The role of CGRP in the pathophysiology of migraine and efficacy of CGRP receptor antagonists as acute antimigraine drugs

Provocation of attacks to discover migraine signaling mechanisms and new drug targets: early history and future perspectives - a narrative review

INTRODUCTION

The development of several experimental migraine provocation models has significantly contributed to an understanding of the signaling mechanisms of migraine. The early history of this development and a view to the future are presented as viewed by the inventor of the models.

METHODS

Extensive knowledge of the literature was supplemented by scrutiny of reference lists.

RESULTS

Early studies used methodologies that were not blinded. They suggested that histamine and nitroglycerin (Glyceryl trinitrate, GTN) could induce headache and perhaps migraine. The development of a double blind, placebo-controlled model, and the use of explicit diagnostic criteria for induced migraine was a major step forward. GTN, donor of nitric oxide (NO), induced headache in people with- and without migraine as well as delayed migraine attacks in those with migraine. Calcitonin gene-related peptide (CGRP) did the same, supporting the development of CGRP antagonists now widely used in patients. Likewise, pituitary adenylate cyclase activating peptide (PACAP) provoked headache and migraine. Recently a PACAP antibody has shown anti migraine activity in a phase 2 trial. Increase of second messengers activated by NO, CGRP and PACAP effectively induced migraine. The experimental models have also been used in other types of headaches and have been combined with imaging and biochemical studies. They have also been used for drug testing and in genetic studies.

CONCLUSION

Conclusion. Human migraine provocation models have informed about signaling mechanisms of migraine leading to new drugs and drug targets. Future use of these models in imaging-, biochemistry- and genetic studies as well as in the further study of animal models is promising.

Anti-calcitonin Gene-Related Peptide Monoclonal Antibodies in Migraine: Focus on Clinical Pharmacokinetics

The calcitonin gene-related peptide transmission was the target for recent development of drugs that effectively prevent attacks of both episodic and chronic migraine. The aim of this narrative review was to offer deeper insight into pharmacokinetics of monoclonal antibodies approved for prevention of migraine attacks. For this narrative review, relevant literature was searched for in MEDLINE and Google Scholar databases, covering periods 1966-2023 and 2006-2023, respectively. The ClinicalTrials.gov database was also searched for relevant clinical studies whose results had not been published previously in medical journals, covering the period 2000-2023. The monoclonal antibodies from this group are distributed mainly in the plasma and part of the extracellular space; they are neither metabolized in the liver nor excreted via the kidneys. The elimination of galcanezumab, eptinezumab and fremanezumab takes place only by a non-specific linear process via the reticuloendothelial system in the liver, while erenumab is eliminated by a non-specific process and by a specific, saturable process because of binding to receptors located on the cell membrane. Since the elimination processes do not have a large capacity, the half-life is about 2 weeks for erenumab and about 4 weeks for other monoclonal antibodies. Variability in the pharmacokinetics of these monoclonal antibodies is small in different subpopulations, and body weight is the only parameter to consider when choosing the dose of these drugs.

Is calcitonin gene-related peptide (CGRP) the missing link in food histamine-induced migraine? A review of functional gut-to-trigeminovascular system connections

Calcitonin gene-related peptide (CGRP) and histamine plasma concentrations increase during migraine attacks. Both mediators are potent vasodilators, and they have been shown to reciprocally contribute to the release of each other in the trigeminovascular system, possibly driving migraine development. A high-histamine-content diet triggers migraine in patients who have histamine degradation deficiency owing to diaminooxidase (DAO) gene mutations. Therefore, studying functional links between exogenous histamine and CGRP seems promising for the understanding of diet-induced migraine generation. Notably, there is a lack of knowledge about the interplay of the enteric nervous system and the spinal/trigeminal somatosensory system with regard to CGRP and histamine. Based on background evidence, we propose that a functional interconnection between exogenous histamine and CGRP contributes to migraine development.

Efficacy of migraine prophylaxis treatments for treatment-naïve patients and those with prior treatment failure: a protocol for systematic review and network meta-analysis of randomised controlled trials

INTRODUCTION

Migraine headache is a significant health problem affecting patients' psychological well-being and quality of life. Several network meta-analyses (NMAs) have compared the efficacy of migraine prophylaxis medications. However, some have focused exclusively on oral medications, while others were limited to injectable medications. Moreover, none of these NMAs conducted a stratified analysis between treatment-naïve patients and those with prior treatment failure. Therefore, this systematic review and NMA will compare the efficacy among all treatments for migraine prophylaxis, stratified by the treatment status of patients (ie, treatment-naïve and previous treatment failure).

METHODS AND ANALYSIS

Randomised-controlled trials that included patients with chronic or episodic migraine, assessed the efficacy of oral or injectable treatments for migraine prophylaxis and measured the outcomes as monthly migraine day, monthly headache day, migraine-related disability, health-related quality of life or adverse drug events will be eligible for inclusion in this review. Relevant studies will be searched from Medline, Scopus, the US National Institutes of Health Register, and the World Health Organization International Clinical Trials Registry Platform (WHO-ICTRP) databases since inception through 15 August 2023. Risk of bias assessment will be performed using a revised tool for assessing the risk of bias in randomised trials. Two-stage NMA will be applied to compare relative treatment effects among all treatments of migraine prophylaxis. Surface under the cumulative ranking curve will be applied to estimate and rank the probability to be the best treatment. Consistency assumption will be assessed using a design-by-treatment interaction model. Publication bias will be assessed by comparison-adjusted funnel plot. All analyses will be stratified according to patients' status (ie, treatment-naïve and prior treatment failure).

ETHICS AND DISSEMINATION

This study is a systematic review protocol collecting data from published literature and does not require approval from an institutional review board. Results from this systematic review will be published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42020171843.

Drug-related side effects and adverse reactions in the treatment of migraine: a bibliometric and visual analysis

Background

Migraine imposes a substantial global burden, impacting patients and society. Pharmacotherapy, as a primary treatment, entails specific adverse reactions. Emphasizing these reactions is pivotal for improving treatment strategies and enhancing patients' well-being. Thus, we conducted a comprehensive bibliometric and visual analysis of relevant literature.

Methodology

We conducted a comprehensive search on the Science Citation Index Expanded within the Web of Science, restricting the literature for analysis based on criteria such as document type, publication date, and language. Subsequently, we utilized various analytical tools, including VOSviewer, Scimago Graphica, the R package 'bibliometrix', CiteSpace, and Excel programs, for a meticulous examination and systematic organization of data concerning journals, authors, countries/regions, institutions, keywords, and references.

Results

By August 31, 2023, the literature was distributed across 379 journals worldwide, authored by 4,235 individuals from 1726 institutions. It featured 2,363 keywords and 38,412 references. 'HEADACHE' led in publication count, with 'SILBERSTEIN S' as the most prolific author. The United States ranked highest in publication volume, with 'UNIV COPENHAGEN' leading among institutions.

Conclusion

Our research findings indicate that researchers in the field continue to maintain a focus on the calcitonin gene-related peptide (CGRP) system and explore diverse mechanisms for drug development through the application of novel biotechnological approaches. Furthermore, it is imperative to enhance the assessment of clinical trial outcomes, consistently monitor the efficacy and safety of prominent drugs such as Erenumab and Fremanezumab. There is a need for further evaluation of acute and preventive treatments tailored to different populations and varying types of migraine.

Effects of CYP3A4 inhibition/induction and OATP inhibition on the pharmacokinetics of atogepant in healthy adults

Aim: Atogepant, a calcitonin gene-related peptide (CGRP) receptor antagonist, is a substrate of OATP and metabolized by CYP3A4. Effect of multiple-dose itraconazole (strong CYP3A4 inhibitor), single-dose rifampin (strong OATP inhibitor) and multiple-dose rifampin (strong CYP3A4 inducer) on single-dose pharmacokinetics (PK) and safety of atogepant were assessed. Methods: Two phase I, open-label, single-center, crossover trials enrolled healthy adults. Results: Cmax and AUC of atogepant increased when co-administered with itraconazole. Atogepant systemic exposure increased following co-administration with single-dose rifampin. Atogepant systemic exposure decreased with co-administration of multiple-dose rifampin. Treatment emergent adverse events (TEAEs) were predominantly mild or moderate, and included constipation, dizziness, headache and nauseas. Conclusion: Systemic exposure of atogepant increased significantly when co-administered with a strong CYP3A4 or OATP inhibitor and decreased significantly when co-administered with a strong CYP3A4 inducer.

Galcanezumab in patients with episodic migraine: results from the open-label period of the phase 3 PERSIST study

BACKGROUND

The phase 3 randomized PERSIST study demonstrated the efficacy and tolerability of galcanezumab, a humanized anti-calcitonin gene-related peptide (CGRP) monoclonal antibody for prevention of episodic migraines. We present findings from the open-label extension (OLE) of PERSIST, which evaluated the long-term efficacy and safety of galcanezumab in patients from China, India, and Russia.

METHODS

Patients completing the 3-month double-blind period of PERSIST were eligible for the 3-month OLE. Patients previously randomized to galcanezumab (GMB/GMB group) continued to receive galcanezumab 120 mg at all three visits during the OLE whereas patients randomized to placebo received a 240 mg loading dose of galcanezumab and then two 120 mg doses (PBO/GMB group). The primary outcome was the mean change (from double-blind baseline) in the number of monthly migraine headache days (MHDs) to month 6. Other endpoints included percent reduction in monthly MHDs from double-blind baseline to month 6, functional outcomes, safety and tolerability.

RESULTS

Overall, 99% of patients completing the double-blind period entered the OLE, and 96% completed through month 6. Patients in the GMB/GMB group achieved continued improvements in efficacy, with the reduction from baseline in the mean number of monthly MHDs, and slightly increasing from 4.01 days at the end of the double-blind period to 4.62 at the end of the OLE. Of patients who were ≥ 50% responders to galcanezumab at month 3, 66% maintained this response through to month 6. Patients in the PBO/GMB group experienced a rapid reduction in the number of monthly MHDs after initiation of galcanezumab, with a mean reduction from baseline of 4.56 days by month 6. The long-term benefits of galcanezumab were also supported by improvements in other efficacy and functional endpoints. All safety findings were consistent with the known long-term safety profile of galcanezumab; no patients experienced a treatment-related serious adverse event.

CONCLUSIONS

Galcanezumab was efficacious and well-tolerated in patients with episodic migraine from China, India and Russia, for up to 6 months.

TRIAL REGISTRATION

ClinicalTrisABSTRACT_pals.gov NCT03963232, registered May 24, 2019.

Blocking the CGRP Receptor: Differences across Human Vascular Beds

Multiple drugs targeting the calcitonin gene-related peptide (CGRP) receptor have been developed for the treatment of migraine. Here, the effect of the small-molecule CGRP receptor antagonist zavegepant (0.1 nM-1 µM) on CGRP-induced relaxation in isolated human coronary arteries (HCAs) was investigated. A Schild plot was constructed and a pA2 value was calculated to determine the potency of zavegepant. The potency and Schild plot slopes of atogepant, olcegepant, rimegepant, telcagepant, ubrogepant and zavegepant in HCAs and human middle meningeal arteries (HMMAs), obtained from our earlier studies, were compared. Zavegepant shifted the concentration-response curve to CGRP in HCAs. The corresponding Schild plot slope was not different from unity, resulting in a pA2 value of 9.92 ± 0.24. No potency difference between HCAs and HMMAs was observed. Interestingly, olcegepant, atogepant and rimegepant, with a Schild plot slope < 1 in HCAs, were all >1 log unit more potent in HMMAs than in HCAs, while telcagepant, ubrogepant and zavegepant, with a Schild plot slope not different from unity, showed similar (<1 log difference) potency across both tissues. As a Schild plot slope < 1 may point to the involvement of multiple receptors, it is important to further identify the receptors involved in the relaxation to CGRP in HCAs, which may be used to improve the cardiovascular safety of future antimigraine drugs.

Non-pharmacological interventions for prophylaxis of vestibular migraine

BACKGROUND

Vestibular migraine is a form of migraine where one of the main features is recurrent attacks of vertigo. These episodes are often associated with other features of migraine, including headache and sensitivity to light or sound. These unpredictable and severe attacks of vertigo can lead to a considerable reduction in quality of life. The condition is estimated to affect just under 1% of the population, although many people remain undiagnosed. A number of interventions have been used, or proposed to be used, as prophylaxis for this condition, to help reduce the frequency of the attacks. Many of these interventions include dietary, lifestyle or behavioural changes, rather than medication.  OBJECTIVES: To assess the benefits and harms of non-pharmacological treatments used for prophylaxis of vestibular migraine.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 23 September 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in adults with definite or probable vestibular migraine comparing dietary modifications, sleep improvement techniques, vitamin and mineral supplements, herbal supplements, talking therapies, mind-body interventions or vestibular rehabilitation with either placebo or no treatment. We excluded studies with a cross-over design, unless data from the first phase of the study could be identified.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome - improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease-specific health-related quality of life, 5) improvement in headache, 6) improvement in other migrainous symptoms and 7) other adverse effects. We considered outcomes reported at three time points: < 3 months, 3 to < 6 months, > 6 to 12 months. We used GRADE to assess the certainty of evidence for each outcome.  MAIN RESULTS: We included three studies in this review with a total of 319 participants. Each study addressed a different comparison and these are outlined below. We did not identify any evidence for the remaining comparisons of interest in this review.   Dietary interventions (probiotics) versus placebo We identified one study with 218 participants (85% female). The use of a probiotic supplement was compared to a placebo and participants were followed up for two years. Some data were reported on the change in vertigo frequency and severity over the duration of the study. However, there were no data regarding improvement of vertigo or serious adverse events. Cognitive behavioural therapy (CBT) versus no intervention One study compared CBT to no treatment in 61 participants (72% female). Participants were followed up for eight weeks. Data were reported on the change in vertigo over the course of the study, but no information was reported on the proportion of people whose vertigo improved, or on the occurrence of serious adverse events.  Vestibular rehabilitation versus no intervention The third study compared the use of vestibular rehabilitation to no treatment in a group of 40 participants (90% female) and participants were followed up for six months. Again, this study reported some data on change in the frequency of vertigo during the study, but no information on the proportion of participants who experienced an improvement in vertigo or the number who experienced serious adverse events.  We are unable to draw meaningful conclusions from the numerical results of these studies, as the data for each comparison of interest come from single, small studies and the certainty of the evidence was low or very low.  AUTHORS' CONCLUSIONS: There is a paucity of evidence for non-pharmacological interventions that may be used for prophylaxis of vestibular migraine. Only a limited number of interventions have been assessed by comparing them to no intervention or a placebo treatment, and the evidence from these studies is all of low or very low certainty. We are therefore unsure whether any of these interventions may be effective at reducing the symptoms of vestibular migraine and we are also unsure whether they have the potential to cause harm.

Pharmacological interventions for prophylaxis of vestibular migraine

BACKGROUND

Vestibular migraine is a form of migraine where one of the main features is recurrent attacks of vertigo. These episodes are often associated with other features of migraine, including headache and sensitivity to light or sound. These unpredictable and severe attacks of vertigo can lead to a considerable reduction in quality of life. The condition is estimated to affect just under 1% of the population, although many people remain undiagnosed. A number of pharmacological interventions have been used or proposed to be used as prophylaxis for this condition, to help reduce the frequency of the attacks. These are predominantly based on treatments that are in use for headache migraine, with the belief that the underlying pathophysiology of these conditions is similar.

OBJECTIVES

To assess the benefits and harms of pharmacological treatments used for prophylaxis of vestibular migraine.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 23 September 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in adults with definite or probable vestibular migraine comparing beta-blockers, calcium channel blockers, antiepileptics, antidepressants, diuretics, monoclonal antibodies against calcitonin gene-related peptide (or its receptor), botulinum toxin or hormonal modification with either placebo or no treatment. We excluded studies with a cross-over design, unless data from the first phase of the study could be identified.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome - improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease-specific health-related quality of life, 5) improvement in headache, 6) improvement in other migrainous symptoms and 7) other adverse effects. We considered outcomes reported at three time points: < 3 months, 3 to < 6 months, > 6 to 12 months. We used GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We included three studies with a total of 209 participants. One evaluated beta-blockers and the other two evaluated calcium channel blockers. We did not identify any evidence for the remaining interventions of interest. Beta-blockers versus placebo One study (including 130 participants, 61% female) evaluated the use of 95 mg metoprolol once daily for six months, compared to placebo. The proportion of people who reported improvement in vertigo was not assessed in this study. Some data were reported on the frequency of vertigo attacks at six months and the occurrence of serious adverse effects. However, this is a single, small study and for all outcomes the certainty of evidence was low or very low. We are unable to draw meaningful conclusions from the numerical results. Calcium channel blockers versus no treatment Two studies, which included a total of 79 participants (72% female), assessed the use of 10 mg flunarizine once daily for three months, compared to no intervention. All of the evidence for this comparison was of very low certainty. Most of our outcomes were only reported by a single study, therefore we were unable to conduct any meta-analysis. Some data were reported on improvement in vertigo and change in vertigo, but no information was available regarding serious adverse events. We are unable to draw meaningful conclusions from the numerical results, as these data come from single, small studies and the certainty of the evidence was very low.

AUTHORS CONCLUSIONS

There is very limited evidence from placebo-controlled randomised trials regarding the efficacy and potential harms of pharmacological interventions for prophylaxis of vestibular migraine. We only identified evidence for two of our interventions of interest (beta-blockers and calcium channel blockers) and all evidence was of low or very low certainty. Further research is necessary to identify whether these treatments are effective at improving symptoms and whether there are any harms associated with their use.

Pharmacological interventions for acute attacks of vestibular migraine

BACKGROUND

Vestibular migraine is a form of migraine where one of the main features is recurrent attacks of vertigo. These episodes are often associated with other features of migraine, including headache and sensitivity to light or sound. The unpredictable and severe attacks of vertigo can lead to a considerable reduction in quality of life. The condition is estimated to affect just under 1% of the population, although many people remain undiagnosed. A number of pharmacological interventions have been used, or proposed to be used, at the time of a vestibular migraine attack to help reduce the severity or resolve the symptoms. These are predominantly based on treatments that are in use for headache migraine, with the belief that the underlying pathophysiology of these conditions is similar.  OBJECTIVES: To assess the benefits and harms of pharmacological interventions used to relieve acute attacks of vestibular migraine.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 23 September 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs in adults with definite or probable vestibular migraine comparing triptans, ergot alkaloids, dopamine antagonists, antihistamines, 5-HT3 receptor antagonists, gepants (CGRP receptor antagonists), magnesium, paracetamol or non-steroidal anti-inflammatory drugs (NSAIDs) with either placebo or no treatment.  DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were: 1) improvement in vertigo (assessed as a dichotomous outcome - improved or not improved), 2) change in vertigo (assessed as a continuous outcome, with a score on a numerical scale) and 3) serious adverse events. Our secondary outcomes were: 4) disease-specific health-related quality of life, 5) improvement in headache, 6) improvement in other migrainous symptoms and 7) other adverse effects. We considered outcomes reported at three time points: < 2 hours, 2 to 12 hours, > 12 to 72 hours. We used GRADE to assess the certainty of evidence for each outcome.  MAIN RESULTS: We included two RCTs with a total of 133 participants, both of which compared the use of triptans to placebo for an acute attack of vestibular migraine. One study was a parallel-group RCT (of 114 participants, 75% female). This compared the use of 10 mg rizatriptan to placebo. The second study was a smaller, cross-over RCT (of 19 participants, 70% female). This compared the use of 2.5 mg zolmitriptan to placebo.  Triptans may result in little or no difference in the proportion of people whose vertigo improves at up to two hours after taking the medication. However, the evidence was very uncertain (risk ratio 0.84, 95% confidence interval 0.66 to 1.07; 2 studies; based on 262 attacks of vestibular migraine treated in 124 participants; very low-certainty evidence). We did not identify any evidence on the change in vertigo using a continuous scale. Only one of the studies assessed serious adverse events. No events were noted in either group, but as the sample size was small we cannot be sure if there are risks associated with taking triptans for this condition (0/75 receiving triptans, 0/39 receiving placebo; 1 study; 114 participants; very low-certainty evidence).  AUTHORS' CONCLUSIONS: The evidence for interventions used to treat acute attacks of vestibular migraine is very sparse. We identified only two studies, both of which assessed the use of triptans. We rated all the evidence as very low-certainty, meaning that we have little confidence in the effect estimates and cannot be sure if triptans have any effect on the symptoms of vestibular migraine. Although we identified sparse information on potential harms of treatment in this review, the use of triptans for other conditions (such as headache migraine) is known to be associated with some adverse effects.  We did not identify any placebo-controlled randomised trials for other interventions that may be used for this condition. Further research is needed to identify whether any interventions help to improve the symptoms of vestibular migraine attacks and to determine if there are side effects associated with their use.

CGRP physiology, pharmacology, and therapeutic targets: migraine and beyond

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse physiological functions. Its two isoforms (α and β) are widely expressed throughout the body in sensory neurons as well as in other cell types, such as motor neurons and neuroendocrine cells. CGRP acts via at least two G protein-coupled receptors that form unusual complexes with receptor activity-modifying proteins. These are the CGRP receptor and the AMY1 receptor; in rodents, additional receptors come into play. Although CGRP is known to produce many effects, the precise molecular identity of the receptor(s) that mediates CGRP effects is seldom clear. Despite the many enigmas still in CGRP biology, therapeutics that target the CGRP axis to treat or prevent migraine are a bench-to-bedside success story. This review provides a contextual background on the regulation and sites of CGRP expression and CGRP receptor pharmacology. The physiological actions of CGRP in the nervous system are discussed, along with updates on CGRP actions in the cardiovascular, pulmonary, gastrointestinal, immune, hematopoietic, and reproductive systems and metabolic effects of CGRP in muscle and adipose tissues. We cover how CGRP in these systems is associated with disease states, most notably migraine. In this context, we discuss how CGRP actions in both the peripheral and central nervous systems provide a basis for therapeutic targeting of CGRP in migraine. Finally, we highlight potentially fertile ground for the development of additional therapeutics and combinatorial strategies that could be designed to modulate CGRP signaling for migraine and other diseases.

Migraine and obesity: what is the real direction of their association?

INTRODUCTION

In recent decades, studies have addressed the issue of how migraine and obesity are related and have suggested obesity as a risk factor for migraine headache. However, the exact direction of this relationship remains under debate. In this review, the authors summarize the evidence that have suggested migraine as a risk factor for obesity and overweightness.

AREAS COVERED

This article reviews the results of the previous research published on PubMed and Scopus databases (from 2000 to 2020) concerning the association between migraine and obesity to determine the actual direction of their association. Special attention has been given to the common mechanistic pathways involved in the pathophysiology of migraine and obesity.

EXPERT OPINION

The majority of research conducted thus far has considered obesity as a risk factor for migraine. However, because of the cross-sectional design of available research, we cannot be certain of the proposed direction of this association. There is evidence supporting the hypothesis that obesity can serve as a consequence of migraine through the effects of neuropeptides, inflammatory mediators, adipokines, gut microbiota and modifications in eating behavior and lifestyle. However, the real direction of the relationship between migraine and obesity should be further investigated in large prospective studies.

The Pathophysiological Relationship Between Migraine and SARS-CoV-2 Infection: A Comprehensive Literature Review

People with migraine, and individuals with other neurological conditions, have suffered in multiple aspects during the COVID-19 pandemic. This paper will discuss the factors that impacted the neurology department. The emergence of severe acute respiratory syndrome coronavirus 2 in late 2019 has generated new challenges in healthcare systems across the globe. Similar to the fields of pulmonology and cardiology that saw an increase in research, the neurology department was in search of possible relationships between COVID-19 and other medical conditions. Research on the possible common pathophysiological mechanism between COVID-19 and migraine is currently being studied. The most recent hypothesis suggests the following: migraine is caused by an increased release of calcitonin gene-related peptide from the trigeminal ganglion, which will cause an increase in nitric oxide and IL-1β, resulting in vasodilation and inducing hyperalgesia. COVID-19 causes an increase in nod-like receptor protein 3, which causes the production of IL-1β and again induces an inflammatory response. This review article looks at the mechanisms of migraine and COVID-19, and tries to link a common pathophysiological pathway between the two. This report also serves as a gateway for further research regarding possible management that could potentially target both of these mechanisms.

Examining Migraine as a Predictor of Benign Paroxysmal Positional Vertigo Onset, Severity, Recurrence, and Associated Falls

Introduction: The comorbidity of migraine and benign paroxysmal positional vertigo (BPPV) is well-established, yet the impact of migraine on the BPPV phenotype remains understudied.

Methods: A retrospective analysis of patients at a tertiary dizziness/vertigo clinic diagnosed with BPPV from 2015 and 2020 was conducted. The study's primary outcomes were the age of BPPV onset, Dizziness Handicap Index (DHI), BPPV recurrence, and dizziness-related falls.

Results: In our cohort of 255 BPPV patients, 44.7% had a history of migraine. Those with migraine had an earlier age of BPPV onset than individuals without migraine (60.2 vs. 65.4, p = 0.0018). Migraineurs and non-migraineurs did not differ in their DHI (44.7 vs. 41.6, p= 0.44), recurrence rates (48.3% vs. 40.4%, p= 0.21), and falls (32.5% vs. 37.6%, p = 0.39). Among individuals with horizontal canal BPPV, a higher proportion of migraineurs experienced falls than non-migraineurs (50.0% vs. 6.3%, p = 0.02).

Conclusions: Migraineurs experience BPPV at a younger age than those without migraine. This finding suggests that migraine, which has been shown to cause inner ear damage, predisposes individuals to developing BPPV earlier. Migraine was also associated with a higher rate of falls among patients with horizontal canal BPPV, indicating that a migraine history may impact the phenotype of BPPV.

Observations from a prospective small cohort study suggest that CGRP genes contribute to acute posttraumatic headache burden after concussion

Introduction

Post-traumatic headache (PTH) is commonly reported after concussion. Calcitonin gene-related peptide (CGRP) is implicated in the pathogenesis of migraine. We explored how single nucleotide polymorphisms (SNPs) from CGRP-alpha (CALCA) and the receptor activity modifying protein-1 (RAMP1) related to headache burden during the first week after concussion.

Methods

A prospective study was performed in 34 collegiate athletes who sustained a concussion. Participants completed the symptom evaluation checklist from the SCAT3 within 48 h of injury (V1), and again 4 (V2) and 7 (V3) days after injury. For each visit, the self-reported score (0–6) for headache, pressure in head, blurred vision, and sensitivity to light/noise were reported and summed to calculate the headache burden. A saliva sample was obtained and genotyped for CALCA (rs3781719) and RAMP1 (rs10185142). RAMP1 (TT, TC, CC) and CALCA (AA, AG, GG) were dichotomized (A+, A- and T+, T-, respectively), and concatenated (T+A+, T+A-, T-A+, T-A-) for analyses.

Results

Headache Burden at Visit 1 was greatest in T+A+ compared to T-A+, and trended toward a significant difference with T+A-. Repeated-measures ANOVA revealed the presence of significant visit main effects (p &lt; 0.001, η2 = 0.404), but the group (p = 0.055) and interaction effects only trended (p = 0.094). Pearson's χ2-tests revealed that 88% of those with return-to play (RTP) exclusions ≥15 days had PTH with multi-sensory symptoms (PTH+SENS) as compared to 35% in those with RTP &lt; 14 day.

Conclusion

Knowledge of RAMP1 and CALCA genotypes appear to improve an understanding the presenting features and magnitude of headache burden after concussion injury.

Pooled Analysis of Real-World Evidence Supports Anti-CGRP mAbs and OnabotulinumtoxinA Combined Trial in Chronic Migraine

OnabotulinumtoxinA, targeting the CGRP machinery, has been approved for the last two decades for chronic migraine prevention. The recently approved monoclonal antibodies (mAbs) directed towards the calcitonin gene-related peptide (CGRP) pathway open a new age for chronic migraine control. However, some 40% patients suffering from chronic migraine is still resistant to treatment. The aim of this work is to answer the following PICOS (participants intervention comparator outcome study design) question: Is there evidence of efficacy and safety of the combined administration of anti-CGRP mAbs and onabotulinumtoxinA in chronic migraine? A systematic review and meta-analysis [Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 recommendations] was made up to 19 April 2022. The results are encouraging: the combined treatment proved to afford ≥50% monthly headache days (MHDs)/frequency reduction respect to baseline in up to 58.8% of patients; in comparison, anti-CGRP mAbs reduce MHDs of 1.94 days from baseline and botulinum toxin of 1.86 days. Our study demonstrates for the first time that the combination therapy of onabotulinumtoxinA with anti-CGRP mAbs affords a reduction of 2.67 MHDs with respect to onabotulinumtoxinA alone, with moderate certainty of evidence. Adequately powered, good-quality studies are needed to confirm the response to combination therapy in terms of efficacy and safety. PROSPERO registration: CRD42022313640.

Galcanezumab in episodic migraine: the phase 3, randomized, double-blind, placebo-controlled PERSIST study

Background

Galcanezumab, a humanized monoclonal antibody that binds calcitonin gene-related peptide, has demonstrated efficacy and good tolerability in patients with episodic migraine in previous phase 3 trials. We report results from the PERSIST study, which was designed to assess the efficacy and safety of galcanezumab in patients with episodic migraine from China, India, and Russia.

Methods

This phase 3 study was conducted at 40 centers in China (n = 26), India (n = 10), and Russia (n = 4). Eligible adult patients with episodic migraine were randomized in a 1:1 ratio to receive monthly galcanezumab 120 mg (with 240 mg loading dose) or placebo during a double-blind, 3-month treatment period. The primary endpoint was the overall mean change from baseline in monthly migraine headache days (MHDs). Key secondary endpoints were the mean proportion of patients with ≥ 50%, ≥ 75%, and 100% reductions from baseline in MHDs and mean change in the Migraine-Specific Quality of Life Questionnaire (MSQ) Role Function-Restrictive domain score.

Results

In total, 520 patients were randomized and received at least one dose of galcanezumab (N = 261) or placebo (N = 259). The least squares (LS) mean reduction from baseline in monthly MHDs over 3 months was significantly greater with galcanezumab compared with placebo (-3.81 days vs. -1.99 days; p < 0.0001). Significantly greater mean proportions of patients with galcanezumab versus placebo had ≥ 50%, ≥ 75%, and 100% reductions from baseline in MHDs (all p < 0.0001). The overall mean improvement from baseline in MSQ Role Function-Restrictive score over 3 months was significantly greater with galcanezumab versus placebo (p < 0.0001). There were no clinically meaningful differences between the galcanezumab and placebo group on any safety parameters except for a higher incidence of injection site pruritus (5.0% vs. 0.0%), injection site reaction (3.8% vs. 0.4%), and injection site discomfort (2.3% vs. 0.0%). TEAEs related to injection sites were mild in severity, except in 1 patient who had a moderate injection site reaction. Six serious adverse events were reported by 6 patients (2 galcanezumab, 4 placebo).

Conclusions

Galcanezumab 120 mg once monthly was effective and well tolerated in patients with episodic migraine from China, India, and Russia.

Trial registration

ClinicalTrials.gov Identifier NCT03963232 (PERSIST), registered May 24, 2019.

Calcitonin gene-related peptide and neurologic injury: An emerging target for headache management

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide known to be involved in the trigeminovascular system and to function as a potent vasodilator. Although it has emerged as a viable target for headache management with targeted treatments developed for migraine, a highly disabling neurovascular disorder, less is known about CGRP's role in other neurologic conditions such as traumatic brain injury and subarachnoid hemorrhage. The literature has shown that during these injury cascades, CGRP receptors are modulated in varying ways. Therefore, CGRP or its receptors might be viable targets to manage secondary injuries following acute brain injury. In this review, we highlight the pathophysiology of the CGRP pathway and its relation to migraine pathogenesis. Using these same principles, we assess the existing preclinical data for CGRP and its role in acute brain injury. The findings are promising, and set the basis for further work, with specific focus on the therapeutic benefit of CGRP modulation following neurologic injury.

Calcitonin gene-related peptide-targeting drugs and Raynaud's phenomenon: a real-world potential safety signal from the WHO pharmacovigilance database

Background

Migraine is responsible for significant disability and societal burden. Recently, drugs targeting the calcitonin gene-related peptide (CGRP) pathway raised new hopes. CGRP, a potent vasodilator, plays a key role in the pathogenesis of migraine attacks. The deficiency of CGRP is involved in Raynaud’s phenomenon, which consists of abnormal vasoconstriction of the digits. We aimed to assess the potential association of Raynaud’s phenomenon with CGRP-targeting drugs, analyzing real-world data from the World Health Organization (VigiBase®).

Methods

We queried all reports of Raynaud’s phenomenon involving a CGRP-targeting drug. We sought disproportionate reporting of Raynaud’s phenomenon with these drugs. For this purpose, we relied on the calculation of the Information Component (IC). A positive lower end of the 95% confidence interval (CI) of the IC defines a statistically significant association. As migraine patients are prone to Raynaud’s phenomenon, we also calculated the IC of Raynaud’s phenomenon with CGRP-targeting drugs compared to 5HT1_B/D agonists (triptans), and beta-blockers used in the treatment of migraine.

Results

Overall, 99 reports of Raynaud’s phenomenon involving CGRP-targeting drugs have been yielded in VigiBase®. The most reported CGRP-targeting drug was erenumab, with 56 reports (56.6%). The median time to onset was 84 days. No fatality was notified, but one patient suffered from gangrene and extremity necrosis. As a whole, CGRP-targeting drugs were significantly associated with Raynaud’s phenomenon, with an IC of 3.3 (95%CI: 3.0–3.5). There was a disproportionate reporting of Raynaud’s phenomenon with CGRP-targeting drugs compared to triptans (IC 0.4; 95%CI: 0.1–0.6) and to beta-blockers (IC 0.5; 95%CI: 0.2–0.7) as well.

Conclusions

There is a significant disproportionality signal of Raynaud’s phenomenon with CGRP-targeting. This signal stands out when CGRP-targeting drugs are compared to other drugs used in patients with migraine. This study is limited by missing data in pharmacovigilance reports. CGRP-targeting drugs may be subject to Weber effect and reporting bias. Nonetheless, CGRP blockade might be the last straw that disrupts the physiological balance of vascular response in patients at-risk of Raynaud’s phenomenon. Pending further data regarding vascular safety of CGRP-targeting drugs, caution is warranted in these patients.

Pharmacological interventions for prophylaxis of vestibular migraine

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To assess the benefits and harms of pharmacological treatments used for prophylaxis of vestibular migraine.

Current Perspectives on the Impact of Chronic Migraine on Sleep Quality: A Literature Review

OBJECTIVE

Recent studies have shown that sleep problems occur in migraineurs and poor sleep causes chronification, but the mechanisms by which chronic migraine affects sleep quality are still unknown. This review aims to analyze commonly reported sleep disturbances in chronic migraine (CM) and determine the effect of CM on sleep quality.

MATERIALS AND METHODS

We conducted a comprehensive review of all published articles on CM and sleep quality from inception to March 2022 in the literature. Clinical trials, observational studies, and case series (≥20 cases) were included. Two reviewers and a supervisor reviewed the titles and abstracts of all search results with predefined inclusion and exclusion criteria. PubMed search for randomized controlled trials and open studies on CM and sleep quality reported in English between 1983 and 2022 was conducted using the keywords including chronic migraine, sleep, insomnia, sleep quality, polysomnography, and Pittsburgh Sleep Quality Index.

RESULTS

A total of 535 potentially relevant articles were found. A total of 455 articles and reviews, meta-analyses published in any language other than English, with other exclusion criteria, were excluded from the review. In the remaining articles, 36 clinical studies, reviewing sleep quality and its association with migraine, were identified and reviewed. Evidence from this review shows that poor sleep and migraine chronicity are intertwined with other accompanying comorbidities and dysregulation of circadian rhythm that innovative treatments promise to bring relief to both poor sleep as well as migraine.

CONCLUSION

Sleep disorders are common in CM and the association between migraine chronification and sleep quality is bidirectional. Comorbid conditions with accompanying frequent attacks in migraine may impair sleep quality. While the maladaptive pain process worsens sleep, poor sleep quality also negatively affects migraine pain. Sleep disturbance, which is affected by worsening migraine attacks, causes deterioration in the quality of life, loss of workforce, and economic burden.

Perampanel may represent an effective treatment for the prevention of migraine comorbid with epilepsy

INTRODUCTION

Migraine is a common comorbidity in patients with epilepsy. Considering the proven associations and the common pathophysiological features linking epilepsy and migraine, some anti-seizure medications (ASMs) have been considered as a treatment for both disorders. This study aimed at assessing both the effectiveness of perampanel (PER) on epileptic seizures and migraine attacks in patients with epilepsy and comorbid migraine, as well as the reduction in the monthly mean rate usage of rescue migraine medications.

METHODS

This observational, multi-centre study included adult patients with epilepsy and comorbid migraine who started PER to better control epileptic seizures and who were followed up for 12 months.

RESULTS

Thirty-one patients were included (mean age 40.13 ± 13.13 years; 67.0% female). At the 12-month follow-up visit, 27 patients were continuing PER concomitantly with 1 (45.2%) or 2 ASMs (54.8%). A significant reduction in epileptic seizures, migraine attacks, and the monthly use of rescue migraine medications between baseline and both 6- and 12-month follow-up visits was documented.

CONCLUSION

PER demonstrated good effectiveness in reducing both epileptic seizures and migraine attacks in patients with comorbid epilepsy and migraine. Future studies with possibly larger samples are needed to evaluate the efficacy of PER in migraine other than epilepsy.

Effect of antibody switch in non-responders to a CGRP receptor antibody treatment in migraine: A multi-center retrospective cohort study

BACKGROUND

Switching between antibody classes might be a treatment option in migraine patients who have not responded to one class of a CGRP-(receptor) monoclonal antibody (mAb), but there are no efficacy data so far. In this real-world analysis, we assessed the treatment response to a CGRP-mAb in patients that have previously failed the CGRP-receptor-mAb erenumab.

METHODS

We analyzed retrospective headache diary data of 78 patients with migraine who switched between CGRP-mAbs classes at four German headache centers either due to lack of efficacy or intolerable side effects. Among these, we identified 25 patients who did not respond to erenumab after three treatment cycles (defined as <30% reduction of monthly headache days) and had complete headache documentation at least one month before and during both treatments. We assessed the ≥30% responder rate at month three after switching from erenumab to a CGRP-mAb (galcanezumab or fremanezumab) (primary endpoint). Secondary endpoints included ≥50% responder rate, monthly headache days, and monthly days with acute medication use. In an exploratory subgroup analysis patients were stratified for daily and non-daily headache.

RESULTS

The switch from erenumab to a CGRP-mAb led to a ≥30% response in one-third (32%) of the patients after three treatment cycles. A ≥50% response was achieved in 12% of the patients. Monthly headache days were reduced in month three compared to baseline (20.8 ± 7.1 to 17.8 ± 9.1; p = 0.009). Stratified analysis revealed that no patient with daily headache (n = 9) responded to the treatment switch, while a 30% response was achieved by 50% of patients with non-daily headache (n = 16).

CONCLUSION

Our findings demonstrate that a relevant proportion of erenumab non-responders might benefit from a treatment switch to a CGRP-mAb. Switching seems to be a promising treatment option especially in migraine patients with non-daily headache.

Bio-chemical markers of chronic, non-infectious disease in the human tear film

The tear film is a thin, moist layer covering the ocular surface and is laden with proteins, peptides, lipids, mucins, electrolytes and cellular debris which function to maintain the healthy status of the ocular surface. In many cases of ocular or systemic disease, the integrity of this layer is changed and/or the balance of its constituents is disturbed. Since tears are easy and quick to collect and can be stored for long periods, they have the potential to be a valuable source of information relevant to many disease states. The purpose of this review is to collate information on the known biomarkers of systemic disease that have been identified in tears. The range of conditions covered includes diabetes mellitus, diabetic retinopathy, diabetic peripheral neuropathy, multiple sclerosis, Parkinson's disease, Alzheimer's disease, migraine, systemic sclerosis, cystic fibrosis, thyroid disorders and cancer.

The impact of CGRPergic monoclonal antibodies on prophylactic antimigraine therapy and potential adverse events

Migraine is a prevalent medical condition and the second most disabling neurological disorder. Regarding its pathophysiology, calcitonin gene-related peptide (CGRP) plays a key role, and, consequently, specific antimigraine pharmacotherapy has been designed to target this system. Hence, apart from the gepants, the recently developed monoclonal antibodies (mAbs) are a novel approach to treat this disorder. In this review we consider the current knowledge on the mechanisms of action, specificity, safety, and efficacy of the above mAbs as prophylactic antimigraine agents, and examine the possible adverse events that these agents may trigger. Antimigraine mAbs act as direct scavengers of CGRP (galcanezumab, fremanezumab, and eptinezumab) or against the CGRP receptor (erenumab). Due to their long half-lives, these molecules have revolutionized the prophylactic treatment of this neurovascular disorder. Moreover, because of their physicochemical properties, these agents are hepato-friendly and do not cross the blood-brain barrier (highlighting the relevance of peripheral mechanisms in migraine). Nevertheless, apart from potential cardiovascular side effects, the interaction with AMY₁ receptors and immunogenicity induced by autoantibodies against mAbs could be a concern for the safety of long-term treatment with these molecules.

A critical review of the neurovascular nature of migraine and the main mechanisms of action of prophylactic antimigraine medications

INTRODUCTION

Migraine involves neurovascular, functional, and anatomical alterations. Migraineurs experience an intense unilateral and pulsatile headache frequently accompanied with vomiting, nausea, photophobia, etc. Although there is no ideal preventive medication, frequency in migraine days may be partially decreased by some prophylactics, including antihypertensives, antidepressants, antiepileptics, and CGRPergic inhibitors. However, the mechanisms of action involved in antimigraine prophylaxis remain elusive.

AREAS COVERED

This review recaps some of the main neurovascular phenomena related to migraine and currently available preventive medications. Moreover, it discusses the major mechanisms of action of the recommended prophylactic medications.

EXPERT OPINION

In the last three years, migraine prophylaxis has evolved from nonspecific to specific antimigraine treatments. Overall, nonspecific treatments  mainly involve neural actions, whereas specific pharmacotherapy (represented by CGRP receptor antagonists and CGRPergic monoclonal antibodies) is predominantly mediated by neurovascular mechanisms that may include, among others: (i) reduction in the cortical spreading depression (CSD)-associated events; (ii) inhibition of pain sensitization; (iii) blockade of neurogenic inflammation; and/or (iv) increase in cranial vascular tone. Accordingly, the novel antimigraine prophylaxis promises to be more effective, devoid of significant adverse effects (unlike nonspecific treatments), and more beneficial for the quality of life of migraineurs.

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.

Benefit-Risk Assessment of Galcanezumab Versus Placebo for the Treatment of Episodic and Chronic Migraine Using the Metrics of Number Needed to Treat and Number Needed to Harm

INTRODUCTION

Subcutaneous galcanezumab was an effective, well-tolerated preventive treatment for adults with episodic (EM) or chronic migraine (CM) in 4 phase 3 randomized controlled trials: EVOLVE-1, EVOLVE-2, REGAIN, and CONQUER. Number needed to treat (NNT) and to harm (NNH) are metrics of effect size used to evaluate benefit-risk profiles. This study evaluated NNT, NNH, and benefit-risk profiles (measured as likelihood to be helped or harmed, LHH) of galcanezumab 120 mg versus placebo in patients with EM or CM.

METHODS

Primary efficacy outcomes were responses defined as ≥ 30%, ≥ 50%, and ≥ 75% reductions from baseline in number of monthly migraine headache days in patients with EM (EVOLVE-1; EVOLVE-2; CONQUER) and CM (REGAIN; CONQUER); corresponding NNTs to achieve respective responses; and corresponding NNHs for discontinuations due to adverse events (DCAEs) among the safety population. Secondary efficacy outcomes were responses for patients with ≥ 2 failed prior preventive treatments due to lack of efficacy and/or for tolerability reasons. All LHHs were based on ≥ 50% response and DCAEs.

RESULTS

During double-blind treatment periods with galcanezumab 120 mg, NNT to achieve ≥ 30% and ≥ 50% responses ranged from 4 to 10 and NNT to achieve ≥ 75% responses ranged from 5 to 23 in individual trials. NNH ranged from 93 to 1000, while LHH ranged from 18.6 to 104.6. NNTs were generally more robust among patients with EM than with CM; however, in patients with failure of ≥ 2 prior preventive treatments, NNTs to achieve ≥ 30% and ≥ 50% responses were similar between patients with CM and EM. NNHs were imputed as 1000 for both migraine types. Resulting LHHs were 178.8 (EM) and 127 (CM).

CONCLUSION

Across 4 trials, galcanezumab 120 mg demonstrated a favorable benefit-risk profile versus placebo, based on low NNTs to achieve response and high NNHs associated with DCAEs. LHH values consistently far exceeded 1.

TRIAL REGISTRATION NUMBERS

EVOLVE-1: ClinicalTrials.gov identifier, NCT02614183; EVOLVE-2: ClinicalTrials.gov identifier, NCT02614196; REGAIN: ClinicalTrials.gov identifier, NCT02614261; CONQUER: ClinicalTrials.gov identifier, NCT03559257.

Network meta-analysis on efficacy and safety of different anti-CGRP monoclonal antibody regimens for prophylaxis and treatment of episodic migraine

BACKGROUND

Currently, studies have shown that anti-CGRP monoclonal antibodies are effective drugs for the prophylaxis and treatment of episodic migraine. Therefore, for the first time, we classified and concluded 10 treatment regimens according to the different doses, drugs, routes of administration, and courses of treatment, so as to provide a reference for further clinical studies.

METHODS

We studied relevant randomized controlled trials (RCTs) published before August 2020 on PubMed, Embase, Ovid MEDLINE, Web of Science, and the Cochrane Central Register of Controlled Trials.

RESULTS

Eleven RCTs involving 6397 patients were included in our analysis. Network meta-analysis results suggested that in the comparison of the average migraine days per month, Erenumab  (140 mg), Galcanezumab (120 mg, 240 mg), Fremanezumab (225 mg, 675 mg) were superior to placebo, Erenumab(7 mg), and the difference was statistically significant; Fremanezumab (225 mg, 675 mg) was superior to Erenumab (21 mg, 70 mg), and the difference was statistically significant; in the comparison of average medication days of acute migraine-specific drug per month, Erenumab (70 mg, 140 mg), Galcanezumab (120 mg, 240 mg), Fremanezumab (225 mg, 675 mg) was superior to placebo, and Erenumab (140 mg) and Galcanezumab (120 mg, 240 mg) were superior to Erenumab (70 mg), and the difference was statistically significant; there was no statistically significant difference in the average migraine days in the last month or in the medication days of acute migraine-specific drug.

CONCLUSION

Fremanezumab (225 mg) and Galcanezumab (120 mg) may be the best clinical protocol after a comprehensive assessment.

Monoaminergic Receptors as Modulators of the Perivascular Sympathetic and Sensory CGRPergic Outflows

Blood pressure is a highly controlled cardiovascular parameter that normally guarantees an adequate blood supply to all body tissues. This parameter is mainly regulated by peripheral vascular resistance and is maintained by local mediators (i.e., autacoids), and by the nervous and endocrine systems. Regarding the nervous system, blood pressure can be modulated at the central level by regulating the autonomic output. However, at peripheral level, there exists a modulation by activation of prejunctional monoaminergic receptors in autonomic- or sensory-perivascular fibers. These modulatory mechanisms on resistance blood vessels exert an effect on the release of neuroactive substances from the autonomic or sensory fibers that modify blood pressure. Certainly, resistance blood vessels are innervated by perivascular: (i) autonomic sympathetic fibers (producing vasoconstriction mainly by noradrenaline release); and (ii) peptidergic sensory fibers [producing vasodilatation mainly by calcitonin gene-related peptide (CGRP) release]. In the last years, by using pithed rats, several monoaminergic mechanisms for controlling both the sympathetic and sensory perivascular outflows have been elucidated. Additionally, several studies have shown the functions of many monoaminergic auto-receptors and hetero-receptors expressed on perivascular fibers that modulate neurotransmitter release. On this basis, the present review: (i) summarizes the modulation of the peripheral vascular tone by adrenergic, serotoninergic, dopaminergic, and histaminergic receptors on perivascular autonomic (sympathetic) and sensory fibers, and (ii) highlights that these monoaminergic receptors are potential therapeutic targets for the development of novel medications to treat cardiovascular diseases (with some of them explored in clinical trials or already in clinical use).

Metabolic Aspects of Migraine: Association With Obesity and Diabetes Mellitus

Migraine is a disabling neurovascular disorder, characterized by moderate to severe unilateral headaches, nausea, photophobia, and/or phonophobia, with a higher prevalence in women than in men, which can drastically affect the quality of life of migraine patients. In addition, this chronic disorder is related with metabolic comorbidities associated with the patient's lifestyle, including obesity and diabetes mellitus (DM). Beyond the personal and socioeconomic impact caused by migraine, obesity and DM, it has been suggested that these metabolic disorders seem to be related to migraine since: (i) they are a risk factor for developing cardiovascular disorders or chronic diseases; (ii) they can be influenced by genetic and environmental risk factors; and (iii) while clinical and epidemiological studies suggest that obesity is a risk factor for migraine, DM (i.e., type 1 and type 2 DM) have been reported to be either a protective or a risk factor in migraine. On this basis, and given the high worldwide prevalence of migraine, obesity, and DM, this article provides a narrative review of the current literature related to the association between the etiology and pathophysiology of migraine and these metabolic disorders, considering lifestyle aspects, as well as the possible involvement of neurotransmitters, neuropeptides, and/or sex hormones. While a link between migraine and metabolic disorders has been suggested, many studies are contradictory and the mechanisms involved in this association are not yet sufficiently established. Therefore, further research should be focused on understanding the possible mechanisms involved.

Drug interactions and risks associated with the use of triptans, ditans and monoclonal antibodies in migraine

PURPOSE OF REVIEW

The aim of this study was to review current evidence concerning potential risks and interactions associated with concomitant use of drugs indicated for the abortive treatment of migraine, namely triptans and ditans, and more recently developed drugs used for the preventive treatment. The latter drug class encompasses monoclonal antibodies (mAbs), which target either calcitonin gene-related peptide (CGRP) or its receptor.

RECENT FINDINGS

To date, no pharmacokinetic interactions between these drug classes have been reported. However, patients who suffer from triptan- (or ditan-) induced medication overuse headache or those who are nonresponders to triptans might respond less effectively to mAbs. Caution is warranted when coadministrating these drugs in migraine patients with comorbid cardiovascular disease or with an increased cardiovascular risk profile.

SUMMARY

In this review, the main mechanisms of action of triptans, ditans and mAbs targeting CGRP or its receptor are summarized as well as the current evidence on their individual risks. Studies on risks and interactions in case of concomitant use of triptans, ditans and mAbs in migraine patients are relatively scarce. Therefore, these aspects have been considered from a theoretical and hypothetical point of view by taking both their overlapping target, CGRP, and contraindications into account.

Excitatory Effects of Calcitonin Gene-Related Peptide (CGRP) on Superficial Sp5C Neurons in Mouse Medullary Slices

The neuromodulator calcitonin gene-related peptide (CGRP) is known to facilitate nociceptive transmission in the superficial laminae of the spinal trigeminal nucleus caudalis (Sp5C). The central effects of CGRP in the Sp5C are very likely to contribute to the activation of central nociceptive pathways leading to attacks of severe headaches like migraine. To examine the potential impacts of CGRP on laminae I/II neurons at cellular and synaptic levels, we performed whole-cell patch-clamp recordings in juvenile mouse brainstem slices. First, we tested the effect of CGRP on cell excitability, focusing on neurons with tonically firing action potentials upon depolarizing current injection. CGRP (100 nM) enhanced tonic discharges together with membrane depolarization, an excitatory effect that was significantly reduced when the fast synaptic transmissions were pharmacologically blocked. However, CGRP at 500 nM was capable of exciting the functionally isolated cells, in a nifedipine-sensitive manner, indicating its direct effect on membrane intrinsic properties. In voltage-clamped cells, 100 nM CGRP effectively increased the frequency of excitatory synaptic inputs, suggesting its preferential presynaptic effect. Both CGRP-induced changes in cell excitability and synaptic drives were prevented by the CGRP receptor inhibitor BIBN 4096BS. Our data provide evidence that CGRP increases neuronal activity in Sp5C superficial laminae by dose-dependently promoting excitatory synaptic drive and directly enhancing cell intrinsic properties. We propose that the combination of such pre- and postsynaptic actions of CGRP might underlie its facilitation in nociceptive transmission in situations like migraine with elevated CGRP levels.

CGRP Receptor Antagonists and 5-HT1F Receptor Agonist in the Treatment of Migraine

Discovering that calcitonin-related peptide (CGRP) plays a key role in the complex pathophysiology of migraine has allowed us to make great strides in the development of new approaches for acute and preventive treatment. This evidence has led to the development of small molecules antagonist molecules of the CGRP receptor ("gepants") and of a new class of medications called "Ditans". This review presents the data from clinical trials reporting the efficacy, safety, and tolerability of the new drugs used in the treatment of migraines. Evidences show that therapeutic approaches targeted to CGRP have the potential to transform the clinical management of migraine, even though its appropriate place has yet to be determined with accuracy.

Rational Use of Lasmiditan for Acute Migraine Treatment in Adults: A Narrative Review

PURPOSE

This narrative review provides an update on the research that led to the development of ditans and lasmiditan for the acute treatment of migraine in adults and discusses the potential advantages and disadvantages of lasmiditan in clinical use.

METHODS

The electronic databases PubMed, Scopus, and ClinicalTrials.gov were searched from database inception through January 9, 2021, to identify relevant studies. Search results were assessed for their overall relevance to this review.

FINDINGS

Because part of the effect of the triptans is mediated by the serotonin 1F receptors, which are not present in the smooth muscle, a pure agonist of these receptors, lasmiditan, was developed. Lasmiditan is hypothesized to act on antinociceptive pathways and inhibit the calcitonin gene-related peptide release. Lasmiditan was approved by the US Food and Drug Administration in 2019 based on the results of 2 pivotal trials that found a significant difference from placebo in the percentage of patients who achieved freedom from pain and most bothersome symptom at 2 h. The main concern of lasmiditan derives from its central nervous system-related adverse effects, mainly dizziness and paraesthesia, probably attributable to its high blood brain barrier penetration. These central nervous system adverse effects impair driving performance for hours and might be suboptimal for individuals with migraine who want to quickly stop the migraine attack to resume their activities as soon as possible.

IMPLICATIONS

Despite the advantage of being beneficial in the acute treatment of migraine without vasocostrictive action, lasmiditan also presents limitations, in particular the central nervous system adverse effects. Moreover, head-to-head trials against triptans and gepants are indispensable to determine the better option for patients.

Onabotulinumtoxin A Improves Psychological Aspects in Chronic Migraine Patients

Background: Chronic migraine (CM) affects 5.4% of the Kuwaiti population. It is associated with significant headache-related disability, psychiatric comorbidity and reduced quality of life. The aim of this study is to assess the efficacy of Onabotulinumtoxin A on psychological aspects of chronic migraine patients. Methods: This prospective study over 36 months included chronic migraine patients in a tertiary headache center. Eligible patients met International Classification of Headache Disorders disorders-third edition, beta version (ICHD-III) revision criteria for chronic migraine. Patients with history of psychiatric or medical problems other than migraine disorders were excluded. Patients who received less than 4 injections cycles of Onabotulinumtoxin A were excluded. Identified patients received 155 units of Onabotulinumtoxin A quarterly according to the Phase III Research Evaluating Migraine Prophylaxis Therapy Trail (PREEMPT) protocol. Quality of life, the seven-item Generalized Anxiety Disorder (GAD-7) scores, the nine-item Patient Health Questionnaire (PHQ9), and the Pittsburgh Sleep Quality Index (PSQI) were collected before injection and at the end of the study. Mean comparison tests were performed using the independent sample t-test to assess the effects of Onabotulinumtoxin A on quality of life and comorbid symptoms of anxiety, depression, and quality of sleep. Results: The study identified 131 chronic migraine patients with a mean age of 44.92 years, mean disease duration of 12.20 years and a mean treatment sessions of 7.58. In their last visit, most of our sample showed improvement in quality of life (81%), GAD-7 (81%), PHQ9 (79%), and PSQ1 (76%). The mean score of patient satisfaction was 7.21. Onabotulinumtoxin A treatment for CM improved quality of life significantly (72.92 vs. 103.62; P < 0.0001). It was also associated with significant reduction in anxiety [GAD-7 (12.00 vs. 6.61; P < 0.0001)] and depression [PHQ-9 (17.91 vs. 12.52; P < 0.0001)] scores, as well as reduced difficulty in sleeping [PSQI (12.60 vs. 6.66; P < 0.0001)] at the last visit. Conclusion: Prophylactic Onabotulinumtoxin A treatment for CM was associated with significant improvement of quality of life, reduction in symptoms of anxiety and depression, as well as improved symptoms of poor sleep.

International Union of Basic and Clinical Pharmacology. CX. Classification of Receptors for 5-hydroxytryptamine; Pharmacology and Function

5-HT receptors expressed throughout the human body are targets for established therapeutics and various drugs in development. Their diversity of structure and function reflects the important role 5-HT receptors play in physiologic and pathophysiological processes. The present review offers a framework for the official receptor nomenclature and a detailed understanding of each of the 14 5-HT receptor subtypes, their roles in the systems of the body, and, where appropriate, the (potential) utility of therapeutics targeting these receptors. SIGNIFICANCE STATEMENT: This review provides a comprehensive account of the classification and function of 5-hydroxytryptamine receptors, including how they are targeted for therapeutic benefit.

Pharmacological treatment of migraine: CGRP and 5-HT beyond the triptans

Migraine is a highly disabling neurovascular disorder characterized by a severe headache (associated with nausea, photophobia and/or phonophobia), and trigeminovascular system activation involving the release of calcitonin-gene related peptide (CGRP). Novel anti-migraine drugs target CGRP signaling through either stimulation of 5-HT1F receptors on trigeminovascular nerves (resulting in inhibition of CGRP release) or direct blockade of CGRP or its receptor. Lasmiditan is a highly selective 5-HT1F receptor agonist and, unlike the triptans, is devoid of vasoconstrictive properties, allowing its use in patients with cardiovascular risk. Since lasmiditan can actively penetrate the blood-brain barrier, central therapeutic as well as side effects mediated by 5-HT1F receptor activation should be further investigated. Other novel anti-migraine drugs target CGRP signaling directly. This neuropeptide can be targeted by the monoclonal antibodies eptinezumab, fremanezumab and galcanezumab, or by CGRP-neutralizing L-aptamers called Spiegelmers. The CGRP receptor can be targeted by the monoclonal antibody erenumab, or by small-molecule antagonists called gepants. Currently, rimegepant and ubrogepant have been developed for acute migraine treatment, while atogepant is studied for migraine prophylaxis. Of these drugs targeting CGRP signaling directly, eptinezumab, erenumab, fremanezumab, galcanezumab, rimegepant and ubrogepant have been approved for clinical use, while atogepant is in the last stage before approval. Although all of these drugs seem highly promising for migraine treatment, their safety should be investigated in the long-term. Moreover, the exact mechanism(s) of action of these drugs need to be elucidated further, to increase both safety and efficacy and to increase the number of responders to the different treatments, so that all migraine patients can satisfactorily be treated.

Persistent post-traumatic headache: a migrainous loop or not? The clinical evidence

BACKGROUND

Headache is a common complication of traumatic brain injury. The International Headache Society defines post-traumatic headache as a secondary headache attributed to trauma or injury to the head that develops within seven days following trauma. Acute post-traumatic headache resolves after 3 months, but persistent post-traumatic headache usually lasts much longer and accounts for 4% of all secondary headache disorders.

MAIN BODY

The clinical features of post-traumatic headache after traumatic brain injury resemble various types of primary headaches and the most frequent are migraine-like or tension-type-like phenotypes. The neuroimaging studies that have compared persistent post-traumatic headache and migraine found different structural and functional brain changes, although migraine and post-traumatic headache may be clinically similar. Therapy of various clinical phenotypes of post-traumatic headache almost entirely mirrors the therapy of the corresponding primary headache and are currently based on expert opinion rather than scientific evidence. Pharmacologic therapies include both abortive and prophylactic agents with prophylaxis targeting comorbidities, especially impaired sleep and post-traumatic disorder. There are also effective options for non-pharmacologic therapy of post-traumatic headache, including cognitive-behavioral approaches, onabotulinum toxin injections, life-style considerations, etc. CONCLUSION: Notwithstanding some phenotypic similarities, persistent post-traumatic headache after traumatic brain injury, is considered a separate phenomenon from migraine but available data is inconclusive. High-quality studies are further required to investigate the pathophysiological mechanisms of this secondary headache, in order to identify new targets for treatment and to prevent disability.

Synthesis of isotopically labelled αCGRP8-37 and its lipidated analogue

α-Calcitonin gene related peptide (αCGRP) inhibitors are important medicinal targets due to their ability to produce antimigraine effects, thus, the discovery of long-acting αCGRP inhibitors is of significant interest. Herein we report the synthesis of an isotopically labelled version of the well-known CGRP receptor antagonist, αCGRP8-37 , as well as lipidated αCGRP8-37 with comparable antagonistic activity. These isotopically labelled peptides can be employed in assays to determine the metabolic stability of the lipidated αCGRP8-37 and compare this with the stability of known αCGRP8-37 .

Efficacy and Safety of Rimegepant for the Acute Treatment of Migraine: Evidence From Randomized Controlled Trials

Background

As one of the novel therapeutic drugs that targets Calcitonin gene-related peptide (CGRP), 75 mg rimegepant has been used for the acute management of migraine, which is one of the most common neurological diseases worldwide. Several clinical trials have been conducted to investigate the efficacy and safety of rimegepant for the acute management of migraine, but no systematic review of existing literature has been performed. We therefore performed a meta-analysis to investigate the efficacy and safety of rimegepant in treatment of patients with migraine.

Method

Pubmed, Embased, and Cochrane Library were searched from January 2001 to August 2019 for randomized controlled trials (RCTs). Four RCTs with 3,827 patients were finally included in our study.

Result

We pooled 3,827 patients from four RCTs, and the primary endpoints were freedom from pain, most bothersome symptom, and pain relief at 2 hr post dose. We found that 75 mg rimegepant led to significant freedom from pain (P < 0.001), pain relief (P < 0.001), and freedom from the most bothersome symptom (P < 0.001) at 2 hr post dose compared with the placebo. In addition, there was no statistically significant increase in adverse events compared with the placebo.

Conclusions

75 mg rimegepant had good efficacy and safety for acute treatment of migraine. Further studies are needed to compare the efficacy of rimegepant with traditional drugs for acute management of migraine.

Making Better Dose Decisions: Using Exposure-Response Modeling to Integrate Efficacy Outcome of Two Phase IIb Clinical Trials of Ubrogepant for Migraine Treatment

Ubrogepant (MK‐1602) is a novel, oral, calcitonin gene‐related peptide receptor antagonist in clinical development with positive phase III outcomes for acute treatment of migraine. This paper describes the population exposure‐response (E‐R) modeling and simulations, which were used to inform the phase III dose‐selection rationale, based on ~ 800 participants pooled across two phase IIb randomized dose‐finding clinical trials. The E‐R model describes the placebo and ubrogepant treatment effects based on migraine pain end points (2‐hour pain relief and 2‐hour pain freedom) at various dose levels. Sensitivity analyses were conducted to evaluate various assumptions of placebo response in light of the high placebo response observed in one phase II trial. A population pharmacokinetic model describing the effect of formulations was included in the E‐R simulation framework to assess potential dose implications of a formulation switch from phase II to phase III. Model‐based simulations predict that a dose of 25 mg or higher is likely to achieve significantly better efficacy than placebo with desirable efficacy levels. The understanding of E‐R helped support the dose selection for the phase III clinical trials.

Are Migraine With and Without Aura Really Different Entities?

Background: Migraine research is booming with the rapidly developing neuroimaging tools. Structural and functional alterations of the migrainous brain were detected with MRI. The outcome of a research study largely depends on the working hypothesis, on the chosen measurement approach and also on the subject selection. Against all evidence from the literature that migraine subtypes are different, most of the studies handle migraine with and without aura as one disease. Methods: Publications from PubMed database were searched for terms of "migraine with aura," "migraine without aura," "interictal," "MRI," "diffusion weighted MRI," "functional MRI," "compared to," "atrophy" alone and in combination. Conclusion: Only a few imaging studies compared the two subforms of the disease, migraine with aura, and without aura, directly. Functional imaging investigations largely agree that there is an increased activity/activation of the brain in migraine with aura as compared to migraine without aura. We propose that this might be the signature of cortical hyperexcitability. However, structural investigations are not equivocal. We propose that variable contribution of parallel, competing mechanisms of maladaptive plasticity and neurodegeneration might be the reason behind the variable results.

Evaluation of Galcanezumab for the Prevention of Episodic Migraine: The EVOLVE-1 Randomized Clinical Trial

Importance

Migraine is a disabling neurological disease characterized by severe headache attacks. Treatment options reduce migraine frequency for many patients, but adverse effects lead to discontinuation in many patients.

Objective

To demonstrate that galcanezumab is superior to placebo in the prevention of episodic migraine with or without aura.

Design, Setting, and Participants

The EVOLVE-1 (Evaluation of LY2951742 in the Prevention of Episodic Migraine 1) trial was a double-blind, randomized, placebo-controlled (January 11, 2016, to March 22, 2017) trial comparing galcanezumab (120 mg and 240 mg) vs placebo. Patients received treatments once monthly for 6 months (subcutaneous injection via prefilled syringe) and were followed up for 5 months after their last injection. It was a multicenter, clinic-based study involving 90 sites in North America. Participants in the study were adults (aged 18 to 65 years) with at least a 1-year history of migraine, 4 to 14 migraine headache days per month and a mean of at least 2 migraine attacks per month within the past 3 months, and were diagnosed prior to age 50 years. During the study, no other preventive medications were allowed. A total of 1671 patients were assessed; 809 did not meet study entry or baseline criteria, and 858 were included in the intent-to-treat population.

Interventions

Patients were randomized (2:1:1) to monthly placebo, galcanezumab, 120 mg, and galcanezumab, 240 mg.

Main Outcomes and Measures

The primary outcome was overall mean change from baseline in the number of monthly migraine headache days during the treatment period. Secondary measures included at least 50%, at least 75%, and 100% reduction in monthly migraine headache days, migraine headache days with acute medication use, and scores from the Migraine-Specific Quality of Life questionnaire, Patient Global Impression of Severity, and Migraine Disability Assessment. Treatment-emergent adverse events and serious adverse events were reported.

Results

Of the 1671 patients assessed, 858 (mean age, 40.7 years; 718 women [83.7%]) met study entry criteria and received at least 1 dose of investigational product. The primary objective was met for both galcanezumab doses; treatment with galcanezumab significantly reduced monthly migraine headache days (both P < .001) by 4.7 days (120 mg) and 4.6 days (240 mg) compared with placebo (2.8 days). All key secondary objectives were also significant after multiplicity adjustment. There were no meaningful differences between 120-mg and 240-mg doses of galcanezumab on measures of efficacy. Completion rate during treatment was high (81.9%; n = 718), and the incidence of discontinuation owing to adverse events was less than 5% across all treatment groups.

Conclusions and Relevance

Galcanezumab 120-mg and 240-mg monthly injections provided clinical benefits and improved functioning. The incidence rate of adverse events was low, demonstrating the favorable tolerability profile of galcanezumab.

Trial Registration

ClinicalTrials.gov Identifier: NCT02614183.

Functional Characterization of the Prejunctional Receptors Mediating the Inhibition by Ergotamine of the Rat Perivascular Sensory Peptidergic Drive

Calcitonin gene-related peptide (α-CGRP) released from perivascular sensory nerves induces decreases in diastolic blood pressure (DBP). Experimentally, this can be shown by spinal thoracic (T₉-T₁₂) electrical stimulation of these afferent fibers. Because ergotamine inhibits these neurogenic vascular responses and displays affinity for monoaminergic receptors that inhibit neurotransmitter release, we investigated whether this ergotamine-induced inhibition results from activation of serotonin 5-HT_1B/1D, dopamine D₂-like, and α₂-adrenergic receptors. Wistar rats were pithed and, under autonomic ganglion blockade, received intravenous infusions of methoxamine followed by ergotamine (0.1-3.1 μg kg^-1 min^-1). Thoracic T₉-T₁₂ electrical stimulation or an intravenous bolus of α-CGRP resulted in decreases in DBP. Ergotamine inhibited the electrically induced, but not α-CGRP-induced, responses. The vasodilator sensory inhibition by 3.1 μg of ergotamine kg^-1 min^-1 was resistant to simultaneous blockade of 5-HT_1B/1D, D₂-like, and α₂-adrenergic receptors upon addition of antagonists GR127935, haloperidol, and rauwolscine. Moreover, the inhibition by 0.31 μg of ergotamine kg^-1 min^-1 was unaltered by GR127935 and haloperidol, partly blocked by GR127935 and rauwolscine or rauwolscine and haloperidol, and abolished by GR127935, haloperidol, and rauwolscine. These findings imply that prejunctional 5-HT_1B/1D, D₂-like, and α₂-adrenergic receptors mediate the sensory inhibition induced by 0.31 μg of ergotamine kg^-1 min^-1, whereas larger doses may involve other receptors. Thus, ergotamine's ability to inhibit the perivascular sensory peptidergic drive may result in facilitation of its systemic vasoconstrictor properties.