Oxaliplatin-induced neurotoxicity: acute hyperexcitability and chronic neuropathy

Duloxetine for the Prevention of Oxaliplatin Induced Peripheral Neuropathy: A Randomized, Placebo-Controlled, Double-blind Clinical Trial

PURPOSE

Peripheral neuropathy is a dose-limiting adverse effect of oxaliplatin. The aim of this study was to evaluate the efficacy and safety of duloxetine in the prevention of oxaliplatin-induced peripheral neuropathy (OIPN).

METHOD

Cancer patients receiving oxaliplatin based chemotherapy were randomized into two arms. Duloxetine 60 mg capsule was given in the first 14 days of each chemotherapy cycle to one arm and placebo was similarly given to another. We compared the two arms based on the incidence of neuropathy and the results of the nerve conduction study (NCS). Grade of complained neuropathy was recorded according to Common Terminology Criteria for Adverse Events (CTCAE).

RESULTS

Thirty-two patients mostly rectal cancer (90.6%) were randomized to duloxetine and placebo arms. Highest grade of neuropathy in each cycle was not significantly different between the two groups. Six weeks after treatment incidence of neuropathy of any grade was 52.9 in duloxetine arm compared to 76.9% in placebo arm (P: 0.26). Patients in the duloxetine arm had a lower percentage of chemotherapy cycles (mean) in which they reported distal paresthesia (51% vs. 84%, P = 0.01) and throat discomfort (37% vs. 69%, P = 0.01). Results of NCS were mostly comparable between the two arms except for the velocity in two of the examined nerve which was significantly higher in duloxetine group. Duloxetine was safe and well-tolerated.

CONCLUSION

Although a definite conclusion might be difficult to draw but administering duloxetine for 14 days in each chemotherapy cycle could not decrease the incidence of acute OIPN based on CTCAE grading system.

Falls during oxaliplatin-based chemotherapy for gastrointestinal malignancies - (lessons learned from) a prospective study

This prospective cohort study aimed to characterise the impact of oxaliplatin-based chemotherapy and its neurotoxic side effects (i.e., chemotherapy-induced neuropathy) on functional fall-risk and falls. Twenty chemotherapy-naïve participants (mean age, 59 years; 16 males) were consecutively included. A multimodal fall risk assessment was performed at four time points within 6 months. Polyneuropathy was assessed using the Neurologic Disability Scale; the fall risk was assessed by functional tests (Tinetti Test, Chair-Rising Test, and Timed up and Go Test). Patient-reported outcomes comprised the Hospitality Anxiety and Depression Scale (HADS), the Falls Efficacy Scale - International (FES-I) to assess the fear of falling, and the Physical Activity for the Elderly (PASE) questionnaire. Three falls occurred during the study. All fallen participants had a high fall risk-index (≥4 more risk factors) compared to only 30% of the non-fallen participants (p = 0.03) and suffered more frequently from pre-existing mild polyneuropathy (p = 0.049). Study discontinuation (n = 12) was associated with a higher rate of polypharmacy (p = 0.045), anxiety (HADS-A, p = 0.03), and specific fear of falling (FES-I, p = 0.025). In contrast, study completers (n = 8) reported an improvement in physical activity (PASE) (p = 0.018). In summary, pre-existing fall-risk factors impacted more falls than chemotherapy. A fall risk index offers a time-efficient screening option in an outpatient oncological setting.

First-in-Class Dual Hybrid Carbonic Anhydrase Inhibitors and Transient Receptor Potential Vanilloid 1 Agonists Revert Oxaliplatin-Induced Neuropathy

Here, we report for the first time a series of compounds potentially useful for the management of oxaliplatin-induced neuropathy (OINP) able to modulate the human Carbonic Anhydrases (hCAs) as well as the Transient Receptor Potential Vanilloid 1 (TRPV1). All compounds showed effective in vitro inhibition activity toward the main hCAs involved in such a pathology, whereas selected items reported moderate agonism of TRPV1. X-ray crystallographic experiments assessed the binding modes of the two enantiomers (R)-37a and (S)-37b within the hCA II cleft. Although the tails assumed diverse orientations, no appreciable effects were observed for their hCA II affinity. Similarly, the activity of (R)-39a and (S)-39b on TRPV1 was not influenced by the stereocenters. In vivo evaluation of the most promising derivatives (R)-12a, (R)-37a, and the two enantiomers (R)-39a, (S)-39b revealed antihypersensitivity effects in a mouse model of OINP with potent and persistent effect up to 75 min after administration.

Serum sodium ions and chloride ions associated with taxane-induced peripheral neuropathy in Chinese patients with early-stage breast cancer: A nation-wide multicenter study

BACKGROUND

Taxane-induced peripheral neuropathy (TIPN) is a debilitating adverse effect of cancer treatments with taxanes which may require a reduction or discontinuation chemotherapy and affect clinical and survival outcomes. A number of factors have contributed to the increasing prevalence of TIPN. Nonetheless, limited knowledge exists of potential prechemotherapy blood-based biochemical factors associated with TIPN development.

METHODS

We recruited breast cancer patients at seven cancer institutions in China. Participants aged 18 years or older with stage I to III breast cancer who scheduled to undergo primary neoadjuvant and adjuvant chemotherapy with taxanes were eligible. Eligible patients underwent patient-reported neuropathy assessments using the EORTC-CIPN20 questionnaire. Patients completed the questionnaire before commencing treatment and after every cycle. For every patient, we selected the highest TIPN toxicity score for analysis since the first cycle. The posttreatment TIPN severity was compared with blood-based biochemical factors within 30 days before commencing treatment. Independent samples t tests, Mann-Whitney U tests and linear regression were used to identify blood-based and clinical associations with TIPN development.

RESULTS

The study included 873 breast cancer participants who received paclitaxel, docetaxel or nanoparticle albumin-bound (nab)-paclitaxel. In the whole cohort, factors associated with higher TIPN toxicity scores were higher cumulative chemotherapy dose (β = 0.005; 95% CI, 0.004 to 0.006; P < .001), lower sodium ions (β = -0.24; 95% CI, -0.39 to -0.09; P = .002) and higher chloride ions (β = 0.30; 95% CI, 0.16 to 0.44; P < .001).

CONCLUSIONS

The findings suggest that breast cancer patients with a higher cumulative chemotherapy dose, lower pretreatment sodium ions, and higher pretreatment chloride ions receiving taxanes should receive closer monitoring to mitigate the development of short-term and long-term TIPN.

Supercritical fluid extract of Angelica sinensis promotes the anti-colorectal cancer effect of oxaliplatin

Oxaliplatin-based chemotherapy regimens are recommended for patients with advanced colorectal cancer (CRC). However, oxaliplatin (OXA) can cause toxic side effects at the recommended dosage. Therefore, it is necessary to find new drug candidates that can synergize with OXA and thereby lower the OXA dose while still maintaining its efficacy. Angelica sinensis is a common drug in traditional Chinese medicine and has demonstrated a significant anti-CRC effect in modern pharmacological studies. The active ingredients in Angelica sinensis can be effectively extracted by a supercritical fluid extract. In this study, the supercritical fluid extract of Angelica sinensis (A-SFE) was obtained by a stable extraction process and was chemically characterized by GC/MS. The anti-cancer effect of A-SFE when applied individually was explored in vitro through MTT, scratch, and Transwell assay. The effect of A-SFE on CRC cells under the influence of tumor-associated macrophages (TAMs) was explored by a co-culture model. The results showed that A-SFE could inhibit the viability, metastasis, and invasion of HCT116 cells, especially under the influence of TAMs. When 20–100 μg/ml of A-SFE and 8–64 μg/ml of OXA were used in combination in HCT116 cells, synergistic or additive effects were shown in different concentration combinations. The CT26 syngeneic mouse model was used to explore the anti-CRC effect of OXA combined with A-SFE in vivo. The tumor volume, expression levels of Ki67, MMP9, and CD206 in the OXA + A-SFE group were less than those in the OXA group. In conclusion, A-SFE has the potential to become an adjuvant drug for OXA in the treatment of CRC, which provides new strategies for anti-colorectal cancer research.

Alleviation of cisplatin-induced neuropathic pain, neuronal apoptosis, and systemic inflammation in mice by rapamycin

Platinum-based chemotherapeutic treatment of cancer patients is associated with debilitating adverse effects. Several adverse effects have been well investigated, and can be managed satisfactorily, but chemotherapy-induced peripheral neuropathy (CIPN) remains poorly treated. Our primary aim in this study was to investigate the neuroprotective effect of the immunomodulatory drug rapamycin in the mitigation of cisplatin-induced neurotoxicity. Pain assays were performed in vivo to determine whether rapamycin would prevent or significantly decrease cisplatin-induced neurotoxicity in adult male Balb/c mice. Neuropathic pain induced by both chronic and acute exposure to cisplatin was measured by hot plate assay, cold plate assay, tail-flick test, and plantar test. Rapamycin co-treatment resulted in significant reduction in cisplatin-induced nociceptive-like symptoms. To understand the underlying mechanisms behind rapamycin-mediated neuroprotection, we investigated its effect on certain inflammatory mediators implicated in the propagation of chemotherapy-induced neurotoxicity. Interestingly, cisplatin was found to significantly increase peripheral IL-17A expression and CD8- T cells, which were remarkably reversed by the pre-treatment of mice with rapamycin. In addition, rapamycin reduced the cisplatin-induced neuronal apoptosis marked by decreased neuronal caspase-3 activity. The rapamycin neuroprotective effect was also associated with reversal of the changes in protein expression of p21^Cip1, p53, and PUMA. Collectively, rapamycin alleviated some features of cisplatin-induced neurotoxicity in mice and can be further investigated for the treatment of cisplatin-induced peripheral neuropathy.

[6]-Shogaol Attenuates Oxaliplatin-Induced Allodynia through Serotonergic Receptors and GABA in the Spinal Cord in Mice

Although oxaliplatin is a well-known anti-cancer agent used for the treatment of colorectal cancer, treated patients often experience acute cold and mechanical allodynia as side effects. Unfortunately, no optimal treatment has been developed yet. In this study, [6]-shogaol (10 mg/kg, i.p.), which is one of the major bioactive components of Zingiber officinale roscoe (Z. officinale), significantly alleviated allodynia induced by oxaliplatin (6 mg/kg, i.p.) injection. Cold and mechanical allodynia were assessed by acetone drop and von Frey filament tests, respectively. The analgesic effect of [6]-shogaol was blocked by the intrathecal injection of 5-HT1A, 5-HT3, and GABAB receptor antagonists, NAN-190 (1 μg), MDL-72222 (15 μg), and CGP 55845 (10 μg), respectively. Furthermore, oxaliplatin injection lowered the GABA concentration in the superficial laminae of the spinal dorsal horn, whereas [6]-shogaol injection significantly elevated it. The GAD (glutamic acid decarboxylase) 65 concentration also increased after [6]-shogaol administration. However, pre-treatment of NAN-190 completely inhibited the increased GABA induced by [6]-shogaol in the spinal dorsal horn, whereas MDL-72222 partially blocked the effect. Altogether, these results suggest that [6]-shogaol could attenuate oxaliplatin-induced cold and mechanical allodynia through 5-HT_1A and 5-HT₃ receptor antagonists located in the GABAergic neurons in the spinal dorsal horn in mice.

Mechanisms of Chemotherapy-Induced Neurotoxicity

Since the first clinical trials conducted after World War II, chemotherapeutic drugs have been extensively used in the clinic as the main cancer treatment either alone or as an adjuvant therapy before and after surgery. Although the use of chemotherapeutic drugs improved the survival of cancer patients, these drugs are notorious for causing many severe side effects that significantly reduce the efficacy of anti-cancer treatment and patients’ quality of life. Many widely used chemotherapy drugs including platinum-based agents, taxanes, vinca alkaloids, proteasome inhibitors, and thalidomide analogs may cause direct and indirect neurotoxicity. In this review we discuss the main effects of chemotherapy on the peripheral and central nervous systems, including neuropathic pain, chemobrain, enteric neuropathy, as well as nausea and emesis. Understanding mechanisms involved in chemotherapy-induced neurotoxicity is crucial for the development of drugs that can protect the nervous system, reduce symptoms experienced by millions of patients, and improve the outcome of the treatment and patients’ quality of life.

Imbalanced Subthreshold Currents Following Sepsis and Chemotherapy: A Shared Mechanism Offering a New Therapeutic Target?

Both sepsis and treatment of cancer with chemotherapy are known to cause neurologic dysfunction. The primary defects seen in both groups of patients are neuropathy and encephalopathy; the underlying mechanisms are poorly understood. Analysis of preclinical models of these disparate conditions reveal similar defects in ion channel function contributing to peripheral neuropathy. The defects in ion channel function extend to the central nervous system where lower motoneurons are affected. In motoneurons the defect involves ion channels responsible for subthreshold currents that convert steady depolarization into repetitive firing. The inability to correctly translate depolarization into steady, repetitive firing has profound effects on motor function, and could be an important contributor to weakness and fatigue experienced by both groups of patients. The possibility that disruption of function, either instead of, or in addition to neurodegeneration, may underlie weakness and fatigue leads to a novel approach to therapy. Activation of serotonin (5HT) receptors in a rat model of sepsis restores the normal balance of subthreshold currents and normal motoneuron firing. If an imbalance of subthreshold currents also occurs in other central nervous system neurons, it could contribute to encephalopathy. We hypothesize that pharmacologically restoring the proper balance of subthreshold currents might provide effective therapy for both neuropathy and encephalopathy in patients recovering from sepsis or treatment with chemotherapy.

New diagnostic measures of oxaliplatin-induced peripheral sensory neuropathy

OBJECTIVE

Oxaliplatin-induced peripheral neuropathy (OIPN) is an unwanted side effect of oxaliplatin chemotherapy treatment. OIPN manifests in an acute phase that lasts a few days after injection and a persistent phase that may become chronic. Currently, there is no consensus about a clinically applicable, quantitative, and objective measure of OIPN.

METHODS

Seventeen patients treated with oxaliplatin containing adjuvant chemotherapy for stage III colon cancer, but otherwise healthy, were tested with six quantitative sensory tests (QST) and five large fibre perception threshold tracking (PTT) measures (quantified by, e.g., rheobase and electrotonus threshold) one hour before each of the 12 chemotherapy cycles given at two weeks' intervals. These measures were repeated at 3, 6, and 12-month follow-ups. The temporal development of OIPN assessed by the Common Terminology Criteria for Adverse Events (CTCAE) scale, QST, and PTT measures was calculated by linear regression.

RESULTS

The CTCAE score showed a tri-phasic increase during the treatment and remained increased during the follow-up. The vibration threshold (R = 0.25, p<0.001), the cold pain threshold (R = 0.17, p = 0.02), and the rheobase (R = 0.28, p < 0.001) increased during treatment, whereas the cold detection threshold (R=-0.16, p = 0.002) decreased. The cold pain threshold and the rheobase remained increased, and the cold detection and heat pain threshold remained decreased during follow-up.

CONCLUSIONS

Increased cold pain sensitivity and decreased large fibre sensitivity (increased rheobase) correlate to the persistent OIPN, whereas the CTCAE score assesses both acute and persistent OIPN. Furthermore, the novel PTT method assessed the nerve excitability changes caused by the oxaliplatin.

Severe Generalized Weakness, Paraplegia following administration of Oxaliplatin in a patient with refractory T-cell non-Hodgkin lymphoma: A case report

INTRODUCTION

Oxaliplatin is a third-generation platinum compound that used extensively for the treatment of various types of cancer especially gastrointestinal neoplasms. The main dose-limiting toxicities of oxaliplatin are hematological toxicity and peripheral sensory neuropathy.

CASE REPORT

A 42-year-old man with refractory peripheral T-cell lymphoma (PTCL) was admitted to receive GEMOX chemotherapy regimen (gemcitabine, oxaliplatin). Three days after receiving his third cycle of chemotherapy regimen, he was re-admitted to the emergency department with complaint of severe generalized weakness, and paraplegia in the lower extremities. According to clinical and para-clinical findings, chronic sensorimotor polyneuropathy with ongoing axonal loss was confirmed.

MANAGEMENT & OUTCOME

Intravenous dexamethasone 8 mg three times daily was started at the time of admission for the patient. Muscle weakness and sensory impairment improved dramatically within 10 days and the patient was able to walk with assistance.

DISCUSSION

Several cases of neuropathy following oxaliplatin and only one case with gemcitabine-based chemotherapy regimen have been previously reported. However, motor symptoms are rare unless in the setting of acute neuropathy due to oxaliplatin. The most striking finding of our study was the incidence of a chronic sensorimotor axonaldemyelinating polyneuropathy in a patient who were subjected to oxaliplatin therapy. In conclusion, we report a case of severe generalized weakness and paraplegia following administration of Oxaliplatin.

OUP accepted manuscript

In vitro models of the peripheral nervous system would benefit from further refinements to better support studies on neuropathies. In particular, the assessment of pain-related signals is still difficult in human cell cultures. Here, we harnessed induced pluripotent stem cells (iPSCs) to generate peripheral sensory neurons enriched in nociceptors. The objective was to generate a culture system with signaling endpoints suitable for pharmacological and toxicological studies. Neurons generated by conventional differentiation protocols expressed moderate levels of P2X3 purinergic receptors and only low levels of TRPV1 capsaicin receptors, when maturation time was kept to the upper practically useful limit of 6 weeks. As alternative approach, we generated cells with an inducible NGN1 transgene. Ectopic expression of this transcription factor during a defined time window of differentiation resulted in highly enriched nociceptor cultures, as determined by functional (P2X3 and TRPV1 receptors) and immunocytochemical phenotyping, complemented by extensive transcriptome profiling. Single cell recordings of Ca²⁺-indicator fluorescence from >9000 cells were used to establish the “fraction of reactive cells” in a stimulated population as experimental endpoint, that appeared robust, transparent and quantifiable. To provide an example of application to biomedical studies, functional consequences of prolonged exposure to the chemotherapeutic drug oxaliplatin were examined at non-cytotoxic concentrations. We found (i) neuronal (allodynia-like) hypersensitivity to otherwise non-activating mechanical stimulation that could be blocked by modulators of voltage-gated sodium channels; (ii) hyper-responsiveness to TRPV1 receptor stimulation. These findings and several other measured functional alterations indicate that the model is suitable for pharmacological and toxicological studies related to peripheral neuropathies.

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.

Targeting strategies for oxaliplatin-induced peripheral neuropathy: clinical syndrome, molecular basis, and drug development

Oxaliplatin (OHP)-induced peripheral neurotoxicity (OIPN) is a severe clinical problem and potentially permanent side effect of cancer treatment. For the management of OIPN, accurate diagnosis and understanding of significant risk factors including genetic vulnerability are essential to improve knowledge regarding the prevalence and incidence of OIPN as well as enhance strategies for the prevention and treatment of OIPN. The molecular mechanisms underlying OIPN are complex, with multi-targets and various cells causing neuropathy. Furthermore, mechanisms of OIPN can reinforce each other, and combination therapies may be required for effective management. However, despite intense investigation in preclinical and clinical studies, no preventive therapies have shown significant clinical efficacy, and the established treatment for painful OIPN is limited. Duloxetine is the only agent currently recommended by the American Society of Clinical Oncology. The present article summarizes the most recent advances in the field of studies on OIPN, the overview of the clinical syndrome, molecular basis, therapy development, and outlook of future drug candidates. Importantly, closer links between clinical pain management teams and oncology will advance the effectiveness of OIPN treatment, and the continued close collaboration between preclinical and clinical research will facilitate the development of novel prevention and treatments for OIPN.

JI017 Attenuates Oxaliplatin-Induced Cold Allodynia via Spinal TRPV1 and Astrocytes Inhibition in Mice

Oxaliplatin, a well-known chemotherapeutic agent, can induce severe neuropathic pain, which can seriously decrease the quality of life of patients. JI017 is an herb mixture composed of Aconitum carmichaelii, Angelica gigas, and Zingiber officinale. Its anti-tumor effect has been reported; however, the efficacy of JI017 against oxaliplatin-induced allodynia has never been explored. Single oxaliplatin injection [6 mg/kg, intraperitoneal, (i.p.)] induced both cold and mechanical allodynia, and oral administration of JI017 (500 mg/kg) alleviated cold but not mechanical allodynia in mice. Real-time polymerase chain reaction (PCR) analysis demonstrated that the upregulation of mRNA of spinal transient receptor potential vanilloid 1 (TRPV1) and astrocytes following oxaliplatin injection was downregulated after JI017 treatment. Moreover, TRPV1 expression and the activation of astrocytes were intensely increased in the superficial area of the spinal dorsal horn after oxaliplatin treatment, whereas JI017 suppressed both. The administration of TRPV1 antagonist [capsazepine, intrathecal (i.t.), 10 μg] attenuated the activation of astrocytes in the dorsal horn, demonstrating that the functions of spinal TRPV1 and astrocytes are closely related in oxaliplatin-induced neuropathic pain. Altogether, these results suggest that JI017 may be a potent candidate for the management of oxaliplatin-induced neuropathy as it decreases pain, spinal TRPV1, and astrocyte activation.

Involvement of Serotonergic System in Oxaliplatin-Induced Neuropathic Pain

Oxaliplatin is a chemotherapeutic agent widely used against colorectal and breast cancers; however, it can also induce peripheral neuropathy that can rapidly occur even after a single infusion in up to 80–90% of treated patients. Numerous efforts have been made to understand the underlying mechanism and find an effective therapeutic agent that could diminish pain without damaging its anti-tumor effect. However, its mechanism is not yet clearly understood. The serotonergic system, as part of the descending pain inhibitory system, has been reported to be involved in different types of pain. The malfunction of serotonin (5-hydroxytryptamine; 5-HT) or its receptors has been associated with the development and maintenance of pain. However, its role in oxaliplatin-induced neuropathy has not been clearly elucidated. In this review, 16 in vivo studies focused on the role of the serotonergic system in oxaliplatin-induced neuropathic pain were analyzed. Five studies analyzed the involvement of 5-HT, while fourteen studies observed the role of its receptors in oxaliplatin-induced allodynia. The results show that 5-HT is not involved in the development of oxaliplatin-induced allodynia, but increasing the activity of the 5-HT_1A, 5-HT_2A, and 5-HT₃ receptors and decreasing the action of 5-HT_2C and 5-HT₆ receptors may help inhibit pain.

Predictive Biomarkers of Oxaliplatin-Induced Peripheral Neurotoxicity

Oxaliplatin (OXA) is a platinum compound primarily used in the treatment of gastrointestinal cancer. OXA-induced peripheral neurotoxicity (OXAIPN) is the major non-hematological dose-limiting toxicity of OXA-based chemotherapy and includes acute transient neurotoxic effects that appear soon after OXA infusion, and chronic non-length dependent sensory neuronopathy symmetrically affecting both upper and lower limbs in a stocking-and-glove distribution. No effective strategy has been established to reverse or treat OXAIPN. Thus, it is necessary to early predict the occurrence of OXAIPN during treatment and possibly modify the OXA-based regimen in patients at high risk as an early diagnosis and intervention may slow down neuropathy progression. However, identifying which patients are more likely to develop OXAIPN is clinically challenging. Several objective and measurable early biomarkers for OXAIPN prediction have been described in recent years, becoming useful for informing clinical decisions about treatment. The purpose of this review is to critically review data on currently available or promising predictors of OXAIPN. Neurological monitoring, according to predictive factors for increased risk of OXAIPN, would allow clinicians to personalize treatment, by monitoring at-risk patients more closely and guide clinicians towards better counseling of patients about neurotoxicity effects of OXA.

Motor "freezing" with oxaliplatin

INTRODUCTION

We report the case of a patient who experienced severe neurological symptoms collectively characterized as being "frozen" following a second oxaliplatin infusion.

CASE REPORT

A 52-year-old woman with metastatic colon cancer developed severe motor slowing, delayed and incomplete grip and dorsiflexion, speech difficulty, visual impairment, leg cramping and tingling after her second infusion of oxaliplatin. She was transferred from the infusion center to the emergency room and admitted to the hospital for further evaluation. Motor, verbal, and ocular symptoms gradually resolved within 24 hours, and she was discharged home without sequela.Management and outcome: Oxaliplatin dose was subsequently lowered and infusion time increased, and she tolerated future treatments without motor, verbal, or ocular disturbance.

DISCUSSION

In this case report, we describe a rare form of neurological toxicity involving severe motor slowing, slurred speech, and blurry vision secondary to oxaliplatin.

Oxaliplatin-induced neuropathy occurs through impairment of haemoglobin proton buffering and is reversed by carbonic anhydrase inhibitors

Oxaliplatin is a cornerstone chemotherapeutic used in the treatment of colorectal cancer, the third leading cause of death in Western countries. Most side effects of this platinum-containing drug are adequately managed in the clinic, although acute and long-term neurotoxicity still severely compromises the quality of life of patients treated with oxaliplatin. We have previously demonstrated that therapeutically relevant concentrations/doses of oxaliplatin lead to a reduction in intracellular pH in mouse dorsal root ganglion (DRG) neurons in vitro and in vivo and that this alteration sensitizes TRPA1 and TRPV1 channels, which most likely mediate the allodynia associated with treatment. In this study, we show that oxaliplatin leads to a reduction of intracellular pH by forming adducts with neuronal haemoglobin, which acts in this setting as a proton buffer. Furthermore, we show that FDA-approved drugs that inhibit carbonic anhydrase (an enzyme that is linked to haemoglobin in intracellular pH homeostasis), ie, topiramate and acetazolamide, revert (1) oxaliplatin-induced cytosolic acidification and TRPA1 and TRPV1 modulation in DRG neurons in culture, (2) oxaliplatin-induced cytosolic acidification of DRG of treated animals, and (3) oxaliplatin-induced acute cold allodynia in mice while not affecting OHP-induced cytotoxicity on cancer cells. Our data would therefore suggest that reversal of oxaliplatin-induced cytosolic acidification is a viable strategy to minimize acute oxaliplatin-induced symptoms.

Therapeutic Agents for Oxaliplatin-Induced Peripheral Neuropathy; Experimental and Clinical Evidence

Oxaliplatin is an essential drug in the chemotherapy of colorectal, gastric, and pancreatic cancers, but it frequently causes peripheral neuropathy as a dose-limiting factor. So far, animal models of oxaliplatin-induced peripheral neuropathy have been established. The mechanisms of development of neuropathy induced by oxaliplatin have been elucidated, and many drugs and agents have been proven to have neuroprotective effects in basic studies. In addition, some of these drugs have been validated in clinical studies for their inhibitory effects on neuropathy. In this review, we summarize the basic and clinical evidence for the therapeutic effects of oxaliplatin. In basic research, there are many reports of neuropathy inhibitors that target oxidative stress, inflammatory response, sodium channel, transient receptor potential (TRP) channel, glutamate nervous system, and monoamine nervous system. Alternatively, very few drugs have clearly demonstrated the efficacy for oxaliplatin-induced peripheral neuropathy in clinical trials. It is important to activate translational research in order to translate basic research into clinical research.

Therapeutic Agents for Oxaliplatin-Induced Peripheral Neuropathy; Experimental and Clinical Evidence

Oxaliplatin is an essential drug in the chemotherapy of colorectal, gastric, and pancreatic cancers, but it frequently causes peripheral neuropathy as a dose-limiting factor. So far, animal models of oxaliplatin-induced peripheral neuropathy have been established. The mechanisms of development of neuropathy induced by oxaliplatin have been elucidated, and many drugs and agents have been proven to have neuroprotective effects in basic studies. In addition, some of these drugs have been validated in clinical studies for their inhibitory effects on neuropathy. In this review, we summarize the basic and clinical evidence for the therapeutic effects of oxaliplatin. In basic research, there are many reports of neuropathy inhibitors that target oxidative stress, inflammatory response, sodium channel, transient receptor potential (TRP) channel, glutamate nervous system, and monoamine nervous system. Alternatively, very few drugs have clearly demonstrated the efficacy for oxaliplatin-induced peripheral neuropathy in clinical trials. It is important to activate translational research in order to translate basic research into clinical research.

Therapeutic Agents for Oxaliplatin-Induced Peripheral Neuropathy; Experimental and Clinical Evidence

Oxaliplatin is an essential drug in the chemotherapy of colorectal, gastric, and pancreatic cancers, but it frequently causes peripheral neuropathy as a dose-limiting factor. So far, animal models of oxaliplatin-induced peripheral neuropathy have been established. The mechanisms of development of neuropathy induced by oxaliplatin have been elucidated, and many drugs and agents have been proven to have neuroprotective effects in basic studies. In addition, some of these drugs have been validated in clinical studies for their inhibitory effects on neuropathy. In this review, we summarize the basic and clinical evidence for the therapeutic effects of oxaliplatin. In basic research, there are many reports of neuropathy inhibitors that target oxidative stress, inflammatory response, sodium channel, transient receptor potential (TRP) channel, glutamate nervous system, and monoamine nervous system. Alternatively, very few drugs have clearly demonstrated the efficacy for oxaliplatin-induced peripheral neuropathy in clinical trials. It is important to activate translational research in order to translate basic research into clinical research.

Addressing the Need of a Translational Approach in Peripheral Neuropathy Research: Morphology Meets Function

Peripheral neuropathies (PNs) are a type of common disease that hampers the quality of life of affected people. Treatment, in most cases, is just symptomatic and often ineffective. To improve drug discovery in this field, preclinical evidence is warranted. In vivo rodent models allow a multiparametric approach to test new therapeutic strategies, since they can allow pathogenetic and morphological studies different from the clinical setting. However, human readouts are warranted to promptly translate data from the bench to the bedside. A feasible solution would be neurophysiology, performed similarly at both sides. We describe a simple protocol that reproduces the standard clinical protocol of a neurophysiology hospital department. We devised the optimal montage for sensory and motor recordings (neurography) in mice, and we also implemented F wave testing and a short electromyography (EMG) protocol at rest. We challenged this algorithm by comparing control animals (BALB/c mice) with a model of mild neuropathy to grasp even subtle changes. The neurophysiological results were confirmed with neuropathology. The treatment group showed all expected alterations. Moreover, the neurophysiology matched the neuropathological analyses. Therefore, our protocol can be suggested to promptly translate data from the bench to the bedside and vice versa.

Zingiber officinale Roscoe Rhizomes Attenuate Oxaliplatin-Induced Neuropathic Pain in Mice

Oxaliplatin is a platinum derivative chemotherapeutic drug widely used against cancers, but even a single treatment can induce a severe allodynia that requires treatment interruption and dose diminution. The rhizome of Zingiber officinale roscoe (Z. officinale, ginger), has been widely used in traditional medicine to treat various diseases causing pain; however, its effect against oxaliplatin-induced neuropathic pain has never been assessed. In mice, a single oxaliplatin (6 mg/kg, i.p.) treatment induced significant cold and mechanical allodynia. Cold and mechanical allodynia were assessed by acetone drop and von Frey filament tests, respectively. Water extracts of Z. officinale (100, 300, and 500 mg/kg, p.o.) significantly attenuated both cold and mechanical allodynia induced by oxaliplatin. Intrathecal pre-treatment with the antagonist 5-HT1A (NAN-190, i.t., 1 μg), but not with the antagonist 5-HT2A (ketanserin, i.t., 1 μg), significantly blocked the analgesic effect of Z. officinale against both cold and mechanical allodynia. However, 5-HT3 antagonist (MDL-72222, i.t., 15 μg) administration only blocked the anti-allodynic effect of Z. officinale against cold allodynia. Real-time PCR analysis demonstrated that Z. officinale significantly increased the mRNA expression of the spinal 5-HT1A receptor that was downregulated after oxaliplatin injection. These results suggest that Z. officinale may be a viable treatment option for oxaliplatin-induced neuropathic pain.

The hyperpolarization-activated cyclic nucleotide-gated channel currents contribute to oxaliplatin-induced hyperexcitability of DRG neurons

Humans are likely to experience mechanical allodynia and cold hyperalgesia after oxaliplatin intravenous injection. The mechanism by which oxaliplatin leads to these side effects is unknown. Since the hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are involved in the automatic depolarization of action potentials, we speculated that HCN channels are involved in oxaliplatin-induced hyperalgesia through action potentials. Our results showed that the density of HCN channel currents and the excitability of dorsal root ganglion neurons both increased after oxaliplatin perfusion at the cellular level. The neuronal hyperexcitability could be alleviated by ivabradine. Ivabradine inhibited oxaliplatin-induced mechanical allodynia and cold hyperalgesia at the individual rat level. Oxaliplatin enhanced the function of HCN channels, which in turn promoted the automatic depolarization of action potentials. The acceleration of automatic depolarization excited the neurons and caused more rapid firing of action potentials. Therefore, the HCN channel is a potential therapeutic target for the hyperalgesia induced by oxaliplatin.

Overview of Salvia miltiorrhiza as a Potential Therapeutic Agent for Various Diseases: An Update on Efficacy and Mechanisms of Action

Salvia miltiorrhiza Bunge (S. miltiorrhiza) is a medicinal herb that has been used for the treatment for various diseases such as cardiovascular and cerebrovascular diseases in East Asia including Korea. Considering its extensive usage as a therapeutic agent for multiple diseases, there is a need to review previous research regarding its therapeutic benefits and their mechanisms. Therefore, we searched PubMed and PubMed Central for articles reporting its therapeutic effects on certain disease groups including cancers, cardiovascular, liver, and nervous system diseases. This review provides an overview of therapeutic benefits and targets of S. miltiorrhiza, including inflammation, fibrosis, oxidative stress, and apoptosis. The findings on multi-functional properties of S. miltiorrhiza discussed in this article support the efficacy of S. miltiorrhiza extract on various diseases, but also call for further research on the multiple mechanisms that mediate its therapeutic effects.

Toxin-Induced Neuropathies

Peripheral neuropathies secondary to neurotoxicants are frequently considered but can be difficult to diagnose. Accurate diagnosis is important to avoid unnecessary testing, prevent further exposure, and initiate treatment when available. This article reviews key features of some of the more common or representative toxic neuropathies, including those caused by occupational and environmental exposure, medications, and chemotherapeutic agents.

Neurotoxicity of antineoplastic drugs: Mechanisms, susceptibility, and neuroprotective strategies

This review summarizes the adverse effects on the central and/or peripheral nervous systems that may occur in response to antineoplastic drugs. In particular, we describe the neurotoxic side effects of the most commonly used drugs, such as platinum compounds, doxorubicin, ifosfamide, 5-fluorouracil, vinca alkaloids, taxanes, methotrexate, bortezomib and thalidomide. Neurotoxicity may result from direct action of compounds on the nervous system or from metabolic alterations produced indirectly by these drugs, and either the central nervous system or the peripheral nervous system, or both, may be affected. The incidence and severity of neurotoxicity are principally related to the dose, to the duration of treatment, and to the dose intensity, though other factors, such as age, concurrent pathologies, and genetic predisposition may enhance the occurrence of side effects. To avoid or reduce the onset and severity of these neurotoxic effects, the use of neuroprotective compounds and/or strategies may be helpful, thereby enhancing the therapeutic effectiveness of antineoplastic drug.

Chronic defects in intraspinal mechanisms of spike encoding by spinal motoneurons following chemotherapy

Chemotherapy-induced sensorimotor disabilities, including gait and balance disorders, as well as physical fatigue often persist for months and sometimes years into disease free survival from cancer. While associated with impaired sensory function, chronic sensorimotor disorders might also depend on chemotherapy-induced defects in other neuron types. In this report, we extend consideration to motoneurons, which, if chronically impaired, would necessarily degrade movement behavior. The present study was undertaken to determine whether motoneurons qualify as candidate contributors to chronic sensorimotor disability independently from sensory impairment. We tested this possibility in vivo from rats 5 weeks following human-scaled treatment with one of the platinum-based compounds, oxaliplatin, widely used in chemotherapy for a variety of cancers. Action potential firing of spinal motoneurons responding to different fixed levels of electrode-current injection was measured in order to assess the neurons' intrinsic capacity for stimulus encoding. The encoding of stimulus duration and intensity corroborated in untreated control rats was severely degraded in oxaliplatin treated rats, in which motoneurons invariably exhibited erratic firing that was unsustained, unpredictable from one stimulus trial to the next, and unresponsive to changes in current strength. Direct measurements of interspike oscillations in membrane voltage combined with computer modeling pointed to aberrations in subthreshold conductances as a plausible contributor to impaired firing behavior. These findings authenticate impaired spike encoding as a candidate contributor to, in the case of motoneurons, deficits in mobility and fatigue. Aberrant firing also becomes a deficit worthy of testing in other CNS neurons as a potential contributor to perceptual and cognitive disorders induced by chemotherapy in patients.

Oral administration of Cystine and Theanine ameliorates oxaliplatin-induced chronic peripheral neuropathy in rodents

Oxaliplatin frequently causes severe peripheral neuropathy as a dose-limiting toxicity. However, this toxicity lacks a strategy for prevention. Cystine/Theanine is a supplement, which includes precursors for the biosynthesis of glutathione. In this study, we investigated the effects of Cystine/Theanine on oxaliplatin-induced peripheral neuropathy using an in vivo model. Repeated injection of oxaliplatin (4 mg/kg intraperitoneally twice a week for 2 weeks) caused mechanical allodynia, cold hyperalgesia and axonal degeneration of the sciatic nerve in rats. Mechanical allodynia and axonal degeneration, but not cold hyperalgesia, were ameliorated by daily co-administration of Cystine [200 mg/kg orally (p.o.)] and Theanine (80 mg/kg p.o.). Moreover, co-administration of Cystine and Theanine to rats significantly increased the glutathione level in the sciatic nerve compared with the oxaliplatin group. Furthermore, Cystine and Theanine did not attenuate the tumour cytotoxicity of oxaliplatin in C-26 tumour cell-bearing mice. These findings suggest that Cystine and Theanine may be beneficial for preventing oxaliplatin-induced peripheral neuropathy.

The Incidence of Oxaliplatin-Induced Peripheral Neurotoxicity at Khartoum Oncology Hospital: A Cross-Sectional Survey

Objective:

Using oxaliplatin-based chemotherapy in the treatment of cancer patients can cause a unique form of acute and chronic peripheral neurotoxicities. This study mainly aims to assess the incidence of oxaliplatin-induced peripheral neuropathy (OXAIPN).

Methods:

A cross-sectional study among 121 patients treated with oxaliplatin-based chemotherapy was conducted during the period of January to April 2019 at Khartoum Oncology Hospital. The incidence of acute neurotoxicity was assessed using a descriptive questionnaire for most common hyperexcitability and transient symptoms, while the incidence of chronic neurotoxicity was measured by the 20-item European Organization for Research and Treatment of Cancer Quality of Life Questionnaire for patients with chemotherapy-induced peripheral neuropathy and graded by the National Cancer Institute's Common Terminology Criteria for Adverse Events, Version 4.03.

Results:

Acute and chronic OXAIPN were found in 49.6% and 41.3% of patients, respectively. Most of the patients who developed acute OXAIPN symptoms manifested cold-induced pharyngolaryngeal dysesthesias (73.3%) or perioral paresthesias (71.7%). No significant association exists between the severity of chronic neurotoxicity and basic demographics. Most (79.1%) of the patients did not inform the doctors about their complaints, and 43.5% of those who informed doctors did not take any medication to manage OXAIPN.

Conclusions:

This study exhibits that oxaliplatin-based chemotherapy can cause symptoms of peripheral neurotoxicity in most of the patients with colorectal or gastric cancer in the form of acute neurotoxicity or chronic neurotoxicity.

Acute changes in nerve excitability following oxaliplatin treatment in mice

Oxaliplatin chemotherapy produces acute changes in peripheral nerve excitability in humans by modulating voltage-gated Na⁺ channel activity. However, there are few animal studies of oxaliplatin-induced neuropathy that demonstrate similar changes in excitability. In the present study, we measured the excitability of motor and sensory caudal nerve in C57BL/6 mice after oxaliplatin injections either systemically (intraperitoneal) or locally (intramuscular at the base of the tail). As opposed to intraperitoneal administration of oxaliplatin, a single intramuscular injection of oxaliplatin produced changes in both motor and sensory axons. In motor axons, oxaliplatin caused a greater change in response to long-lasting depolarization and an upward shift in the recovery cycle, particularly at 24 h [depolarizing threshold electrotonus (TEd) 10-20 ms, P = 0.0095; TEd 90-100 ms, P = 0.0056) and 48 h (TEd 10-20 ms, P = 0.02; TEd 90-100 ms, P = 0.04) posttreatment. Oxaliplatin treatment also stimulated the production of afterdischarges in motor axons. These changes were transient and showed dose dependence. Mathematical modeling demonstrated that these changes could be accounted for by slowing inactivation of voltage-gated Na⁺ channels by 73.3% and reducing fast K⁺ conductance by 47% in motor axons. In sensory axons, oxaliplatin caused an increase in threshold, a reduction in peak amplitude, and greater threshold changes to strong hyperpolarizing currents on days 4 and 8. Thus, local administration of oxaliplatin produced clinically relevant changes in nerve excitability in mice and may provide an alternative approach for the study of acute oxaliplatin-induced neurotoxicity.NEW & NOTEWORTHY We present a novel mouse model of acute oxaliplatin-induced peripheral neurotoxicity that is comparable to clinical observations. Intramuscular injection of oxaliplatin produced acute changes in motor nerve excitability that were attributable to alterations in Na⁺ and K⁺ channel activity. Conversely, we were unable to show any significant changes in nerve excitability with systemic intraperitoneal injections of oxaliplatin. This study suggests that local intramuscular injection is a valid approach for modelling oxaliplatin-induced peripheral neuropathy in animals.

Cisplatin-associated neuropathy characteristics compared with those associated with other neurotoxic chemotherapy agents (Alliance A151724)

PURPOSE

The current project was developed to obtain natural history information regarding cisplatin-induced peripheral neuropathy in males with testicular/germ cell cancers and to compare such neuropathy data with similarly obtained data in patients receiving other chemotherapy drugs in similarly conducted clinical trials.

METHODS

Patients without baseline neuropathy symptoms, who were initiating cisplatin-based chemotherapy, completed the EORTC CIPN 20 patient-reported instrument to evaluate chemotherapy-induced peripheral neuropathy (CIPN). Results were compared with EORTC CIPN 20 data obtained from independent study sets regarding patients receiving (1) paclitaxel, (2) combined paclitaxel and carboplatin, (3) oxaliplatin, or (4) a combination of doxorubicin and cyclophosphamide (AC). The last study set of patients on AC was selected to evaluate the use of EORTC CIPN 20 data in patients receiving chemotherapy not known to cause CIPN.

RESULTS

Cisplatin-induced neuropathy was more similar to neuropathy in patients receiving oxaliplatin than in those receiving paclitaxel. The cisplatin and oxaliplatin groups exhibited the coasting phenomenon and more prominent upper extremity symptoms than lower extremity symptoms during chemotherapy administration weeks. In contrast, paclitaxel-treated patients did not, on average, exhibit the coasting phenomenon; additionally, lower extremity symptoms were more prominent during the weeks when paclitaxel was administered. Cisplatin-induced neuropathy was less severe than was seen in patients in the other two groups, potentially because the cisplatin-receiving patients were younger. Patients receiving AC did not report substantial EORTC CIPN 20 changes.

CONCLUSION

Understanding neuropathy similarities and differences with various chemotherapy agents may help elucidate CIPN processes and facilitate means to prevent and/or treat established CIPN.

TRIAL REGISTRATION

NCT02677727.

Oxaliplatin-induced peripheral neuropathy: clinical features, mechanisms, prevention and treatment

Oxaliplatin (OXA) is a commonly used platinum-based chemotherapy drug for colorectal cancer. OXA-induced peripheral neurotoxcity (OIPN) is a comprehensive adverse reaction of OXA. OIPN can be divided into acute and chronic types according to clinical features and different mechanisms. The main clinical features of acute OIPN are cold-sensitive sensory symptoms and neuropathic pain in limbs. In addition to the above symptoms, chronic OIPN also produces autonomic nerve dysfunction. The most important mechanism involved in acute OIPN is the alteration of voltage-gated Na + channels, and nuclear DNA damage in chronic OIPN. There are some methods like reducing exposure to cold, calcium and magnesium salts, amifostine could be beneficial in acute OIPN prevention and dose modification, changing in schedule glutathione, duloxetine, selective serotonin reuptake inhibitors, carbonic anhydrase inhibitor in chronic OIPN prevention. Recent updates are provided in this article in relation to the clinical features, potential mechanisms, prevention and treatment of OIPN.

Long-term symptoms of polyneuropathy in breast and colorectal cancer patients treated with and without adjuvant chemotherapy

Background

The aim of this study was to assess chemotherapy‐induced polyneuropathy (CIPN) 5 years after adjuvant chemotherapy in patients with breast and colorectal cancer. The association of CIPN with quality of life, anxiety, and depression was analyzed.

Methods

Of a set of 100 patients with breast cancer and of 74 with colorectal cancer who had undergone surgery and adjuvant chemotherapy in 2011‐2012, 80 and 52 patients alive, respectively, were included together with two reference groups of 249 breast cancer patients and 83 colorectal cancer patients who had undergone surgery only. All patients were sent a questionnaire on alcohol consumption, smoking habits, comorbidity, medicine consumption, and oxaliplatin‐specific questions, as well as the Michigan Neuropathy Screening Instrument questionnaire (MNSIq), the Douleur Neuropathique 4 Questions (DN4q), the EQ‐5D, and the Hospital Anxiety and Depression Scale. Possible polyneuropathy was defined as the presence of numbness and/or tingling in the feet, secondly as a score of ≥4 on the MNSIq. Possible painful polyneuropathy was defined as pain in both feet and a score ≥3 on the DN4q.

Results

The prevalence of possible polyneuropathy defined by numbness and/or tingling in the feet was 38.8% (28.1‐50.3) after adjuvant docetaxel and 57.7% (43.2‐71.3) after adjuvant oxaliplatin, with no significant difference from a previous 1‐year follow‐up (P >.35). Fewer had possible polyneuropathy as defined by the MNSIq. Patients with possible polyneuropathy after adjuvant chemotherapy reported significantly lower quality of life than patients treated with surgery only.

Conclusion

Symptoms of polyneuropathy following adjuvant docetaxel and oxaliplatin persist 5 years after treatment and affect quality of life negatively.

Study on efficacy and safety of Huangqi Guizhi Wuwu decoction treatment for oxaliplatin induced peripheral neurotoxicity: A protocol for a randomized, controlled, double-blind, multicenter trial

BACKGROUND

Oxaliplatin can cause severe peripheral neurotoxicity, which is an important reason for clinical oxaliplatin reduction and cessation of treatment. Oxaliplatin induced peripheral neurotoxicity (OIPN) can cause paresthesia and dysesthesia, even affect the quality life of patients. So far, there are no recognized and effective measures to prevent OIPN. Huangqi Guizhi Wuwu decoction is a classical prescription of ancient Chinese medicine recorded in "the synopsis of the Golden Chamber," which can be used in the treatment of various neurotoxicity. However, there is a lack of large-scale and high-quality clinical studies on the prevention of OIPN by Huangqi Guizhi Wuwu decoction. The purpose of this study is to evaluate the efficacy and safety of Huangqi Guizhi Wuwu decoction on preventing OIPN.

METHODS/DESIGN

This study is a randomized, controlled, double-blind, and multicenter clinical trial. Three hundred sixty patients will be randomly assigned into Huangqi Guizhi Wuwu decoction group and Huangqi Guizhi Wuwu decoction mimetic agent group. Patients will receive chemotherapy with FOLFOX of 8 cycles of 3 weeks with Traditional Chinese Medicine (TCM) for 6 months and 1-year follow-up. The primary outcome measure is the differences in the incidence of chronic neurotoxicity of grade 2 and above during and after treatment. The secondary outcome measure is the improvement in other symptoms associated with chemotherapy. Four methods will be used to evaluate the efficacy of neurotoxicity, including oxaliplatin specific toxicity grading standard (Levi classification); CTCAE4.02 version; EORTC QLQ-CIPN20 scale, EORTC QLQ C30 scale, and EORTC QLQ-CR29 scale are used at the same time; Electromyography.

DISCUSSION

This study will provide objective evidences to evaluate the efficacy and safety of Huangqi Guizhi Wuwu Decoction on preventing OIPN.

TRIAL REGISTRATION

Clinical Trials.gov (Identifier: NCT04261920).

ZeOxaNMulti Trial: A Randomized, Double-Blinded, Placebo-Controlled Trial of Oral PMA-zeolite to prevent Chemotherapy-Induced Side Effects, in particular, Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is the most frequently reported adverse effect of oxaliplatin. In this study, we set out to evaluate the role of the panaceo-micro-activation (PMA) zeolite in the reduction of the incidence of CIPN and hematological and liver toxicity. The possible impact of the PMA-zeolite as an adjuvant therapeutic agent is based on its detoxification properties toward agents promoting the development of neuropathy (e.g., ammonium—recognized as a neurotoxic agent produced by tumors), as well as its positive impact on immunity and oxidative stress through its effects in the gastrointestinal tract. From April 2015 to October 2018, a total of 120 patients (pts) diagnosed with predominantly colorectal cancer requiring oxaliplatin-based chemotherapy were randomized to receive either the PMA-zeolite (Multizeo Med) or placebo while undergoing oxaliplatin-based chemotherapy. A nerve-conduction study (NCS) was planned at the baseline, after three and six months of chemotherapy, to evaluate CIPN. Furthermore, the evaluation of hematological and liver toxicity was performed during every cycle of chemotherapy. 70.6% and 64.3% of patients developed CIPN in the placebo and the PMA-zeolite group, respectively. Patients treated with the PMA-zeolite were able to undergo more cycles of chemotherapy (p = 0.03), which also indicates a significant improvement in tolerance to the therapy. The group treated with the PMA-zeolite showed a lower CIPN (although not statistically significant within the whole group of subjects) compared to patients receiving placebo. This advantage was, however, statistically significant in men (p = 0.047). In addition, supplementation with the PMA-zeolite resulted in a lower incidence of severe-grade hematological toxicity (trend toward statistical significance of p = 0.09 was observed). Cancer patients may benefit from the therapy with the appropriate certified zeolite-products (e.g., the PMA-zeolite) for human use in CIPN. The lower CIPN (statistically significant results in the male subgroup) was accompanied by a trend of lower incidence of severe-grade hematological toxicity. Furthermore, these benefits led to a better tolerance toward chemotherapy (increase in cycles) and allow an improved compliance with the oncological treatment protocol.

Neuroprotective effect of alogliptin on oxaliplatin-induced peripheral neuropathy in vivo and in vitro

Oxaliplatin is a platinum-based antineoplastic drug commonly used for treating colorectal, gastric, and pancreatic cancer. However, it frequently causes peripheral neuropathy as dose-limiting toxicity and is lacking a strategy for prevention. Alogliptin, a dipeptidyl peptidase 4 (DPP-4) inhibitor, is an oral antidiabetic drug. Previous studies have shown that DPP-4 inhibitors have pleiotropic effects, including neuroprotection. In this study, we investigated the effects of alogliptin on oxaliplatin-induced peripheral neuropathy using in vitro and in vivo models. In PC12 cells, alogliptin attenuated neurite disorders induced by oxaliplatin and cisplatin. The repeated injection of oxaliplatin caused mechanical allodynia and axonal degeneration of the sciatic nerve in rats. These neuropathies were ameliorated by co-administration of alogliptin. Moreover, alogliptin did not attenuate tumor cytotoxicity of oxaliplatin in the cultured colon, gastric, or pancreatic cancer cell lines and tumor-bearing mice. These findings suggest that alogliptin may be beneficial for preventing oxaliplatin-induced peripheral neuropathy.

Protective effect of N-acetylcysteine on oxaliplatin-induced neurotoxicity in patients with colorectal and gastric cancers: A randomized, double blind, placebo-controlled, clinical trial

PURPOSE

Neuropathy is one of the most prevalent and dose-limiting side effects of platinum chemotherapeutic agents. N-acetylcysteine is an antioxidant thiol which is able to increase whole blood concentration of glutathione, which may be protective against chemotherapy-induced neuropathy. The aim of this study was to evaluate the effect of N-acetylcysteine on neurotoxicity induced by oxaliplatin in patients with gastric or colorectal cancers.

METHODS

During this randomized, double-blinded, placebo-controlled clinical trial, the preventive effect of N-acetylcysteine effervescent tablets was assessed in comparison with placebo, on neuropathy occurrence. Thirty-two patients with colorectal or gastric cancer randomly received N-acetylcysteine (two 600 mg tablets) or placebo tablets 1 h before receiving oxaliplatin in dose in XELOX (oxaliplatin and capecitabine regimen) for eight courses of chemotherapy. Neuropathy severity was assessed after eight courses of chemotherapy based on National Cancer Institute Common Terminology for Adverse Events (NCI-CTCAE) criteria neuropathy grading scale and also sensory and motor electrophysiological assessment was performed by a neurologist.

RESULTS

The NCI-CTCAE scale grade of patients in intervention group was significantly lower than placebo group after eight course of oxaliplatin (P = 0.01); however, the sensory electrophysiological assessment result was not significantly different (P = 0.501). No patient in both group had motor electrophysiological changes.

CONCLUSION

The results of this study showed that N-acetylcysteine could reduce the incidence of the neuropathy induced by oxaliplatin and delay its occurrence in patients with gastric or colorectal cancers.

Chemotherapy-induced peripheral neuropathy-part 2: focus on the prevention of oxaliplatin-induced neurotoxicity

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is regarded as one of the most common dose-limiting adverse effects of several chemotherapeutic agents, such as platinum derivatives (oxaliplatin and cisplatin), taxanes, vinca alkaloids and bortezomib. CIPN affects more than 60% of patients receiving anticancer therapy and although it is a nonfatal condition, it significantly worsens patients' quality of life. The number of analgesic drugs used to relieve pain symptoms in CIPN is very limited and their efficacy in CIPN is significantly lower than that observed in other neuropathic pain types. Importantly, there are currently no recommended options for effective prevention of CIPN, and strong evidence for the utility and clinical efficacy of some previously tested preventive therapies is still limited.

METHODS

The present article is the second one in the two-part series of review articles focused on CIPN. It summarizes the most recent advances in the field of studies on CIPN caused by oxaliplatin, the third-generation platinum-based antitumor drug used to treat colorectal cancer. Pharmacological properties of oxaliplatin, genetic, molecular and clinical features of oxaliplatin-induced neuropathy are discussed.

RESULTS

Available therapies, as well as results from clinical trials assessing drug candidates for the prevention of oxaliplatin-induced neuropathy are summarized.

CONCLUSION

Emerging novel chemical structures-potential future preventative pharmacotherapies for CIPN caused by oxaliplatin are reported.

The Relationship Between Evaluation Methods for Chemotherapy-Induced Peripheral Neuropathy

Numbness and pain are currently evaluated using subjective methods such as the visual analogue scale (VAS). PainVision (PV) is an analytical instrument that was designed to quantitatively assess sense perception and nociception in patients. Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most important adverse events that renders prolonged chemotherapy difficult. To assess the features of CIPN, we aimed to compare PV methods with existing methods. A total of 73 patients received oxaliplatin for metastatic colorectal cancer. Registered patients included 37 men and 36 women in the range of 37 to 89 years (median 70). CIPN was evaluated a total of 483 times (median per patient six times). Our study examined the correlation between evaluation methods of CIPN using VAS and PV, respectively. The average VAS (hand), VAS (foot) and PV scores of CIPN were 18.4 (range: 0–100), 23.8 (range: 0–100), and 24.7 (range: 0–496), respectively. VAS (hand), VAS (foot), and FACT/GOG-NTX (NTX2, NTX4 and NTX8) were significantly correlated with PV. PV showed no correlation with a Disk-Criminator or the monofilament test used as a quantitative evaluation. The evaluation of CIPN is complex, and further improvement is required for evaluation with PV.

Overview of cisplatin-induced neurotoxicity and ototoxicity, and the protective agents

Cisplatin has dramatically improved the survival rate of cancer patients, but it has also increased the prevalence of hearing and neurological deficits in this population. Cisplatin induces ototoxicity, peripheral (most prevalent) and central (rare) neurotoxicity. This review addresses the ototoxicity and the neurotoxicity associated with cisplatin-based chemotherapy, providing an integrated view of the potential protective agents that have been evaluated in vitro, in vivo and in clinical trials, their targets and mechanisms of protection and their effects on the antitumor activity of cisplatin. So far, the findings are insufficient to support the use of any oto- or neuroprotective agent before, during or after cisplatin chemotherapy. Despite their promising effects in vitro and in animal studies, many agents have not been evaluated in clinical trials. Additionally, the clinical trials have limitations concerning the sample size, controls, measurement, heterogeneous groups, several arms of treatment, short follow-up or no blinding. Besides that, for most agents, the effects on the antitumor activity of cisplatin have not been evaluated in tumor-bearing animals, which discourages clinical trials. Further well-designed randomized controlled clinical trials are necessary to definitely demonstrate the effectiveness of the oto- or neuroprotective agents proposed by animal and in vitro studies.

Pathogenesis of platinum-induced peripheral neurotoxicity: Insights from preclinical studies

One of the most relevant dose-limiting adverse effects of platinum drugs is the development of a sensory peripheral neuropathy that highly impairs the patients' quality of life. Nowadays there are no available efficacy strategies for the treatment of platinum-induced peripheral neurotoxicity (PIPN), and the only way to prevent its development and progression is by reducing the dose of the cytostatic drug or even withdrawing the chemotherapy regimen. This clinical issue has been the main focus of hundreds of preclinical research works during recent decades. As a consequence, dozens of in vitro and in vivo models of PIPN have been developed to elucidate the molecular mechanisms involved in its development and to find neuroprotective targets. The apoptosis of peripheral neurons has been identified as the main mechanism involved in PIPN pathogenesis. This mechanism of DRG sensory neurons cell death is triggered by the nuclear and mitochondrial DNA platination together with the increase of the oxidative cellular status induced by the depletion of cytoplasmic antioxidant mechanisms. However, since there has been no successful transfer of preclinical results to clinical practise in terms of therapeutic approaches, some mechanisms of PIPN pathogenesis still remain to be elucidated. This review is focused on the pathogenic mechanisms underlying PIPN described up to now, provided by the critical analysis of in vitro and in vivo models.

Topiramate prevents oxaliplatin-related axonal hyperexcitability and oxaliplatin induced peripheral neurotoxicity

Oxaliplatin (OHP) Induced Peripheral Neurotoxicity (OIPN) is one of the dose-limiting toxicities of the drug and these adverse effects limit cancer therapy with L-OHP, used for colorectal cancer treatment. Acute neurotoxicity consists of symptoms that are the hallmarks of a transient axonal hyperexcitability; chronic neurotoxicity has a clinical picture compatible with a length-dependent sensory neuropathy. Acute OIPN pathogenesis has been linked to sodium voltage-operated channels (Na + VOC) dysfunction and it has been advocated as a possible predisposing factor to chronic neurotoxicity. We tested if topiramate (TPM), a well-known Na + VOC modulator, was able to modify acute as well as chronic OIPN. The project was divided into two parts. In Experiment 1 we tested by means of Nerve Excitability Testing (NET) a cohort of female Wistar rats to assess TPM effects after a single OHP administration (5 mg/kg, iv). In Experiment 2 we assessed TPM effects after chronic OHP treatment (5 mg/kg, 2qw4ws, iv) using NET, nerve conduction studies (NCS), behavioral tests and neuropathology (caudal nerve morphometry and morphology and Intraepidermal Nerve Fiber [IENF] density). In Experiment 1 TPM was able to prevent OHP effects on Na + VOC: OHP treatment induced a highly significant reduction of the sensory nerve's threshold, during the superexcitability period (p-value = 0.008), whereas TPM co-administration prevented this effect. In Experiment 2 we verified that TPM was able to prevent not only acute phenomena, but also to completely prevent chronic OIPN. This latter observation was supported by a multimodal approach: in fact, only OHP group showed altered findings compared to CTRL group at a neurophysiological (proximal caudal nerve sensory nerve action potential [SNAP] amplitude, p-value = 0.001; distal caudal nerve SNAP amplitude, p-value<0.001, distal caudal nerve sensory conduction velocity, p-value = 0.04), behavioral (mechanical threshold, p-value 0.003) and neuropathological levels (caudal nerve fibers density, p-value 0.001; IENF density, p-value <0.001). Our data show that TPM is a promising drug to prevent both acute and chronic OIPN. These findings have a high translational potential, since they were obtained using outcome measures that match clinical practice and TPM is already approved for clinical use being free from detrimental interaction with OHP anticancer properties.

Ethosuximide improves chronic pain-induced anxiety- and depression-like behaviors

Chronic pain is a heavy burden disease. Current treatments are generally weakly effective or associated with adverse effects. New therapeutic approaches are therefore needed. Recent studies have suggested T-type calcium channels as an attractive target for the treatment of chronic pain. In this perspective, it was decided to perform a preclinical evaluation of the efficacy of ethosuximide, a T-type channel blocker used clinically as an antiepileptic, as a novel pharmacological treatment for chronic pain. Assessment of the effect of ethosuximide was thus made in both nociception and pain-related comorbidities as anxiety and depression are frequently encountered in chronic pain patients. Our results show that such symptoms occurred in three animal models of chronic pain designed to reflect traumatic neuropathic, chemotherapy-induced neuropathic and inflammatory pain conditions. Administration of ethosuximide reduced both chronic pain and comorbidities with a marked intensity ranging from partial reduction to a complete suppression of symptoms. These results make ethosuximide, and more broadly the inhibition of T-type calcium channels, a new strategy for the management of uncontrolled chronic pain, likely to improve not only pain but also the accompanying anxiety and depression.

Upregulation of ERK phosphorylation in rat dorsal root ganglion neurons contributes to oxaliplatin-induced chronic neuropathic pain

Oxaliplatin is the first-line chemotherapy for metastatic colorectal cancer. Unlike other platinum anticancer agents, oxaliplatin does not result in significant renal impairment and ototoxicity. Oxaliplatin, however, has been associated with acute and chronic peripheral neuropathies. Despite the awareness of these side-effects, the underlying mechanisms are yet to be clearly established. Therefore, in this study, we aimed to understand the factors involved in the generation of chronic neuropathy elicited by oxaliplatin treatment. We established a rat model of oxaliplatin-induced neuropathic pain (4 mg kg^-1 intraperitoneally). The paw withdrawal thresholds were assessed at different time-points after the treatment, and a significant decrease was observed 3 and 4 weeks after oxaliplatin treatment as compared to the vehicle treatment (4.4 ± 1.0 vs. 16.0 ± 4.1 g; P < 0.05 and 4.4 ± 0.7 vs. 14.8 ± 3.1 g; P < 0.05, respectively). We further evaluated the role of different mitogen-activated protein kinases (MAPKs) pathways in the pathophysiology of neuropathic pain. Although the levels of total extracellular signal-regulated kinase (ERK) 1/2 in the dorsal root ganglia (DRG) were not different between oxaliplatin and vehicle treatment groups, phosphorylated ERK (p-ERK) 1/2 was up-regulated up to 4.5-fold in the oxaliplatin group. Administration of ERK inhibitor PD98059 (6 μg day^-1 intrathecally) inhibited oxaliplatin-induced ERK phosphorylation and neuropathic pain. Therefore, upregulation of p-ERK by oxaliplatin in rat DRG and inhibition of mechanical allodynia by an ERK inhibitor in the present study may provide a better understanding of intracellular molecular alterations associated with oxaliplatin-induced neuropathic pain and help in the development of potential therapeutics.

Phase III randomized, placebo-controlled, double-blind study of monosialotetrahexosylganglioside for the prevention of oxaliplatin-induced peripheral neurotoxicity in stage II/III colorectal cancer

Background

Monosialotetrahexosylganglioside (GM1) is a neuroprotective glycosphingolipid that repairs nerves. Oxaliplatin‐based chemotherapy is neurotoxic. This study assessed the efficacy of GM1 for preventing oxaliplatin‐induced peripheral neurotoxicity (OIPN) in colorectal cancer (CRC) patients receiving oxaliplatin‐based chemotherapy.

Methods

In total, 196 patients with stage II/III CRC undergoing adjuvant chemotherapy with mFOLFOX6 were randomly assigned to intravenous GM1 or a placebo. The primary endpoint was the rate of grade 2 or worse cumulative neurotoxicity (NCI‐CTCAE). The secondary endpoints were chronic cumulative neurotoxicity (EORTCQLQ‐CIPN20), time to grade 2 neurotoxicity (NCI‐CTCAE or the oxaliplatin‐specific neuropathy scale), acute neurotoxicity (analog scale), rates of dose reduction or withdrawal due to OIPN, 3‐year disease‐free survival (DFS) and adverse events.

Results

There were no significant differences between the arms in the rate of NCI‐CTCAE grade 2 or worse neurotoxicity (GM1: 33.7% vs placebo: 31.6%; P = .76) or neuropathy measured by the EORTCQLQ‐CIPN20 or time to grade 2 neurotoxicity using NCI‐CTCAE and the oxaliplatin‐specific neuropathy scale. GM1 substantially decreased participant‐reported acute neurotoxicity (sensitivity to cold items [P < .01], discomfort swallowing cold liquids [P < .01], throat discomfort [P < .01], muscle cramps [P < .01]). The rates of dose reduction or withdrawal were not significantly different between the arms (P = .08). The 3‐year DFS rates were 85% and 83% in the GM1 and placebo arms, respectively (P = .19). There were no differences in toxicity between the arms.

Conclusion

Patients receiving GM1 were less troubled by the symptoms of acute neuropathy. However, we do not support the use of GM1 to prevent cumulative neurotoxicity. (http://ClinicalTrials.gov number, NCT02251977).

Skin platinum deposition in colorectal cancer patients following oxaliplatin-based therapy

BACKGROUND

Oxaliplatin is widely used in the treatment of gastrointestinal malignancies. One of the most common and dose-limiting side effects of oxaliplatin is the chronic peripheral sensory neuropathy. The mechanism of this neurotoxicity is poorly understood and there are no effective preventive or treatment strategies, other than oxaliplatin dose interruption or reduction.

METHODS

Colorectal cancer patients who completed FOLFOX at least 6 months prior to enrollment were eligible. EORTC QLQ-CIPN20 questionnaire was used for assessing self-reported neuropathic symptom. Blood samples and skin biopsies were obtained and analyzed for platinum.

RESULTS

Twelve patients were enrolled. The mean cumulative dose of oxaliplatin was 818 ± 54 mg/m², and the median time from last dose of oxaliplatin was 38.7 months (range: 7.2-65.6 months). The QLQ-CIPN20 sensory score was 18 or less in 10 patients and 19 and 25, respectively, in 2 patients. Platinum was detectable in plasma from 4/12 patients up to 63.3 months after the completion of FOLFOX. In all six patients with skin biopsies, platinum was present in the skin with imaging mass cytometry.

CONCLUSIONS

QLQ-CIPN20 scores and plasma platinum concentrations were not related to cumulative doses of oxaliplatin or interval from the last dose of oxaliplatin. Platinum was readily detectable in skin biopsies more than 60 months post-completion of FOLFOX. This is the first demonstration of platinum deposition in skin post-oxaliplatin treatment and it provides a possible mechanism for oxaliplatin-induced peripheral sensory neuropathy and its persistence.

Are Ergothioneine Levels in Blood Associated with Chronic Peripheral Neuropathy in Colorectal Cancer Patients Who Underwent Chemotherapy?

Objective: Chronic Chemotherapy-Induced Peripheral Neuropathy (CIPN) is highly prevalent among colorectal cancer (CRC) patients. Ergothioneine (ET) - a dietary antioxidant -protected against CIPN in experimental models, but human studies are lacking. We explored whether whole blood ET levels were associated with chronic peripheral neuropathy among CRC patients who had completed chemotherapy.Methods: At diagnosis, median ET-concentration in whole blood of 159 CRC patients was 10.2 μg/ml (7.2-15.8). Patients completed questionnaires on peripheral neuropathy 6 months after completion of chemotherapy. We calculated prevalence ratios (PR) to assess associations of ET-concentrations and prevalence of peripheral neuropathy and used linear regression to assess associations with severity of peripheral neuropathy.Results: Prevalence of total and sensory peripheral neuropathy were both 81%. Higher ET-concentrations tended to be associated with lower prevalence of total and sensory peripheral neuropathy, but not statistically significant (highest versus lowest tertile of ET: PR = 0.93(0.78, 1.11) for total neuropathy, and PR = 0.84(0.70, 1.02) for sensory neuropathy). ET-concentrations were not associated with severity of neuropathy.Conclusion: Statistically significant associations were not observed, possibly because of limited sample size. Although data may putatively suggest higher levels of ET to be associated with a lower prevalence of neuropathy, analyses should be repeated in larger populations with larger variability in ET-concentrations.