Gabapentin Monotherapy for the Treatment of Chemotherapy-Induced Neuropathic Pain: A Pilot Study

KLS-13019, a Novel Structural Analogue of Cannabidiol and GPR55 Receptor Antagonist, Prevents and Reverses Chemotherapy-Induced Peripheral Neuropathy in Rats

Neuropathic pain is a form of chronic pain that develops because of damage to the nervous system. Treatment of neuropathic pain is often incompletely effective, and most available therapeutics have only moderate efficacy and present side effects that limit their use. Opioids are commonly prescribed for the management of neuropathic pain despite equivocal results in clinical studies and significant abuse potential. Thus, neuropathic pain represents an area of critical unmet medical need, and novel classes of therapeutics with improved efficacy and safety profiles are urgently needed. The cannabidiol structural analog and novel antagonist of GPR55, KLS-13019, was screened in rat models of neuropathic pain. Tactile sensitivity associated with chemotherapy exposure was induced in rats with once-daily 1-mg/kg paclitaxel injections for 4 days or 5 mg/kg oxaliplatin every third day for 1 week. Rats were then administered KLS-13019 or comparator drugs on day 7 in an acute dosing paradigm or days 7-10 in a chronic dosing paradigm, and mechanical or cold allodynia was assessed. Allodynia was reversed in a dose-dependent manner in the rats treated with KLS-13019, with the highest dose reverting the response to prepaclitaxel injection baseline levels with both intraperitoneal and oral administration after acute dosing. In the chronic dosing paradigm, four consecutive doses of KLS-13019 completely reversed allodynia for the duration of the phenotype in control animals. Additionally, coadministration of KLS-13019 with paclitaxel prevented the allodynic phenotype from developing. Together, these data suggest that KLS-13019 represents a potential new drug for the treatment of neuropathic pain. SIGNIFICANCE STATEMENT: Chemotherapy-induced peripheral neuropathy (CIPN) is a common, debilitating side effect of cancer treatment with no known cure. The GPR55 antagonist KLS-13019 represents a novel class of drug for this condition that is a potent, durable inhibitor of allodynia associated with CIPN in rats in both prevention and reversal-dosing paradigms. This novel therapeutic approach addresses a critical area of unmet medical need.

HDAC inhibitors as a potential therapy for chemotherapy-induced neuropathic pain

Cancer, a chronic disease characterized by uncontrolled cell development, kills millions of people globally. The WHO reported over 10 million cancer deaths in 2020. Anticancer medications destroy healthy and malignant cells. Cancer treatment induces neuropathy. Anticancer drugs cause harm to spinal cord, brain, and peripheral nerve somatosensory neurons, causing chemotherapy-induced neuropathic pain. The chemotherapy-induced mechanisms underlying neuropathic pain are not fully understood. However, neuroinflammation has been identified as one of the various pathways associated with the onset of chemotherapy-induced neuropathic pain. The neuroinflammatory processes may exhibit varying characteristics based on the specific type of anticancer treatment delivered. Neuroinflammatory characteristics have been observed in the spinal cord, where microglia and astrocytes have a significant impact on the development of chemotherapy-induced peripheral neuropathy. The patient's quality of life might be affected by sensory deprivation, loss of consciousness, paralysis, and severe disability. High cancer rates and ineffective treatments are associated with this disease. Recently, histone deacetylases have become a novel treatment target for chemotherapy-induced neuropathic pain. Chemotherapy-induced neuropathic pain may be treated with histone deacetylase inhibitors. Histone deacetylase inhibitors may be a promising therapeutic treatment for chemotherapy-induced neuropathic pain. Common chemotherapeutic drugs, mechanisms, therapeutic treatments for neuropathic pain, and histone deacetylase and its inhibitors in chemotherapy-induced neuropathic pain are covered in this paper. We propose that histone deacetylase inhibitors may treat several aspects of chemotherapy-induced neuropathic pain, and identifying these inhibitors as potentially unique treatments is crucial to the development of various chemotherapeutic combination treatments.

The impact of scrambler therapy on pain and quality of life for chemotherapy-induced peripheral neuropathy: A pilot study

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating disturbance among patients who received chemotherapy, with no effective treatment available. Scrambler therapy (ST) is a noninvasive treatment capable of improving multiple quality-of-life symptoms beyond pain. We aimed to evaluate the efficacy of ST for pain and nonpain symptoms related to CIPN.

METHODS

Ten patients with moderate to severe CIPN symptoms for >3 months were enrolled in a single-arm trial of ST for 10 daily sessions. CIPN-related symptoms were measured throughout the treatment period and up to 6 months thereafter.

RESULTS

The worst pain was reduced by 6 months (p = 0.0039). QST demonstrated the greatest improvement in pressure of 60 g (p = 0.308, Cohen's d = 0.42) and cold temperature threshold of 2.5°C (p = 0.9375, Cohen's d = 0.51) in the gastrocnemius area. Symptoms of numbness, tingling, trouble walking, and disturbed sleep had significant improvements at 6 months. Pain medication use decreased by 70% at the end of treatment and by 42% at 6 months. Patient satisfaction was high (82%) and no adverse events with ST treatment were reported.

CONCLUSIONS

The results of this pilot trial support the use of ST by demonstrating improvement in multiple domains of quality of life for CIPN patients during an extended follow-up of 6 months. However, further large-scale studies are needed to confirm our findings.

Assessing the effectiveness of gabapentin in paclitaxel-induced arthralgia, myalgia, and neuropathic pain: An observational, cohort study

BACKGROUND AND OBJECTIVES

Arthralgia, myalgia, and neuropathic pain are the most common side effects observed due to paclitaxel chemotherapy. The aim of this study was to investigate the prophylactic role, maintenance, remission, and re-occurrence of arthralgia, myalgia, and neuropathic pain post-gabapentin therapy.

METHODOLOGY

This study was conducted in the Department of Oncology, Dhiraj Hospital, Vadodara with a sample of 51 patients. Newly detected cancer patients who observed arthralgia, myalgia, and neuropathic pain due to paclitaxel were taken and a baseline pain assessment was done using the Common Terminology Criteria for Adverse Events (CTCAE) and painDETECT questionnaire. Gabapentin was given in the first cycle after symptoms appeared and prophylactic treatment was given in the subsequent three cycles and evaluation of pain was done post-gabapentin therapy to assess the symptomatic as well as prophylactic effect.

RESULTS

At baseline, neuropathic pain score was 22.7 ± 3.6 which reduced to 0.01 ± 0.14 on subsequent follow-ups. Grade 2 arthralgia, myalgia, and neuropathic pain were more observed at baseline which reduces to Grade 0 in the third cycle. The difference in baseline and post-gabapentin therapy was statistically analyzed by conducting t-test which showed p-value <0.00001 and t-value was less than -2 which indicated a statistically significant result.

CONCLUSION

This study shows that gabapentin reduces neuropathic pain. Prophylactic usage of gabapentin was highly effective at bringing about quick pain relief when compared to symptomatic treatment. In further follow-ups, it was noted that gabapentin maintained the impact throughout the cycles.

Evaluation of Chemotherapy Induced Peripheral Neuropathy, Sarcopenia and Fatigue in Children with Acute Lymphoblastic Leukaemia and Lymphoma in Tertiary Care Hospital, Dakshina Kannada

Objectives

The study aims to assess the proportion and magnitude of chemotherapy-induced peripheral neuropathy (CIPN) and other common complications reported in children with acute lymphoblastic leukaemia (ALL)/ acute lymphoblastic lymphoma (LBL) undergoing chemotherapy.

Material and Methods

The study included children between 5 and 18 years old with ALL/LBL undergoing chemotherapy in Tertiary Care Hospitals, Mangalore. The study was conducted using various instruments, including paediatric-modified total neuropathy scale for CIPN, handheld dynamometer for muscle strength, bioimpedance analyser for muscle mass, timed up-and-go test for physical performance, and national comprehensive cancer network (NCCN) guidelines for scoring cancer-related fatigue at 3-time points. The collected data were analysed by IBM Statistical Package for the Social Sciences version 29 using Z-scores with standard deviation for distinct ALL/LBL types. In addition, the Paired t-test compared the baseline outcome to the 3rd and 6th time points.

Results

The study evaluated 25 children with ALL undergoing chemotherapy based on the UKALL 2003 protocol during their maintenance phase. The study found that 25 children experienced CIPN, with changes in sensory and pin sensibility scores at 3 and 6 months. The study found a significant change in handgrip strength, body mass index, and muscle mass at 3 months, with no significant change in physical performance over time. Fatigue scores increased from baseline to 3 months, with significant changes observed for the 7-12 years age group at 3 months but not for the 5-6 years age group at 6 months.

Conclusion

Children with ALL/LBL undergoing chemotherapy experience CIPN and other side effects such as sarcopenia and fatigue. The study highlights the potential benefits of physiotherapy interventions and supportive care strategies aimed at managing the adverse effects of chemotherapy in children with ALL/LBL.

Evidence-Based Treatment of Pain in Chemotherapy-Induced Peripheral Neuropathy

PURPOSE OF REVIEW

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and often painful condition that occurs after administration of chemotherapeutic agents. The primary objective of this systematic review was to appraise the literature on conservative, pharmacological, and interventional treatment options for CIPN pain.

RECENT FINDINGS

There is level I evidence supporting modest to moderate improvement in CIPN pain from duloxetine treatment, as well as short-term modest improvement from physical therapy and acupuncture. Although opioid and cannabis administration may provide short-term modest improvement, administration is commonly limited by side effects. Generally, most studies reported no clinical benefit from yoga, topical neuropathic agents, gabapentinoids, and tricyclic antidepressants. Evidence is currently equivocal for scrambler therapy and transcutaneous electrical nerve stimulation. Finally, evidence on neuromodulation options is limited to mostly case reports/series and one observational study highlighting moderate improvement with auricular nerve stimulation. This systematic review provides an overview of conservative, pharmacologic, and interventional treatment modalities for CIPN pain. Furthermore, it provides a level of evidence and degree of recommendation based on the United States Preventive Services Task Force (USPSTF) criteria for each specific treatment modality.

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

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

Metabolite profiling reveals a connection between aldehyde dehydrogenase 1A3 and GABA metabolism in breast cancer metastasis

INTRODUCTION

Aldehyde dehydrogenase 1A3 (ALDH1A3) is a cancer stem cell (CSC) marker and in breast cancer it is associated with triple-negative/basal-like subtypes and aggressive disease. Studies on the mechanisms of ALDH1A3 in cancer have primarily focused on gene expression changes induced by the enzyme; however, its effects on metabolism have thus far been unstudied and may reveal novel mechanisms of pathogenesis.

OBJECTIVE

Determine how ALDH1A3 alters the metabolite profile in breast cancer cells and assess potential impacts.

METHOD

Triple-negative MDA-MB-231 tumors and cells with manipulated ALDH1A3 levels were assessed by HPLC-MS metabolomics and metabolite data was integrated with transcriptome data. Mice harboring MDA-MB-231 tumors with or without altered ALDH1A3 expression were treated with γ-aminobutyric acid (GABA) or placebo. Effects on tumor growth, and lungs and brain metastasis were quantified by staining of fixed thin sections and quantitative PCR. Breast cancer patient datasets from TCGA, METABRIC and GEO were used to assess the co-expression of GABA pathway genes with ALDH1A3.

RESULTS

Integrated metabolomic and transcriptome data identified GABA metabolism as a primary dysregulated pathway in ALDH1A3 expressing breast tumors. Both ALDH1A3 and GABA treatment enhanced metastasis. Patient dataset analyses revealed expression association between ALDH1A3 and GABA pathway genes and corresponding increased risk of metastasis.

CONCLUSION

This study revealed a novel pathway affected by ALDH1A3, GABA metabolism. Like ALDH1A3 expression, GABA treatment promotes metastasis. Given the clinical use of GABA mimics to relieve chemotherapy-induced peripheral nerve pain, further study of the effects of GABA in breast cancer progression is warranted.

Pharmacogenetics of Addiction Therapy

Drug addiction is a serious relapsing disease that has high costs to society and to the individual addicts. Treatment of these addictions is still in its nascency, with only a few examples of successful therapies. Therapeutic response depends upon genetic, biological, social, and environmental components. A role for genetic makeup in the response to treatment has been shown for several addiction pharmacotherapies with response to treatment based on individual genetic makeup. In this chapter, we will discuss the role of genetics in pharmacotherapies, specifically for cocaine, alcohol, and opioid dependences. The continued elucidation of the role of genetics should aid in the development of new treatments and increase the efficacy of existing treatments.

High-Dose Gabapentin and Amitriptyline in the Treatment of Refractory Chemotherapy-Induced Peripheral Neuropathy in a Toddler

Pharmacologic management of chemotherapy-induced peripheral neuropathy (CIPN) in pediatric patients remains a challenge. Without effective treatment to control pain from CIPN in children, reduction or discontinuation of life-saving chemotherapeutic medications may be required. Various combinations of medications are available, but none have been thoroughly evaluated for their effectiveness in managing CIPN in the pediatric population. We present the clinical management of severe CIPN in a 3-year-old child with pre-B acute lymphoblastic lymphoma that was refractory to a regiment that included high-dose gabapentin and opioids. Therapy was subsequently adjusted to include amitriptyline, eliminating the need for opioids with complete resolution of symptoms. The potential combination pharmacotherapies for pediatric CIPN are discussed and mechanisms accounting for inadequate response with monotherapy are presented.

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.

Effect of hyperbaric oxygen on chemotherapy-induced neuropathy in male and female rats

Chemotherapeutic agents can cause peripheral neuropathy, a deleterious side effect of cancer treatment. Hyperbaric oxygen (HBO2) treatment has shown great potential for decreasing pain in numerous clinical pain conditions and in preclinical studies. This study was designed to test whether HBO2 might also be useful for treating chemotherapy-induced peripheral neuropathy. Male and female Sprague-Dawley rats were injected with 1 mg/kg paclitaxel or vehicle every other day for 7 days to induce allodynia, followed by either one single, or four daily 60-min exposures to HBO2 or room air. Mechanical and cold allodynia as well as locomotor behavior and body weight were assessed intermittently for several weeks. Estrous cycling was also tracked in female rats. Paclitaxel caused pronounced mechanical allodynia in both sexes that was completely reversed by either one or four treatments of HBO2. Females in all treatment groups showed greater cold acetone scores than males, and acetone scores were not reliably reduced by HBO2 treatment. Neither paclitaxel nor HBO2 treatment altered locomotor behavior or estrous cycling. We conclude that HBO2 treatment was highly effective at reducing mechanical allodynia in paclitaxel-treated rats without affecting weight gain, locomotion, or estrous cycling, suggesting that HBO2 may be effective for treating chemotherapy-induced neuropathic pain without producing significant side effects.

Effects of Nonpharmacological Interventions in Chemotherapy-Induced Peripheral Neuropathy: An Overview of Systematic Reviews and Meta-Analyses

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the prevalent and disabling side effects of cancer treatment. However, management strategies for CIPN currently remain elusive, with treatment restricted to neuropathic pain medications, supportive care, and chemotherapy dosing adjustments. This overview explores evidence on the potential benefits and safety of nonpharmacological interventions in preventing and treating CIPN in cancer patients.

METHODS

Seven databases were searched for systematic reviews of randomized controlled trials (RCTs). The methodological quality of the selected reviews was assessed by AMSTAR 2, and the quality of evidence was judged by GRADE. Twenty-eight systematic reviews were considered eligible for this review.

RESULTS

It was found that nonpharmacological interventions (acupuncture, exercise, herbal medicine, nutritional supplements) provided potential benefits for patients with CIPN. Furthermore, Chinese herbal medicine, administered orally or externally, significantly prevented and/or relieved the incidence and severity of CIPN in comparison to control groups (no additional treatment, placebo, and conventional western medicine). However, the quality of evidence and strength of recommendations were compromised by the inconsistencies and imprecision of included studies. The main concerns regarding the quality of systematic reviews included the lack of sufficiently rigorous a priori protocols, and the lack of protocol registration adopted in the included studies.

CONCLUSIONS

Though looking across reviews, Chinese herbal medicine appear generally effective in CIPN, uncertainty remains about the effects of many other nonpharmacological interventions. The evidence on what works was particularly compromised by reporting and methodological limitations, which requires further investigation to be more certain of their effects.

Management of Peripheral Neuropathy Induced by Chemotherapy

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is considered a severe side effect of therapeutic agents with limited treatment options. The incidence of CIPN in cancer patients is approximately 3-7% in cytostatic monotherapy and as high as 38% in cases of polychemotherapy. The prevalence of CIPN was found to be 68% within the first month of chemotherapy treatment. In some cases, CIPN can resolve, partially or completely, after completion of the treatment; in other cases, it can remain for a long time and affect the patient's quality of life.

OBJECTIVE

The aim of this study is to present up-to-date data regarding available treatment options for the management of CIPN.

MATERIALS AND METHODS

The up-to-date guidelines of ESMO (European Society for Medical Oncology), ASCO (American Society of Clinical Oncology), ONS (Oncology Nursing Society), NCI (National Cancer Institute), and NCCN (National Comprehensive Cancer Network) were reviewed and included in the manuscript.

RESULTS

The use of tricyclic antidepressant (TCA), selective serotonin norepinephrine reuptake inhibitor (SSNRI), pregabalin, and gabapentin are recommended as first-line treatment. Other treatment options were offered as second and third lines of treatment (lidocaine patches, capsaicin high-concentration patches, tramadol, and strong opioids, respectively); however, lower significance was demonstrated. Inconclusive results were found in the use of cannabinoids, drug combinations, antiepileptics, antidepressants, and topical drugs.

CONCLUSION

TCA, other antidepressants, and opioids could be recommended as treatment. Yet, we could not recommend an ideal therapeutic agent for the prevention or treatment of CIPN. Therefore, CIPN continues to be a challenge to clinicians and our patients.

Chemokine Signaling in Chemotherapy-Induced Neuropathic Pain

Chemotherapy-induced peripheral neuropathy (CIPN) is a side effect of chemotherapics such as taxanes, vinca alkaloids, and platinum compounds. In recent years, several reports have indicated the involvement of different molecular mechanisms in CIPN. The pathways described so far are diverse and target various components of the peripheral Nervous System (PNS). Among the contributors to neuropathic pain, inflammation has been indicated as a powerful driver of CIPN. Several pieces of evidence have demonstrated a chemotherapy-induced increase in peripheral pro-inflammatory cytokines and a strong correlation with peripheral neuropathy. At present, there are not adequate strategies to prevent CIPN, although there are drugs for treating CIPN, such as duloxetine, that have displayed a moderate effect on CIPN. In this review, we focus on the players involved in CIPN with a particular emphasis on chemokine signaling.

Increased α2δ-1-NMDA receptor coupling potentiates glutamatergic input to spinal dorsal horn neurons in chemotherapy-induced neuropathic pain

Painful peripheral neuropathy is a severe and difficult-to-treat neurological complication associated with cancer chemotherapy. Although chemotherapeutic drugs such as paclitaxel are known to cause tonic activation of presynaptic NMDA receptors (NMDARs) to potentiate nociceptive input, the molecular mechanism involved in this effect is unclear. α2δ-1, commonly known as a voltage-activated calcium channel subunit, is a newly discovered NMDAR-interacting protein and plays a critical role in NMDAR-mediated synaptic plasticity. Here we show that paclitaxel treatment in rats increases the α2δ-1 expression level in the dorsal root ganglion and spinal cord and the mRNA levels of GluN1, GluN2A, and GluN2B in the spinal cord. Paclitaxel treatment also potentiates the α2δ-1-NMDAR interaction and synaptic trafficking in the spinal cord. Strikingly, inhibiting α2δ-1 trafficking with pregabalin, disrupting the α2δ-1-NMDAR interaction with an α2δ-1 C-terminus-interfering peptide, or α2δ-1 genetic ablation fully reverses paclitaxel treatment-induced presynaptic NMDAR-mediated glutamate release from primary afferent terminals to spinal dorsal horn neurons. In addition, intrathecal injection of pregabalin or α2δ-1 C-terminus-interfering peptide and α2δ-1 knockout in mice markedly attenuate paclitaxel-induced pain hypersensitivity. Our findings indicate that α2δ-1 is required for paclitaxel-induced tonic activation of presynaptic NMDARs at the spinal cord level. Targeting α2δ-1-bound NMDARs, not the physiological α2δ-1-free NMDARs, may be a new strategy for treating chemotherapy-induced neuropathic pain. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.

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.

Cancer-Related Neuropathic Pain: Review and Selective Topics

Neuropathic pain is the result of neuroplastic and neuroinflammatory changes from trauma or diseases that damage the somatosensory system. Cancer-related neuropathic pain is caused by treatment, cancer, or paraneoplastic reactions to cancer. Approximately 30% of patients with cancer have neuropathic pain, mostly mixed nociceptive and neuropathic pain. History, physical examination, quantitative sensory testing, skin punch biopsies, and functional MRIs help to divide pain into phenotypes that may facilitate analgesic choices. Guidelines for treating cancer-related neuropathic pain are not consistent and are highly dependent on trials in patients without cancer. Combinations of analgesics are promising, whereas evidence for cannabinoids is meager.

Beyond symptomatic relief for chemotherapy-induced peripheral neuropathy: Targeting the source

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious adverse side effect of many chemotherapeutic agents, affecting >60% of patients with cancer. Moreover, CIPN persists long into survivorship in approximately 20% to 30% of these patients. To the authors' knowledge, no drugs have been approved to date by the US Food and Drug Administration to effectively manage chemotherapy-induced neuropathic pain. The majority of the drugs tested for the management of CIPN aim at symptom relief, including pain and paresthesia, yet are not very efficacious. The authors propose that there is a need to acquire a more thorough understanding of the etiology of CIPN so that effective, mechanism-based, disease-modifying interventions can be developed. It is important to note that such interventions should not interfere with the antitumor effects of chemotherapy. Mitochondria are rod-shaped cellular organelles that represent the powerhouses of the cell, in that they convert oxygen and nutrients into the cellular energy "currency" adenosine triphosphate. In addition, mitochondria regulate cell death. Neuronal mitochondrial dysfunction and the associated nitro-oxidative stress represent crucial final common pathways of CIPN. Herein, the authors discuss the potential to prevent or reverse CIPN by protecting mitochondria and/or inhibiting nitro-oxidative stress with novel potential drugs, including the mitochondrial protectant pifithrin-μ, histone deacetylase 6 inhibitors, metformin, antioxidants, peroxynitrite decomposition catalysts, and anti-inflammatory mediators including interleukin 10. This review hopefully will contribute toward bridging the gap between preclinical research and the development of realistic novel therapeutic strategies to prevent or reverse the devastating neurotoxic effects of chemotherapy on the (peripheral) nervous system. Cancer 2018;124:2289-98. © 2018 American Cancer Society.

Pain in Platin-Induced Neuropathies: A Systematic Review and Meta-Analysis

Introduction

Platin-induced peripheral neuropathy (PIPN) is a common cause of PN in cancer patients. The aim of this paper is to systematically review the current literature regarding PIPN, with a particular focus on epidemiological and clinical characteristics of painful PIPN, and to discuss relevant management strategies.

Methods

A systematic computer-based literature search was conducted on the PubMed database.

Results

This search strategy resulted in the identification of 353 articles. After the eligibility assessment, 282 articles were excluded. An additional 24 papers were identified by scanning the reference lists. In total, 95 papers met the inclusion criteria and were used for this review. The prevalence of neuropathic symptoms due to acute toxicity of oxaliplatin was estimated at 84.6%, whereas PN established after chemotherapy with platins was estimated at 74.9%. Specifically regarding pain, the reported prevalence of pain due to acute toxicity of oxaliplatin was estimated at 55.6%, whereas the reported prevalence of chronic peripheral neuropathic pain in PIPN was estimated at 49.2%.

Conclusion

Peripheral neuropathy is a common complication in patients receiving platins and can be particularly painful. There is significant heterogeneity among studies regarding the method for diagnosing peripheral neuropathy. Nerve conduction studies are the gold standard and should be performed in patients receiving platins and complaining of neuropathic symptoms post-treatment.

The efficacy of combination treatment of gabapentin and electro-acupuncture on paclitaxel-induced neuropathic pain

Paclitaxel, a chemotherapeutic drug, induces severe peripheral neuropathy. Gabapentin (GBT) is a first line agent used to treat neuropathic pain, and its effect is mediated by spinal noradrenergic and muscarinic cholinergic receptors. Electro-acupuncture (EA) is used for treating various types of pain via its action through spinal opioidergic and noradrenergic receptors. Here, we investigated whether combined treatment of these two agents could exert a synergistic effect on paclitaxel-induced cold and mechanical allodynia, which were assessed by the acetone drop test and von Frey filament assay, respectively. Significant signs of allodynia were observed after four paclitaxel injections (a cumulative dose of 8 mg/kg, i.p.). GBT (3, 30, and 100 mg/kg, i.p.) or EA (ST36, Zusanli) alone produced dose-dependent anti-allodynic effects. The medium and highest doses of GBT (30 and 100 mg/kg) provided a strong analgesic effect, but they induced motor dysfunction in Rota-rod tests. On the contrary, the lowest dose of GBT (3 mg/kg) did not induce motor weakness, but it provided a brief analgesic effect. The combination of the lowest dose of GBT and EA resulted in a greater and longer effect, without inducing motor dysfunction. This effect on mechanical allodynia was blocked by spinal opioidergic (naloxone, 20 μg), or noradrenergic (idazoxan, 10 μg) receptor antagonist, whereas on cold allodynia, only opioidergic receptor antagonist blocked the effect. In conclusion, the combination of the lowest dose of GBT and EA has a robust and enduring analgesic action against paclitaxel-induced neuropathic pain, and it should be considered as an alternative treatment method.

Informative gene network for chemotherapy-induced peripheral neuropathy

BACKGROUND

Host genetic variability has been implicated in chemotherapy-induced peripheral neuropathy (CIPN). A dose-limiting toxicity for chemotherapy agents, CIPN is also a debilitating condition that may progress to chronic neuropathic pain. We utilized a bioinformatics approach, which captures the complexity of intracellular and intercellular interactions, to identify genes for CIPN.

METHODS

Using genes pooled from the literature as a starting point, we used Ingenuity Pathway Analysis (IPA) to generate gene networks for CIPN.

RESULTS

We performed IPA core analysis for genes associated with platinum-, taxane- and platinum-taxane-induced neuropathy. We found that IL6, TNF, CXCL8, IL1B and ERK1/2 were the top genes in terms of the number of connections in platinum-induced neuropathy and TP53, MYC, PARP1, P38 MAPK and TNF for combined taxane-platinum-induced neuropathy.

CONCLUSION

Neurotoxicity is common in cancer patients treated with platinum compounds and anti-microtubule agents and CIPN is one of the debilitating sequela. The bioinformatic approach helped identify genes associated with CIPN in cancer patients.

Therapeutic strategies for cancer treatment related peripheral neuropathies

OPINION STATEMENT

Chemotherapy-induced peripheral neuropathy (CIPN) is a common toxicity associated with multiple chemotherapeutic agents. CIPN may have a detrimental impact on patients' quality of life and functional ability, as well as result in chemotherapy dose reductions. Although symptoms of CIPN can improve with treatment completion, symptoms may persist. Currently, the treatment options for CIPN are quite limited. Duloxetine, a serotonin-norepinephrine reuptake inhibitor, has the most evidence supporting its use in the treatment of CIPN. Other agents with potential benefit for the treatment of established CIPN include gabapentinoids, venlafaxine, tricyclic antidepressants, and a topical gel consisting of the combination of amitriptyline, ketamine, and baclofen; none of these, however, has been proven to be helpful and ongoing/future studies may well show that they are not beneficial. The use of these agents is often based on their efficacy in the treatment of non-CIPN neuropathic pain, but this does not necessarily mean that they will be helpful for CIPN-related symptoms. Other nonpharmacologic interventions including acupuncture and Scrambler therapy are supported by positive preliminary data; however, further larger, placebo-controlled trial data are needed to confirm or refute their effectiveness.

Current use of drugs affecting the central nervous system for chemotherapy-induced peripheral neuropathy in cancer patients: a systematic review

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is common among cancer patients who undergo chemotherapy with platinum analogues, taxanes, vinca alkaloids, epothilone, bortezomib, and thalidomide. The purpose of this study was to investigate the evidence of using drugs affecting the central nervous system (CNS) to alleviate CIPN in cancer patients.

METHODS

A systematic literature search was conducted using the CINAHL, EMBASE, and Medline databases to identify randomized controlled clinical trials (RCTs) reported in English up to 2013. We identified ten trials of CNS-acting drugs used to treat CIPN in cancer patients and reviewed efficacy and safety of CNS-acting drugs for CIPN using a standard data collection form. The risk of bias in each RCT was also assessed.

RESULTS

Antidepressants were used in six studies and anticonvulsants in four studies. We found positive results for amitriptyline (topical), venlafaxine, and oxcarbazepine in one study each, but the results were not sufficient to draw definite conclusions. One trial with duloxetine showed a moderate effect (effect size, 0.513, P = .003) on CIPN pain relief. However, none of the results has yet been duplicated in an RCT with a large sample size.

CONCLUSIONS

Insufficient RCTs exist to confirm the efficacy of CNS agents to reduce CIPN. This study highlighted the need for and the importance of conducting well-designed RCTs to generate evidence on CIPN symptom management. Additional RCTs are warranted to accelerate the potential use of CNS drugs for CIPN in cancer patients.

Management options for established chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating condition associated with a variety of chemotherapeutic agents. Clinicians are cognizant of the negative impact of CIPN on cancer treatment outcomes and patients' psychosocial functioning and quality of life. In an attempt to alleviate this problem, clinicians and patients try various therapeutic interventions, despite limited evidence to support efficacy of these treatments. The rationale for such use is mostly based on the evidence for the treatment options in non-CIPN peripheral neuropathy syndromes, as this area is more robustly studied than is CIPN treatment. In this manuscript, we examine the existing evidence for both CIPN and non-CIPN treatments and develop a summary of the best available evidence with the aim of developing a practical approach to the treatment of CIPN, based on available literature and clinical practice experience.

Neuropathic cancer pain: What we are dealing with? How to manage it?

Cancer pain is a serious health problem, and imposes a great burden on the lives of patients and their families. Pain can be associated with delay in treatment, denial of treatment, or failure of treatment. If the pain is not treated properly it may impair the quality of life. Neuropathic cancer pain (NCP) is one of the most complex phenomena among cancer pain syndromes. NCP may result from direct damage to nerves due to acute diagnostic/therapeutic interventions. Chronic NCP is the result of treatment complications or malignancy itself. Although the reason for pain is different in NCP and noncancer neuropathic pain, the pathophysiologic mechanisms are similar. Data regarding neuropathic pain are primarily obtained from neuropathic pain studies. Evidence pertaining to NCP is limited. NCP due to chemotherapeutic toxicity is a major problem for physicians. In the past two decades, there have been efforts to standardize NCP treatment in order to provide better medical service. Opioids are the mainstay of cancer pain treatment; however, a new group of therapeutics called coanalgesic drugs has been introduced to pain treatment. These coanalgesics include gabapentinoids (gabapentin, pregabalin), antidepressants (tricyclic antidepressants, duloxetine, and venlafaxine), corticosteroids, bisphosphonates, N-methyl-D-aspartate antagonists, and cannabinoids. Pain can be encountered throughout every step of cancer treatment, and thus all practicing oncologists must be capable of assessing pain, know the possible underlying pathophysiology, and manage it appropriately. The purpose of this review is to discuss neuropathic pain and NCP in detail, the relevance of this topic, clinical features, possible pathology, and treatments of NCP.

The anticonvulsant enaminone E139 attenuates paclitaxel-induced neuropathic pain in rodents

The enaminone methyl 4-(4′-bromophenyl)aminocyclohex-3-en-6-methyl-2-oxo-1-oate (E139) has anticonvulsant activities. It has been reported to have a better safety profile than some anticonvulsant drugs. Since some anticonvulsant drugs are used in the management of neuropathic pain, we evaluated the effects of E139 in rodent models of acute pain and paclitaxel-induced neuropathic pain. The reaction latency to thermal stimuli (hot-plate test) of BALB/c mice was recorded before and after intraperitoneal treatment with paclitaxel (2 mg/kg, i.p. for 5 consecutive days), and after treatment with E139 (0.1–40 mg/kg), amitriptyline (10 mg/kg), and gabapentin (10 and 30 mg/kg). Mechanical allodynia in paclitaxel-treated Sprague Dawley (SD) rats was measured using a dynamic plantar aesthesiometer before and after treatment with E139 (10 and 20 mg/kg) or its vehicle for four consecutive days from day 7 after first administration of paclitaxel (16 mg/kg on two alternate days). Administration of E139 (10–40 mg/kg) produced antinociceptive activity against thermal nociception in naïve mice. Treatment with E139, amitriptyline, or gabapentin reduced paclitaxel-induced thermal hyperalgesia. E139 reduced paclitaxel-induced mechanical allodynia, with the effects lasting longer (24 h) after repetitive dosing. Our results indicate that E139 has antinociceptive activity and attenuates paclitaxel-induced neuropathic pain in rodents.

Chemotherapy-induced peripheral neuropathy: an algorithm to guide nursing management

Oncology nurses play a critical role in the assessment and management of chemotherapy-induced peripheral neuropathy (CIPN). Baseline and ongoing evaluation of physical function is a critical but often overlooked aspect of assessment of CIPN. The diversity of symptoms and the complexity associated with neuromuscular assessment lead to challenges in evaluation and management of CIPN. To meet this challenge, the authors devised a feasible algorithm to guide oncology nurses in the assessment and management of CIPN using techniques that can easily be implemented in a variety of clinical settings. Managing pain, maintaining safety, and maximizing physical function are the primary goals for nursing management of CIPN.

The evidence for pharmacologic treatment of neuropathic cancer pain: beneficial and adverse effects

CONTEXT

The prevalence of neuropathic pain in patients with cancer pain has been estimated to be around 40%. Neuropathic pain may be caused by tumor invasion and is considered as mixed nociceptive-neuropathic pain, or caused by an anticancer treatment and considered as purely neuropathic pain. The use of adjuvant analgesics in patients with cancer is usually extrapolated from their efficacy in nononcological neuropathic pain syndromes.

OBJECTIVES

In this systematic review, we sought to evaluate the evidence for the beneficial and adverse effects of pharmacologic treatment of neuropathic cancer pain.

METHODS

A systematic review of the literature in PubMed and Embase was performed. Primary outcome measures were absolute risk benefit (ARB), defined as the number of patients with a defined degree of pain relief divided by the total number of patients in the treatment group, and absolute risk harm (ARH), defined as the fraction of patients who dropped out as a result of adverse effects.

RESULTS

We identified 30 articles that fulfilled our inclusion criteria. Overall, ARB of antidepressants, anticonvulsants, other adjuvant analgesics, or opioids greatly outweighed ARH. There were no significant differences in ARB or ARH between the four groups of medication or between patients with mixed vs. purely neuropathic pain. Because of the low methodological quality of the studies, we could not draw conclusions about the true treatment effect size of the four groups of medications.

CONCLUSION

Once a diagnosis of neuropathic pain has been established in patients with cancer, antidepressants, anticonvulsants, or other adjuvant analgesics should be considered in addition to or instead of opioids.

Implications and mechanism of action of gabapentin in neuropathic pain

Gabapentin is an anti-epileptic agent but now it is also recommended as first line agent in neuropathic pain, particularly in diabetic neuropathy and post herpetic neuralgia. α2δ-1, an auxillary subunit of voltage gated calcium channels, has been documented as its main target and its specific binding to this subunit is described to produce different actions responsible for pain attenuation. The binding to α2δ-1 subunits inhibits nerve injury-induced trafficking of α1 pore forming units of calcium channels (particularly N-type) from cytoplasm to plasma membrane (membrane trafficking) of pre-synaptic terminals of dorsal root ganglion (DRG) neurons and dorsal horn neurons. Furthermore, the axoplasmic transport of α2δ-1 subunits from DRG to dorsal horns neurons in the form of anterograde trafficking is also inhibited in response to gabapentin administration. Gabapentin has also been shown to induce modulate other targets including transient receptor potential channels, NMDA receptors, protein kinase C and inflammatory cytokines. It may also act on supra-spinal region to stimulate noradrenaline mediated descending inhibition, which contributes to its anti-hypersensitivity action in neuropathic pain.

Pharmacological treatment of neuropathic cancer pain: a comprehensive review of the current literature

Neuropathic cancer pain (NCP), commonly encountered in clinical practice, may be cancer-related, namely resulting from nervous system tumor invasion, surgical nerve damage during tumor removal, radiation-induced nerve damage and chemotherapy-related neuropathy, or may be of benign origin, unrelated to cancer. A neuropathic component is evident in about 1/3 of cancer pain cases. Although from a pathophysiological perspective NCP may differ from chronic neuropathic pain (NP), such as noncancer-related pain, clinical practice, and limited publications have shown that these two pain entities may share some treatment modalities. For example, co-analgesics have been well integrated into cancer pain-management strategies and are often used as First-Line options for the treatment of NCP. These drugs, including antidepressants and anticonvulsants, are recommended by evidence-based guidelines, whereas, others such as lidocaine patch 5%, are supported by randomized, controlled, clinical data and are included in guidelines for restricted conditions treatment. The vast majority of these drugs have already been proven useful in the management of benign NP syndromes. Treatment decisions for patients with NP can be difficult. The intrinsic difficulties in performing randomized controlled trials in cancer pain have traditionally justified the acceptance of drugs already known to be effective in benign NP for the management of malignant NP, despite the lack of relevant high quality data. Interest in NCP mechanisms and pharmacotherapy has increased, resulting in significant mechanism-based treatment advances for the future. In this comprehensive review, we present the latest knowledge regarding NCP pharmacological management.

Neurotoxicity caused by the treatment with platinum analogues

Platinum agents (cisplatin, carboplatin, and oxaliplatin) are a class of chemotherapy agents that have a broad spectrum of activity against several solid tumors. Toxicity to the peripheral nervous system is the major dose-limiting toxicity of at least some of the platinum drugs of clinical interest. Among the platinum compounds in clinical use, cisplatin is the most neurotoxic, inducing mainly sensory neuropathy of the upper and lower extremities. Carboplatin is generally considered to be less neurotoxic than cisplatin, but it is associated with a higher risk of neurological dysfunction if administered at high dose or in combination with agents considered to be neurotoxic. Oxaliplatin induces two types of peripheral neuropathy, acute and chronic. The incidence of oxaliplatin-induced neuropathy is related to various risk factors such as treatment schedule, cumulative dose, and time of infusion. To date, several neuroprotective agents including thiol compounds, vitamin E, various anticonvulsants, calcium-magnesium infusions, and other nonpharmacological strategies have been tested for their ability to prevent platinum-induced neurotoxicity with controversial results. Further studies on the prevention and treatment of neurotoxicity of platinum analogues are warranted.

Chemotherapy-induced neuropathic pain

PURPOSE OF REVIEW

To discuss the importance, clinical features, possible pathology and treatments of chemotherapy-induced neuropathic pain. Newer biological agents such as bortezomib will be considered in greater detail.

RECENT FINDINGS

Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent complication of common anticancer therapies. It may lead to treatment compromise, significantly adds to the symptom burden and interferes with quality of life of cancer survivors. Recent investigations have identified processes involved in CIPN which may give some insight for the development of novel treatments. CIPN induced by different anticancer therapies may be heterogeneous and present as distinct neuropathic pains. Recent work has focussed on the newer anticancer drugs such as bortezomib. Contemporaneous studies have failed to find good evidence for the use of several common antineuropathic agents and further research is required.

SUMMARY

Painful CIPN remains under recognized and undertreated. It is an important cause of pain during cancer treatment and is a common pain in the cancer survivor. Difficulties in assessment and limitations in treatment contribute to management problems. Improvements in education (patient and clinician), assessment and treatment would potentially reduce the often debilitating effects of painful CIPN.

Monoclonal gammopathy of undetermined significance: a consensus statement

On February 25, 2009, a panel of international experts on plasma cell dyscrasia and skeletal disease met to discuss monoclonal gammopathy of undetermined significance (MGUS). This non-malignant B-cell disorder is the most common plasma cell dyscrasia and is associated with an increased risk of developing serious B-cell disorders. Individuals with MGUS also have an increased risk of osteoporosis and osteopenia associated with an increased likelihood of developing fractures especially in the vertebral column, peripheral neuropathy and thromboembolic events. The goal of the meeting was to develop a consensus statement regarding the appropriate tests to screen, evaluate and follow-up patients with MGUS. The panel also addressed the identification and treatment of MGUS-related skeletal problems, thromboembolic events and neurological complications. The following consensus statement outlines the conclusions and marks the first time that a consensus statement for the screening and treatment of MGUS has been clearly stated.

Chemotherapy-induced peripheral neuropathy as a predictor of neuropathic pain in breast cancer patients previously treated with paclitaxel

Neuropathic pain (NP) remains difficult to control for a significant number of patients with cancer. Chemotherapy-induced peripheral neuropathy (CIPN) has been postulated as an initial stage in the development of NP. To assess whether CIPN (defined as National Cancer Institute Common Toxicity Criteria grade 2 or higher) was associated with NP, we conducted a survey of breast cancer patients who had participated in clinical trials of paclitaxel. Of the 430 potential respondents, 240 responded to the survey. Results showed that 64% experienced CIPN during paclitaxel treatment. Follow-up survey data revealed that 27% of those with CIPN were subsequently diagnosed with NP. Logistic regression analyses showed that those who had experienced CIPN were 3 times more likely to develop NP (95% confidence interval = 1.2-7.2; P < .001), which persisted in the multivariate logistic model. In addition, NP patients reported twice as many visits to their health care provider (P = .02) and had taken more prescription (50% vs 19%; P = .001) and over-the-counter medications (62.5% versus 45%; P = .08) for pain than those without NP. The results of this study confirm that CIPN is a predictor of NP, suggesting that survivors treated with paclitaxel should be regularly monitored for NP beyond treatment.

PERSPECTIVE

The survival rates of breast cancer patients have steadily improved over recent years; thus, research into symptoms that persist after treatment is important. We found CIPN as a predictor of NP. Understanding the epidemiology of NP in breast cancer patients has high clinical and public health significance.