Τρίτη 5 Νοεμβρίου 2019

An Update on Vitamin D and Disease Activity in Multiple Sclerosis

Abstract

Vitamin D and its main active metabolite 1,25-dihydroxyvitamin D serve a crucial role in maintenance of a healthy calcium metabolism, yet have additional roles in immune and central nervous system cell homeostasis. Serum levels of 25-hydroxyvitamin D are a biomarker of future disease activity in patients with early relapsing–remitting multiple sclerosis (RRMS), and vitamin D supplementation in patients with low circulating 25-dihydroxyvitamin D levels has been anticipated as a potential efficacious treatment strategy. The results of the first large randomized clinical trials (RCTs), the SOLAR and CHOLINE studies, have now been published. The SOLAR study compared 14,000 IU of vitamin D3 (cholecalciferol) per day with placebo for 48 weeks in 232 randomized patients, whereas CHOLINE compared vitamin D3 100,000 IU every other week with placebo for 96 weeks in 129 randomized patients. All patients in both studies also used interferon-β-1a. None of the studies met their primary endpoints, which were no evidence of disease activity (NEDA-3) at 48 weeks in SOLAR and annualized relapse rate at 96 weeks in CHOLINE. Both studies did, however, suggest modest effects on secondary endpoints. Thus, vitamin D reduced the number of new or enlarging lesions and new T2 lesions in SOLAR, and the annualized relapse rate and number of new T1 lesions, volume of hypointense T1 lesions, and disability progression in the 90 patients who completed 96 weeks’ follow-up in CHOLINE. We conclude that none of the RCTs on vitamin supplementation in MS have met their primary clinical endpoint in the intention to treat cohorts. This contrasts the observation studies, where each 25 nmol/l increase in 25-hydroxyvitamin D levels were associated with 14–34% reduced relapse risk and 15–50% reduced risk of new lesions on magnetic resonnance imaging. This discrepancy may have several explanations, including confounding and reverse causality in the observational studies. The power calculations of the RCTs have been based on the observational studies, and the RCTs may have been underpowered to detect less prominent yet important effects of vitamin D supplementation. Although the effect of vitamin D supplementation is uncertain and less pronounced than suggested by observational studies, current evidence still support that people with MS should avoid vitamin D insufficiency, and preferentially aim for vitamin D levels around 100 nmol/L or somewhat higher.

Risk Factors Associated with the Occurrence of Neonatal Opioid Withdrawal Syndrome: A Review

Abstract

In a number of countries, the prevalence of neonatal opioid withdrawal syndrome (NOWS) is increasing. While NOWS is ultimately the result of opioid exposure in utero, a wide range of risk factors have been associated with the prevalence of NOWS, extending beyond just drug exposure. This article reviews the available literature on factors associated with the incidence of NOWS in opioid-exposed neonates. A range of risk factors have been associated with NOWS, including features of neonatal drug exposure, maternal and neonatal characteristics, aspects of labor and delivery, and genetics. Increased length of gestation and higher birth weight were consistently associated with an increased risk of NOWS, while breast feeding and ‘rooming-in’ were associated with a reduced risk of NOWS. Additionally, several genetic factors have also been associated with NOWS severity. There is conflicting evidence on the association between NOWS and other risk factors including opioid dose, neonate sex, and the use of some medications during pregnancy. This may be in part attributable to differences in how NOWS is diagnosed and the variety of methodologies across studies. While a large number of risk factors associated with NOWS are non-modifiable, encouraging pregnant women to reduce other drug use (including smoking), breast feed their child, and the judicious use of medications during pregnancy may help reduce the prevalence of NOWS. The presence or absence of NOWS in an opioid-exposed neonate is associated with a wide range of factors. Some of these modifiable risk factors may be potential targets for the primary prevention of NOWS.

Ischemic and Thrombotic Events Associated with Concomitant Xa-inhibiting Direct Oral Anticoagulants and Antiepileptic Drugs: Analysis of the FDA Adverse Event Reporting System (FAERS)

Abstract

Introduction

Factor Xa-inhibiting direct oral anticoagulants (FXa-DOACs) undergo hepatic metabolism via cytochrome P-450 (CYP450). Concomitant use of rifampicin, an inducer of these enzymes, with FXa-DOACs, has been shown to decrease FXa-DOAC concentrations in healthy subjects. Several common antiepileptic drugs (AEDs) are known to induce CYP450 enzymes as well. However, little is known regarding the impact of this potential interaction on treatment outcomes with FXa-DOACs.

Methods

We analyzed adverse event cases submitted to the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) from January 2013 to December 2018. We compared the proportion of cases reporting thromboembolic and ischemic adverse events (TAIAEs) with the concomitant use of FXa-DOACs and enzyme-inducing AEDs to the proportion of cases with FXa-DOACs and other AEDs.

Results

During this period, 9693 adverse event cases reported concomitant use of FXa-DOACs and AEDs. Almost all reports (> 99%) involved the use of rivaroxaban or apixaban. Compared with other AEDs, enzyme-inducing AEDs were associated with an 86% increase in the odds of reporting TAIAEs [reporting odds ratio (ROR) 1.86, 95% confidence interval (CI) 1.61–2.15; p < 0.0001]. In secondary separate analyses of rivaroxaban and apixaban, enzyme-inducing AEDs were similarly associated with increased reporting of a TAIAE (ROR 1.79, 95% CI 1.50–2.12, and ROR 1.88, 95% CI 1.41–2.48, respectively).

Conclusion

Using real world data, we observed an increase in the odds of reporting anticoagulation treatment failure among patients treated with FXa-DOACs and concomitant enzyme-inducing AEDs compared to those treated with other AEDs.

Relative Seizure Relapse Risks Associated with Antiepileptic Drug Withdrawal After Different Seizure-Free Periods in Adults with Focal Epilepsy: A Prospective, Controlled Follow-Up Study

Abstract

Background

Approximately two-thirds of patients with newly diagnosed epilepsy become seizure-free after antiepileptic drug (AED) treatment. A crucial issue for these patients and their families, especially after a long period of seizure freedom, is when to stop their medications.

Objective

The aim of this study was to identify the optimal timing of AED withdrawal in adults with focal epilepsy who had been seizure-free for ≥ 2 years.

Methods

Adults with focal epilepsy who had been seizure-free for ≥ 2 years were recruited. Based on their decision to discontinue (withdrawal) or continue (non-withdrawal) AED treatment, patients were assigned to withdrawal or non-withdrawal subgroups according to the length of remission (2 to < 3 years, 3 to < 4 years, 4 to < 5 years and ≥ 5 years). The relapse risks of the withdrawal and corresponding non-withdrawal subgroups were compared, and the relative relapse risks were assessed in a Cox proportional hazard regression model.

Results

A total of 213 eligible patients began to withdraw from AED treatment; 70 had been seizure-free for 2 to < 3 years, 62 had been seizure-free for 3 to < 4 years, 37 had been seizure-free for 4 to < 5 years and 44 had been seizure-free for ≥ 5 years. The figures for the corresponding non-withdrawal subgroups were 463, 334, 251 and 182, respectively. There was a significantly higher risk of seizure relapse in patients withdrawing from AEDs after 2 to < 5 years of seizure freedom than in the corresponding non-withdrawal controls, and the relative relapse risk was 3.052 (95% confidence interval [CI] 2.126–4.381; p < 0.001) for the seizure-free period of 2 to < 3 years, 3.617 (95% CI 2.384–5.488; p < 0.001) for 3 to < 4 years and 2.644 (95% CI 1.456–4.799; p = 0.001) for 4 to < 5 years. However, for patients who were seizure-free for ≥ 5 years, AED withdrawal did not significantly increase the risk of seizure relapse compared with that of patients continuing treatment (hazard ratio [HR] 1.362, 95% CI 0.634–2.926, p = 0.428). Compared with a seizure-free period of 2 to < 3 years, the relative relapse risk after AED withdrawal was significantly reduced only after being seizure-free for ≥ 5 years (HR 0.441, 95% CI 0.233–0.834; p = 0.012).

Conclusion

Overall, for adults with focal epilepsy, withdrawal from AEDs significantly increased the risk of seizure relapse after being seizure-free for 2 to < 5 years, but might not increase the risk if the seizure-free period was ≥ 5 years.

The Potential Therapeutic Capacity of Inhibiting the Brain Renin–Angiotensin System in the Treatment of Co-Morbid Conditions in Epilepsy

Abstract

Epilepsy is one of the most prevalent neurological diseases and although numerous novel anticonvulsants have been approved, the proportion of patients who are refractory to medical treatment of seizures and have progressive co-morbidities such as cognitive impairment and depression remains at about 20–30%. In the last decade, extensive research has identified a therapeutic capacity of the components of the brain renin–angiotensin system (RAS) in seizure- and epilepsy-related phenomena. Alleviating the activity of RAS in the central nervous system is considered to be a potential adjuvant strategy for the treatment of numerous detrimental consequences of epileptogenesis. One of the main advantages of RAS is associated with its modulatory influence on different neurotransmitter systems, thereby exerting a fine-tuning control mechanism for brain excitability. The most recent scientific findings regarding the involvement of the components of brain RAS show that angiotensin II (Ang II), angiotensin-converting enzyme (ACE), Ang II type 1 (AT1) and type 2 (AT2) receptors are involved in the control of epilepsy and its accompanying complications, and therefore they are currently of therapeutic interest in the treatment of this disease. However, data on the role of different components of brain RAS on co-morbid conditions in epilepsy, including hypertension, are insufficient. Experimental and clinical findings related to the involvement of Ang II, ACE, AT1, and AT2 receptors in the control of epilepsy and accompanying complications may point to new therapeutic opportunities and adjuvants for the treatment of common co-morbid conditions of epilepsy.

Treatment with Dimethyl Fumarate Enhances Cholinergic Transmission in Multiple Sclerosis

Abstract

Background

Dimethyl fumarate (DMF) exerts anti-inflammatory effects in multiple sclerosis by activating the Nrf2 antioxidant pathway, which is also stimulated by acetylcholine via alpha-7 nicotinic acetylcholine receptors. In animal models, Nrf2 potentiates cholinergic synaptic plasticity.

Objective

The aim of this study was to test whether treatment with DMF modulates cholinergic pathways in relapsing-remitting multiple sclerosis (RRMS).

Methods

Patients starting DMF (20) or IFN-β 1a (20) and healthy subjects (20) were enrolled. Short-latency afferent inhibition (SAI), which is a transcranial stimulation measure of central cholinergic transmission, was recorded in patients and controls at baseline and, in patients only, after 6 months of treatment. Patients treated with DMF also underwent autonomic function testing to further explore peripheral and central cholinergic tone.

Results

At baseline, SAI was similar in patients and in controls (p = 0.983). Treatment with DMF significantly increased SAI (p = 0.01), while IFNβ had no effect (p = 0.80). In the cold face test, DMF treatment also increased reflex bradycardia (p = 0.013), and reduced diastolic blood pressure variation (p = 0.010), further indicating its ability to stimulate cholinergic transmission.

Conclusions

Treatment of MS patients with DMF results in increased cholinergic stimulation, with possible implications for neuroinflammation and neuroprotection.

Effects of Fampridine in People with Multiple Sclerosis: A Systematic Review and Meta-analysis

Abstract

Background

Prolonged-release (PR) fampridine is a potassium channel blocker used as a symptomatic treatment for walking disability in patients with multiple sclerosis (MS). Its clinical effects in such patients have not been systematically reviewed, and may be more wide-ranging than expected.

Objectives

To summarize the evidence on the effects of PR fampridine in patients with MS.

Methods

A systematic search of Pubmed, Scopus (including EMBASE), and PsycINFO (completed in 01/2019) was carried out to identify randomized controlled trials (RCT) that compared PR fampridine to placebo. When appropriate, data were pooled using a random-effects model, and standardized mean differences (SMD) were computed. Study quality was assessed using the Downs and Black checklist. PRISMA guidelines were followed. All retrieved functional outcomes were categorized according to the International Classification of Functioning, Disability and Health (ICF).

Results

A total of 706 articles were screened for inclusion. Twenty RCTs involving 2616 patients met the eligibility criteria. Most studies were of good-to-excellent quality. PR fampridine administration resulted in significant benefits in relation to walking short distances (SMD: 1.23 (95% IC 0.65–1.81)) and perceived walking capacity (0.64 (0.27–1.02)). Its effects on muscle strength and middle-distance walking were not significant (0.53 (− 0.04 to 1.10) and 0.31 (− 0.18 to 0.80), respectively). No effect on higher-level cognitive functions (− 0.07 (− 0.58 to 0.45)) or hand and arm use (0.16 (− 0.33 to 0.64)) was observed. Individual studies reported effects on other outcomes across the ICF domains.

Conclusions

There is strong evidence that PR fampridine exerts strong effects on the ability to walk short distances and on perceived walking capacity. Other effects of PR fampridine according to the ICF are possible but still unclear.

Meta-Analysis of Placebo Response in Adult Antidepressant Trials

Abstract

Background

Roughly 80% of the symptom improvement experienced on antidepressants in clinical trials is also observed in the placebo comparison group. Understanding the correlates of placebo improvement and response is important to designing efficient and successful trials of future antidepressants.

Objective

The objective of this meta-analysis was to investigate the magnitude of placebo symptom improvement and placebo response rates in second-generation antidepressant trials of depression, anxiety, and obsessive-compulsive disorder.

Methods

We searched PubMed on 10 June, 2016, with no date or language limits, to identify randomized placebo-controlled trials of second-generation antidepressants in adults with depression, anxiety, or obsessive-compulsive disorder. We used a random-effects meta-analysis to examine the magnitude of placebo symptom improvement using standardized mean difference and placebo response rate. Stratified subgroup analysis and meta-regression were utilized to examine the effect of diagnostic indication and correlates of placebo symptom improvement.

Results

The meta-analysis included 164 trials involving 19,591 participants. Magnitude of placebo improvement and placebo response rates varied significantly between diagnostic indications. The magnitude of placebo improvement was much lower in obsessive-compulsive disorder (standardized mean difference = 0.58, 95% confidence interval 0.36–0.79) than in depression (standardized mean difference = 1.22, 95% confidence interval 1.12–1.32) or anxiety (standardized mean difference = 1.01, 95% confidence interval 0.90–1.12) trials. There was a large amount of heterogeneity in placebo improvement between studies (Q = 899, df = 110, p < 0.001, I2 = 88%). A greater number of study sites and a later publication year were associated with a greater magnitude of placebo improvement and response rate. Presence of a placebo lead-in and absence of non-US sites were associated with a reduced magnitude of placebo improvement. Trial duration was positively associated with the magnitude of placebo improvement in depression trials but negatively associated with the magnitude of placebo improvement in anxiety and obsessive-compulsive disorder trials.

Conclusions

Magnitude of placebo symptom improvement differed significantly based on diagnostic indication with improvement being significantly less in obsessive-compulsive disorder than anxiety and depression. Some trial characteristics were associated with a greater magnitude of placebo improvement in trials across disorders but others were disorder specific.

Opioid-Induced Tolerance and Hyperalgesia

Abstract

Opioids are very potent and efficacious drugs, traditionally used for both acute and chronic pain conditions. However, the use of opioids is frequently associated with the occurrence of adverse effects or clinical problems. Other than adverse effects and dependence, the development of tolerance is a significant problem, as it requires increased opioid drug doses to achieve the same effect. Mechanisms of opioid tolerance include drug-induced adaptations or allostatic changes at the cellular, circuitry, and system levels. Dose escalation in long-term opioid therapy might cause opioid-induced hyperalgesia (OIH), which is a state of hypersensitivity to painful stimuli associated with opioid therapy, resulting in exacerbation of pain sensation rather than relief of pain. Various strategies may provide extra-opioid analgesia. There are drugs that may produce independent analgesic effects. A tailored treatment provided by skilled personnel, in accordance with the individual condition, is mandatory. Any treatment aimed at reducing opioid consumption may be indicated in these circumstances. Interventional techniques able to decrease the pain input may allow a decrease in the opioid dose, thus reverting the mechanisms producing tolerance of OIH. Intrathecal therapy with local anesthetics and a sympathetic block are the most common techniques utilized in these circumstances.

Using Matching-Adjusted Indirect Comparisons and Network Meta-analyses to Compare Efficacy of Brexanolone Injection with Selective Serotonin Reuptake Inhibitors for Treating Postpartum Depression

Abstract

Background

Brexanolone injection, the first therapy approved by the US FDA for the treatment of postpartum depression (PPD) in adults, has been shown to produce a significantly greater decrease in the Hamilton Rating Scale for Depression (HAM-D) total score than placebo in randomised controlled trials (RCTs) of women with PPD.

Objectives

Given the rapid effect of brexanolone injection (within 60 h) sustained throughout the length of the trials (30 days), we sought to compare its efficacy data against selective serotonin reuptake inhibitors (SSRIs), the class of antidepressants most commonly prescribed for PPD, using HAM-D and Edinburgh Postnatal Depression Scale (EPDS) outcomes from currently available RCTs.

Methods

We extracted data from 26 studies identified in a systematic literature review of pharmacological and pharmacological/nonpharmacological combination therapies in PPD. Six studies were suitable to form evidence networks through which to perform indirect treatment comparisons (ITCs) of HAM-D and EPDS outcomes between brexanolone and SSRIs. Having assessed the comparability and suitability of the available evidence for analysis, we discovered significant heterogeneity in the study designs, most notably in the placebo arms of the trials. We therefore conducted matching-adjusted indirect comparisons (MAICs) between brexanolone and the placebo arms of comparator studies, subsequently using the MAIC results of brexanolone versus placebo, and results for SSRIs versus placebo, to form ITCs of brexanolone versus SSRIs at three separate time points—day 3, week 4 and last observation. ITCs were calculated as the differences in change from baseline (CFB) in HAM-D and, separately, CFB in EPDS, between treatments, and reported with 95% confidence intervals (CIs).

Results

For all time points, MAICs showed larger differences in CFB for brexanolone compared with SSRIs. Differences (95% CIs) between brexanolone and SSRIs were 12.79 (8.04–17.53) [day 3], 5.87 (− 1.62 to 13.37) [week 4] and 0.97 (− 6.35 to 8.30) [last observation] for the HAM-D. For the EPDS, the differences in CFB were 7.98 (5.32–10.64) [day 3], 6.35 (3.13–9.57) [week 4] and 4.05 (0.79–7.31) [last observation]. Other analytical approaches are also presented to demonstrate the similarity of results, using a network meta-analysis approach, and the importance of using the MAIC method to control for the important heterogeneity between placebo arms.

Conclusions

Acknowledging the limitations of ITCs and this evidence base, when compared with SSRIs, these analyses suggest that brexanolone demonstrated larger differences in CFB for both patient- and clinician-reported PPD outcomes and at all investigated time points after adjusting for differences between placebos in the included studies.

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