Glutamine as a Neuroprotective Agent in High-dose Paclitaxel-induced Peripheral Neuropathy: A Clinical and Electrophysiologic Study

Pre-treatment amino acids and risk of paclitaxel-induced peripheral neuropathy in SWOG S0221

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a treatment-limiting and debilitating neurotoxicity of many commonly used anti-cancer agents, including paclitaxel. The objective of this study was to confirm the previously found inverse association between pre-treatment blood concentrations of histidine and CIPN occurrence and examine relationships of other amino acids with CIPN severity.

METHODS

Pre-treatment serum concentrations of 20 amino acids were measured in the SWOG S0221 (NCT00070564) trial of patients with early-stage breast cancer receiving paclitaxel. The associations between amino acids and CIPN severity were tested in regression analysis adjusted for paclitaxel schedule, age, self-reported race, and body mass index with Bonferroni correction. The network of metabolic pathways of amino acids was analyzed using over-representation analysis. The partial correlation network of amino acids was evaluated using a debiased sparse partial correlation algorithm.

RESULTS

In the primary analysis, histidine concentration was not associated with CIPN occurrence (odds ratio (OR) = 0.97 [0.83, 1.13], p = 0.72). In secondary analyses, higher concentrations of four amino acids, glutamate (β = 0.58 [0.23, 0.93], p = 0.001), phenylalanine (β = 0.54 [0.19, 0.89], p = 0.002), tyrosine (β = 0.57 [0.23, 0.91], p = 0.001), and valine (β = 0.58 [0.24, 0.92], p = 0.001) were associated with more severe CIPN, but none of these associations retained significance after adjustment. In the over-representation analysis, no amino acid metabolic pathways were significantly enriched (all FDR > 0.05). In the network of enriched pathways, glutamate metabolism had the highest centrality.

CONCLUSIONS

This analysis showed that pre-treatment serum amino acid concentrations are not strongly predictive of CIPN severity. Prospectively designed studies that assess non-amino acid metabolomics predictors are encouraged.

Pre-treatment Amino Acids and Risk of Paclitaxel-induced Peripheral Neuropathy in SWOG S0221

Background

Chemotherapy-induced peripheral neuropathy (CIPN) is a treatment-limiting and debilitating neurotoxicity of many commonly used anti-cancer agents, including paclitaxel. The objective of this study was to confirm the previously found inverse association between pre-treatment blood concentrations of histidine and CIPN occurrence and examine relationships of other amino acids with CIPN severity.

Methods

Pre-treatment levels of 20 amino acid concentrations were measured via a targeted mass spectrometry assay in banked serum from the SWOG S0221 (NCT00070564) trial of patients with early-stage breast cancer receiving paclitaxel. The associations between amino acid levels and CIPN occurrence or severity were tested in regression analysis adjusted for paclitaxel schedule, age, self-reported race, and body mass index with Bonferroni correction for multiple comparisons. The network of metabolic pathways of amino acids was analyzed using over-representation analysis in MetaboAnalyst. The partial correlation network of amino acids was evaluated using a debiased sparse partial correlation algorithm and Cytoscape.

Results

In the primary analysis, histidine concentration was not associated with CIPN occurrence (odds ratio (OR) = 0.97 [0.83, 1.13], p = 0.72). In a secondary analysis, no amino acid was associated with CIPN occurrence (all p > 0.0025). Higher concentrations of four amino acids, glutamate (β = 0.58 [0.23, 0.93], p = 0.001), phenylalanine (β = 0.54 [0.19, 0.89], p = 0.002), tyrosine (β = 0.57 [0.23, 0.91], p = 0.001), and valine (β = 0.58 [0.24, 0.92], p = 0.001) were associated with more severe CIPN, but none of these associations retained significance after adjustment. In the over-representation analysis, no amino acid metabolic pathways were significantly enriched (all FDR > 0.05). In the network of enriched pathways, glutamate metabolism had the highest centrality.

Conclusions

This analysis showed that pre-treatment serum amino acid concentrations are not strongly predictive of CIPN severity. Future prospectively designed studies that assess non-amino acid metabolomics predictors are encouraged.

Fluocinolone Acetonide Enhances Anterograde Mitochondria Trafficking and Promotes Neuroprotection against Paclitaxel-Induced Peripheral Neuropathy

Paclitaxel (PTX)-induced peripheral neuropathy (PIPN) is a debilitating health condition which is a result of degeneration of peripheral nerves found in extremities. Currently, there are no established treatment methods that can prevent or protect from PIPN. Fluocinolone acetonide (FA) has been recently identified as a potential candidate for protection from PIPN. However, the fundamental mechanism of action is still unknown. In this study, we showed that enhanced anterograde mitochondrial movement in dorsal root ganglion (DRG) cells has a major role in FA-mediated neuroprotection in PIPN. In this study, cells were treated with PTX or FA along with their combination followed by mitochondrial fluorescence staining. Somal (proximal) and axonal (distal) mitochondria were selectively stained using a microfluidic compartmentalized chamber with different MitoTrackers blue and red, respectively, which we termed, the two-color staining approach. Results revealed that axons were protected from degeneration by the PTX effect when treated along with FA. PTX exposure alone resulted in low mitochondrial mobility in DRG cells. However, cotreatment with PTX and FA showed significant enhancement of anterograde trafficking of somal (proximal) mitochondria to distal axons. Similarly, cotreatment with FA restored mitochondrial mobility significantly. Overall, this study affirms that increasing mitochondrial recruitment into the axon by cotreatment with FA can be a worthwhile strategy to protect or prevent PIPN. The proposed two-color staining approach can be extended to study trafficking for other neuron-specific subcellular organelles.

Combination L-Glutamine with Gemcitabine and Nab-Paclitaxel in Treatment-Naïve Advanced Pancreatic Cancer: The Phase I GlutaPanc Study Protocol

Advanced pancreatic cancer is underscored by progressive therapeutic resistance and a dismal 5-year survival rate of 3%. Preclinical data demonstrated glutamine supplementation, not deprivation, elicited antitumor effects against pancreatic ductal adenocarcinoma (PDAC) alone and in combination with gemcitabine in a dose-dependent manner. The GlutaPanc phase I trial is a single-arm, open-label clinical trial investigating the safety of combination L-glutamine, gemcitabine, and nab-paclitaxel in subjects (n = 16) with untreated, locally advanced unresectable or metastatic pancreatic cancer. Following a 7-day lead-in phase with L-glutamine, the dose-finding phase via Bayesian design begins with treatment cycles lasting 28 days until disease progression, intolerance, or withdrawal. The primary objective is to establish the recommended phase II dose (RP2D) of combination L-glutamine, gemcitabine, and nab-paclitaxel. Secondary objectives include safety of the combination across all dose levels and preliminary evidence of antitumor activity. Exploratory objectives include evaluating changes in plasma metabolites across multiple time points and changes in the stool microbiome pre and post L-glutamine supplementation. If this phase I clinical trial demonstrates the feasibility of L-glutamine in combination with nab-paclitaxel and gemcitabine, we would advance the development of this combination as a first-line systemic option in subjects with metastatic pancreatic cancer, a high-risk subgroup desperately in need of additional therapies.

Emerging Approaches for the Management of Chemotherapy-Induced Peripheral Neuropathy (CIPN): Therapeutic Potential of the C5a/C5aR Axis

Chemotherapy-induced peripheral neuropathy (CIPN) is the most common neurologic complication of chemotherapy, resulting in symptoms like pain, sensory loss, and numbness in the hands and feet that cause lots of uneasiness in patients with cancer. They often suffer from pain so severe that it interrupts the treatment, thus invalidating the entire chemotherapy-based healing process, and significantly reducing their quality of life. In this paper, we underline the role of the complement system in CIPN, highlighting the relevance of the C5a fragment and its receptor C5aR1, whose activation is thought to be involved in triggering a cascade of events that can lead to CIPN onset. Recent experimental data showed the ability of docetaxel and paclitaxel to specifically bind and activate C5aR1, thus shining light on one of the molecular mechanisms by which taxanes may activate a cascade of events leading to neuropathy. According to these new evidence, it was possible to suggest new mechanisms underlying the pathophysiology of CIPN. Hence, the C5a/C5aR1 axis may represent a new target for CIPN treatment, and the use of C5aR1 inhibitors can be proposed as a potential new therapeutic option to manage this high unmet medical need.

Endoplasmic Reticulum Stress in Chemotherapy-Induced Peripheral Neuropathy: Emerging Role of Phytochemicals

Chemotherapy-induced peripheral neuropathy (CIPN) is a significant dose-limiting long-term sequela in cancer patients undergoing treatment, often leading to discontinuation of treatment. No established therapy exists to prevent and/or ameliorate CIPN. Reactive oxygen species (ROS) and mitochondrial dysregulation have been proposed to underlie the pathobiology of CIPN. However, interventions to prevent and treat CIPN are largely ineffective. Additional factors and mechanism-based targets need to be identified to develop novel strategies to target CIPN. The role of oxidative stress appears to be central, but the contribution of endoplasmic reticulum (ER) stress remains under-examined in the pathobiology of CIPN. This review describes the significance of ER stress and its contribution to CIPN, the protective role of herbal agents in countering ER stress in nervous system-associated disorders, and their possible repurposing for preventing CIPN.

Chemotherapy-Induced Peripheral Neuropathy: Epidemiology, Pathomechanisms and Treatment

PURPOSE

This review provides an update on the current clinical, epidemiological and pathophysiological evidence alongside the diagnostic, prevention and treatment approach to chemotherapy-induced peripheral neuropathy (CIPN).

FINDINGS

The incidence of cancer and long-term survival after treatment is increasing. CIPN affects sensory, motor and autonomic nerves and is one of the most common adverse events caused by chemotherapeutic agents, which in severe cases leads to dose reduction or treatment cessation, with increased mortality. The primary classes of chemotherapeutic agents associated with CIPN are platinum-based drugs, taxanes, vinca alkaloids, bortezomib and thalidomide. Platinum agents are the most neurotoxic, with oxaliplatin causing the highest prevalence of CIPN. CIPN can progress from acute to chronic, may deteriorate even after treatment cessation (a phenomenon known as coasting) or only partially attenuate. Different chemotherapeutic agents share both similarities and key differences in pathophysiology and clinical presentation. The diagnosis of CIPN relies heavily on identifying symptoms, with limited objective diagnostic approaches targeting the class of affected nerve fibres. Studies have consistently failed to identify at-risk cohorts, and there are no proven strategies or interventions to prevent or limit the development of CIPN. Furthermore, multiple treatments developed to relieve symptoms and to modify the underlying disease in CIPN have failed.

IMPLICATIONS

The increasing prevalence of CIPN demands an objective approach to identify at-risk patients in order to prevent or limit progression and effectively alleviate the symptoms associated with CIPN. An evidence base for novel targets and both pharmacological and non-pharmacological treatments is beginning to emerge and has been recognised recently in publications by the American Society of Clinical Oncology and analgesic trial design expert groups such as ACTTION.

Chemotherapy-induced peripheral neuropathy among patients with ovarian cancer

OBJECTIVE

To evaluate the course of chemotherapy-induced peripheral neuropathy (CIPN) among patients with ovarian cancer receiving taxanes.

METHODS

In a retrospective case-control study conducted between January 1, 2016, and May 31, 2018, in Xiangya Hospital in Changsha, China, women with ovarian cancer received taxane and platinum-complex combination therapy. The European Organization for Research and Treatment of Cancer Quality of Life, Ovarian cancer module questionnaire, was used to assess the severity of neuropathy by telephone.

RESULTS

Out of the 88 women included in the study, 61 (69.3%) reported CIPN. Twelve months after chemotherapy, the percentage was 19.3%. The percentage of patients suffering from sensory peripheral neuropathy (SPN) was higher than motor peripheral neuropathy at any time during the study. Sensory peripheral neuropathy was associated with the use of docetaxel and paclitaxel (docetaxel vs liposomal paclitaxel: odds ratio [OR] 4.39, 95% confidence interval [CI] 1.69-11.42, P<0.01; paclitaxel vs liposomal paclitaxel: OR 5.91, 95% CI 1.09-31.97, P=0.04). The average weakness score in acute CIPN was lower than chronic CIPN (1.46 vs 2.00, P=0.019). Patients treated with vitamin B₁ and amifostine experienced better relief from CIPN.

CONCLUSION

The present study showed a significant proportion of patients with ovarian cancer receiving taxanes suffered from long-term residual neuropathy, and the use of docetaxel and paclitaxel was associated with SPN. Vitamin B₁ or amifostine may improve the symptoms of CIPN.

Relief of eribulin-associated malaise by l-glutamine in two patients with uterine leiomyosarcoma: a case report

Eribulin (ERI) treatment for leiomyosarcoma causes unexplained malaise and reduced quality of life (QoL) in about 40% of patients. There have been few reports suggesting the risk factors for occurrence of eribulin-associated malaise or effective treatment, whereas our present report focuses on this issue. We encountered two patients with advanced or recurrent uterine leiomyosarcoma who experienced severe malaise while receiving ERI therapy (ERI 1.4 mg/m² on days 1 and 8 of each 21-days cycle). We retrospectively reviewed these cases to examine the time of onset and change in the severity of malaise, and the change in QoL before and after ERI therapy. The first patient was a 70-year-old woman with severe malaise 3-6 days after ERI administration on day 1 of treatment. Malaise temporarily improved, but ERI resumption on day 8 caused severe malaise relapse on days 11-13. The second patient was a 58-year-old woman with severe malaise on days 4-5 and 11-12 of treatment. QoL worsened by the development of malaise. A bimodal pattern of malaise development was observed during ERI therapy, corresponding to 3-6 days after the administration of ERI. The pattern of malaise development in the present two patients treated with ERI was similar to that of myalgia in paclitaxel-treated patients. Both patients received l-glutamine/azulene combination for gastritis symptoms starting from cycle 2, relieving malaise, resulting in an improvement in the QoL score. Results from future prospective studies will be used to determine whether or not l-glutamine can alleviate ERI-caused malaise and improve the QoL of patients.

Integrative Approaches to Chemotherapy-Induced Peripheral Neuropathy

PURPOSE OF REVIEW

Chemotherapy-induced peripheral neuropathy (CIPN) is a common complication of cancer treatment, with conventional treatment limited in its ability for prevention or treatment of symptoms. This review addresses the research assessing the effectiveness and safety of complementary and integrative medicine (CIM) in preventing and treating CIPN-related symptoms.

RECENT FINDINGS

The CIM modalities acupuncture, classical massage, omega-3 fatty acids, and the Japanese Kampo medicine Goshanjishen may be of benefit in preventing or treating CIPN. Vitamin E (alpha-tocopherol), glutamine/glutamate, alpha-lipoic acid, and acetyl-L-carnitine (ALCAR) are not, with ALCAR increasing symptom severity and vitamin E the risk for developing prostate cancer. CIM therapies with a potential for preventing or treating CIPN-related symptoms should be further investigated. CIM is considered safe when provided within an integrative oncology setting, under the guidance and supervision of an integrative physician.

Targeting strategies for chemotherapy-induced peripheral neuropathy: does gut microbiota play a role?

Chemotherapy-induced peripheral neuropathy (CIPN) is a progressive, often irreversible condition that produces severe neurological deficits. Emerging data suggest that chemotherapy also exerts detrimental effects on gut microbiota composition and intestinal permeability, contributing to dysbiosis and inflammation. Compared with other complications associated with chemotherapy, such as diarrhoea and mucositis, CIPN is of particular concern because it is the most common reason for terminating or suspending treatment. However, specific and effective curative treatment strategies are lacking. In this review, we provide an update on current preclinical and clinical understandings about the role of gut microbiota in CIPN. The gut microbiota serves as an intersection between the microbiome-gut-brain and the neuroimmune-endocrine axis, forming a complex network that can directly or indirectly affect key components involved in the manifestations of CIPN. Herein, we discuss several potential mechanisms within the context of the networks and summarize alterations in gut microbiome induced by chemotherapeutic drugs, providing great potential for researchers to target pathways associated with the gut microbiome and overcome CIPN.

Prevention and Treatment for Chemotherapy-Induced Peripheral Neuropathy: Therapies Based on CIPN Mechanisms

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a progressive, enduring, and often irreversible adverse effect of many antineoplastic agents, among which sensory abnormities are common and the most suffering issues. The pathogenesis of CIPN has not been completely understood, and strategies for CIPN prevention and treatment are still open problems for medicine.

OBJECTIVES

The objective of this paper is to review the mechanism-based therapies against sensory abnormities in CIPN.

METHODS

This is a literature review to describe the uncovered mechanisms underlying CIPN and to provide a summary of mechanism-based therapies for CIPN based on the evidence from both animal and clinical studies.

RESULTS

An abundance of compounds has been developed to prevent or treat CIPN by blocking ion channels, targeting inflammatory cytokines and combating oxidative stress. Agents such as glutathione, mangafodipir and duloxetine are expected to be effective for CIPN intervention, while Ca/Mg infusion and venlafaxine, tricyclic antidepressants, and gabapentin display limited efficacy for preventing and alleviating CIPN. And the utilization of erythropoietin, menthol and amifostine needs to be cautious regarding to their side effects.

CONCLUSIONS

Multiple drugs have been used and studied for decades, their effect against CIPN are still controversial according to different antineoplastic agents due to the diverse manifestations among different antineoplastic agents and complex drug-drug interactions. In addition, novel therapies or drugs that have proven to be effective in animals require further investigation, and it will take time to confirm their efficacy and safety.

Incidence of Neuropathy with Weekly Paclitaxel and Role of Oral Glutamine Supplementation for Prevention of Paclitaxel Induced Peripheral Neuropathy Randomized Controlled Trial

Background: Peripheral neuropathy is damage to the peripheral nerve. The most common cause of neuropathy is paclitaxel. Several avenues have been explored to ameliorate the neurotoxicity associated with paclitaxel. Clinical studies have assessed the efficacy of glutamine with different doses and schedules to prevent gastrointestinal toxicity (mucositis, diarrhea) and peripheral neuropathy in patients receiving a variety of chemotherapy agents or radiation therapy and found that glutamine can prevent paclitaxel-induced peripheral neuropathy. Methods: Total of 50 patients, aged 30 or more with diagnosis of cancer and fulfilling the inclusion and exclusion criteria, formed the study population. We assigned 25 patients to the glutamine group and 25 patients to no glutamine group. All patients received weekly paclitaxel. Results:: The incidence of neuropathy of all grades at 3 months was 78% and at 6 months was 80%.In this study, most common symptom reported was numbness in toes (74%). In this study, Grade 1 was the most common grade of symptom reported by the patient (40%–50%). 2nd, 3rd, and 4th most common grade of symptom reported by the patient was Grade 0, Grade 2, and Grade 3, respectively. There was no Grade 4 symptom reported by any patient. All the symptoms were statistically comparable in both groups (Myalgias: P = 0.066, Arthralgia: P = 0.93, Dysesthesia: P = 0.82, Paresthesia: P = 0.92, Numbness fingers: P = 0.97, Numbness toes: P = 0.60). In our study, there was no incidence of cranial nerve weakness or any incidence of the postural drop. The electrophysiological study is the best tool available and can detect neuropathy at the very earlier stage even when the clinical exam is negative. Apart from that nature of neuropathy can be determined but grading is not possible which makes very difficult to decide on follow-up examinations when the physician should intervene. Moreover, there are fluctuations in SNAP and CMAP, and these fluctuations are most probably related to the innate variability of serial nerve conduction study parameters, particularly motor and sensory amplitude. Glutamine did not prevent neurotoxicity induced by weekly paclitaxel.

Pharmacometabolomics reveals a role for histidine, phenylalanine, and threonine in the development of paclitaxel-induced peripheral neuropathy

PURPOSE

Approximately 25% of breast cancer patients experience treatment delays or discontinuation due to paclitaxel-induced peripheral neuropathy (PN). Currently, there are no predictive biomarkers of PN. Pharmacometabolomics is an informative tool for biomarker discovery of drug toxicity. We conducted a secondary whole blood pharmacometabolomics analysis to assess the association between pretreatment metabolome, early treatment-induced metabolic changes, and the development of PN.

METHODS

Whole blood samples were collected pre-treatment (BL), just before the end of the first paclitaxel infusion (EOI), and 24 h after the first infusion (24H) from sixty patients with breast cancer receiving (80 mg/m²) weekly treatment. Neuropathy was assessed at BL and prior to each infusion using the sensory subscale (CIPN8) of the EORTC CIPN20 questionnaire. Blood metabolites were quantified from 1-D-¹H-nuclear magnetic resonance spectra using Chenomx® software. Metabolite concentrations were normalized in preparation for Pearson correlation and one-way repeated measures ANOVA with multiple comparisons corrected by false discovery rate (FDR).

RESULTS

Pretreatment histidine, phenylalanine, and threonine concentrations were inversely associated with maximum change in CIPN8 (ΔCIPN8) (p < 0.02; FDR ≤ 25%). Paclitaxel caused a significant change in concentrations of 2-hydroxybutyrate, 3-hydroxybutyrate, pyruvate, o-acetylcarnitine, and several amino acids from BL to EOI and/or 24H (p < 0.05; FDR ≤ 25%), although these changes were not associated with ΔCIPN8.

CONCLUSIONS

Whole blood metabolomics is a feasible approach to identify potential biomarker candidates of paclitaxel-induced PN. The findings suggest that pretreatment concentrations of histidine, phenylalanine, and threonine may be predictive of the severity of future PN and paclitaxel-induced metabolic changes may be related to disruption of energy homeostasis.

Taxanes and platinum derivatives impair Schwann cells via distinct mechanisms

Impairment of peripheral neurons by anti-cancer agents, including taxanes and platinum derivatives, has been considered to be a major cause of chemotherapy-induced peripheral neuropathy (CIPN), however, the precise underlying mechanisms are not fully understood. Here, we examined the direct effects of anti-cancer agents on Schwann cells. Exposure of primary cultured rat Schwann cells to paclitaxel (0.01 μM), cisplatin (1 μM), or oxaliplatin (3 μM) for 48 h induced cytotoxicity and reduced myelin basic protein expression at concentrations lower than those required to induce neurotoxicity in cultured rat dorsal root ganglion (DRG) neurons. Similarly, these anti-cancer drugs disrupted myelin formation in Schwann cell/DRG neuron co-cultures without affecting nerve axons. Cisplatin and oxaliplatin, but not paclitaxel, caused mitochondrial dysfunction in cultured Schwann cells. By contrast, paclitaxel led to dedifferentiation of Schwann cells into an immature state, characterized by increased expression of p75 and galectin-3. Consistent with in vitro findings, repeated injection of paclitaxel increased expression of p75 and galectin-3 in Schwann cells within the mouse sciatic nerve. These results suggest that taxanes and platinum derivatives impair Schwan cells by inducing dedifferentiation and mitochondrial dysfunction, respectively, which may be important in the development of CIPN in conjunction with their direct impairment in peripheral neurons.

Pathophysiology of Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced neuropathy is a common, dose-dependent adverse effect of several antineoplastics. It can lead to detrimental dose reductions and discontinuation of treatment, and severely affects the quality of life of cancer survivors. Clinically, chemotherapy-induced peripheral neuropathy presents as deficits in sensory, motor, and autonomic function which develop in a glove and stocking distribution due to preferential effects on longer axons. The pathophysiological processes are multi-factorial and involve oxidative stress, apoptotic mechanisms, altered calcium homeostasis, axon degeneration and membrane remodeling as well as immune processes and neuroinflammation. This review focusses on the commonly used antineoplastic substances oxaliplatin, cisplatin, vincristine, docetaxel, and paclitaxel which interfere with the cancer cell cycle-leading to cell death and tumor degradation-and cause severe acute and chronic peripheral neuropathies. We discuss drug mechanism of action and pharmacokinetic disposition relevant to the development of peripheral neuropathy, the epidemiology and clinical presentation of chemotherapy-induced neuropathy, emerging insight into genetic susceptibilities as well as current understanding of the pathophysiology and treatment approaches.

The Markers of Glutamate Metabolism in Peripheral Blood Mononuclear Cells and Neurological Complications in Lung Cancer Patients

Objective. To evaluate the involvement of glutamate metabolism in peripheral blood mononuclear cells (PBMC) in the development of neurological complications in lung cancer and during chemotherapy. Methods. The prospective study included 221 lung cancer patients treated with chemotherapeutics. Neurological status and cognitive functions were evaluated at baseline and after 6-month follow-up. Glutamate level, the activities of glutaminase- (GLS-) glutamate synthetizing enzyme, glutamate dehydrogenase (GDH), and glutamate decarboxylase catalyzing glutamate degradation were analyzed in PBMC and in sera of lung cancer patients by means of spectrophotometric and colorimetric methods. Results. Chemotherapy of lung neoplasms induced increase of glutamate content in PBMC and its concentration in serum increased the activity of GDH in PBMC and decreased activity of glutaminase in PBMC. The changes in glutamate metabolism markers were associated with initial manifestation of neurological deficit in lung cancer patients and with new symptoms, which appear as a complication of chemotherapy. Moreover, the analyzed parameters of glutamate control correlated with a spectrum of cognitive functions measures in lung cancer patients. Conclusion. We have demonstrated dysregulation in glutamate and glutamate metabolism controlling enzymes as promising indicators of risk for chemotherapy-induced neurological complications in lung cancer patients with particular emphasis on cognitive impairment.

Glutamine for the treatment of vincristine-induced neuropathy in children and adolescents with cancer

BACKGROUND

Vincristine is an integral treatment component of many childhood tumors with potentially dose-limiting sensory and/or motor neuropathy. Results from a pilot study on the incidence of vincristine-induced peripheral neuropathy (VIPN) as well as the efficacy and safety of glutamine in reducing signs and symptoms of VIPN in children with cancer are presented.

METHODS

Fifty-six patients between the ages of 5-21 with newly diagnosed leukemia, lymphoma, extracranial solid tumor or medulloblastoma and expected to receive a minimum cumulative dose of 6 mg/m² of vincristine over a 30-week period were eligible. Patients' neurological functioning was monitored every 3 weeks using clinical history, exam, and assessment of motor functioning. Upon identification of neuropathy, patients were randomized to either glutamine (6 g/m² per dose twice daily, maximum 10 g/dose) or placebo for a 3-week period followed by 3-week wash out period (Time 3).

RESULTS

Forty-nine patients were fully evaluable and 100 % developed neuropathy per study definitions. No significant differences in demographics or side effects were noted between the randomized groups. The distribution of sensory neuropathy scores between the two groups was statistically significant after the intervention (p = 0.022). Children receiving glutamine also rated their quality of life (QoL) as 8.42 points higher on the PedsQL total score than those receiving placebo (p = 0.031).

CONCLUSIONS

Glutamine supplementation is well tolerated and associated with improvements in sensory function and self-reported overall quality of life. Future studies are warranted to confirm the efficacy of glutamine for the treatment of vincristine-related sensory neuropathy in pediatric cancer patients.

The effect of glutamine intake on complications of colorectal and colon cancer treatment: A systematic review

Background:

Improvement in complications of antitumor agents and surgery is important to enhance life quality and survival among patients with colon and colorectal cancer. It has been reported that some dietary components such as glutamine (Gln) have beneficial effects on these complications of cancer therapies. However, the results of studies are inconsistent in this area. We performed a review on randomized controlled trials (RCTs) evaluating the effects of Gln intake on complications related to therapeutic strategies of the colon and colorectal cancer.

Materials and Methods:

A systematic search was conducted in PubMed, Google Scholar, Cochrane Library, and SID databases to find the relevant literature, published before July 2015.

Results:

Nine RCTs of 217 screened articles were included in this systematic review. The results of the present review suggested that Gln intake among colon and colorectal cancer patients could reduce some complications induced by chemotherapy such as gut mucositis and diarrhea and improve nitrogen balance, immune system and wound healing after surgery, whereas benefits role of Gln on radiochemotherapy side effects were not provided.

Conclusion:

The role of Gln intake on some improvement of complications induced by cancer therapeutic methods and shorten the length of hospital stay may be promising and one that is worthy of further exploration.

New Insights into Potential Prevention and Management Options for Chemotherapy-Induced Peripheral Neuropathy

OBJECTIVE

Neurological complications such as chemotherapy-induced peripheral neuropathy (CIPN) and neuropathic pain are frequent side effects of neurotoxic chemotherapy agents. An increasing survival rate and frequent administration of adjuvant chemotherapy treatments involving neurotoxic agents makes it imperative that accurate diagnosis, prevention, and treatment of these neurological complications be implemented.

METHODS

A consideration was undertaken of the current options regarding protective and treatment interventions for patients undergoing chemotherapy with neurotoxic chemotherapy agent or experience with CIPN. Current knowledge on the mechanism of action has also been identified. The following databases PubMed, the Cochrane Library, Science Direct, Scopus, EMBASE, MEDLINE, CINAHL, CNKI, and Google Scholar were searched for relevant article retrieval.

RESULTS

A range of pharmaceutical, nutraceutical, and herbal medicine treatments were identified that either showed efficacy or had some evidence of efficacy. Duloxetine was the most effective pharmaceutical agent for the treatment of CIPN. Vitamin E demonstrated potential for the prevention of cisplatin-IPN. Intravenous glutathione for oxaliplatin, Vitamin B6 for both oxaliplatin and cisplatin, and omega 3 fatty acids for paclitaxel have shown protection for CIPN. Acetyl-L-carnitine may provide some relief as a treatment option. Acupuncture may be of benefit for some patients and Gosha-jinki-gan may be of benefit for protection from adverse effects of oxaliplatin induced peripheral neuropathy.

CONCLUSIONS

Clinicians and researchers acknowledge that there are numerous challenges involved in understanding, preventing, and treating peripheral neuropathy caused by chemotherapeutic agents. New insights into mechanisms of action from chemotherapy agents may facilitate the development of novel preventative and treatment options, thereby enabling medical staff to better support patients by reducing this debilitating side effect.

Taxane induced neuropathy in patients affected by breast cancer: Literature review

Taxane induced neuropathy (TIN) is the most limiting side effect of taxane based chemotherapy, relative to the majority of breast cancer patients undergoing therapy with both docetaxel and paclitaxel. The symptoms begin symmetrically from the toes, because the tips of the longest nerves are affected for first. The patients report sensory symptoms such as paresthesia, dysesthesia, numbness, electric shock-like sensation, motor impairment and neuropathic pain. There is a great inter-individual variability among breast cancer women treated with taxanes, in fact 20-30% of them don't develop neurotoxicity. Actually, there is no standard therapy for TIN, although many medications, antioxidants and natural substances have been tested in vitro and in vivo. We will summarize all most recent literature data on TIN prevention and treatment, in order to reach an improvement in TIN management. Further studies are needed to evaluate new therapies that restore neuronal function and improve life quality of patients.

Chemotherapy dose reduction due to chemotherapy induced peripheral neuropathy in breast cancer patients receiving chemotherapy in the neoadjuvant or adjuvant settings: a single-center experience

Purpose

Taxanes are a cornerstone treatment in early and advanced stage breast cancer and in other common solid tumor malignancies; however, the development of chemotherapy induced peripheral neuropathy (CIPN) often necessitates dose-reduction, which may hamper the effectiveness of the drug and compromise survival outcomes especially when used in the adjuvant setting. Limited literature is available on the prevalence and severity of dose reduction due to CIPN. We sought to determine the frequency and severity of CIPN-induced dose reduction in early stage breast cancer patients who received taxane-based chemotherapy in the neoadjuvant or adjuvant settings.

Methods

We conducted a retrospective single-institution breast cancer clinic chart review of 123 newly diagnosed breast cancer patients and treated with taxane-based neoadjuvant/adjuvant chemotherapy at the University of Maryland Greenebaum Cancer Center between January 2008 and December 2011.

Results

Forty-nine of 123 (40%; 95% CI: 31-49%) patients required dose reduction. Twenty-one (17%; 95% CI: 11-25%) of these patients were dose-reduced specifically due to CIPN that developed during treatment. The median relative dose intensity (received dose/planned dose) for the 21 CIPN-induced dose reduction patients was 73.4% (range, 68.0-94.0%). Patients with diabetes appeared to have a higher risk of taxane-induced dose reduction (p-value=0.01). African-American patients and those treated with paclitaxel (rather than docetaxel) experienced a higher-risk of CIPN-induced dose reduction (p-values are <0.001 and 0.001, respectively).

Conclusions

The incidence of CIPN-associated dose reduction in our patient population was 17%. African-American patients, diabetics and subjects treated with paclitaxel had a higher risk for CIPN-associated dose reduction in our study.

Toxic and drug-induced peripheral neuropathies: updates on causes, mechanisms and management

PURPOSE OF REVIEW

This review discusses publications highlighting current research on toxic, chemotherapy-induced peripheral neuropathies (CIPNs), and drug-induced peripheral neuropathies (DIPNs).

RECENT FINDINGS

The emphasis in clinical studies is on the early detection and grading of peripheral neuropathies, whereas recent studies in animal models have given insights into molecular mechanisms, with the discovery of novel neuronal, axonal, and Schwann cell targets. Some substances trigger inflammatory changes in the peripheral nerves. Pharmacogenetic techniques are underway to identify genes that may help to predict individuals at higher risk of developing DIPNs. Several papers have been published on chemoprotectants; however, to date, this approach has not been shown effective in clinical trials.

SUMMARY

Both length and nonlength-dependent neuropathies are encountered, including small-fiber involvement. The introduction of new diagnostic techniques, such as excitability studies, skin laser Doppler flowmetry, and pharmacogenetics, holds promise for early detection and to elucidate underlying mechanisms. New approaches to improve functions and quality of life in CIPN patients are discussed. Apart from developing less neurotoxic anticancer therapies, there is still hope to identify chemoprotective agents (erythropoietin and substances involved in the endocannabinoid system are promising) able to prevent or correct painful CIPNs.

Chemotherapy-induced peripheral neuropathy in adults: a comprehensive update of the literature

Commonly used chemotherapeutic agents in oncology/hematology practice, causing toxic peripheral neuropathy, include taxanes, platinum compounds, vinca alkaloids, proteasome inhibitors, and antiangiogenic/immunomodulatory agents. This review paper intends to put together and discuss the spectrum of chemotherapy-induced peripheral neuropathy (CIPN) characteristics so as to highlight areas of future research to pursue on the topic. Current knowledge shows that the pathogenesis of CIPN still remains elusive, mostly because there are several sites of involvement in the peripheral nervous system. In any case, it is acknowledged that the dorsal root ganglia of the primary sensory neurons are the most common neural targets of CIPN. Both the incidence and severity of CIPN are clinically under- and misreported, and it has been demonstrated that scoring CIPN with common toxicity scales is associated with significant inter-observer variability. Only a proportion of chemotherapy-treated patients develop treatment-emergent and persistent CIPN, and to date it has been impossible to predict high-and low-risk subjects even within groups who receive the same drug regimen. This issue has recently been investigated in the context of pharmacogenetic analyses, but these studies have not implemented a proper methodological approach and their results are inconsistent and not really clinically relevant. As such, a stringent approach has to be implemented to validate that information. Another open issue is that, at present, there is insufficient evidence to support the use of any of the already tested chemoprotective agents to prevent or limit CIPN. The results of comprehensive interventions, including clinical, neurophysiological, and pharmacogenetic approaches, are expected to produce a consistent advantage for both doctors and patients and thus allow the registration and analysis of reliable data on the true characteristics of CIPN, eventually leading to potential preventive and therapeutic interventions.

Chemotherapy-induced peripheral neurotoxicity: a critical analysis

With a 3-fold increase in the number of cancer survivors noted since the 1970s, there are now over 28 million cancer survivors worldwide. Accordingly, there is a heightened awareness of long-term toxicities and the impact on quality of life following treatment in cancer survivors. This review will address the increasing importance and challenge of chemotherapy-induced neurotoxicity, with a focus on neuropathy associated with the treatment of breast cancer, colorectal cancer, testicular cancer, and hematological cancers. An overview of the diagnosis, symptomatology, and pathophysiology of chemotherapy-induced peripheral neuropathy will be provided, with a critical analysis of assessment strategies, neuroprotective approaches, and potential treatments. The review will concentrate on neuropathy associated with taxanes, platinum compounds, vinca alkaloids, thalidomide, and bortezomib, providing clinical information specific to these chemotherapies.

Chemotherapy-Induced Peripheral Neuropathy in Pediatric Cancer Patients

Chemotherapy-induced peripheral neuropathies (CIPNs) are an increasingly common neuropathic and pain syndrome in adult and pediatric cancer patients and survivors [1-69]. However, symptoms associated with CIPNs are often undiagnosed, under-assessed, and communications problems between clinicians, family members, and patients have been observed [70-73]. Less is known about the prevalence and impact of CIPNs on pediatric cancer populations [70-71]. This article aims to provide a brief understanding of CIPNs in pediatric populations, and to review the evidence for both its prevention and treatment.

Nutraceuticals and chemotherapy induced peripheral neuropathy (CIPN): a systematic review

Chemotherapy induced peripheral neuropathy [CIPN] is a common significant and debilitating side effect resulting from the administration of neurotoxic chemotherapeutic agents. These pharmaco-chemotherapeutics can include taxanes, vinca alkaloids and others. Moderate to severe CIPN significantly decreases the quality of life and physical abilities of cancer patients and current pharmacotherapy for CIPN e.g. Amifostine and antidepressants have had limited efficacy and may themselves induce adverse side effects. To determine the potential use of nutraceuticals i.e. vitamin E, acetyl-L-carnitine, glutamine, glutathione, vitamin B6, omega-3 fatty acids, magnesium, calcium, alpha lipoic acid and n-acetyl cysteine as adjuvants in cancer treatments a systematic literature review was conducted. Revised clinical studies comprised of randomized clinical trials that investigated the anti-CIPN effect of nutraceuticals as the adjuvant intervention in patients administered chemotherapy. Twenty-four studies were assessed on methodological quality and limitations identified. Studies were mixed in their recommendations for nutraceuticals. Currently no agent has shown solid beneficial evidence to be recommended for the treatment or prophylaxis of CIPN. The standard of care for CIPN includes dose reduction and/or discontinuation of chemotherapy treatment. The management of CIPN remains an important challenge and future studies are warranted before recommendations for the use of supplements can be made.

Non-herbal nutritional supplements for symptom relief in adjuvant breast cancer: creating a doctor-patient dialogue

Patients with breast cancer frequently turn to complementary medical therapies, including non-herbal nutritional supplements (NHNS). A number of NHNS products have been shown to potentially reduce the incidence and severity of adjuvant treatment-related symptoms. We review the literature and summarise the potential beneficial effects of these products and address issues regarding the safety of this practice. We offer an evidence-based approach for advancing a dialogue between doctors and patients interested in NHNS for adjuvant treatment-related toxicities. Taxane agents such as paclitaxel are frequently complicated by peripheral sensory neuropathy. The findings from several studies suggest that supplementation with vitamin E, glutamine and acetyl-L-carnithine may reduce the incidence and severity of paclitaxel-induced neuropathy. Glutamine has also been shown to reduce the incidence and severity of chemotherapy-induced and radiation-induced oral mucositis. Selenium can reduce upper limb lymphoedema following surgery and radiation treatments, and an antioxidant supplement has exhibited a protective effect against radiation-induced dermatitis. Finally, vitamin D has been shown to be effective in reducing the incidence and severity of arthralgia resulting from treatment with the aromatase inhibitor letrozole. The use of coenzyme Q10 was not found to be of benefit for cancer-related fatigue. There is a need to develop an open and non-judgmental dialogue between doctors and their patients with breast cancer, respecting the needs of the patient while addressing issues related to the efficacy and safety of NHNS products. Referral of patients to an integrative medicine consultant may help achieve these goals.

Glutamine: A novel approach to chemotherapy-induced toxicity

Treatment of cancer is associated with short- and long-term side-effects. Cancer produces a state of glutamine deficiency, which is further aggravated by toxic effects of chemotherapeutic agents leading to increased tolerance of tumor to chemotherapy as well as reduced tolerance of normal tissues to the side-effects of chemotherapy. This article reviews the possible role of glutamine supplementation in reducing the serious adverse events in patients treated with anticancer drugs. The literature related to the possible role of glutamine in humans with cancer and the supportive evidence from animal studies was reviewed. Searches were made and the literature was retrieved using PUBMED, MEDLINE, COCHRANE LIBRARY, CENAHL and EMBASE, with a greater emphasis on the recent advances and clinical trials. Glutamine supplementation was found to protect against radiation-induced mucositis, anthracycline-induced cardiotoxicity and paclitaxel-related myalgias/arthralgias. Glutamine may prevent neurotoxicity of paclitaxel, cisplatin, oxaplatin bortezomib and lenolidamide, and is beneficial in the reduction of the dose-limiting gastrointestinal toxic effects of irinotecan and 5-FU-induced mucositis and stomatitis. Dietary glutamine reduces the severity of the immunosuppressive effect induced by methotrexate and improves the immune status of rats recovering from chemotherapy. In patients with acute myeloid leukemia requiring parenteral nutrition, glycyl-glutamine supplementation could hasten neutrophil recovery after intensive myelosuppressive chemotherapy. Current data supports the usefulness of glutamine supplementation in reducing complications of chemotherapy; however, paucity of clinical trials weakens the clear interpretation of these findings.

Clinical trials in integrative therapies

OBJECTIVES

To review clinical trials in natural products and mind-body therapies for oncology symptom management, to discuss issues related to developing clinical trials in this area, and outline examples of rigorous and innovative study design.

DATA SOURCES

Peer reviewed literature.

CONCLUSION

Most of the evidence for the integrative therapies reviewed is derived from phase II trials, and is considered preliminary. More research is needed in these therapies to clearly articulate their role in the management of oncology symptoms. Innovative strategies and methodologies for studying integrative therapies have been demonstrated.

IMPLICATIONS FOR NURSING PRACTICE

It is necessary to critically evaluate the literature to be able to educate patients about integrative therapies. Investigators should expand on well-designed studies that demonstrate clinically important effects. Dissemination trials may be a good strategy, once data exists, to move integrative therapies into the care of patients.

Chemotherapy-induced peripheral neuropathy in pediatric cancer patients

Chemotherapy forms the backbone of treatment for many types of pediatric cancers, but a main side effect of treatment is chemotherapy-induced peripheral neuropathy (CIPN). Damage to the peripheral nervous system by chemotherapeutic agents can occur at the axon, cell body, or myelin level, and the mechanism of damage differs based on the specific chemotherapeutic agent used. This review provides background on the current knowledge of pathophysiology, assessment, and intervention for CIPN, focusing specifically on issues relevant in pediatric cancers patients. Although specific, standardized measures of CIPN are available for adults, such measures are limited for use in the pediatric populations. Likewise, clinical trials for prevention and treatment of this neuropathy and related symptoms are rare in pediatrics, but some information can be gained from the basic and adult literature.

Chemotherapy-induced peripheral neuropathy: prevention and treatment

Chemotherapy-induced peripheral neuropathy (CIPN) is a common, dose-limiting side effect of many chemotherapeutic agents. Although many therapies have been investigated for the prevention and/or treatment of CIPN, there is no well-accepted proven therapy. In addition, there is no universally accepted, well-validated measure for the assessment of CIPN. The agents for which there are the strongest preliminary data regarding their potential efficacy in preventing CIPN are intravenous calcium and magnesium (Ca/Mg) infusions and glutathione. Agents with the strongest supporting evidence for efficacy in the treatment of CIPN include topical pain relievers, such as baclofen/amitriptyline/ketamine gel, and serotonin and norepinephrine reuptake inhibitors, such as venlafaxine and duloxetine. Other promising therapies are also reviewed in this paper. Cutaneous electrostimulation is a nonpharmacological therapy that appears, from an early pilot trial, to be potentially effective in the treatment of CIPN. Finally, there is a lack of evidence of effective treatments for the paclitaxel acute pain syndrome (P-APS), which appears to be caused by neurologic injury.

Peripheral neuropathy with microtubule-targeting agents: occurrence and management approach

Microtubule-targeting agents (MTAs), which include vinca alkaloids, taxanes, and the recently introduced epothilone, ixabepilone, are widely used chemotherapeutic agents for treatment of patients with cancer. MTAs interfere with the normal structure and function of microtubules, leading to cell-cycle arrest and tumor cell death. Microtubule function is critical to normal neuronal function, thus MTA therapy is commonly associated with some form of neuropathy. There is poor agreement between tools for clinical assessment of MTA-associated peripheral neuropathy, and standardization of grading scales is needed to reduce variability. For a majority of patients, MTA-associated neuropathy is mild to moderate in intensity and reversible, but it can be severe and resolve incompletely. The incidence and severity of MTA-associated neuropathy is drug, dose, and schedule dependent. The first-generation vinca alkaloids (eg, vincristine) are associated with severe mixed sensory and motor neuropathy, whereas the newer vinca alkaloids (eg, vinorelbine, vinflunine) induce a milder sensory neuropathy. Taxane-associated sensory neuropathy occurs more often with standard (polyoxyethylated castor oil-based) and albumin-bound paclitaxel than with docetaxel. The incidence and presentation of peripheral neuropathy with ixabepilone, alone or in combination with capecitabine, are similar to that with taxanes. Management of neuropathy may involve reducing or delaying the MTA dose, or in severe persistent or disabling cases discontinuing treatment. Reversal of neuropathy after dosage intervention appears to be more rapid with ixabepilone than with other MTAs.

A trial to assess the efficacy of glutamic acid in prevention of vincristine-induced neurotoxicity in pediatric malignancies: a pilot study

Vincristine is considered as a backbone of therapy in the induction and consolidation phases of pediatric malignancies. Neurotoxicity is a principal side effect of its use. This study is a randomized single-blinded placebo-controlled clinical trial to evaluate the role of glutamic acid in ameliorating neurotoxicity in pediatric patients with hematologic and solid tumors receiving vincristine during induction course. Fifty-four patients in the glutamic acid group received glutamic acid 1.5 grams daily orally in 3 divided doses during the 4-week induction with vincristine in a dose of 1.5 mg/m² IV weekly. Placebo group (40 patients) received oral placebo 3 times daily in the same way as the glutamic acid group. The onset of neurotoxicity was significantly earlier in placebo group than in glutamic acid group regarding tendon Achilles reflex, Patellar reflex, parasthesia, and increased frequency of constipation. This was statistically significant mostly in third and fourth visits, no severe cases of strength and mental alteration side effects in both groups. Glutamic acid was well tolerated with no gastrointestinal side effects in patients. This study suggests that the coadministration of oral glutamic acid with repetitive intravenous bolus injections of vincristine resulted in a reduction of its neurotoxicity.

The use of vitamin E for the prevention of chemotherapy-induced peripheral neuropathy: results of a randomized phase III clinical trial

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) continues to be a substantial problem for many cancer patients. Pursuant to promising appearing pilot data, the current study evaluated the use of vitamin E for the prevention of CIPN.

METHODS

A phase III, randomized, double-blind, placebo-controlled study was conducted in patients undergoing therapy with neurotoxic chemotherapy, utilizing twice daily dosing of vitamin E (400 mg)/placebo. The primary endpoint was the incidence of grade 2+ sensory neuropathy (SN) toxicity (CTCAE v 3.0) in each treatment arm, analyzed by chi-square testing. Planned sample size was 100 patients per arm to provide 80% power to detect a difference in incidence of grade 2+ SN toxicity from 25% in the placebo group to 10% in the vitamin E group.

RESULTS

Two-hundred seven patients were enrolled between December 1, 2006 and December 14, 2007, producing 189 evaluable cases for analysis. Cytotoxic agents included taxanes (109), cisplatin (8), carboplatin (2), oxaliplatin (50), or combination (20). There was no difference in the incidence of grade 2+ SN between the two arms (34%-vitamin E, 29%-placebo; P = 0.43). There were no significant differences between treatment arms for time to onset of neuropathy (P = 0.58), for chemotherapy dose reductions due to neuropathy (P = 0.21), or for secondary endpoints derived from patient-reported neuropathy symptom assessments. The treatment was well tolerated overall.

CONCLUSIONS

Vitamin E did not appear to reduce the incidence of sensory neuropathy in the studied group of patients receiving neurotoxic chemotherapy.

Phase II study evaluating the efficacy and safety of sagopilone (ZK-EPO) in patients with metastatic breast cancer that has progressed following chemotherapy

Sagopilone is a novel, fully synthetic epothilone that has shown promising preclinical activity in a range of tumor models, including platinum-resistant ovarian cancer and metastatic breast cancer (MBC). This open-label, multicenter, Phase II study investigated the efficacy, safety, and tolerability of sagopilone administered to patients with MBC. Women with MBC whose previous chemotherapy regimen included a taxane and an anthracycline received sagopilone 16 or 22 mg/m(2) as a 3-h intravenous infusion every 21 days. Efficacy (using modified Response Evaluation Criteria in Solid Tumors), safety, and tolerability were assessed in this population. A total of 65 patients received sagopilone at either 16 mg/m(2) (N = 39) or 22 mg/m(2) (N = 26). Patients received a median of two cycles of sagopilone. Among the 65 patients who were evaluable for efficacy, there were three confirmed tumor responses over both treatment arms; however, the primary target of the study was not reached. The main treatment-related adverse events were sensory neuropathy (81.5%) and fatigue (44.6%). There were no deaths related to the study drug. Sagopilone was moderately tolerated in both treatment arms and showed limited activity in heavily pre-treated patients with MBC.

Long-term glutamate supplementation failed to protect against peripheral neurotoxicity of paclitaxel

Toxic peripheral neuropathy is still a significant limiting factor for chemotherapy with paclitaxel (PAC), although glutamate and its closely related amino acid glutamine were claimed to ameliorate PAC neurotoxicity. This pilot trial aimed to evaluate the role of glutamate supplementation for preventing PAC-induced peripheral neuropathy in a randomized, placebo-controlled, double-blinded clinical and electro-diagnostic study. Forty-three ovarian cancer patients were available for analysis following six cycles of the same PAC-containing regimen: 23 had been supplemented by glutamate all along the treatment period, at a daily dose of three times 500 mg (group G), and 20 had received a placebo (group P). Patients were evaluated by neurological examinations, questionnaires and sensory-motor nerve conduction studies. There was no significant difference in the frequency of signs or symptoms between the two groups although neurotoxicity symptoms presented mostly with lower scores of severity in group G. However, this difference reached statistical significance only with regard to reported pain sensation (P = 0.011). Also the frequency of abnormal electro-diagnostic findings showed similarity between the two groups (G: 7/23 = 30.4%; P: 6/20 = 30%). This pilot study leads to the conclusion that glutamate supplementation at the chosen regimen fails to protect against peripheral neurotoxicity of PAC.