Efficacy of lamotrigine in the management of chemotherapy-induced peripheral neuropathy: a phase 3 randomized, double-blind, placebo-controlled trial, N01C3

Chemotherapy-Induced Peripheral Neuropathy: A Recent Update on Pathophysiology and Treatment

Chemotherapy-induced peripheral neuropathy (CIPN) is a major long-lasting side effect of some chemotherapy drugs, which threatens cancer survival rate. CIPN mostly affects sensory neurons and occasionally motor neurons, causing numbness, tingling, discomfort, and burning pain in the upper and lower extremities. The pathophysiology of CIPN is not completely understood; however, it is believed that chemotherapies induce peripheral neuropathy via directly damaging mitochondria, impairing the function of ion channels, triggering immunological mechanisms, and disrupting microtubules. The treatment of CIPN is a medical challenge, and there are no approved pharmacological options. Currently, duloxetine and other antidepressants, antioxidant, anti-inflammatory, and ion-channel targeted therapies are commonly used in clinics to relieve the symptoms of CIPN. Several other types of drugs, such as cannabinoids, sigma-1 receptor antagonists, and nicotinamides ribose, are being evaluated in preclinical and clinical studies. This paper summarizes the information related to the physiology of CIPN and medicines that could be used for treating this condition.

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.

Current understanding of the molecular mechanisms of chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is the most common off-target adverse effects caused by various chemotherapeutic agents, such as cisplatin, oxaliplatin, paclitaxel, vincristine and bortezomib. CIPN is characterized by a substantial loss of primary afferent sensory axonal fibers leading to sensory disturbances in patients. An estimated of 19-85% of patients developed CIPN during the course of chemotherapy. The lack of preventive measures and limited treatment options often require a dose reduction or even early termination of life-saving chemotherapy, impacting treatment efficacy and patient survival. In this Review, we summarized the current understanding on the pathogenesis of CIPN. One prominent change induced by chemotherapeutic agents involves the disruption of neuronal cytoskeletal architecture and axonal transport dynamics largely influenced by the interference of microtubule stability in peripheral neurons. Due to an ineffective blood-nerve barrier in our peripheral nervous system, exposure to some chemotherapeutic agents causes mitochondrial swelling in peripheral nerves, which lead to the opening of mitochondrial permeability transition pore and cytochrome c release resulting in degeneration of primary afferent sensory fibers. The exacerbated nociceptive signaling and pain transmission in CIPN patients is often linked the increased neuronal excitability largely due to the elevated expression of various ion channels in the dorsal root ganglion neurons. Another important contributing factor of CIPN is the neuroinflammation caused by an increased infiltration of immune cells and production of inflammatory cytokines. In the central nervous system, chemotherapeutic agents also induce neuronal hyperexcitability in the spinal dorsal horn and anterior cingulate cortex leading to the development of central sensitization that causes CIPN. Emerging evidence suggests that the change in the composition and diversity of gut microbiota (dysbiosis) could have direct impact on the development and progression of CIPN. Collectively, all these aspects contribute to the pathogenesis of CIPN. Recent advances in RNA-sequencing offer solid platform for in silico drug screening which enable the identification of novel therapeutic agents or repurpose existing drugs to alleviate CIPN, holding immense promises for enhancing the quality of life for cancer patients who undergo chemotherapy and improve their overall treatment outcomes.

Colon Cancer Survivorship in Patients Who Have Received Adjuvant Chemotherapy

The number of colon cancer survivors in the United States is increasing due to improved early detection, better treatments that extend survival, and the growing aging population who are at high risk for cancer. Following initial active treatment, colon cancer survivors experience a wide range of long-term physical, psychological, and socio-economic effects that impact their overall well-being. Healthcare providers caring for survivors need to prioritize not only monitoring for cancer recurrence but also optimizing their overall health through addressing these long-term effects; managing their comorbidities; promoting healthy behaviors (like exercise, nutrition, and weight loss); and screening for a second primary cancer depending on their risk. Personalized survivorship care plans should be formulated clearly outlining the roles of various healthcare providers involved in their care. Our review article focuses on these various aspects of colon cancer survivorship, including surveillance for cancer recurrence specific to those who received adjuvant chemotherapy with curative intent.

Time dependent cisplatin dosing differences on hypoalgesia focusing on oxidative stress

Although cisplatin is a key drug in cancer chemotherapy, it often causes sensory peripheral neuropathy, presenting as allodynia in the early stage and hypoalgesia in the serious stage. Chronotherapy has previously been shown to ameliorate cisplatin-induced peripheral neuropathy that was severe enough to cause hypoalgesia in rats. It also has adverse effects such as renal dysfunction and ototoxicity, which are induced by oxidative stress. Here, we show that oxidative stress causes severe cisplatin-induced peripheral neuropathy, and that differences in oxidative stress occur depending on the dosing time of cisplatin. Cisplatin was administered to rats at 5:00 or 17:00 every seven days for four weeks. The antioxidant agent, 1,3-Dimethylthiourea (DMTU), was administered before and after the administration of cisplatin. The hot plate test was used to assess hypoalgesia. Oxidative stress in the sciatic nerve was assessed from thiobarbituric acid reactive substances (TBARs) and superoxide dismutase (SOD) activity. Nerve apoptosis was analysed with qRT-PCR. We observed an increase in TBARs and a decrease in SOD activity with the development of cisplatin-induced hypoalgesia, which was ameliorated by DMTU treatment. Furthermore, differences in the dosing time of cisplatin caused differences in oxidative stress which were correlated with cisplatin-induced hypoalgesia. Severe oxidative stress caused cisplatin-induced hypoalgesia, and chronotherapy with cisplatin ameliorated hypoalgesia by reducing oxidative stress. In the future, chronotherapy with cisplatin may contribute to the treatment of cancer in humans.

Treatment for chemotherapy-induced peripheral neuropathy: A systematic review of randomized control trials

Purpose: Treatment of chemotherapy-induced peripheral neuropathy (CIPN) is challenging for clinicians, and many clinical trials and meta-analyses on CIPN are controversial. There are also few comparisons of the efficacy among drugs used to treat CIPN. Therefore, this systematic review aimed to study the efficacy of drugs in treating CIPN using existing randomized controlled trials. Methods: Electronic databases were searched for randomized controlled trials (RCTs) involving any pharmaceutical intervention and/or combination therapy of treating CIPN. Results: Seventeen RCTs investigating 16 drug categories, duloxetine, pregabalin, crocin, tetrodotoxin, venlafaxine, monosialotetrahexosyl ganglioside (GM1), lamotrigine, KA (ketamine and amitriptyline) cream, nortriptyline, amitriptyline, topical Citrullus colocynthis (bitter apple) oil, BAK (baclofen, amitriptyline hydrochloride, and ketamine) pluronic lecithin organogel, gabapentin, and acetyl l-carnitine (ALC), in the treatment of CIPN were retrieved. Many of the included RCTs consisted of small sample sizes and short follow-up periods. It was difficult to quantify due to the highly variable nature of outcome indicators. Conclusion: Duloxetine, venlafaxine, pregabalin, crocin, tetrodotoxin, and monosialotetrahexosyl ganglioside exhibited some beneficial effects in treating CIPN. Duloxetine, GM1, and crocin showed moderate benefits based on the evidence review, while lamotrigine, KA cream, nortriptyline, amitriptyline, and topical Citrullus colocynthis (bitter apple) oil were not beneficial. Further studies were necessary to confirm the efficacy of gabapentin in the treatment of CIPN because of the controversy of efficacy of gabapentin. Furthermore, BAK topicalcompound analgesic gel only had a tendency to improve the CIPN symptoms, but the difference was not statistically significant. ALC might result in worsening CIPN. Most studies were not of good quality because of small sample sizes. Therefore, standardized randomized controlled trials with large samples were needed to critically assess the effectiveness of these drugs in treating CIPN in the future.

The effectiveness and safety of acupuncture/electroacupuncture for chemotherapy-induced peripheral neuropathy: a systematic review and meta-analysis

OBJECTIVE

Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting adverse effect of anticancer agents with virtually no effective treatment. Safe and effective therapies are needed urgently. Acupuncture shows therapeutic possibilities in this regard but needs to be further evaluated.

METHODS

A systematic search was conducted in seven databases from their inception to April 2020. Randomized controlled trials (RCTs) focused on acupuncture/electroacupuncture (EA) for the treatment of CIPN were included. Revman 5.3 software was used for meta-analysis if there was no significant heterogeneity. Otherwise, qualitative analysis was utilized.

RESULTS

Nine studies involving 582 patients were included in this review. Most of the studies exhibited unclear risk of bias because some details were not mentioned. As the clinical heterogeneity was significant, qualitative analysis was performed to describe nerve conduction velocity, effective rate for motor neuropathy, pain scores, quality of life and adverse events. Meta-analysis was performed on four studies to analyze the effective rate for sensory neuropathy due to inconspicuous heterogeneity. The results indicated that acupuncture may generate a better effect on sensory neuropathy than vitamin B (risk ratio = 1.60, 95% confidence interval = 1.31-1.95, I² = 0%, p < 0.00001). The efficacy of EA plus glutathione (GSH) appeared to be better than that of GSH alone in alleviating sensory neurotoxicity and in improving nerve conduction velocity. Acupuncture plus methylcobalamin showed more favorable effects than methylcobalamin alone in relieving neuralgia, restoring nerve conduction velocity and improving quality of life. In terms of pain relief and improved CIPN-specific quality of life, acupuncture plus standard care was better than standard care alone. In terms of pain relief, EA was more effective than usual care.

CONCLUSION

Acupuncture may be effective and safe in the treatment of CIPN according to the analyzed studies. However, more studies with higher methodological quality are warranted in order to be able to draw firmer conclusions. Future rigorous RCTs will be necessary to confirm the effectiveness and safety of acupuncture for CIPN.

Updates in the Treatment of Chemotherapy-Induced Peripheral Neuropathy

OPINION STATEMENT

Chemotherapy-induced peripheral neuropathy (CIPN) is a common toxicity associated with treatment with platinum-based agents, taxanes, vinca alkaloids, and other specific agents. The long-term consequences of this condition can result in decreased patient quality of life and can lead to reduced dose intensity, which can negatively impact disease outcomes. There are currently no evidence-based preventative strategies for CIPN and only limited options for treatment. However, there are several strategies that can be utilized to improve patient experience and outcomes as more data are gathered in the prevention and treatment setting. Before treatment, patient education on the potential side effects of chemotherapy is key, and although trials have been limited, recommending exercise and a healthy lifestyle before and while undergoing chemotherapy may provide some overall benefit. In patients who develop painful CIPN, our approach is to offer duloxetine and titrate up to 60 mg daily. Chemotherapy doses may also need to be reduced if intolerable symptoms develop during treatment. Some patients may also try acupuncture and physical therapy to help address their symptoms, although this can be limited by cost, time commitment, and patient motivation. Additionally, data on these modalities are currently limited, as studies are ongoing. Overall, approaching each patient on an individual level and tailoring treatment options for them based on overall physical condition, their disease burden, goals of care and co-morbid health conditions, and willingness to trial different approaches is necessary when addressing CIPN.

The use of photobiomodulation therapy for the prevention of chemotherapy-induced peripheral neuropathy: a randomized, placebo-controlled pilot trial (NEUROLASER trial)

PURPOSE

The purpose of this study was to investigate the effectiveness of photobiomodulation (PBM) therapy for the prevention of chemotherapy-induced peripheral neuropathy (CIPN) in breast cancer patients.

METHODS

A prospective, randomized placebo-controlled pilot trial (NEUROLASER) was set up with 32 breast cancer patients who underwent chemotherapy (ClinicalTrials.gov; NCT03391271). Patients were randomized to receive PBM (n = 16) or placebo treatments (n = 16) (2 × /week) during their chemotherapy. The modified Total Neuropathy Score (mTNS), six-minute walk test (6MWT), Numeric pain Rating Scale (NRS), and Functional Assessment of Cancer Therapy/Gynecologic Oncology Group Taxane (FACT/GOG-Taxane) were used to evaluate the severity of CIPN and the patients' quality of life (QoL). Outcome measures were collected at the first chemotherapy session, 6 weeks after initiation of chemotherapy, at the final chemotherapy session, and 3 weeks after the end of chemotherapy (follow-up).

RESULTS

The mTNS score increased significantly over time in both the control and the PBM group. A significantly higher score for FACT/GOG-Taxane was observed in the PBM group during chemotherapy compared to the control group. Questions of the FACT/GOG-Taxane related to sensory peripheral neuropathy symptoms showed a significant increase in severeness over time in the control group, whereas they remained constant in the PBM group. At follow-up, a (borderline) significant difference was observed between both groups for the 6MWT and patients' pain level, in benefit of the PBM group.

CONCLUSIONS

This NEUROLASER trial shows promising results concerning the prevention of CIPN with PBM in breast cancer patients. Furthermore, a better QoL was observed when treated with PBM.

Chemotherapy-Induced Peripheral Neuropathy: Epidemiology, Pathomechanisms and Treatment

PURPOSE

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

FINDINGS

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

IMPLICATIONS

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

Chemotherapy-induced peripheral neuropathy and rehabilitation: A review

Chemotherapy-induced peripheral neuropathy (CIPN) is a common complication after chemotherapy that can damage the sensory, motor, autonomic, or cranial nerves in approximately 30%-60% of patients with cancer. CIPN can lead to detrimental dose modifications and/or premature chemotherapy discontinuation due to patient intolerance. The long-term impact of CIPN is particularly challenging and can have a profound impact on the quality of life (QoL) and survivorship. However, this condition is often underdiagnosed. No agents have been established to prevent CIPN. Pre-chemotherapy testing is recommended for high-risk patients. Duloxetine is considered a first-line treatment, whereas gabapentin, pregabalin, tricyclic antidepressants, and topical compounding creams may be used for neuropathic pain control. Home-based, low-to-moderate walking, and resistance exercise during chemotherapy can reduce the severity and prevalence of CIPN symptoms, especially in older patients. Pre-habilitation and rehabilitation should be recommended for all patients receiving cytotoxic chemotherapies. The purpose of this article is to review common chemotherapeutic drugs causing CIPN, risk factors, diagnosis and treatment of CIPN, and evidence of the benefits of rehabilitation.

Pain Relieving and Neuroprotective Effects of Non-opioid Compound, DDD-028, in the Rat Model of Paclitaxel-Induced Neuropathy

Chemotherapy-induced neuropathy (CIN) is a major dose-limiting side effect of anticancer therapy that can compel therapy discontinuation. Inadequate analgesic efficacy of current pharmacological approaches requires the identification of innovative therapeutics and, hence, the purpose of this study is to conduct a preclinical evaluation of the efficacy of DDD-028, a versatile pentacyclic pyridoindole derivative, against paclitaxel-induced neuropathic pain. In two separate experiments, DDD-028 was administered per os acutely (1-25 mg kg-1) or repeatedly (10 mg kg-1) in paclitaxel-treated rats. The response to mechanical noxious stimulus (paw pressure) as well as to non-noxious mechanical (von Frey) and thermal (cold plate) stimuli was investigated. Acute administration of DDD-028 induced a dose-dependent anti-neuropathic pain effect in all tests performed. Further, repeated daily treatment for 18 consecutive days (starting the first day of paclitaxel administration) significantly reduced the development of pain over time without the development of tolerance to the anti-hyperalgesic effect. Ex vivo analysis showed that DDD-028 was able to reduce oxidative damage of dorsal root ganglia as evidenced by the increase in the level of carbonylated proteins and the decrease in catalase activity. In the lumbar spinal cord, periaqueductal gray matter, thalamus, and somatosensory cortex 1, DDD-28 significantly prevented the activation of microglia and astrocytes. The pharmacodynamic study revealed that the pain-relieving effects of DDD-028 were fully blocked by both the non-selective nicotinic receptor (nAChR) antagonist mecamylamine and by the selective α7 nAChR antagonist methyllycaconitine. In conclusion, DDD-028 was active in reducing paclitaxel-induced neuropathic pain after single or repeated administrations without tolerance development and displaying a double symptomatic and neuroprotective profile. DDD-028 could represent a valuable candidate for the treatment of CIN.

Preliminary effects of low-intensity focused ultrasound treatment program for cancer-related neuropathic pain

Aim: To evaluate the effectiveness of low-intensity focused ultrasound (LIFU) therapy in the management of cancer-related neuropathic pain (CNP). Methods: A retrospective review with 22 patients with CNP treated with LIFU therapy (frequency 3 Hz, 3 W/cm², pulse mode duty cycle 50%) was conducted. Results: Out of the 22 patients, 15 had CNP secondary to chemotherapy-induced peripheral neuropathy. Compared with baseline, there was a significant reduction in numeric pain rating scale (p < 0.001). Additionally, 76.5% of patients (n = 13) were considered to be responders to LIFU therapy. Conclusion: LIFU therapy may be a viable treatment modality in the management of CNP, specifically chemotherapy-induced peripheral neuropathy, with a minimal side effect profile. Larger, prospective studies with a structured protocol are necessary.

Capsaicin 8% patch Qutenza and other current treatments for neuropathic pain in chemotherapy-induced peripheral neuropathy (CIPN)

PURPOSE OF REVIEW

Current oral treatments for neuropathic pain associated with chemotherapy-induced peripheral neuropathy (CIPN) have limited clinical efficacy, and undesirable side-effects. Topically delivered treatments have the advantage of avoiding CNS side-effects, while relieving pain. We have reviewed treatments of neuropathic pain associated with CIPN, focusing on the Capsaicin 8% patch, which can provide pain relief for up to 3 months or longer after a single 30-60-min application.

RECENT FINDINGS

Capsaicin 8% patch is a licensed treatment in the EU/UK for neuropathic pain and shown to be safe and effective in providing pain relief for patients with CIPN. Repeated daily oral or topical administrations are not required, as with other current treatments. The side-effects are transient and restricted to the time around patch application. New evidence suggests the Capsaicin 8% patch can promote the regeneration and restoration of skin nerve fibres in CIPN, in addition to the pain relief.

SUMMARY

The Capsaicin 8% patch is now often a preferred a treatment option for localised neuropathic pain conditions, including the feet and hands in patients with CIPN. Capsaicin 8% patch can be repeated three-monthly, if needed, for a year. In addition to pain relief, it may have a disease-modifying effect.

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.

Pharmacological Management of Painful Peripheral Neuropathies: A Systematic Review

Introduction

Peripheral neuropathic pain (PNP) arises either acutely or in the chronic phase of a lesion or disease of the peripheral nervous system and is associated with a notable disease burden. The management of PNP is often challenging. The aim of this systematic review was to evaluate current evidence, derived from randomized controlled trials (RCTs) that have assessed pharmacological interventions for the treatment of PNP due to polyneuropathy (PN).

Methods

A systematic search of the PubMed database led to the identification of 538 papers, of which 457 were excluded due to not meeting the eligibility criteria, and two articles were identified through screening of the reference lists of the 81 eligible studies. Ultimately, 83 papers were included in this systematic review.

Results

The best available evidence for the management of painful diabetic polyneuropathy (DPN) is for amitriptyline, duloxetine, gabapentin, pregabalin and venlafaxine as monotherapies and oxycodone as add-on therapy (level II of evidence). Tramadol appears to be effective when used as a monotherapy and add-on therapy in patients with PN of various etiologies (level II of evidence). Weaker evidence (level III) is available on the effectiveness of several other agents discussed in this review for the management of PNP due to PN.

Discussion

Response to treatment may be affected by the underlying pathophysiological mechanisms that are involved in the pathogenesis of the PN and, therefore, it is very important to thoroughly investigate patients presenting with PNP to determine the causes of this neuropathy. Future RCTs should be conducted to shed more light on the use of pharmacological approaches in patients with other forms of PNP and to design specific treatment algorithms.

Electronic supplementary material

The online version of this article (10.1007/s40122-020-00210-3) contains supplementary material, which is available to authorized users.

High-Dose 8% Capsaicin Patch in Treatment of Chemotherapy-Induced Peripheral Neuropathy. A Systematic Review

INTRODUCTION

This is a review of the evidence from studies of the efficacy and tolerability of topically applied and high-concentration (8%) capsaicin in chemotherapy-induced peripheral neuropathy.

METHODS

For this review, we searched EMBASE and MEDLINE to June 20, 2020. The terms used in the search included capsaicin, capsaicin 8% patch, chemotherapy-induced peripheral neuropathy, and cancer.

RESULTS

A total of 98 studies were obtained, but only five were selected for the final analysis, with a total of 95 patients included. Three of the studies are prospective and two retrospective, including less than 30 patients per study. Capsaicin 8% patch provides significant pain relief in chemotherapy-induced peripheral neuropathy in all of them. However, the small number of studies (and patients) evaluated require caution with these results.

CONCLUSION

Additional clinical trials are required to establish the definitive role of the capsaicin patch in the future.

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

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

Metformin protects from oxaliplatin induced peripheral neuropathy in rats

Oxaliplatin is a commonly used drug to treat cancer, extending the rate of disease-free survival by 20% in colorectal cancer. However, oxaliplatin induces a disabling form of neuropathy resulting in more than 60% of patients having to reduce or discontinue oxaliplatin, negatively impacting their chance of survival. Oxaliplatin-induced neuropathies are accompanied by degeneration of sensory fibers in the epidermis and hyperexcitability of sensory neurons. These morphological and functional changes have been associated with sensory symptoms such as dysesthesia, paresthesia and mechanical and cold allodynia. Various strategies have been proposed to prevent or treat oxaliplatin-induced neuropathies without success. The anti-diabetic drug metformin has been recently shown to exert neuroprotection in other chemotherapy-induced neuropathies, so here we aimed to test if metformin can prevent the development of oxaliplatin-induced neuropathy in a rat model of this condition. Animals treated with oxaliplatin developed significant intraepidermal fiber degeneration, a mild gliosis in the spinal cord, and mechanical and cold hyperalgesia. The concomitant use of metformin prevented degeneration of intraepidermal fibers, gliosis, and the altered sensitivity. Our evidence further supports metformin as a new approach to prevent oxaliplatin-induced neuropathy with a potential important clinical impact.

Taxane-induced neurotoxicity: Pathophysiology and therapeutic perspectives

Taxane-derived drugs are antineoplastic agents used for the treatment of highly common malignancies. Paclitaxel and docetaxel are the most commonly used taxanes; however, other drugs and formulations have been used, such as cabazitaxel and nab-paclitaxel. Taxane treatment is associated with neurotoxicity, a well-known and relevant side effect, very prevalent amongst patients undergoing chemotherapy. Painful peripheral neuropathy is the most dose-limiting side effect of taxanes, affecting up to 97% of paclitaxel-treated patients. Central neurotoxicity is an emerging side effect of taxanes and it is characterized by cognitive impairment and encephalopathy. Besides impairing compliance to chemotherapy treatment, taxane-induced neurotoxicity (TIN) can adversely affect the patient's life quality on a long-term basis. Despite the clinical relevance, not many reviews have comprehensively addressed taxane-induced neurotoxicity when they are used therapeutically. This article provides an up-to-date review on the pathophysiology of TIN and the novel potential therapies to prevent or treat this side effect.

Meet the expert: How I treat chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent, often irreversible and disabling adverse effect of many commonly used chemotherapeutic agents. Older patients are at particular risk of developing CIPN due to comorbid conditions affecting the health of peripheral nerves. Symptoms of CIPN include paresthesias, dysesthesias, sensory loss, motor weakness, dysautonomia, and falls. Pharmacologic management of CIPN involves use of medications including antidepressants, anticonvulsants, and topical treatments for modulation of neuropathic pain. These medications should be used and monitored carefully in older patients as they may increase the risk of confusion, falls, and drug-drug interactions. Patients with CIPN are at an increased risk of falls and should be considered for supportive care interventions including physical and occupational therapy, assistive devices, and safety evaluations. Surveillance of CIPN during and following treatment is essential. The development of neuropathic symptoms may require dose reduction, drug holiday, or transitioning to another chemotherapeutic agent. Symptoms of CIPN typically improve following exposure to neurotoxic therapy, although in older adults the rate of improvement may be slow, and recovery is often incomplete. Early involvement of a neurologist should be considered in patients with atypical, progressive, motor- or autonomic- predominant presentations of neuropathy. Patients with refractory neuropathic pain or those who cannot tolerate standard symptomatic treatment should be referred to a pain specialist or palliative care.

Bortezomib and other proteosome inhibitors-induced peripheral neurotoxicity: From pathogenesis to treatment

Proteasome inhibitors (PIs), especially bortezomib (BTZ), have come to the forefront over the last years because of their unprecedented efficacy mainly against multiple myeloma (MM). Unfortunately, peripheral neuropathy (PN) secondary to treatment of MM with PIs has emerged as a clinically relevant complication, which negatively impacts the quality of life of MM survivors. Bortezomib-induced peripheral neuropathy (BIPN) is a dose-limiting toxicity, which develops in 30% to 60% of patients during treatment. Typically, BIPN is a length-dependent sensory axonopathy characterized by numbness, tingling, and severe neuropathic pain in stocking and glove distribution. BIPN mechanisms have not yet been fully elucidated. Experimental studies suggest that aggresome formation, endoplasmic reticulum stress, myotoxicity, microtubule stabilization, inflammatory response, and DNA damage could contribute to this neurotoxicity. A new generation of structurally distinct PIs has been developed, being increasingly used in clinical settings. Carfilzomib exhibits a much lower neurotoxicity profile, with a significantly lower incidence of PN compared to BTZ. Pre-existing PN increases the risk of developing BIPN. Besides, BIPN is related to dose, schedule and mode of administration and modifications of these factors have lowered the incidence of PN. However, to date there is no cure for PIs-induced PN (PIIPN), and a careful neurological monitoring and dose adjustment is a key strategy for preserving quality of life. This review critically looks at the pathogenesis, incidence, risk factors, both clinical and pharmacogenetics, clinical phenotype and management of PIIPN. We also make recommendations for further elucidating the whole clinical spectrum of PIIPN.

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.

Taxane and epothilone-induced peripheral neurotoxicity: From pathogenesis to treatment

Taxane-induced peripheral neurotoxicity (TIPN) is the most common non-hematological side effect of taxane-based chemotherapy, and may result in dose reductions and discontinuations, having as such a detrimental effect on patients' overall survival. Epothilones share similar mechanism of action with taxanes. The typical TIPN clinical presentation is mainly comprised of numbness and paresthesia, in a stocking-and-glove distribution and may progress more proximally over time, with paclitaxel being more neurotoxic than docetaxel. Motor and autonomic involvement is less common, whereas an acute taxane-induced acute pain syndrome is frequent. Patient reported outcomes questionnaires, clinical evaluation, and instrumental tools offer complementary information in TIPN. Its electrodiagnostic features include reduced/abolished sensory action potentials, and less prominent motor involvement, in keeping with a length-dependent, axonal dying back predominately sensory neuropathy. TIPN is dose-dependent and may be reversible within months after the end of chemotherapy. The single and cumulative delivered dose of taxanes is considered the main risk factor of TIPN development. Apart from the cumulative dose, other risk factors for TIPN include demographic, clinical, and pharmacogenetic features with several single-nucleotide polymorphisms potentially linked with increased susceptibility of TIPN. There are currently no neuroprotective strategies to reduce the risk of TIPN, and symptomatic treatments are very limited. This review critically examines the pathogenesis, incidence, risk factors (both clinical and pharmacogenetic), clinical phenotype and management of TIPN.

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.

Effect of serotonin-norepinephrine reuptake inhibitors for patients with chemotherapy-induced painful peripheral neuropathy: A meta-analysis

BACKGROUND

To compare the efficacy of serotonin-norepinephrine reuptake inhibitors (SNRIs) treatment for chemotherapy-induced peripheral neuropathy (CIPN) METHODS:: Two authors independently searched MEDLINE, Embase, Cochran Library, and Web of Science to identify and review articles published from January 1998 until December 2018 according to selection criteria. Outcomes were expressed as mean difference, the pooled odds ratio, or relative risk in a meta-analysis model.

RESULTS

A total of 10 studies were included in this meta-analysis: 6 randomized-controlled studies and 4 observational studies. Meta-analysis showed that CIPN was improved after treatment with SNRI (standardized mean difference = 2.20; 95% confidence interval, 0.90-3.49; I = 93% in 3 randomized controlled studies). Somnolence and insomnia occurred in <15% of patients. Incidence of somnolence was lower than with pregabalin treatment, and insomnia was comparable to that in expectant management or pregabalin treatment. Incidence of nausea and vomiting was higher than in expectant management, but no significant difference was found when compared to expectant management.

CONCLUSION

From the several available studies suitable for indirect comparison, SNRI shows excellent efficacy and tolerability to CIPN. SNRI could provide an important treatment option for CIPN.

FoxO3a as a Positive Prognostic Marker and a Therapeutic Target in Tamoxifen-Resistant Breast Cancer

Background: Resistance to endocrine treatments is a major clinical challenge in the management of estrogen receptor positive breast cancers. Although multiple mechanisms leading to endocrine resistance have been proposed, the poor outcome of this subgroup of patients demands additional studies. Methods: FoxO3a involvement in the acquisition and reversion of tamoxifen resistance was assessed in vitro in three parental ER+ breast cancer cells, MCF-7, T47D and ZR-75-1, in the deriving Tamoxifen resistant models (TamR) and in Tet-inducible TamR/FoxO3a stable cell lines, by growth curves, PLA, siRNA, RT-PCR, Western blot, Immunofluorescence, Transmission Electron Microscopy, TUNEL, cell cycle, proteomics analyses and animal models. FoxO3a clinical relevance was validated in silico by Kaplan–Meier survival curves. Results: Here, we show that tamoxifen resistant breast cancer cells (TamR) express low FoxO3a levels. The hyperactive growth factors signaling, characterizing these cells, leads to FoxO3a hyper-phosphorylation and subsequent proteasomal degradation. FoxO3a re-expression by using TamR tetracycline inducible cells or by treating TamR with the anticonvulsant lamotrigine (LTG), restored the sensitivity to the antiestrogen and strongly reduced tumor mass in TamR-derived mouse xenografts. Proteomics data unveiled novel potential mediators of FoxO3a anti-proliferative and pro-apoptotic activity, while the Kaplan–Meier analysis showed that FoxO3a is predictive of a positive response to tamoxifen therapy in Luminal A breast cancer patients. Conclusions: Altogether, our data indicate that FoxO3a is a key target to be exploited in endocrine-resistant tumors. In this context, LTG, being able to induce FoxO3a, might represent a valid candidate in combination therapy to prevent resistance to tamoxifen in patients at risk.

Pharmacological Treatment of Chemotherapy-Induced Neuropathic Pain: PPARγ Agonists as a Promising Tool

Chemotherapy-induced neuropathic pain (CINP) is one of the most severe side effects of anticancer agents, such as platinum- and taxanes-derived drugs (oxaliplatin, cisplatin, carboplatin and paclitaxel). CINP may even be a factor of interruption of treatment and consequently increasing the risk of death. Besides that, it is important to take into consideration that the incidence of cancer is increasing worldwide, including colorectal, gastric, lung, cervical, ovary and breast cancers, all treated with the aforementioned drugs, justifying the concern of the medical community about the patient’s quality of life. Several physiopathological mechanisms have already been described for CINP, such as changes in axonal transport, mitochondrial damage, increased ion channel activity and inflammation in the central nervous system (CNS). Another less frequent event that may occur after chemotherapy, particularly under oxaliplatin treatment, is the central neurotoxicity leading to disorders such as mental confusion, catatonia, hyporeflexia, etc. To date, no pharmacological therapy has shown satisfactory effect in these cases. In this scenario, duloxetine is the only drug currently in clinical use. Peroxisome proliferator-activated receptors (PPARs) belong to the class of nuclear receptors and are present in several tissues, mainly participating in lipid and glucose metabolism and inflammatory response. There are three PPAR isoforms: α, β/δ and γ. PPARγ, the protagonist of this review, is expressed in adipose tissue, large intestine, spleen and neutrophils. This subtype also plays important role in energy balance, lipid biosynthesis and adipogenesis. The effects of PPARγ agonists, known for their positive activity on type II diabetes mellitus, have been explored and present promising effects in the control of neuropathic pain, including CINP, and also cancer. This review focuses largely on the mechanisms involved in chemotherapy-induced neuropathy and the effects of the activation of PPARγ to treat CINP. It is the aim of this review to help understanding and developing novel CINP therapeutic strategies integrating PPARγ signalling.

Opportunities for cannabis in supportive care in cancer

Cannabis has the potential to modulate some of the most common and debilitating symptoms of cancer and its treatments, including nausea and vomiting, loss of appetite, and pain. However, the dearth of scientific evidence for the effectiveness of cannabis in treating these symptoms in patients with cancer poses a challenge to clinicians in discussing this option with their patients. A review was performed using keywords related to cannabis and important symptoms of cancer and its treatments. Literature was qualitatively reviewed from preclinical models to clinical trials in the fields of cancer, human immunodeficiency virus (HIV), multiple sclerosis, inflammatory bowel disease, post-traumatic stress disorder (PTSD), and others, to prudently inform the use of cannabis in supportive and palliative care in cancer. There is a reasonable amount of evidence to consider cannabis for nausea and vomiting, loss of appetite, and pain as a supplement to first-line treatments. There is promising evidence to treat chemotherapy-induced peripheral neuropathy, gastrointestinal distress, and sleep disorders, but the literature is thus far too limited to recommend cannabis for these symptoms. Scant, yet more controversial, evidence exists in regard to cannabis for cancer- and treatment-related cognitive impairment, anxiety, depression, and fatigue. Adverse effects of cannabis are documented but tend to be mild. Cannabis has multifaceted potential bioactive benefits that appear to outweigh its risks in many situations. Further research is required to elucidate its mechanisms of action and efficacy and to optimize cannabis preparations and doses for specific populations affected by cancer.

Molecular Mechanisms of the Sense of Touch: An Overview of Mechanical Transduction and Transmission in Merkel Discs of Whisker Hair Follicles and Some Clinical Perspectives

The Merkel disc is a main type of tactile end organs for sensing gentle touch and is essential for sophisticated sensory tasks including social interaction, environmental exploration, and tactile discrimination. Recent studies have shown that Merkel cells are primary sites of mechanotransduction using Piezo2 channels as a molecular transducer in Merkel discs. Furthermore, tactile stimuli trigger serotonin release from Merkel cells to excite their associated whisker Aβ-afferent endings and transmit tactile signals. The tactile transduction and transmission at Merkel discs may have important clinical implications in sensory dysfunctions such as the loss of tactile sensitivity and tactile allodynia seen in patients who have diabetes and inflammatory diseases and undergo chemotherapy.

Rational treatment of chemotherapy-induced peripheral neuropathy with capsaicin 8% patch: from pain relief towards disease modification

Purpose

Chemotherapy-induced peripheral neuropathy (CIPN) with associated chronic pain is a common and disabling condition. Current treatments for neuropathic pain in CIPN are largely ineffective, with unfavorable side-effects. The capsaicin 8% patch (capsaicin 179 mg patch) is approved for the treatment of neuropathic pain: a single topical cutaneous application can produce effective pain relief for up to 12 weeks. We assessed the therapeutic potential of capsaicin 8% patch in patients with painful CIPN, and its mechanism of action.

Patients and methods

16 patients with chronic painful CIPN (mean duration 2.5 years), in remission for cancer and not receiving chemotherapy, were treated with 30 min application of capsaicin 8% patch to the feet. Symptoms were monitored using the 11-point numerical pain rating scale (NPRS), and questionnaires. Investigations were performed at baseline and three months after patch application, including skin biopsies with a range of markers, and quantitative sensory testing (QST).

Results

Patients reported significant reduction in spontaneous pain (mean NPRS: −1.27; 95% CI 0.2409 to 2.301; p=0.02), touch-evoked pain (−1.823; p=0.03) and cold-evoked pain (−1.456; p=0.03). Short-Form McGill questionnaire showed a reduction in neuropathic (p=0.0007), continuous (p=0.01) and overall pain (p=0.004); Patient Global Impression of Change showed improvement (p=0.001). Baseline skin biopsies showed loss of intra-epidermal nerve fibers (IENF), and also of sub-epidermal nerve fibers quantified by image analysis. Post-patch application skin biopsies showed a significant increase towards normalization of intra-epidermal and sub-epidermal nerve fibers (for IENF: structural marker PGP9.5, p=0.009; heat receptor TRPV1, p=0.027; regenerating nerve marker GAP43, p=0.04). Epidermal levels of Nerve Growth Factor (NGF), Neurotrophin-3 (NT-3), and Langerhans cells were also normalized. QST remained unchanged and there were no systemic side-effects, as in previous studies.

Conclusion

Capsaicin 8% patch provides significant pain relief in CIPN, and may lead to regeneration and restoration of sensory nerve fibers ie, disease modification.

Mitochondrial dysfunction in the pathogenesis of chemotherapy-induced peripheral neuropathy

Several first-line chemotherapeutic agents, including taxanes, platinum agents and proteasome inhibitors, are associated with the dose-limiting side effect of chemotherapy-induced peripheral neuropathy (CIPN). CIPN predominantly manifests as sensory symptoms, which are likely due to drug accumulation within peripheral nervous tissues rather than the central nervous system. No treatment is currently available to prevent or reverse CIPN. The causal mechanisms underlying CIPN are not yet fully understood. Mitochondrial dysfunction has emerged as a major factor contributing to the development and maintenance of CIPN. This chapter will provide an overview of both clinical and preclinical data supporting this hypothesis. We will review the studies reporting the nature of mitochondrial dysfunction evoked by chemotherapy in terms of changes in mitochondrial morphology, bioenergetics and reactive oxygen species (ROS) generation. Furthermore, we will discuss the in vivo effects of pharmacological interventions that counteract chemotherapy-evoked mitochondrial dysfunction and ameliorate pain-like behavior.

Mechanisms, Predictors, and Challenges in Assessing and Managing Painful Chemotherapy-Induced Peripheral Neuropathy

OBJECTIVE

To describe the known predictors and pathophysiological mechanisms of chronic painful chemotherapy-induced peripheral neuropathy (CIPN) in cancer survivors and the challenges in assessing and managing it.

DATA SOURCES

PubMed/Medline, CINAHL, Scopus, and PsycINFO.

CONCLUSION

The research on chronic painful CIPN is limited. Additional research is needed to identify the predictors and pathophysiological mechanisms of chronic painful CIPN to inform the development of assessment tools and management options for this painful and possibly debilitating condition.

IMPLICATIONS FOR NURSING PRACTICE

Recognition of the predictors of chronic painful CIPN and proactive CIPN assessment and palliative management are important steps in reducing its impact on physical function and quality of life.

Prevention and Management of Chemotherapy-Induced Polyneuropathy

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a severe and common side effect caused by a variety of antineoplastic agents. Approximately 30-40% of patients treated with agents such as taxanes, vinca alkaloids, or platinum derivatives will develop CIPN. CIPN presents predominantly as a sensory axonal neuro(no)pathy with occasional motor and autonomic dysfunction exhibiting considerable variability of clinical symptoms ranging from mild tingling sensation to severe neuropathic pain. Typical symptoms include numbness ("minus symptom"), weakness, and abnormal gait as well as paresthesia and pain ("positive symptoms"). As CIPN symptoms potentially lead to long-term morbidity and can even aggravate after cessation of therapy, patients' quality of life can be tremendously affected. In view of improved breast cancer survival outcomes, the late effects of CIPN are an unmet need in these patients. Therefore, early detection and assessment of first symptoms is important to effectively prevent severe CIPN. Therapeutic options for patients with CIPN are still limited, and pharmacological treatment focuses primarily on reduction or relief of neuropathic pain. CIPN is usually acutely managed by dose reduction or discontinuation of causative chemotherapy, potentially compromising treatment outcome. Currently, there is no causative proven therapy for the prevention of CIPN.

Characterization of Internal Validity Threats to Phase III Clinical Trials for Chemotherapy-Induced Peripheral Neuropathy Management: A Systematic Review

Objective:

The recent American Society of Clinical Oncology (ASCO) Clinical Guidelines for chemotherapy-induced peripheral neuropathy (CIPN) management (48 Phase III trials reviewed) only recommend duloxetine. However, before concluding that a CIPN intervention is ineffective, scientists and clinicians should consider the risk of Type II error in Phase III studies. The purpose of this systematic review was to characterize internal threats to validity in Phase III CIPN management trials.

Methods:

The PubMed, CINAHL, EMBASE^®, and Scopus databases were searched for Phase III clinical trials testing interventions for CIPN management between 1990 and 2018. The key search terms were neoplasms, cancer, neuropathy, and CIPN. Two independent researchers evaluated 24 studies, using a modified Joanna Briggs Institute Checklist for Randomized Control Trials developed by the authors specific for CIPN intervention trials.

Results:

Two studies exhibited minimal or no design flaws. 22/24 Phase III clinical trials for CIPN have two or greater design flaws due to sample heterogeneity, malapropos mechanism of action, malapropos intervention dose, malapropos timing of the outcome measurement, confounding variables, lack of a valid and reliable measurement, and suboptimal statistical validity.

Conclusions:

Numerous CIPN interventions have been declared ineffective based on the results of Phase III trials. However, internal validity threats to numerous studies may have resulted in Type II error and subsequent dismissal of a potentially effective intervention. Patients may benefit from rigorous retesting of several agents (e.g., alpha-lipoic acid, duloxetine, gabapentin, glutathione, goshajinkigan, lamotrigine, nortriptyline, venlafaxine, and Vitamin E) to expand and validate the evidence regarding ASCO's recommendations for CIPN management.

Tamoxifen suppresses paclitaxel-, vincristine-, and bortezomib-induced neuropathy via inhibition of the protein kinase C/extracellular signal-regulated kinase pathway

Chemotherapy-induced neuropathy is a highly problematic, dose-limiting effect of potentially curative regimens of cancer chemotherapy. When neuropathic pain is severe, patients often either switch to less-effective chemotherapy agents or choose to discontinue chemotherapy entirely. Conventional chemotherapy drugs used to treat lung and breast cancer, multiple myeloma, and lymphoma include paclitaxel, vincristine, and bortezomib. Approximately 68% of patients receiving these anticancer drugs develop neuropathy within the first month of treatment, and while strategies to prevent chemotherapy-induced neuropathy have been investigated, none have yet been proven as effective. Recent reports suggest that chemotherapy-induced neuropathy is associated with signal transduction molecules, including protein kinase C and mitogen-activated protein kinases. It is currently unclear whether protein kinase C inhibition can prevent chemotherapy-induced neuropathy. In this study, we found that tamoxifen, a protein kinase C inhibitor, suppressed paclitaxel-, vincristine-, and bortezomib-induced cold and mechanical allodynia in mice. In addition, chemotherapy drugs induce neuropathy via the protein kinase C/extracellular signal-regulated kinase pathway in the spinal cord in lumbar segments 4-6 and dorsal root ganglions. In addition, tamoxifen was shown to act synergistically with paclitaxel to inhibit tumor-growth in mice injected with tumor cells. Our results indicated that paclitaxel-, vincristine-, and bortezomib-induced neuropathies were associated with the protein kinase C/extracellular signal-regulated kinase pathway in the lumbar spinal cord and dorsal root ganglions, which suggest that protein kinase C inhibitors may be therapeutically effective for the prevention of chemotherapy-induced neuropathy when administered with standard chemotherapy agents.

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.

Scrambler therapy efficacy and safety for neuropathic pain correlated with chemotherapy-induced peripheral neuropathy in adolescents: A preliminary study

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of chemotherapy, in need of effective treatment. Preliminary data support the efficacy of scrambler therapy (ST), a noninvasive cutaneous electrostimulation device, in adults with CIPN. We test the efficacy, safety, and durability of ST for neuropathic pain in adolescents with CIPN.

PATIENTS AND METHODS

We studied nine pediatric patients with cancer and CIPN who received ST for pain control. Each patient received 45-min daily sessions for 10 consecutive days as a first step, but some of them required additional treatment.

RESULTS

Pain significantly improved comparing Numeric Rate Scale after 10 days of ST (9.22 ± 0.83 vs. 2.33 ± 2.34; P < 0.001) and at the end of the optimized cycle (EOC) (9.22 ± 0.83 vs. 0.11 ± 0.33, P < 0.001). The improvement in quality of life was significantly reached on pain interference with general activity (8.67 ± 1.66 vs. 3.33 ± 2.12, P < 0.0001), mood (8.33 ± 3.32 vs. 2.78 ± 2.82, P < 0.0005), walking ability (10.00 vs. 2.78 ± 1.22, P < 0.0001), sleep (7.56 ± 2.24 vs. 2.67 ± 1.41, P < 0.001), and relations with people (7.89 ± 2.03 vs. 2.11 ± 2.03, P < 0.0002; Lansky score 26.7 ± 13.2 vs. 10 days of ST 57.8 ± 13.9, P < 0.001; 26.7 ± 13.2 vs. EOC 71.1 ± 16.2, P < 0.001).

CONCLUSION

Based on these preliminary data, ST could be a good choice for adolescents with CIPN for whom pain control is difficult. ST caused total relief or dramatic reduction in CIPN pain and an improvement in quality of life, durable in follow-up. It caused no detected side effects, and can be retrained successfully. Further larger studies should be performed to confirm our promising preliminary data in pediatric patients with cancer.

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

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

FoxO3a Mediates the Inhibitory Effects of the Antiepileptic Drug Lamotrigine on Breast Cancer Growth

Breast cancer is a complex and heterogeneous disease, with distinct histologic features dictating the therapy. Although the clinical outcome of breast cancer patients has been considerably improved, the occurrence of resistance to common endocrine and chemotherapy treatments remains the major cause of relapse and mortality. Thus, efforts in identifying new molecules to be employed in breast cancer therapy are needed. As a "faster" alternative to reach this aim, we evaluated whether lamotrigine, a broadly used anticonvulsant, could be "repurposed" as an antitumoral drug in breast cancer. Our data show that lamotrigine inhibits the proliferation, the anchorage-dependent, and independent cell growth in breast cancer cells (BCC), including hormone-resistant cell models. These effects were associated with cell-cycle arrest and modulation of related proteins (cyclin D1, cyclin E, p27^Kip1, and p21^Waf1/Cip1), all target genes of FoxO3a, an ubiquitous transcription factor negatively regulated by AKT. Lamotrigine also increases the expression of another FoxO3a target, PTEN, which, in turn, downregulates the PI3K/Akt signaling pathway, with consequent dephosphorylation, thus activation, of FoxO3a. Moreover, lamotrigine induces FoxO3a expression by increasing its transcription through FoxO3a recruitment on specific FHRE located on its own promoter, in an autoregulatory fashion. Finally, lamotrigine significantly reduced tumor growth in vivo, increasing FoxO3a expression.Implications: The anticonvulsant drug lamotrigine shows strong antiproliferative activity on breast cancer, both in vitro and in vivo Thus, drug repurposing could represent a valuable option for a molecularly targeted therapy in breast cancer patients. Mol Cancer Res; 16(6); 923-34. ©2018 AACR.

High-Intensity Ultrasound Treatment for Vincristine-Induced Neuropathic Pain

BACKGROUND

Vincristine is a commonly used chemotherapeutic agent that results in debilitating untreatable peripheral neuropathy.

OBJECTIVE

To determine the effects of pulsed high-intensity focused ultrasound (HIFU) on sensory thresholds in a validated vincristine-induced neuropathy (VIN) rodent model.

METHODS

VIN was induced and mechanical allodynia was confirmed by nociceptive testing. von Frey fibers and Randall-Sellito test were used as measures of innocuous and noxious mechanical thresholds, respectively, and the hot plate test for thermal thresholds. Tests were performed before VIN, after 2 wk of vincristine, at 24, 48, 72, and 120 h after HIFU applied to the left L5 dorsal root ganglia at 3 Watts for 3 min. Comparisons were made between a VIN cohort who underwent HIFU, a VIN cohort who underwent sham HIFU, and naïve rodents who underwent HIFU.

RESULTS

VIN HIFU rats had significantly increased mechanical thresholds at 24 h (P &lt; .001), 48 h (P = .008), 72 h (P = .003), and 120 h (P = .03) after treatment, when compared to pre-HIFU thresholds. Furthermore, at 24 and 48 h following treatment, VIN HIFU rats had significantly higher innocuous and noxious mechanical thresholds and thermal thresholds than VIN sham HIFU rats (P &lt; .001). Thresholds were not altered in naïve rodents who underwent HIFU. Histological data of L5 dorsal root ganglia of VIN HIFU rats suggest that transient cellular edema resolves by 48 h.

CONCLUSION

Our data suggest that HIFU increases mechanical and thermal thresholds in VIN rodents. Whether HIFU can preclude the development of reduced thresholds in the VIN model warrants further study.

Anticonvulsants or Antidepressants in Combination Pharmacotherapy for Treatment of Neuropathic Pain in Cancer Patients: A Systematic Review and Meta-analysis

OBJECTIVE

To investigate the efficacy of anticonvulsants or antidepressants in combination pharmacotherapy for treatment of neuropathic pain in cancer patients.

MATERIALS AND METHODS

We systematically searched the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and the metaRegister of Controlled Trials for randomized controlled trials that compared anticonvulsants or antidepressants in combination pharmacotherapy (experimental group) with treatments without anticonvulsants or antidepressants (control group) for neuropathic pain in cancer patients. Risk of bias was evaluated in accordance with the Cochrane Handbook for Systematic Reviews of Interventions. The primary outcome was a mean difference (MD) in change in global pain analyzed by a random-effects model.

RESULTS

Eight trials met the inclusion criteria with a total of 1359 participants of whom 698 received an experimental intervention. The MD in change in global pain suggested a favorable association with anticonvulsants or antidepressants in combination pharmacotherapy compared with control groups (MD, -0.41; 95% confidence interval, -0.70 to -0.12) with no heterogeneity across trials (I=0%). The MD in change estimated in all sensitivity analyses ranged from -0.36 to -0.47, suggesting that these effects were consistent across different study designs and statistical assumptions.

CONCLUSIONS

Anticonvulsants or antidepressants in combination pharmacotherapy reduce neuropathic pain in cancer patients compared with treatments without anticonvulsants or antidepressants. Limited evidence precludes a recommendation on specific adjuvants in combination pharmacotherapy.

Risk-reduction and treatment of chemotherapy-induced peripheral neuropathy

INTRODUCTION

Chemotherapy-induced peripheral neuropathy (CIPN), a common adverse effect of several chemotherapeutic agents, has a significant impact on quality of life and may even compromise treatment efficacy, requiring chemotherapy dose reduction or discontinuation. CIPN is predominantly related with sensory rather than motor symptoms and the most common related cytotoxic agents are platinum compounds, taxanes and vinca alkaloids. CIPN symptoms may resolve after treatment cessation, but they can also be permanent and continue for years. Areas covered: We present an overview of CIPN pathophysiology, clinical assessment, prevention and treatment identified through a Pubmed search. Expert commentary: No substantial progress has been made in the last few years within the field of prevention and/or treatment of CIPN, in spite of remarkable efforts. Continuous research could expand our knowledge about chemotherapeutic-specific neuropathic pathways and eventually lead to the conception of innovative and targeted agents for the prevention and/or treatment of this debilitating chemotherapy adverse effect.

Pain in chemotherapy-induced peripheral neurotoxicity

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a potentially dose-limiting side effect of the treatment of several cancers. CIPN is predominantly or exclusively sensory, and it is frequently associated with unpleasant symptoms, overall referred to as "pain." However, given the markedly different clinical presentation and course of CIPN depending on the antineoplastic drug used, the broad term "pain" in the specific context of CIPN needs to be reconsidered and refined. In fact, a precise identification of the features of CIPN has relevant implication in the design of rational-based clinical trials and in the selection of possible active drugs.

Pathophysiology of Chemotherapy-Induced Peripheral Neuropathy

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