Cyclophosphamide metabolism is affected by azole antifungals

Expanding the scope of the infectious diseases pharmacist in HCT: Beyond antimicrobial stewardship

BACKGROUND

Infectious disease (ID) pharmacists and antimicrobial stewardship (AMS) programs are integral to the infection management of hematopoietic cell transplant (HCT) recipients demonstrating effective implementation of clinical pathways, de-escalation of empirical antibiotics for febrile neutropenia (FN), allergy assessments, and use of rapid diagnostic testing. The HCT procedure is complex, dynamic, and a high risk for infectious complications. Therefore, there is an important role for an ID and AMS pharmacist to collaborate with the primary treating team, with ongoing care, involving the optimal individual patient prophylactic, pre-emptive and treatment management of infections in this high-risk population.

CONCLUSION

This review highlights key factors for consideration of ID/AMS Pharmacists in relation to HCT, including important aspects in the evaluation of infection risk prior to transplant, risk from donor sources, length of, and changes in immunosuppression, and potential drug-drug interactions from other essential supportive care therapies.

Successful Treatment of Paecilomyces variotii Pneumonia and Lupus Nephritis With Posaconazole-Cyclophosphamide Co-administration Without Drug Interaction-Induced Toxicity

Paecilomyces variotii is an opportunistic mold that causes pulmonary infections in immunosuppressed humans that are often treated with triazole therapy. Lupus nephritis is a major cause of progressive kidney disease in patients with systemic lupus erythematosus, often requiring cyclophosphamide-based therapies. Triazole-cyclophosphamide co-administration is challenging as triazoles increase cyclophosphamide concentrations, which can worsen cyclophosphamide toxicity. We describe herein a patient with Paecilomyces variotii pneumonia and concomitant lupus nephritis who was successfully treated with posaconazole and echinocandin-bridged interruptions to allow for cyclophosphamide therapy. This regimen was well-tolerated without cyclophosphamide toxicity and achieved improvements in both fungal pneumonia and renal function.

A review of prophylactic regimens to prevent invasive fungal infections in hematology patients undergoing chemotherapy or stem cell transplantation

INTRODUCTION

The recent introduction of targeted therapies, including monoclonal antibodies, tyrosine-kinase inhibitors, and immunotherapies has improved the cure rate of hematologic patients. The implication of personalized treatment on primary antifungal prophylaxis will be discussed.

AREAS COVERED

We reviewed the literature for clinical trials reporting the rate of invasive fungal infections during targeted and cellular therapies and stem cell transplant, and the most recent international guidelines for primary antifungal prophylaxis.

EXPERT OPINION

As the use of personalized therapies is growing, the risk of invasive fungal infection has emerged in various clinical settings. Therefore, it is possible that the use of mold-active antifungal prophylaxis would spread in the next years and the risk of breakthrough infections would increase. The introduction of new antifungal agents in the clinical armamentarium is expected to reduce clinical unmet needs concerning the management of primary antifungal prophylaxis and improve outcome of patients.

Precision Oncology by Point-of-Care Therapeutic Drug Monitoring and Dosage Adjustment of Conventional Cytotoxic Chemotherapies: A Perspective

Therapeutic drug monitoring (TDM) of conventional cytotoxic chemotherapies is strongly supported yet poorly implemented in daily practice in hospitals. Analytical methods for the quantification of cytotoxic drugs are instead widely presented in the scientific literature, while the use of these therapeutics is expected to keep going for longer. There are two main issues hindering the implementation of TDM: turnaround time, which is incompatible with the dosage profiles of these drugs, and exposure surrogate marker, namely total area under the curve (AUC). Therefore, this perspective article aims to define the adjustment needed from current to efficient TDM practice for cytotoxics, namely point-of-care (POC) TDM. For real-time dose adjustment, which is required for chemotherapies, such POC TDM is only achievable with analytical methods that match the sensitivity and selectivity of current methods, such as chromatography, as well as model-informed precision dosing platforms to assist the oncologist with dose fine-tuning based on quantification results and targeted intervals.

Systemic Antifungal Therapy for Invasive Pulmonary Infections

Antifungal therapy for pulmonary fungal diseases is in a state of flux. Amphotericin B, the time-honored standard of care for many years, has been replaced by agents demonstrating superior efficacy and safety, including extended-spectrum triazoles and liposomal amphotericin B. Voriconazole, which became the treatment of choice for most pulmonary mold diseases, has been compared with posaconazole and itraconazole, both of which have shown clinical efficacy similar to that of voriconazole, with fewer adverse events. With the worldwide expansion of azole-resistant Aspergillus fumigatus and infections with intrinsically resistant non-Aspergillus molds, the need for newer antifungals with novel mechanisms of action becomes ever more pressing.

Acute Lymphoblastic Leukemia and Invasive Mold Infections: A Challenging Field

Acute lymphoblastic leukemia (ALL) patients comprise a highly immunocompromised group due to factors associated either with the treatment or the disease itself. Invasive mold infections (IMIs) are considered to be responsible for higher morbidity and mortality rates in patients with hematologic malignancies, including ALL. Defining the exact incidence of IMIs in ALL patients has been rather complicated. The available literature data report a highly variable incidence of IMIs, ranging from 2.2% to 15.4%. Although predisposing factors for IMIs in the setting of ALL are ill-defined, retrospective studies have indicated that a longer duration of neutropenia, treatment with high-dose corticosteroids, and a lack of antimold prophylaxis are associated with an increased risk of IMIs. Additionally, the influence of novel ALL treatments on the susceptibility to fungal infections remains obscure; however, initial data suggest that these treatments may induce prolonged neutropenia and thus an increased risk of IMIs. Administering primary antimold prophylaxis in these patients has been challenging since incorporating azole antifungal agents is troublesome, considering the drug-to-drug interactions (DDIs) and increased toxicity that may occur when these agents are coadministered with vincristine, a fundamental component of ALL chemotherapy regimens. Isavuconazole, along with several novel antifungal agents such as rezafungin, olorofim, and manogepix, may be appealing as primary antimold prophylaxis, given their broad-spectrum activity and less severe DDI potential. However, their use in ALL patients needs to be investigated through more clinical trials. In summary, this review outlines the epidemiology of IMI and the use of antifungal prophylaxis in ALL patients.

Cyclophosphamide-induced cardiotoxicity at conditioning for allogeneic hematopoietic stem cell transplantation would occur among the patients treated with 120 mg/kg or less

Cyclophosphamide (CY)-induced cardiotoxicity involves rare lethal complications. We previously reported the cardiac events of 811 allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients; 12 out of 811 recipients (1.5%) developed fatal heart failure. The mortality rate was also very high (91.6%, 11/12). CY dose (200 mg/kg or more) was reported as the independent risk factor. The main disease in patients treated with 200 mg/kg or more of CY was severe aplastic anemia (AA). Therefore, we reduced the dose of CY during conditioning for AA (from 200 to 100 mg/kg), and then we analyzed the clinical features of 294 patients who received a total dose of at least 100 mg/kg of CY. We also compared the clinical features between the current study and our previous study. The proportion of patients treated with at least 200 mg/kg of CY was reduced from 4.2% to 0%. However, CY-induced heart failure occurred in four of the 294 patients (1.4%), which was similar to the finding reported in our previous study (1.5%). Two of these four patients received a post-transplant CY (PTCy) regimen (CY 100 mg/kg). All four patients were treated in the cardiac intensive care unit (C-ICU), and two patients survived. In summary, even the CY dose of 120 mg/kg or less would cause cardiotoxicity. We should also carefully monitor patients treated with PTCy, considering the possibility of CY-induced cardiotoxicity. Early diagnosis and ICU management have contributed to improved outcomes.

Duration of sweat cyclophosphamide excretion in patients undergoing a conditioning regimen of high-dose cyclophosphamide for hematopoietic stem-cell transplantation

PURPOSE

To investigate the duration of cyclophosphamide (CPA) excretion in the sweat after administration when receiving high-dose CPA therapy as a conditioning regimen for hematopoietic stem-cell transplantation (HSCT).

METHODS

Shirts and pillowcases samples (changed once a day) from 12 patients, categorized as groups 1 (n  =  6), 2 (n = 4), and 3 (n  =  2), receiving high-dose CPA therapy were collected, sealed, stored at 4°C, and mailed to an analytical facility for CPA estimation using LC-MS/MS. CPA was administered intravenously at a dose of 60 mg/kg on days 1, 2 (closed-system delivery for group 3), and samples were collected during days 1-4 (groups 1,3) or days 1-9 (group 2).

RESULTS

CPA was detected in all 126 shirts and pillowcases. In 9 patients, excluding 1 patient who had fever during the study period and group 3 patients, the mean (range) rate of CPA excretion in sweat was 0.03% (0.01-0.12%). The mean CPA excretion in 9 patients adjusted for body weight was 19.9 μg/kg on day 1 and 0.3 μg/kg on day 4.

CONCLUSIONS

This study showed that CPA was excreted for an extended duration in the patient's sweat, receiving a high-dose CPA therapy as a conditioning regimen against HSCT.

Evaluation for pharmacokinetic exposure of cytotoxic anticancer drugs in elderly patients receiving (R-)CHOP therapy

(R-)miniCHOP therapy, which delivers approximately half-doses of the (R-)CHOP regimen, has shown efficacy and safety in patients who are more than 80 years old. This study aimed to compare the area under the plasma concentration–time curves (AUCs) of vincristine (VCR), doxorubicin (DXR), and cyclophosphamide (CPA) between (R-)CHOP and (R-)miniCHOP regimens. The AUCs were compared between patients aged 65–79 years receiving (R-)CHOP therapy and those aged 80 years and older receiving (R-)miniCHOP therapy. Age was not an independent variable for predicting the dose-adjusted AUCs (AUC/Ds) of cytotoxic anticancer drugs. The median AUCs of DXR and CPA were significantly smaller in the (R-)miniCHOP group than in the (R-)CHOP group (168.7 vs. 257.9 ng h/mL, P = 0.003, and 219.9 vs. 301.7 µg h/mL, P = 0.020, respectively). The median AUCs of VCR showed the same trend but the difference was not significant (24.83 vs. 34.85 ng h/mL, P = 0.135). It is possible that the AUCs of VCR, DXR, and CPA in patients aged 80 years and older receiving (R-)miniCHOP therapy may be lower than those in patients 65–79 years old receiving (R-)CHOP therapy.

A Guidance for Concomitant Drug Reconciliation Prior to Allogeneic Hematopoietic Cell Transplantation in Children and Young Adults

Pediatric diseases treated by allogeneic hematopoietic stem cell transplantation (alloHCT) are complex and associated with significant comorbidities and medication requirements that can complicate the transplant process. It is critical to reconcile pre-transplant concomitant medications (pcon-meds) in the weeks prior to alloHCT and to consider the potential for pcon-meds to cause harmful drug-drug interactions (DDIs) or overlapping toxicities with conditioning agents. In this perspective, we describe a systematic process to review pcon-meds and determine the drug modifications needed to avoid DDIs with conditioning regimens. We provide an extensive appendix with timelines for discontinuation or modification of common pcon-meds that patients are taking when presenting to the HCT medical team. The timelines are based on the pharmacokinetic (PK) properties of both the pcon-meds and the planned conditioning medications, as well as anticipated DDIs. They also account for the ages seen at pediatric transplant centers (0-30 years old). Common scenarios, such as when pcon-med discontinuation is not an option, are discussed. Since alloHCT patients are often dependent upon psychiatric medications with problematic DDIs, a table of alternative, non-interacting psychiatric medications is also presented. The appendix provides details regarding how to adjust pcon-meds prior to the start of chemotherapy for children and young adults undergoing alloHCT, however patient-specific circumstances always need to be taken into account. Careful attentiveness to pcon-meds at the time the decision is made to pursue transplant will result in more consistent HCT outcomes, with lower toxicity and increased efficacy of conditioning agents.

Invasive fungal diseases in patients with new diagnosed acute lymphoblastic leukaemia

BACKGROUND

Patients with acute leukaemia have a high incidence of fungal infections. This has primarily been shown in acute myeloid leukaemia and is different for acute lymphoblastic leukaemia. Until now no benefit of mould active prophylaxis has been demonstrated in the latter population.

METHODS

In this retrospective single-centre study, we analysed the incidence, clinical relevance, and outcome of invasive fungal diseases (IFD) as well as the impact of antifungal prophylaxis for the first 100 days following the primary diagnosis of acute lymphoblastic leukaemia.

RESULTS

In 58 patients a high rate of proven, probable, and possible fungal infections could be demonstrated with a 3.4%, 8.6%, and 17.2% likelihood, respectively. The incidence might be even higher, as nearly 40% of all patients had no prolonged neutropenia for more than 10 days, excluding those from the European Organization of Research and Treatment of cancer and the Mycoses Study Group criteria for probable invasive fungal disease. The diagnosed fungal diseases had an impact on the duration of hospitalisation, which was 13 days longer for patients with proven/probable IFD compared to patients with no signs of fungal infection. Use of antifungal prophylaxis did not significantly affect the risk of fungal infection.

CONCLUSION

Patients with acute lymphoblastic leukaemia are at high risk of acquiring an invasive fungal disease. Appropriate criteria to define fungal infections, especially in this population, and strategies to reduce the risk of infection, including antifungal prophylaxis, need to be further evaluated.

The Influence of Different Triazole Antifungal Agents on the Pharmacokinetics of Cyclophosphamide

Background: Cyclophosphamide is one of the most important chemotherapeutic drugs. Known as a widely accepted treatment strategy, chemotherapy may damage the immune function of cancer patients; as a result, invasive fungal infections (IFIs) occur. Triazole antifungal agents are the most acceptable drugs for IFI treatment, especially those infections caused by chemotherapy. Objective: We aimed to investigate the effects of different triazole antifungal drugs, including fluconazole, itraconazole, and ketoconazole, on the pharmacokinetics (PK) of cyclophosphamide. In addition, we also characterize the potential drug-drug interactions (DDIs) between cyclophosphamide and various triazole antifungal drugs. Methods: The necessary pharmacokinetic parameters and physicochemical data were obtained from published studies. Physiologically based pharmacokinetic (PBPK) models were developed and validated in virtual subjects using Simcyp software. The validated PBPK models were used to evaluate potential DDIs between cyclophosphamide and different triazole antifungal agents in cancer patients. Triazole antifungal agents were simulated by oral administration, whereas cyclophosphamide was simulated by intravenous administration. Results: Simulated plasma concentration-time curves of fluconazole, itraconazole, ketoconazole, and cyclophosphamide were in good consistency with the observed profiles. Our results suggested that the pharmacokinetic parameters of cyclophosphamide were increased by various extents when coadministered with different triazole antifungals. The area under the plasma concentration-time curve of cyclophosphamide was increased when combined with fluconazole, itraconazole, or ketoconazole. Conclusions and Relevance: Ketoconazole had the greatest effect on the PK of cyclophosphamide among the 3 triazole antifungals. Our study provides clues that the toxicity and adverse drug reactions that are associated with cyclophosphamide should be closely monitored when coadministered with ketoconazole.

Invasive Aspergillosis in Pediatric Leukemia Patients: Prevention and Treatment

The purpose of this article is to review and update the strategies for prevention and treatment of invasive aspergillosis (IA) in pediatric patients with leukemia and in patients with hematopoietic stem cell transplantation. The major risk factors associated with IA will be described since their recognition constitutes the first step of prevention. The latter is further analyzed into chemoprophylaxis and non-pharmacologic approaches. Triazoles are the mainstay of anti-fungal prophylaxis while the other measures revolve around reducing exposure to mold spores. Three levels of treatment have been identified: (a) empiric, (b) pre-emptive, and (c) targeted treatment. Empiric is initiated in febrile neutropenic patients and uses mainly caspofungin and liposomal amphotericin B (LAMB). Pre-emptive is a diagnostic driven approach attempting to reduce unnecessary use of anti-fungals. Treatment targeted at proven or probable IA is age-dependent, with voriconazole and LAMB being the cornerstones in >2yrs and <2yrs age groups, respectively.

Drug-drug interactions in patients receiving hematopoietic stem cell transplantation

INTRODUCTION

Recipients of hematopoietic stem cell transplantation (HSCT) are exposed to numerous drugs in both pre- and post-transplantation period, which creates an opportunity for drug-drug interactions (DDIs); if clinically relevant DDIs happen, the risk of adverse treatment outcomes is increased. Areas covered: This review is focused on DDIs in recipients of HSCT that were observed and published as clinical trials, case series or case reports. Relevant publications were found by the systematic search of the following online databases: MEDLINE, SCOPUS, EBSCO, and SCINDEX. Expert opinion: The most important DDIs involve cytostatic or immunosuppressant drug on one side, and antimicrobial drugs on the other. The majority of clinically relevant interactions have pharmacokinetic character, involving drug metabolizing enzymes in the liver. Antifungal azoles inhibit metabolism of many cytostatic and immunosuppressant drugs at cytochromes and increase their plasma concentrations. Macrolide antibiotics and fluoroqunolones should be avoided in HSCT recipients, as they have much larger potential for DDIs than other antibiotic groups. HSCT recipients increasingly receive new immunomodulating drugs, and further observational studies are needed to reveal unsuspected DDIs with clinical relevance.

Invasive Aspergillosis in Children: Update on Current Guidelines

Invasive aspergillosis (IA) is an important cause of infectious morbidity and mortality in immunocompromised paediatric patients. Despite improvements in diagnosis, prevention, and treatment, IA is still associated with high mortality rates. To address this issue, several international societies and organisations have proposed guidelines for the management of IA in the paediatric population. In this article, we review current recommendations of the Infectious Diseases Society of America, the European Conference on Infection in Leukaemia and the European Society of Clinical Microbiology and Infectious Diseases for the management and prevention of IA in children.

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.

Echinocandin prophylaxis in patients undergoing haematopoietic cell transplantation and other treatments for haematological malignancies

Antifungal prophylaxis is the standard of care for patients undergoing intensive chemotherapy for haematological malignancy or haematopoietic cell transplantation (HCT). Prophylaxis with azoles reduces invasive fungal infections and may reduce mortality. However, breakthrough infections still occur, and the use of azoles is sometimes complicated by pharmacokinetic variability, drug interactions, adverse events and other issues. Echinocandins are highly active against Candida species, including some organisms resistant to azoles, and have some clinical activity against Aspergillus species as well. Although currently approved echinocandins require daily intravenous administration, the drugs have a favourable safety profile and more predictable pharmacokinetics than mould-active azoles. Clinical data support the efficacy and safety of echinocandins for antifungal prophylaxis in haematology and HCT patients, though data are less robust than for azoles. Notably, sparse evidence exists supporting the use of echinocandins as antifungal prophylaxis for patients with significant graft-versus-host disease (GvHD) after HCT. Two drugs that target (1,3)-β-d-glucan are in development, including an oral glucan synthase inhibitor and an echinocandin with unique pharmacokinetics permitting subcutaneous and weekly administration. Echinocandins are a reasonable alternative to azoles and other agents for antifungal prophylaxis in patients undergoing intensive chemotherapy for haematological malignancy or those receiving HCT, excluding those with significant GvHD.

An update on the safety and interactions of antifungal drugs in stem cell transplant recipients

INTRODUCTION

Invasive fungal diseases (IFDs) are a major cause of morbidity and mortality in patients undergoing allogeneic hematopoietic stem cell transplant (HSCT). Improvement in the management of IFDs have been achieved with the availability of new effective and safe antifungal drugs, however, many of these newer treatments have some limitations in their variable toxicity and unique predisposition for pharmacokinetic drug-drug interactions. Areas covered: This article is an update of a previous review published in this journal evaluating the safety profile of the antifungal drugs. Interesting new features include the availability of the new drug isavuconazole and the new tablet and intravenous formulations of posaconazole. Different dosages and new ways of administration of liposomal Amphotericin B (L-AmB) and echinocandins may be considered in the HSCT practice. Expert opinion: Nephrotoxicity continues to be a clinically relevant and frequent side effect of L-AmB which may cause a reduced clearance of other renally eliminated drugs frequently used in HSCT patients. Echinocandins are favorable therapeutic options in view of their low toxicity and uncommon drug-drug interactions. Important limitations of triazoles are represented by hepatic toxicity and certain side effects particularly after prolonged treatments. The new triazole isavuconazole and the new tablet formulation of posaconazole will be probably increasingly used in the HSCT setting not only due to their efficacy but in particular for their interesting toxicity profile and pharmacokinetic characteristics. The knowledge of these pharmacological findings is crucial in the daily care of allogeneic HSCT patients.

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.

Antifungal agents and liver toxicity: a complex interaction

INTRODUCTION

The number of antifungal agents has sharply increased in recent decades. Antifungals differ in their spectrum of activity, pharmacokinetic/pharmacodynamic properties, dosing, safety-profiles and costs. Risk of developing antifungal associated hepatotoxicity is multifactorial and is influenced by pre-existing liver disease, chemical properties of the drug, patient demographics, comorbidities, drug-drug interactions, environmental and genetic factors. Antifungal related liver injury typically manifests as elevations in serum aminotransferase levels, although the clinical significance of these biochemical alterations is not always clear. Incidence rates of hepatotoxicity induced by antifungal therapy range widely, occurring most frequently in patients treated with azole antifungals for documented fungal infections.

AREAS COVERED

This review provides an update regarding the hepatotoxicity profiles of the modern systemic antifungals used in treatment of invasive fungal infections. Expert commentary: Understanding the likelihood and pattern of hepatotoxicity for all suspected drugs can aid the clinician in early detection of liver injury allowing for intervention and potential mitigation of liver damage. Therapeutic drug monitoring is emerging as a potential tool to assess risk for hepatotoxicity.

Vulvovaginal candidosis: contemporary challenges and the future of prophylactic and therapeutic approaches

Vulvovaginal candidosis (VVC) is a common gynaecological disorder that is delineated by the inflammation of vaginal wall and it is caused by the opportunistic fungal pathogen Candida species. In fact, three out of every four women will experience at least one occasion of VVC during some point in their lives. Although uncomplicated VVC is relatively harmless, the complicated VVC such as recurrent attack often creates restlessness and depression in the patients, thus greatly affects their quality of life. Managements of VVC are usually associated with the use of antimycotic suppositories, topical cream or oral agents. These antimycotic agents are either available over-the-counter or prescribed by the clinicians. In recent decades, the rise of clinical challenges such as the increased prevalence of resistant Candida strains, recurrent VVC infection and adverse effects of multidrug interactions have necessitated the development of novel therapeutic or prophylactic options to combat the complicated VVC in the future. In this review, we discuss the current antimycotic treatments available for Candida vaginitis and the problems that exist in these seemingly effective treatments. Besides, we attempt to contemplate some of the future and prospective strategies surrounding the development of alternative therapeutic and prophylactic options in treating and preventing complicated VVC respectively.

Consensus guidelines for optimising antifungal drug delivery and monitoring to avoid toxicity and improve outcomes in patients with haematological malignancy, 2014

Antifungal agents may be associated with significant toxicity or drug interactions leading to sub-therapeutic antifungal drug concentrations and poorer clinical outcomes for patients with haematological malignancy. These risks may be minimised by clinical assessment, laboratory monitoring, avoidance of particular drug combinations and dose modification. Specific measures, such as the optimal timing of oral drug administration in relation to meals, use of pre-hydration and electrolyte supplementation may also be required. Therapeutic drug monitoring (TDM) of antifungal agents is warranted, especially where non-compliance, non-linear pharmacokinetics, inadequate absorption, a narrow therapeutic window, suspected drug interaction or unexpected toxicity are encountered. Recommended indications for voriconazole and posaconazole TDM in the clinical management of haematology patients are provided. With emerging knowledge regarding the impact of pharmacogenomics upon metabolism of azole agents (particularly voriconazole), potential applications of pharmacogenomic evaluation to clinical practice are proposed.

Diagnosis and treatment of invasive fungal infections in the cancer patient: recent progress and ongoing questions

In the last 5 years we have witnessed further developments in diagnosis and treatment of invasive fungal infections (IFIs) that complicate cancer chemotherapy. In this brief overview, we highlight some advancement, discuss future directions, and unmet needs in this complex area.

Role of antimicrobial prophylaxis during treatment of adults with acute leukemia

Patients with acute leukemia (AL) are at high risk for developing bacterial, viral and fungal infections during chemotherapy. Because these infections cause considerable morbidity and mortality, prevention is attractive. In recent decades, several trials have established the benefit of prophylactic antimicrobials in patients with AL. Administration of prophylactic fluoroquinolone, acyclovir and triazole is recommended in neutropenic patients with AL by both the USA and European national guidelines. The potential for antimicrobial resistance as a long-term consequence of prophylaxis, however, is a concern. The recent development of nonculture-based diagnostic tests for invasive fungal infections has made early diagnosis and targeted treatment a promising future strategy as an alternative to mold-active prophylaxis.

Efficacy of the investigational echinocandin ASP9726 in a guinea pig model of invasive pulmonary aspergillosis

ASP9726 is an investigational echinocandin with in vitro activity against Aspergillus species. We evaluated the pharmacokinetics and efficacy of this agent in an established guinea pig model of invasive pulmonary aspergillosis. ASP9726 plasma concentrations were measured in guinea pigs administered either a single dose or multiple doses of this agent at 2.5, 5, and 10 mg/kg of body weight/day by subcutaneous injection. Immunosuppressed guinea pigs were inoculated with A. fumigatus AF293, and ASP9726 (2.5, 5, and 10 mg/kg/day), voriconazole (10 mg/kg by oral gavage twice daily), or caspofungin (3 mg/kg/day by intraperitoneal injection) was administered for 8 days. Changes in fungal burden were measured by enumerating CFU and by quantitative PCR of specimens from within the lungs, as well as by analysis of serum (1 → 3)-β-D-glucan and galactomannan. Lung histopathology was also evaluated. ASP9726 plasma concentrations increased in a dose-proportional manner, and the drug was well tolerated at each dose. Each dose of ASP9726, voriconazole, and caspofungin significantly reduced pulmonary fungal burden as measured by quantitative PCR and by determining (1 → 3)-β-D-glucan and galactomannan levels, but only voriconazole significantly reduced numbers of CFU. ASP9726 at 5 mg/kg also significantly improved survival. Histopathology demonstrated morphological changes in hyphae in animals exposed to ASP9726 and caspofungin, consistent with the activities of the echinocandins. These results suggest that ASP9726 may be efficacious for the treatment of invasive pulmonary aspergillosis.

Potential drug interactions and chemotoxicity in older patients with cancer receiving chemotherapy

PURPOSE

Increased risk of drug interactions due to polypharmacy and aging-related changes in physiology among older patients with cancer is further augmented during chemotherapy. No previous studies examined potential drug interactions (PDIs) from polypharmacy and their association with chemotherapy tolerance in older patients with cancer.

METHODS

This study is a retrospective medical chart review of 244 patients aged 70+ years who received chemotherapy for solid or hematological malignancies. PDI among all drugs, supplements, and herbals taken with the first chemotherapy cycle were screened for using the Drug Interaction Facts software, which classifies PDIs into five levels of clinical significance with level 1 being the highest. Descriptive and correlative statistics were used to describe rates of PDI. The association between PDI and severe chemotoxicity was tested with logistic regressions adjusted for baseline covariates.

RESULTS

A total of 769 PDIs were identified in 75.4% patients. Of the 82 level 1 PDIs identified among these, 32 PDIs involved chemotherapeutics. A large proportion of the identified PDIs were of minor clinical significance. The risk of severe non-hematological toxicity almost doubled with each level 1 PDI (OR=1.94, 95% CI: 1.22-3.09), and tripled with each level 1 PDI involving chemotherapeutics (OR=3.08, 95% CI: 1.33-7.12). No association between PDI and hematological toxicity was found.

CONCLUSIONS

In this convenience sample of older patients with cancer receiving chemotherapy we found notable rates of PDI and a substantial adjusted impact of PDI on risk of non-hematological toxicity. These findings warrant further research to optimize chemotherapy outcomes.

Voriconazole and its clinical potential in the prophylaxis of systemic fungal infection in patients with hematologic malignancies: a perspective review

Invasive fungal infections (IFIs) have become high prevalence in patients with hematologic malignancies. Drug-based strategies for IFIs include various approaches such as prophylactic, empiric, preemptive, and directed treatment. Prophylaxis is an attractive strategy in high-risk patients, given the lack of reliable diagnostics and the high mortality rate associated with IFIs. Prophylaxis includes the use of antifungal drugs in all patients at risk. An ideal antifungal compound for prophylaxis should have a potent and broad activity, be available both orally and intravenously, and have a low toxicity profile. Voriconazole fulfills all these criteria. The clinical efficacy of voriconazole against the majority of fungal pathogens makes it potentially very useful for the prevention of IFIs in patients with hematologic malignancies. Voriconazole appears to be very effective for the primary and secondary prevention of IFIs in these patients and recipients of allogeneic hematopoietic stem-cell transplantation. Randomized controlled trials evaluating voriconazole as primary antifungal prophylaxis in patients with neutropenia treated for a variety of hematologic malignancies have been performed, confirming its value as a prophylactic agent. Voriconazole is generally safe and well tolerated; however, its use is also associated with a number of concerns. In most patients with hematologic malignancies there is the potential for pharmacokinetic drug-drug interactions given that voriconazole is metabolized through the P450 cytochrome system.

Itraconazole: an update on pharmacology and clinical use for treatment of invasive and allergic fungal infections

INTRODUCTION

Fungal infections are a major source of global morbidity and mortality. Itraconazole is a triazole antifungal agent that is widely used for the prevention and treatment of fungal infection. While newer antifungal agents are now available, itraconazole is an orally bioavailable agent with broad-spectrum antifungal activity. Itraconazole remains a useful drug for the management of allergic and invasive mycoses worldwide.

AREAS COVERED

This article provides a summary of the pharmacokinetics, pharmacodynamics and clinical uses of itraconazole. Additionally, the authors summarise the safety and recently described toxicodynamics and discuss the value of therapeutic drug monitoring (TDM) with itraconazole. The following search criteria were constructed in order to identify relevant literature using PubMed and Ovid-MEDLINE: itraconazole, triazole, pharmacokinetics, pharmacodynamics, toxicodynamics and TDM. Relevant abstracts and articles identified from reviewing secondary citations were additionally retrieved and included if relevant.

EXPERT OPINION

Itraconazole remains an important agent in the prevention and treatment of fungal infection. Itraconazole has a broad-spectrum of activity and is available in both an intravenous and oral form making long-term use in chronic mycoses practical. Itraconazole is widely used for the treatment of endemic fungal infections. Pharmacokinetic variability and clinically important drug interactions make TDM of itraconazole an important consideration.

Antifungal therapy in children: an update

Invasive fungal infections are a common problem in children affected by primary or secondary immunodeficiencies. Thanks to an increased knowledge about their mechanisms of action and their pharmacokinetic and toxicity profiles, the use of these drugs in common and uncommon invasive infections in immunocompromised children has improved over the last decades. Choosing the most appropriate antifungal drug is a serious challenge for any clinician, also considering that, in most cases, therapy has to be started before cultures are available, the choice being driven by clinical symptoms and statistical criteria only. In this study, we performed a systematic review of literature, providing antifungal treatment recommendations for paediatric patients which can help clinicians find the most suitable treatment for each specific case. Principal antifungal drugs-ranging from first-generation antimycotics to the latest molecules-are classified according to their targets, and of each group, the pharmacokinetic profile, clinical indications and side effects are extensively described.

Antifungal activity of azole compounds CPA18 and CPA109 against azole-susceptible and -resistant strains of Candida albicans

OBJECTIVES

In this study we investigated the in vitro fungistatic and fungicidal activities of CPA18 and CPA109, two azole compounds with original structural features, alone and in combination with fluconazole against fluconazole-susceptible and -resistant Candida albicans strains.

METHODS

Antifungal activities were measured by MIC evaluation and time-kill studies. Azole binding analysis was performed by UV-Vis spectroscopy. Hyphal growth inhibition and filipin and propidium iodide staining assays were used for morphological analysis. An analysis of membrane lipids was also performed to gauge alterations in membrane composition and integrity. Synergism was calculated using fractional inhibitory concentration indices (FICIs). Evaluation of cytotoxicity towards murine macrophages was performed to verify selective antifungal activity.

RESULTS

Even though their binding affinity to C. albicans Erg11p is comparable to that of fluconazole, CPA compounds are active against resistant strains of C. albicans with a mutation in ERG11 sequences and/or overexpressing the ABC transporter genes CDR1 and CDR2, which encode ATP-dependent efflux pumps. Moreover, CPA18 is fungistatic, even against the two resistant strains, and was found to be synergistic with fluconazole. Differently from fluconazole and other related azoles, CPA compounds induced marked changes in membrane permeability and dramatic alterations in membrane lipid composition.

CONCLUSIONS

Our outcomes suggest that CPA compounds are able to overcome major mechanisms of resistance in C. albicans. Also, they are promising candidates for combination treatment that could reduce the toxicity caused by high fluconazole doses, particularly in immunocompromised patients.

Azole interactions with multidrug therapy in pediatric oncology

Patients with cancer receive multidrug therapy. Antineoplastic agents and supportive care drugs are often administered together, leading to potential drug-drug interactions. These interactions may have significant clinical implications in terms of toxicity or a decrease in the efficacy of the treatment administered. Here, we focus on the role of azoles and their main pharmacokinetic interactions with the principal classes of drugs used in pediatric oncology. The co-administration of azoles and antineoplastic agents, corticosteroids, immunosuppressants, antacids, antiemetics, antiepileptic drugs and analgesics was investigated, and a practical guide on the management of these drugs when administered together is provided.

Management of drug and food interactions with azole antifungal agents in transplant recipients

Azole antifungal agents are frequently used in hematopoietic stem cell and solid organ transplant recipients for prevention or treatment of invasive fungal infections. However, because of metabolism by or substrate activity for various isoenzymes of the cytochrome P450 system and/or P-glycoprotein, azole antifungals have the potential to interact with many of the drugs commonly used in these patient populations. Thus, to identify drug interactions that may result between azole antifungals and other drugs, we conducted a literature search of the MEDLINE database (1966-December 2009) for English-language articles on drug interaction studies involving the azole antifungal agents fluconazole, itraconazole, voriconazole, and posaconazole. Another literature search between each of the azoles and the immunosuppressants cyclosporine, tacrolimus, and sirolimus, as well as the corticosteroids methylprednisolone, dexamethasone, prednisolone, and prednisone, was also conducted. Concomitant administration of azoles and immunosuppressive agents may cause clinically significant drug interactions resulting in extreme immunosuppression or toxicity. The magnitude and duration of an interaction between azoles and immunosuppressants are not class effects of the azoles, but differ between drug combinations and are subject to interpatient variability. Drug interactions in the transplant recipient receiving azole therapy may also occur with antibiotics, chemotherapeutic agents, and acid-suppressive therapies, among other drugs. Initiation of an azole antifungal in transplant recipients nearly ensures a drug-drug interaction, but often these drugs are required. Management of these interactions first involves knowledge of the potential drug interaction, appropriate dosage adjustments when necessary, and therapeutic or clinical monitoring at an appropriate point in therapy to assess the drug-drug interaction (e.g., immunosuppressive drug concentrations, signs and symptoms of toxicity). These aspects of drug interaction management are essential not only at the initiation of azole antifungal therapy, but also when these agents are removed from the regimen.

Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 update by the infectious diseases society of america

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia. Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving. What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens. Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care-associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Antifungal prophylaxis during treatment for haematological malignancies: are we there yet?

Antifungal prophylaxis during treatment for haematological malignancies has been studied for 50 years, yet it has not been wholly effective even when using antifungal drugs that exhibit potent activity in vitro against a broad range of fungal pathogens. Trials have demonstrated that it can reduce the incidence of invasive fungal diseases (IFD) and fungal deaths, but only two studies have had an impact on overall mortality. Furthermore, it has not significantly reduced the need for empirical antifungal therapy. Posaconazole was effective in preventing invasive aspergillosis in two studies of high-risk patients, and consensus guidelines grade it as a suitable choice for antifungal prophylaxis of invasive mould disease; however, its bioavailability was compromised by vomiting or diarrhoea so that an alternative parenteral antifungal drug was required. A recent trial of voriconazole prophylaxis after allogeneic stem cell transplantation failed to show superiority over fluconazole. With more accurate definitions of IFD, that utilize fungal biomarkers, such as galactomannan, together with computerized tomographic imaging, there is growing interest in a diagnostic-driven strategy, which could prove to be a more efficacious approach.

Executive Summary: Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer: 2010 Update by the Infectious Diseases Society of America

This document updates and expands the initial Infectious Diseases Society of America (IDSA) Fever and Neutropenia Guideline that was published in 1997 and first updated in 2002. It is intended as a guide for the use of antimicrobial agents in managing patients with cancer who experience chemotherapy-induced fever and neutropenia.

Recent advances in antimicrobial drug development and technology, clinical trial results, and extensive clinical experience have informed the approaches and recommendations herein. Because the previous iteration of this guideline in 2002, we have a developed a clearer definition of which populations of patients with cancer may benefit most from antibiotic, antifungal, and antiviral prophylaxis. Furthermore, categorizing neutropenic patients as being at high risk or low risk for infection according to presenting signs and symptoms, underlying cancer, type of therapy, and medical comorbidities has become essential to the treatment algorithm. Risk stratification is a recommended starting point for managing patients with fever and neutropenia. In addition, earlier detection of invasive fungal infections has led to debate regarding optimal use of empirical or preemptive antifungal therapy, although algorithms are still evolving.

What has not changed is the indication for immediate empirical antibiotic therapy. It remains true that all patients who present with fever and neutropenia should be treated swiftly and broadly with antibiotics to treat both gram-positive and gram-negative pathogens.

Finally, we note that all Panel members are from institutions in the United States or Canada; thus, these guidelines were developed in the context of North American practices. Some recommendations may not be as applicable outside of North America, in areas where differences in available antibiotics, in the predominant pathogens, and/or in health care–associated economic conditions exist. Regardless of venue, clinical vigilance and immediate treatment are the universal keys to managing neutropenic patients with fever and/or infection.

Correlation of in vitro activity and in vivo efficacy of itraconazole intravenous and oral solubilized formulations by testing Candida strains with various itraconazole susceptibilities in a murine invasive infection

OBJECTIVES

To examine whether in vitro antifungal susceptibility test results correlate with in vivo efficacy of two cyclodextrin-solubilized itraconazole formulations (intravenous and oral) against Candida in a murine model of invasive infection.

METHODS

A selected set of 12 Candida spp. strains with various itraconazole susceptibilities were tested. We studied the efficacy of intravenous and oral itraconazole administered once daily at dosages of 0.63, 2.5, 10 and 40 mg/kg body weight in mice lethally infected with each tested strain. Survival of mice in each treated group was monitored daily until the death of all control mice and compared between groups.

RESULTS

Survival of mice infected with 9 of 12 Candida strains with itraconazole MICs of ≤0.016-2.0 mg/L was significantly prolonged by treatment with intravenous itraconazole at dosages of 2.5 or 10 mg/kg and above. In contrast, the other three strains resistant to 8 mg/L itraconazole in vitro were refractory to the therapy, even at the highest itraconazole dosage (40 mg/kg). Closely similar in vivo data were obtained with the oral itraconazole therapy. The effective doses of the two itraconazole formulations increased with increasing itraconazole MICs for the infecting strains.

CONCLUSIONS

The in vivo efficacy of intravenous and oral itraconazole correlated with the in vitro susceptibility data.

Randomized, double-blind trial of fluconazole versus voriconazole for prevention of invasive fungal infection after allogeneic hematopoietic cell transplantation

Invasive fungal infection (IFI) is a serious threat after allogeneic hematopoietic cell transplant (HCT). This multicenter, randomized, double-blind trial compared fluconazole (N = 295) versus voriconazole (N = 305) for the prevention of IFI in the context of a structured fungal screening program. Patients undergoing myeloablative allogeneic HCT were randomized before HCT to receive study drugs for 100 days, or for 180 days in higher-risk patients. Serum galactomannan was assayed twice weekly for 60 days, then at least weekly until day 100. Positive galactomannan or suggestive signs triggered mandatory evaluation for IFI. The primary endpoint was freedom from IFI or death (fungal-free survival; FFS) at 180 days. Despite trends to fewer IFIs (7.3% vs 11.2%; P = .12), Aspergillus infections (9 vs 17; P = .09), and less frequent empiric antifungal therapy (24.1% vs 30.2%, P = .11) with voriconazole, FFS rates (75% vs 78%; P = .49) at 180 days were similar with fluconazole and voriconazole, respectively. Relapse-free and overall survival and the incidence of severe adverse events were also similar. This study demonstrates that in the context of intensive monitoring and structured empiric antifungal therapy, 6-month FFS and overall survival did not differ in allogeneic HCT recipients given prophylactic fluconazole or voriconazole. This trial was registered at www.clinicaltrials.gov as NCT00075803.

Invasive fungal disease in patients treated for newly diagnosed acute leukemia

Invasive fungal disease (IFD) is a significant cause of morbidity and mortality in patients undergoing treatment for acute leukemia (AL). Antifungal prophylactic strategies are associated with significant toxicities and cost. We performed a retrospective study of the incidence and risk factors for IFD among patients newly diagnosed with and treated for AL between January 1, 2004 and July 1, 2006. Patient follow up concluded January 1, 2007. Among 231 patients with newly diagnosed AL, 31 (13.4%) developed IFD by the end of follow up, 24 (10.4%) of whom developed IFD within the first 100 days after diagnosis of AL. The cumulative probability of developing IFD was 5.9% by 30 days and 11.1% at 100 days after AL diagnosis. Patients who had persistent leukemia after an initial course of induction chemotherapy were significantly more likely to develop IFD than those who did not have evidence of persistent leukemia (14/65 (21.5%) vs. 15/148 (10.1%), P = 0.03). In a time-dependent Cox model, the adjusted hazard ratio for developing IFD within the first 100 days of AL diagnosis based on the number of days of neutropenia in that period was 4.85 (95% confidence interval: 1.52, 15.4). Those patients with more days of neutropenia in the first 100 days after AL diagnosis, such as those who did not achieve remission after a first course of induction chemotherapy, were more likely to develop IFD.