[Prevention of oxaliplatin-induced neuropathy by carbamazepine. A pilot study]

Ion Channel and Transporter Involvement in Chemotherapy-Induced Peripheral Neurotoxicity

The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids, proteasome inhibitors, thalidomide), the so-called chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN can be long-lasting or even permanent, and it is detrimental for the quality of life of cancer survivors, being associated with persistent disturbances such as sensory loss and neuropathic pain at limb extremities due to a mostly sensory axonal polyneuropathy/neuronopathy. In the state of the art, there is no efficacious preventive/curative treatment for this condition. Among the reasons for this unmet clinical and scientific need, there is an uncomplete knowledge of the pathogenetic mechanisms. Ion channels and transporters are pivotal elements in both the central and peripheral nervous system, and there is a growing body of literature suggesting that they might play a role in CIPN development. In this review, we first describe the biophysical properties of these targets and then report existing data for the involvement of ion channels and transporters in CIPN, thus paving the way for new approaches/druggable targets to cure and/or prevent CIPN.

Chemotherapy-induced peripheral neuropathy in children and adolescent cancer patients

Brain cancer and leukemia are the most common cancers diagnosed in the pediatric population and are often treated with lifesaving chemotherapy. However, chemotherapy causes severe adverse effects and chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting and debilitating side effect. CIPN can greatly impair quality of life and increases morbidity of pediatric patients with cancer, with the accompanying symptoms frequently remaining underdiagnosed. Little is known about the incidence of CIPN, its impact on the pediatric population, and the underlying pathophysiological mechanisms, as most existing information stems from studies in animal models or adult cancer patients. Herein, we aim to provide an understanding of CIPN in the pediatric population and focus on the 6 main substance groups that frequently cause CIPN, namely the vinca alkaloids (vincristine), platinum-based antineoplastics (cisplatin, carboplatin and oxaliplatin), taxanes (paclitaxel and docetaxel), epothilones (ixabepilone), proteasome inhibitors (bortezomib) and immunomodulatory drugs (thalidomide). We discuss the clinical manifestations, assessments and diagnostic tools, as well as risk factors, pathophysiological processes and current pharmacological and non-pharmacological approaches for the prevention and treatment of CIPN.

Bee Venom Acupuncture Attenuates Oxaliplatin-Induced Neuropathic Pain by Modulating Action Potential Threshold in A-Fiber Dorsal Root Ganglia Neurons

Oxaliplatin is a third-generation platinum-based chemotherapeutic drug widely used in colorectal cancer treatment. Although potent against this tumor, it can induce cold and mechanical allodynia even after a single injection. The currently used drugs to attenuate this allodynia can also cause unwanted effects, which limit their use. Bee venom acupuncture (BVA) is widely used in Korean medicine to treat pain. Although the effect of BVA on oxaliplatin-induced neuropathic pain has been addressed in many studies, its action on dorsal root ganglia (DRG) neurons has never been investigated. A single oxaliplatin injection (6 mg/kg, intraperitoneally) induced cold and mechanical allodynia, and BVA (0.1 and 1 mg/kg, subcutaneous, ST36) dose-dependently decreased allodynia in rats. On acutely dissociated lumbar 4-6 DRG neurons, 10 min application of oxaliplatin (100 μM) shifted the voltage-dependence of sodium conductance toward negative membrane potentials in A- but not C-fibers. The resting membrane potential remained unchanged, but the action potential threshold decreased significantly compared to that of the control (p < 0.05). However, 0.1 μg/mL of BVA administration increased the lowered action potential threshold. In conclusion, these results suggest that BVA may attenuate oxaliplatin-induced neuropathic pain by altering the action potential threshold in A-fiber DRG neurons.

Effect of Oxaliplatin on Voltage-Gated Sodium Channels in Peripheral Neuropathic Pain

Oxaliplatin is a chemotherapeutic drug widely used to treat various types of tumors. However, it can induce a serious peripheral neuropathy characterized by cold and mechanical allodynia that can even disrupt the treatment schedule. Since the approval of the agent, many laboratories, including ours, have focused their research on finding a drug or method to decrease this side effect. However, to date no drug that can effectively reduce the pain without causing any adverse events has been developed, and the mechanism of the action of oxaliplatin is not clearly understood. On the dorsal root ganglia (DRG) sensory neurons, oxaliplatin is reported to modify their functions, such as the propagation of the action potential and induction of neuropathic pain. Voltage-gated sodium channels in the DRG neurons are important, as they play a major role in the excitability of the cell by initiating the action potential. Thus, in this small review, eight studies that investigated the effect of oxaliplatin on sodium channels of peripheral neurons have been included. Its effects on the duration of the action potential, peak of the sodium current, voltage–response relationship, inactivation current, and sensitivity to tetrodotoxin (TTX) are discussed.

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.

New Insights into Potential Prevention and Management Options for Chemotherapy-Induced Peripheral Neuropathy

OBJECTIVE

Neurological complications such as chemotherapy-induced peripheral neuropathy (CIPN) and neuropathic pain are frequent side effects of neurotoxic chemotherapy agents. An increasing survival rate and frequent administration of adjuvant chemotherapy treatments involving neurotoxic agents makes it imperative that accurate diagnosis, prevention, and treatment of these neurological complications be implemented.

METHODS

A consideration was undertaken of the current options regarding protective and treatment interventions for patients undergoing chemotherapy with neurotoxic chemotherapy agent or experience with CIPN. Current knowledge on the mechanism of action has also been identified. The following databases PubMed, the Cochrane Library, Science Direct, Scopus, EMBASE, MEDLINE, CINAHL, CNKI, and Google Scholar were searched for relevant article retrieval.

RESULTS

A range of pharmaceutical, nutraceutical, and herbal medicine treatments were identified that either showed efficacy or had some evidence of efficacy. Duloxetine was the most effective pharmaceutical agent for the treatment of CIPN. Vitamin E demonstrated potential for the prevention of cisplatin-IPN. Intravenous glutathione for oxaliplatin, Vitamin B6 for both oxaliplatin and cisplatin, and omega 3 fatty acids for paclitaxel have shown protection for CIPN. Acetyl-L-carnitine may provide some relief as a treatment option. Acupuncture may be of benefit for some patients and Gosha-jinki-gan may be of benefit for protection from adverse effects of oxaliplatin induced peripheral neuropathy.

CONCLUSIONS

Clinicians and researchers acknowledge that there are numerous challenges involved in understanding, preventing, and treating peripheral neuropathy caused by chemotherapeutic agents. New insights into mechanisms of action from chemotherapy agents may facilitate the development of novel preventative and treatment options, thereby enabling medical staff to better support patients by reducing this debilitating side effect.

Oxaliplatin-induced neurotoxicity is mediated through gap junction channels and hemichannels and can be prevented by octanol

Oxaliplatin-induced neurotoxicity (OIN) is a common complication of chemotherapy without effective treatment. In order to clarify the mechanisms of both acute and chronic OIN, we used an ex-vivo mouse sciatic nerve model. Exposure to 25 μM oxaliplatin caused a marked prolongation in the duration of the nerve evoked compound action potential (CAP) by nearly 1200% within 300 min while amplitude remained constant for over 20 h. This oxaliplatin effect was almost completely reversed by the gap junction (GJ) inhibitor octanol in a concentration-dependent manner. Further GJ blockers showed similar effects although with a narrower therapeutic window. To clarify the target molecule we studied sciatic nerves from connexin32 (Cx32) and Cx29 knockout (KO) mice. The oxaliplatin effect and neuroprotection by octanol partially persisted in Cx29 better than in Cx32 KO nerves, suggesting that oxaliplatin affects both, but Cx32 GJ channels more than Cx29 hemichannels. Oxaliplatin also accelerated neurobiotin uptake in HeLa cells expressing the human ortholog of Cx29, Cx31.3, as well as dye transfer between cells expressing the human Cx32, and this effect was blocked by octanol. Oxaliplatin caused no morphological changes initially (up to 3 h of exposure), but prolonged nerve exposure caused juxtaparonodal axonal edema, which was prevented by octanol. Our study indicates that oxaliplatin causes forced opening of Cx32 channels and Cx29 hemichannels in peripheral myelinated fibers leading to disruption of axonal K(+) homeostasis. The GJ blocker octanol prevents OIN at very low concentrations and should be further studied as a neuroprotectant.

Taxane induced neuropathy in patients affected by breast cancer: Literature review

Taxane induced neuropathy (TIN) is the most limiting side effect of taxane based chemotherapy, relative to the majority of breast cancer patients undergoing therapy with both docetaxel and paclitaxel. The symptoms begin symmetrically from the toes, because the tips of the longest nerves are affected for first. The patients report sensory symptoms such as paresthesia, dysesthesia, numbness, electric shock-like sensation, motor impairment and neuropathic pain. There is a great inter-individual variability among breast cancer women treated with taxanes, in fact 20-30% of them don't develop neurotoxicity. Actually, there is no standard therapy for TIN, although many medications, antioxidants and natural substances have been tested in vitro and in vivo. We will summarize all most recent literature data on TIN prevention and treatment, in order to reach an improvement in TIN management. Further studies are needed to evaluate new therapies that restore neuronal function and improve life quality of patients.

Chemotherapy-Induced Peripheral Neuropathy in Pediatric Cancer Patients

Chemotherapy-induced peripheral neuropathies (CIPNs) are an increasingly common neuropathic and pain syndrome in adult and pediatric cancer patients and survivors [1-69]. However, symptoms associated with CIPNs are often undiagnosed, under-assessed, and communications problems between clinicians, family members, and patients have been observed [70-73]. Less is known about the prevalence and impact of CIPNs on pediatric cancer populations [70-71]. This article aims to provide a brief understanding of CIPNs in pediatric populations, and to review the evidence for both its prevention and treatment.

Effects of calcium and magnesium on acute and chronic neurotoxicity caused by oxaliplatin: A meta-analysis

The primary toxicity of oxaliplatin is neurotoxicity. Calcium and magnesium (Ca/Mg) are reported to be beneficial in protecting against this adverse effect. However, the results obtained from clinical trials are not definitive. The aim of this study was to evaluate whether Ca/Mg alleviates the neurotoxicity of oxaliplatin by performing a meta-analysis of the literature involving available randomized controlled trials. Systematic searches for trials were undertaken from the Cochrane Library, MEDLINE, CENTRAL, Embase, CBMdisc and CNKI databases without language limitations. The primary outcome was severe chronic neurotoxicity and the secondary outcome was acute neurotoxicity. Four randomized double-blind trials met the search criteria. The odds ratio (OR) comparing Ca/Mg treatment with placebo was 0.44 (0.23–0.85, P=0.01) for severe chronic neurotoxicity of oxaliplatin (grade ≥2) and 0.41 (0.11–1.49, P=0.18) for acute neurotoxicity. In conclusion, Ca/Mg treatment does not reduce the incidence of acute neurotoxicity of oxaliplatin, but does reduce the incidence of severe chronic neurotoxicity (grade ≥2). No differences were observed in the outcomes of chemotherapy. Thus, Ca/Mg treatment is recommended for use as an adjunct with oxaliplatin.

Clinical pattern and associations of oxaliplatin acute neurotoxicity: a prospective study in 170 patients with colorectal cancer

BACKGROUND

The objective of the current prospective, multicenter, international study was to trace the incidence and severity of acute oxaliplatin-induced peripheral neuropathy (OXLIPN) and to determine its clinical pattern. The authors also specifically tested whether patients who had more symptoms of acute OXLIPN eventually would develop a more severe chronic, cumulative form of OXLIPN.

METHODS

One hundred seventy patients (mean ± standard deviation age, 63.7 ± 8.7 years) who were scheduled to receive either combined leucovorin, 5-fluoruracil, and oxaliplatin (FOLFOX) or combined capecitabine and oxaliplatin (XELOX) for metastatic colorectal cancer were monitored prospectively at baseline and were followed in 4 European sites. The incidence of hyperexcitability symptoms secondary to acute OXLIPN was assessed by using a descriptive questionnaire (yes/no question) at each clinical evaluation. Motor and neurosensory criteria according to version 3 of the National Cancer Institute's Common Toxicity Criteria were applied to clinically grade the severity of OXLIPN.

RESULTS

Acute OXLIPN was present in 146 of 170 patients (85.9%). The vast majority of these patients manifested cold-induced perioral (95.2%) or pharyngolaryngeal (91.8%) dysesthesias. Severe acute OXLIPN that required prolongation of oxaliplatin infusion from 2 hours to 4 to 6 hours occurred in 32 of 146 patients (21.9%). The increased number of acute OXLIPN symptoms was correlated significantly (Spearman rho correlation coefficient [r]) with both the development (r = 0.602; P < .001) and the degree of the chronic, cumulative form (r = 0.702; P < .001).

CONCLUSIONS

The current results indicated that the vast majority of patients with colorectal cancer who receive oxaliplatin-based chemotherapy will manifest symptoms of a transient acute syndrome soon after oxaliplatin administration. Patients who have a more complex combination of acute phenomena related to axonal hyperexcitability are those who eventually develop more severe OXLIPN. Therefore, it may be advisable to test agents against acute OXLIPN to verify their effects on the chronic form.

Objective evaluation of the alleviating effects of Goshajinkigan on peripheral neuropathy induced by paclitaxel/carboplatin therapy: A multicenter collaborative study

Paclitaxel/carboplatin chemotherapy for cancer (TC therapy) exhibits neurotoxicity and causes peripheral neuropathy at a high frequency, which is difficult to cope with. In this study, we investigated the efficacy of Goshajinkigan, a traditional Japanese herbal medicine, for TC therapy-induced peripheral neuropathy. The subjects included in our study were patients with ovarian or endometrial cancer who underwent TC therapy and developed peripheral neuropathy. The patients were randomly divided into Group A, comprising of 14 patients (vitamin B12 treatment), and Group B, comprising of 15 patients (vitamin B12 + Goshajinkigan treatment). The observation period was 6 weeks following treatment initiation, and the evaluation items were as follows: i) the current perception threshold (CPT value) of the peripheral nerve, ii) visual analogue scale for numbness, iii) National Cancer Institute Common Terminology Criteria for Adverse Events v3.0 grade of neurotoxicity, and iv) a questionnaire on the subjective symptoms of peripheral neuropathy (functional assessment of cancer therapy-taxane). These were compared between the groups and no significant differences were noted in any item. However, CTCAE grade 3 neurotoxicity developed in 2 patients (14.3%) after 6 weeks of administration in Group A, whereas no neurotoxicity was observed in Group B. When the change in the frequency of abnormal CPT ratio at 6 weeks of administration from that before treatment was compared between the groups, the frequency of abnormal value was significantly lower in Group B than in Group A (p<0.05). This suggests that Goshajinkigan inhibits the progression of peripheral neuropathy.

Pyridoxine to protect from oxaliplatin-induced neurotoxicity without compromising antitumour effect

PURPOSE

Oxaliplatin (OHP) in combination with 5-fluorouracil/leucovorin (FOLFOX) is clinically used as frontline therapy in patients with advanced colorectal carcinoma (CRC), with response rates ranging from 46 to 71%. This combination is now considered a standard treatment for metastatic CRC and also in the post-operative adjuvant setting. Reversible, cumulative, peripheral sensory neuropathy is the principal dose-limiting toxicity of OHP therapy. Pyridoxine (vitamin B6) has been shown to reduce cisplatin and fluoropyrimidine-related neurotoxicity but its administration with OHP has not yet been studied. Low doses of pyridoxine are free of side effects; it can be given orally. If pyridoxine administration with oxaliplatin has no adverse effect on OHP cytotoxicity effects, it will be a simple and cost-effective way to minimise OHP-induced neurotoxicity.

METHODS

In vitro simultaneous combination of OHP and pyridoxine was studied in 6 CRC cell lines (HT29, Widr, SW480, HCT116, H630 and SW1116), in an ovarian cancer cell line (A2780) and its cisplatin-resistant subline (ADDP) and in an oestrogen-dependent breast cancer cell line (MCF-7). Three fixed concentrations of pyridoxine: 1, 10 and 25 μM were combined with varying concentrations of OHP, and the growth inhibitory effects were evaluated using the MTT cell growth assay.

RESULTS

Oxaliplatin induced consistent cytotoxicity in all cell lines with GI(50) values between 0.23 and 7.6 μM. Addition of pyridoxine at concentrations of 1-25 μM does not affect OHP cytotoxicity.

CONCLUSIONS

Administration of pyridoxine, at concentrations extending across possible therapeutic plasma levels in humans, does not antagonise OHP antitumour effects in a range of relevant tumour cell lines. This study provides a foundation for clinical studies to test whether pyridoxine can minimise OHP-related neurotoxicity, and clinicians can be confident that pyridoxine is very unlikely to reverse the antitumour effects of OHP, as seems to be the case with Ca/Mg infusions. This could prove to be a cost-effective way to minimise OHP-related neurotoxicity, allowing more effective less toxic treatment and better outcomes in patients.

Oxaliplatin-based chemotherapy in the management of colorectal cancer

Oxaliplatin is the only third-generation platinum derivative compound that has found a place in the routine treatment of colorectal cancer (CRC). The appearance of oxaliplatin, as well as irinotecan, in the CRC treatment armamentarium has offered new standards for adjuvant treatment and greater hopes in metastatic disease. Moreover, the combination of oxaliplatin-based chemotherapy with new targeted drugs has improved response rates and survival of these patients. Despite these new approaches, the prognosis of CRC remains poor and a better understanding of the molecular pathways is needed to optimize the use of these new approaches. In this review, the authors examine the development of oxaliplatin as well as the main trials that have positioned oxaliplatin as a key drug in the treatment of CRC.

The effects of oxaliplatin, an anticancer drug, on potassium channels of the peripheral myelinated nerve fibres of the adult rat

Oxaliplatin is a novel chemotherapeutic agent which is effective against advanced colorectal cancer, but at the same time causes severe neuropathy in the peripheral nerve fibres, affecting mainly the voltage-gated sodium (Na(+)) channels (VGNaCs), according to literature. In this study the effects of oxaliplatin on the peripheral myelinated nerve fibres (PMNFs) were investigated in vitro using the isolated sciatic nerve of the adult rat. The advantage of this nerve-preparation was that stable in amplitude evoked compound action potentials (CAP) were recorded for over 1000min. Incubation of the sciatic nerve fibres in 25, 100 and 500microM oxaliplatin, for 300-700min caused dramatic distortion of the waveform of the CAP, namely broadening the repolarization phase, repetitive firing and afterhyperpolarization (AHP), related to the malfunction of voltage-gated potassium (K(+)) channels (VGKCs). At a concentration of 5microM, oxaliplatin caused broadening of the repolarization phase of the CAP only, while the no observed effect concentration was estimated to be 1microM. These findings are indicative of severe effects of oxaliplatin on the VGKCs. In contrast, the amplitude and the rise-time of the depolarization of the CAP did not change significantly, a clear indication that the VGNaCs of the particular nerve preparation were not affected by oxaliplatin. The effects of oxaliplatin on the PMNFs were similar to those of 4-aminopyridine (4-AP), a classical antagonist of VGKCs. These similarities in the pattern of action between oxaliplatin and 4-AP combined with the fact that the effects of oxaliplatin were more pronounced and developed at lower concentrations suggest that oxaliplatin acts as a potent VGKCs antagonist.

A review on oxaliplatin-induced peripheral nerve damage

Platinum compounds are a class of chemotherapy agents that posses a broad spectrum of activity against several solid malignancies. Oxaliplatin (OXL) is a third-generation organoplatinum compound with significant activity mainly against colorectal cancer (CRC). Peripheral neuropathy is a well recognized toxicity of OXL, usually resulting in dose modification. OXL induces two types of peripheral neuropathy; acute and chronic. The acute oxaliplatin-induced peripheral neuropathy (OXLIPN) may be linked to the rapid chelation of calcium by OXL-induced oxalate and OXL is capable of altering the voltage-gated sodium channels through a pathway involving calcium ions. On the other hand, decreased cellular metabolism and axoplasmatic transport resulting from the accumulation of OXL in the dorsal root ganglia cells is the most widely accepted mechanism of chronic oxaliplatin-induced peripheral neuropathy (OXLIPN). As a result, OXL produces a symmetric, axonal, sensory distal primary neuronopathy without motor involvement. The incidence of OXLIPN is usually related to various risk factors, including treatment schedule, dosage, cumulative dose and time of infusion. The assessment of OXLIPN is primarily based on neurologic clinical examination and quantitative methods, such as nerve conduction study. To date, several neuroprotective agents including thiols, neurotrophic factors, anticonvulsants and antioxidants have been tested for their ability to prevent OXLIPN. However, the clinical data are still controversial. We herein review and discuss the pathogenesis, incidence, risk factors, diagnosis, characteristics and management of OXLIPN. We also highlight areas of future research.

Putting evidence into practice: evidence-based interventions for chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) continues to be a significant, debilitating symptom resulting from the administration of neurotoxic chemotherapy for the treatment of cancer. CIPN is an important consequence of cancer treatment because of its potential impact on physical functioning and quality of life. Oncology nurses play an important role in assessing, monitoring, and educating clients about CIPN. Despite investigations concerning pharmacologic and nonpharmacologic approaches to either preventing or minimizing the neurotoxicity resulting from certain chemotherapeutic agents, evidence to support the interventions is lacking. This article presents information concerning CIPN and summarizes the evidence for pharmacologic and nonpharmacologic approaches to the prevention and treatment of CIPN.

Schmerzhaftes Hyperexzitabilitätssyndrom unter Oxaliplatin-haltiger Chemotherapie

The platinum derivative oxaliplatin is widely used in colorectal cancer. Its side effects differ from those of the other platinum compounds cisplatin and carboplatin. An acute, painful hyperexcitability syndrome (HES) accompanied by cold induced paresthesia, dysesthesia and myotonia is unique to oxaliplatin, whereas a chronic, peripheral sensory neuropathy (PSN) can be caused by all platinum compounds. It is believed that HES is the result of peripheral nerve hyperexcitability as a consequence of voltage-gated sodium channel dysfunction, which may be caused by calcium level imbalance. Therapeutic options for HES are the administration of calcium and magnesium, the serotonin and noradrenaline reuptake inhibitor (SNRI) venlafaxine and the thiophosphate amifostine.

Neuroprotection during chemotherapy: a systematic review

The development of neurotoxicity during antineoplastic therapy is one of the most common reasons for termination or modification of cancer treatment. A number of different agents have been proposed to provide neuroprotection without affecting antitumor efficacy. This review provides an evidence-based summary of neuroprotective medicines, an overview of the literature relating to neuroprotection during cancer treatment and a Neurologist perspective risk assessment and management. Through a systematic review the authors identified 49 papers published to date that report human clinical trials involving potential neuroprotectants in adults. Case reports and series completed in a prospective fashion were also included. Sensory neuropathies were the most prevalent subtype in the literature, and most were at least partially reversible with or without neuroprotective treatment. The majority of study medications had minimal side effects, though 2 trials were prematurely terminated because of adverse patient outcomes. No study reported an effect on antitumor efficacy. Because of the variability in study design, cancer type, outcome measures, and clinical confirmation of neuropathy, meta-analysis could not be appropriately performed. We highlight risk factors and discuss neuropathy screening. Descriptive analysis is provided which reveals that many of the agents studied were likely to confer some at least some neuroprotective benefit.

Carbamazepine for prevention of oxaliplatin-related neurotoxicity in patients with advanced colorectal cancer: Final results of a randomised, controlled, multicenter phase II study

BACKGROUND

Oxaliplatin-induced neurotoxicity is a growing, relevant clinical problem. In this study we evaluated the efficacy and safety of carbamazepine for prevention of oxaliplatin-associated neuropathy in patients with advanced colorectal cancer.

METHODS

Chemotherapeutic treatment consisted of oxaliplatin 85 mg/m(2) given biweekly and weekly folinic acid 500 mg/m(2) followed by a 24-h infusion of 5-FU 2000 mg/m(2) (FUFOX). One cycle consisted of six consecutive weeks of treatment followed by two weeks of rest (=Treatment B). For Treatment A carbamazepine was added in a dosage for targeted plasma levels of 4-6 mg/L. Neurotoxicity was regularly assessed using a specific scale. Moreover, an evaluation of chronic sensory symptoms and a neurologic examination including tests for vibrational sense, strength and deep tendon reflexes were added creating a peripheral neuropathy (PNP) score.

RESULTS

The prospectively defined adequate number of patients needed to provide power for the primary outcome could not be achieved. 19 patients were assigned to Treatment A and 17 to Treatment B. At baseline, the distribution of all clinicopathologic variables was comparable between the two groups. Overall response rates were 16% and 24% and overall survival 15.1 months and 17.4 months for Treatment A and Treatment B, respectively. Between Treatment A and Treatment B there were no major differences when considering worst neurotoxicity during the study period (p=0.46). Grade 3/4 neurotoxicity occured in 4 patients with Treatment A vs. 6 patients with Treatment B. There were no major differences between both groups in each category of the PNP score.

CONCLUSIONS

Based on the small number of patients and low statistical power of our study definite conclusions regarding efficacy and safety of carbamazepine for prevention of oxaliplatin-associated neuropathy in patients with advanced colorectal cancer cannot be drawn.

Oxaliplatin-related neurotoxicity: how and why?

In early clinical trials, oxaliplatin has demonstrated significant activity against colorectal cancer in combination with 5-fluorouracil (5-FU) and folinic acid (FA), both in metastatic as in radically resected disease. The drug differs from the other two most important platinum compounds (cisplatin and carboplatin) for the absence of nephrotoxicity or for the reduced drug-induced ototoxicity. During its administration, two different types of neurological symptoms can be experienced: the first one occurs during or immediately after the end of the infusion and it appears as a transient peripheral sensory neuropathy manifesting as paresthesias and dysesthesia in the extremities sometimes accompanied by muscular contractions of the extremities or the jaw (triggered or enhanced by exposure to cold). The second one occurs after long-term administration of oxaliplatin presenting with deep sensory loss, sensory ataxia and functional impairment (similar to those observed with cisplatin). This type of neurotoxicity is usually late-onset and correlated with the cumulative-dose of oxaliplatin. The aim of this review is to analyse the mechanism underlying induction of neurotoxicity and the possible treatments to prevent and to treat it.

Clinical management of oxaliplatin-associated neurotoxicity

In recent years, oxaliplatin-based chemotherapy protocols, particularly oxaliplatin in combination with infusional 5-fluorouracil/leucovorin (FOLFOX or FUFOX), have emerged as the standard of care in first- and second-line therapy of advanced-stage colorectal cancer. Although oxaliplatin by itself has only mild hematologic and gastrointestinal side effects, its clinically dominating toxicity affects the peripheral sensory nervous system in the form of 2 distinct types of neurotoxicity: (1) a unique, frequent, acute sensory neuropathy that is triggered or aggravated by exposure to cold but at the same time is rapidly reversible without persistent impairment of sensory functions; (2) the dose-limiting toxicity of oxaliplatin, a cumulative, chronic sensory neurotoxicity that resembles that of cisplatin with the important difference of its being more rapidly and completely reversible. This chronic sensory neurotoxicity is highly predictable, being closely associated with the cumulative dose of oxaliplatin that is administered. Various strategies have been proposed to prevent or treat oxaliplatin-induced neurotoxicity. The stop-and-go concept uses the predictability and reversibility of neurologic symptoms to allow patients to stay on an oxaliplatin-containing first-line therapy for a prolonged period. Several neuromodulatory agents such as calcium-magnesium infusions; antiepileptic drugs like carbamazepine, gabapentin, and venlafaxine; amifostine; a-lipoic acid; and glutathione have demonstrated some activity in the prophylaxis and treatment of oxaliplatin-induced acute neuropathy. However, randomized trials demonstrating a prophylactic or therapeutic effect on oxaliplatin's cumulative neurotoxicity are still lacking. The predictability of neurotoxicity associated with oxaliplatin-based therapy should allow patients and doctors to develop strategies to manage this side effect in view of the individual patient's clinical situation. This is of increasing importance, because the addition of bevacizumab to FOLFOX will conceivably further prolong the progression-free survival achieved with FOLFOX so that neurotoxicity and not tumor progression could become the dominating treatment-limiting issue in the first-line therapy of advanced colorectal cancer.

A review of oxaliplatin and its clinical use in colorectal cancer

Colorectal cancer is one of the leading causes of death from malignant diseases in the Western world. Worldwide, approximately 50% of patients who present with colorectal cancer will develop metastatic disease and eventually die from this malignancy. Recently, significant advances have been made in the medical treatment of advanced colorectal cancer with the introduction of novel cytotoxic drugs, such as irinotecan and oxaliplatin. Based on the results of recent Phase III trials, combination regimens of infusional 5-fluorouracil/leucovorin and oxaliplatin (FOLFOX) have emerged as a new standard of care in the palliative and adjuvant treatment of colorectal cancer. The addition of biological agents targeting angiogenesis or oncogenes such as epidermal growth factor receptor (EGFR) to FOLFOX will conceivably further enhance the activity of treatment regimens. Making use of all available active therapeutic options in the course of disease has significantly improved median overall survival of metastatic colorectal cancer into a chronic disease, with implications for treatment strategies and pharmacoeconomic considerations.

Chemotherapy-induced peripheral neurotoxicity

Chemotherapy-induced peripheral neurotoxicity (CIPN) is a major clinical problem because it represents the dose-limiting side effects of a significant number of antineoplastic drugs. The incidence of CIPN varies depending on the drugs and schedules used, and this can be quite high, particularly when neurophysiological methods are used to make a diagnosis. However, even when CIPN is not a dose-limiting side effect, its onset may severely affect the quality of life of cancer patients and cause chronic discomfort. In this review the features of CIPN due to the administration of the most widely used drugs, such as platinum drugs, taxanes and vinca alkaloids, and of two old drugs with new clinical applications, suramin and thalidomide, will be discussed. Moreover, the earliest data regarding the neurotoxicity of some new classes of very promising antineoplastic agents, such as epothilones and proteasome inhibitors, will be discussed. Finally, the data available on neuroprotectants, evaluated in the attempt to prevent CIPN, will be summarised.

Oxaliplatin reintroduction in patients previously treated with leucovorin, fluorouracil and oxaliplatin for metastatic colorectal cancer

BACKGROUND

FOLFOX, a bimonthly combination of leucovorin, 5-fluorouracil and oxaliplatin, is active in metastatic colorectal cancer, but sometimes causes cumulative sensory neurotoxicity. This retrospective study investigated FOLFOX reintroduction after a break in treatment or following disease progression on another regimen.

PATIENTS AND METHODS

FOLFOX was reintroduced in 29 patients. During their previous FOLFOX therapy, 24 had achieved a response, four were stable and one had progression. Median progression-free survival (PFS) was 33 weeks. Grade 3 neuropathy developed in nine and grade 2 neuropathy in eight patients.

RESULTS

Following FOLFOX reintroduction, six patients (21%) showed a response, 15 (52%) were stable and eight (28%) had progression. Median PFS was 18 weeks. Grade 3 neuropathy developed in four patients and grade 2 neuropathy in 11. Two patients with previous grade 3 neuropathy had no recurrence of neuropathy after eight and 18 cycles, respectively. Among 13 patients who received no treatment between periods of FOLFOX therapy, four (31%) had a response and eight (62%) had stable disease.

CONCLUSION

Reintroduction of oxaliplatin was feasible and achieved a response or stabilization in 73% of patients. These results support the concept of intensified, repeated short courses of FOLFOX, a strategy currently being evaluated prospectively in the OPTIMOX study.

Prevention of Oxaliplatin-Related Neurotoxicity by Calcium and Magnesium Infusions

PURPOSE

Oxaliplatin is active in colorectal cancer. Sensory neurotoxicity is its dose-limiting toxicity. It may come from an effect on neuronal voltage-gated Na channels, via the liberation one its metabolite, oxalate. We decided to use Ca and Mg as oxalate chelators.

EXPERIMENTAL DESIGN

A retrospective cohort of 161 patients treated with oxaliplatin + 5-fluorouracil and leucovorin for advanced colorectal cancer, with three regimens of oxaliplatin (85 mg/m(2)/2w, 100/2w, 130/3w) was identified. Ninety-six patients received infusions of Ca gluconate and Mg sulfate (1 g) before and after oxaliplatin (Ca/Mg group) and 65 did not.

RESULTS

Only 4% of patients withdrew for neurotoxicity in the Ca/Mg group versus 31% in the control group (P = 0.000003). The tumor response rate was similar in both groups. The percentage of patients with grade 3 distal paresthesia was lower in Ca/Mg group (7 versus 26%, P = 0.001). Acute symptoms such as distal and lingual paresthesia were much less frequent and severe (P = 10(-7)), and pseudolaryngospasm was never reported in Ca/Mg group. At the end of the treatment, 20% of patients in Ca/Mg group had neuropathy versus 45% (P = 0.003). Patients with grade 2 and 3 at the end of the treatment in the 85 mg/m(2) oxaliplatin group recovered significantly more rapidly from neuropathy than patients without Ca/Mg.

CONCLUSIONS

Ca/Mg infusions seem to reduce incidence and intensity of acute oxaliplatin-induced symptoms and might delay cumulative neuropathy, especially in 85 mg/m(2) oxaliplatin dosage.

Oxaliplatin-induced neurotoxicity: acute hyperexcitability and chronic neuropathy

Oxaliplatin, a platinum-based chemotherapeutic agent, is effective in the treatment of solid tumors, particularly colorectal cancer. During and immediately following oxaliplatin infusion, patients may experience cold-induced paresthesias, throat and jaw tightness, and occasionally focal weakness. We assessed nerve conduction studies and findings on needle electromyography of patients with metastatic colorectal cancer before and during treatment with oxaliplatin. Twenty-two patients had follow-up studies within 48 h following oxaliplatin infusions, and 14 patients had follow-up studies after 3-9 treatment cycles. Repetitive compound muscle action potentials and neuromyotonic discharges were observed in the first 24-48 h following oxaliplatin infusion, but resolved by 3 weeks. After 8-9 treatment cycles, sensory nerve action potential amplitudes declined, without conduction velocity changes or neuromyotonic discharges. The acute neurological symptoms reflect a state of peripheral nerve hyperexcitability that likely represents a transient oxaliplatin-induced channelopathy. Chronic treatment causes an axonal neuropathy similar to other platinum-based chemotherapeutic agents.

Neurotoxic complications of chemotherapy in patients with cancer: clinical signs and optimal management

Neurotoxic side effects of chemotherapy occur frequently and are often a reason to limit the dose of chemotherapy. Since bone marrow toxicity, as the major limiting factor in most chemotherapeutic regimens, can be overcome with growth factors or bone marrow transplantation, the use of higher doses of chemotherapy is possible, which increases the risk of neurotoxicity. Chemotherapy may cause both peripheral neurotoxicity, consisting mainly of a peripheral neuropathy, and central neurotoxicity, ranging from minor cognitive deficits to encephalopathy with dementia or even coma. In this article we describe the neurological adverse effects of the most commonly used chemotherapeutic agents. The vinca-alkaloids, cisplatin and the taxanes are amongst the most important drugs inducing peripheral neurotoxicity. These drugs are widely used for various malignancies such as ovarian and breast cancer, and haematological cancers. Chemotherapy-induced neuropathy is clearly related to cumulative dose or dose-intensities. Patients who already have neuropathic symptoms due to diabetes mellitus, hereditary neuropathies or earlier treatment with neurotoxic chemotherapy are thought to be more vulnerable for the development of chemotherapy-induced peripheral neuropathy. Methotrexate, cytarabine (cytosine arabinoside) and ifosfamide are primarily known for their central neurotoxic side effects. Central neurotoxicity ranges from acute toxicity such as aseptic meningitis, to delayed toxicities comprising cognitive deficits, hemiparesis, aphasia and progressive dementia. Risk factors are high doses, frequent administration and radiotherapy preceding methotrexate chemotherapy, which appears to be more neurotoxic than methotrexate as single modality. Data on management and neuroprotective agents are discussed. Management mainly consists of cumulative dose-reduction or lower dose-intensities, especially in patients who are at higher risk to develop neurotoxic side effects. None of the neuroprotective agents described in this article can be recommended for standard use in daily practise at this moment, and further studies are needed to confirm some of the beneficial effects described.

Toxicity of platinum compounds

Since the introduction of platinum-based combination chemotherapy, particularly cisplatin, the outcome of the treatment of many solid tumours has changed. The leading platinum compounds in cancer chemotherapy are cisplatin, carboplatin and oxaliplatin. They share some structural similarities; however, there are marked differences between them in therapeutic use, pharmacokinetics and adverse effects profiles [1-4]. Compared to cisplatin, carboplatin has inferior efficacy in germ-cell tumour, head and neck cancer and bladder and oesophageal carcinoma, whereas both drugs seem to have comparable efficacy in advanced non-small cell and small cell lung cancer as well as ovarian cancer [5-7]. Oxaliplatin belongs to the group of diaminocyclohexane platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid [8,9]. Other platinum compounds such as oral JM216, ZD0473, BBR3464 and SPI-77, which is a pegylated liposomal formulation of cisplatin, are still under investigation [10-13], whereas nedaplatin has been approved in Japan for the treatment of non-small cell lung cancer and other solid tumours. This review focuses on cisplatin, carboplatin and oxaliplatin.

Prevention of oxaliplatin-induced peripheral sensory neuropathy by carbamazepine in patients with advanced colorectal cancer

Oxaliplatin plays a key role in the treatment of advanced colorectal cancer. The dose-limiting side effect of this platinum analogue is neurotoxicity. Significant efforts have been undertaken in an attempt to prevent and/or circumvent the development of neurotoxicity. Sodium channel inactivation kinetics on rat sensory sural nerve preparations are altered after exposure to oxaliplatin. Carbamazepine antagonizes this effect in vitro. Results from preliminary clinical studies indicate that the sodium channel blockers carbamazepine and gabapentin may be effective in preventing neurotoxicity. The role of amifostine is not yet clear. Randomized clinical studies are necessary to confirm the potential benefit of carbamazepine and other sodium channel blockers in preventing and/or overcoming the development of oxaliplatin-induced neurotoxicity.