Cerebellar toxicity with high-dose cytosine arabinoside

Effects of D-CAG chemotherapy regimen on cognitive function in patients with acute myeloid leukaemia: A resting-state functional magnetic resonance imaging study

Post-chemotherapy cognitive impairment, also known as 'chemobrain', is a common neurotoxic complication induced by chemotherapy, which has been reported in many cancer survivors who have undergone chemotherapy. In this study, we aimed to explore the effects of D-neneneba dicitabine, C-nenenebb cytarabine, A-aclamycin, G-granulocyte colony-stimulating factor (D-CAG) chemotherapy on cognitive function in patients with acute myeloid leukaemia (AML) and its possible central mechanisms. Twenty patients with AML and 25 matched healthy controls (HC) were enrolled in this study. The cognitive function of patients before and after D-CAG chemotherapy was evaluated by the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog). The resting-state functional magnetic resonance imaging data were collected from all patients before and after chemotherapy intervention, as well as HC. Then, resting-state functional magnetic resonance imaging data were preprocessed using DPABI software package and regional homogeneity (ReHo) values of brain regions were calculated. Finally, ReHo values between groups were compared by Resting-State fMRI Data Analysis software package with t-tests and Alphasim method was performed for multiple comparison correction. Moreover, associations between ReHo values of altered brain regions and the scores of FACT-Cog were analysed by Pearson correlation. The total FACT-Cog scores and four factor scores of AML patients increased significantly after treatment. ReHo values showed no significant changes in patients before treatment when compared with HC. Compared with HC, ReHo values of the right middle frontal gyrus, inferior frontal gyrus (opercular part), middle occipital gyrus, and left praecuneus decreased significantly, while ReHo values of the left inferior temporal gyrus, right middle temporal gyrus, and hippocampus increased significantly in patients after treatment. Compared with patients before treatment, ReHo values decreased significantly in the right middle frontal gyrus, inferior frontal gyrus (opercular part), and middle and inferior occipital gyri of patients after treatment. In addition, ReHo values of the right inferior frontal gyrus (opercular part) were negatively correlated with the total scores of FACT-Cog and factor scores of perceived cognitive impairment in patients after treatment. There were also negative correlations between ReHo values of the right middle frontal gyrus and perceived cognitive impairment scores. The present study confirmed that D-CAG chemotherapy might cause impaired subjective self-reported cognitive functioning in AML patients, which might be related to the decreased function of certain regions in the right prefrontal lobe. These findings provided further understanding of the mechanisms involved in post-chemotherapy cognitive impairment and would help develop new therapeutic strategies for 'chemobrain' in AML patients.

AraC interacts with p75NTR transmembrane domain to induce cell death of mature neurons

Cytosine arabinoside (AraC) is one of the main therapeutic treatments for several types of cancer, including acute myeloid leukaemia. However, after a high-dose AraC chemotherapy regime, patients develop severe neurotoxicity and cell death in the central nervous system leading to cerebellar ataxia, dysarthria, nystagmus, somnolence and drowsiness. AraC induces apoptosis in dividing cells. However, the mechanism by which it leads to neurite degeneration and cell death in mature neurons remains unclear. We hypothesise that the upregulation of the death receptor p75^NTR is responsible for AraC-mediated neurodegeneration and cell death in leukaemia patients undergoing AraC treatment. To determine the role of AraC-p75^NTR signalling in the cell death of mature neurons, we used mature cerebellar granule neurons' primary cultures from p75^NTR knockout and p75^NTRCys259 mice. Evaluation of neurite degeneration, cell death and p75^NTR signalling was done by immunohistochemistry and immunoblotting. To assess the interaction between AraC and p75^NTR, we performed cellular thermal shift and AraTM assays as well as Homo-FRET anisotropy imaging. We show that AraC induces neurite degeneration and programmed cell death of mature cerebellar granule neurons in a p75^NTR-dependent manner. Mechanistically, Proline 252 and Cysteine 256 residues facilitate AraC interaction with the transmembrane domain of p75^NTR resulting in uncoupling of p75^NTR from the NFκB survival pathway. This, in turn, exacerbates the activation of the cell death/JNK pathway by recruitment of TRAF6 to p75^NTR. Our findings identify p75^NTR as a novel molecular target to develop treatments for counteract AraC-mediated cell death of mature neurons.

Role of inflammation and oxidative stress in chemotherapy-induced neurotoxicity

Chemotherapeutic agents may adversely affect the nervous system, including the neural precursor cells as well as the white matter. Although the mechanisms are not completely understood, several hypotheses connecting inflammation and oxidative stress with neurotoxicity are now emerging. The proposed mechanisms differ depending on the class of drug. For example, toxicity due to cisplatin occurs due to activation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), which alters hippocampal long-term potentiation. Free radical injury is also involved in the cisplatin-mediated neurotoxicity as dysregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) has been seen which protects against the free radical injury by regulating glutathione S-transferases and hemeoxygenase-1 (HO-1). Thus, correcting the imbalance between NF-κB and Nrf2/HO-1 pathways may alleviate cisplatin-induced neurotoxicity. With newer agents like bortezomib, peripheral neuropathy occurs due to up-regulation of TNF-α and IL-6 in the sensory neurons. Superoxide dismutase dysregulation is also involved in bortezomib-induced neuropathy. This article reviews the available literature on inflammation and oxidative stress in neurotoxicity caused by various classes of chemotherapeutic agents. It covers the conventional medicines like platinum compounds, vinca alkaloids, and methotrexate, as well as the newer therapeutic agents like immunomodulators and immune checkpoint inhibitors. A better understanding of the pathophysiology will lead to further advancement in strategies for management of chemotherapy-induced neurotoxicity.

Neurocognitive deficits in survivors of childhood acute myeloid leukemia

BACKGROUND

Although treatment of acute myeloid leukemia (AML) contains neurotoxic agents, studies investigating neurocognitive outcomes in children with AML are sparse. We evaluated late cognitive effects in children treated with a high-dose cytarabine based regimen, focusing on general intellectual ability and specific neurocognitive domains.

METHODS

We evaluated 12 survivors of childhood AML who were treated between 2006 and 2016 and completed the Wechsler Intelligence Scales. One-sample t-tests were used to compare full-scale intelligence quotient (FSIQ) and primary index scores to norms. The overall effect of index scores and subtests was examined with one-way ANOVA. Univariate analyses and multiple regression models examined demographic and clinical characteristics associated with FSIQ.

RESULTS

Participants who underwent the Wechsler Intelligence Scale for Children demonstrated impairment on working memory index and participants who underwent the Wechsler Adult Intelligence Scale showed low score in the subtests that reflect working memory, whereas they exhibited no statistical differences versus the population means for FSIQ. There were no significant differences in the overall effect of index scores and subtests. On univariate analysis, FSIQ were related to time since diagnosis and age at assessment, and both were significant predictors of FSIQ on multiple linear regression.

CONCLUSIONS

Survivors of childhood AML exhibited impairment of working memory, even if their FSIQ was within the normal range. Difficulties in specific cognitive domains are associated with reduced quality of life. It is important to identify survivors who are at risk and provide tailored interventions.

Retreatment with full-dose cytarabine in a patient with previous neurological toxicity

INTRODUCTION

Cytarabine is one of the main chemotherapy drugs used to treat hematological malignancies. Neurotoxicity is an increasingly recognized adverse effect of high-dose cytarabine therapy and occurs in 10% to 25% of patients. There is very little experience with cytarabine retreatment following neurotoxicity.

CASE REPORT

We report a case of a man who was diagnosed with chemotherapy-induced cerebellar syndrome. He was treated with high doses of cytarabine.

MANAGEMENT AND OUTCOME

The patient was successfully retreated at full dose after experiencing cytarabine-induced cerebellar toxicity during the first cycle of a chemotherapy regimen. He did not develop any neurological complications and successfully underwent hematopoietic stem cell transplantation. He is currently in complete remission and free of disease.

DISCUSSION

This original case report assesses the possibility of retreatment without the need for dose reduction.

MRD negative CR after azacitidine and venetoclax in a young patient with AML, unfit for intensive induction followed by ASCT

A subset of AML patients are unfit for 7+3 induction at the time of diagnosis. Present case highlights the use of azacitidine and venetoclax in a patient with intermediate risk AML with WT-1 mutation,deemed unfit for intensive induction in view of poor general condition and comorbid illness. After venetoclax and azacitidine patient was negative for measurable residual disease but developed cerebellar toxicity after high dose cytarabine. He underwent successful matched sibling allogeneic stem cell transplant and is presently on routine follow up. This case report suggest possible role of this combination even in young patients unfit for intensive induction.

Consolidation in AML: Abundant opinion and much unknown

Consolidation therapy forms the backbone of post-remission therapy for AML and is uniformly accepted as an integral part of therapy designed to achieve long-term survival. The need for post-remission therapy was initially described over four decades ago and has since undergone many variations in terms of dosage, number of cycles and intensity of therapy. There is much empiricism in the current understanding of consolidation therapy and much that has not been rigorously studied. This review will consider the many aspects of consolidation therapy, focusing on the number of cycles, differences between young and older adults, first and subsequent remission as well as therapy prior to an allogeneic transplant. Emphasis will be given to differentiate strategies that are clearly evidence-based from those that have been incorporated into standard of care while bypassing the need for rigorous data-driven approaches. Finally, consideration will be given to the current ability to assess the minimal measureable residual disease and the impact that this may have on therapeutic paradigms, including superseding many of the time-honored prognostic features.

Response and Toxicity to Cytarabine Therapy in Leukemia and Lymphoma: From Dose Puzzle to Pharmacogenomic Biomarkers

Simple Summary

In this review, the authors propose a crosswise examination of cytarabine-related issues ranging from the spectrum of clinical activity and severe toxicities, through updated cellular pharmacology and drug formulations, to the genetic variants associated with drug-induced phenotypes. Cytarabine (cytosine arabinoside; Ara-C) in multiagent chemotherapy regimens is often used for leukemia or lymphoma treatments, as well as neoplastic meningitis. Chemotherapy regimens can induce a suboptimal clinical outcome in a fraction of patients. The individual variability in clinical response to Leukemia & Lymphoma treatments among patients appears to be associated with intracellular accumulation of Ara-CTP due to genetic variants related to metabolic enzymes. The review provides exhaustive information on the effects of Ara-C-based therapies, the adverse drug reaction will also be provided including bone pain, ocular toxicity (corneal pain, keratoconjunctivitis, and blurred vision), maculopapular rash, and occasional chest pain. Evidence for predicting the response to cytarabine-based treatments will be highlighted, pointing at their significant impact on the routine management of blood cancers.

Abstract

Cytarabine is a pyrimidine nucleoside analog, commonly used in multiagent chemotherapy regimens for the treatment of leukemia and lymphoma, as well as for neoplastic meningitis. Ara-C-based chemotherapy regimens can induce a suboptimal clinical outcome in a fraction of patients. Several studies suggest that the individual variability in clinical response to Leukemia & Lymphoma treatments among patients, underlying either Ara-C mechanism resistance or toxicity, appears to be associated with the intracellular accumulation and retention of Ara-CTP due to genetic variants related to metabolic enzymes. Herein, we reported (a) the latest Pharmacogenomics biomarkers associated with the response to cytarabine and (b) the new drug formulations with optimized pharmacokinetics. The purpose of this review is to provide readers with detailed and comprehensive information on the effects of Ara-C-based therapies, from biological to clinical practice, maintaining high the interest of both researcher and clinical hematologist. This review could help clinicians in predicting the response to cytarabine-based treatments.

Repurposing Clinical Agents for Chemical Exchange Saturation Transfer Magnetic Resonance Imaging: Current Status and Future Perspectives

Molecular imaging is becoming an indispensable tool to pursue precision medicine. However, quickly translating newly developed magnetic resonance imaging (MRI) agents into clinical use remains a formidable challenge. Recently, Chemical Exchange Saturation Transfer (CEST) MRI is emerging as an attractive approach with the capability of directly using low concentration, exchangeable protons-containing agents for generating quantitative MRI contrast. The ability to utilize diamagnetic compounds has been extensively exploited to detect many clinical compounds, such as FDA approved drugs, X-ray/CT contrast agents, nutrients, supplements, and biopolymers. The ability to directly off-label use clinical compounds permits CEST MRI to be rapidly translated to clinical settings. In this review, the current status of CEST MRI based on clinically available compounds will be briefly introduced. The advancements and limitations of these studies are reviewed in the context of their pre-clinical or clinical applications. Finally, future directions will be briefly discussed.

Complications and Toxicities Associated with Cancer Therapies in the Intensive Care Unit

Advances in the management of hematologic malignancies and solid tumors have given rise to diverse modalities to treat cancer other than cytotoxic chemotherapy, including targeted therapies, immunotherapies, and cellular therapies. Currently, there are over 175 FDA-approved antineoplastic agents in the United States, many with a diverse and profound toxicity profile. Complications of antineoplastic therapy may result in the need for intensive care unit (ICU) admission to provide acute symptom management. Accordingly, ICU providers caring for cancer patients should have a working knowledge of the toxicities and complications associated with antineoplastic therapy.

Central nervous system emergencies in haematological malignancies

Neurological emergencies are frequently catastrophic events in the course of haematological malignancies (HM) that, if not promptly recognized and treated, may lead to lethal outcomes or chronic sequelae. They may occur at any time during the disease course, but are more frequently observed following relapse. Practice guidelines are lacking in the management of most central nervous system (CNS) complications in HM. Herein we review the pathophysiology, presentation and treatment of elevated intracranial pressure, spinal cord compression, status epilepticus, neurovascular complications, CNS infection, leucostasis and hyperviscosity. Further, we discuss the expanding spectrum of neurological complications of old and novel treatments in HM.

Advances in risk assessment and prophylaxis for central nervous system relapse in diffuse large B-cell lymphoma

Central nervous sytem recurrence of diffuse large B-cell lymphoma is an uncommon but devastating event, making identification of patients at high risk for relapse within the central nervous system essential for clinicians. Modern risk stratification includes both clinical and biological features. A validated clinical risk model employing the five traditional International Prognostic Index risk factors plus renal or adrenal involvement can identify a high-risk patient population with a central nervous system recurrence risk of greater than 10%. Lymphoma involvement of certain discrete extranodal sites such as the testis also confers increased risk, even in stage I disease. Adverse biological risk factors for central nervous system relapse include presence of translocations of MYC, BCL2 and/or BCL6, in so-called double- or triple-hit lymphoma. Immunohistochemically detectable co-expression of MYC and BCL2 in the absence of translocations also portends an increased risk of relapse within the central nervous system, particularly in the setting of the activated B-cell-like subtype of diffuse large B-cell lymphoma. The role, method, and timing of prophylactic therapy remain controversial based on the available data. We review both intrathecal and systemic strategies for prophylaxis in high-risk patients. Our preference is for systemic methotrexate in concert with standard chemoimmunotherapy in the majority of cases. Several novel agents have also demonstrated clinical activity in primary and secondary central nervous system lymphoma and warrant future investigation in the prophylactic setting.

Intensive Combination Immunotherapy and Neuroinflammation Resolution in a Child With Anti-PCA-1 (Yo) Paraneoplastic Syndrome and 2 Malignancies

Paraneoplastic cerebellar degeneration is rare and noteworthy in children. In this 7-year-old, it was documented to have occurred within a year of ataxia presentation. The instigating cancer was stage III adrenal adenocarcinoma, remitted after surgical resection at age 2. When her severe ataxia progressed, neuroinflammation was characterized by high cerebrospinal fluid Purkinje cell cytoplasmic antibody type 1 titers, oligoclonal bands, and neurofilament light chain. The immunotherapy strategy was to replace IV methylprednisolone, which lowered Purkinje cell cytoplasmic antibody type 1 titers without clinical improvement, with induction of adrenocorticotropic hormone/intravenous immunoglobulin/rituximab (ACTH/IVIG/rituximab) combination immunotherapy, ACTH/dexamethasone transition, and intravenous immunoglobulin maintenance. She became self-ambulatory and cerebrospinal fluid inflammatory markers regressed. Down syndrome predisposed her to a second cancer, pre-B acute lymphoblastic leukemia, 4 years later. Despite reversible cytosine arabinoside-provoked cerebellar toxicity, the ataxia is stable on monthly intravenous immunoglobulin without relapse, now 5 years after initial diagnosis. This report illustrates the use of cerebrospinal fluid biomarkers to detect, target, and monitor neuroinflammation, and successful combinations of immunotherapy to better the quality of life.

Neurological Complications of the Treatment of Pediatric Neoplastic Disorders

Neurological complications resulting from childhood cancer treatments are common. Treatment for childhood neoplastic disorders is often multimodal and may include procedures, cranial irradiation, chemotherapy, transplant, and immunotherapy, each of which carries distinct neurological risks. Procedures, such as lumbar punctures, are commonly used in this population for diagnostic purposes as well as intrathecal medication administration. Surgery is associated with an array of potential neurological complications, with posterior fossa syndrome being a common cause of morbidity in pediatric brain tumor patients after neurosurgical resection. Cranial irradiation can cause late neurological sequelae such as stroke, cerebral vasculopathy, secondary malignancy, and cognitive dysfunction. Neurotoxic effects of chemotherapeutic agents are common and include neuropathy, coagulopathy causing stroke or cerebral sinovenous thrombosis, encephalopathy, seizures, cerebellar dysfunction, myelopathy, and neuropsychologic difficulties. Hematopoietic stem cell transplant has a high risk of neurological complications including central nervous system infection, seizures, and stroke. Immunotherapies, including chimeric antigen receptor-modified T-cells (CAR T-cells) and immune checkpoint inhibitors, are emerging as potentially effective strategies to treat some types of childhood cancer, but may carry with them substantial neurotoxicity which is just beginning to be recognized and studied. With evolving treatment protocols, childhood cancer survivorship is increasing, and the role of the neurologist in managing both the acute and chronic neurological consequences of treatment is becoming more important. Prevention, early recognition, and treatment of therapy-associated neurotoxicity are imperative to ensuring children can remain on the most effective therapeutic regimens and to improve the neurological function and quality of life of childhood cancer survivors.

A phase I study of selinexor in combination with high-dose cytarabine and mitoxantrone for remission induction in patients with acute myeloid leukemia

BACKGROUND

Novel therapies for patients with acute myeloid leukemia (AML) are imperative, particularly for those with high-risk features. Selinexor, an exportin 1 (XPO1/CRM1) inhibitor, has demonstrated anti-leukemia activity as a single agent, as well as in combination with anthracyclines and/or DNA-damaging agents.

METHODS

We report the findings of a phase I dose escalation trial with cohort expansion in 20 patients with newly diagnosed or relapsed/refractory AML that combined selinexor with age-adjusted high-dose cytarabine and mitoxantrone (HiDAC/Mito).

RESULTS

Three (15%) patients received the initial dose of 60 mg of selinexor (~ 35 mg/m2), and 17 (85%) received the target level of 80 mg (~ 50 mg/m2). No dose-limiting toxicities were observed. Common adverse events included febrile neutropenia (70%), diarrhea (40%), anorexia (30%), electrolyte abnormalities (30%), bacteremia (25%), cardiac toxicities (25%), fatigue (25%), and nausea/vomiting (25%). None were unexpected given the HiDAC/Mito regimen. Serious adverse events occurred in 6 (30%) patients; one was fatal. Ten (50%) patients achieved a complete remission (CR), 3 (15%) achieved CR with incomplete recovery (CRi), 1 (5%) achieved partial remission (PR), and 6 (30%) had progressive disease for an overall response rate (ORR) of 70%. Eight of 14 (57%) responders proceeded to allogeneic stem cell transplantation. Correlative studies of WT1 levels showed persistently detectable levels in patients who either did not respond or relapsed quickly after induction.

CONCLUSION

The selinexor/HiDAC/Mito regimen is feasible and tolerable at selinexor doses of 80 mg/day (~ 50 mg/m2/day) twice weekly. The recommended phase II dose is 80 mg and warrants further study in this combination.

TRIAL REGISTRATION

ClinicalTrials.gov , NCT02573363 . Registered October 5, 2015.

Management of neuro-oncologic emergencies

Patients with brain tumors and systemic malignancies are subject to diverse neurologic complications that require urgent evaluation and treatment. These neurologic conditions are commonly due to the tumor's direct effects on the nervous system, such as cerebral edema, increased intracranial pressure, seizures, spinal cord compression, and leptomeningeal metastases. In addition, neurologic complications can develop as a result of thrombocytopenia, coagulopathy, hyperviscosity syndromes, infection, immune-related disorders, and adverse effects of treatment. Patients may present with typical disease syndromes. However, it is not uncommon for patients to have more subtle, nonlocalizing manifestations, such as alteration of mental status, that could be attributed to other systemic, nonneurologic complications. Furthermore, neurologic complications are at times the initial manifestations of an undiagnosed malignancy. Therefore a high index of suspicion is essential for rapid assessment and management. Timely intervention may prolong survival and improve quality of life. In this chapter, we will discuss the common neuro-oncologic emergencies, including epidemiology, pathophysiology, clinical presentation, diagnosis, and treatment.

Safety Assessment of 4′-Thio-β-d-Arabinofuranosylcytosine in the Beagle Dog Suggests a Drug-Induced Centrally Mediated Effect on the Hypothalamic-Pituitary-Adrenal Axis

4′-Thio- β-d-arabinofuranosylcytosine (OSI-7836) is a nucleoside analogue with structural similarity to gemcitabine and cytarabine (ara-C). Myelosuppression, reversible transaminase elevations, and flu-like symptoms are common side effects associated with human use of gemcitabine and ara-C. Fatigue is also associated with the use of gemcitabine and OSI-7836 in humans. To better understand the toxicity of OSI-7836, subchronic studies were conducted in dogs. OSI-7836 was administered on days 1 and 8 or on days 1, 2, and 3 of a 21-day dose regimen. These schedules attempted to match clinical trial dosing regimens. Routine toxicity study end points demonstrated that OSI-7836 was primarily cytotoxic to the gastrointestinal tract, bone marrow, and testes; the myelotoxicity was mild and reversible. Plasma pharmacokinetics were dose-linear with an elimination half-life of 2.2 h. Follow-up single dose experiments in dogs assessed drug effects on lymphocyte subpopulations and on adrenal and thyroid function. Populations of T and B cells were equally reduced following OSI-7836 administration. There were no adverse effects on thyroid function, but there were marked reductions in circulating cortisol and adrenocorticotropic hormone concentrations suggesting a centrally mediated impairment of the hypothalamic-pituitary-adrenal axis. These findings show a toxicological profile with OSI-7836 similar to other nucleoside analogues and suggest that the beagle is a model for studying one possible cause of OSI-7836-related fatigue, impaired function of the hypothalamic-pituitary-adrenal axis.

Cancer-treatment-induced neurotoxicity--focus on newer treatments

Neurotoxicity caused by traditional chemotherapy and radiotherapy is widely recognized in patients with cancer. The adverse effects of newer therapeutics, such as biological and immunotherapeutic agents, are less well established, and are associated with considerable neurotoxicity in the central and peripheral nervous systems. This Review addresses the main neurotoxicities of cancer treatment with a focus on the newer therapeutics. Recognition of these patterns of toxicity is important because drug discontinuation or dose adjustment might prevent further neurological injury. Knowledge of these toxicities also helps to differentiate treatment-related symptoms from progression of cancer or its involvement of the nervous system. Familiarity with the neurological syndromes associated with cancer treatments enables clinicians to use the appropriate treatment for the underlying malignancy while minimizing the risk of neurological damage, which might preserve patients' quality of life.

Pharmacodynamics of cytarabine induced leucopenia: a retrospective cohort study

AIMS

Cytarabine is a pyrimidine analogue used to treat a variety of haematological malignancies. There are few data regarding the pharmacodynamics of cytarabine. The only publications regarding this issue cite a biphasic pattern of decline in white blood cell (WBC) counts following low and intermediate doses, in patients with various malignancies, most of them non-haematological. Our purpose was to establish the pharmacodynamics of cytarabine induced leucopenia in acute myeloid leukaemia (AML) patients treated with contemporary cytarabine containing protocols.

METHODS

We conducted a retrospective cohort study, including 56 patients with AML in complete remission who had received 89 cycles of intermediate or high dose cytarabine. Daily counts for WBCs and neutrophils (ANC) were collected during the first 15 days after the initiation of cytarabine administration and pharmacodynamics were analyzed. Further analysis was carried out to correlate between WBC and ANC pharmacodynamics and different cytarabine protocols [high dose cytarabine (HiDAC) vs. intermediate dose cytarabine (IDAC)].

RESULTS

Analysis of blood counts demonstrated a monophasic decline of WBCs and ANCs, unlike a previous depiction of a biphasic pattern. HiDAC was associated with a significantly sharper decline of WBCs than IDAC.

CONCLUSIONS

Our data support a monophasic decline pattern of WBCs and ANCs following contemporary cytarabine protocols. The decline rate is steeper for patients receiving HiDAC than for those receiving IDAC. These results might help form evidence based guidelines regarding patient monitoring intensity, timing of prophylactic antibacterial and antifungal treatment as well as growth factors' support following cytarabine based consolidation for AML.

Redox biology in normal cells and cancer: restoring function of the redox/Fyn/c-Cbl pathway in cancer cells offers new approaches to cancer treatment

This review discusses a unique discovery path starting with novel findings on redox regulation of precursor cell and signaling pathway function and identification of a new mechanism by which relatively small changes in redox status can control entire signaling networks that regulate self-renewal, differentiation, and survival. The pathway central to this work, the redox/Fyn/c-Cbl (RFC) pathway, converts small increases in oxidative status to pan-activation of the c-Cbl ubiquitin ligase, which controls multiple receptors and other proteins of central importance in precursor cell and cancer cell function. Integration of work on the RFC pathway with attempts to understand how treatment with systemic chemotherapy causes neurological problems led to the discovery that glioblastomas (GBMs) and basal-like breast cancers (BLBCs) inhibit c-Cbl function through altered utilization of the cytoskeletal regulators Cool-1/βpix and Cdc42, respectively. Inhibition of these proteins to restore normal c-Cbl function suppresses cancer cell division, increases sensitivity to chemotherapy, disrupts tumor-initiating cell (TIC) activity in GBMs and BLBCs, controls multiple critical TIC regulators, and also allows targeting of non-TICs. Moreover, these manipulations do not increase chemosensitivity or suppress division of nontransformed cells. Restoration of normal c-Cbl function also allows more effective harnessing of estrogen receptor-α (ERα)-independent activities of tamoxifen to activate the RFC pathway and target ERα-negative cancer cells. Our work thus provides a discovery strategy that reveals mechanisms and therapeutic targets that cannot be deduced by standard genetics analyses, which fail to reveal the metabolic information, isoform shifts, protein activation, protein complexes, and protein degradation critical to our discoveries.

Drug-induced cerebellar ataxia: a systematic review

BACKGROUND AND OBJECTIVES

Cerebellar ataxia can be induced by a large number of drugs. We here conducted a systemic review of the drugs that can lead to cerebellar ataxia as an adverse drug reaction (ADR).

METHODS

We performed a systematic literature search in Pubmed (1966 to January 2014) and EMBASE (1988 to January 2014) to identify all of the drugs that can have ataxia as an ADR and to assess the frequency of drug-induced ataxia for individual drugs. Furthermore, we collected reports of drug-induced ataxia over the past 20 years in the Netherlands by querying a national register of ADRs.

RESULTS

Drug-induced ataxia was reported in association with 93 individual drugs (57 from the literature, 36 from the Dutch registry). The most common groups were antiepileptic drugs, benzodiazepines, and antineoplastics. For some, the number needed to harm was below 10. Ataxia was commonly reversible, but persistent symptoms were described with lithium and certain antineoplastics.

CONCLUSIONS

It is important to be aware of the possibility that ataxia might be drug-induced, and for some drugs the relative frequency of this particular ADR is high. In most patients, symptoms occur within days or weeks after the introduction of a new drug or an increase in dose. In general, ataxia tends to disappear after discontinuation of the drug, but chronic ataxia has been described for some drugs.

The double-edged sword: Neurotoxicity of chemotherapy

The number of available therapies for hematologic malignancies continues to grow at a rapid pace. Unfortunately, many of these treatments carry both central and peripheral nervous system toxicities, potentially limiting a patient's ability to tolerate a full course of treatment. Neurotoxicity with chemotherapy is common and second only to myelosuppression as a reason to limit dosing. This review addresses the neurotoxicity of newly available therapeutic agents including brentuximab vedotin and blinatumomab as well as classic ones such as methotrexate, vinca alkaloids and platinums. Although peripheral neuropathy is common with many drugs, other complications such as seizures and encephalopathy may require more immediate attention. Rapid recognition of adverse neurologic effects may lead to earlier treatment and appropriate adjustment of dosing regimens. In addition, knowledge of common toxicities may help differentiate chemotherapy-related symptoms from actual progression of cancer into the CNS.

Iatrogenic neurology

Iatrogenic disease is one of the most frequent causes of hospital admissions and constitutes a growing public health problem. The most common type of iatrogenic neurologic disease is pharmacologic, and the central and peripheral nervous systems are particularly vulnerable. Despite this, iatrogenic disease is generally overlooked as a differential diagnosis among neurologic patients. The clinical picture of pharmacologically mediated iatrogenic neurologic disease can range from mild to fatal. Common and uncommon forms of drug toxicity are comprehensively addressed in this chapter. While the majority of neurologic adverse effects are listed and referenced in the tables, the most relevant issues are further discussed in the text.

Uptake carriers and oncology drug safety

Members of the solute carrier (SLC) family of transporters are responsible for the cellular influx of a broad range of endogenous compounds and xenobiotics in multiple tissues. Many of these transporters are highly expressed in the gastrointestinal tract, liver, and kidney and are considered to be of particular importance in governing drug absorption, elimination, and cellular sensitivity of specific organs to a wide variety of oncology drugs. Although the majority of studies on the interaction of oncology drugs with SLC have been restricted to the use of exploratory in vitro model systems, emerging evidence suggests that several SLCs, including OCT2 and OATP1B1, contribute to clinically important phenotypes associated with those agents. Recent literature has indicated that modulation of SLC activity may result in drug-drug interactions, and genetic polymorphisms in SLC genes have been described that can affect the handling of substrates. Alteration of SLC function by either of these mechanisms has been demonstrated to contribute to interindividual variability in the pharmacokinetics and toxicity associated with several oncology drugs. In this report, we provide an update on this rapidly emerging field.

Optimization of cytarabine (ARA-C) therapy for acute myeloid leukemia

Cytarabine (cytosine arabinoside) is one of the most effective drugs for the treatment of acute myeloid leukemia. The standard dose of cytarabine used to treat this leukemia is 100 mg per square meter. In an attempt to improve the effectiveness of cytarabine against acute myeloid leukemia, a high-dose treatment (3,000 mg per square meter) was introduced into therapy. The side effects of high-dose cytarabine was a major concern, especially its neurological toxicity. A review of recent clinical trials indicates that this high-dose cytarabine can be replaced by the intermediate-dose of 1,000 mg per square meter without loss of efficacy and with less toxicity. This is an important step to improve the efficacy of cytarabine for the treatment of acute myeloid leukemia. Despite the improvements in the therapy for this leukemia, the current overall survival rate for adult patients is less than 30%. To optimize the cytarabine therapy, it is important to determine how some leukemic stem cells survive treatment. Preclinical data suggest that survival of the leukemic stem cells could be due to the long 12 hour interval between infusions of cytarabine, which permits some leukemic cells to escape its S phase specific action. Among the other factors that can lead to leukemic cell survival are the high levels in the liver and spleen of cytidine deaminase, the enzyme that inactivates cytarabine and drug resistance due to deficiency in deoxycytidine kinase, the enzyme that activates the prodrug, cytarabine. Several approaches are proposed in this commentary to overcome these impediments with the goal of increasing the effectiveness of cytarabine for the treatment of acute myeloid leukemia.

How I treat hematologic emergencies in adults with acute leukemia

Acute myeloid leukemia and acute lymphoblastic leukemia remain devastating diseases. Only approximately 40% of younger and 10% of older adults are long-term survivors. Although curing the leukemia is always the most formidable challenge, complications from the disease itself and its treatment are associated with significant morbidity and mortality. Such complications, discussed herein, include tumor lysis, hyperleukocytosis, cytarabine-induced cellebellar toxicity, acute promyelocytic leukemia differentiation syndrome, thrombohemorrhagic syndrome in acute promyelocytic leukemia, L-asparaginase-associated thrombosis, leukemic meningitis, neutropenic fever, neutropenic enterocolitis, and transfussion-associated GVHD. Whereas clinical trials form the backbone for the management of acute leukemia, emergent clinical situations, predictable or not, are common and do not readily lend themselves to clinical trial evaluation. Furthermore, practice guidelines are often lacking. Not only are prospective trials impractical because of the emergent nature of the issue at hand, but clinicians are often reluctant to randomize such patients. Extensive practical experience is crucial and, even if there is no consensus, management of such emergencies should be guided by an understanding of the underlying pathophysiologic mechanisms.

Central nervous system chemotoxicity during treatment of pediatric acute lymphoblastic leukemia/lymphoma

In the last decades, increasing success rates are being obtained in the chemotherapy of pediatric leukemia and lymphoma. However, the cornerstone of this treatment is still formed by a reduced number of drugs with a highly toxic profile. In particular, central nervous system complications remain a challenging clinical problem, requiring rapid detection and prompt treatment to limit permanent damage. Furthermore, clinicians are often challenged to discriminate between CNS involvement by the disease, toxicity of drugs or infections. This clinically oriented review will help recognize and handle the main neurologic adverse effects induced by chemotherapy in pediatric patients with lymphoblastic leukemia/lymphoma. Different clinical entities and putative drugs involved are discussed in each chapter, with clinical cases illustrating the most relevant and challenging events. In addition, specific clinical-radiological patterns of some of these neurologic events are detailed. Finally, the role of pharmacogenetics, with special focus on those polymorphisms that could help explain the occurrence of neurotoxicity, is also discussed.

Toxic agents causing cerebellar ataxias

The cerebellum is particularly vulnerable to intoxication and poisoning, especially so the cerebellar cortex and Purkinje neurons. In humans, the most common cause of a toxic lesion to the cerebellar circuitry is alcohol related, but the cerebellum is also a main target of drug exposure (such as anticonvulsants, antineoplastics, lithium salts, calcineurin inhibitors), drug abuse and addiction (such as cocaine, heroin, phencyclidine), and environmental toxins (such as mercury, lead, manganese, toluene/benzene derivatives). Although data for the prevalence and incidence of cerebellar lesions related to intoxication and poisoning are still unknown in many cases, clinicians should keep in mind the list of agents that may cause cerebellar deficits, since toxin-induced cerebellar ataxias are not rare in daily practice. Moreover, the patient's status may require immediate therapies when the intoxication is life-threatening.

Brain perfusion in adult patients with acute myeloblastic leukemia before and after cytosine arabinoside

PURPOSE

High-dose (HD) cytosine arabinoside (ara-C) is a major treatment in acute myeloblastic leukemia (AML) that can lead to cerebellar complications, although electroencephalogram, computed tomography, and magnetic resonance imaging remain normal. We conducted a prospective study to evaluate brain perfusion with single-photon emission computed tomography (SPECT) in adult patients before and after receiving ara-C.

PROCEDURES

Forty-three patients were pre-included, and 20 reached a complete remission. These 20 patients were definitively included and underwent three technetium-99m hexamethyl-propylene-amine oxime (HMPAO) SPECT acquisitions with a double-head camera: SPECT1 at AML diagnosis, SPECT2 after induction (conventional ara-C dose), and SPECT3 during HD ara-C treatment. All the included patients underwent six series of neurological and cognitive examinations: N1, N2, and N3 at the time of SPECT1, SPECT2, and SPECT3, respectively; N4 during HD ara-C treatment; N5 (at 10 days); and N6 during follow-up (at 6 months). Statistical parametric mapping (SPM2) was used to test perfusion changes. A specific method based on random walk (RW) was used to analyze diffuse brain perfusion heterogeneity.

RESULTS

No neurological adverse effect was observed, and all neurological and cognitive examinations remained normal. Between SPECT1 and SPECT2, SPM2 analysis showed a decrease in cerebral blood flow, i.e., in the cerebellum, in the occipitoparietal cortex, and in the thalamus. No significant difference was observed between SPECT2 and SPECT3 or between SPECT1 and SPECT3. RW analysis showed no significant difference in perfusion heterogeneity between the three SPECTs.

CONCLUSIONS

HMPAO SPECT demonstrated a decrease in thalamus, cerebellar, and parieto-occipital perfusion after conventional doses of ara-C in AML patients, although the neurological examinations were normal and the patients had no neurological adverse effects.

Neurotoxicity of cancer treatment

Cancer therapy--including brain-directed surgery, brain or spine irradiation, or chemotherapy--may affect the nervous system in a deleterious manner, affecting either the central or peripheral nervous systems. The causation of encephalopathy (eg, radiation, chemotherapy) is most relevant for the differential diagnosis of central nervous system (CNS) disorders, as defining a specific cause determines further treatment and outcome. Peripheral nervous system disorders (ie, steroid myopathy, spindle poison, or platinum neuropathy) are predominantly treatment related and respond best to discontinuation of the neurotoxic agent.

Anticancer activity test for extracts of Sarang semut plant (Myrmecodya pendens) to HeLa and MCM-B2 cells

The aim of this study is to investigate anticancer activity of methanol extract (ethylacetate, n-buthanol and water partitions) and water extract from Sarang semut (local name), Myrmecodya pendens which is one of Rubiaceae family. Within Papua area (Indonesia), this medicinal plant has been used traditionally as alternative treatment for ulcer, tumor and cancer. In this study, the extracts of this plant were tested for their activities in some cancer cells (HeLa and MCM-B2 cell). The result showed that water extract of this plant has better anti cancer activity compared to other extracts. The IC50 value of water extract A is 27.61 ppm (HeLa) and 54.57 ppm (MCM-B2), while water extract B is 29.36 ppm (HeLa) and 74.20 ppm (MCM-B2). Our study concluded that polar extract (water) exhibited higher anticancer activity than non-polar extracts (ethylacetate and n-buthanol).

Systemic 5-fluorouracil treatment causes a syndrome of delayed myelin destruction in the central nervous system

BACKGROUND

Cancer treatment with a variety of chemotherapeutic agents often is associated with delayed adverse neurological consequences. Despite their clinical importance, almost nothing is known about the basis for such effects. It is not even known whether the occurrence of delayed adverse effects requires exposure to multiple chemotherapeutic agents, the presence of both chemotherapeutic agents and the body's own response to cancer, prolonged damage to the blood-brain barrier, inflammation or other such changes. Nor are there any animal models that could enable the study of this important problem.

RESULTS

We found that clinically relevant concentrations of 5-fluorouracil (5-FU; a widely used chemotherapeutic agent) were toxic for both central nervous system (CNS) progenitor cells and non-dividing oligodendrocytes in vitro and in vivo. Short-term systemic administration of 5-FU caused both acute CNS damage and a syndrome of progressively worsening delayed damage to myelinated tracts of the CNS associated with altered transcriptional regulation in oligodendrocytes and extensive myelin pathology. Functional analysis also provided the first demonstration of delayed effects of chemotherapy on the latency of impulse conduction in the auditory system, offering the possibility of non-invasive analysis of myelin damage associated with cancer treatment.

CONCLUSIONS

Our studies demonstrate that systemic treatment with a single chemotherapeutic agent, 5-FU, is sufficient to cause a syndrome of delayed CNS damage and provide the first animal model of delayed damage to white-matter tracts of individuals treated with systemic chemotherapy. Unlike that caused by local irradiation, the degeneration caused by 5-FU treatment did not correlate with either chronic inflammation or extensive vascular damage and appears to represent a new class of delayed degenerative damage in the CNS.

Phase I trial of FLAGM with high doses of cytosine arabinoside for relapsed, refractory acute myeloid leukemia: study of the Japan Adult Leukemia Study Group (JALSG)

This study was designed to determine the optimal high dose for cytosine arabinoside (ara-C) in combination with fludarabine, granulocyte colony-stimulating factor, and mitoxantrone (FLAGM) in adult patients with relapsed or refractory acute myeloid leukemia. Nine patients were enrolled at increasing dosage levels of ara-C (8, 12, and 16 g/m2 per dose level). Ara-C and fludarabine were administered once a day at level 1, once or twice a day at level 2, and twice a day at level 3. All patients had grade 4 hematologic toxicity. The most common adverse events were of grade 2 or less, with nausea and vomiting being the most common (6 events), followed by diarrhea (5 events), and rash (5 events). Of the 13 grade 3 nonhematologic toxicities reported, the 2 most common were febrile neutropenia (6 events) and disseminated intravascular coagulation (3 events). No early deaths were observed. FLAGM with high-dose ara-C was considered safe for patients, and the recommended dosage of ara-C in this study was 2 g/m2 every 12 hours for a total dose of 16 g/m2.

Central nervous system toxicity from cancer therapies

The central nervous system (CNS) is an organ with a unique profile of vulnerability to antineoplastic treatments. In many cases, CNS neurotoxicity is the dose-limiting side effect of treatment for systemic and CNS neoplasms. Novel methods of delivering radiation and chemotherapy agents have led to recognition of new forms of CNS neurotoxicity. In this article, the authors review the most important CNS toxicities of cancer treatment.

Age and high-dose methotrexate are associated to clinical acute encephalopathy in FRALLE 93 trial for acute lymphoblastic leukemia in children

The objective of the study was to assess acute neurotoxicity associated with triple intrathecal therapy (TIT)+/-high-dose methotrexate (HD MTX) in children with acute lymphoblastic leukemia (ALL). 1395 children were enrolled on FRALLE 93 protocol from 1993 to 1999. Lower-risk group (LR, n=182) were randomized to weekly low-dose MTX at 25 mg/m(2)/week (LD MTX, n=81) or HD MTX at 1.5 g/m(2)/2 weeks x 6 (n=77). Intermediate-risk group (IR, n=672) were randomized to LD MTX (n=290) or HD MTX at 8 g/m(2)/2 weeks x 4 (n=316). Higher-risk group (HR, n=541) prednisone-responder patients received LD MTX and cranial radiotherapy. HR group steroid resistant cases were grafted (autologous or allogenic). TIT (MTX, cytarabine and methylprednisolone) was given every 2 weeks during 16-18 weeks and every 3 months during maintenance therapy in LR and IR patients. 52 patients (3.7%) developed neurotoxicity. Isolated seizures: n=15 (1.1%), peripheral and spinal neuropathy: n=17 (1.2%) and encephalopathy: n=20 (1.4%). Age >10 years was significantly associated with neurotoxicity (P=0.01) and use of HD MTX is associated with encephalopathy (P=0.03). Sequels are reported respectively in 60 and 33% of spinal neuropathy and encephalopathy cases. Current strategies tailoring risk of neurological sequels has to be defined.

Flushing out of cerebrospinal fluid as a therapy for acute cerebellar dysfunction caused by high dose of cytosine arabinoside: a case report

High dose of cytosine arabinoside is usually used in treatment of acute myelogenous leukemia. Here we report 1 case of a child who developed neurologic toxicity and rapidly improved after flushing out of cerebral spinal fluid, suggesting it could be treatment in the acute phase of toxicity. Efficacy of this treatment could be explained by reducing cytosine arabinoside metabolites in central nervous system.

Salvage Chemotherapy in Follicular Non-Hodgkin's Lymphoma: Focus on Tolerability

Follicular lymphoma (FL) is typically characterized by repeated remissions and relapses, and many patients receive a number of therapeutic interventions during their disease course. Although treatment options are evolving rapidly, stem cell transplantation offers a potentially favorable impact on survival. In general, many patients with FL are not eligible for this approach by virtue of age and/or comorbid disease. Salvage chemotherapy consequently remains the mainstay of treatment, being individualized according to disease and patient characteristics, goals of therapy, and patient preference. Many of the cytotoxic agents used in relapsed FL are highly myelotoxic, leading to significant morbidity and mortality, including febrile neutropenia, hemorrhage, and impaired quality of life. Nausea and vomiting can also be problematic, particularly with regimens incorporating carmustine, cisplatin, and high-dose cyclophosphamide. Other acute toxicities include mucositis, alopecia, extravasation injuries, and neurotoxicity. Late toxicities can also occur, sometimes months or even years after the administration of antineoplastic agents. Acute myeloid leukemias, myelodysplastic syndromes, or solid tumors can occur after chemotherapy with alkylating agents. The cardiotoxic profile of anthracycline antibiotics is well recognized, and several agents, including carmustine and cyclophosphamide, can cause lung injury. Persistent neurotoxicity, nephrotoxicity, ototoxicity, and vascular toxicity have also been reported in association with chemotherapeutic agents used in patients with relapsed FL. Novel therapeutic strategies might allow patients to achieve longer remissions, potentially reducing lifetime exposure to repeated cycles of chemotherapy and their attendant toxicities. These could include the use of more efficient preparative and purging approaches in the transplantation setting or the administration of rituximab maintenance therapy after (immuno) chemotherapy induction or transplantation.

Neurologic complications of cancer chemotherapy

Neurotoxicity related to cancer therapy is a common problem in oncology practice. Neurologic side effects can be dose-limiting, can inhibit treatment, and can substantially diminish quality of life. Symptoms may appear acutely after treatment, or remotely after therapy has been discontinued. Multiple therapies may share similar toxicities, and certain agents may potentiate symptoms. When faced with the development of neurologic complaints, familiarity with the most common complications is helpful in determining the etiology of these symptoms. This review will discuss the common complications of both established and novel agents used to treat cancer.

Drug-induced tremors

Tremor is a common complaint for many patients. Caffeine and beta-adrenergic agonists are well-recognised drugs that cause or exacerbate tremors. Other tremorogenic drugs, such as selective serotonin reuptake inhibitors and tricyclic antidepressants, are less well recognised. Recognition of the drugs that can cause or exacerbate tremors can help prompt diagnosis, avoids unnecessary tests, and allows clinicians to quickly take corrective action (usually by discontinuing the tremor-inducing drugs). The aim of this review is to provide clinicians with current information on drugs that are associated with tremor and the correct treatment of these drug-induced tremors.