Phase III evaluation of nortriptyline for alleviation of symptoms of cis-platinum-induced peripheral neuropathy

Efficacy of gabapentin in the management of chemotherapy-induced peripheral neuropathy: a phase 3 randomized, double-blind, placebo-controlled, crossover trial (N00C3)

BACKGROUND

The antiepileptic agent, gabapentin, has been demonstrated to relieve symptoms of peripheral neuropathy due to various etiologies. On the basis of these data, a multicenter, double-blind, placebo-controlled, crossover, randomized trial was conducted to evaluate the effect of gabapentin on symptoms of chemotherapy-induced peripheral neuropathy (CIPN).

METHODS

Patients with symptomatic CIPN who complained of 'average' daily pain scores of either 1) >/=4 on a 0-10 numerical rating scale (NRS); or 2) >/=1 on the 0-3 Eastern Cooperative Oncology Group neuropathy scale (ENS) were eligible (higher numbers indicate greater severity of symptoms in both scales). Patients were randomized to receive gabapentin (target dose, 2700 mg) or placebo for 6 weeks. Crossover occurred after a 2-week washout period. CIPN-related symptoms were evaluated weekly by questionnaires. Statistical methods followed established methods for crossover designs, including Student t tests to compare average intrapatient differences between treatments and linear models to adjust for potential concomitant covariates.

RESULTS

There were 115 patients who were randomly assigned to the treatment or control arm. Both groups were well matched by symptoms at study entry. Changes in symptom severity were statistically similar between the 2 groups during the study. Adverse events were mild and similar in both groups.

CONCLUSIONS

This trial failed to demonstrate any benefit to using gabapentin to treat symptoms caused by CIPN.

Chemotherapy-induced neuropathy

Peripheral neuropathy is a common dose-limiting toxicity of chemotherapy. Chemotherapy-induced peripheral neuropathy (CIPN) causes numerous debilitating symptoms, impairs functional capacity, and results in dose reductions or possible cessation of chemotherapy. Analgesic or neurotropic agents are only modestly effective in treating neuropathic symptoms. Animal and human studies into the pathogenesis of CIPN have demonstrated heterogeneity in the mechanism(s) of nerve injury caused by individual agents, which may partly explain the wide variation in the resultant symptoms. Development of optimal therapeutic measures to treat CIPN requires continued research into the pathophysiologic basis of nerve injury, identification of risk factors for individual patients, development of reproducible and easy-to-use measurement scales, and finally, the performance of appropriately designed clinical trials to evaluate potentially promising agents.

Pharmacologic management of neuropathic pain: evidence-based recommendations

Patients with neuropathic pain (NP) are challenging to manage and evidence-based clinical recommendations for pharmacologic management are needed. Systematic literature reviews, randomized clinical trials, and existing guidelines were evaluated at a consensus meeting. Medications were considered for recommendation if their efficacy was supported by at least one methodologically-sound, randomized clinical trial (RCT) demonstrating superiority to placebo or a relevant comparison treatment. Recommendations were based on the amount and consistency of evidence, degree of efficacy, safety, and clinical experience of the authors. Available RCTs typically evaluated chronic NP of moderate to severe intensity. Recommended first-line treatments include certain antidepressants (i.e., tricyclic antidepressants and dual reuptake inhibitors of both serotonin and norepinephrine), calcium channel alpha2-delta ligands (i.e., gabapentin and pregabalin), and topical lidocaine. Opioid analgesics and tramadol are recommended as generally second-line treatments that can be considered for first-line use in select clinical circumstances. Other medications that would generally be used as third-line treatments but that could also be used as second-line treatments in some circumstances include certain antiepileptic and antidepressant medications, mexiletine, N-methyl-D-aspartate receptor antagonists, and topical capsaicin. Medication selection should be individualized, considering side effects, potential beneficial or deleterious effects on comorbidities, and whether prompt onset of pain relief is necessary. To date, no medications have demonstrated efficacy in lumbosacral radiculopathy, which is probably the most common type of NP. Long-term studies, head-to-head comparisons between medications, studies involving combinations of medications, and RCTs examining treatment of central NP are lacking and should be a priority for future research.

EFNS guidelines on pharmacological treatment of neuropathic pain

Neuropathic pain treatment remains unsatisfactory despite a substantial increase in the number of trials. This EFNS Task Force aimed at evaluating the existing evidence about the pharmacological treatment of neuropathic pain. Studies were identified using first the Cochrane Database then Medline. Trials were classified according to the aetiological condition. All class I and II controlled trials (according to EFNS classification of evidence) were assessed, but lower-class studies were considered in conditions that had no top level studies. Only treatments feasible in an outpatient setting were evaluated. Effects on pain symptoms/signs, quality of life and comorbidities were particularly searched for. Most of the randomized controlled trials included patients with postherpetic neuralgia (PHN) and painful polyneuropathies (PPN) mainly caused by diabetes. These trials provide level A evidence for the efficacy of tricyclic antidepressants, gabapentin, pregabalin and opioids, with a large number of class I trials, followed by topical lidocaine (in PHN) and the newer antidepressants venlafaxine and duloxetine (in PPN). A small number of controlled trials were performed in central pain, trigeminal neuralgia, other peripheral neuropathic pain states and multiple-aetiology neuropathic pains. The main peripheral pain conditions respond similarly well to tricyclic antidepressants, gabapentin, and pregabalin, but some conditions, such as HIV-associated polyneuropathy, are more refractory. There are too few studies on central pain, combination therapy, and head-to-head comparison. For future trials, we recommend to assess quality of life and pain symptoms or signs with standardized tools.

Randomized trial results of quality of life comparing whole abdominal irradiation and combination chemotherapy in advanced endometrial carcinoma: A gynecologic oncology group study

OBJECTIVE

To prospectively compare quality of life (QOL) outcomes in patients with advanced endometrial cancer treated with whole abdominal irradiation (WAI) or doxorubicin-cisplatin (AP) chemotherapy.

METHODS

Using the Fatigue Scale (FS), Assessment of Peripheral Neuropathy (APN), Functional Alterations due to Changes in Elimination (FACE), and Functional Assessment of Cancer Therapy-General (FACT-G), QOL was measured at: pre-treatment, end of treatment (EOT), and 3 and 6 months post-treatment.

RESULTS

317 of 396 eligible patients provided a baseline QOL assessment. The AP arm produced a statistically significant survival benefit along with greater toxicities, including peripheral neuropathy persisting up to 6 months. WAI patients reported worse FS (p < 0.001) and FACE (p < 0.001) scores at EOT and poorer FACE scores 3 months post-treatment (p = 0.004) compared to AP patients. APN scores were significantly worse among AP patients at EOT, and 3 and 6 months post-treatment (p < 0.001 for all). There is no indication that FACT-G scores differed between the two arms at any assessment point.

CONCLUSIONS

The trade-off for increased survival with AP is its potential for clinically significant peripheral neuropathy. This should be discussed with patients, particularly those who work with their hands or on their feet, in weighing therapeutic choices. Further research is needed to manage side effects having an enduring impact on QOL.

The pharmacotherapy of chronic pain: a review

The past two decades have contributed a large body of preclinical work that has assisted in our understanding of the underlying pathophysiological mechanisms that cause chronic pain. In this context, it has been recognized that effective treatment of pain is a priority and that treatment often involves the use of one or a combination of agents with analgesic action. The current review presents an evidence-based approach to the pharmacotherapy of chronic pain. Medline searches were done for all agents used as conventional treatment in chronic pain. Published papers up to June 2005 were included. The search strategy included randomized, controlled trials, and where available, systematic reviews and meta-analyses. Further references were found in reference sections of papers located using the above search strategy. Agents for which there were no controlled trials supporting efficacy in treatment of chronic pain were not included in the present review, except in cases where preclinical science was compelling, or where initial human work has been positive and where it was thought the reader would be interested in the scientific evidence to date.

Peripheral neuropathy: A persisting challenge in paclitaxel-based regimes

Cumulative peripheral neuropathy (PNP) still remains a limitation to optimal treatment with paclitaxel (PAC), especially in more dose-dense schedules. This primary sensory PNP may affect the majority of patients after administration of certain cumulative dosages of PAC, while the exact mechanisms of PAC-induced PNP are not known. While a number of preclinical models revealed its vehicle Cremophor EL (CrEL) to be mainly responsible for ganglionopathy, axonopathy and demyelination, clinical data also supports a strong and independent effect of PAC itself, which is most likely based on disturbances in the microtubules in perikaryons, axons and glia cells. Indeed, clinical trials of CrEL-free formulations of PAC still report grade III neurotoxicity as dose-limiting. As treatment options of PAC-induced PNP are rare the use of specific scoring systems for screening purposes is strongly encouraged. In this report we review and discuss the pathogenesis, incidence, risk factors, diagnosis, pharmacodynamics and treatment options for PAC-induced PNP.

Antidepressants and their effect on sleep

Given the relationship between sleep and depression, there is inevitably going to be an effect of antidepressants on sleep. Current evidence suggests that this effect depends on the class of antidepressant used and the dosage. The extent of variation between the effects of antidepressants and sleep may relate to their mechanism of action. This systematic review examines randomised-controlled trials (RCTs) that have reported the effect that antidepressants appear to have on sleep. RCTs are not restricted to depressed populations, since several studies provide useful information about the effects on sleep in other groups. Nevertheless, the distinction is made between those studies because the participant's health may influence the baseline sleep profiles and the effect of the antidepressant. Insomnia is often seen with monoamine oxidase inhibitors (MAOIs), with all tricyclic antidepressants (TCAs) except amitriptyline, and all selective serotonin reuptake inhibitors (SSRIs) with venlafaxine and moclobemide as well. Sedation has been reported with all TCAs except desipramine, with mirtazapine and nefazodone, the TCA-related maprotiline, trazodone and mianserin, and with all MAOIs. REM sleep suppression has been observed with all TCAs except trimipramine, but especially clomipramine, with all MAOIs and SSRIs and with venlafaxine, trazodone and bupropion. However, the effect on sleep varies between compounds within antidepressant classes, differences relating to the amount of sedative or alerting (insomnia) effects, changes to baseline sleep parameters, differences relating to REM sleep, and the degree of sleep-related side effects.

Cancer pain assessment in clinical trials. A review of the literature (1999-2002)

The aim of this review was to evaluate the methods of pain measurement in controlled clinical trials in oncology published between 1999 and 2002. An electronic literature search strategy was used according to established criteria applied to the Medline database and PubMed search engine. Articles were selected to include only studies that had chronic cancer pain as the primary or secondary objective of a controlled clinical trial. A specific evaluation scheme was used to examine how pain measurement methods were chosen and implemented in the study procedures. The search strategy identified 613 articles, and 68 were selected for evaluation. Most articles (69%) chose unidimensional pain measurement tools, such as visual analogue scales, numerical rating scales and verbal rating scales, whereas others used questionnaires. The implementation of the pain assessment method was problematic in many studies, especially as far as time frame of pain assessment (70%), administration modalities (46%), and use of non-validated measurement methods (10%). Design of study and data analysis were often unclear about the definition of pain outcome measure (40%), patient compliance with pain assessment (98%), and impact of missing data (56%). Statistical techniques were seldom appropriate to the type of data collected and often inadequate to describe the pain variable under study. It is clear from this review that most authors were aware of the need of valid pain measurement tools to be used in clinical trials. However, too often these tools were not appropriately used in the trial, or at least their use was not described with sufficient accuracy in the trial methods.

Seven items were identified for inclusion when reporting a Bayesian analysis of a clinical study

OBJECTIVE

(1) To generate a list of items that experts consider most important when reporting a Bayesian analysis of a clinical study, (2) to report on the extent to which we found these items in the literature, and (3) to identify factors related to the number of items in a report.

STUDY DESIGN AND SETTING

Based on opinions from 23 international experts, we determined the items considered most important when publishing a Bayesian analysis. We then performed a literature search to identify articles in which a Bayesian analysis was performed and determined the extent to which we found these items in each report. Finally, we examined the relationship between the number of items in a report and journal- and article-specific attributes.

RESULTS

Our final set of seven items described the prior distribution (specification, justification, and sensitivity analysis), analysis (statistical model and analytic technique), and presentation of results (central tendency and variance). There was >99% probability that more items were reported in studies with a noncontrolled study design and in journals with a methodological focus, lower impact factor, and absence of a word count limit.

CONCLUSION

We developed a set of seven items that experts believe to be most important when reporting a Bayesian analysis.

Attenuation of mechanical allodynia by clinically utilized drugs in a rat chemotherapy-induced neuropathic pain model

Chemotherapy-induced peripheral neuropathy is a common, dose-limiting side effect of cancer chemotherapeutic agents, including the vinca alkaloids such as vincristine. The resulting symptoms, which frequently include moderate to severe pain, can often be disabling. The current study utilized a vincristine-induced neuropathic pain animal model [Pain 93 (2001) 69], in which rats were surgically implanted with mini-osmotic pumps set to deliver vincristine sulfate (30 microg kg(-1)day(-1), i.v.), to examine the time course of progression of various pain modalities and to compare the dose-response effects of clinically utilized drugs on mechanical allodynia to further validate the relevance of this model to clinical pathology. Vincristine infusion resulted in significant cold allodynia after 1 week post-infusion, however mechanical and thermal nociception showed little to no effect. In contrast, marked mechanical allodynia occurred by 1 week of vincristine infusion and returned nearly to pre-infusion levels by the 4th week after infusion pump implantation. ED(50) values (micromol/kg, p.o.) were determined in the mechanical allodynia assay for lamotrigine (82), dextromethorphan (94), gabapentin (400), acetaminophen (1100) and carbamazepine (3600); however, aspirin and ibuprofen had no effects up to 300 and 1000 micromol/kg, respectively. Additionally, ED(50) values (micromol/kg, i.p.) were determined in the mechanical allodynia assay for clonidine (0.35) and morphine (0.62), but desipramine and celecoxib had no effects up to 66 and 260 micromol/kg, respectively. Findings from the current, preclinical study further validate this model as clinically relevant for chemotherapy-induced pain. The surprisingly good effects observed with acetaminophen warrant further investigation of its mechanism(s) of action in neuropathic pain.