Multifocal inflammatory leukoencephalopathy associated with levamisole and 5-fluorouracil: case report

Levamisole-Induced Leukoencephalopathy in Russia: Analysis of 30 Cases

AIMS

To raise medical specialists' awareness regarding the severity of possible complications of levamisole administration and demonstrate the role of accurate medical history collection in differential diagnosis.

BACKGROUND

Levamisole, an anthelmintic drug with immunomodulatory effects, has long been used worldwide till early 2000s, when its association with demyelinating leukoencephalopathy was established. However, in the developing countries it is still widely used for prevention and treatment of helminthic invasion in humans. Actual prevalence of levamisole-induced multiple inflammatory leukoencephalopathy (LEV-induced MIL) in Russia remains unknown, and therefore, the study of its frequency and characteristics is indisputably important.

OBJECTIVES

To determine the clinical features and MRI findings of levamisole-induced MIL in the Russian population and to analyse the frequency of diagnostic errors at the initial assessment.

METHODS

A single-center retrospective analysis of total 30 patients who were diagnosed with LEV-induced MIL and attended Research Center of Neurology was conducted. Inclusion criteria were 1) clinically: acute or subacute polysymptomatic onset of neurological disturbances, 2) MRI: multifocal demyelinating lesion with no evidence of dissemination in time, 3) anamnestic data: levamisole exposure from 2 to 8 weeks before symptoms onset as well as monophasic disease course (absence of relapses according to follow up assessments up to 3 years).

RESULTS

Clinically, presentation with constitutional symptoms, including headache, fever, fatigue and myalgia, focal motor disturbances and dysarthria prevailed in our cohort. On the brain MRI, multiple foci of demyelination with simultaneous gadolinium enhancement were observed. The link between neurological symptoms and levamisole intake has often been detected only during follow-up assessments. Patients were most often misdiagnosed with acute disseminated encephalomyelitis, stroke and multiple sclerosis. In most cases LEV-induced MIL was successfully treated with intravenous corticosteroids and/or plasma exchange (PLEX), however, residual neurologic symptoms preserved in some patients. Additionally, two detailed clinical cases of patients being initially misdiagnosed are presented in the article.

CONCLUSION

The differential diagnosis remains difficult for suspected cases of LEV-induced MIL that could lead to delayed therapy initiation, and consequently incomplete recovery. Growing evidence suggests that a single administration of levamisole even in low doses might potentially lead to severe neurological deficit or death. Therefore, changes in medication management policies are required in order to prevent uncontrolled use of levamisole.

Adverse reactions with levamisole vary according to its indications and misuse: a systematic pharmacovigilance study

AIM

Levamisole was initially prescribed for the treatment of intestinal worms. Because of immunomodulatory properties, levamisole has been used in inflammatory pathologies and in cancers in association with 5-fluorouracil. Levamisole is misused as a cocaine adulterant. Post-marketing reports have implicated levamisole in the occurrence of adverse drug reactions (ADRs) and its use is now limited in Europe and North America. In contrast, all other parts of the World continue to use single-dose as an anthelmintic. The aim of this study was to identify ADRs reported after levamisole exposure in VigiBase, the WHO's pharmacovigilance database, and analyze their frequency compared to other drugs and according to levamisole type of use.

METHODS

All levamisole-related ADRs were extracted from VigiBase®. Disproportionality analyses were conducted to investigate psychiatric, hepatobiliary, renal, vascular, nervous, blood, skin, cardiac, musculoskeletal and general ADRs associated with levamisole and other drugs exposure. In secondary analyses, we compared the frequency of ADRs between levamisole and mebendazole and between levamisole type of use.

RESULTS

Among the 1763 levamisole-related ADRs identified, psychiatric disorders (Reporting Odds-Ratio with 95% confidence intervals: 1.4 [1.2-2.6]), hepatobiliary disorders (2.4 [1.9-4.3]), vasculitis (6.5 [4.1-10.6]), encephalopathy (22.5 [17.4-39.9]), neuropathy (4.3 [2.9-7.1]), hematological disorders, mild rashes and musculoskeletal disorders were more frequently reported with levamisole than with other drug. The majority of levamisole-related ADRs occurred when the drug was administrated for a non-anti-infectious indication.

CONCLUSION

The great majority of the levamisole-related ADRs concerned its immunomodulatory indication and multiple doses regimen. Our results suggest that single-dose treatments for anthelmintic action have a good safety profile.

Targeting Thymidylate Synthase Enhances the Chemosensitivity of Triple-Negative Breast Cancer Towards 5-FU-Based Combinatorial Therapy

BACKGROUND

The ongoing treatment modalities for breast cancer (BC) primarily rely on the expression status of ER, PR and HER-2 receptors in BC tissues. Our strategy of chemosensitization provides new insights to counter chemoresistance, a major obstacle that limits the benefits of chemotherapy of mammary cancers.

METHODS

By utilizing a murine breast cancer model employing NSG mice bearing orthotopic triple-negative breast cancer (TNBC) xenografts, we have evaluated the ability of phytochemical curcumin in chemosensitizing BC to 5-Fluorouracil (5-FU) chemotherapy and the differential modulations of cellular events in response to this strategy, independent of their receptor status.

RESULTS

A significant synergistic antitumor potential was observed in the murine model with a sub-optimal dose treatment of 5-FU plus curcumin, as evaluated by a reduction in the tumor-related parameters. We authenticated the pivotal role of thymidylate synthase (TS) in regulating the 5-FU-curcumin synergism using the TNBC pre-clinical model. Our study also confirmed the pharmacological safety of this chemotherapeutic plus phytoactive combination using acute and chronic toxicity studies in Swiss albino mice. Subsequently, the molecular docking analysis of curcumin binding to TS demonstrated the affinity of curcumin towards the cofactor-binding site of TS, rather than the substrate-binding site, where 5-FU binds. Our concomitant in vivo and in silico evidence substantiates the superior therapeutic index of this combination.

CONCLUSION

This is the first-ever pre-clinical study portraying TS as the critical target of combinatorial therapy for mammary carcinomas and therefore we recommend its clinical validation, especially in TNBC patients, who currently have limited therapeutic options.

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.

Tetramisole and Levamisole Suppress Neuronal Activity Independently from Their Inhibitory Action on Tissue Non-specific Alkaline Phosphatase in Mouse Cortex

Tissue non-specific alkaline phosphatase (TNAP) may be involved in the synthesis of GABA and adenosine, which are the main inhibitory neurotransmitters in cortex. We explored this putative TNAP function through electrophysiological recording (local field potential ) in slices of mouse somatosensory cortex maintained in vitro. We used tetramisole, a well documented TNAP inhibitor, to block TNAP activity. We expected that inhibiting TNAP with tetramisole would lead to an increase of neuronal response amplitude, owing to a diminished availability of GABA and/or adenosine. Instead, we found that tetramisole reduced neuronal response amplitude in a dose-dependent manner. Tetramisole also decreased axonal conduction velocity. Levamisole had identical effects. Several control experiments demonstrated that these actions of tetramisole were independent from this compound acting on TNAP. In particular, tetramisole effects were not stereo-specific and they were not mimicked by another inhibitor of TNAP, MLS-0038949. The decrease of axonal conduction velocity and preliminary intracellular data suggest that tetramisole blocks voltage-dependent sodium channels. Our results imply that levamisole or tetramisole should not be used with the sole purpose of inhibiting TNAP in living excitable cells as it will also block all processes that are activity-dependent. Our data and a review of the literature indicate that tetramisole may have at least four different targets in the nervous system. We discuss these results with respect to the neurological side effects that were observed when levamisole and tetramisole were used for medical purposes, and that may recur nowadays due to the recent use of levamisole and tetramisole as cocaine adulterants.

Clinical features and magnetic resonance image analysis of 15 cases of demyelinating leukoencephalopathy induced by levamisole

The aim of this study was to explore the diagnostic value of magnetic resonance imaging (MRI) for levamisole-induced demyelinating leukoencephalopathy. The clinical features and MRI findings of 15 patients with levamisole-induced demyelinating leukoencephalopathy were retrospectively analyzed. The abnormality rate of the patients was demonstrated to be 100% by MRI, and scattered multiple cerebral foci were observed in all of the patients. The majority of the foci were located at the centrum ovale, peri-lateral cerebral ventricles and basal ganglia, while the remainder were located in the brain stem and cerebellum, as well as in the white matter regions of the temporal, frontal, apical and occipital lobes. In addition, mottling and ring-shaped enhancements were observed. The study demonstrated that MRI effectively displays demyelinating leukoencephalopathy, and that the combination of MRI with the medical history of the patient is of significance for the early diagnosis, differentiation and treatment of demyelinating leukoencephalopathy.

Clinical features and magnetic resonance image analysis of 15 cases of demyelinating leukoencephalopathy induced by levamisole

The aim of this study was to explore the diagnostic value of magnetic resonance imaging (MRI) for levamisole-induced demyelinating leukoencephalopathy. The clinical features and MRI findings of 15 patients with levamisole-induced demyelinating leukoencephalopathy were retrospectively analyzed. The abnormality rate of the patients was demonstrated to be 100% by MRI, and scattered multiple cerebral foci were observed in all of the patients. The majority of the foci were located at the centrum ovale, peri-lateral cerebral ventricles and basal ganglia, while the remainder were located in the brain stem and cerebellum, as well as in the white matter regions of the temporal, frontal, apical and occipital lobes. In addition, mottling and ring-shaped enhancements were observed. The study demonstrated that MRI effectively displays demyelinating leukoencephalopathy, and that the combination of MRI with the medical history of the patient is of significance for the early diagnosis, differentiation and treatment of demyelinating leukoencephalopathy.

[Late-onset leukoencephalopathy induced by long-term chemotherapy with capecitabine and cyclophosphamide for liver metastasis from breast cancer]

A 55-year-old woman with a 3-year and 4-month history of liver metastasis from breast cancer underwent chemotherapy with capecitabine and cyclophosphamide for following 10-months. She did not have hypertension and was not pregnant. She showed dysarthria and mild somnolence, and her conscious level developed to semicoma after 6 days. She had pyrexia. Cerebrospinal fluid (CSF) demonstrated increased cell-count and elevated protein but no evidence of positive cytological finding and cultivation of bacteria was found in the CSF. Brain magnetic resonance imaging (MRI) revealed multiple lesions with hyperintensity in the brain stem, bilateral middle cerebellar peduncles, left splenium of corpus callosum, bilateral basal ganglia, bilateral thalami, bilateral corona radiata, and bilateral subcortical white matters of parietal lobes on the T(2) weighted and fluid attenuated inversion recovery (FLAIR) images. These lesions demonstrated mild hyperintensity on the diffusion weighted images but did not demonstrate hypointensity on the T(1) weighted images. Capecitabine and cyclophosphamide were discontinued at 4th day after onset of symptoms, and her conscious disturbance showed improvement slowly since day 12 after cessation of these drugs and hyperintensity areas detected on FLAIR image of MRI showed decreasing intensity after three weeks of onset. Capecitabine is an oral prodrug converted to 5-fluorouracil (5-FU). 5-FU and cyclophosphamide are known to induce leukoencephalopathy. Reversible multiple lesions with leukoencephalopathy on brain MRI which is called as a posterior reversible encephalopathy syndrome (PRES). Capecitabine is also reported to induce PRES in rare cases. Combination of these drugs was considered for the possible cause to induce leukoencephalopathy like PRES. Usually leukoencephalopathy occurs in relatively early time after start of chemotherapy with capecitabine or cyclophosphamide, but we consider that late-onset leukoencephalopathy can be induced by long-term chemotherapy with these drugs. It is necessary to observe leukoencephalopathy by brain MRI regularly when these drugs are used.

Encephalopathy secondary to capecitabine chemotherapy: a case report and discussion

Introduction. Capecitabine is an oral prodrug of 5-fluorouracil (5-FU) chemotherapy and is licenced for the treatment of breast and gastrointestinal cancers. Multifocal inflammatory leukoencephalopathy has been associated with intravenous 5-FU, but only a few cases of capecitabine-induced encephalopathy have been reported.

Setting. We describe here a case of encephalopathy following administration of Epirubicin/ Cisplatin/Capecitabine chemotherapy, review those cases previously described and suggest recommendations for management.

Results. Symptoms of neurotoxicity from 5-FU and capecitabine usually include confusion, ataxia, nystagmus, dysarthria, sensory loss, and memory loss. Withdrawal of the drug generally leads to improvement of symptoms and steroids are of only questionable benefit.

Conclusion. Patients on fluouropyrimidine drugs with new neurological symptoms should be investigated with brain MRI scan and the drug should be withdrawn until symptoms resolve. Dihydropyrimidine dehydrogenase deficiency should be excluded and ideally an alternative chemotherapy regime sought. We would encourage reporting of such incidences to gain a clearer picture of the incidence and optimal management. J Oncol Pharm Practice (2009) 15: 237—239.

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.

5-fluorouracil-induced oligodendrocyte death and inhibitory effect of cycloheximide, Trolox, and Z-VAD-FMK in murine cortical culture

BACKGROUND

5-fluorouracil (5-FU) is a widely used anticancer drug. One of the adverse effects of this drug is selective cerebral white matter injury, but to the authors' knowledge its mechanism has not been well documented. The current study was performed to investigate the mechanism of cerebral white matter injury caused by 5-FU and to develop the intervention to attenuate its injury in vitro.

METHODS

Mixed oligodendrocyte/astrocyte cells were dissociated from specimens taken from approximately 2-day-old postnatal mouse cortex and cultured for 3-4 weeks. The culture cells were exposed to 5-FU, cycloheximide, emetine, Z-VAD-fmk, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)-quinoxaline (NBQX), Trolox, and epigallocatechin gallate. Oligodendrocyte cell death was assessed by counting the number of viable galactocerebroside-positive cells per x 100 field.

RESULTS

Mixed oligodendrocyte/astrocyte culture cells that were exposed to 5-FU (at doses of 10 microM, 30 microM, and 100 microM) for 24 hours ensued concentration-dependent oligodendrocyte death. The majority of oligodendrocytes, but few astrocytes, were injured by 100 microM 5-FU. Trolox, a vitamin E analog antioxidant, as well as cycloheximide (a protein synthesis inhibitor) and Z-VAD-fmk (a caspase inhibitor), significantly attenuated the 5-FU-induced oligodendrocyte death. However, NBQX, an alpha-amino-2,3-dihydro-5-methyl-3-oxo-4-isoxazolepropionic acid (AMPA) receptor antagonist, did not appear to effect the 5-FU-induced oligodendrocyte death.

CONCLUSIONS

The findings of the current study suggested that 5-FU led to oligodendrocyte death rather than astrocyte death by way of the apoptotic process, whereas antioxidants may prevent the 5-FU-induced oligodendrocyte cell death in vitro.

Fluorouracil-induced neurotoxicity

OBJECTIVE

To report a case of acute neurologic adverse effects related to fluorouracil administration and to review the neurotoxicity of this agent.

CASE SUMMARY

A 73-year-old white man with a history of esophageal carcinoma was treated with fluorouracil 1,500 mg iv daily for four days. After completing treatment, he presented with sudden onset of confusion, cognitive disturbances, a cerebellar syndrome, and repeated seizures. A magnetic resonance image of the brain showed no structural abnormalities, and cerebrospinal fluid examination was normal; none of the other laboratory tests provided an explanation for his symptoms. The patient was treated with anticonvulsants, and the cognitive changes resolved in 72 hours. The cerebellar signs, however, did not resolve completely and persisted when the patient was examined two weeks after discharge.

DISCUSSION

Fluorouracil can cause both acute and delayed neurotoxicity. Acute neurotoxicity manifests as encephalopathy or as cerebellar syndrome; seizures, as seen in our patient, have rarely been reported. Acute neurotoxicity due to fluorouracil is dose related and generally self-limiting. Various mechanisms for such toxicity have been postulated, and treatment with thiamine has been recommended. Delayed neurotoxicity has been reported when fluorouracil was given in combination with levamisole; this form of subacute multifocal leukoencephalopathy is immune mediated and responds to treatment with corticosteroids.

CONCLUSIONS

Clinicians should be aware of the adverse neurologic effects of fluorouracil and should include them in the differential diagnosis when patients receiving the drug present with neurologic problems.

5-Fluorouracil and levamisole exacerbate demyelination in susceptible mice infected with Theiler's virus

A multifocal inflammatory leukoencephalopathy is associated with the administration of 5-fluorouracil (5-FU), a pyrimidine analogue, and levamisole (LE), an immunomodulator, in patients receiving adjuvant therapy for colon cancer. Cerebral biopsy demonstrated features indistinguishable from multiple sclerosis. We tested whether administration of these agents directly resulted in inflammatory demyelination in mice or whether they exacerbated demyelination in a host predisposed to myelin injury. We used mice intracerebrally infected with Theiler's murine encephalomyelitis virus (TMEV) which serves as an excellent model for multiple sclerosis. Varying dosages of 5-FU (240 micrograms-2.4 mg) and LE (40 micrograms-1 mg) were administered alone or in combination on a fixed schedule to 52 normal SJL mice and 61 Theiler's virus-infected mice (51 SJL/J mice susceptible to demyelination; 10 C57BL10 mice resistant to demyelination). Controls included 6 noninfected SJL and 26 infected mice (16 susceptible; 10 resistant) treated with phosphate-buffered saline (PBS). Inflammation or demyelination was not detected in brains or spinal cords of noninfected SJL mice treated with 5-FU and/or LE. TMEV-susceptible SJL mice treated with LE alone or in combination with 5-FU demonstrated more extensive inflammation and demyelination at Day 45 than mice treated with PBS. Demyelination was accelerated in infected animals treated with these agents at 45 days but at 70 days a significant difference in extent of demyelination was no longer appreciated between treatment and control groups. Treatment with 5-FU and LE did not convert normally resistant TMEV-infected C57BL/10 mice to demyelination. These experiments support the hypothesis that 5-FU and LE may exacerbate inflammatory demyelination in a susceptible host.

Multifocal leukoencephalopathy associated with 5-fluorouracil and levamisole adjuvant therapy for colon cancer. A report of two cases and review of the literature. The INTACC. Intergruppo Nazionale Terpia Adiuvante Colon Carcinoma

BACKGROUND

Since 1990 the combination of 5-fluorouracil plus levamisole has been considered the standard therapy for stage B2-C resected colon cancer in the adjuvant setting. Since 1992, 14 cases of multifocal leukoencefalopathy following 5-fluorouracil and levamisole therapy have been reported.

PATIENTS AND METHODS

Two cases of this rare but severe neurological syndrome, observed at our Institution within the scope of the INTACC (Intergruppo Nazionale Terapia Adiuvante Colon Carcinoma, Italy) 01 study, are described.

CONCLUSIONS

The clinical and radiological features of the syndrome and the relationships between therapy (with the possible pivotal role played by levamisole) and onset of the multifocal leukoencephalopathy are analyzed in light of the literature data.

Cerebral demyelination syndrome in a patient treated with 5-fluorouracil and levamisole. The use of thallium SPECT imaging to assist in noninvasive diagnosis--a case report

BACKGROUND

The use of 5-fluorouracil (5-FU) and levamisole in patients with Stage III adenocarcinoma of the colon has now become standard. There have been several reports of a multifocal cerebral demyelination syndrome following 5-FU and levamisole administration.

METHODS

We describe a patient who developed focal neurologic symptoms while being treated with levamisole and 5-FU in whom the diagnosis of central nervous system (CNS) metastases was considered.

RESULTS

A magnetic resonance imaging (MRI) scan showed a diffuse, multifocal white matter process. Diagnostic evaluation did not support a diagnosis of CNS metastasis. 201Thallium chloride single photon emission computed tomography (SPECT) study was cold. A stereotactic brain biopsy disclosed demyelination but not tumor. The patient had complete functional resolution of symptoms with 1 month of dexamethasone therapy, although follow-up MRI scans have shown persistent abnormality on T2-weighted images.

CONCLUSIONS

In patients receiving 5-FU and levamisole who develop focal neurologic symptoms with an abnormal MRI scan, the diagnosis of CNS metastasis should not be made without a thorough diagnostic evaluation. We suggest the use of 201thallium chloride SPECT imaging to support the diagnosis of multifocal leukoencephalopathy related to 5-FU and levamisole. In atypical cases, a stereotactic brain biopsy may be required for confirmation.