Clinical trial of pyridoxine to reduce vincristine neurotoxicity

Chemotherapy-induced peripheral neuropathy in children and adolescent cancer patients

Brain cancer and leukemia are the most common cancers diagnosed in the pediatric population and are often treated with lifesaving chemotherapy. However, chemotherapy causes severe adverse effects and chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting and debilitating side effect. CIPN can greatly impair quality of life and increases morbidity of pediatric patients with cancer, with the accompanying symptoms frequently remaining underdiagnosed. Little is known about the incidence of CIPN, its impact on the pediatric population, and the underlying pathophysiological mechanisms, as most existing information stems from studies in animal models or adult cancer patients. Herein, we aim to provide an understanding of CIPN in the pediatric population and focus on the 6 main substance groups that frequently cause CIPN, namely the vinca alkaloids (vincristine), platinum-based antineoplastics (cisplatin, carboplatin and oxaliplatin), taxanes (paclitaxel and docetaxel), epothilones (ixabepilone), proteasome inhibitors (bortezomib) and immunomodulatory drugs (thalidomide). We discuss the clinical manifestations, assessments and diagnostic tools, as well as risk factors, pathophysiological processes and current pharmacological and non-pharmacological approaches for the prevention and treatment of CIPN.

A Systematic Review of the Benefit of B-Vitamins as a Complementary Treatment in Cancer Patients

B-vitamins act as enzymatic co-factors in immune functions, therefore they are considered to reduce chemotherapy-induced side effects in cancer patients. We conducted a systematic search, screening five electronic databases (Embase, Cochrane, PsychInfo, CINAHL and Medline) to find studies on the effectiveness and potential harm of B-vitamin therapy on cancer patients. Out of the 7465 search results, 11 RCTs about vitamin B6, B12 and B-vitamins in combination were included in this systematic review. A total of 1546 patients with diverse types of cancer were evaluated. Overall, most studies were of acceptable quality and reported consistent results. Studies examining the effectiveness of vitamin B6 reported that there is no significant impact on decreasing the incidence and severity of chemotherapy-induced side effects (e.g., hand-foot syndrome), the necessity of chemotherapy dose-modifications or improving patients' quality of life, tumor response/progression, and overall survival. Two studies reported that vitamin B12 could be effective in the alleviation of symptoms resulting from chemotherapy; it might decrease motor, sensory and pain symptoms of peripheral neuropathy. However, a combination of B vitamins may not reduce the incidence of chemotherapy-induced peripheral neuropathy. All in all, the evidence on B-vitamins in cancer patients is low and supplementation cannot be recommended.

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.

Pediatric Oncology Patients With Vincristine-Induced Recurrent Laryngeal Nerve Palsy: Two Case Reports and a Brief Review of Literature

INTRODUCTION

Vincristine (VCR) is a chemotherapeutic agent used widely in the treatment of hematologic and solid tumors, known to result in neurotoxicity, especially with cumulative administrations. Bilateral vocal fold palsy (VFP) is a rare but life-threatening complication of VCR. We report 2 patients with hepatoblastoma presenting with stridor following VCR treatment and propose a management plan.

METHODS

Electronic medical records of oncology patients treated at a tertiary hospital with VCR-induced VFP were reviewed. Literature review was performed in PubMed using the terms: hoarseness, VFP, stridor, vincristine.

RESULTS

A total of 23 children with VCR-induced VFP were identified from the literature review and adding on our 2 cases. Seventeen (77.3%) were male and 5 (22.7%) were female. The median presenting age was 36.0 months (5-204 months). Acute lymphoblastic leukemia, 15 of 23 (65.2%), was the most common malignancy. Eighteen patients (78.3%) had bilateral VFP and 5 (21.7%) had unilateral VFP. The mean time to VF function recovery was 167.3 days (median: 200.5 days, range: 7-270 days) in the intervention group versus 72.1 days (median: 31.5 days, range: 3-240 days) in the conservative group. One patient in the intervention group had persistent VFP. Sixteen patients (69.6%) were observed, 4 (17.4%) underwent tracheostomy, 1 (4.35%) was intubated, 1 (4.35%) underwent cordectomy, and 1 (4.35%) required positive pressure support. Vincristine was restarted in 12 patients (54.5%), of which 4 developed recurrence of airway symptoms and had to stop VCR.

CONCLUSION

A new-onset hoarseness or stridor in a child on VCR should raise the suspicions of VFP. The assumption of an upper respiratory-induced hoarseness or stridor should be avoided. Decisions regarding readministration of VCR and possible airway interventions should be made via a multidisciplinary team approach.

Oesophageal narrowing during combination chemotherapy in Ewing's sarcoma: Is vincristine a culprit?

Vincristine is a widely used chemotherapeutic agent in paediatric oncology. A 7-year-old boy was diagnosed with non-metastatic Ewing's sarcoma of the pelvis. He was started on chemotherapy with vincristine-cyclophosphamide-adriamycin alternate with ifosfamide-etoposide. He developed recurrent vomiting after three cycles of chemotherapy. Evaluation showed oesophageal stricture involving the middle and lower third part. Biopsy was non-conclusive. His symptoms improved with dilatation. A chemotherapy-induced neuropathic dysmotility was suspected, and his chemotherapy was continued with serial dilatation. Vincristine, being neurotoxic, was suspected to be the reason of this morbidity. His need of dilatation decreased, and symptoms improved remarkably after completion of chemotherapy.Vincristine-induced oesophageal dysmotility is a rare side effect. There is no consensus on management. Omission of this effective agent in such situation is debatable.

Vincristine-Induced Neuropathy Presenting as Ptosis and Ophthalmoplegia in a 2-Year-Old Boy

Vincristine is used in the treatment of leukemias, solid tumors, and lymphomas. A case of a 2-year-old boy undergoing treatment for leukemia who developed sudden onset bilateral ptosis and ophthalmoplegia along with generalized neuropathy due to vincristine's neurotoxic effects is presented. He was successfully treated with pyridoxine and pyridostigmine. The possible mechanisms of action and the treatment for vincristine-induced neuropathy are discussed. Prompt treatment and close follow-up is needed, especially in children because prolonged ptosis and motility restriction may have a profound effect on a child's visual function.

Ptosis during hematologic malignancy in children

Neurological symptoms such as ptosis may develop due to either chemotherapeutic agents or involvement of the central nervous system (CNS) during hematologic malignancy. It is difficult to make this distinction according to clinical symptoms and magnetic resonance imaging findings. If the neurologic symptoms are increased, it is a warning of CNS involvement. Herein are described the clinical and neuroimaging features of three patients with hematologic malignancy who presented with ptosis.

Successful treatment of vincristine induced ptosis and polyneuropathy with pyridoxine and pyridostigmine in a child with acute lymphoblastic leukemia

Vincristine is used in the treatment of solid tumors, lymphoma and leukemia in children. The dose-limiting toxicity is its neurotoxicity. We describe a 2-year-old girl with acute lymphoblastic leukemia who developed vincristine-induced polyneuropathy with bilateral ptosis and recovered on treatment with pyridoxine and pyridostigmine.

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.

Vincristine-induced unilateral ptosis in a child

Vincristine is a vinca alkaloid used in combination with other agents in the treatment of solid tumors, lymphoma, and leukemia, as well as for idiopathic thrombocytopenic purpura and autoimmune hemolytic anemia. A dose-limiting complication of vinca alkaloids is neurotoxicity. Vincristine is the oldest and also the most neurotoxic agent in this group. Described here is the case of a 4-year-old girl with unilateral palpebral ptosis. She has been diagnosed with precursor B-cell acute lymphoblastic leukemia. Ptosis was noted on the 45th day of therapy, and the last vincristine was administered on the 28th day of protocol 1. Vincristine-induced unilateral palpebral ptosis is a novel finding. Experience with this case suggests conservative treatment, with periodic examination, especially if ptosis is mild.

Pyridoxine and pyridostigmine treatment in vincristine-induced neuropathy

Vincristine is a commonly used antineoplastic drug and frequently causes neurotoxicity. Here the authors report a 4-year-old boy with acute lymphoblastic leukemia in whom vincristine-induced peripheral and cranial neuropathy developed during remission induction therapy. The patient seemed to benefit from pyridoxine and pyridostigmine therapy greatly and this therapy is recommended in patients with severe vincristine-induced neuropathy.

Inadvertent intrathecal vincristine administration: a neurosurgical emergency. Case report

Vincristine has a high neurotoxicity level. If given intrathecally by accident, it can cause ascending radiculomyeloencephalopathy, which is almost always fatal. The authors report a rare case in which vincristine was accidentally injected intrathecally into a 32-year-old man. The patient, who had Burkitt lymphoma, was neurologically intact, and it is likely that his survival was made possible due to aggressive neurosurgical therapy. After immediate cerebrospinal fluid (CSF) aspiration, external ventricular and lumbar drains were placed for CSF irrigation, which was continued for 6 days. This CSF irrigation was combined with 1) the intrathecal administration of fresh-frozen plasma to bind the vincristine and 2) an intravenous antineurotoxic therapy involving pyridoxine, folic acid, and glutamic acid. The patient's first sensorimotor deficits occurred after 2 days, led to an incomplete sensorimotor dysfunction below T-9 within the next 17 days, but progressed no further. Supported by the scarce data culled from the reviewed literature, the authors hypothesize that prolonged CSF irrigation combined with antineurotoxic therapy contributed to the patient's satisfactory outcome. In conclusion, accidental intrathecal vincristine injection requires emergency and adequate neurosurgical therapy.

Vincristine induced cranial polyneuropathy

We describe a 5-year-old girl showed recovery of vincristine induced cranial polyneuropathy with pyridoxine and pyridostigmine treatment. A 5-year-old girl was diagnosed preB cell Acute Lymphoblastic Leukemia (ALL). She received chemotherapy according to the previously described modified St. Jude total therapy studies XIII. Five days after the fourth dose of vincristine, she presented with bilateral ptosis. Neurological examination revealed bilateral ptosis, and complete external opthalmoplegia with normal pupillary and corneal reflexes. She received 3.8 mg cumulative dose of vincristin before development of ptosis. A neuroprotective and neuroregenerative treatment attempt with pyridoxine and pyridostigmine was initiated. The bilateral ptosis markedly improved after 7 days of pyridoxine and pyridostigmine treatment and completely resolved after two weeks. The both agents were given for 3 weeks and were well tolerated without any side effects. During the follow up period we did not observe residue or recurrence of the ptosis.

Antineoplastic therapy-induced palmar plantar erythrodysesthesia ('hand-foot') syndrome. Incidence, recognition and management

Palmar plantar erythrodysesthesia (PPE) is a distinctive and relatively frequent toxic reaction related to some chemotherapeutic agents. Doxorubicin, cytarabine, docetaxel, and fluorouracil are the most frequently implicated agents. PPE seems to be dose dependent and both peak drug concentration and total cumulative dose determine its occurrence. PPE presents as a painful erythema, often preceded by paresthesia, located on the palms and soles in the context of treatment with chemotherapy. Histologically, PPE shows few specific findings. Mild spongiosis, scattered necrotic and dyskeratotic keratinocytes and vacuolar degeneration of the basal layer is seen. Dermal changes in most cases include dilated blood vessels, papillary edema, and a sparse superficial perivascular lymphohistiocytic infiltrate can be found in varying degrees in the epidermis. Withdrawal or dose reduction of the implicated drug usually gives rise to amelioration of the symptoms. Supportive treatments such as topical wound care, elevation, and cold compresses may help to relieve the pain. Use of systemic corticosteroids, pyridoxine (vitamin B6), blood flow reduction, and, recently, topical 99% dimethyl-sulfoxide have been used with variable outcomes. It could be of interest to consider them as preventive measures when drugs with a strong association with PPE are going to be administered.

Neurologic Complications of Cancer Therapy

Although progress in cancer research is paralleled by the discovery and development of novel chemotherapeutic agents, the benefits of these agents are offset by their side-effect profiles. Of the numerous adverse effects associated with antineoplastic drugs, peripheral neuropathy is the most frequent and is often debilitating. This article reviews the treatment options--both primary and secondary--for neuropathic complications of cancer therapy. Before a potentially neurotoxic chemotherapeutic regimen is started, patients should undergo 1) a baseline neurologic history for possible coexisting risk factors for neuropathy; 2) physical evaluation; and 3) if indicated, electrophysiologic testing, including nerve conduction studies and electromyography. Patients should be followed closely for the development of neuropathic signs and symptoms. When symptoms (eg, paresthesias or pain) or deficits (eg, weakness) develop, their severity and their effect on quality of life will determine whether the neurotoxic chemotherapy should be continued at a lower dose or discontinued. Neuropathic pain should be treated aggressively with a stepwise approach. The decision to initiate therapy should be guided first by the severity of pain and second by the convenience of dosing and the side-effect profile of the medication. Specific antineuropathic pain therapy may begin with a tricyclic antidepressant (TCA), titrated to 100 to 150 mg/d, unless anticholinergic side effects appear before this dosage is reached. The TCA may be replaced by or supplemented with antiepileptic agents, such as gabapentin, which is attractive because of its rapid dose titration (maximum, 3600 mg/d) and minimal interaction with other medications. In addition to pharmacologic therapies targeting symptom management, new therapies directed at preventing the onset or progression of neurotoxicity are desperately needed.

Effects of the ACTH(4-9) analogue, ORG 2766, on vincristine cytotoxicity in two human lymphoma cell lines, U937 and U715

The use of cytotoxic drug vincristine (VCR) is limited by the occurrence of peripheral neuropathy. A neurotrophic ACTH(4-9) analogue, ORG 2766, is being studied for its protective effect. Possible modulatory effects of ORG 2766 on tumour cell growth and interference with the cytotoxic efficacy of VCR were studied in two human lymphoma cell lines, U937 and U715. The effects of ORG 2766 on cell growth and survival and on VCR-mediated cytotoxicity were investigated using two MTT-based assays to study direct cytotoxic effects and to assess residual growth after pretreatment. Treatment with ORG 2766 alone had no effect on cell growth and survival. Neither did this drug affect VCR cytotoxicity. However, after 96 h pretreatment with ORG 2766 and a culture period of 7 days, a reduction in residual growth and a potentiation of VCR-induced inhibition of growth capacity was observed in U715 cells, and to some extent also in U937 cells. It is concluded that ORG 2766 has no stimulatory effects on tumour growth and does not negatively interfere with VCR-mediated cytotoxicity. Rather it enhances the cytostatic effect of VCR. It is suggested that ORG 2766 can safely be used in clinical trials investigating the ability of ORG 2766 to counteract VCR-induced neurotoxicity.

Neurotoxicity of antineoplastic agents

PURPOSE

to review the neurotoxicity associated with antineoplastic agents.

METHODS

four hundred articles, abstracts and book chapters were selected for review. One hundred and ninety (articles, book chapters and abstracts) were identified as representative of the important aspects of neurotoxicity to be presented in this review.

RESULTS

in general the dose, schedule and route of administration significantly determine the incidence and outcome of antineoplastic agents neurotoxicity. An updated and detailed review of neurotoxicity is provided with special attention to vinca alkaloids, cisplatin and biologic response modifiers. The neurotoxic side effects of some of the new approaches in cancer therapy and some of the investigational agents are discussed. Guidelines for the prevention and management of this toxicity are presented. In addition, suggestions are made in regard to the preclinical and clinical screening of new agents for neurotoxicity.

CONCLUSION

quality of life issues have become a focal point in many clinical trials. Neurotoxicity associated with antineoplastic therapy clearly has an impact on the short and long term quality of the life of cancer patients. A better understanding of this toxicity requires developing reliable and predictive models to screen new agents prior to their introduction into clinical trials; a more detailed and uniform grading system; and the prospective evaluation of neurotoxicity in clinical trials of new antineoplastic agents.

The clinical pharmacology and use of antimicrotubule agents in cancer chemotherapeutics

Although there has been a rapid expansion of the number of classes of compounds with antineoplastic activity, few have played a more vital role in the curative and palliative treatment of cancers than the antimicrotubule agents. Although the vinca alkaloids have been the only subclass of antimicrotubule agents that have had broad experimental and clinical applications in oncologic therapeutics over the last several decades, the taxanes, led by the prototypic agent taxol, are emerging as another very active class of antimicrotubule agents. After briefly reviewing the mechanisms of antineoplastic action and resistance, this article comprehensively reviews the clinical pharmacology, therapeutic applications, and clinical toxicities of selected antimicrotubule agents.

Evolution of neuropathy and myopathy during intensive vincristine/corticosteroid chemotherapy for non-Hodgkin's lymphoma

Neuropathy and myopathy are common sequelae of intensive chemotherapy protocols that contain vincristine and corticosteroids. The authors prospectively monitored the evolution of neuropathy and myopathy during an intensive 12-week chemotherapy program for patients with intermediate and high-grade non-Hodgkin's lymphoma. In this study, vincristine was administered by bolus injection followed by a 3-day continuous intravenous (IV) infusion (total dose of 2.0 mg/m2 every other week); the maximum dose of vincristine was not arbitrarily limited. Cronassial, a mixture of four naturally occurring gangliosides, was administered in a randomized double-blind test to evaluate whether this agent could prevent vincristine-induced neuropathy. High doses of dexamethasone (50 mg/d for 3 days weekly or every other week) were also prescribed. Patients were monitored every 4 weeks with comprehensive physical and neurologic examinations and electrophysiologic studies of peripheral nerve function. Twenty-seven patients were fully evaluable. Weakness was a prominent adverse reaction in this study, and all patients had moderate to severe signs and symptoms of neuropathy and myopathy. Cronassial (100 mg) administered by intramuscular (IM) injection daily provided no protection against the development of neuropathic symptoms. Vincristine typically impaired fine-motor coordination initially, whereas corticosteroids were associated with delayed development of proximal muscle weakness. Results of electrodiagnostic studies did not add to the clinical examination results. The authors conclude that symptomatic weakness due to neuropathy or myopathy appears in a predictable manner during intensive vincristine/corticosteroid-based treatment protocols. Simple clinical tests can be used to rapidly distinguish between toxic effects due either to vincristine or corticosteroids, and routine implementation of these tests can prevent inappropriate dose attenuation of these agents.

Abnormal vitamin B6 status in childhood leukemia

Vitamin B6 is involved in many biological processes of potential relevance to carcinogenesis and tumor growth, including DNA synthesis and maintenance of immunocompetence, yet very little information exists on B6 nutritional status in childhood leukemia. Using a radioenzymatic assay, the authors measured plasma pyridoxal 5'-phosphate (PLP), the biologically active form of B6, in 11 newly diagnosed untreated children with leukemia and 11 age-matched controls. The children with leukemia had significantly lower PLP levels than the controls. In 26 additional leukemia patients and 26 additional controls, a high-performance liquid chromatography assay also demonstrated lower plasma PLP levels in childhood leukemia compared with controls. These differences were significant for both acute lymphoblastic leukemia (ALL) and for acute nonlymphoblastic leukemia (ANLL). The PLP values did not correlate with indices of leukemia cell burden, but did correlate with reported B6 intake, suggesting that illness-related diet changes are at least partially responsible for the low PLP levels. Before any chemotherapy, overall nutritional status was suboptimal in 53% of ALL cases and 57% of ANLL cases. Newly diagnosed children with leukemia have suboptimal overall nutrition as well as suboptimal vitamin B6 status.

Clinical pharmacology of cancer chemotherapy in children

The pharmacokinetics of most anticancer drugs are highly variable in children, and are commonly different when children are compared to adults. Several recent studies have demonstrated that variability in systemic exposure due to interpatient pharmacokinetic variability, may be related to the probability of oncolytic effects or toxicity for some anticancer drugs. This review has exemplified differences in the clinical pharmacology of several anticancer drugs, when children are compared to adults. Such age-related differences in the pharmacokinetics and pharmacodynamics of these drugs, together with biologic differences between pediatric and adult cancers, provide the rationale for systematically conducting pediatric phase I through IV studies of anticancer drugs and denote the risks of relying on adult trials to identify new therapeutic strategies for childhood cancers.

Amelioration of vincristine neurotoxicity by glutamic acid

Neurotoxicity is the principal limiting side effect of the widely used antitumor agent, vincristine. Following evaluation of glutamic acid as a potential modifier of vincristine toxicity in preclinical studies in mice and a preliminary clinical trial, a prospective, double-blind, placebo-controlled, randomized trial was conducted by the Piedmont Oncology Association. Of 87 patients entered into the study, 84 were evaluable, including 42 patients who were randomly assigned to receive vincristine 1.0 mg/m2 weekly for six doses and 42 patients who were assigned to receive glutamic acid 500 mg orally three times daily plus vincristine. The following neurotoxic signs and symptoms were evaluated before each dose of vincristine: reflex changes, paresthesias, constipation, strength, and mental changes. Loss of the Achilles tendon reflex, an objective parameter, was noted in 19 percent of patients receiving glutamic acid and 42 percent of control subjects (p = 0.03). Development of moderate to severe paresthesias, a subjective parameter, occurred in 19 percent of the glutamic acid group and 36 percent of the placebo group (p = 0.09). Overall moderate neurotoxicity (6 units or more), determined by adding the grade of each neurotoxic parameter for the weekly clinic visit in which maximum neurotoxicity occurred, was observed in 21 percent of patients receiving glutamic acid and 43 percent of those in the control group (p = 0.04). Hematologic and gastrointestinal side effects occurred with similar frequency in the two groups. The administration of glutamic acid has decreased vincristine-induced neurotoxicity without any attendant side effects.

Clinical trial of folinic acid to reduce vincristine neurotoxicity

In a murine model system, folinic acid demonstrated host-protective properties during administration of repetitive and lethal doses of vincristine (VCR). Subsequently, folinic acid was evaluated in patients receiving VCR during an adjuvant chemotherapy program for stage II carcinoma of the breast. The toxicities, cumulative VCR dosage, and percentage of ideal dosage observed in 18 patients receiving folinic acid have been compared with those observed in 70 patients who previously received VCR without folinic acid in the same chemotherapy program. All patients ideally were intended to receive VCR 1.0 mg/m2 weekly for 6 weeks, with dose modification for neurotoxicity. Treatment patients received folinic acid 800 mg PO daily in three divided doses during the 6-week course. The degree of neurotoxic manifestations of VCR was similar in the treatment and comparison patients. Absent to mild neurotoxicity was observed in approximately 70% of patients in both groups; moderate or greater neurotoxicity occurred in about 30% of patients in both groups. Full dosage (6.0 mg/m2) was attained in 7 (39%) treatment patients and 17 (24%) comparison patients (P = 0.21). The mean percentage of the ideal dosage of VCR was 73.7 +/- 28.7 in patients receiving folinic acid and 76.1 +/- 20.5 in those given only VCR (P = 0.69). Hematologic toxicities were similar in both groups, but nausea occurred more frequently in the folinic acid group. Folinic acid in this dose and schedule afforded no protection from the neurotoxic side effects of VCR.