age or administration route. After therapeutic drug monitoring (TDM)-based dose adjustments, adequate C(trough)s were reached in 80% of the patients at median doses of 31.5 (age, <2 years), 16 (age, 2 to 12 years), and 9.4 mg/kg of body weight/day (age, >12 years) (P = 0.034). The intrapatient variability in C(trough) ranged between 1 and 238%. Voriconazole was discontinued in six patients due to toxicity. These patients had a median C(trough) of 0.5 mg/liter at the initial dose (ranging from 0.5 to 2.6 mg/liter), and a medium maximal concentration of 4 mg/liter was reached. Inter- and intrapatient variability is a major concern in voriconazole treatment and necessitates therapeutic drug monitoring of dosing, especially in young children.

Therapeutic drug monitoring of voriconazole in children

Voriconazole is an extended-spectrum triazole antifungal with activity against a wide variety of pathogens, including Aspergillus, Candida, Cryptococcus neoformans, Fusarium, and Scedosporium. It exerts its antifungal activity by blocking the synthesis of fungal cell membranes and is considered the first-line treatment for invasive aspergillosis. Because the pharmacokinetics of voriconazole can demonstrate considerable variability, it has been suggested that monitoring plasma levels of voriconazole may play an important role in optimizing the efficacy and safety of the drug in complex patients like those at risk of or who have invasive aspergillosis. In this article, we review the criteria for therapeutic drug monitoring and assess the evidence for using plasma voriconazole concentrations to individualize doses in children.

Assessing responses to treatment of opportunistic mycoses and salvage strategies

Invasive fungal disease (IFD) in immunocompromised patients remains a major cause of morbidity and mortality and there is a pressing need for studies of novel antifungal agents and strategies to improve outcomes. Trial design details often determine not only the appropriate interpretation of the results, but also their translation into clinical practice. However, the conduct of IFD clinical trials remains challenging due to the rarity of IFD, heterogeneity of underlying diseases, and the lack of clear and standardized response criteria. Response assessments are influenced by host, underlying disease and treatment factors as well as eligibility criteria. In addition, the criteria used to assess response, when response is assessed and the type of antifungal therapy under study can impact response evaluations. This article will discuss recent trials of primary, salvage, empiric, and prophylactic antifungal therapy with specific attention to the design of these antifungal therapy trials and how their designs influence their interpretation. The potential role of surrogate markers, such as the galactomannan index, fungal deoxyribonucleic acid polymerase chain reaction assay, and (18F) fluorodeoxyglucose positron emission tomography scans in establishing the early diagnosis of IFD, as well as enhancing the ability to assess outcomes to antifungal therapy, and thereby the optimal duration of antifungal therapy, will be discussed.

Neutropenic fever syndromes in patients undergoing cytotoxic therapy for acute leukemia and myelodysplastic syndromes

Fever represents the major surrogate of infection in neutropenic cancer patients. A number of neutropenic fever syndromes have been recognized, the causes and significance of which will vary depending upon the clinical context. First neutropenic fever syndromes are typically of bacterial origin, the character of which may be influenced by whether antibacterial chemoprophylaxis has been administered. Persistent neutropenic fevers are documented during the empirical systemic antibacterial therapy for the first neutropenic fever, the cause of which is likely outside the spectrum of activity of the initial therapy. Recrudescent neutropenic fevers, defined by the appearance of a new fever after defervescence of the first fever, are often a function of invasive fungal infection or gram-positive infections outside the spectrum of the initial empirical antibacterial regimen. The myeloid reconstitution syndrome occurs in parallel with neutrophil recovery from aplasia and may not necessarily represent new infection. Recognition of these patterns can help the clinician make better clinical judgments and management plans.

Defining responses to therapy and study outcomes in clinical trials of invasive fungal diseases: Mycoses Study Group and European Organization for Research and Treatment of Cancer consensus criteria

Invasive fungal diseases (IFDs) have become major causes of morbidity and mortality among highly immunocompromised patients. Authoritative consensus criteria to diagnose IFD have been useful in establishing eligibility criteria for antifungal trials. There is an important need for generation of consensus definitions of outcomes of IFD that will form a standard for evaluating treatment success and failure in clinical trials. Therefore, an expert international panel consisting of the Mycoses Study Group and the European Organization for Research and Treatment of Cancer was convened to propose guidelines for assessing treatment responses in clinical trials of IFDs and for defining study outcomes. Major fungal diseases that are discussed include invasive disease due to Candida species, Aspergillus species and other molds, Cryptococcus neoformans, Histoplasma capsulatum, and Coccidioides immitis. We also discuss potential pitfalls in assessing outcome, such as conflicting clinical, radiological, and/or mycological data and gaps in knowledge.

Monitoring trough concentration of voriconazole is important to ensure successful antifungal therapy and to avoid hepatic damage in patients with hematological disorders

We investigated the role of therapeutic dose monitoring (TDM) in the treatment of fungal infections with voriconazole through 49 analyses of 34 patients who received treatment for hematologic diseases. Voriconazole concentration was highly variable among patients regardless of renal, liver functions, or age, and the effect of dose enhancement was not constant. This indicates the difficulty of predicting voriconazole concentration without TDM. We evaluated the outcome with the composite assessment system where patients were assumed non-responders when they failed to show improvement in at least 2 of the following 3 criteria: clinical, radiologic, and mycologic. We showed that concentration-response relationship depended on the status of underlying hematologic diseases; this relationship was observed only in cases without refractory hematologic diseases, but not in those with refractory diseases. In the former group, cases with >2 mg/L of concentration were associated with good response to voriconazole. On the other hand, elevation of hepatic enzyme was frequently observed when voriconazole concentration was >6 mg/L. From these results, we concluded that TDM should be executed and targeted to 2-6 mg/L to improve efficacy and to avoid side effects.

Recommendations for the treatment of established fungal infections

Evidence-based guidelines for the treatment of established fungal infections in the adult haematology/oncology setting were developed by a national consensus working group representing clinicians, pharmacists and microbiologists. These updated guidelines replace the previous guidelines published in the Internal Medicine Journal by Slavin et al. in 2004. The guidelines are pathogen-specific and cover the treatment of the most common fungal infections including candidiasis, aspergillosis, cryptococcosis, zygomycosis, fusariosis, scedosporiosis, and dermatophytosis. Recommendations are provided for management of refractory disease or salvage therapies, and special sites of infections such as the cerebral nervous system and the eye. Because of the widespread use newer broad-spectrum triazoles in prophylaxis and empiric therapy, these guidelines should be implemented in concert with the updated prophylaxis and empiric therapy guidelines published by this group.

Voriconazole therapeutic drug monitoring in patients with invasive mycoses improves efficacy and safety outcomes

BACKGROUND

Voriconazole is the therapy of choice for aspergillosis and a new treatment option for candidiasis. Liver disease, age, genetic polymorphism of the cytochrome CYP2C19, and comedications influence voriconazole metabolism. Large variations in voriconazole pharmacokinetics may be associated with decreased efficacy or with toxicity.

METHODS

This study was conducted to assess the utility of measuring voriconazole blood levels with individualized dose adjustments.

RESULTS

A total of 181 measurements with high-pressure liquid chromatography were performed during 2388 treatment days in 52 patients. A large variability in voriconazole trough blood levels was observed, ranging from <or=1 mg/L (the minimum inhibitory concentration at which, for most fungal pathogens, 90% of isolates are susceptible) in 25% of cases to >5.5 mg/L (a level possibly associated with toxicity) in 31% of cases. Lack of response to therapy was more frequent in patients with voriconazole levels <or=1 mg/L (6 [46%] of 13 patients, including 5 patients with aspergillosis, 4 of whom were treated orally with a median dosage of 6 mg/kg per day) than in those with voriconazole levels >1 mg/L (15 [12%] of 39 patients; P=.02). Blood levels >1 mg/L were reached after increasing the voriconazole dosage, with complete resolution of infection in all 6 cases. Among 16 patients with voriconazole trough blood levels >5.5 mg/L, 5 patients (31%) presented with an encephalopathy, including 4 patients who were treated intravenously with a median voriconazole dosage of 8 mg/kg per day, whereas none of the patients with levels <or=5.5 mg/L presented with neurological toxicity (P=.002). Comedication with omeprazole possibly contributed to voriconazole accumulation in 4 patients. In all cases, discontinuation of therapy resulted in prompt and complete neurological recovery.

CONCLUSIONS

Voriconazole therapeutic drug monitoring improves the efficacy and safety of therapy in severely ill patients with invasive mycoses.

Combination antifungals: an update

Invasive fungal infections are an important cause of morbidity and mortality in specific patient populations. There has been an impressive increase in the antifungal armamentarium, yet optimal therapies for many invasive fungal infections remain unknown. Genomic sequencing of a number of pathogenic fungi will pave the way to discovering additional newer targets for antifungal drug design. These new discoveries, plus the existing repertoire of antifungal agents, create the need to effectively model single and combination antifungal agents. Future therapies may also include the use of cell-stress pathway inhibitors in combination with existing antifungal agents. This review focuses on combination antifungal therapy against Cryptococcus neoformans, Candida and Aspergillus species. Combination therapy is only supported by randomized clinical trials for cryptococcal meningitis. We review data from in vitro and animal model studies as well as insights from clinical trials to discuss current thoughts and highlight the gaps in our knowledge surrounding combination antifungal therapy.

Increasing the efficiency of clinical trials of antimicrobials: the scientific basis of substantial evidence of effectiveness of drugs

In the United States, drug sponsors must obtain approval from the US Food and Drug Administration before licensure and widespread clinical use of drugs. In this article, I discuss the definition and history of the regulatory requirement for "substantial evidence" of effectiveness from "adequate and well-controlled" clinical trials of drugs. These requirements apply to antimicrobials as they do to other therapeutic drug classes, and they may be even more important in their application to antimicrobials, given issues of antimicrobial resistance. I will discuss the evidence requirements, using examples from clinical trials in diseases such as acute otitis media, acute bacterial sinusitis, and acute exacerbations of chronic bronchitis. Examination of the principles of substantial evidence also points to opportunities to improve the efficiency of confirmatory clinical trials of antimicrobials to obtain more clinically relevant and useful information without increasing the uncertainty regarding the safety and efficacy of these drugs.

Posaconazole Therapy for Chronic Refractory Coccidioidomycosis

BACKGROUND

Coccidioides infections often result in chronic relapsing disease that presents a challenge to the currently available therapy. Posaconazole, an oral extended-spectrum triazole agent, has been shown in vitro and in vivo to have potent activity against this fungus.

METHODS

An open-label multinational study of posaconazole, 800 mg/d, administered in divided doses for the treatment of invasive fungal infection that has been refractory to previous therapy was conducted. The data were reviewed by an independent data review committee (DRC). Fifteen patients met the criteria for proven coccidioidal infection and disease refractory to previous therapy. Success was a complete or partial response; nonsuccess was stable disease, lack of response to therapy, or undetermined response.

RESULTS

The sites of coccidioidal infection were pulmonary (seven patients) and disseminated (eight patients). Patients were refractory to previous therapy (including amphotericin B with or without an azole) for a median duration of 306 days. At the end of treatment (posaconazole treatment duration, 34 to 365 days), therapy for 11 of 15 patients (73%) was considered to be successful by the DRC. Four responses were complete and seven were partial; these included five patients with pulmonary sites and six patients with disseminated sites. In responders, improvement was seen within months of the initiation of therapy. Five patients received therapy for >or= 12 months. The side effects were minimal.

CONCLUSIONS

Therapy for coccidioidomycosis remains a clinical challenge, especially when patients have not responded to therapy with drugs that were recommended in treatment guidelines. The success rate (73%) achieved in this case series suggests that oral posaconazole should be considered as an important agent for the treatment of refractory coccidioidomycosis.

Serum Aspergillus galactomannan antigen values strongly correlate with outcome of invasive aspergillosis

BACKGROUND

Determining the outcome of patients with aspergillosis can be particularly difficult because patients with aspergillosis are at risk for other conditions that mimic this infection. Galactomannan is an Aspergillus-specific antigen released during invasive aspergillosis and is detected by the quantitative serum galactomannan index (GMI) test.

METHODS

Using a kappa correlation coefficient test (KCC), the strength of correlation was determined between GMI and survival outcome of aspergillosis among 56 adults with hematologic cancer (90% had myeloma) who underwent serial GMI monitoring until hospital discharge or death.

RESULTS

All 56 patients received antineoplastic therapy (myeloablative followed by stem cell transplantation [autologous in 21 patients and allogeneic in 3 patients] or nonmyeloablative therapy [32 patients]). The overall correlation between survival outcome and GMI was excellent (KCC = 0.8609; 95% confidence interval [95% CI], 0.7093-1.000 [P < .0001]) and was comparable among neutropenic and nonneutropenic patients (KCC = 0.8271; 95% CI, 0.6407-1.000 [P < .0001] and KCC = 1.0; 95% CI, 1-1 [P = .0083], respectively).

CONCLUSIONS

The survival outcome of patients with aspergillosis strongly correlated with serum GMI. These findings have important implications for patient care and clinical trials of mold-active antifungal agents.

Immune reconstitution inflammatory syndrome in cancer patients with pulmonary aspergillosis recovering from neutropenia: Proof of principle, description, and clinical and research implications

BACKGROUND

Assessing the outcome of patients with invasive pulmonary aspergillosis by using conventional criteria is difficult, particularly when clinical and radiologic worsening coincides with neutrophil recovery. Usually, it is assumed that this deterioration is related to progressive aspergillosis, prompting changes in patient management. However, its temporal relation with neutrophil recovery suggests that it may be caused by an immune reconstitution syndrome (IRIS). Galactomannan is an Aspergillus-specific polysaccharide that is released during aspergillosis and is detected by the serum galactomannan test, which has been approved by the United States Food and Drug Administration for the diagnosis of invasive aspergillosis. In this study, the authors used sequential galactomannan testing to distinguish IRIS responses from progressive aspergillosis.

METHODS

From April 2001 to December 2006, patients with hematologic malignancies underwent galactomannan screening during periods when they were at risk. The clinical and laboratory findings from patients who had >or=2 consecutive positive galactomannan assays (optical density, >or=0.5) were reviewed.

RESULTS

Nineteen neutropenic patients with aspergillosis developed clinical and radiologic pulmonary deterioration during neutrophil recovery. Deterioration coincided with microbiologic response, as documented by rapid normalization of serum galactomannan, and, in 16 patients, was followed by complete clinical response and survival at 3 months, although there were no changes in antifungal therapy. The 3 patients who died during the first month had no evidence of aspergillosis at autopsy examination.

CONCLUSIONS

The authors propose that IRIS was responsible for the current findings and provide a definition for the syndrome. They also recommend serial galactomannan testing to guide aspergillosis management. Declining galactomannan values imply IRIS with an aspergillus response and obviate the need for invasive procedures and alternative antifungal therapies, whereas persistent galactomannan elevation indicates progressive aspergillosis and requires prompt treatment modification.