New players in the preventive treatment of migraine

Numbers needed to treat or harm and likelihood of being helped versus harmed for fremanezumab in patients who had prior inadequate response to two to four classes of migraine preventive medications: A post hoc analysis

OBJECTIVE

This study aimed to determine the number needed to treat (NNT), number needed to harm (NNH), and likelihood of being helped or harmed (LHH) in a post hoc analysis of the phase 3b FOCUS trial.

BACKGROUND

Fremanezumab, a humanized monoclonal antibody that selectively targets calcitonin gene-related peptide (CGRP), has demonstrated efficacy, tolerability, and safety in adults with episodic migraine (EM) or chronic migraine (CM), with documented previous inadequate response to two to four classes of migraine preventive medications.

METHODS

In the 12-week double-blind period of the FOCUS study, patients were randomized (1:1:1) to quarterly fremanezumab, monthly fremanezumab, or matched monthly placebo. NNT was based on responder analysis, defined as ≥50% reduction in monthly average number of migraine days at 12 weeks. NNH was based on discontinuations due to adverse events (AEs).

RESULTS

Among patients with CM (n = 509), response rates and discontinuation rates were 27% (45/169) and 0 for quarterly fremanezumab, 29% (50/173) and 2% (3/173) for monthly fremanezumab, and 8% (13/167) and <1% (1/167) for placebo, respectively. These results translated to NNTs of 5.3 and 4.7, NNHs of 1000 and 88, and LHHs of 188 and 19 for quarterly and monthly fremanezumab, respectively. Among patients with EM (n = 328), response rates were 47% (50/107) for quarterly fremanezumab, 43% (47/110) for monthly fremanezumab, and 10% (11/111) for placebo. Discontinuation rates were <1% (n = 1) in all three groups. These results translated to NNTs of 2.7 and 3.0, NNHs of 1000 and 1000, and LHHs of 368 and 328 for quarterly and monthly fremanezumab, respectively.

CONCLUSIONS

The NNT, NNH, and LHH for quarterly and monthly fremanezumab compare favorably with those for traditional oral preventive medications, including topiramate, valproate, and propranolol.

Calcitonin Gene-Related Peptide and Adrenomedullin Levels During Ictal and Interictal Periods in Patients With Migraine

Background Peptides related to calcitonin gene-related peptide (CGRP) have been suggested to have a role in migraine. Adrenomedullin (AM) might be a candidate molecule because it is related to pain pathways in the peripheral and central nervous systems and uses the same receptors as CGRP. Methodology In this study, we examined the serum CGRP and AM levels during unprovoked ictal and interictal periods of 30 migraine patients as well as 25 healthy controls. Another focus of this study was on the association of CGRP and AM levels with clinical features. Results Mean serum AM levels were 15.80 pg/mL (11.91-21.43 pg/mL) in the ictal and 15.85 pg/mL (12.25-19.29 pg/mL) in the interictal periods in the migraine group and 13.36 pg/mL (10.84-17.18 pg/mL) in the control group. Mean serum CGRP levels were 2.93 pg/mL (2.45-3.90 pg/mL) in the ictal and 3.25 pg/mL (2.85-4.67 pg/mL) in the interictal periods in the migraine group and 3.03 pg/mL (2.48-3.80 pg/mL) in the control group. There were no statistical differences between ictal and/or interictal AM and CGRP levels (p = 0.558 and p = 0.054, respectively) which were also comparable with the results of the control group (p = 0.230, p = 0.295, p = 0.987, p = 0.139, respectively). Ictal serum CGRP and/or AM levels did not correlate with any of the reported clinical features. Conclusions Serum AM and CGRP levels are similar in interictal and unprovoked ictal periods in migraine patients and as well in controls. These results do not indicate that these molecules do not have a role in migraine pathophysiology. Considering the broad mechanisms of action of peptides in the CGRP family, further studies are needed in larger cohorts.

Vitamin D in Neurological Diseases

Vitamin D may have multiple effects on the nervous system and its deficiency can represent a possible risk factor for the development of many neurological diseases. Recent studies are also trying to clarify the different effects of vitamin D supplementation over the course of progressive neurological diseases. In this narrative review, we summarise vitamin D chemistry, metabolism, mechanisms of action, and the recommended daily intake. The role of vitamin D on gene transcription and the immune response is also reviewed. Finally, we discuss the scientific evidence that links low 25-hydroxyvitamin D concentrations to the onset and progression of severe neurological diseases, such as multiple sclerosis, Parkinson's disease, Alzheimer's disease, migraine, diabetic neuropathy and amyotrophic lateral sclerosis. Completed and ongoing clinical trials on vitamin D supplementation in neurological diseases are listed.

Gel-forming antagonist provides a lasting effect on CGRP-induced vasodilation

Migraine affects ∼15% of the adult population, and the standard treatment includes the use of triptans, ergotamines, and analgesics. Recently, CGRP and its receptor, the CLR/RAMP1 receptor complex, have been targeted for migraine treatment due to their critical roles in mediating migraine headaches. The effort has led to the approval of several anti-CGRP antibodies for chronic migraine treatment. However, many patients still suffer continuous struggles with migraine, perhaps due to the limited ability of anti-CGRP therapeutics to fully reduce CGRP levels or reach target cells. An alternative anti-CGRP strategy may help address the medical need of patients who do not respond to existing therapeutics. By serendipity, we have recently found that several chimeric adrenomedullin/adrenomedullin 2 peptides are potent CLR/RAMP receptor antagonists and self-assemble to form liquid gels. Among these analogs, the ADE651 analog, which potently inhibits CLR/RAMP1 receptor signaling, forms gels at a 6-20% level. Screening of ADE651 variants indicated that residues at the junctional region of this chimeric peptide are important for gaining the gel-forming capability. Gel-formation significantly slowed the passage of ADE651 molecules through Centricon filters. Consistently, subcutaneous injection of ADE651 gel in rats led to the sustained presence of ADE651 in circulation for >1 week. In addition, analysis of vascular blood flow in rat hindlimbs showed ADE651 significantly reduces CGRP-induced vasodilation. Because gel-forming antagonists could have direct and sustained access to target cells, ADE651 and related antagonists for CLR/RAMP receptors may represent promising candidates for targeting CGRP- and/or adrenomedullin-mediated headaches in migraine patients.

The locus of Action of CGRPergic Monoclonal Antibodies Against Migraine: Peripheral Over Central Mechanisms

Migraine is a complex neurovascular disorder characterized by attacks of moderate to severe unilateral headache, accompanied by photophobia among other neurological signs. Although an arsenal of antimigraine agents is currently available in the market, not all patients respond to them. As Calcitonin Gene-Related Peptide (CGRP) plays a key role in the pathophysiology of migraine, CGRP receptor antagonists (gepants) have been developed. Unfortunately, further pharmaceutical development (for olcegepant and telcagepant) was interrupted due to pharmacokinetic issues observed during the Randomized Clinical Trials (RCT). On this basis, the use of monoclonal antibodies (mAbs; immunoglobulins) against CGRP or its receptor has recently emerged as a novel pharmacotherapy to treat migraines. RCT showed that these mAbs are effective against migraines producing fewer adverse events. Presently, the U.S. Food and Drug Administration approved four mAbs, namely: (i) erenumab; (ii) fremanezumab; (iii) galcanezumab; and (iv) eptinezumab. In general, specific antimigraine compounds exert their action in the trigeminovascular system, but the locus of action (peripheral vs. central) of the mAbs remains elusive. Since these mAbs have a molecular weight of ∼150 kDa, some studies rule out the relevance of their central actions as they seem unlikely to cross the Blood-Brain Barrier (BBB). Considering the therapeutic relevance of this new class of antimigraine compounds, the present review has attempted to summarize and discuss the current evidence on the probable sites of action of these mAbs.

Riboflavin in Neurological Diseases: A Narrative Review

Riboflavin is classified as one of the water-soluble B vitamins. It is part of the functional group of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) cofactors and is required for numerous flavoprotein-catalysed reactions. Riboflavin has important antioxidant properties, essential for correct cell functioning. It is required for the conversion of oxidised glutathione to the reduced form and for the mitochondrial respiratory chain as complexes I and II contain flavoprotein reductases and electron transferring flavoproteins. Riboflavin deficiency has been demonstrated to impair the oxidative state of the body, especially in relation to lipid peroxidation status, in both animal and human studies. In the nervous system, riboflavin is essential for the synthesis of myelin and its deficiency can determine the disruption of myelin lamellae. The inherited condition of restricted riboflavin absorption and utilisation, reported in about 10-15% of world population, warrants further investigation in relation to its association with the main neurodegenerative diseases. Several successful trials testing riboflavin for migraine prevention were performed, and this drug is currently classified as a Level B medication for migraine according to the American Academy of Neurology evidence-based rating, with evidence supporting its efficacy. Brown-Vialetto-Van Laere syndrome and Fazio-Londe diseases are now renamed as "riboflavin transporter deficiency" because these are autosomal recessive diseases caused by mutations of SLC52A2 and SLC52A3 genes that encode riboflavin transporters. High doses of riboflavin represent the mainstay of the therapy of these diseases and high doses of riboflavin should be rapidly started as soon as the diagnosis is suspected and continued lifelong. Remarkably, some mitochondrial diseases respond to supplementation with riboflavin. These include multiple acyl-CoA-dehydrogenase deficiency (which is caused by ETFDH gene mutations in the majority of the cases, or mutations in the ETFA and ETFB genes in a minority), mutations of ACAD9 gene, mutations of AIFM1 gene, mutations of the NDUFV1 and NDUFV2 genes. Therapeutic riboflavin administration has been tried in other neurological diseases, including stroke, multiple sclerosis, Friedreich's ataxia and Parkinson's disease. Unfortunately, the design of these clinical trials was not uniform, not allowing to accurately assess the real effects of this molecule on the disease course. In this review we analyse the properties of riboflavin and its possible effects on the pathogenesis of different neurological diseases, and we will review the current indications of this vitamin as a therapeutic intervention in neurology.

Effect of Vitamin B2 supplementation on migraine prophylaxis: a systematic review and meta-analysis

OBJECTIVE

Migraine is a common disease worldwide and migraine prevention is primarily currently based on pharmaceuticals. The mechanism of Vitamin B2 may positively contribute to migraine. This systematic review and meta-analysis aimed to evaluate the impact of Vitamin B2 supplementation on the days, duration, frequency, and pain score of the migraine attack.

METHODS

: The PRISMA guideline was used for the studying process. Five electronic databases, PubMed, Embase, Cochrane, CINAHL, and CEPS were searched from 1990 to March 2019. The search terms were Vitamin B2, migraine, and prophylactic. A meta-analysis was performed using Comprehensive Meta-Analysis (CMA) version.

RESULTS

: Nine articles were included in systemic review and finally meta-analysis. Eight randomized controlled trials and one controlled clinical trial with 673 subjects were analyzed using meta-analysis. Vitamin B2 supplementation significantly decreased migraine days (p = .005, I² = 89%), duration (p = .003, I² = 0), frequency (p = .001, I² = 65%), and pain score (p = .015, I² = 84%).

CONCLUSIONS

A pooled analysis of available randomized controlled clinical trials demonstrated that Vitamin B2 400 mg/day for three months supplementation had significant effect on days, duration, frequency, and pain score of migraine attacks.

Anti-CGRP monoclonal antibodies for migraine prevention: A systematic review and likelihood to help or harm analysis

INTRODUCTION AND OBJECTIVE

Monoclonal antibodies targeting the calcitonin gene-related peptide pathway (anti-CGRP mAbs) have shown promising efficacy in randomised clinical trials for the prevention of episodic and chronic migraine, but no head-to-head comparisons with established treatments are available. We aimed to examine absolute differences in benefit-risk ratios between anti-CGRP mAbs, topiramate and propranolol for the prevention of episodic migraine and between anti-CGRP mAbs, topiramate and onabotulinumtoxinA for the prevention of chronic migraine using a likelihood to help versus harm analysis.

METHODS

The number of patients needed to be treated for a patient to achieve ≥ 50% reduction in migraine days (NNTB_50%) was used as an effect size metric of efficacy. The number of patients needed to be treated for a patient to experience an adverse event that led to treatment discontinuation (NNTH_D-AE) was used as a measure of risk. Likelihood to help versus harm values - which are the ratios of NNTH:NNTB - were calculated using data from phase 3 randomised clinical trials.

RESULTS

All agents tested were more likely to be beneficial than harmful (likelihood to help versus harm > 1) with the exception of topiramate at 200 mg per day for the prevention of episodic migraine. Anti-CGRP mAbs in all tested doses had higher LHH values than propranolol or topiramate for episodic migraine and onabotulinumtoxinA or topiramate for chronic migraine prevention. Fremanezumab had the highest LHH ratio in episodic migraine and galcanezumab in chronic migraine.

CONCLUSION

This analysis showed that anti-CGRP mAbs exhibit a more favourable benefit-risk ratio than established treatments for episodic and chronic migraine. Head-to-head studies are needed to confirm these results.

A population-based survey for disabling headaches in Greece: Prevalence, burden and treatment preferences

OBJECTIVE

To estimate the prevalence, burden and current treatment of disabling primary headaches in a large sample of the Greek population aged 18-70 years old.

METHODS

This is an observational descriptive study, with cross-sectional design performed by quantitative computer-assisted telephone interviews, using a validated 37-item questionnaire for headaches. The prevalence, burden, and current treatment of primary headaches (ICHD-3) were recorded along with participants' treatment preferences.

RESULTS

Out of 10,008 interviewed participants, 1197 (12.0%) reported headaches affecting performance. The annual prevalence of migraine was 8.1% (95% confidence interval, 7.6-8.7, corresponding to 0.6 million Greeks), of chronic migraine 1.0% (95% confidence interval, 0.8-1.2, corresponding to 0.1 million), and of tension-type headache 3.8% (95% confidence interval, 3.4-4.2, corresponding to 0.3 million). The participants with headaches reported 0.5 headache-induced lost workdays per month (corresponding to 5.8 million lost workdays annually) and reductions in performance on 2.8 workdays per month (corresponding to 30.9 million workdays annually). In all, 43.4% of headache participants felt bad/ashamed because of headaches and 21.9% sought professional treatment, most often from a private neurologist. 83.8% of headache participants had never taken pharmacological prophylaxis, and only 5.5% were currently under preventative treatment. For both prophylactic and acute treatment, headache participants prefer oral medication to injection or stimulation devices.

CONCLUSION

More than 10% of the Greek adult population up to 70 years old experience disabling headaches, causing a dramatic work loss. More than 80% of these have never taken pharmacological prophylaxis. Thus, enriching the quality of life of people with headaches relies crucially on expanding awareness about headaches and their treatment.

Monoclonal Antibodies as Neurological Therapeutics

Over the last 30 years the role of monoclonal antibodies in therapeutics has increased enormously, revolutionizing treatment in most medical specialties, including neurology. Monoclonal antibodies are key therapeutic agents for several neurological conditions with diverse pathophysiological mechanisms, including multiple sclerosis, migraines and neuromuscular disease. In addition, a great number of monoclonal antibodies against several targets are being investigated for many more neurological diseases, which reflects our advances in understanding the pathogenesis of these diseases. Untangling the molecular mechanisms of disease allows monoclonal antibodies to block disease pathways accurately and efficiently with exceptional target specificity, minimizing non-specific effects. On the other hand, accumulating experience shows that monoclonal antibodies may carry class-specific and target-associated risks. This article provides an overview of different types of monoclonal antibodies and their characteristics and reviews monoclonal antibodies currently in use or under development for neurological disease.

Three new drugs for the prevention of migraine

DTB drug reviews provide an overview of medicines that have been recently launched in the UK. The articles include a summary of the evidence of benefits and harms as well as details of the regulatory authority's assessment report.

Monoclonal antibodies blocking CGRP transmission: An update on their added value in migraine prevention

The avenue of effective migraine therapies blocking calcitonin gene-related peptide (CGRP) transmission is the successful outcome of 35 years of translational research. Developed after short-acting, the small antagonists of the CGRP receptor (the "gepants"), the monoclonal antibodies blocking CGRP or its receptor (CGRP/rec mAbs) have changed the paradigm in migraine treatment. Contrary to the classical acute medications like triptans or nonsteroidal anti-inflammatory drugs (NSAIDs) with a transient effect, they act for long durations exclusively in the peripheral portion of the trigeminovascular system and can thus be assimilated to a durable attack treatment, unlike the classical preventives that chiefly act upstream on the central facets of migraine pathophysiology. Randomized controlled trials (RCT) of eptinezumab, erenumab, fremanezumab and galcanezumab have included collectively several thousands of patients, making them the most extensively studied class of preventive migraine treatments. Their results clearly indicate that CGRP/rec mAbs are significantly superior to placebo and have been comprehensively reviewed by Dodick [Cephalalgia 2019;39(3):445-458]. In this review we will briefly summarize the placebo-subtracted outcomes and number-needed-to-treat (NNT) of these pivotal RCTs and analyze new and post-hoc studies published afterwards focusing on effect size, effect onset and sustainability, response in subgroups of patients, safety and tolerability, and cost-effectiveness. We will also summarize our limited real-world experience with one of the CGRP/rec mAbs. Although methodological differences and lack of direct comparative trials preclude any reliable comparison, the overall impression is that there are only minor differences in efficacy and tolerability profiles between the four monoclonals: the average placebo-subtracted 50% responder rates for reduction in migraine headaches are 21.4% in episodic migraine (NNTs: 4-5), 17.4% in chronic migraine (NNTs: 4-8). Patients with an improvement exceeding 50% are rare, chronic migraineurs with continuous headache are unlikely to be responders and migraine auras are not improved. The effect starts within the first week after administration and is quasi maximal at one month. It is sustained for long time periods and may last for several months after treatment termination. CGRP/rec mAbs are effective even after prior preventive treatment failures and in patients with medication overuse, but the effect size might be smaller. They significantly reduce disability and health care resource utilization. The adverse effect profile of CGRP/rec mAbs is close to that of placebo with few minor exceptions and despite concerns related to the safeguarding role of CGRP in ischemia, no treatment-related vascular adverse events have been reported to date. Putting the CGRP/rec mAbs in perspective with available preventive migraine drug treatments, their major advantage seems not to be chiefly their superior efficacy but their unprecedented efficacy over adverse event ratio. Regarding cost-effectiveness, preliminary pharmaco-economic analyses of erenumab suggest that it is cost-effective for chronic migraine compared to no treatment or to onabotulinumtoxinA, but likely not for episodic migraine unless attack frequency is high, indirect costs are considered and its price is lowered.

A CGRP receptor antagonist peptide formulated for nasal administration to treat migraine

OBJECTIVES

To investigate the formulation of the peptide-based antagonist (³⁴ Pro,³⁵ Phe)CGRP_27-37 , of the human calcitonin gene-related peptide (CGRP) receptor as a potential nasally delivered migraine treatment.

METHODS

Peptide sequences were prepared using automated methods and purified by preparative HPLC. Their structure and stability were determined by LC-MS. Antagonist potency was assessed by measuring CGRP-stimulated cAMP accumulation in SK-N-MC, cells and in CHO cells overexpressing the human CGRP receptor. In vivo activity was tested in plasma protein extravasation (PPE) studies using Evans blue dye accumulation. Peptide-containing chitosan microparticles were prepared by spray drying.

KEY FINDINGS

(³⁴ Pro,³⁵ Phe)CGRP_27-37 exhibited a 10-fold increased affinity compared to αCGRP_27-37 . Administration of (³⁴ Pro,³⁵ Phe)CGRP_27-37 to mice led to a significant decrease in CGRP-induced PPE confirming antagonistic properties in vivo. There was no degradation of (³⁴ Pro,³⁵ Phe)CGRP_27-37 and no loss of antagonist potency during formulation and release from chitosan microparticles.

CONCLUSIONS

(³⁴ Pro,³⁵ Phe)CGRP_27-37 is a potent CGRP receptor antagonist both in vitro and in vivo, and it can be formulated as a dry powder with no loss of activity indicating its potential as a nasally formulated anti-migraine medicine.

Placebo and nocebo phenomena in anti- CGRP monoclonal antibody trials for migraine prevention: a meta-analysis

High placebo and low nocebo phenomena mirror high positive expectations for a novel treatment, among other reasons. In a meta-analysis aimed to identify placebo and nocebo phenomena in the placebo-controlled randomized trials (RCTs) with the monoclonal antibodies targeting the calcitonin gene-related peptide pathway (anti-CGRP mAbs) all the placebo-treated patients were pooled and compared with the placebo-treated patients in RCTs with topiramate and onabotulinum toxin A (OBTA). In episodic migraine (EM), the proportion of placebo-treated patients who achieved the 50% responder rate (placebo) was 32.7% (95% CI 28.6%-37.0%) in anti-CGRP mAbs vs. 24.4% (95% CI 20.5%-28.5%) in topiramate trials. The proportion of dropouts due to adverse events in placebo-treated patients (nocebo) was 1.9% (95% CI 1.4%-2.6%) in anti-CGRP mAbs vs. 9.9% (95% CI 7.7%-12.3%) in topiramate RCTs. In chronic migraine (CM), the placebo 50% responder rate was 23.6% (95% CI 11.2%-38.8%) in anti-CGRP mAbs RCTs vs. 36.4% (95% CI 32.6%-39.3%) in RCTs with OBTA. The nocebo dropout in anti-CGRP mAbs and OBTA RCTs was 1.4% (95% CI 0.8%-2.1%) and 0.9 (95% CI 0.3%-1.7%), respectively. The stronger placebo and weaker nocebo phenomena in RCTs with anti-CGRP mAbs vs. those with topiramate in the prophylaxis of EM, may decisively determine anti-CGRP mAbs treatment success. No differences were detected between the anti-CGRP mAbs and OBTA in the treatment of CM.

Consensus of the Hellenic Headache Society on the diagnosis and treatment of migraine

More than 0.6 million people suffer from disabling migraines in Greece causing a dramatic work loss, but only a small proportion of migraineurs attend headache centres, most of them being treated by non-experts. On behalf of the Hellenic Headache Society, we report here a consensus on the diagnosis and treatment of adult migraine that is based on the recent guidelines of the European Headache Federation, on the principles of Good Clinical Practice and on the Greek regulatory affairs. The purposes are three-fold: (1) to increase awareness for migraine in Greece; (2) to support Greek practitioners who are treating migraineurs; and (3) to help Greek migraineurs to get the most appropriate treatment. For mild migraine, symptomatic treatment with high dose simple analgesics is suggested, while for moderate to severe migraines triptans or non-steroidal anti-inflammatory drugs, or both, should be administered following an individually tailored therapeutic strategy. A rescue acute treatment option should always be advised. For episodic migraine prevention, metoprolol (50–200 mg/d), propranolol (40–240 mg/d), flunarizine (5–10 mg/d), valproate (500–1800 mg/d), topiramate (25–100 mg/d) and candesartan (16–32 mg/d) are the drugs of first choice. For chronic migraine prevention topiramate (100-200 mg/d), valproate (500–1800 mg/d), flunarizine (5–10 mg/d) and venlafaxine (150 mg/d) may be used, but the evidence is very limited. Botulinum toxin type A and monoclonal antibodies targeting the CGRP pathway (anti-CGRP mAbs) are recommended for patients suffering from chronic migraine (with or without medication overuse) who failed or did not tolerate two previous treatments. Anti-CGRP mAbs are also suggested for patients suffering from high frequency episodic migraine (≥8 migraine days per month and less than 14) who failed or did not tolerate two previous treatments.

Recent Advances in Pharmacotherapy for Migraine Prevention: From Pathophysiology to New Drugs

Migraine is a common and disabling neurological disorder, with a significant socioeconomic burden. Its pathophysiology involves abnormalities in complex neuronal networks, interacting at different levels of the central and peripheral nervous system, resulting in the constellation of symptoms characteristic of a migraine attack. Management of migraine is individualised and often necessitates the commencement of preventive medication. Recent advancements in the understanding of the neurobiology of migraine have begun to account for some parts of the symptomatology, which has led to the development of novel target-based therapies that may revolutionise how migraine is treated in the future. This review will explore recent advances in the understanding of migraine pathophysiology, and pharmacotherapeutic developments for migraine prevention, with particular emphasis on novel treatments targeted at the calcitonin gene-related peptide (CGRP) pathway.

Calcitonin gene-related peptide monoclonal antibodies for migraine prevention: comparisons across randomized controlled studies

PURPOSE OF REVIEW

The results of phase 2 randomized controlled trials for the prevention of episodic and chronic migraine demonstrating the efficacy and safety of four mAbs targeting the calcitonin gene-related peptide (CGRP) pathway [ALD403 (eptinezumab), AMG334 (erenumab), LY2951742 (galcanezumab) and TEV48125 (fremanezumab)] have been published recently, and phase 3 trials are in process. This development will change headache management fundamentally. We aim to summarize and compare the phase 2 data.

RECENT FINDINGS

The change from baseline in the number of migraine days at the end of treatment in high-frequency episodic migraine was -1 (at weeks 5-8), -1.1 (at weeks 9-12), -1.2 (at weeks 9-12) and -2.6 (at weeks 9-12) days for ALD403, AMG344, LY2951742 and TEV48125 (225 mg), respectively. Number needed to treats for responders and odds ratio for any adverse event were 4.7, 6.2, 4.0 and 4.0 and 1.09, 0.96, 1.07 and 1.05, respectively.

SUMMARY

All four CGRP antibodies display comparable efficacy that does not differ significantly from that of the currently available oral antimigraine drugs. However, their safety and tolerability profiles as well as low frequency of administration looks promising but remains to be verified in long-term and large-scale trials. Considerations related to pregnancy, risk for cardiovascular effects and cost are subject for further evaluation.

Calcitonin gene-related peptide receptor as a novel target for the management of people with episodic migraine: current evidence and safety profile of erenumab

Migraine is a highly disabling neurological condition, and preventative treatment still remains problematic, due to aspecificity of the majority of the currently available prophylactic drugs. Calcitonin-gene-related peptide (CGRP) plays a crucial role in migraine pathophysiology; agents aimed at blocking its activity have, therefore, been developed in recent years, among which are monoclonal antibodies (mAbs) against CGRP, to prevent migraine. Erenumab is the only mAb that targets the CGRP receptor instead of the ligand, with high specificity and affinity of binding. This review will report on the most recent data on erenumab characteristics and on the results of clinical trials on its employment in the prevention of episodic migraine (4–14 monthly migraine days): one Phase II and two Phase III trials (completed) and one Phase III trial (ongoing). Monthly subcutaneous administration (70 mg or 140 mg) of erenumab vs placebo for 3–6 months showed significantly higher efficacy in reducing the mean monthly number of migraine days and the use of migraine-specific medication, and in decreasing physical impairment and impact of migraine on everyday activities (P<0.001). A favorable safety profile was demonstrated by the lack of significant differences in the occurrence of adverse events in erenumab-treated vs placebo-treated patients. Global results so far obtained point to erenumab as a new promising candidate for the preventative treatment of episodic migraine. Licence applications for erenumab were recently submitted to the Food and Drug Administration in the USA and European Medicines Agency in Europe (May/June 2017).

Patients' preferences for headache acute and preventive treatment

Background

We aimed to explore patients’ preferences for headache treatments with a self-administered questionnaire including the Q-No questionnaire for nocebo.

Methods

Questionnaires from 514 outpatients naïve to neurostimulation and monoclonal antibodies were collected.

Results

Patients assessed that the efficacy of a treatment is more important than safety or route of administration. They preferred to use an external neurostimulation device for both acute (67.1%) and preventive treatment (62.8%). Most patients preferred to take a pill (86%) than any other drug given parenterally for symptomatic pharmaceutical treatment. For preventive pharmaceutical treatment, most patients preferred to take a pill once per day (52%) compared to an injection either subcutaneously or intravenously each month (9% and 4%), or three months (15% and 11%). 56.6% of all participants scored more than 15 in Q-No questionnaire indicating potential nocebo behaviors that contributed significantly in their choices.

Conclusion

These patient preferences along with efficacy and safety data may help physicians better choose the right treatment for the right person.

The Molecular Fingerprint of Dorsal Root and Trigeminal Ganglion Neurons

The dorsal root ganglia (DRG) and trigeminal ganglia (TG) are clusters of cell bodies of highly specialized sensory neurons which are responsible for relaying information about our environment to the central nervous system. Despite previous efforts to characterize sensory neurons at the molecular level, it is still unknown whether those present in DRG and TG have distinct expression profiles and therefore a unique molecular fingerprint. To address this question, we isolated lumbar DRG and TG neurons using fluorescence-activated cell sorting from Advillin-GFP transgenic mice and performed RNA sequencing. Our transcriptome analyses showed that, despite being overwhelmingly similar, a number of genes are differentially expressed in DRG and TG neurons. Importantly, we identified 24 genes which were uniquely expressed in either ganglia, including an arginine vasopressin receptor and several homeobox genes, giving each population a distinct molecular fingerprint. We compared our findings with published studies to reveal that many genes previously reported to be present in neurons are in fact likely to originate from other cell types in the ganglia. Additionally, our neuron-specific results aligned well with a dataset examining whole human TG and DRG. We propose that the data can both improve our understanding of primary afferent biology and help contribute to the development of drug treatments and gene therapies which seek targets with unique or restricted expression patterns.

Prophylaxis of migraine headaches with riboflavin: A systematic review

WHAT IS KNOWN AND OBJECTIVE

Migraine headache is a relatively common, debilitating condition that costs our healthcare system over 78 billion dollars per year. Riboflavin has been advocated as a safe, effective prophylactic therapy for the prevention of migraines. The purpose of this study was to provide a systematic review of the current role of riboflavin in the prophylaxis of migraine headache.

METHODS

A MEDLINE literature search inclusive of the dates 1966-2016 was performed using the search terms: riboflavin and migraine disorders. Excerpta Medica was searched from 1980 to 2016 using the search terms: riboflavin and migraine. Additionally, Web of Science was searched using the terms riboflavin and migraine inclusive of 1945-2016. Bibliographies of all relevant papers were reviewed for additional citations. We utilized the PRISMA guidelines to select English language, human, clinical trials of riboflavin as a single entity or in combination, review articles, and supporting pharmacokinetic and pharmacogenomic data assessing the efficacy and mechanism of riboflavin therapy in the prophylactic treatment of migraine headache.

RESULTS AND DISCUSSION

A total of 11 clinical trials reveal a mixed effect of riboflavin in the prophylaxis of migraine headache. Five clinical trials show a consistent positive therapeutic effect in adults; four clinical trials show a mixed effect in paediatric and adolescent patients, and two clinical trials of combination therapy have not shown benefit. Adverse reactions with riboflavin have generally been mild.

WHAT IS NEW AND CONCLUSION

Riboflavin is well tolerated, inexpensive and has demonstrated efficacy in the reduction of adult patient's migraine headache frequency. Additional data are needed, however, to resolve questions involving pharmacokinetic issues and pharmacogenomic implications of therapy.

Pharmacokinetic Variability of Drugs Used for Prophylactic Treatment of Migraine

In this review, we evaluate the variability in the pharmacokinetics of 11 drugs with established prophylactic effects in migraine to facilitate 'personalized medicine' with these drugs. PubMed was searched for 'single-dose' and 'steady-state' pharmacokinetic studies of these 11 drugs. The maximum plasma concentration was reported in 248 single-dose and 115 steady-state pharmacokinetic studies, and the area under the plasma concentration-time curve was reported in 299 single-dose studies and 112 steady-state pharmacokinetic studies. For each study, the coefficient of variation was calculated for maximum plasma concentration and area under the plasma concentration-time curve, and we divided the drug variability into two categories; high variability, coefficient of variation >40%, or low or moderate variability, coefficient of variation <40%. Based on the area under the plasma concentration-time curve in steady-state studies, the following drugs have high pharmacokinetic variability: propranolol in 92% (33/36), metoprolol in 85% (33/39), and amitriptyline in 60% (3/5) of studies. The following drugs have low or moderate variability: atenolol in 100% (2/2), valproate in 100% (15/15), topiramate in 88% (7/8), and naproxen and candesartan in 100% (2/2) of studies. For drugs with low or moderate pharmacokinetic variability, treatment can start without initial titration of doses, whereas titration is used to possibly enhance tolerability of topiramate and amitriptyline. The very high pharmacokinetic variability of metoprolol and propranolol can result in very high plasma concentrations in a small minority of patients, and those drugs should therefore be titrated up from a low initial dose, depending mainly on the occurrence of adverse events.

Effects of non-invasive vagus nerve stimulation on attack frequency over time and expanded response rates in patients with chronic cluster headache: a post hoc analysis of the randomised, controlled PREVA study

BACKGROUND

In the PREVention and Acute treatment of chronic cluster headache (PREVA) study, attack frequency reductions from baseline were significantly more pronounced with non-invasive vagus nerve stimulation plus standard of care (nVNS + SoC) than with SoC alone. Given the intensely painful and frequent nature of chronic cluster headache attacks, additional patient-centric outcomes, including the time to and level of therapeutic response, were evaluated in a post hoc analysis of the PREVA study.

FINDINGS

After a 2-week baseline phase, 97 patients with chronic cluster headache entered a 4-week randomised phase to receive nVNS + SoC (n = 48) or SoC alone (n = 49). All 92 patients who continued into a 4-week extension phase received nVNS + SoC. Compared with SoC alone, nVNS + SoC led to a significantly lower mean weekly attack frequency by week 2 of the randomised phase; the attack frequency remained significantly lower in the nVNS + SoC group through week 3 of the extension phase (P < 0.02). Attack frequencies in the nVNS + SoC group were significantly lower at all study time points than they were at baseline (P < 0.05). Response rates were significantly greater with nVNS + SoC than with SoC alone when response was defined as attack frequency reductions of ≥25%, ≥50%, and ≥75% from baseline (≥25% and ≥50%, P < 0.001; ≥75%, P = 0.009). The 100% response rate was 8% with nVNS + SoC and 0% with SoC alone.

CONCLUSIONS

Prophylactic nVNS led to rapid, significant, and sustained reductions in chronic cluster headache attack frequency within 2 weeks after its addition to SoC and was associated with significantly higher ≥25%, ≥50%, and ≥75% response rates than SoC alone. The rapid decrease in weekly attack frequency justifies a 4-week trial period to identify responders to nVNS, with a high degree of confidence, among patients with chronic cluster headache.

Diclofenac potassium for oral solution (CAMBIA®) in the acute management of a migraine attack: clinical evidence and practical experience

Migraine headache affects about 12% of Western populations and is the third most common disease worldwide (sixth in terms of disability). In 1993, triptans were introduced in the United States as a new treatment for managing migraine attacks, but their use is limited by lack of response and safety concerns in some patients. Treatment options for patients with migraine who fail or cannot tolerate triptans include switching to another medication or adding an adjunctive medication. Desirable characteristics reported by patients for acute treatment of migraine attacks include complete pain relief, fast onset of action, and no pain recurrence. Diclofenac is a nonsteroidal anti-inflammatory medication that has been established as effective for acute treatment of migraine by the American Headache Society based on available evidence. Diclofenac potassium for oral solution is rapidly absorbed, achieving maximal plasma concentrations in 15 min, which coincides with a rapid onset of effect. In a comparison of diclofenac potassium for oral solution with diclofenac potassium tablets, the solution achieved a significant reduction in headache intensity beginning at 15 min compared with 60 min for the tablet. Across randomized clinical trials, approximately 25% of patients were pain free 2 h after administration of diclofenac oral solution and the effects were maintained over a 24-h period. Diclofenac potassium for oral solution is well tolerated; the most common adverse events are dizziness and gastrointestinal complaints, with incidences similar to placebo. No serious adverse events have been reported in clinical trials of diclofenac potassium for oral solution in the acute treatment of migraine. Diclofenac oral solution may offer rapid and sustained pain relief for patients who do not achieve pain resolution with other medications. In addition, patients who experience central sensitization with allodynia may benefit from the cyclooxygenase-blocking activity of diclofenac, which is needed in this advanced phase of migraine.

Calcitonin gene-related peptide monoclonal antibody for preventive treatment of episodic migraine: A meta analysis

Calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs) have shown promise in the preventive treatment of migraine. Therefore, we performed a meta-analysis to evaluate the efficacy and safety of CGRP mAbs for preventive treatment of migraine. Database including Ovid-SP, Cochrane Library, Pubmed and Web of Science (ISI) were systematically searched up to April 2, 2016 for randomized controlled trials(RCTs) which were dealing with the efficacy and safety of CGRP mAbs for preventive treatment of episodic migraine. Cochrane collaboration's tool for assessing risk of bias was utilized for evaluating the bias and quality of RCTs. The data was analyzed by reviewer manager 5.2. Totally, 4 literatures matched the inclusion criteria, including 4 independent RCTs and 1198 patients. Among mentioned above, AMG334 is a monoclonal antibody against CGRP receptor, but ALD403, LY2951742 and TEV-48125 are monoclonal antibody against CGRP. We found that 7mg and 21mg AMG334 couldn't reduce the monthly migraine days from baseline to week 1-4/9-12. But 70mg AMG334 could reduce the monthly migraine days from baseline to week 9-12 (MD=-1.1, 95% CI=[-2.1,-0.2]; P=0.021) significantly, as compared with placebo. Meanwhile, after pooled estimate the efficacy of CGRP mAb against CGRP, we found that CGRP mAbs improved the decrease of monthly migraine days from baseline to week 1-4, as compared with placebo (WMD=1.62, 95% CI=[1.09,2.14], I²=0%, P<0.00001). And CGRP mAbs improved the decrease of monthly migraine days from baseline to week 9-12, no matter in single dose subgroup (WMD=1.83, 95%CI=[0.06,3.60], I²=69%,P=0.04) or in multiple doses subgroup (WMD=1.77, 95%CI=[0.40,3.14], I²=61%,P=0.01). And there were no difference in incidence of adverse events between CGRP mAb group and placebo group. In conclusion, CGRP mAbs was a safety and effective preventive treatment for episodic migraine.

Monoclonal antibodies for chronic pain: a practical review of mechanisms and clinical applications

Context

Monoclonal antibodies are being investigated for chronic pain to overcome the shortcomings of current treatment options.

Objective

To provide a practical overview of monoclonal antibodies in clinical development for use in chronic pain conditions, with a focus on mechanisms of action and relevance to specific classes.

Methods

Qualitative review using a systematic strategy to search for randomized controlled trials, systematic and nonsystematic (narrative) reviews, observational studies, nonclinical studies, and case reports for inclusion. Studies were identified via relevant search terms using an electronic search of MEDLINE via PubMed (1990 to June 2017) in addition to hand-searching reference lists of retrieved systematic and nonsystematic reviews.

Results

Monoclonal antibodies targeting nerve growth factor, calcitonin gene-related peptide pathways, various ion channels, tumor necrosis factor-α, and epidermal growth factor receptor are in different stages of development. Mechanisms of action are dependent on specific signaling pathways, which commonly involve those related to peripheral neurogenic inflammation. In clinical studies, there has been a mixed response to different monoclonal antibodies in several chronic pain conditions, including migraine, neuropathic pain conditions (e.g., diabetic peripheral neuropathy), osteoarthritis, chronic back pain, ankylosing spondylitis, and cancer. Adverse events observed to date have generally been mild, although further studies are needed to ensure safety of monoclonal antibodies in early stages of development, especially where there is an overlap with non-pain-related pathways. High acquisition cost remains another treatment limitation.

Conclusion

Monoclonal antibodies for chronic pain have the potential to overcome the limitations of current treatment options, but strategies to ensure their appropriate use need to be determined.

Development of CGRP-dependent pain and headache related behaviours in a rat model of concussion: Implications for mechanisms of post-traumatic headache

Background and objective Posttraumatic headache (PTH) is one of the most common, debilitating and difficult symptoms to manage after a mild traumatic brain injury, or concussion. However, the mechanisms underlying PTH remain elusive, in part due to the lack of a clinically relevant animal model. Here, we characterized for the first time, headache and pain-related behaviours in a rat model of concussion evoked by a mild closed head injury (mCHI) - the major type of military and civilian related trauma associated with PTH - and tested responses to current and novel headache therapies. Methods Concussion was induced in adult male rats using a weight-drop device. Characterization of headache and pain related behaviours included assessment of cutaneous tactile pain sensitivity, using von Frey monofilaments, and ongoing pain using the conditioned place preference or aversion (CPP/CPA) paradigms. Sensitivity to headache/migraine triggers was tested by exposing rats to low-dose glyceryl trinitrate (GTN). Treatments included acute systemic administration of sumatriptan and chronic systemic administration of a mouse anti-CGRP monoclonal antibody. Results Concussed rats developed cephalic tactile pain hypersensitivity that was resolved by two weeks post-injury and was ameliorated by treatment with sumatriptan or anti-CGRP monoclonal antibody. Sumatriptan also produced CPP seven days post mCHI, but not in sham animals. Following the resolution of the concussion-evoked cephalic hypersensitivity, administration of GTN produced a renewed and pronounced cephalic pain hypersensitivity that was inhibited by sumatriptan or anti-CGRP antibody treatment as well as a CGRP-dependent CPA. GTN had no effect in sham animals. Conclusions Concussion leads to the development of headache and pain-related behaviours, in particular sustained enhanced responses to GTN, that are mediated through a CGRP-dependent mechanism. Treatment with anti-CGRP antibodies may be a useful approach to treat PTH.

Neurovascular contributions to migraine: Moving beyond vasodilation

Migraine is the third most common disease worldwide, the most common neurological disorder, and one of the most common pain conditions. Despite its prevalence, the basic physiology and underlying mechanisms contributing to the development of migraine are still poorly understood and development of new therapeutic targets is long overdue. Until recently, the major contributing pathophysiological event thought to initiate migraine was cerebral and meningeal arterial vasodilation. However, the role of vasodilation in migraine is unclear and recent findings challenge its necessity. While vasodilation itself may not contribute to migraine, it remains possible that vessels play a role in migraine pathophysiology in the absence of vasodilation. Blood vessels consist of a variety of cell types that both release and respond to numerous mediators including growth factors, cytokines, adenosine triphosphate (ATP), and nitric oxide (NO). Many of these mediators have actions on neurons that can contribute to migraine. Conversely, neurons release factors such as norepinephrine and calcitonin gene-related peptide (CGRP) that act on cells native to blood vessels. Both normal and pathological events occurring within and between vascular cells could thus mediate bi-directional communication between vessels and the nervous system, without the need for changes in vascular tone. This review will discuss the potential contribution of the vasculature, specifically endothelial cells, to current neuronal mechanisms hypothesized to play a role in migraine. Hypothalamic activity, cortical spreading depression (CSD), and dural afferent input from the cranial meninges will be reviewed with a focus on how these mechanisms can influence or be impacted by blood vessels. Together, the data discussed will provide a framework by which vessels can be viewed as important potential contributors to migraine pathophysiology, even in light of the current uncertainty over the role of vasodilation in this disorder.

Chronic Migraine: An Update on Physiology, Imaging, and the Mechanism of Action of Two Available Pharmacologic Therapies

Several lines of research support the hypothesis that migraine is a spectrum of illness, with clinical symptoms that vary along a continuum from episodic migraine to chronic migraine. Physiologic changes may result in episodic migraine evolving into chronic migraine over months to years in susceptible individuals. With chronification, headache frequency increases, becoming more disabling and less responsive to therapy. Neurophysiologic and functional imaging research has reported that chronic migraine may be associated with severity‐specific metabolic, functional, and structural abnormalities in the brainstem. Without longitudinal studies, it is unclear whether these changes may represent a continuum of individual progression and/or are reversible. Furthermore, chronic migraine is associated with larger impairments in cortical processing of sensory stimuli when compared with episodic migraine, possibly caused by more pronounced cortical hyperexcitability.

Progressive changes in nociceptive thresholds and subsequent central sensitization due to recurrent migraine attacks in vulnerable individuals contribute to the chronic migraine state. This may result in changes to baseline neurologic function between headache attacks, evident in both electrophysiological and functional imaging research. Patients experiencing migraine chronification may report increased non‐headache pain, fatigue, psychiatric disorders (eg, depression, anxiety), gastrointestinal complaints, and other somatic conditions associated with their long‐term experience with migraine pain.

Recent research provides a foundation for differentiating episodic and chronic migraine based on neurophysiologic and neuroimaging tools. In this literature review, we consider these findings in the context of models designed to explain the physiology and progression of episodic migraine into chronic migraine, and consider treatment of chronic migraine in susceptible individuals. Advances in pharmacotherapy provide treatment options for chronic migraine. Of the currently available treatment options, only onabotulinumtoxinA and topiramate have received regulatory approval and have demonstrated efficacy in patients with chronic migraine, although the exact mechanisms of action are not fully elucidated.

Anti-CGRP monoclonal antibodies in migraine: current perspectives

Migraine is a highly disabling neurological pain disorder in which management is frequently problematic. Most abortive and preventative treatments employed are classically non-specific, and their efficacy and safety and tolerability are often unsatisfactory. Mechanism-based therapies are, therefore, needed. Calcitonin gene-related peptide (CGRP) is recognized as crucial in the pathophysiology of migraine, and new compounds that target the peptide have been increasingly explored in recent years. First tested were CGRP receptor antagonists; they proved effective in acute migraine treatment in several trials, but were discontinued due to liver toxicity in long-term administration. Monoclonal antibodies against CGRP (LY2951742, ALD-403, and LBR-101/TEV-48125) or its receptor (AMG334) were subsequently developed. As reviewed in this study, numerous phase 1 and 2 trials and preliminary results of phase 3 trials have shown a good safety/tolerability profile and efficacy in migraine prevention, especially in high frequent episodic and chronic forms. Being macromolecules, these mAbs are not suitable for oral administration; however, their intravenous or subcutaneous delivery can be performed at relatively low frequency-every month or even quarterly-which enhances patients' compliance. Although not all migraineurs respond to this treatment, and longer administration periods will be needed to assess long-term effects, the results so far obtained are extraordinarily promising. The future introduction of mAbs on the market will probably represent a turning point for prevention similar to that represented by triptans for abortive treatment in migraine.

The Cyclic Vomiting Syndrome Threshold: A Framework for Understanding Pathogenesis and Predicting Successful Treatments

Cyclic vomiting syndrome (CVS) is an uncommon, idiopathic disorder defined by recurrent, sudden-onset attacks of repetitive retching and vomiting that are separated by symptom-free intervals. CVS was long regarded as a disorder primarily experienced by children but is now known to present de novo in adulthood. Adult CVS has garnered more research attention over the past 20 years, and these efforts have identified some acute and prophylactic treatments for this disorder. However, CVS still lacks a unifying disease model, and this has hindered the development of new therapies. Here adult CVS is reframed as a neurogenic disorder, driven by various endophenotypic factors that shape patterns of activity within the neural circuits required for disease expression. The concept of the "CVS threshold" is put forth in parallel with exploring the remarkable similarity of adult CVS with features of chronic migraine, epilepsy, and panic disorder. Because of such shared neural mechanisms and overlapping endophenotypes, many therapies that have been developed for these other disorders could also be useful in managing CVS. This review seeks to achieve three primary aims: (1) to develop a comprehensive, explanatory framework for adult CVS pathogenesis, (2) to use this framework for identifying potentially novel therapies for CVS, and (3) to describe future research directions that are needed to move the field forward.

Migraine in the era of precision medicine

Migraine is a common neurovascular disorder in the neurologic clinics whose mechanisms have been explored for several years. The aura has been considered to be attributed to cortical spreading depression (CSD) and dysfunction of the trigeminovascular system is the key factor that has been considered in the pathogenesis of migraine pain. Moreover, three genes (CACNA1A, ATP1A2, and SCN1A) have come from studies performed in individuals with familial hemiplegic migraine (FHM), a monogenic form of migraine with aura. Therapies targeting on the neuropeptids and genes may be helpful in the precision medicine of migraineurs. 5-hydroxytryptamine (5-HT) receptor agonists and calcitonin gene-related peptide (CGRP) receptor antagonists have demonstrated efficacy in the acute specific treatment of migraine attacks. Therefore, ongoing and future efforts to find new vulnerabilities of migraine, unravel the complexity of drug therapy, and perform biomarker-driven clinical trials are necessary to improve outcomes for patients with migraine.