Itraconazole-related increased vincristine neurotoxicity: case report and review of literature

Vincristine Side Effects With Concomitant Fluconazole Use During Induction Chemotherapy in Pediatric Acute Lymphoblastic Leukemia

As a mainstay of treatment for acute lymphoblastic leukemia (ALL), vincristine's side effect profile is well known. Parallel administration of the antifungal fluconazole has been shown to interfere with the metabolism of vincristine, potentially resulting in increased side effects. We conducted a retrospective chart review to determine whether concomitant administration of vincristine and fluconazole during pediatric ALL induction therapy impacted the frequency of vincristine side effects, namely, hyponatremia and peripheral neuropathy. We also evaluated whether the incidence of opportunistic fungal infections was impacted by fluconazole prophylaxis. Medical charts of all pediatric ALL patients treated with induction chemotherapy at Children's Hospital and Medical Center in Omaha, NE, from 2013 to 2021 were retrospectively reviewed. Fluconazole prophylaxis did not significantly impact the rate of fungal infections. We found no correlation between fluconazole use and increased incidence of hyponatremia or peripheral neuropathy, which supports the safety of fungal prophylaxis with fluconazole during pediatric ALL induction therapy.

Ileus induced by the combination of vinca alkaloids and posaconazole in a patient with acute lymphoblastic leukemia: a case report and literature review

Vinca alkaloid (VA)-induced ileus, a rare but severe autonomic neuropathy, can be enhanced by concomitant use of antifungal triazole agents. We herein present a case of VA-induced ileus in a 17-year-old girl who was diagnosed with B-cell acute lymphoblastic leukemia. On day 1, the patient received cyclophosphamide, vincristine, and methylprednisolone. On day 2, she began treatment with posaconazole oral suspension at 200 mg three times daily for prophylaxis against invasive fungal infection. On day 5, she began induction therapy consisting of vindesine, methylprednisolone, daunorubicin, and cyclophosphamide. The patient developed severe abdominal pain with marked constipation on day 11 and was diagnosed with incomplete ileus. After switching the antifungal agent to micafungin, performing gastrointestinal decompression, administering parenteral nutrition, and omitting the fourth dose of vindesine, the ileus symptoms were relieved. This case emphasizes the potential interaction between VAs and posaconazole. We also herein present a review of the literature on ileus caused by the combination of VAs and antifungal triazole agents. In clinical practice, physicians and pharmacists should be aware of the possibility of ileus caused by the use of VAs in combination with posaconazole. It is important to reduce complications during chemotherapy to improve patients' prognosis.

Vincristine-Induced Peripheral Neuropathy (VIPN) in Pediatric Tumors: Mechanisms, Risk Factors, Strategies of Prevention and Treatment

Vincristine-induced peripheral neurotoxicity (VIPN) is a very common side effect of vincristine chemotherapy among pediatric patients with cancer. Neuropathy may be sensory, motor and/or autonomic, with consequent reduction, delay or discontinuation of vincristine-chemotherapy, but also pain, disability, reduced quality of life of patients and an increase in medical costs. Vincristine acts out its antineoplastic function by altering the normal assembly and disassembly of microtubules, with their consequent mitosis block and death. Vincristine leads to VIPN through a complex mechanism of damage, which occurs not only on the microtubules, but also on the endothelium and the mitochondria of nerve cells. Furthermore, both patient-related risk factors (age, race, ethnicity and genetic polymorphisms) and treatment-related risk factors (dose, time of infusion and drug–drug interactions) are involved in the pathogenesis of VIPN. There is a lack of consensus about the prophylaxis and treatment of VIPN among pediatric oncologic patients, despite several molecules (such as gabapentin, pyridoxine and pyridostigmine, glutamic acid and glutamine) having been already investigated in clinical trials. This review describes the molecular mechanisms of VIPN and analyzes the risk factors and the principal drugs adopted for the prophylaxis and treatment of VIPN in pediatric patients with cancer.

Benefits of risk-adapted and mould-specific antifungal prophylaxis in childhood leukaemia

Fluconazole is one of the most commonly used drugs for antifungal prophylaxis in childhood leukaemia. However, its interaction with vincristine may induce neuropathy and the emergence of antifungal drug resistance contributes to substantial mortality caused by invasive fungal infections (IFIs). In a retrospective single‐centre study, we compared tolerability and outcome of different antifungal prophylaxis strategies in 198 children with acute leukaemia (median age 5·3 years). Until 2010, antifungal prophylaxis with fluconazole was offered to most of the patients and thereafter was replaced by liposomal amphotericin‐B (L‐AMB) and restricted to high‐risk patients only. Vincristine‐induced neurotoxicity was significantly reduced under L‐AMB, as the percentage of patients with severe constipation decreased (15·4% vs. 3·7%, before vs. after 31 December·2010, P = 0·01) and stool frequency increased by up to 38% in polyene‐treated patients (P = 0·005). Before 2011, 10 patients developed confirmed IFIs, most of them were infected with Aspergillus species. After risk adaption in 2011, IFIs were completely prevented (P = 0·007).

L‐AMB prophylaxis is beneficial in childhood leukaemia patients, as it offers effective antifungal activity with improved tolerability as compared to fluconazole. The potential impact of our risk‐adapted antifungal treatment should be included in current prophylaxis guidelines for childhood leukaemia.

Pharmacokinetics and population pharmacokinetics in pediatric oncology

Pharmacokinetic research has become increasingly important in pediatric oncology as it can have direct clinical implications and is a crucial component in individualized medicine. Population pharmacokinetics has become a popular method especially in children, due to the potential for sparse sampling, flexible sampling times, computing of heterogeneous data, and identification of variability sources. However, population pharmacokinetic reports can be complex and difficult to interpret. The aim of this article is to provide a basic explanation of population pharmacokinetics, using clinical examples from the field of pediatric oncology, to facilitate the translation of pharmacokinetic research into the daily clinic.

Vincristine toxicity with co-administration of fluconazole during induction therapy for pediatric acute lymphoblastic leukemia

BACKGROUND

Antifungal prophylaxis is recommended for patients with acute lymphoblastic leukemia (ALL) during high-risk periods such as induction; however, increased vincristine toxicities have been reported with the co-administration of triazole antifungals. We sought to determine whether vincristine-associated toxicities are higher among children with ALL concurrently given fluconazole prophylaxis compared to no prophylaxis.

PROCEDURE

Using a retrospective cohort design, we reviewed records of pediatric patients treated for newly diagnosed ALL from 2003 to 2013. Patients were classified by fluconazole exposure during induction. The development of vincristine-associated toxicity and vincristine dose adjustment were the primary outcomes evaluated. The adjusted risk difference (RD) for vincristine-related toxicity associated with triazole exposure was determined.

RESULTS

We identified 197 patients meeting inclusion criteria for evaluation, 160 (81%) of whom received fluconazole prophylaxis. Among patients receiving fluconazole, 36/160 (22%) developed vincristine toxicity compared to 7/37 (19%) among those not receiving prophylaxis (RD: 3%, 95% confidence interval [CI] -11 to 18%). Adjusting for patient age and race, no statistically significant increased risk for vincristine-associated toxicity with fluconazole exposure was observed (RD 5%, 95% CI -8 to 17%). An increased risk for vincristine-associated toxicity was independently associated with age 10 years or older (RD 19%, 95% CI 4-34%).

CONCLUSION

Co-administration of fluconazole during induction therapy for pediatric ALL does not significantly increase the risk for vincristine-associated toxicities; however, patients 10 years or older are at an increased risk for toxicity independent of fluconazole exposure. Prophylaxis with fluconazole during induction therapy for pediatric ALL, if warranted, appears to be a safe clinical practice.

Syndrome of inappropriate antidiuretic hormone secretion from concomitant use of itraconazole and vindesine

WHAT IS KNOWN AND OBJECTIVE

Several studies have reported that itraconazole-induced inhibition of vincristine (VCR) metabolism might result in neurological impairment and syndrome of inappropriate antidiuretic hormone (SIADH). However, there are few reports concerning adverse drug reactions (ADRs) resulting from concomitant use of vindesine (VDS) and itraconazole. Here, we report the first case of adverse drug interactions (ADIs) between itraconazole and VDS in a Chinese child with acute lymphocytic leukaemia (ALL).

CASE SUMMARY

A 4-year-old boy was diagnosed with standard-risk ALL and was receiving VDS (3 mg/m² ) for maintenance therapy and itraconazole for IFI recurrence. Severe neurotoxicity, consisting mainly of trismus and SIADH, was noticed after 7 days of VDS administration. After discontinuation of itraconazole and its replacement with caspofungin, the patient recovered from neurological signs and symptoms. The ADIs can be explained by VDS accumulation owing to inherent loss of CYP3A5 (*3/*3) function, and inhibition of CYP3A4 activity by itraconazole.

WHAT IS NEW AND CONCLUSION

Syndrome of inappropriate antidiuretic hormone from co-administration of itraconazole and VDS has not previously been reported to our knowledge. We suggest that the concomitant use of these drugs should be avoided if possible. The use of alternative antifungal drugs (AFDs) should be considered, and ADRs should be closely monitored when the combination of itraconazole and VDS is unavoidable.

Evaluation of the implementation rate of primary antifungal prophylaxis and the prognosis of invasive fungal disease in acute leukemia patients in China

BACKGROUND

Invasive fungal disease (IFD) is a major complication of acute leukemia, thus primary antifungal prophylaxis (PAP) is recommended by guidelines. Nevertheless, guidelines might not be commonly followed in developing countries due to economic factors. The primary objectives were to evaluate the implementation rate of PAP in acute leukemia patients in China and to compare the prognosis of IFD with and without PAP. The secondary objectives were to investigate the safety of PAP, clinical characteristics of IFDs and risk factors of breakthrough.

METHODS

This was a retrospective observational single-center study, including non-M3 acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) patients receiving uniform induction or salvage chemotherapy between 2012 and 2016.

RESULTS

There were 29.4% of patients without PAP among a total of 248 cases. The incidence of breakthrough proven/probable/possible IFDs was 24.7%, 6.5%, 5.5%, 5.4% and 5.3% in control (no prophylaxis), fluconazole, itraconazole, voriconazole and posaconazole group respectively (P = 0.007), while the percentage of patients requiring empirical or pre-emptive therapy was 54.8%, 45.7%, 23.3%, 18.9%, 10.5% respectively (P < 0.001). PAP could also significantly improve IFD-free survival (P < 0.001) and reduce 90-day overall mortality in patients on AML salvage regimen (P = 0.021). There were no statistical differences in PAP-related adverse events. Past history of IFD (OR 9.5, P = 0.006) was confirmed to be independent risk factors.

CONCLUSIONS

There are a considerable number of acute leukemia patients without PAP in China, who have higher IFD incidence, increased empiric/pre-emptive antifungal drug use and worse IFD-free survival.

Involvement of Cannabinoid Signaling in Vincristine-Induced Gastrointestinal Dysmotility in the Rat

Background: In different models of paralytic ileus, cannabinoid receptors are overexpressed and endogenous cannabinoids are massively released, contributing to gastrointestinal dysmotility. The antitumoral drug vincristine depresses gastrointestinal motility and a similar mechanism could participate in this effect. Therefore, our aim was to determine, using CB₁ and CB₂ antagonists, whether an increased endocannabinoid tone is involved in vincristine-induced gastrointestinal ileus.

Methods: First, we confirmed the effects of vincristine on the gut mucosa, by conventional histological techniques, and characterized its effects on motility, by radiographic means. Conscious male Wistar rats received an intraperitoneal injection of vincristine (0.1–0.5 mg/kg), and barium sulfate (2.5 ml; 2 g/ml) was intragastrically administered 0, 24, or 48 h later. Serial X-rays were obtained at different time-points (0–8 h) after contrast. X-rays were used to build motility curves for each gastrointestinal region and determine the size of stomach and caecum. Tissue samples were taken for histology 48 h after saline or vincristine (0.5 mg/kg). Second, AM251 (a CB₁ receptor antagonist) and AM630 (a CB₂ receptor antagonist) were used to determine if CB₁ and/or CB₂ receptors are involved in vincristine-induced gastrointestinal dysmotility.

Key results: Vincristine induced damage to the mucosa of ileum and colon and reduced gastrointestinal motor function at 0.5 mg/kg. The effect on motor function was particularly evident when the study started 24 h after administration. AM251, but not AM630, significantly prevented vincristine effect, particularly in the small intestine, when administered thrice. AM251 alone did not significantly alter gastrointestinal motility.

Conclusions: The fact that AM251, but not AM630, is capable of reducing the effect of vincristine suggests that, like in other experimental models of paralytic ileus, an increased cannabinoid tone develops and is at least partially responsible for the alterations induced by the antitumoral drug on gastrointestinal motor function. Thus, CB₁ antagonists might be useful to prevent/treat ileus induced by vincristine.

Clinical Analysis of Adverse Drug Reactions between Vincristine and Triazoles in Children with Acute Lymphoblastic Leukemia

Background

Vincristine (VCR) is a major chemotherapy drug for treatment of childhood acute lymphoblastic leukemia (ALL). Triazole antifungal drugs (AFD) are the main agents for the prevention/treatment of invasive fungal infection (IFI), a common complication during the treatment of ALL. This study investigated the adverse drug reactions (ADRs) between VCR and AFD.

Material/Methods

A retrospective study was performed on 68 children with ALL (39 boys and 29 girls, median age: 5 years) who were treated with VCR chemotherapy (a total of 136 cases, including both induction and reinduction phases) from January 2012 to December 2013 in our hospital. These cases were divided into 4 groups: the control group without AFD prevention/treatment (n=44), the Itra group receiving itraconazole oral solution (n=44), the Fluc group receiving intravenous fluconazole (n=42), and the Vori group receiving voriconazole oral tablets (n=6). The ADRs in each group was recorded and compared.

Results

The incidence of ADRs in the Itra and Vori groups were significantly higher compared with the Fluc and the control group (P<0.05). The incidence of ADRs in the Itra group was significantly higher than that in the Vori group, whereas there was no difference in the incidence between the Fluc and control group.

Conclusions

Given the lower incidence of ADRs between VCR and fluconazole compared with voriconazole or itraconazole, it is relatively safer to use fluconazole in ALL patients receiving VCR chemotherapy. The occurrence of ADRs should be closely monitored when triazoles must be administered concomitantly with VCR.

Advances in the treatment of invasive neonatal candidiasis

INTRODUCTION

Invasive candidiasis is responsible for ∼ 10% of nosocomial sepsis in very-low-birth-weight infants and is associated with substantial morbidity and mortality. Over the last two decades, the antifungal armamentarium against Candida spp. has increased; however, efficacy and safety studies in this population are lacking.

AREAS COVERED

We reviewed the medical literature and extracted information on clinical and observational studies evaluating the use of antifungal agents in neonates with invasive candidiasis.

EXPERT OPINION

Efficacy and safety data for antifungals in neonates are lacking, and the majority of studies conducted to date have concentrated on pharmacokinetic/pharmacodynamic evaluations. Unlike other anti-infective agents, efficacy data in the setting of neonatal candidiasis cannot be extrapolated from adult studies due to differences in the pathophysiology of the disease in this population relative to older children and adults. Data for amphotericin B deoxycholate, fluconazole, and micafungin suggest that these are the current agents of choice for this disease in neonates until data for newer antifungal agents become available. For prophylaxis, data from fluconazole randomized controlled trials will be submitted to the regulatory agencies for labeling. Ultimately, the field of therapeutics for neonatal candidiasis will require multidisciplinary collaboration given the numerous challenges associated with conducting clinical trials in neonates.

Repurposing Drugs in Oncology (ReDO)-itraconazole as an anti-cancer agent

Itraconazole, a common triazole anti-fungal drug in widespread clinical use, has evidence of clinical activity that is of interest in oncology. There is evidence that at the clinically relevant doses, itraconazole has potent anti-angiogenic activity, and that it can inhibit the Hedgehog signalling pathway and may also induce autophagic growth arrest. The evidence for these anticancer effects, in vitro, in vivo, and clinical are summarised, and the putative mechanisms of their action outlined. Clinical trials have shown that patients with prostate, lung, and basal cell carcinoma have benefited from treatment with itraconazole, and there are additional reports of activity in leukaemia, ovarian, breast, and pancreatic cancers. Given the evidence presented, a case is made that itraconazole warrants further clinical investigation as an anti- cancer agent. Additionally, based on the properties summarised previously, it is proposed that itraconazole may synergise with a range of other drugs to enhance the anti-cancer effect, and some of these possible combinations are presented in the supplementary materials accompanying this paper.

Design of a drug-drug interaction study of vincristine with azole antifungals in pediatric cancer patients using clinical trial simulation

BACKGROUND

The aim of the current work was to perform a clinical trial simulation (CTS) analysis to optimize a drug-drug interaction (DDI) study of vincristine in children who also received azole antifungals, taking into account challenges of conducting clinical trials in this population, and, to provide a motivating example of the application of CTS in the design of pediatric oncology clinical trials.

PROCEDURE

A pharmacokinetic (PK) model for vincristine in children was used to simulate concentration-time profiles. A continuous model for body surface area versus age was defined based on pediatric growth curves. Informative sampling time windows were derived using D-optimal design. The CTS framework was used to different magnitudes of clearance inhibition (10%, 25%, or 40%), sample size (30-500), the impact of missing samples or sampling occasions, and the age distribution, on the power to detect a significant inhibition effect, and in addition, the relative estimation error (REE) of the interaction effect.

RESULTS

A minimum group specific sample size of 38 patients with a total sample size of 150 patients was required to detect a clearance inhibition effect of 40% with 80% power, while in the case of a lower effect of clearance inhibition, a substantially larger sample size was required. However, for the majority of re-estimated drug effects, the inhibition effect could be estimated precisely (REE < 25%) in even smaller sample sizes and with lower effect sizes.

CONCLUSION

This work demonstrated the utility of CTS for the evaluation of PK clinical trial designs in the pediatric oncology population.

Liposomal forms of anticancer agents beyond anthracyclines: present and future perspectives

Liposomes are widely used as delivery systems of cytotoxic drugs. The encapsulation into liposomes improves pharmacological properties and as a result therapeutic index and outcomes. To date, liposomal vincristine and cytarabine are approved and marketed for intravenous and intrathecal administration, respectively. The main goal of this review is to examine the clinical use and pharmacological properties, as well as the safety of liposomal forms of less widely used liposomal forms of anticancer agents compared to their conventional forms and to present data regarding clinical development of other liposomal agents. Liposomal forms of cytarabine and vincristine are less widely used and unknown compared to liposomal anthracyclines, because they are approved only for specific indications and only in the United States.

Pharmacokinetics and pharmacodynamics of antifungals in children: clinical implications

Invasive fungal disease (IFD) remains life threatening in premature infants and immunocompromised children despite the recent development of new antifungal agents. Optimal dosing of antifungals is one of the few factors clinicians can control to improve outcomes of IFD. However, dosing in children cannot be extrapolated from adult data because IFD pathophysiology, immune response, and drug disposition differ from adults. We critically examined the literature on pharmacokinetics (PK) and pharmacodynamics (PD) of antifungal agents and highlight recent developments in treating pediatric IFD. To match adult exposure in pediatric patients, dosing adjustment is necessary for almost all antifungals. In young infants, the maturation of renal and metabolic functions occurs rapidly and can significantly influence drug exposure. Fluconazole clearance doubles from birth to 28 days of life and, beyond the neonatal period, agents such as fluconazole, voriconazole, and micafungin require higher dosing than in adults because of faster clearance in children. As a result, dosing recommendations are specific to bracketed ranges of age. PD principles of antifungals mostly rely on in vitro and in vivo models but very few PD studies specifically address IFD in children. The exposure-response relationship may differ in younger children compared with adults, especially in infants with invasive candidiasis who are at higher risk of disseminated disease and meningoencephalitis, and by extension severe neurodevelopmental impairment. Micafungin is the only antifungal agent for which a specific target of exposure was proposed based on a neonatal hematogenous Candida meningoencephalitis animal model. In this review, we found that pediatric data on drug disposition of newer triazoles and echinocandins are lacking, dosing of older antifungals such as fluconazole and amphotericin B products still need optimization in young infants, and that target PK/PD indices need to be clinically validated for almost all antifungals in children. A better understanding of age-specific PK and PD of new antifungals in infants and children will help improve clinical outcomes of IFD by informing dosing and identifying future research areas.

ATP Binding Cassette C1 (ABCC1/MRP1)-mediated drug efflux contributes to disease progression in T-lineage acute lymphoblastic leukemia

PURPOSE

In acute lymphoblastic leukemia (ALL), multidrug resistance is often mediated by ATPase Binding Cassette (ABC) proteins, which principally involve ABCB1 (multidrug resistance 1, MDR1) and ABCC1 (multidrug resistance protein 1, MRP1). However, direct comparisons between the differential effects of ABCB1 and ABCC1 have been difficult, since identical cell lines with differential expression of these transporters have not been developed.

EXPERIMENTAL DESIGN

In this study, we developed and compared the biological profiles of Jurkat cell lines that selectively over-expressed ABCB1 and ABCC1. Vincristine (VCR) plays an important role in the treatment of T-lineage ALL (T-ALL), and is often the first drug given to newly-diagnosed patients. Because of its importance in treatment, we provided escalating, sub-lethal doses of VCR to Jurkat cells, and extended our observations to expression profiling of newly diagnosed patients with T-ALL.

RESULTS

We found that VCR-resistant cells over-expressed ABCC1 nearly 30-fold. The calcein AM assay confirmed that VCR-resistant cells actively extruded VCR, and that ABCC1-mediated drug resistance conferred a different spectrum of multidrug resistance than other T-ALL induction agents. siRNA experiments that blocked ABCC1 export confirmed that VCR resistance could be reversed in vitro. Analyses of T-lymphoblasts obtained from 92 newly diagnosed T-ALL patients treated on Children's Oncology Group Phase III studies 8704/9404 showed that induction failure could be explained in all but one case by the over-expression of ABCB1 or ABCC1.

CONCLUSIONS

Taken together, these results suggest that over-expression of ABC transporters plays a contributing role in mediating treatment failure in T-ALL, and underscore the need to employ alternate treatment approaches in patients for whom induction failed or for those with relapsed disease.

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.

Potentiation of vincristine toxicity with concomitant fluconazole prophylaxis in children with acute lymphoblastic leukemia

Use of azole antifungals as prophylaxis is becoming an increasingly common practice in acute lymphoblastic leukemia (ALL). Limited literature in adults heightened the awareness of possible increased vincristine (VCR) toxicity in patients receiving concomitant azole therapy. This is due to inhibition of cytochrome P450 3A4, which may increase overall exposure to VCR, resulting in dose reductions or omissions. The primary objective of this study was to determine whether the use of fluconazole prophylaxis increases vincristine toxicity in children with ALL. The authors retrospectively evaluated children with ALL between January 2004 and December 2009. Patients were subdivided into 2 groups based on whether or not they received fluconazole prophylaxis during induction therapy. Data were collected for up to 3 months following the completion of induction therapy. Thirty-one patients were included for analysis. There was no significant difference in gender, race, steroid use, gastrointestinal (GI) toxicity, VCR dose modification, and the rate of fungal or bacterial infections between these 2 groups. Only advanced age is an independent predictor of neuropathy. Patients receiving fluconazole were 4.5 times more likely to experience neuropathy than those not receiving azole; however, this was not statistically significant. The authors report an increased incidence of VCR toxicity in patients with ALL receiving concomitant fluconazole prophylaxis. Judicious use of azole antifungals is warranted in children with ALL.

Two cases of paralitic ileus in onco-hematologic patients

Paralytic ileus is a severe complication resulting from a variety of disorders. It occurs most commonly in patients with serious underlying medical or surgical conditions. Prompt diagnosis and appropriate management may improve the outcome. We describe 2 cases of onco-hematologic patients who presented this complication after intensive chemotherapy.

Adverse interactions between antifungal azoles and vincristine: review and analysis of cases

Triazole and imidazole antifungal agents inhibit metabolism of vincristine, leading to excess vinca alkaloid exposure and severe neurotoxicity. Recent reports of debilitating interactions between vincristine and itraconazole, as well as posaconazole, voriconazole and ketoconazole underscore the need to improve medical awareness of this adverse combination. We, therefore, undertook a comprehensive analysis of reports of adverse drug interactions (ADIs) with the combination of vincristine and azole antifungal agents, established a new classification, and provided a detailed summary of these toxicities. In patients who had sufficient data for analysis, 47 individuals were identified who had an ADI with the combination of vincristine and antifungal azoles. Median age was 8 years (1.3-68 years) with 33(70%) having a diagnosis of acute lymphoblastic leukaemia. Median time to ADI with vincristine was 9.5 days with itraconazole, 13.5 days posaconazole and 30 days voriconazole. The median number of vincristine doses preceding the ADI was 2 doses with itraconazole, 3 doses posaconazole and 2 doses voriconazole. The most common severe ADIs included gastrointestinal toxicity, peripheral neuropathy, hyponatremia/SIADH, autonomic neuropathy and seizures. Recovery from these ADIs occurred in 80.6% of patients. We recommend using alternative antifungal agents if possible in patients receiving vincristine to avoid this serious and potentially life-threatening drug interaction.

Risk of azole-enhanced vincristine neurotoxicity in pediatric patients with hematological malignancies: old problem - new dilemma

One of the most well-known drug interactions in pediatric oncology concerns the co-administration of itraconazole, an antifungal triazole, and vincristine, an antileukemic agent, which seems to enhance the risk of neurotoxicity of the latter, mediated through the cytochrome CYP450 enzyme system. The aim of this article is to review the metabolism of these two drugs, to analyze the published cases with severe triazole-enhanced vincristine neurotoxicity, to discuss the pathophysiological mechanisms of this adverse effect, and to contribute in understanding the differences in triazole-vincristine interaction severity.

Clinically relevant drug interactions between anticancer drugs and psychotropic agents

Drug interactions are commonly seen in the treatment of cancer patients. Psychotropics are often indicated for these patients since they may also suffer from pre-existing psychological disorders or experience insomnia and anxiety associated with cancer therapy. Thus, the risk of anticancer drug (ACD)-psychotropic drug-drug interactions (DDIs) is high. Drug interactions were compiled from the British National Formulary (53rd edn), Lexi-Comp's Drug Information Handbook (15th edn), Micromedex (v5.1), Hansten & Horn's Drug Interactions (2000) and Drug Interaction Facts (2008 edn). Product information of the individual drugs, as well as documented literature on ACD-psychotropic interactions from PubMed and other databases was also incorporated. This paper identifies clinically important ACD-psychotropic DDIs that are frequently observed. Pharmacokinetic DDIs were observed for tyrosine kinase inhibitors, corticosteroids and antimicrotubule agents due to their inhibitory or inductive effects on cytochrome P450 isoenzymes. Pharmacodynamic DDIs were identified for thalidomide with central nervous system depressants, procarbazine with antidepressants, myelosuppressive ACDs with clozapine and anthracyclines with QT-prolonging psychotropics. Clinicians should be vigilant when psychotropics are prescribed concurrently with ACDs. Close monitoring of plasma drug levels should be carried out to avoid toxicity in the patient, as well as to ensure adequate chemotherapeutic and psychotropic coverage.

Itraconazole associated quadriparesis and edema: a case report

Introduction

Itraconazole is an anti-fungal agent widely used to treat various forms of mycosis. It is particularly useful in allergic bronchopulmonary aspergillosis and severe asthma with fungal sensitization. Side effects are uncommon and usually mild. Mild neuropathy is noted to occur very rarely. We present an unusual and, to the best of our knowledge, as yet unreported case of severe neuropathy and peripheral edema due to itraconazole in the absence of a concomitant risk factor.

Case presentation

A 72-year-old Caucasian man was started on itraconazole following diagnosis of severe asthma with fungal sensitization. One month later he presented with severe bilateral ankle edema with an elevated serum itraconazole level. The itraconazole dose was reduced but his ankle edema persisted and he developed weakness of all four limbs. Itraconazole was completely stopped leading to improvement in his leg edema but he became bed bound due to weakness. He gradually improved with supportive care and neurorehabilitation. On review at six months, our patient was able to mobilize with the aid of two elbow crutches and power had returned to 5/5 in distal extremities and 4+/5 in proximal extremities. The diagnosis was established based on the classical presentation of drug-induced neuropathy and negative investigatory findings for any alternative diagnoses.

Conclusion

We report the case of a patient presenting with an unusual complication of severe neuropathy and peripheral edema due to itraconazole. Clinicians should be alert to this association when encountered with neuropathy and/or edema in an itraconazole therapy recipient.

Adverse effects of treatment in childhood acute lymphoblastic leukemia: general overview and implications for long-term cardiac health

Survival of childhood acute lymphoblastic leukemia (ALL) is one of the greatest medical success stories of the last four decades. Unfortunately, childhood ALL survivors experience medical late effects that increase their risk of morbidity and premature death, often due to heart and vascular disease. Research has helped elucidate the mechanisms and trajectory of direct damage to the heart from treatment exposure, particularly to anthracyclines, and has also contributed knowledge on the influences of related chronic conditions, such as obesity and insulin resistance on heart health in these survivors. This article summarizes the key issues associated with early morbidity and mortality from cardiac-related disease in childhood ALL survivors and suggests directions for interventions to improve long-term outcomes.

Drug interactions in childhood cancer

Children with cancer are increasingly benefiting from new treatment strategies and advances in supportive care, as shown by improvements in both survival and quality-of-life. However, the continuous emergence of new cancer drugs and supportive-care drugs has increased the possibility of harmful drug interactions; health-care providers need to be very cautious when combining drugs. We discuss the most common interactions between chemotherapeutic drugs and supportive-care drugs-such as anticonvulsants, antiemetics, uric-acid-lowering compounds, acid suppressants, antimicrobials, and pain-management medications in paediatric patients. We also review the interactions between chemotherapy drugs and food and herbal supplements, and provide recommendations to avoid unwanted and potentially fatal interactions in children with cancer. Because of the constant release of new drugs, health-care providers need to check the most recent references before making recommendations about drug interactions.

Vincristine and intestinal pseudo-obstruction in children: report of 5 cases, literature review, and suggested management

Intestinal pseudo-obstruction is a rare complication resulting from a variety of disorders. Symptoms include abdominal pain, nausea, vomiting, diarrhea, constipation, and malnutrition. Vincristine-related pseudo-obstruction has been reported in the literature, but its description in children and recommendations for management are lacking. A review of the literature revealed 21 reported pediatric cases of vincristine-related pseudo-obstruction. Most have, however, been attributed to a drug interaction with itraconazole, accidental vincristine overdose, or liver failure. Potential genetic causes are rarely addressed. We present here 5 cases of pseudo-obstruction related to vincristine without any identifiable predisposing factors, and a suggested algorithm for management.

Critical illness polyneuropathy: a rare but serious adverse event in pediatric oncology

Critical illness polyneuropathy (CIP) may aggravate sepsis and multiorgan dysfunction in pediatric oncology patients characterized by quadriparesis and difficult weaning from mechanical ventilation. Here, we report on an adolescent patient with acute lymphoblastic T-cell leukemia who developed critical illness neuropathy after an episode of sepsis with need for mechanical ventilation and intravenous catecholamines. Differential diagnoses like vincristine-induced polyneuropathy, anterior lumbosacral radiculopathy (ALR), Guillain-Barré syndrome, and chronic inflammatory demyelinating polyneuropathy - all occurring in pediatric patients with acute leukemia - are discussed.

Vincristine: Can its therapeutic index be enhanced?

Vincristine is one of the most widely used and more effective drugs in paediatric oncology. The dose-limiting toxicity of neuropathy, lack of proven neuroprotective measures and an incomplete understanding of the pharmacokinetics and pharmacogenetics of vincristine have limited its therapeutic potential. Recent advances in the understanding of vincristine pharmacokinetics and pharmacogenetics, and potential methods of preventing neurotoxicity are reviewed which could enable dose escalation and dose individualisation in order to enhance the therapeutic index.

Antifungal prophylaxis with micafungin in patients treated for childhood cancer

BACKGROUND

Invasive fungal infections (IFIs) remain a major cause of infectious morality in neutropenic patients receiving chemotherapy or hematopoietic stem cell transplantation (HSCT). Micafungin exhibits broad antifungal activity against both Aspergillus and Candida species. We performed a retrospective study to determine the efficacy and safety of prophylactic micafungin against IFI in pediatric neutropenic patients during chemotherapy or HSCT.

PROCEDURE

Forty patients were given micafungin (3 mg/kg/day) intravenously for neutropenia: 131 patient-cycles (39 patients) after chemotherapy and 15 patient-cycles (14 patients) after HSCT. Median duration of neutropenia and micafungin prophylaxis was 13 and 23 days after chemotherapy and HSCT, respectively.

RESULTS

Treatment success rate, defined as absence of proven, probable, possible, or suspected IFIs, was 93.9% (121/131) and 80.0% (12/15) for chemotherapy and HSCT, respectively. Proven or probable IFI was documented in only one patient after HSCT. No adverse events were observed that could be related to micafungin prophylaxis.

CONCLUSIONS

These results suggest that prophylactic micafungin is well tolerated and may prevent IFIs in pediatric patients with neutropenia receiving chemotherapy or HSCT.

Analysis of infectious complications in infants with acute lymphoblastic leukemia treated on the Children's Cancer Group Protocol 1953: a report from the Children's Oncology Group

Infants with acute lymphoblastic leukemia have a poor prognosis. The Children's Cancer Group (CCG) 1953 protocol tested the hypothesis that intensification of therapy would improve outcome for these patients. This intensified therapy resulted in better disease control, but resulted in greater toxicity. In this paper, we report the infectious complications associated with this intensified therapy. We retrospectively analyzed the infectious complications reported on the case report forms of all 115 patients enrolled on CCG 1953. Overall 495 infectious complications were identified in 115 patients. Bacterial infections occurred most frequently (74%), followed by viral (13%), fungal (11%), and protozoan (1%). Infection related mortality disproportionately occurred with viral (31%) and fungal (19%) infections. Twenty-three percent (n=26) of patients died of infectious complications, with the majority occurring during induction/intensification. Lower respiratory infections contributed to death in 12 patients and were most commonly viral (n=6) and fungal (n=3). Intensification of therapy resulted in increased infectious complications and deaths compared with previous studies. Future studies will need to focus on: (1) decreasing intensification during the first month of therapy, (2) developing targeted therapies, and (3) improving measures designed to prevent, quickly diagnose, and appropriately treat infections.

Posaconazole-increased vincristine neurotoxicity in a child: a case report

A 9-year-old girl was managed according to the COPRALL 04 protocol for treatment of a relapse of acute lymphoblastic leukemia. Owing to a previous case of disseminated fusariosis, posaconazole was started 5 days before initiation of chemotherapy. Six days after the last dose of vincristine, the child reported symptoms of severe peripheral neuropathy, abdominal cramps, and constipation. After this, she developed fluctuations in her level of consciousness and seizures. After cessation of therapy with posaconazole, a complete resolution of the above occurred within 7 days. This case illustrates the possibility of vincristine toxicity exacerbated by coadministration of posaconazole. As posaconazole is an inhibitor of the isoenzyme CYP3A4, interactions with drugs that are metabolized via this pathway, such as vincristine, can be anticipated. Another possibility is that, like itraconazole, posaconazole may also inhibit P-glycoprotein-mediated vincristine efflux. Although case reports of neurotoxicity owing to possible interaction between itraconazole and vincristine exist in the literature, only 1 case report relating to the possible interaction between posaconazole and vincristine exists. Clinicians should be made aware of this possible drug-drug interaction.

Severe neurotoxicities in a case of Charcot-Marie-Tooth disease type 2 caused by vincristine for acute lymphoblastic leukemia

We report a 13-year-old male patient with Charcot-Marie-Tooth disease (CMT) type 2 who developed severe neuropathy because of vincristine (VCR) for his acute lymphoblastic leukemia. A clumsy gait, muscle weakness in his fingers, and inverted champagne bottlelike muscle in the lower limbs were noticed after remission induction treatment for acute lymphoblastic leukemia, which included VCR at a total dose of 8 mg/m. An electrophysiologic study showed an almost normal median motor nerve conduction velocity (approximately 50 m/s), markedly reduced M-wave amplitude and sensory disturbance. He was diagnosed as CMT type 2 based on his symptoms and electrophysiologic findings. His symptoms gradually worsened, and even after VCR was discontinued, he could not walk alone for 7 months. VCR has previously been considered to be relatively safe in CMT type 2, however, some patients with CMT type 2 might show severe neurologic toxicities, as seen in patients with CMT type 1.

Itraconazole oral solution enhanced vincristine neurotoxicity in five patients with malignant lymphoma

To prevent fungal infections in patients undergoing treatment for hematological malignancies, we investigated the use of oral itraconazole solution as opposed to itraconazole or fluconazole capsules. Herein, we report five lymphoma patients with severe vincristine neurotoxicity in strong association with oral itraconazole solution. Four patients suffered from severe myalgia with or without arthralgia which clinically resembled polymyalgia rheumatica. Two patients suffered from constipation due to subileus and one patient had a severe paralytic ileus. Appropriate management of the above symptoms, which included discontinuation of oral itraconazole solution, resulted in rapid recovery from neurotoxicity. Given the more consistent plasma concentrations of oral itraconazole solution when compared to itraconazole capsules and the ability of itraconazole to interfere with hepatic vincristine metabolism, we strongly recommend avoiding the combined administration of oral itraconazole solution and vincristine.

Life-threatening interaction between antiretroviral therapy and vinblastine in HIV-associated multicentric Castleman's disease

BACKGROUND

HIV-infected patients still present a high risk of developing lymphoproliferative malignancies, despite the fact that their prognosis has been considerably improved by highly active antiretroviral therapy (HAART). Potential interactions exist between antiretroviral drugs, in particular protease inhibitors, and anti-neoplastic ones, but their impact in terms of clinical and haematological adverse events remains unclear.

METHODS

We report a case of potentially life-threatening interaction between vinblastine and antiretroviral therapy in a patient presenting with HIV-associated multicentric Castleman's disease (MCD).

RESULTS

A 55-year-old HIV-1 infected patient was diagnosed with MCD while being treated with a salvage HAART regimen consisting of zidovudine, lamivudine, abacavir, nevirapine and ritonavir-boosted lopinavir. Vinblastine was prescribed as a monotherapy at the usual dose of 6 mg/m2 (i.e. 10 mg) every 3 weeks. The first vinblastine course was performed without HAART with no adverse event. Antiretroviral therapy was resumed for the two following courses which were associated with unexpected severe digestive and haematological toxicities, and moderate renal failure. Vinblastine was then administered alone at increasing doses without toxicity. HAART was finally resumed and we assessed that a decreased vinblastine dose of 2 mg/m2 was well tolerated, with a complete response of MCD.

CONCLUSIONS

HAART regimen comprising protease inhibitors, which are potent inhibitors of cytochrome P450 and P-gp, could interfere with anti-neoplastic drugs, as demonstrated with vinblastine in our case report.