Long-term course of oxaliplatin-induced polyneuropathy: a prospective 2-year follow-up study

Plasma neurofilament light chain levels in chemotherapy-induced peripheral neurotoxicity according to type of anticancer drug

BACKGROUND AND PURPOSE

A real-time biomarker in chemotherapy-induced peripheral neurotoxicity (CIPN) would be useful for clinical decision-making during treatment. Neurofilament light chain (NfL) can be detected in blood in the case of neuroaxonal damage. The aim of the study was to compare the levels of plasma NfL (pNfL) according to the type of chemotherapeutic agent and the severity of CIPN.

METHODS

This single-center prospective observational longitudinal study included patients treated with paclitaxel (TX; n = 34), brentuximab vedotin (BV; n = 29), or oxaliplatin (PT; n = 19). All patients were assessed using the Total Neuropathy Score-clinical version and Common Terminology Criteria for Adverse Events before, during, and up to 6-12 months after the end of treatment. Nerve conduction studies (NCS) were performed before and after chemotherapy discontinuation. Consecutive plasma samples were analyzed for NfL levels using a Simoa® analyzer. Changes in pNfL were compared between groups and were eventually correlated with clinical and NCS data. Clinically relevant (CR) CIPN was considered to be grade ≥ 2.

RESULTS

Eighty-two patients, mostly women (59.8%), were included. One third of the patients who received TX (29.4%), BV (31%), or PT (36.8%) developed CR-CIPN, respectively, without differences among them (p = 0.854). Although pNfL significantly increased during treatment and decreased throughout the recovery period in all three groups, patients receiving TX showed significantly greater and earlier changes in pNfL levels compared to the other agents (p < 0.001).

CONCLUSIONS

A variable change in pNfL is observed depending on the type of agent and mechanism of neurotoxicity with comparable CIPN severity, strongly implying the need to identify different cutoff values for each agent.

Efficacy and safety of traditional plant-based medicines for preventing chronic oxaliplatin-induced peripheral neurotoxicity in patients with colorectal cancer: A systematic review and meta-analysis with core herb contribution

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional plant-based medicines (TMs) have been widely used to prevent chronic oxaliplatin-induced peripheral neurotoxicity (OIPN). However, the prevention and safety of TMs for chronic OIPN remain ambiguous. Furthermore, diverse TM prescriptions and complicated components limit in-depth research on the mechanisms of TMs.

AIM OF THIS STUDY

To determine core TMs and potential pharmacological pathways on the basis of a thorough investigation into the preventive benefits and safety of oral TMs for chronic OIPN in colorectal cancer (CRC).

METHODS

A search of the PubMed, Cochrane, Embase, CNKI, VIP, and Wanfang databases for RCTs reporting on TMs for chronic OIPN was conducted through December 1, 2022. Subgroup analysis, sensitivity analysis and meta-regression were applied to assess the impacts of influencing variables. The assessment of Risk of Bias was relied on Cochrane Risk of Bias tool. The funnel plot, Egger's test, and the Trim and Fill method were applied to identify potential publication bias. Trial sequential analyses (TSA) were carried out by the TSA tool to increase the robustness. The assessment of the quality of evidence was according to the GRADE system. System pharmacology analysis was employed to screen core herbal combinations to elucidate possible mechanisms for preventing chronic OIPN in CRC.

RESULTS

The pooled effect estimate with robustness increased by TSA analysis demonstrated that oral TMs appeared to significantly decrease the incidence of chronic OIPN (RR = 0.66, 95% CI (0.56, 0.78); P＜0.00001), leukocytopenia (RR = 0.65, 95% CI (0.54,0.79); P＜0.00001), and nausea and vomiting (RR = 0.72, 95% CI (0.61,0.84); P＜0.0001) as well as improve the Objective Response Rate (ORR) (RR = 1.31, 95% CI (1.09,1.56); P = 0.003). The incidence of severe chronic OIPN was revealed a significant reduction, particularly when chemotherapy was administered for periods of time shorter than six months (RR = 0.33, 95% CI (0.15,0.71); P = 0.005; actuation duration＜3 months; RR = 0.33, 95% CI (0.17,0.62); P = 0.0007; actuation duration≥3 months, ＜6 months). The considerable heterogeneity among studies may be attributable to the severity of dysfunction categorized by grade and accumulated dosage. Using core TMs consisting of Astragalus membranaceus (Fisch.) Bunge, Atractylodes Macrocephala Koidz., Poria cocos (Schw.) Wolf, and Codonopsis pilosula (Franch.) Nannf. To regulate nuclear factor-kappa B against inflammation caused by activation of microglia might be an approach to preventing chronic OIPN.

CONCLUSIONS

TMs appear to be effective and safe in the prevention of chronic OIPN, especially severe chronic OIPN. Additionally, core TMs consisting of Astragalus membranaceus (Fisch.) Bunge, Atractylodes Macrocephala Koidz., Poria cocos (Schw.) Wolf, and Codonopsis pilosula (Franch.) Nannf were presumably responsible for reducing the incidence of chronic OIPN, and the mechanism may be related to relieving inflammation. However, quality-assured trials with long-term follow-up for exploring inflammatory factors and preliminary research on core TMs and pharmacological pathways are needed.

Incidence and risk factors for developing chemotherapy-induced neuropathic pain in 500 cancer patients: A file-based observational study

OBJECTIVE

To define the incidence and risk factors for developing chemotherapy-induced neuropathic pain (CINP).

METHODS

Retrospective, file-based analysis on cancer patients who received any type of conventional chemotherapy and for whom neurological evaluation was asked to reveal the extent of chemotherapy-induced peripheral neurotoxicity (CIPN) with or without CINP. CINP was assessed by means of the PI-NRS and Douleur Neuropathique-4 questionnaire. The total neuropathy score-clinical version graded the severity of CIPN.

RESULTS

The medical files of 500 chemotherapy-treated cancer patients were reviewed. Any grade chronic CIPN was disclosed in 343 (68.6%) patients and CINP in 127 (37%) of them, corresponding to an overall percentage of 25.4% among all 500 included patients. The logistic regression analysis identified as independent predictors for CINP development the presence of uncomplicated diabetes (OR: 2.17; p = .039) and grade 2-3 chronic CIPN (OR: 1.61; p < .001) as also the administration of combined paclitaxel plus cisplatin (reference variable), compared to oxaliplatin (OR: 0.18; p = .001) and taxanes (OR: 0.16; p < .001). The increased severity of acute OXAIPN was associated with CINP (OR: 4.51; p < .001). OXA-treated patients with persistent CINP presented a worst likelihood to improve after chemotherapy discontinuation, than patients receiving combined paclitaxel plus cisplatin (OR: 50; p < .001).

CONCLUSION

The incidence of CINP in our cohort was comparable to previous reports, with severities fluctuating upwards during chemotherapy and declined post-chemotherapy. Uncomplicated diabetes, the combined paclitaxel plus cisplatin treatment and the increased severity of acute oxaliplatin neurotoxicity mostly increase the risk for developing CINP. OXA-treated patients present less possibilities to recover from CINP after chemotherapy discontinuation, than other chemotherapies.

Role of pattern recognition receptors in chemotherapy-induced neuropathic pain

Progress in the development of effective chemotherapy is producing a growing population of patients with acute and chronic painful chemotherapy-induced peripheral neuropathy (CIPN), a serious treatment-limiting side effect for which there is currently no US Food and Drug Administration-approved treatment. CIPNs induced by diverse classes of chemotherapy drugs have remarkably similar clinical presentations, leading to the suggestion they share underlying mechanisms. Sensory neurons share with immune cells the ability to detect damage associated molecular patterns (DAMPs), molecules produced by diverse cell types in response to cellular stress and injury, including by chemotherapy drugs. DAMPs, in turn, are ligands for pattern recognition receptors (PRRs), several of which are found on sensory neurons, as well as satellite cells, and cells of the immune system. In the present experiments, we evaluated the role of two PRRs, TLR4 and RAGE, present in dorsal root ganglion (DRG), in CIPN. Antisense (AS)-oligodeoxynucleotides (ODN) against TLR4 and RAGE mRNA were administered intrathecally before ('prevention protocol') or 3 days after ('reversal protocol') the last administration of each of three chemotherapy drugs that treat cancer by different mechanisms (oxaliplatin, paclitaxel and bortezomib). TLR4 and RAGE AS-ODN prevented the development of CIPN induced by all three chemotherapy drugs. In the reversal protocol, however, while TLR4 AS-ODN completely reversed oxaliplatin- and paclitaxel-induced CIPN, in rats with bortezomib-induced CIPN it only produced a temporary attenuation. RAGE AS-ODN, in contrast, reversed CIPN induced by all three chemotherapy drugs. When a TLR4 antagonist was administered intradermally to the peripheral nociceptor terminal, it did not affect CIPN induced by any of the chemotherapy drugs. However, when administered intrathecally, to the central terminal, it attenuated hyperalgesia induced by all three chemotherapy drugs, compatible with a role of TLR4 in neurotransmission at the central terminal but not sensory transduction at the peripheral terminal. Finally, since it has been established that cultured DRG neurons can be used to study direct effects of chemotherapy on nociceptors, we also evaluated the role of TLR4 in CIPN at the cellular level, using patch-clamp electrophysiology in DRG neurons cultured from control and chemotherapy-treated rats. We found that increased excitability of small-diameter DRG neurons induced by in vivo and in vitro exposure to oxaliplatin is TLR4-dependent. Our findings suggest that in addition to the established contribution of PRR-dependent neuroimmune mechanisms, PRRs in DRG cells also have an important role in CIPN.

Patient perceptions of altering chemotherapy treatment due to peripheral neuropathy

PURPOSE

Clinical practice guidelines recommend altering neurotoxic chemotherapy treatment in patients experiencing intolerable chemotherapy-induced peripheral neuropathy (CIPN). The primary objective of this survey was to understand patient's perspectives on altering neurotoxic chemotherapy treatment, including their perceptions of the benefits of preventing irreversible CIPN and the risks of reducing treatment efficacy.

METHODS

A cross-sectional online survey was distributed via social networks to patients who were currently receiving or had previously received neurotoxic chemotherapy for cancer. Survey results were analyzed using descriptive statistics and qualitative analysis.

RESULTS

Following data cleaning, 447 participants were included in the analysis. The median age was 57 years, 93% were white, and most were from the UK (53%) or USA (38%). Most participants who were currently or recently treated expected some CIPN symptom resolution (86%), but 45% of those who had completed treatment more than a year ago reported experiencing no symptom resolution. Participants reported that they would discontinue chemotherapy treatment for less severe CIPN if they knew their symptoms would be permanent than if symptoms would disappear after treatment. Most patients stated that the decision to alter chemotherapy or not was usually made collaboratively between the patient and their treating clinician (61%). The most common reason participants were reluctant to talk with their clinician about CIPN was fear that treatment would be altered. Participants noted a need for improved understanding of CIPN symptoms and their permanence, better patient education relating to CIPN prior to and after treatment, and greater clinician understanding and empathy around CIPN.

CONCLUSIONS

This survey highlights the importance of shared decision-making, including a consideration of both the long-term benefits and risks of altering neurotoxic chemotherapy treatment due to CIPN. Additional work is needed to develop decision aids and other communication tools that can be used to improve shared decision making and help patients with cancer achieve their treatment goals.

Gait analysis in chemotherapy-induced peripheral neurotoxicity rodent models

Gait analysis could be used in animal models as an indicator of sensory ataxia due to chemotherapy-induced peripheral neurotoxicity (CIPN). Over the years, gait analysis in in vivo studies has evolved from simple observations carried out by a trained operator to computerised systems with machine learning that allow the quantification of any variable of interest and the establishment of algorithms for behavioural classification. However, there is not a consensus on gait analysis use in CIPN animal models; therefore, we carried out a systematic review. Of 987 potentially relevant studies, 14 were included, in which different methods were analysed (observation, footprint and CatWalk™). We presented the state-of-the-art of possible approaches to analyse sensory ataxia in rodent models, addressing advantages and disadvantages of different methods available. Semi-automated methods may be of interest when preventive or therapeutic strategies are evaluated, also considering their methodological simplicity and automaticity; up to now, only CatWalk™ analysis has been tested. Future studies should expect that CIPN-affected animals tend to reduce hind paw support due to pain, allodynia or loss of sensation, and an increase in swing phase could or should be observed. Few available studies documented these impairments at the last time point, and only appeared later on respect to other earlier signs of CIPN (such as altered neurophysiological findings). For that reason, gait impairment could be interpreted as late repercussions of loss of sensory.

Efficacy of electroacupuncture in the treatment of peripheral neuropathy caused by Utidelone: Study protocol for a randomized controlled trial

Introduction

Utidelone (UTD1) is a new chemotherapeutic drug for recurrent or metastatic breast cancer. However, it usually leads to severe peripheral neuropathy (PN) and causes numbness of the hands and feet and significant pain in patients' life. Electroacupuncture (EA) is considered beneficial in improving PN and relieving numbness of the hands and feet. This trial aims to evaluate the therapeutic effect of EA on PN caused by UTD1 in patients with advanced breast cancer.

Methods and analysis

This study is a prospective randomized controlled trial. A total of 70 patients with PN caused by UTD1 will be randomly assigned to the EA treatment group and the control group in a ratio of 1:1. The patients in the EA treatment group will receive 2 Hz EA three times a week for 4 weeks. The patients in the control group will take mecobalamin (MeCbl) tablets orally, one tablet each, three times a day for 4 weeks. The main outcome measures will be the evaluation scale of peripheral neurotoxicity of chemotherapeutic drugs according to the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-CIPN 20-item (EORTC QLQ-CIPN20) and the peripheral neurotoxicity assessment rating according to NCI CTCAE version 5.0. Secondary outcomes will be the quality of life scale according to the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire (EORTC QLQ-C30). The results will be evaluated at baseline, post-treatment phase, and follow-up. All major analyses will be based on the intention-to-treat principle.

Ethics and dissemination

This protocol was approved by the Medical Ethics Committee of Zhejiang Cancer Hospital on 26 July 2022. The license number is IRB-2022-425. This study will provide clinical efficacy data on EA in the treatment of PN caused by UTD1 and will help to prove whether EA is an effective and safe therapy. The study results will be shared with healthcare professionals through the publication of manuscripts and conference reports.

Trial registration number

ChiCTR2200062741.

[Mechanisms of platinum-induced peripheral neuropathy in cancer patients]

Chemoinduced polyneuropathy (CIPNP) is a common side-effect of chemotherapy, significantly impairing quality of life in patients treated for cancer. Platinum preparations are the most commonly used chemotherapeutic agents used in the treatment of ovarian, testicular, breast, lung and colon cancers. Clinical examination reveals restrictions on the motor, sensory and autonomic functions of the upper and lower extremities, which occur at different stages of antitumor treatment, seriously complicating the treatment of the underlying disease. Pain and sensory disturbances may persist for months or even years after chemotherapy is completed. Thus, CIPNP is a major problem because it is impossible to predict which patients will develop neurological symptoms, to estimate their timing of manifestation, which can occur at any time during the course of chemotherapy, there is no early indication to reduce the dose of the cytotoxic drug, and there are no drugs that effectively prevent or alleviate the course of neuropathy. This review focuses on neurotoxicity with the use of platinum drugs, including the frequency of occurrence, risk factors, cumulative doses, various pathogenetic mechanisms for the development of CIPNP, clinical features and variants of the neurophysiological picture.

Neurological Complications of Conventional and Novel Anticancer Treatments

Various neurological complications, affecting both the central and peripheral nervous system, can frequently be experienced by cancer survivors after exposure to conventional chemotherapy, but also to modern immunotherapy. In this review, we provide an overview of the most well-known adverse events related to chemotherapy, with a focus on chemotherapy induced peripheral neurotoxicity, but we also address some emerging novel clinical entities related to cancer treatment, including chemotherapy-related cognitive impairment and immune-mediated adverse events. Unfortunately, efficacious curative or preventive treatment for all these neurological complications is still lacking. We provide a description of the possible mechanisms involved to drive future drug discovery in this field, both for symptomatic treatment and neuroprotection.

Sodium-Calcium Exchanger 2: A Pivotal Role in Oxaliplatin Induced Peripheral Neurotoxicity and Axonal Damage?

Oxaliplatin (OHP)-induced peripheral neurotoxicity (OIPN) is a frequent adverse event of colorectal cancer treatment. OIPN encompasses a chronic and an acute syndrome. The latter consists of transient axonal hyperexcitability, due to unbalance in Na+ voltage-operated channels (Na+VOC). This leads to sustained depolarisation which can activate the reverse mode of the Na+/Ca2+ exchanger 2 (NCX2), resulting in toxic Ca2+ accumulation and axonal damage (ADa). We explored the role of NCX2 in in vitro and in vivo settings. Embryonic rat Dorsal Root Ganglia (DRG) organotypic cultures treated with SEA0400 (SEA), a NCX inhibitor, were used to assess neuroprotection in a proof-of-concept and pilot study to exploit NCX modulation to prevent ADa. In vivo, OHP treated mice (7 mg/Kg, i.v., once a week for 8 weeks) were compared with a vehicle-treated group (n = 12 each). Neurophysiological and behavioural testing were performed to characterise acute and chronic OIPN, and morphological analyses were performed to detect ADa. Immunohistochemistry, immunofluorescence, and western blotting (WB) analyses were also performed to demonstrate changes in NCX2 immunoreactivity and protein expression. In vitro, NCX inhibition was matched by ADa mitigation. In the in vivo part, after verifyingboth acute and chronic OIPN had ensued, we confirmed via immunohistochemistry, immunofluorescence, and WB that a significant NCX2 alteration had ensued in the OHP group. Our data suggest NCX2 involvement in ADa development, paving the way to a new line of research to prevent OIPN.

Kratom alkaloid mitragynine: Inhibition of chemotherapy-induced peripheral neuropathy in mice is dependent on sex and active adrenergic and opioid receptors

Mitragynine (MG) is an alkaloid found in Mitragyna speciosa (kratom) that is used as an herbal remedy for pain relief and opioid withdrawal. MG acts at μ-opioid and α-adrenergic receptors in vitro, but the physiological relevance of this activity in the context of neuropathic pain remains unknown. The purpose of the present study was to characterize the effects of MG in a mouse model of chemotherapy-induced peripheral neuropathy (CIPN), and to investigate the potential impact of sex on MG's therapeutic efficacy. Inhibition of oxaliplatin-induced mechanical hypersensitivity was measured following intraperitoneal administration of MG. Both male and female C57BL/6J mice were used to characterize potential sex-differences in MG's therapeutic efficacy. Pharmacological mechanisms of MG were characterized through pretreatment with the opioid and adrenergic antagonists naltrexone, prazosin, yohimbine, and propranolol (1, 2.5, 5 mg/kg). Oxaliplatin produced significant mechanical allodynia of equal magnitude in both male and females, which was dose-dependently attenuated by repeated MG exposure. MG was more potent in males vs females, and the highest dose of MG (10 mg/kg) exhibited greater anti-allodynic efficacy in males. Mechanistically, activity at µ-opioid, α₁- and α₂-adrenergic receptors, but not β-adrenergic receptors contributed to the effects of MG against oxaliplatin-induced mechanical hypersensitivity. Repeated MG exposure significantly attenuated oxaliplatin-induced mechanical hypersensitivity with greater potency and efficacy in males, which has crucial implications in the context of individualized pain management. The opioid and adrenergic components of MG indicate that it shares pharmacological properties with clinical neuropathic pain treatments.

Neuromodulation Therapy for Chemotherapy-Induced Peripheral Neuropathy: A Systematic Review

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and painful condition in patients who have received chemotherapy. The role of neuromodulation therapy in treating pain and improving neurological function in CIPN remains unclear and warrants evidence appraisal. In compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we performed a systematic review to assess change in pain intensity and neurological function after implementation of any neuromodulation intervention for CIPN. Neuromodulation interventions consisted of dorsal column spinal cord stimulation (SCS), dorsal root ganglion stimulation (DRG-S), or peripheral nerve stimulation (PNS). In total, 15 studies utilized SCS (16 participants), 7 studies utilized DRG-S (7 participants), and 1 study utilized PNS (50 participants). Per the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) criteria, there was very low-quality GRADE evidence supporting that dorsal column SCS, DRG-S, and PNS are associated with a reduction in pain severity from CIPN. Results on changes in neurological function remained equivocal due to mixed study findings on thermal sensory thresholds and touch sensation or discrimination. Future prospective, well-powered, and comparative studies assessing neuromodulation for CIPN are warranted.

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.

Application Potential of Plant-Derived Medicines in Prevention and Treatment of Platinum-Induced Peripheral Neurotoxicity

As observed with other chemotherapeutic agents, the clinical application of platinum agents is a double-edged sword. Platinum-induced peripheral neuropathy (PIPN) is a common adverse event that negatively affects clinical outcomes and patients’ quality of life. Considering the unavailability of effective established agents for preventing or treating PIPN and the increasing population of cancer survivors, the identification and development of novel, effective interventions are the need of the hour. Plant-derived medicines, recognized as ideal agents, can not only help improve PIPN without affecting chemotherapy efficacy, but may also produce synergy. In this review, we present a brief summary of the mechanisms of platinum agents and PIPN and then focus on exploring the preventive or curative effects and underlying mechanisms of plant-derived medicines, which have been evaluated under platinum-induced neurotoxicity conditions. We identified 11 plant extracts as well as 17 plant secondary metabolites, and four polyherbal preparations. Their effects against PIPN are focused on oxidative stress and mitochondrial dysfunction, glial activation and inflammation response, and ion channel dysfunction. Also, ten clinical trials have assessed the effect of herbal products in patients with PIPN. The understanding of the molecular mechanism is still limited, the quality of clinical trials need to be further improved, and in terms of their efficacy, safety, and cost effectiveness studies have not provided sufficient evidence to establish a standard practice. But plant-derived medicines have been found to be invaluable sources for the development of natural agents with beneficial effects in the prevention and treatment of PIPN.

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.

Monosialotetrahexosylganglioside in the treatment of chronic oxaliplatin-induced peripheral neurotoxicity: TJMUCH-GI-001, a randomised controlled trial

BACKGROUND

Chronic oxaliplatin-induced peripheral neurotoxicity (OIPN) is the most troublesome and dose-limiting side effect of oxaliplatin. There is no effective treatment for chronic OIPN. We conducted a randomised controlled trial to investigate the efficacy of monosialotetrahexosylganglioside (GM1) in treating chronic OIPN.

METHODS

In this single-centre, double-blind, phase Ⅲ trial, gastrointestinal cancer patients with persistent chronic OIPN were randomised in 1:1 ratio to receive either GM1 or placebo at Tianjin Medical University Cancer Institute and Hospital, China. GM1 was dosed at 60 mg daily for every 3 weeks or 40 mg daily for every 2 weeks. Seven- and fourteen- day infusions were administered to concurrent oxaliplatin users and oxaliplatin discontinuation patients, respectively. The primary endpoint was the relief of neurotoxicity (≥30% improvement), measured by a newly developed patient reported outcome measure (MCIPN) based on prior questionnaires including the European Organization for Research and Treatment of Cancer Quality of Life Chemotherapy Induced Peripheral Neuropathy Questionnaire twenty-item scale. Visual analogue score (VAS) was used as another instrument for patients to evaluate the total Chronic OIPN treatment effect. VAS responders (≥30% improvement), double responders (≥30% improvement in both MCIPN and VAS), and high responders (≥50% improvement in the MCIPN total score) were also calculated. The secondary endpoints were safety and quality of life. The additional endpoints are progression-free survival (PFS), disease-free survival (DFS), overall survival (OS), and tumour response. (Trial registration number: NCT02486198 at ClinicalTrials.gov).

FINDINGS

Between May 2015 to December 2017, 145 patients were randomly assigned to receive either GM1 (n=73) and placebo (n=72). Majority of the patients in both arms (90% in GM1 and 83% in placebo) continued receiving oxaliplatin on the trial. More patients responded in the GM1 group than in the placebo group (MCIPN responders: 53% vs 14%, VAS responders: 49% vs 22%, double responders: 41% vs 7%, and high responders: 32% vs 13%, all P < ·01). Analyses were also performed in concurrent oxaliplatin users. The results were consistent with those of the whole group. No deleterious effects of GM1 on survival or tumour response were found. There were no ≥G3 GM1-related adverse events.

INTERPRETATION

In patients with chronic OIPN, the use of GM1 reduces the severity of chronic OIPN compared with placebo.

FUNDING

This work was supported by clinical trial development fund of Tianjin Medical University Cancer Institute and Hospital (No.C1706).

Chemotherapy and peripheral neuropathy

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a major dose-limiting side effect of many anti-cancer agents, including taxanes, platinums, vinca alkaloids, proteasome inhibitors, immunomodulatory drugs, and antibody-drug conjugates. The resultant symptoms often persist post treatment completion and continue to impact on long-term function and quality of life for cancer survivors. At present, dose reduction remains the only strategy to prevent severe neuropathy, often leading clinicians to the difficult decision of balancing maximal treatment exposure and minimal long-lasting side effects. This review examines the clinical presentations of CIPN with each class of neurotoxic treatment, describing signs, symptoms, and long-term outcomes. We provide an update on the proposed mechanisms of nerve damage and review current data on clinical and genetic risk factors contributing to CIPN development. We also examine recent areas of research in the treatment and prevention of CIPN, with specific focus on current clinical trials and consensus recommendations for CIPN management.

Systematic review of long-term chemotherapy-induced peripheral neuropathy (CIPN) following adjuvant oxaliplatin for colorectal cancer

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is the most common dose-limiting side effect of oxaliplatin. It often persists and can adversely affect quality of life of colorectal cancer (CRC) survivors. This systematic review explored the proportions of patients with persistent CIPN and the reporting methods used.

METHODS

MEDLINE, EMBASE, Web of Science and CINAHL were searched up to March 2021 for publications reporting CIPN outcomes following adjuvant oxaliplatin-containing chemotherapy at prespecified timepoints in participants with CRC. Secondary outcomes assessed the tools used to measure CIPN. Two authors reviewed full text publications for eligibility, data extraction and appraisal. Meta-analysis was performed where Common Terminology Criteria for Adverse Events (any grade) was reported at the most frequent timepoints.

RESULTS

From 7895 citations identified, 27 studies met the eligibility criteria: six were randomised control trials, and 21 were non-randomised studies. Pooled prevalence of CIPN at 6, 12, 24 and 36 months after chemotherapy were 58%, 45%, 32% and 24% respectively. The average prevalence of CIPN decreased by 26% per year after chemotherapy (pooled RR = 0.74; 95% CI 0.72-0.75). Across all studies, ten separate tools were used as the primary measure of CIPN. Quality appraisal identified open-label design and inadequate reporting of participants lost to follow-up as the main methodological limitations.

CONCLUSION

Our summary of reported rates of persistent CIPN indicates substantial long-term toxicity affecting CRC survivors, and will help clinicians estimate CIPN risk and its change over time. The heterogeneity of CIPN measures identified in the review highlights the need for a standardised CIPN assessment.

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.

Patient-centric decision framework for treatment alterations in patients with Chemotherapy-induced Peripheral Neuropathy (CIPN)

Recently updated American Society of Clinical Oncology (ASCO) guidelines for Prevention and Management of Chemotherapy-Induced Peripheral Neuropathy (CIPN) in Survivors of Adult Cancers make a single recommendation to alter treatment by delaying, decreasing, or discontinuing dosing in patients who develop CIPN during neurotoxic chemotherapy treatment. Dosing guidelines have inconsistent recommendations for when (i.e., what CIPN severity) and how (i.e., delay, decrease, or discontinue) to alter neurotoxic chemotherapy treatment in patients with CIPN. Clinical decision making requires an understanding the benefits and risks of treatment alteration, in addition to consideration of other disease and patient factors. This review summarizes four areas of literature and culminates in a patient-centric decision framework to guide clinicians in helping patients to make treatment alteration decisions. First, we describe the current practice of altering treatment due to CIPN, including treatment alteration recommendations and published rates. Second, we summarize the potential benefits of treatment alteration including the reduction in CIPN severity and persistence. Third, we evaluate the potential risk of treatment alteration in compromising treatment efficacy by reviewing prospective trials comparing dosing regimens and retrospective analyses of the effect of relative dose intensity on efficacy. Fourth, we summarize disease and patient factors that should be considered when making a treatment alteration decision for a patient. We then propose a patient-centric decision framework that clinicians can use to assess an individual patient's current and anticipated future CIPN severity and compare that to their maximum tolerable severity to determine whether they should continue, delay, decrease, or discontinue neurotoxic chemotherapy.

Oxaliplatin Depolarizes the IB4- Dorsal Root Ganglion Neurons to Drive the Development of Neuropathic Pain Through TRPM8 in Mice

Use of chemotherapy drug oxaliplatin is associated with painful peripheral neuropathy that is exacerbated by cold. Remodeling of ion channels including TRP channels in dorsal root ganglion (DRG) neurons contribute to the sensory hypersensitivity following oxaliplatin treatment in animal models. However, it has not been studied if TRP channels and membrane depolarization of DRG neurons serve as the initial ionic/membrane drives (such as within an hour) that contribute to the development of oxaliplatin-induced neuropathic pain. In the current study, we studied in mice (1) in vitro acute effects of oxaliplatin on the membrane excitability of IB4⁺ and IB4^- subpopulations of DRG neurons using a perforated patch clamping, (2) the preventative effects of a membrane-hyperpolarizing drug retigabine on oxaliplatin-induced sensory hypersensitivity, and (3) the preventative effects of TRP channel antagonists on the oxaliplatin-induced membrane hyperexcitability and sensory hypersensitivity. We found (1) IB4⁺ and IB4^- subpopulations of small DRG neurons displayed previously undiscovered, substantially different membrane excitability, (2) oxaliplatin selectively depolarized IB4^- DRG neurons, (3) pretreatment of retigabine largely prevented oxaliplatin-induced sensory hypersensitivity, (4) antagonists of TRPA1 and TRPM8 channels prevented oxaliplatin-induced membrane depolarization, and (5) the antagonist of TRPM8 largely prevented oxaliplatin-induced sensory hypersensitivity. These results suggest that oxaliplatin depolarizes IB4^- neurons through TRPM8 channels to drive the development of neuropathic pain and targeting the initial drives of TRPM8 and/or membrane depolarization may prevent oxaliplatin-induce neuropathic pain.

Prospective Evaluation of Health Care Provider and Patient Assessments in Chemotherapy-Induced Peripheral Neurotoxicity

BACKGROUND AND OBJECTIVE

There is no agreement on the gold standard for detection and grading of chemotherapy-induced peripheral neurotoxicity (CIPN) in clinical trials. The objective is to perform an observational prospective study to assess and compare patient-based and physician-based methods for detection and grading of CIPN.

METHODS

Consecutive patients, aged 18 years or older, candidates for neurotoxic chemotherapy, were enrolled in the United States, European Union, or Australia. A trained investigator performed physician-based scales (Total Neuropathy Score-clinical [TNSc], used to calculate Total Neuropathy Score-nurse [TNSn]) and supervised the patient-completed questionnaire (Functional Assessment of Cancer Treatment/Gynecologic Oncology Group-Neurotoxicity [FACT/GOG-NTX]). Evaluations were performed before and at the end of chemotherapy. On participants without neuropathy at baseline, we assessed the association between TNSc, TNSn, and FACT/GOG-NTX. Considering a previously established minimal clinically important difference (MCID) for FACT/GOG-NTX, we identified participants with and without a clinically important deterioration according to this scale. Then, we calculated the MCID for TNSc and TNSn as the difference in the mean change score of these scales between the 2 groups.

RESULTS

Data from 254 participants were available: 180 (71%) had normal neurologic status at baseline. At the end of the study, 88% of participants developed any grade of neuropathy. TNSc, TNSn, and FACT/GOG-NTX showed good responsiveness (standardized mean change from baseline to end of chemotherapy >1 for all scales). On the 153 participants without neuropathy at baseline and treated with a known neurotoxic chemotherapy regimen, we verified a moderate correlation in both TNSc and TNSn scores with FACT/GOG-NTX (Spearman correlation index r = 0.6). On the same sample, considering as clinically important a change in the FACT/GOG-NTX score of at least 3.3 points, the MCID was 3.7 for TNSc and 2.8 for the TNSn.

CONCLUSIONS

MCID for TNSc and TNSn were calculated and the TNSn can be considered a reliable alternative objective clinical assessment if a more extended neurologic examination is not possible. The FACT/GOG-NTX score can be reduced to 7 items and these items correlate well with the TNSc and TNSn.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that a patient-completed questionnaire and nurse-assessed scale correlate with a physician-assessed scale.

Clinical and biochemical markers in CIPN: A reappraisal

The increased survival of cancer patients has raised growing public health concern on associated long-term consequences of antineoplastic treatment. Chemotherapy-induced peripheral neuropathy (CIPN) is a primarily sensory polyneuropathy, which may be accompanied by pain, autonomic disturbances, and motor deficit. About 70% of treated cancer patients might develop CIPN during or after the completion of chemotherapy, and in most of them such complication persists after six months from the treatment. The definition of the potential risk of development and resolution of CIPN according to a clinical and biochemical profile would be certainly fundamental to tailor chemotherapy regimen and dosage on individual susceptibility. In recent years, patient-reported and clinician-related tools along with quality of life instruments have been featured as primary outcomes in clinical setting and randomized trials. New studies on metabolomics markers are further pursuing accurate and easily accessible indicators of peripheral nerve damage. The aim of this review is to outline the strengths and pitfalls of current knowledge on CIPN, and to provide a framework for future potential developments of standardized protocols involving clinical and biochemical markers for CIPN assessment and monitoring.

Chemotherapy-induced peripheral neuropathy (CIPN): current therapies and topical treatment option with high-concentration capsaicin

Cancer diagnosis and treatment are drastic events for patients and their families. Besides psychological aspects of the disease, patients are often affected by severe side effects related to the cancer itself or as a result of therapeutic interventions. Particularly, chemotherapy-induced peripheral neuropathy (CIPN) is the most prevalent neurological complication of oral or intravenous chemotherapy. The disorder may require dose reduction of chemotherapy and is accompanied by multiple symptoms with long-term functional impairment affecting quality of life (QoL), e.g., sensory and functional deteriorations as well as severe pain. Although CIPN may reverse or improve after termination of the causative chemotherapy, approximately 30–40% of patients are faced with chronicity of the symptoms. Due to the advantages in cancer diagnosis and treatments, survival rates of cancer patients rise and CIPN may occur even more frequently in the future. In this review, we summarize current recommendations of leading national and international societies regarding prevention and treatment options in CIPN. A special focus will be placed on current evidence for topical treatment of CIPN with high-dose capsaicin. Finally, an algorithm for CIPN treatment in clinical practice is provided, including both pharmacologic and non-pharmacologic modalities based on the clinical presentation.

A Cross-Sectional Study of Sub-Basal Corneal Nerve Reduction Following Neurotoxic Chemotherapy

Purpose

Sub-basal corneal nerves have been shown to change during neurotoxic chemotherapy treatment. This cross-sectional study investigated corneal nerve morphology in patients who have completed neurotoxic chemotherapy well after treatment cessation and its association with peripheral nerve function.

Methods

Central corneal nerve fiber length (CNFL) and inferior whorl length (IWL), average nerve fiber length (ANFL), corneal nerve fiber density (CNFD) and corneal nerve branch density (CNBD), and nerve fiber area (CNFA) were examined using in vivo corneal confocal microscopy in patients with cancer who had completed treatment with either paclitaxel or oxaliplatin between 3 and 24 months prior to assessment in comparison with 2 separate groups of healthy controls. Neurological assessments were conducted including clinician- and patient-reported outcomes, and neurological grading scales.

Results

Both paclitaxel- (n = 40) and oxaliplatin-treated (n = 30) groups had reduced IWL and ANFL compared to the respective healthy control groups (n = 15 in each group) (paclitaxel: IWL = P = 0.02, ANFL = P = 0.009; and oxaliplatin: IWL = P = 0.008, ANFL P = 0.02). CNFL and CNFD reduction were observed only in the paclitaxel-treated group compared with healthy controls (P = 0.008 and P = 0.02, respectively), whereas CNFA was reduced in the oxaliplatin-treated group (P = 0.04). IWL reduction correlated with worse fine hand dexterity in chemotherapy-treated patients (r = −0.33, P = 0.007).

Conclusions

There is evidence of corneal nerve loss in patients with cancer who have been treated with paclitaxel and oxaliplatin well after treatment cessation associated with worse upper limb function.

Translational Relevance

Sub-basal corneal nerve reduction is evident even after cessation of neurotoxic treatment. In vivo corneal confocal microscopy may be useful in the monitoring of nerve function in patients receiving chemotherapy.

Duloxetine against symptomatic chemotherapy-induced peripheral neurotoxicity in cancer survivors: a real world, open-label experience

The objective of this observational study was to evaluate the efficacy and safety of duloxetine in a cohort of 100 cancer survivors with chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN was graded employing the TNSc and the NCI-CTCv4. The Patient Global Impression of Change (PGIC) scale measured the efficacy of duloxetine (1: no benefit; to 7: excellent response). A clinically meaningful response was considered a PGIC > 4. Median age was 62 (29-81) years and 42% were male. CIPN was graded as grades 1, 2 and 3 in 20, 66, and 14% of patients, respectively. Median time to duloxetine initiation was 6 (1-63) months after chemotherapy. Fifty-seven patients early dropped out from duloxetine, due to lack of efficacy (20%) or side effects (37%). Male patients more frequently discontinued duloxetine due to lack of efficacy (35.7 vs. 8.6% P = 0.001). PGIC scores were higher in female patients (4 vs. 1, P = 0.001), taxane-treated patients (4 vs. 1, P = 0.042) and with short-lasting (<6 months) CIPN (4 vs. 1, P = 0.008). Patients with long-lasting CIPN had a higher rate of adverse events (47 vs. 27%, P = 0.038) and discontinuation (54.8 vs. 45.1%, P = 0.023). In the multivariate analysis, female gender and short-lasting CIPN were independently associated with a favorable response to duloxetine. Low tolerability, male gender, and long-lasting CIPN significantly limited duloxetine use in daily practice setting. A minority of cancer survivors with CIPN treated with duloxetine had a meaningful CIPN improvement, and tolerability was overall low. Female gender and short-term CIPN were independently associated with a favorable response to duloxetine.

Oxaliplatin rechallenge in metastatic colorectal cancer patients with clinically significant oxaliplatin-induced peripheral neurotoxicity

We investigated whether rechallenge with oxaliplatin (OXA) can worsen the pre-existing oxaliplatin-induced peripheral neurotoxicity (OXAIPN) in metastatic colorectal cancer (mCRC) patients. Patients previously treated with OXA, having clinically significant grade 1 or 2 OXAIPN were assessed, after receiving rechallenge with OXA, using the clinical version of the Total Neuropathy Score (TNSc). Peripheral neuropathy was assessed at the end of first OXA exposure and at completion of OXA rechallenge. The first line OXA-based chemotherapy was completed at least 9 months earlier (OXA-free interval). We studied 25 mCRC patients, 14 males and 11 females, with a median age of 63 (35-77) years. After their first exposure to OXA-based chemotherapy, 9 (36%) patients developed grade 1 OXAIPN and 16 patients grade 2 (64%) neurotoxicity. OXA reintroduction with a median of 10 (8-14) cycles led to grade 1 OXAIPN in two patients (8%), grade 2 in 19 patients (76%), and grade 3 neuropathy in 4 (16%) patients Worsening of pre-existing OXAIPN was documented in seven (28%) patients and was significantly associated with higher OXA delivered cumulative dose (P < .001). Median TNSc scores following treatment (10; range 4-18) were significantly increased (P < .001), when compared to the scores recorded at the end of first line treatment (8; range 2-12). Rechallenging OXA appears to relatively worsen the severity of existing OXAIPN. However, the majority of rechallenged patients developed a clinically significant (grade 2) OXAIPN, rather than treatment-emergent grade 3. As such, OXA rechallenge might be a feasible option in patients previously having OXAIPN.

Herbal Decoction Divya-Peedantak-Kwath Alleviates Allodynia and Hyperalgesia in Mice Model of Chemotherapy-Induced Peripheral Neuropathy via Modulation in Cytokine Response

The widely used cancer treatment, chemotherapy, causes severe long-term neuropathic pain in 30–40% cases, the condition clinically known as chemotherapy-induced peripheral neuropathy (CIPN). Approved conventional analgesics are sometimes ineffective, while others like opioids have undesirable side effects like addiction, seizures, and respiratory malfunctioning. Tricyclic antidepressants and anticonvulsants, although exhibit anti-allodynic effects in neuropathy, also have unpleasant side effects. Thus, alternative medicines are being explored for CIPN treatment. Despite scattered reports on different extracts from different plants having potential anti-allodynic effects against CIPN, no established medicine or formulation of herbal origin exists. In this study, efficacy of an herbal decoction, formulated based on ancient medicinal principles and protocols for treating neuropathic pain, Divya-Peedantak-Kwath (DPK), has been evaluated in a paclitaxel (PTX)-induced peripheral neuropathic mouse model. We observed that DPK has prominent anti-allodynic and anti-hyperalgesic effects and acts as a nociceptive modulator for CIPN. With exhibited antioxidative effects, DPK restored the redox potential of the sciatic nerves to the normal. On histopathological evaluation, DPK prevented the PTX-induced lesions in the sciatic nerve, in a dose-dependent manner. It also prevented inflammation by modulating the levels of pro-inflammatory cytokines involved in CIPN pathogenesis. Our observations evinced that DPK can alleviate CIPN by attenuating oxidative stress and concomitant neuroinflammation through immune modulation.

The relevance of multimodal assessment in experimental oxaliplatin-induced peripheral neurotoxicity

Chemotherapy-induced peripheral neurotoxicity represents one of the most relevant dose-limiting side effects that can affect cancer patients treated with the common antineoplastic agents. Since the severity of neurotoxicity often leads to dose reduction or early cessation of chemotherapy, the investigation of molecular mechanisms underlying chemotherapy-induced peripheral neurotoxicity is an urgent clinical need in order to better understand its physiopathology and find effective strategies for neuroprotection. Several in vivo preclinical models of chemotherapy-induced peripheral neurotoxicity have been developed but a great variability in mouse strain, dose, route of administration of the drug, treatment schedule and assessment of neurotoxicity is observed between the different published studies making difficult the comparison and interpretation of their results. In many of these studies only behavioural tests are used as outcome measures, while possible neurophysiological and neuropathological changes are not evaluated. In this study, focused on experimental oxaliplatin-induced peripheral neurotoxicity, we reproduced and compared four mouse models with very different drug dose (low or high dose-intensity) and treatment schedules (short or long-term treatment), selected from the literature. Using a multimodal assessment based on behavioural, neurophysiological and neuropathological methods, we evidenced remarkable differences in the results obtained in the selected animal models. This work suggests the importance of a multimodal approach including extensive pathological investigation to confirm the behavioural results.

Comparison of high tone therapy and transcutaneous electrical nerve stimulation therapy in chemotherapy-induced polyneuropathy

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is a worldwide concern in patients receiving neurotoxic agents for cancer therapy. High tone external muscle stimulation is a promising therapeutic approach to alleviate symptoms of CIPN.

METHODS

This pilot study aims to investigate whether the application of home-based high-tone external muscle stimulation therapy (HTEMS) improves symptoms of CIPN. The trial is planned as a therapist- and assessor-blinded, 1:1 randomized controlled study. A total of 50 patients with chemotherapy-induced peripheral polyneuropathy will be included. All patients will perform therapy at home. Study participants will be allocated randomly to the HTEMS therapy (intervention group) or to the transcutaneous electrical nerve stimulation (TENS, control group), respectively, following a standardized therapy schedule. Compliance of participants can be verified by reading out the tool box. Outcomes will be evaluated at baseline and after 8 weeks of home-based therapy. The primary outcome includes improvement of CIPN according to the patient-reported EORTC QLQ-CIPN 20 questionnaire. Secondary outcomes are the patient-reported change in health-related quality of life and clinician-reported changes of vibration sensibility, tendon reflexes, temperature sensibility, perception of touch, and strength of the lower leg muscles. Further a safety- and process evaluation will be performed.

DISCUSSION

This pilot RCT aims to evaluate the impact of home-based HTEMS as compared to TENS in CIPN. There is a need for an effective treatment for CIPN and the results of this study are expected to possibly identify a novel and effective treatment strategy in the future.

Real world, open label experience with lacosamide against acute painful oxaliplatin-induced peripheral neurotoxicity

We report the outcome of a pilot, open-label study that tested the potential of lacosamide (200 mg/bi.d) as an effective and safe symptomatic treatment against acute painful oxaliplatin-induced peripheral neurotoxicity (OXAIPN). Lacosamide was introduced in 18 colorectal cancer patients with evidence of clinically significant acute, painful OXAIPN after infusion of the third course (T1) of oxaliplatin-based chemotherapy (FOLFOX4) and was maintained until completion of all 12 courses (T4). The OXA-Neuropathy Questionnaire (OXA-NQ) was used to record the severity of acute OXAIPN; the PI-NRS estimated the severity of neuropathic pain, while the chronic OXAIPN was graded with TNSc. The EuroQOL (EQ-5D) instrument was also applied. The Patient Global Impression of Change (PGIC) scale measured the lacosamide-attributed perception of change. LCM-responders were considered those with ≥50% reduction in PI-NRS and OXA-NQ scores at T4, compared to T1. Patients experienced on T1 a median number of acute OXAIPN symptoms of 4 and had a median neuropathic pain severity score of 6, which was strongly related to lower quality of life, according to EQ-VAS (P < .001). At T4, 12 patients (66.7%) were classified as responders. A significant clinical improvement was documented in the severity of acute OXAIPN and neuropathic pain in relation to lacosamide (P < .001) at T4 compared to T1, which was associated with improved EQ-VAS scores (P < .001). Twelve patients scored PGIC ≥5 (lacosamide-attributed) at T4. There were no incidences of early drop-outs for safety reasons. Lacosamide appears to be an effective and well-tolerated symptomatic treatment against acute, painful OXAIPN.

Platinum-induced peripheral neurotoxicity: From pathogenesis to treatment

Platinum-induced peripheral neurotoxicity (PIPN) is a common side effect of platinum-based chemotherapy that may cause dose reduction and discontinuation, with oxaliplatin being more neurotoxic. PIPN includes acute neurotoxicity restricted to oxaliplatin, and chronic non-length-dependent sensory neuronopathy with positive and negative sensory symptoms and neuropathic pain in both upper and lower limbs. Chronic sensory axonal neuropathy manifesting as stocking-and-glove distribution is also frequent. Worsening of neuropathic symptoms after completing the last chemotherapy course may occur. Motor and autonomic involvement is uncommon. Ototoxicity is frequent in children and more commonly to cisplatin. Platinum-based compounds result in more prolonged neuropathic symptoms in comparison to other chemotherapy agents. Patient reported outcomes questionnaires, clinical evaluation and instrumental tools offer complementary information in PIPN. Electrodiagnostic features include diffusely reduced/abolished sensory action potentials, in keeping with a sensory neuronopathy. PIPN is dependent on cumulative dose but there is a large variability in its occurrence. The search for additional risk factors for PIPN has thus far yielded no consistent findings. There are currently no neuroprotective strategies to reduce the risk of PIPN, and symptomatic treatment is limited to duloxetine that was found effective in a single phase III intervention study. This review critically examines the pathogenesis, incidence, risk factors (both clinical and pharmacogenetic), clinical phenotype and management of PIPN.

Predictive clinical factors of chronic peripheral neuropathy induced by oxaliplatin

PURPOSE

We aimed to identify potential clinical parameters that can be easily obtained by a pre-treatment clinicopathological evaluation and whole blood test to estimate the development of oxaliplatin-induced peripheral neuropathy (OIPN).

METHODS

This study was conducted retrospectively. For the FOLFOX regimen, patients received oxaliplatin, 85 mg/m², every 2 weeks for 12 courses, and with the XELOX regimen, oxaliplatin was 130 mg/m², every 3 weeks for 6-8 courses. The incidence and degree of neuropathy (NCI-CTCAE v.3) were recorded.

RESULTS

A total of 186 patients were included in the study. There were 108 (58%) patients in the grade 0-1 (G0-G1) neuropathy group (mean age 50.5 ± 11.5; 63% men), and 78 (42%) patients in the grade 2-3 (G2-G3) neuropathy group (mean age 58.0 ± 10.8; 46.2% men). The relationship between G2-G3 OIPN development and age (p < 0.001), gender (p = 0.02), and ECOG performance status (p = 0.007) was statistically significant. In the G2-G3 neuropathy group, serum gamma-glutamyl transferase (GGT) (p < 0.001) and glucose (p = 0.007) levels were higher, whereas vitamin D (p < 0.001), hemoglobin (Hgb) (p < 0.001), serum albumin (p = 0.001), and serum magnesium (p = 0.035) levels were lower compared with the G0-G1 neuropathy group. G2-G3 neuropathy was observed in 88% of patients with mucinous carcinoma pathologic type (p < 0.001).

CONCLUSION

This study demonstrated that age, histopathologic type, albumin, GGT, glucose, vitamin D, and Hgb levels were the effective factors in prediction of the development of OIPN. In addition, GGT, vitamin D, and Hgb levels were the most effective factor to predict development of OIPN.

Sexually dimorphic therapeutic response in bortezomib-induced neuropathic pain reveals altered pain physiology in female rodents

Chemotherapy-induced neuropathic pain (CINP) in both sexes compromises many current chemotherapeutics and lacks an FDA-approved therapy. We recently identified the sphingosine-1-phosphate receptor subtype 1 (S1PR1) and A3 adenosine receptor subtype (A3AR) as novel targets for therapeutic intervention. Our work in male rodents using paclitaxel, oxaliplatin, and bortezomib showed robust inhibition of CINP with either S1PR1 antagonists or A3AR agonists. The S1PR1 functional antagonist FTY720 (Gilenya) is FDA-approved for treating multiple sclerosis, and selective A3AR agonists are in advanced clinical trials for cancer and inflammatory disorders, underscoring the need for their expedited trials in patients with CINP as chemotherapy adjuncts. Our findings reveal that S1PR1 antagonists and A3AR agonists mitigate paclitaxel and oxaliplatin CINP in female and male rodents, but failed to block or reverse bortezomib-induced neuropathic pain (BINP) in females. Although numerous mechanisms likely underlie these differences, we focused on receptor levels. We found that BINP in male rats, but not in female rats, was associated with increased expression of A3AR in the spinal cord dorsal horn, whereas S1PR1 levels were similar in both sexes. Thus, alternative mechanisms beyond receptor expression may account for sex differences in response to S1PR1 antagonists. Morphine and duloxetine, both clinical analgesics, reversed BINP in female mice, demonstrating that the lack of response is specific to S1PR1 and A3AR agents. Our findings suggest that A3AR- and S1PR1-based therapies are not viable approaches in preventing and treating BINP in females and should inform future clinical trials of these drugs as adjuncts to chemotherapy.

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.

Chemotherapy-induced peripheral neurotoxicity: A multifaceted, still unsolved issue

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a potentially dose-limiting side effect of several commonly used cytotoxic chemotherapy agents. The main pharmacological classes that may cause CIPN include classical anticancer drugs, as well as the recently introduced immune checkpoint inhibitors and antibody drug conjugates. The absence of a complete knowledge of CIPN pathophysiology is only one of the several unsolved issues related to CIPN. Among some of the most relevant aspects of CIPN deserving further attention include the real number of patients exposed to the risk of CIPN, the long-term impact on cancer survivors' quality of life due to incomplete recovery from CIPN, the economic burden related to acute and chronic CIPN, and the different perspective and education of the healthcare specialists in charge of managing patients with CIPN. Overall, CIPN remains a very challenging area of research as there are still several unresolved issues to be addressed in the future. In this special issue, the multifaceted profile of CIPN will be presented, with particular emphasis on bolstering the need to develop more optimized outcome measures than the existing ones to accurately evaluate the extent of CIPN, but also to ascertain the differences in the incidence, risk factors, clinical phenotype, and management of CIPN, according to the most commonly used neurotoxic chemotherapy classes. Perspectives for future research to pursue in order to cover the gaps in knowledge in the CIPN field will also be discussed.

Neuroprotective Effects of an Aqueous Extract of Forsythia viridissima and Its Major Constituents on Oxaliplatin-Induced Peripheral Neuropathy

The dried fruits of Forsythia viridissima have been prescribed to relive fever, pain, vomiting, and nausea in traditional medicine. Oxaliplatin (LOHP) is used to treat advanced colorectal cancer; however, it frequently induces peripheral neuropathies. This study was done to evaluate the neuroprotective effects of an aqueous extract of Forsythia viridissima fruits (EFVF) and its major constituents. Chemical constituents from EFVF were characterized and quantified with the UHPLC-diode array detector method, and three major constituents were identified as arctiin, matairesinol, and arctigenin. The in vitro cytotoxicity was measured by the Ez-cytox viability assay, and the in vivo neuroprotection activity was evaluated by a von Frey test in two rodent animal models that were administered LOHP. EFVF significantly alleviated the LOHP-induced mechanical hypersensitivity in the induction model. EFVF also prevented the induction of mechanical hyperalgesia by LOHP in the pre- and co-treatment of LOHP and EFVF. Consistently, EFVF exerted protective effects against LOHP-induced neurotoxicity as well as inhibited neurite outgrowths in PC12 and dorsal root ganglion cells. Among the major components of EFVF, arctigenin and matairesinol exerted protective effects against LOHP-induced neurotoxicity. Therefore, EFVF may be useful for relieving or preventing LOHP-induced peripheral neuropathy in cancer patients undergoing chemotherapy with LOHP.

Mechanisms of Chemotherapy-Induced Peripheral Neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most frequent side effects caused by antineoplastic agents, with a prevalence from 19% to over 85%. Clinically, CIPN is a mostly sensory neuropathy that may be accompanied by motor and autonomic changes of varying intensity and duration. Due to its high prevalence among cancer patients, CIPN constitutes a major problem for both cancer patients and survivors as well as for their health care providers, especially because, at the moment, there is no single effective method of preventing CIPN; moreover, the possibilities of treating this syndrome are very limited. There are six main substance groups that cause damage to peripheral sensory, motor and autonomic neurons, which result in the development of CIPN: platinum-based antineoplastic agents, vinca alkaloids, epothilones (ixabepilone), taxanes, proteasome inhibitors (bortezomib) and immunomodulatory drugs (thalidomide). Among them, the most neurotoxic are platinum-based agents, taxanes, ixabepilone and thalidomide; other less neurotoxic but also commonly used drugs are bortezomib and vinca alkaloids. This paper reviews the clinical picture of CIPN and the neurotoxicity mechanisms of the most common antineoplastic agents. A better understanding of the risk factors and underlying mechanisms of CIPN is needed to develop effective preventive and therapeutic strategies.

Prospective Study of the Clinical, Electrophysiologic, and Sonographic Characteristics of Oxaliplatin-Induced Neuropathy

BACKGROUND AND PURPOSE

Oxaliplatin-induced neuropathy is a major dose limiting side effect of the highly effective combination chemotherapy with oxaliplatin, irinotecan, and 5-fluorouracil (FOLFIRINOX) in patients with metastastic pancreatic cancer. We present the first longitudinal sonographical-electrophysiological study on oxaliplatin-induced neuropathy.

METHODS

Thirteen patients with metastatic pancreatic cancer underwent clinical, sonographic, and electrophysiological evaluation before, 3 and 7 months after treatment with 12 two-week cycles of FOLFIRINOX.

RESULTS

The majority of patients (61%) developed symptoms and electrophysiological signs of a length-dependent sensorimotor axonal neuropathy 7 months after treatment initiation. Oxaliplatin-induced neuropathy presented with a cross-sectional area (CSA) increase of mostly the tibial and fibular nerve, which developed parallel or prior to clinical signs and electrophysiological changes. Furthermore, isolated CSA at entrapment sites of the upper and lower extremities was measured without relevant symptoms. No correlation between sonographic and electrophysiological findings or clinical severity was detected.

CONCLUSIONS

Oxaliplatin-induced neuropathy is characterized by an axonal length-dependent nerve affection presenting with a combination of sonographical and electrophysiological alterations.

An updated understanding of the mechanisms involved in chemotherapy-induced neuropathy

The burdensome condition of chemotherapy-induced peripheral neuropathy occurs with various chemotherapeutics, including bortezomib, oxaliplatin, paclitaxel and vincristine. The symptoms, which include pain, numbness, tingling and loss of motor function, can result in therapy titrations that compromise therapy efficacy. Understanding the mechanisms of chemotherapy-induced peripheral neuropathy is therefore essential, yet incompletely understood. The literature presented here will address a multitude of molecular and cellular mechanisms, beginning with the most well-understood cellular and molecular-level changes. These modifications include alterations in voltage-gated ion channels, neurochemical transmission, organelle function and intracellular pathways. System-level alterations, including changes to glial cells and cytokine activation are also explored. Finally, we present research on the current understanding of genetic contributions to this condition. Suggestions for future research are provided.

Rechallenge with oxaliplatin and peripheral neuropathy in colorectal cancer patients

BACKGROUND

Oxaliplatin (OXA) is a cornerstone in the treatment of colorectal cancer (CRC). Retreatment with OXA is frequently considered as salvage treatment. OXA-induced neuropathy (OIN) is the most frequent and feared long-term side effect.

PATIENTS AND METHODS

CRC patients receiving at least twice OXA-based chemotherapy lines at our institution between June 2000 and July 2016 were reviewed. The aim of this study was to investigate whether retreatment with OXA increases the risk of developing new or worsening previous neuropathy. OIN was assessed by National Cancer Institute-Common Toxicity Criteria for Adverse Events (NCI), Total Neuropathy Score© (TNS) and nerve-conduction studies.

RESULTS

106 patients were included in the analysis. Median age at OXA-based retreatment was 61.5 (20-83) years. After the first OXA-based chemotherapy treatment, 63.4% of patients developed OIN, 30.7 and 8.9% grades 2 and 3, respectively, after a median of 11 (1-17) cycles. After 30 (11-90) months of median to retreatment with a median of 8 (1-14) OXA cycles, 39.6, 22.6, and 0% of patients developed grade 1, 2, and 3 OIN, respectively. Worsening of the previous OIN was observed in one-third (31.1%) of all patients. OXA-cumulative dose was independently associated with greater risk of worsening OIN (p < 0.001). Non-significant trend towards higher TNSc© scores after retreatment was observed [5 (0-11) vs 6 (3-13), p = 0.083].

CONCLUSION

Retreatment with OXA in CRC patients is a feasible option even in patients who previously developed moderate or severe OIN. One-third of patients' OIN was worsened by retreatment. Neurological monitoring should be considered.

Balance and Gait Impairment: Sensor-Based Assessment for Patients With Peripheral Neuropathy

BACKGROUND

Individuals with peripheral neuropathy (PN) frequently experience balance and gait impairments that can lead to poor physical function, falls, and injury. Nurses are aware that patients with cancer experience balance and gait impairments but are unsure of optimal assessment and management strategies.

OBJECTIVES

This article reviews options for balance and gait assessment for patients diagnosed with cancer experiencing PN, describes advantages and limitations of the various options, and highlights innovative, clinically feasible technologies to improve clinical assessment and management.

METHODS

The literature was reviewed to identify and assess the gold standard quantitative measures for assessing balance and gait.

FINDINGS

Gold standard quantitative measures are burdensome for patients and not often used in clinical practice. Sensor-based technologies improve balance and gait assessment options by calculating precise impairment measures during performance of simple clinical tests at the point of care.

Chemotherapy-induced pain is promoted by enhanced spinal adenosine kinase levels through astrocyte-dependent mechanisms

Development of chemotherapy-induced neuropathic pain (CINP) compromises the use of chemotherapy and greatly impacts thousands of lives. Unfortunately, there are no Food and Drug Administration-approved drugs to prevent or treat CINP. Neuropathological changes within CNS, including neuroinflammation and increased neuronal excitability, are driven by alterations in neuro-glia communication; but, the molecular signaling pathways remain largely unexplored. Adenosine is a potent neuroprotective purine nucleoside released to counteract the consequences of these neuropathological changes. Adenosine signaling at its adenosine receptors (ARs) is dictated by adenosine kinase (ADK) in astrocytes, which provides a cellular sink for the removal of extracellular adenosine. We now demonstrate that chemotherapy (oxaliplatin) in rodents caused ADK overexpression in reactive astrocytes and reduced adenosine signaling at the A3AR subtype (A3AR) within the spinal cord. Dysregulation of ADK and A3AR signaling was associated with increased proinflammatory and neuroexcitatory interleukin-1β expression and activation of nucleotide-binding oligomerization domain-like receptor protein 3 inflammasome, but not putative oxaliplatin-associated GSK3β transcriptional regulation. Intrathecal administration of the highly selective A3AR agonist MRS5698 attenuated IL-1β production and increased the expression of potent anti-inflammatory and neuroprotective IL-10. The effects of MRS5698 were blocked by attenuating IL-10 signaling in rats with intrathecal neutralizing IL-10 antibody and in IL-10 knockout mice. These findings provide new molecular insights implicating astrocyte-based ADK-adenosine axis and nucleotide-binding oligomerization domain-like receptor protein 3 in the development of CINP and IL-10 in the mechanism of action of A3AR agonists. These findings strengthen the pharmacological rationale for clinical evaluation of A3AR agonists already in advanced clinical trials as anticancer agents as an adjunct to chemotherapy.

Rechallenge of oxaliplatin-containing regimens in the third- or later-line therapy for patients with heavily treated metastatic colorectal cancer

Purpose

The third- or later-line therapy available often yield poor survival benefit in patients metastatic colorectal cancer (mCRC). The retrospective study aimed to evaluate efficacy of rechallenge of oxaliplatin-containing regimens.

Patients and methods

Patients with mCRC who progressed from fluoropyrimidine, oxaliplatin, and irinotecan in the first- and second-line chemotherapy, were treated by reexposure to oxaliplatin-containing regimen. Patients treated by anti-epidermal growth factor receptor (EGFR) antibodies with irinotecan were included in the control arm.

Results

Ninety-five and 29 patients were treated with either oxaliplatin reexposure or anti-EGFR antibodies with irinotecan, respectively, as the third- or later-line therapy. The median time to treatment failure (TTF) and overall survival (OS) was 3.77 and 12.17 months in the oxaliplatin arm, with 4.77 months of TTF and 11.37 months of OS in the control arm; there was no significance between the 2 arms (p>0.05). Oxaliplatin reexposure resulted in 6.3% objective response rate with no complete response, 6 partial response, 39 stable disease, and 37 progressive disease. The disease control rate was 47.4% (45/95). The multivariate analysis found that patients who achieved disease control by oxaliplatin reexposure had a superior TTF (6.13 vs 1.7 months, p<0.001) and OS (15.73 vs 6.27 months, p<0.001) compared with those presenting with progressive disease.

Conclusion

This study showed that rechallenge of oxaliplatin-containing chemotherapy in the third- or later-line therapy may lead to tumor control and improved survival in mCRC patients, which was equivalent to that of anti-EGFR antibodies with irinotecan.

Clinical significance

Rechallenge of oxaliplatin-containing regimens in the third- or later-line of therapy is a common practice, despite few evidence available. The present study found that rechallenge of oxaliplatin-containing regimens produced equivalent tumor control and survival benefit to that of anti-EGFR antibodies with irinotecan in mCRC.

A Prospective Study of Chronic Oxaliplatin-Induced Neuropathy in Patients with Colon Cancer: Long-Term Outcomes and Predictors of Severe Oxaliplatin-Induced Neuropathy

Background and Purpose

The objective of this study was to determine the incidence and long-term outcomes of oxaliplatin-induced peripheral neuropathy (OIPN), as well as predictors of its severe form.

Methods

Sixty-nine patients who were taking oxaliplatin for colon cancer were prospectively followed prior to starting chemotherapy and after 4, 8, and 12 cycles of chemotherapy. Thirty-six patients completed the follow-up at 1 year after the end of chemotherapy. The patients were assessed using clinical assessment scales and nerve conduction studies (NCS) at each follow-up visit.

Results

By applying the National Cancer Institute Common Toxicity criteria, OIPN was classified as grade 1 in 30 (44%) patients, grade 2 in 25 (36%), and grade 3 in 10 (14%) at the completion of therapy. At 1 year after the treatment, OIPN of grades 1, 2, and 3 was found in 50, 3, and 11% of the patients, respectively. Multivariate analysis showed that reductions of the amplitude of the sensory action potential of >11.5% in the median nerve between baseline and four cycles of chemotherapy (odds ratio=5.603, p=0.031) and of >22.5% in the sural nerve between four and eight cycles of chemotherapy (odds ratio=5.603, p=0.031) were independently associated with the risk of developing grade-3 OIPN.

Conclusions

While the severity of OIPN can improve after oxaliplatin discontinuation, more than half of the patients in this study still had OIPN at 1 year after discontinuation. Early changes in the NCS results for sensory nerves can predict the development of severe OIPN during treatment.

Sigma-1 receptor: a new player in neuroprotection against chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy is a very frequent neurological complication in cancer. Oxaliplatin (OXA) is a platinum analogue used as a first-line agent in the treatment of colorectal cancer. OXA induced peripheral neuropathy (OIN) is the main toxicity both during and after the completion of chemotherapy that presents as two distinct syndromes: acute and chronic neuropathy. None of the neuroprotective agents previously tested had prevented or limited the acute and/or chronic OIN. MR309 (previously developed as E-52862) is a novel selective sigma-1 receptor (S1R) antagonist with preclinical analgesic activity in OXA-induced neuropathic pain in animal models. This review analyzes the results of the recently published phase II, randomized, double-blind, placebo-controlled clinical trial including 124 patients with colorectal cancer (CRC) treated with MR309. This study shows encouraging findings in the setting of neuroprotection against OIN with an acceptable safety profile. The study demonstrated MR309 usefulness in decreasing acute OIN, by reducing cold hypersensitivity experienced by patients, and pointed to the amelioration of chronic OIN by lowering the proportion of patients who developed severe chronic OIN. In addition, we provide a summary and discussion on the pathways that can be modulated by the S1R to explain the observed clinical benefits in the OIN.