Somatosensory predictors of response to pregabalin in painful chemotherapy-induced peripheral neuropathy: a randomized, placebo-controlled, crossover study

Co-treatment with Gabapentinoid and Japanese Herbal Medicine Goshajinkigan for CIPN is Associated with Longer Duration and Higher Dose of Chemotherapy

INTRODUCTION

In Japan, both gabapentinoids and the Japanese traditional herbal medicine goshajinkigan (GJG) are used to manage chemotherapy-induced peripheral neuropathy (CIPN); however, evidence for their effectiveness is inconclusive. Patients with CIPN experience reduced quality of life and often undergo reductions in dose or discontinuation of chemotherapy. Therefore, this retrospective cohort study used a real-world database to examine the efficacy of gabapentinoids and GJG therapy for patients with CIPN by evaluating chemotherapy duration and dose.

METHODS

Data from 145,384 patients diagnosed with CIPN while receiving platinum- or taxane-based chemotherapy between April 1, 2008 and March 31, 2022 were stratified by CIPN treatment: simultaneous gabapentinoid (mirogabalin or pregabalin) plus GJG (prescription dates overlap); non-simultaneous gabapentinoid plus GJG (prescription dates do not overlap); gabapentinoid alone; GJG alone; and neither gabapentinoids nor GJG. Duration and dose of chemotherapy were the primary outcomes.

RESULTS

Treatment with either a gabapentinoid or GJG alone was associated with longer duration and higher doses of chemotherapy versus neither gabapentinoids nor GJG in patients treated with carboplatin, cisplatin, or paclitaxel. Combined gabapentinoid plus GJG treatment elicited further longer duration and higher doses of chemotherapy versus gabapentinoid alone or GJG alone in patients treated with carboplatin, oxaliplatin, cisplatin, paclitaxel, or docetaxel. When stratified by cancer type, similar trends were observed regarding combination gabapentinoid plus GJG treatment among patients with colorectal cancer treated with oxaliplatin and patients with gastric, lung, or breast cancer treated with paclitaxel.

CONCLUSION

Combination treatment with gabapentinoid plus GJG might prevent reductions in dose or discontinuation of chemotherapy, and might be effective for the treatment of CIPN.

Beyond p-values: a cross-sectional umbrella review of chemotherapy-induced peripheral neuropathy treatments

Introduction

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of neurotoxic chemotherapy agents, significantly impacting the daily lives of many cancer survivors. Despite thousands of articles published on CIPN, we remain no closer to a successful treatment regimen for the condition. In recent years, several new clinical trials and systematic reviews have been published, many exploring nonpharmaceutical interventions, prompting the need for a comprehensive synthesis of this emerging evidence.

Methods

We conducted an umbrella review to identify and appraise the 19 systematic reviews (SRs) published in 2023 that examined randomized controlled trials (RCTs) for established CIPN treatment. We focused our analysis on the three most researched treatment options: oral drugs, exercise, and acupuncture. RCTs not previously synthesized together were reviewed, and effect size analyses were performed to allow readers to interpret the existing literature beyond binary p-values.

Results

Our analysis of RCTs revealed the following key findings. For cancer survivors with CIPN after completing chemotherapy, serotonin-norepinephrine reuptake inhibitors (SNRIs) as well as acupuncture provided at least short-term relief for pain and sensory symptoms. For patients with CIPN who were actively undergoing chemotherapy, home-based balance and strength training exercises appeared to alleviate symptoms. Effect size analyses highlighted variability in treatment responses, underscoring the limitations of relying solely on p-values to assess intervention efficacy.

Discussion

Through an umbrella review approach, we demonstrate that SRs are often less systematic than expected. None of the 19 SRs captured all relevant RCTs within their search timeframe. However, by cross-referencing SRs, we identified 41 RCTs across 42 publications, illustrating the feasibility of an umbrella review approach to uncover relevant trials. Furthermore, many SRs exhibited methodological concerns that limit the interpretability of their findings. Finally, we discuss multiple opportunities for refining methods and reporting in future CIPN treatment trials.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024508283, PROSPERO (42024508283).

Pharmacological Treatment of Chemotherapy-Induced Neuropathy: A Systematic Review of Randomized Clinical Trials

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) affects up to 80% of patients undergoing cytotoxic chemotherapy. This painful condition significantly impairs quality of life and often necessitates dose reduction or discontinuation of chemotherapy, negatively impacting overall survival. Currently, duloxetine is the only pharmacological treatment recommended by the American Society of Clinical Oncology (ASCO). This systematic review aims to evaluate the efficacy of various pharmacological interventions in CIPN treatment, providing substantial evidence for clinical practice and future research.

DESIGN

This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to assess the effectiveness of pharmacological treatments for CIPN.

METHODS

Only randomized controlled trials (RCTs) were included. Herbal and phytotherapeutic treatments were excluded. Two independent reviewers performed the study selection, with a third reviewer resolving disagreements. Risk of bias assessment was conducted using the COCHRANE's RoB 2 tool.

RESULTS

Out of 860 screened articles, 17 RCTs met the inclusion criteria, encompassing 15 different pharmacological agents. Duloxetine, pregabalin, and amitriptyline were the most studied. Thirteen studies utilized a placebo as a control. Investigated medications exhibited varied outcomes, with some showing significant benefits in reducing neuropathic pain while others did not demonstrate statistically significant efficacy.

CONCLUSION

Duloxetine is an effective and well-tolerated option, while pregabalin shows promising results but requires further investigation. Other agents, such as venlafaxine and tapentadol, lack strong supporting evidence. Treatments like acetyl-l-carnitine, monosialotetrahexo-sylganglioside 1, and tetrodoxine yield inconsistent results, highlighting the need for additional research. Larger RCTs are recommended for comprehensive evaluation. Nurses are essential in CIPN care by monitoring symptoms, educating patients, and collaborating with the team.

Clinical pharmacology of neuropathic pain

This chapter aims to review the current pharmacological options for neuropathic pain treatment, their mechanisms of action, and future directions for clinical practice. Achieving pain relief in neuropathic pain conditions remains a challenge in clinical practice. The field of pharmacotherapy for neuropathic pain has encountered significant difficulties in translating substantial advances in our understanding of the underlying pathophysiological mechanisms into clinically effective therapies. This chapter presents the drugs recommended for the pharmacotherapy of neuropathic pain, based on the widely accepted treatment guidelines formulated by the Neuropathic Pain Special Interest Group of the International Association for the Study of Pain. In addition to discussing how the evidence base is created as part of international consortia, the drugs are also examined in terms of their putative molecular mechanisms as well as pharmacological pleiotropy, i.e., their potential unspecific and multi-target effects resulting in modulation of neuronal hyperexcitability. The chapter closes with a discussion of potential future developments in the field.

Neuropathic pain - A clinical primer

Neuropathic pain is used both as a mechanistic descriptor and a classification category of pain caused by a lesion or disease of the somatosensory nervous system and encompasses a vast array of possible diagnoses. The identification of neuropathic pain and diagnosis of specific syndromes relies on a detailed patient history. Standardized pain questionnaires can capture the patient`s symptoms, while the anatomical distribution of pain is often documented using pain drawings. Following this, a thorough clinical neurological examination is conducted to identify distinct sensory abnormalities, specifically sensory deficits and signs of increased sensitivity such as allodynia and hyperalgesia, within the pain-affected areas. Regardless of whether the lesion or disease is in the peripheral or central somatosensory nervous system, the presence of clinically overt sensory abnormalities is a key feature, distinguishing neuropathic pain from other types of pain, such as nociceptive pain, which likely coexist in neurological disorders. Extensive sensory deficits, as seen in certain stroke syndromes or following spinal cord injuries, may increase the likelihood of concomitant non-neuropathic pain within the same area of sensory loss. For this reason, differential diagnosis is essential when assessing patients with suspected neuropathic pain. Further diagnostic tests, including imaging or specific neurophysiological methods that assess nociceptive pathways, can provide objective evidence of a lesion or disease within the somatosensory nervous system. However, the causality between the lesion and the presence of neuropathic pain cannot be established definitively and always requires clinical judgment and interpretation within the broader context of the neurological disorder.

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.

Personalized treatment of neuropathic pain: Where are we now?

BACKGROUND

The treatment of neuropathic pain remains a major unmet need that the development of personalized and refined treatment strategies may contribute to address.

DATABASE

In this narrative review, we summarize the various approaches based on objective biomarkers or clinical markers that could be used.

RESULTS

In principle, the validation of objective biomarkers would be the most robust approach. However, although promising results have been reported demonstrating a potential value of genomics, anatomical or functional markers, the clinical validation of these markers has only just begun. Thus, most of the strategies documented to date have been based on the development of clinical markers. In particular, many studies have suggested that the identification of specific subgroups of patients presenting with specific combinations of symptoms and signs would be a relevant approach. Two main approaches have been used to identify relevant sensory profiles: quantitative sensory testing and specific patients reported outcomes based on description of pain qualities.

CONCLUSION

We discuss here the advantages and limitations of these approaches, which are not mutually exclusive.

SIGNIFICANCE

Recent data indicate that various new treatment strategies based on predictive biological and/or clinical markers could be helpful to better personalized and therefore improve the management of neuropathic pain.

Advances and challenges in neuropathic pain: a narrative review and future directions

Over the past few decades, substantial advances have been made in neuropathic pain clinical research. An updated definition and classification have been agreed. Validated questionnaires have improved the detection and assessment of acute and chronic neuropathic pain; and newer neuropathic pain syndromes associated with COVID-19 have been described. The management of neuropathic pain has moved from empirical to evidence-based medicine. However, appropriately targeting current medications and the successful clinical development of drugs acting on new targets remain challenging. Innovative approaches to improving therapeutic strategies are required. These mainly encompass rational combination therapy, drug repurposing, non-pharmacological approaches (such as neurostimulation techniques), and personalised therapeutic management. This narrative review reports historical and current perspectives regarding the definitions, classification, assessment, and management of neuropathic pain and explores potential avenues for future research.

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.

Pregabalin for chemotherapy-induced neuropathy: background and rationale for further study

Chemotherapy-induced neuropathy is difficult to manage, and the pain associated with neuropathy is poorly responsive to gabapentin in a randomized trial. Duloxetine is the only drug that has been found to be effective in reducing pain from chemotherapy neuropathy. In this qualitative review, the use of pregabalin for chemotherapy-induced neuropathy is discussed including the rationale and pharmacological reasons why pregabalin should be considered in a large, randomized placebo-controlled trial.

Pharmacological and Nonpharmacological Management of Chemotherapy-Induced Peripheral Neuropathy: A Scoping Review of Randomized Controlled Trials

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and debilitating side effect of cancer treatment with no effective preventative strategy or definitive treatment. Purpose: To synthesize empiric literature from randomized controlled trials (RCTs) of pharmacological and nonpharmacological management of CIPN. Data Sources: Articles published between January 1, 2010, and February 28, 2021, were identified using keywords searching Medline, PubMed, CINAHL, Web of Science, Cochrane Library, and Embase. Study Selection: RCTs that recruited individuals who were post-chemotherapy and experienced persistent CIPN symptoms. Data Extraction and Synthesis: Three independent reviewers screened a total of 2023 abstracts. After screening, full-text review, and quality appraisal, 22 articles were included in this review. Data related to study design, participant characteristics, interventions, controls, outcome measures, and relevant findings were extracted from full texts. Descriptive quantitative summaries were calculated and narrative analysis was performed. Results: Of the 22 studies, 4 investigated pharmacologic treatments, 2 compared acupuncture to pharmacologic treatments, and 16 studies examined nonpharmacologic treatments. Pharmacologic studies reported mixed results with evidence of participant response varying by history of chemotherapeutic agent. Acupuncture, exercise/physical therapy, and neurofeedback appear to be effective treatments for CIPN. Evidence regarding biophysical agents and cognitive-behavioral therapy is equivocal. Scrambler therapy is not supported. Limitations: Studies included in this review share several limitations, including widely variable outcome measures, small and demographically homogenous samples, and nonstandardized treatment protocols. Conclusion: This scoping review summarized the current body of high-quality RCTs investigating treatment for CIPN. The majority of studies in this review reports benefits of pharmacologic and nonpharmacologic interventions, although management may require a multipronged approach and should be tailored to the individual. Clinical implications are proposed and suggestions made for future research include implementation of standardized intervention protocols, use of outcome measures representative of the spectrum of CIPN symptoms, and stratification by the chemotherapeutic agent.

Current and Emerging Pharmacotherapeutic Interventions for the Treatment of Peripheral Nerve Disorders

Peripheral nerve disorders are caused by a range of different aetiologies. The range of causes include metabolic conditions such as diabetes, obesity and chronic kidney disease. Diabetic neuropathy may be associated with severe weakness and the loss of sensation, leading to gangrene and amputation in advanced cases. Recent studies have indicated a high prevalence of neuropathy in patients with chronic kidney disease, also known as uraemic neuropathy. Immune-mediated neuropathies including Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy may cause significant physical disability. As survival rates continue to improve in cancer, the prevalence of treatment complications, such as chemotherapy-induced peripheral neuropathy, has also increased in treated patients and survivors. Notably, peripheral neuropathy associated with these conditions may be chronic and long-lasting, drastically affecting the quality of life of affected individuals, and leading to a large socioeconomic burden. This review article explores some of the major emerging clinical and experimental therapeutic agents that have been investigated for the treatment of peripheral neuropathy due to metabolic, toxic and immune aetiologies.

Drug treatment for chemotherapy-induced peripheral neuropathy in patients with pancreatic cancer

Pancreatic cancer (PC) is a lethal disease where most tumors are too advanced at diagnosis for resection, leaving chemotherapy as the mainstay of treatment. Although the prognosis of unresectable PC is poor, it has been dramatically improved by new chemotherapy treatments, such as the combination of 5-fluorouracil, oxaliplatin, irinotecan, and leucovorin (FOLFIRINOX) or gemcitabine plus nab-paclitaxel. However, as oxaliplatin and paclitaxel are common neurotoxic drugs, chemotherapy-induced peripheral neuropathy (CIPN) is a common and severe adverse effect of both treatments. As there are no agents recommended in the ASCO guidelines, we review the methods used to treat CIPN caused by PC treatment. The efficacy of duloxetine was observed in a large randomized controlled trial (RCT). In addition, pregabalin was more effective than duloxetine for CIPN in two RCTs. Although duloxetine and pregabalin can be effective for CIPN, they have several side effects. Therefore, the choice between the two drugs should be determined according to effect and tolerability. Mirogabalin is also used in patients with PC and there is hope it will yield positive outcomes when treating CIPN in the future.

Mirogabalin vs pregabalin for chemotherapy-induced peripheral neuropathy in pancreatic cancer patients

BACKGROUND

The prognosis of pancreatic cancer (PC) has been improved by new chemotherapy regimens (combination of 5-fluorouracil, oxaliplatin, irinotecan, and leucovorin (FOLFIRINOX) or gemcitabine plus nab-paclitaxel (GnP)). Unfortunately, chemotherapy-induced peripheral neuropathy (CIPN) is a common adverse event of these two regimens. The efficacy of pregabalin for CIPN has been reported in previous studies. However, the efficacy of mirogabalin for CIPN remains unknown. Thus, in this study, we aimed to clarify which drug (mirogabalin or pregabalin) was more valuable for improving CIPN.

METHODS

A total of 163 PC patients who underwent FOLFIRINOX or GnP between May 2014 and January 2021 were enrolled. Among them, 34 patients were diagnosed with CIPN. Thirteen patients were treated with mirogabalin (mirogabalin group), and twenty-one patients were treated with pregabalin (pregabalin group). Treatment efficacy was compared between the two groups.

RESULTS

In both the mirogabalin group and the pregabalin group, the grade of patients with CIPN at 2, 4, and 6 weeks after the initiation of treatment showed significant improvement compared to the pretreatment grade. Notably, the rate of CIPN improvement was higher in the mirogabalin group than in the pregabalin group (2 weeks: 84.6% (11/13) vs 33.3% (7/21), P value = 0.005; 4 weeks, 6 weeks: 92.3% (12/13) vs 33.3% (7/21), P value = 0.001).

CONCLUSIONS

Although both mirogabalin and pregabalin were effective at improving CIPN, mirogabalin might be a suitable first choice for CIPN in PC patients.

TRIAL REGISTRATION

Not applicable.

Prediction of Individual Analgesic Response to Intravenous Lidocaine in Painful Diabetic Peripheral Neuropathy: A Randomized, Placebo-controlled, Crossover Trial

OBJECTIVES

Intravenous lidocaine can alleviate painful diabetic peripheral neuropathy (DPN) in some patients. Whether quantitative sensory testing (QST) can identify treatment responders has not been prospectively tested.

MATERIALS AND METHODS

This was a prospective, randomized, double-blind, crossover, placebo-controlled trial comparing intravenous lidocaine to normal saline (placebo) for painful DPN. Thirty-four participants with painful DPN were enrolled and administered intravenous lidocaine (5 mg/kg ideal body weight) or placebo as a 40-minute infusion, after a battery of QST parameters were tested on the dorsal foot, with a 3-week washout period between infusions.

RESULTS

Thirty-one participants completed both study sessions and were included in the final analysis. Lidocaine resulted in a 51% pain reduction 60 to 120 minutes after infusion initiation, as assessed on a 0 to 10 numerical rating scale, while placebo resulted in a 33.5% pain reduction (difference=17.6%, 95% confidence interval [CI], 1.9%-33.3%, P=0.03). Neither mechanical pain threshold, heat pain threshold, or any of the other measured QST parameters predicted the response to treatment. Lidocaine administration reduced mean Neuropathic Pain Symptom Inventory paresthesia/dysesthesia scores when compared with placebo by 1.29 points (95% CI, -2.03 to -0.55, P=0.001), and paroxysmal pain scores by 0.84 points (95% CI, -1.62 to -0.56, P=0.04), without significant changes in burning, pressing or evoked pain subscores.

DISCUSSION

While some participants reported therapeutic benefit from lidocaine administration, QST measures alone were not predictive of response to treatment. Further studies, powered to test more complex phenotypic interactions, are required to identify reliable predictors of response to pharmacotherapy in patients with DPN.

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

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

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

Bedside testing for precision pain medicine

PURPOSE OF REVIEW

In recent years, the identification of therapy responders has become an increasing focus of pain research. On the basis of laboratory quantitative sensory testing, subgroups of patients were identified, which have been shown to predict treatment response. However, the high cost and time expenditure limits the use of these lab-QST protocols in clinical practice and large clinical trials.

RECENT FINDINGS

Recently, different bedside testing protocols were developed as easy-to-use alternative for lab-QST. In addition, patients can be subgrouped based on their symptoms by use of patient-reported outcome measures. First results suggest that these approaches can be used to stratify patients into pathophysiological-plausible subgroups predictive for treatment response.

SUMMARY

This review presents recently developed bedside approaches that can be implemented as stratification tools in future clinical trials to realize individualized pain medicine. Being complementary rather than replaceable, future studies should combine questionnaires and sensory testing and apply them prospectively in large clinical trials.

Prevention, diagnosis and management of chemotherapy-induced peripheral neuropathy: a cross-sectional study of French oncologists' professional practices

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is challenging for oncologists. Many publications mention the high incidence of CIPN and the lack of effective preventive/management strategies and robust diagnostic tools. This cross-sectional study was aimed at assessing the practice of French oncologists for CIPN prevention, diagnosis and management.

METHODS

This web-based survey was sent to French oncologists by the regional cancer networks. Incidence and impact of CIPN were assessed using visual analogue scales (VAS) and diagnostic strategies were recorded. Also recorded were the drugs used to prevent or manage CIPN and their perceived efficacy and safety (VAS).

RESULTS

Among the 210 oncologists included, the perceived incidence of CIPN was about 36.2 ± 22.1% of patients. About 99.5% of oncologists declared that they assess CIPN during medical follow-up. The use of drugs to prevent CIPN was reported by 9.6% of oncologists (group B vitamins (35.0%) and calcium and magnesium infusion (25.0%)). In the case of CIPN, the therapeutic adjustment of neurotoxic anticancer drugs is performed by 99.0% of oncologists (chemotherapy change (49.8%), dose reduction (30.9%) or interruption (19.3%)). The pharmacological management of CIPN was declared by 72.9% of oncologists. The main drugs used are pregabalin (75.8%), amitriptyline (32.7%) and gabapentin (25.5%). Duloxetine (ASCO recommendation) is used by only 11.8% of oncologists.

CONCLUSION

Oncologists were clearly aware of CIPN risks, but its incidence tended to be underestimated and the ASCO recommendations for the management of CIPN were not followed. The prevention, diagnosis and management of CIPN remain problematic in clinical practice in France.

TRIAL REGISTRATION

ClinicalTrials.gov : NCT03854864.

Management of pain in colorectal cancer patients

In this review we focus on the pathophysiology of CRC-related pain and discuss currently applied pain management. Pain is a symptom reported by over 70 % of colorectal cancer (CRC) patients. It remains a feared and debilitating consequence of both cancer and cancer-related treatment. There are many options for pain management in CRC, consisting of intravenous, oral or topical medications. In order to address the full spectrum of pain, proper treatment should address the nociceptive, neuropathic and/or psychogenic pain component. Currently available methods do not bring pain relief to satisfying number of patients and, if used improperly, can cause a number of complications. Therefore, future treatments should focus primarily on alleviating pain, but also on reducing possible side effects. In this article we cover recent and promising pharmacological and non- pharmacological developments emerging in the field of CRC treatment.

Pain complications of oral implants: Is that an issue?

The use of oral implants as a form of replacing missing teeth in partial or total edentulous patients is considered the gold standard in oral rehabilitation. Although considered a history of success in contemporary dentistry, surgical complications may occur, as excessive bleeding, damage to the adjacent teeth and mandibular fractures. Persistent pain and abnormal somatosensory responses after the surgery ordinary healing time are also potential problems and may lead to the development of a condition named posttraumatic trigeminal neuropathic pain (PTNP). Though relatively rare, PTNP has a profound impact on patient's quality of life. Appropriated previous image techniques, effective anaesthetic procedures and caution during the surgical procedure and implant installation are recommended for the prevention of this condition. In case of the PTNP, different management modalities, including antidepressant and membrane stabilizer medications, as well as peripheral strategies, as the use of topical medication and the botulin toxin are presented and discussed.

Retinal teratogenicity of pregabalin in chick embryo model

BACKGROUND

Pregabalin is a gamma-aminobutyric acid analog that binds to the α2-δ subunits of the pre-synaptic voltage-dependent calcium channels of nerves with a high affinity and selectivity. In this study, the retinal teratogenic potential of pregabalin was investigated in a chick embryo model.

MATERIALS AND METHODS

Fertilised chicken eggs were divided into groups for administration with different doses of pregabalin. All eggs were opened on the 10th day of incubation. The embryos were dissected and the effects of pregabalin on the retina were investigated histopathologically, morphometrically, and immunohistochemically (Caspase-3).

RESULTS

There was no statistically significant difference between the low dose pregabalin, control, or vehicle control groups in terms of the number of retina layers and retinal thickness. Medium and high dose pregabalin caused a statistically significant decrease in the number of retina layers, as well as sensory retinal and pigment epithelium layer thicknesses. The outer nuclear and outer plexiform layer did not form in the group administered a medium dose. Similarly, the outer nuclear, outer plexiform, inner nuclear, and inner plexiform layer did not form in the high-dose group. No statistically significant difference was observed between the groups in terms of cellular damage and Caspase-3 expression.

CONCLUSION

The use of pregabalin during pregnancy compromises retinal development in a dose-dependent manner. The use of pregabalin in pregnancy causes the aforementioned defects in this system and it may have developmental effects that needs to be further evaluated.

Duloxetine hydrochloride loaded film forming dermal gel enriched with methylcobalamin and geranium oil attenuates paclitaxel-induced peripheral neuropathy in rats

Objective

In attempt to conquer the major concerns of oral duloxetine hydrochloride (like low bioavailability, intolerable side-effects and no regeneration of demyelinated nerve fibres) for the management of chemotherapy-induced peripheral neuropathy (CIPN), an alternative delivery of duloxetine hydrochloride was aimed for in-vivo optimization.

Methods

A film forming dermal gel consisting of duloxetine hydrochloride was formulated and enriched with methylcobalamin and geranium oil. The formulated gel successfully qualified the various pharmaceutical characteristics of gel. Administration of paclitaxel (8 mg/kg/i.p. in four divided doses) for 4 alternate days induced the symptoms of peripheral neuropathy in rats. On 14th day, the responses to noxious stimulus (mechanical hyperalgesia, cold allodynia, and heat hyperalgesia) were increased and reached to its maximum. Thereafter, drug treatment with formulated dermal gel and oral duloxetine hydrochloride (30 mg/kg, once daily) was initiated for 2 weeks in different group of animals. On the 28th day animals were sacrificed to isolate sciatic nerve, to assess biochemical changes (TBARS, reduced GSH, total protein, TNF-α, IL-6) and for histopathological examinations of nerve sections using Hematoxylin-Eosin and Toludine blue staining methods.

Results

Application of formulated dermal gel to paclitaxel-treated rats significantly improved paw-withdrawal latency responses during noxious stimulus testing, reduced the levels of TBARS, TNF-α, IL-6 and elevated the levels of reduced GSH as compared to paclitaxel treated rats. Histographs also indicated marked regeneration of the damaged nerve fibers. Topical delivery of duloxetine hydrochloride produced similar results in disparity to oral route. However, no significant disparity in responses was obtained with twice application of formulated dermal gel when compared to once daily application.

Conclusion

Tremendous recovery from nociception, oxidation and inflammation in addition to nerve degeneration was achieved through dermal application of duloxetine hydrochloride in peripheral neuropathy.

Sensory bedside testing: a simple stratification approach for sensory phenotyping

Supplemental Digital Content is Available in the Text.

Introduction:

Stratification of patients according to the individual sensory phenotype has been suggested a promising method to identify responders for pain treatment. However, many state-of-the-art sensory testing procedures are expensive or time-consuming.

Objectives:

Therefore, this study aimed to present a selection of easy-to-use bedside devices.

Methods:

In total, 73 patients (39 m/34 f) and 20 controls (11 m/9 f) received a standardized laboratory quantitative sensory testing (QST) and a bedside-QST. In addition, 50 patients were tested by a group of nonexperienced investigators to address the impact of training. The sensitivity, specificity, and receiver-operating characteristics were analyzed for each bedside-QST parameter as compared to laboratory QST. Furthermore, the patients' individual sensory phenotype (ie, cluster) was determined using laboratory QST, to select bedside-QST parameters most indicative for a correct cluster allocation.

Results:

The bedside-QST parameters “loss of cold perception to 22°C metal,” “hypersensitivity towards 45°C metal,” “loss of tactile perception to Q-tip and 0.7 mm CMS hair,” as well as “the allodynia sum score” indicated good sensitivity and specificity (ie, ≳70%). Results of interrater variability indicated that training is necessary for individual parameters (ie, CMS 0.7). For the cluster assessment, the respective bedside quantitative sensory testing (QST) parameter combination indicated the following agreements as compared to laboratory QST stratification: excellent for “sensory loss” (area under the curve [AUC] = 0.91), good for “thermal hyperalgesia” (AUC = 0.83), and fair for “mechanical hyperalgesia” (AUC = 0.75).

Conclusion:

This study presents a selection of bedside parameters to identify the individual sensory phenotype as cost and time efficient as possible.

Translational issues in precision medicine in neuropathic pain

Neuropathic pain remains poorly treated, with most new drugs falling through the translational gap. The traditional model of bench-to-bedside research has relied on identifying new mechanisms/targets in animal models and then developing clinical applications. Several have advocated bridging the translational gap by beginning with clinical observations and back-translating to animal models for further investigation of mechanisms. There is good evidence that phenotyping of patients through quantitative sensory testing can lead to improved treatment selection and hence improved patient outcomes. This practice has been widely adopted in clinical investigations, but its application in preclinical research is not mainstream. In this review, we retrospectively examine our historical rodent data sets with the aim of reconsidering drug effects on sensory neuronal endpoints, their alignment with clinical observations, and how these might guide future clinical studies.

The Association Between the Incidence Risk of Peripheral Neuropathy and PD-1/PD-L1 Inhibitors in the Treatment for Solid Tumor Patients: A Systematic Review and Meta-Analysis

Purpose: We conducted this study to determine the relationship between PD-1/PD-L1 inhibitors and the incidence risk of peripheral neuropathy in patients with solid tumors. Method: The process of the meta-analysis was performed by us according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Incidence of all-grade and grade 3-5 treatment-related peripheral neuropathy in patients with solid tumors were taken into account. Results: After screening and eligibility assessment, a total of 17 clinical trials involving 10,500 patients were selected for the final meta-analysis. The incidence risk of peripheral neuropathy for all grade was significantly lower in the PD-1/PD-L1 inhibitor group than that of the control group, either monotherapy (OR = 0.08, 95%CI:[0.03, 0.19]) or chemotherapy (OR = 0.05, 95%CI:[0.03, 0.11]). Similar incidence trend could also be seen for the incidence risk of grade 3-5 peripheral neuropathy. When PD-1/PD-L1 inhibitors were used in combination with chemotherapy, the incidence risk of peripheral neuropathy was higher than in the control chemotherapy group, whether it was all-grade (OR = 1.22, 95%CI:[1.00, 1.49]) or grade 3-5 degree (OR = 1.74, 95%CI:[1.03, 2.92]). Conclusion: Compared with chemotherapy, incidence risk of peripheral neuropathy related to PD-1/PD-L1 inhibitor was significantly lower than that of the chemotherapy group, while PD-1/PD-L1 inhibitor increased the incidence risk of peripheral neuropathy when it was combined with chemotherapy.