Targeting CGRP: A New Era for Migraine Treatment

Potential analgesic effect of Foshousan oil-loaded chitosan-alginate nanoparticles on the treatment of migraine

Background: Migraine is a common neurovascular disorder with typical throbbing and unilateral headaches, causing a considerable healthcare burden on the global economy. This research aims to prepare chitosan-alginate (CS-AL) nanoparticles (NPs) containing Foshousan oil (FSSO) and investigate its potential therapeutic effects on the treatment of migraine. Methods: FSSO-loaded CS-AL NPs were prepared by using the single emulsion solvent evaporation method. Lipopolysaccharide (LPS)-stimulated BV-2 cells and nitroglycerin (NTG)-induced migraine mice were further used to explore anti-migraine activities and potential mechanisms of this botanical drug. Results: FSSO-loaded CS-AL NPs (212.1 ± 5.2 nm, 45.1 ± 6.2 mV) had a well-defined spherical shape with prolonged drug release and good storage within 4 weeks. FSSO and FSSO-loaded CS-AL NPs (5, 10, and 15 μg/mL) showed anti-inflammatory activities in LPS-treated BV-2 cells via reducing the levels of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and nitric oxide (NO), but elevating interleukin-10 (IL-10) expressions. Moreover, FSSO-loaded CS-AL NPs (52 and 104 mg/kg) raised pain thresholds against the hot stimulus and decreased acetic acid-induced writhing frequency and foot-licking duration in NTG-induced migraine mice. Compared with the model group, calcitonin gene-related peptide (CGRP) and NO levels were downregulated, but 5-hydroxytryptamine (5-HT) and endothelin (ET) levels were upregulated along with rebalanced ET/NO ratio, and vasomotor dysfunction was alleviated by promoting cerebral blood flow (CBF) in the FSSO-loaded CS-AL NPs (104 mg/kg) group. Conclusion: FSSO-loaded CS-AL NPs could attenuate migraine via inhibiting neuroinflammation in LPS-stimulated BV-2 cells and regulating vasoactive substances in NTG-induced migraine mice. These findings suggest that the FSS formula may be exploited as new phytotherapy for treating migraine.

Erenumab efficacy in migraine headache prophylaxis: A systematic review

OBJECTIVE

This systematic review aims to show the efficiency of Erenumab in the preventive therapy of episodic and chronic migraine, which is still under research.

BACKGROUND

Migraine is a chronic neurovascular disorder that causes disability and a social burden. There are various medications used for migraine prevention regimens, most of which have unwanted side effects and aren't often quite effective. Erenumab is a monoclonal antibody that targets calcitonin gene-related peptide receptors and was recently approved by the Food and Drug Administration for migraine prevention.

METHODS

For this systematic review, we searched through Scopus and PubMed databases using "Erenumab" or "AMG 334" and "migraine" as keywords, and all the studies from 2016 to March 18, 2022, were included. Original English articles assessing any outcomes referring to the efficacy of Erenumab in migraine headache treatment were included in this study.

RESULTS

We found 53 out of 605 papers eligible to be investigated. Erenumab in both dosages of 70 mg and 140 mg could decrease the mean of monthly migraine days and monthly acute migraine-specific medication days. Erenumab also has a higher rate of ≥ 50 %, ≥ 75 %, and 100 % reduction in monthly migraine days from the baseline in different regions. The efficacy of Erenumab was initiated in the first week of administration and sustained throughout and after treatment. Erenumab was also potent in the treatment of migraine with allodynia, aura, prior preventive therapy failure, medication overuse headache, and menstrual migraine. Erenumab also had favorable outcomes in combination therapy with other preventive drugs like Onabotulinumtoxin-A.

CONCLUSION

Erenumab had remarkable efficacy in the short and long-term treatment of episodic and chronic migraine, notably the patients with difficult-to-treat migraine headaches.

Treatment of resistant chronic migraine with anti-CGRP monoclonal antibodies: a systematic review

Background

Resistant chronic migraine is a highly disabling condition which is very difficult to treat. The majority of the treatments for migraine prophylaxis are nonspecific and present weak safety profiles, leading to low adherence and discontinuation. Currently, monoclonal antibodies (mAb) targeting the trigeminal sensory neuropeptide, calcitonin gene-related peptide (CGRP), are available for migraine prophylaxis being the first drugs developed specifically to target migraine pathogenesis. The main objective of the current work is to carry out a systematic review of randomised controlled trials that specifically analyse the effectivity and safety of anti-CGRP mAb, comparatively to placebo, in patients with resistant chronic migraine and possibly fill the literature gap or be a source of information to health professionals. Additionally the current knowledge on migraine, particularly resistant chronic migraine, was revisited and summarised.

Methods

Literature search was carried out on MEDLINE, Scopus, Science Direct and ClinicalTrials.gov database, from inception to December 2021. Articles were selected according to prespecified criteria of inclusion and exclusion. Efficacy and safety outcomes included were: change from baseline in monthly migraine days (MMD); ≥50% reduction of MMD values from baseline; change from baseline in monthly acute migraine-specific medication days (MAMD); Migraine-specific Quality of Life Questionnaire (MSQ); and registered adverse events. Additionally, we used the Cochrane risk of bias tool (RoB 2) to assess the risk of bias of the included studies.

Results

Four studies were included in this systematic review, involving 2811 resistant chronic migraine patients, 667 in a study using erenumab, 838 in a study using fremanezumab and 1306 in two studies using galcanezumab. When compared to placebo, all investigated anti-CGRP mAb and respective doses demonstrate effectiveness in decreasing MMD, reducing acute medication use and improving the MSQ scores, including, sometimes, reversion of chronic to episodic migraine (efficacy outcomes). Regarding the safety outcomes, the number and type of adverse events did not differ between anti-CGRP mAb-treated and placebo groups.

Conclusions

Anti-CGRP or anti-CGRP receptor monoclonal antibodies are a promising preventive migraine therapy which can be particularly useful for resistant chronic migraine patients.

VDR Gene Polymorphisms and Cluster Headache Susceptibility: Case-Control Study in a Southeastern European Caucasian Population

Cluster headache (CH) is a severe primary headache disorder with a genetic component, as indicated by family and twin studies. Diurnal and seasonal rhythmicity are key features of the disease and might be related to vitamin D, as low vitamin D levels have been observed in patients with cluster headache. In addition, the vitamin D receptor (VDR) occurs in brain areas and particularly in the hypothalamus. The aim of the present case-control study was to investigate the association of cluster headache susceptibility and clinical phenotypes with the VDR gene polymorphisms FokI, BsmI and TaqI in a Southeastern European Caucasian population. DNA was extracted from 131 unrelated CH patients and 282 non-headache controls and genotyped using real-time PCR (melting curve analysis). Linkage disequilibrium (LD) analysis confirmed that BsmI and TaqI, both located in the 3'UTR of the VDR gene, are in strong LD. Genotype and allele frequency distribution analysis of the VDR FokI, BsmI, and TaqI polymorphisms showed no statistically significant difference between cases and controls, whereas haplotype analysis indicated that the TAC haplotype might be associated with decreased cluster headache susceptibility. Intra-patient analysis according to diverse clinical phenotypes showed an association of the BsmI GG and TaqI TT genotypes with more frequent occurrence of CH attacks in this cohort. Therefore, a possible association was observed between VDR gene polymorphisms BsmI and TaqI or a linked locus and susceptibility for cluster headache development and altered clinical phenotypes in the Southeastern European Caucasian study population. Further large-scale replication studies are needed to validate these findings.

Pharmacological treatment of migraine: Drug classes, mechanisms of action, clinical trials and new treatments

Migraine is the sixth most prevalent disease globally, a major cause of disability, and it imposes an enormous personal and socioeconomic burden. Migraine treatment is often limited by insufficient therapy response, leading to the need for individually adjusted treatment approaches. In this review, we analyse historical and current pharmaceutical development approaches in acute and chronic migraine based on a comprehensive and systematic analysis of Food and Drug Administration (FDA)-approved drugs and those under investigation. The development of migraine therapeutics has significantly intensified during the last 3 years, as shown by our analysis of the trends of drug development between 1970 and 2020. The spectrum of drug targets has expanded considerably, which has been accompanied by an increase in the number of specialised clinical trials. This review highlights the mechanistic implications of FDA-approved and currently investigated drugs and discusses current and future therapeutic options based on identified drug classes of interest.

Monoclonal Antibodies Targeting CGRP: From Clinical Studies to Real-World Evidence-What Do We Know So Far?

Now more than ever is the time of monoclonal antibody use in neurology. In headaches, disease-specific and mechanism-based treatments existed only for symptomatic management of migraines (i.e., triptans), while the standard prophylactic anti-migraine treatments consist of non-specific and repurposed drugs that share limited safety profiles and high risk for interactions with other medications, resulting in rundown adherence rates. Recent advances in headache science have increased our understanding of the role of calcitonin gene relate peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) pathways in cephalic pain neurotransmission and peripheral or central sensitization, leading to the development of monoclonal antibodies (mAbs) or small molecules targeting these neuropeptides or their receptors. Large scale randomized clinical trials confirmed that inhibition of the CGRP system attenuates migraine, while the PACAP mediated nociception is still under scientific and clinical investigation. In this review, we provide the latest clinical evidence for the use of anti-CGRP in migraine prevention with emphasis on efficacy and safety outcomes from Phase III and real-world studies.

Migraine and Sleep-An Unexplained Association?

Migraine and sleep disorders are common chronic diseases in the general population, with significant negative social and economic impacts. The association between both of these phenomena has been observed by clinicians for years and is confirmed by many epidemiological studies. Despite this, the nature of this relationship is still not fully understood. In recent years, there has been rapid progress in understanding the common anatomical structures of and pathogenetic mechanism between sleep and migraine. Based on a literature review, the authors present the current view on this topic as well as ongoing research in this field, with reference to the key points of the biochemical and neurophysiological processes responsible for both these disorders. In the future, a better understanding of these mechanisms will significantly expand the range of treatment options.

Calcitonin Gene-Related Peptide Monoclonal Antibody Versus Botulinum Toxin for the Preventive Treatment of Chronic Migraine: Evidence From Indirect Treatment Comparison

Background: The previously approved botulinum toxin and nowadays promising calcitonin gene-related peptide (CGRP) monoclonal antibody have shown efficacy for preventing chronic migraine (CM). However, there is no direct evidence for their relative effectiveness and safety. In this study, we conducted an indirect treatment comparison to compare the efficacy and safety of CGRP monoclonal antibody with botulinum toxin for the preventive treatment of chronic migraine.

Methods: Up to August 31, 2020, we systematically searched PubMed, Embase, and Cochrane Library Central Register of Controlled Trials (Central). Weighted mean difference (WMD) and relative risk (RR) were used to evaluate clinical outcomes. Indirect treatment comparison (ITC) software was used to conduct indirect treatment comparison.

Results: Ten studies were pooled with 6,325 patients in our meta-analysis. Both botulinum toxin and CGRP monoclonal antibody demonstrated favorable efficacy in the change of migraine days, headache days, HIT-6 score, and 50% migraine responder rate compared with placebo. In indirect treatment comparison, CGRP monoclonal antibody was superior to botulinum toxin in the frequency of acute analgesics intake (WMD = −1.31, 95% CI: −3.394 to 0.774, p = 0.02113), the rate of treatment-related adverse events (AEs) (RR = 0.664, 95% CI: 0.469 to 0.939, p = 0.04047), and the rate of treatment-related serious adverse events (RR = 0.505, 95% CI: 0.005 to 46.98, p < 0.001).

Conclusion: For chronic migraine patients, CGRP monoclonal antibody was slightly better than botulinum toxin in terms of efficacy and safety. In the future, head-to-head trials would be better to evaluate the efficacy and safety between different medications in the prevention of chronic migraine.

Rimegepant: acute treatment for migraine headaches

Migraine headache treatment is quickly evolving. There have been three new acute migraine treatment options (i.e., lasmiditan, rimegepant, ubrogepant) and four new preventive migraine treatment options (i.e., erenumab, fremanezumab, galcanezumab, eptinezumab) released in the past 3 years. The new migraine treatments are focusing on pathways within the newly, better understood neurovascular hypothesis that further describes the pathophysiology of migraine headaches in more detail than before. The discovery of vasoactive peptides, such as calcitonin gene-related peptide, has led to the development of many of these migraine agents. Rimegepant is one of these newly approved agents for acute migraine treatment in adults with or without aura. Rimegepant has been found to decrease pain and symptoms associated with migraine attacks and is generally well-tolerated.

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.

High-flow oxygen and pro-serotonin agents for non-interventional treatment of post-dural-puncture headache

OBJECTIVE

Post dural puncture headache (PDPH) is a common complication in patients following diagnostic or therapeutic lumbar puncture, procedures requiring epidural access, and spinal surgery. Epidural blood patch (EBP), the gold standard for the treatment of this pathology requires training not provided to emergency physicians. In addition, the presence of concomitant pathology and abnormal laboratory values are contraindications to perform EBP. In presence of these limitations, we sought for a non-interventional management of PDPH utilizing high-flow oxygen and pro-serotonin agents. We reviewed the mechanism of action of this therapy METHODS: To illustrate our proposal, we report a series of twelve consecutive patients with PDPH treated with high-flow oxygen therapy at 12 L/min via a non-rebreathing mask and intravenous metoclopramide.

RESULTS

All patients were treated with this conservative therapy, no adverse reactions were observed. After the intervention, the headache resolved without further indications for PDPH.

CONCLUSION

Our series suggests that combining high-flow oxygen and pro-serotonin agents such metoclopramide in the ED might be a feasible option as effective as the invasive methods used in treating PDPH. This therapy appears to be efficient and to minimize risk, cost and side effects. It presents an easily accessible alternative that should be considered when PDPH is not a viable option.

Calcitonin gene-related peptide (CGRP)-targeted therapies as preventive and acute treatments for migraine-The monoclonal antibodies and gepants

Calcitonin Gene-Related Peptide (CGRP) plays a pivotal role in migraine pathophysiology. Two types of CGRP function-blocking modalities, monoclonal antibodies, and small molecules (gepants), have been developed to target the CGRP ligands and CGRP receptors. Four CGRP monoclonal antibodies have received FDA approval for the prevention of migraine: erenumab, fremanezumab, galcanezumab, and eptinezumab. Two gepants have been approved by the FDA for the acute treatment of migraine: ubrogepant and rimegepant. Multiple clinical trials of the CGRP monoclonal antibodies and gepants, and now some open-label long-term extension data, established their efficacy, safety, and tolerability. In this chapter, we summarize the major clinical trials, pharmacokinetic insights, safety and tolerability profiles, and real-world data (if available) of the CGRP monoclonal antibodies and gepants.

Mouse Models of Familial Hemiplegic Migraine for Studying Migraine Pathophysiology

Migraine, an extremely disabling neurological disorder, has a strong genetic component. Since monogenic mi-graines (resulting from mutations or changes in a single gene) may help researchers discover migraine pathophysiology, transgenic mice models harboring gene mutations identified in Familial Hemiplegic Migraine (FHM) patients have been gen-erated. Studies in these FHM mutant mice models have shed light on the mechanisms of migraine and may aid in the identifi-cation of novel targets for treatment. More specifically, the studies shed light on how gene mutations, hormones, and other factors impact the pathophysiology of migraine. The models may also be of relevance to researchers outside the field of mi-graine as some of their aspects are relevant to pain in general. Additionally, because of the comorbidities associated with mi-graine, they share similarities with the mutant mouse models of epilepsy, stroke, and perhaps depression. Here, we review the experimental data obtained from these mutant mice and focus on how they can be used to investigate the pathophysiology of migraine, including synaptic plasticity, neuroinflammation, metabolite alterations, and molecular and behavioral mecha-nisms of pain.

The Therapeutic Impact of New Migraine Discoveries

BACKGROUND

Migraine is one of the most disabling neurological conditions and associated with high socio-economic costs. Though certain aspects of the pathomechanism of migraine are still incompletely understood, the leading hypothesis implicates the role of the activation of the trigeminovascular system. Triptans are considered to be the current gold standard therapy for migraine attacks; however, their use in clinical practice is limited. Prophylactic treatment includes non-specific approaches for migraine prevention. All these support the need for future studies in order to develop innovative anti-migraine drugs.

OBJECTIVE

The present study is a review of the current literature regarding new therapeutic lines in migraine research.

METHODS

A systematic literature search in the database of PUBMED was conducted concerning therapeutic strategies in a migraine published until July 2017.

RESULTS

Ongoing clinical trials with 5-HT1F receptor agonists and glutamate receptor antagonists offer promising new aspects for acute migraine treatment. Monoclonal antibodies against CGRP and the CGRP receptor are revolutionary in preventive treatment; however, further long-term studies are needed to test their tolerability. Preclinical studies show positive results with PACAP- and kynurenic acid-related treatments. Other promising therapeutic strategies (such as those targeting TRPV1, substance P, NOS, or orexin) have failed to show efficacy in clinical trials.

CONCLUSION

Due to their side-effects, current therapeutic approaches are not suitable for all migraine patients. Especially frequent episodic and chronic migraine represents a therapeutic challenge for researchers. Clinical and preclinical studies are needed to untangle the pathophysiology of migraine in order to develop new and migraine-specific therapies.

Current and emerging evidence-based treatment options in chronic migraine: a narrative review

Background

Chronic migraine is a disabling condition that is currently underdiagnosed and undertreated. In this narrative review, we discuss the future of chronic migraine management in relation to recent progress in evidence-based pharmacological treatment.

Findings

Patients with chronic migraine require prophylactic therapy to reduce the frequency of migraine attacks, but the only currently available evidence-based prophylactic treatment options for chronic migraine are topiramate and onabotulinumtoxinA. Improved prophylactic therapy is needed to reduce the high burden of chronic migraine in Italy. Monoclonal antibodies that target the calcitonin gene-related peptide (CGRP) pathway of migraine pathogenesis have been specifically developed for the prophylactic treatment of chronic migraine. These anti-CGRP/R monoclonal antibodies have demonstrated good efficacy and excellent tolerability in phase II and III clinical trials, and offer new hope to patients who are currently not taking any prophylactic therapy or not benefitting from their current treatment.

Conclusions

Treatment of chronic migraine is a dynamic and rapidly advancing area of research. New developments in this field have the potential to improve the diagnosis and provide more individualised treatments for this condition. Establishing a culture of prevention is essential for reducing the personal, social and economic burden of chronic migraine.

In vitro affinity maturation of antibody against membrane-bound GPCR molecules

G protein-coupled receptors (GPCRs), also known as seven-transmembrane domain receptors, are among the most important targets against which many small molecule drugs have been developed. However, only two antibody drugs targeting GPCRs have been approved for clinical use although many antibody drugs against non-GPCR protein targets have been successfully developed for various disease indications. One of the challenges for developing anti-GPCR drugs is the high difficulty to perform affinity maturation due to their insolubility in aqueous solutions. To address this issue, CHO cell display libraries of single-chain variable fragments (scFvs) and full-length antibodies were maturated directly against vesicle probes prepared from CHO cells displaying the endothelin A receptor (ETaR) GPCR. The probe in the vesicle form ensures the physiological conformation and functional activity of the protein and avoids issues with membrane protein insolubility. The size of the vesicle had a clear effect on protein-ligand interaction; we used small-sized vesicles with low expression levels of GPCRs for the affinity maturation. Four rounds of affinity maturation combining vesicles as probes with the CHO cell display platform improved affinity by 13.58-fold for scFvs and 5.05-fold for full-length antibodies. We expect that this method will not only be used for the affinity maturation of antibodies against GPCRs but will also be used to mature antibodies for other types of proteins where the conformation/activity of which depends on the proper membrane environment.

The need for new acutely acting antimigraine drugs: moving safely outside acute medication overuse

Background

The treatment of migraine is impeded by several difficulties, among which insufficient headache relief, side effects, and risk for developing medication overuse headache (MOH). Thus, new acutely acting antimigraine drugs are currently being developed, among which the small molecule CGRP receptor antagonists, gepants, and the 5-HT_1F receptor agonist lasmiditan. Whether treatment with these drugs carries the same risk for developing MOH is currently unknown.

Main body

Pathophysiological studies on MOH in animal models have suggested that decreased 5-hydroxytryptamine (5-HT, serotonin) levels, increased calcitonin-gene related peptide (CGRP) expression and changes in 5-HT receptor expression (lower 5-HT_1B/D and higher 5-HT_2A expression) may be involved in MOH. The decreased 5-HT may increase cortical spreading depression frequency and induce central sensitization in the cerebral cortex and caudal nucleus of the trigeminal tract. Additionally, low concentrations of 5-HT, a feature often observed in MOH patients, could increase CGRP expression. This provides a possible link between the pathways of 5-HT and CGRP, targets of lasmiditan and gepants, respectively. Since lasmiditan is a 5-HT_1F receptor agonist and gepants are CGRP receptor antagonists, they could have different risks for developing MOH because of the different (over) compensation mechanisms following prolonged agonist versus antagonist treatment.

Conclusion

The acute treatment of migraine will certainly improve with the advent of two novel classes of drugs, i.e., the 5-HT_1F receptor agonists (lasmiditan) and the small molecule CGRP receptor antagonists (gepants). Data on the effects of 5-HT_1F receptor agonism in relation to MOH, as well as the effects of chronic CGRP receptor blockade, are awaited with interest.

Understanding CGRP and Cardiovascular Risk

Increasing knowledge about the role of calcitonin gene-related peptide (CGRP) in migraine pathophysiology has led to the development of antibodies against this peptide or its receptor. However, CGRP is widely expressed throughout the body, participating not only in pathophysiological conditions but also in several physiological processes and homeostatic responses during pathophysiological events. Therefore, in this chapter, the risks of long-term blockade of the CGRP pathway will be discussed, with focus on the cardiovascular system, as this peptide has been described to have a protective role during ischemic events, and migraine patients present a higher risk of stroke and myocardial infarction.

Basic Considerations for the Use of Monoclonal Antibodies in Migraine

BACKGROUND

Migraine impacts more than 36 million people in the United States and 1 billion people worldwide. Despite the increasing availability of acute and preventive therapies, there is still tremendous unmet need. Potential treatments in development include monoclonal antibodies (mAbs). Appropriate use of these “biologic” treatments will necessitate an understanding of the aspects that distinguish them from traditional medications.

AIM

Many drug classes are prescribed for migraine treatment, but all have limitations. Recently, calcitonin gene-related peptide (CGRP) activity has shown a significant promise as a target for preventive therapy. In this review, we provide an overview of the potential role of CGRP mAbs in migraine, with a focus on their design, pharmacokinetics, safety, and immunogenicity.

CONCLUSIONS

The CGRP mAbs are an innovative new therapy for migraine and address the need for effective and tolerable preventive options. MAbs, including those that target CGRP or its receptor, bind to a target with high specificity and affinity and lead to few off-target adverse effects, although mechanism-based adverse reactions may occur. Unlike other therapeutic antibodies used to treat neurologic disease, CGRP mAbs do not have a target within the immune system and have been designed to avoid altering the immune system. The safety and efficacy of mAbs against CGRP or its receptors are being investigated in clinical development programs, and the first of these therapies has received regulatory approval in the United States.

Fremanezumab for preventive treatment of migraine: Functional status on headache-free days

Objective

To evaluate the effect of fremanezumab on the functional status on headache-free days in phase 2 episodic migraine (EM) and chronic migraine (CM) studies.

Methods

Functional status data were collected prospectively via the electronic headache diary on all headache-free days by patients answering questions regarding work/school/household chore performance, speed of work completion, concentration, and feeling of fatigue. Individuals with EM receiving monthly doses of fremanezumab 225 mg (n = 96) or 675 mg (n = 97) or placebo (n = 104) were compared. Individuals with CM receiving fremanezumab 675 mg followed by monthly 225 mg (n = 88) and 900 mg (n = 86) were also independently compared to those receiving placebo (n = 89).

Results

In patients with EM, compared to patients receiving placebo, those receiving fremanezumab experienced an increased number of headache-free days with normal function in work/school/household chore performance and concentration/mental fatigue measures compared to their baseline over the entire treatment period (all p < 0.005). An increased number of headache-free days with normal functional performance for some measures was also found in the CM group in those treated with fremanezumab.

Conclusion

There was an increased number of headache-free days with normal functional performance on all measures for the patients with EM and some measures for patients with CM in the fremanezumab-treated groups. Further research is required to confirm these findings in a prospective study and to clarify the underlying mechanism(s).

ClinicalTrials.gov identifier:

NCT02025556 and NCT02021773.

Classification of evidence

This study provides Class II evidence that for patients with migraine, fremanezumab increases normal functional performance on headache-free days.

Skin neurogenic inflammation

The epidermis closely interacts with nerve endings, and both epidermis and nerves produce substances for mutual sustenance. Neuropeptides, like substance P (SP) and calcitonin gene-related protein (CGRP), are produced by sensory nerves in the dermis; they induce mast cells to release vasoactive amines that facilitate infiltration of neutrophils and T cells. Some receptors are more important than others in the generation of itch. The Mas-related G protein-coupled receptors (Mrgpr) family as well as transient receptor potential ankyrin 1 (TRPA1) and protease activated receptor 2(Par2) have important roles in itch and inflammation. The activation of MrgprX1 degranulates mast cells to communicate with sensory nerve and cutaneous cells for developing neurogenic inflammation. Mrgprs and transient receptor potential vanilloid 4 (TRPV4) are crucial for the generation of skin diseases like rosacea, while SP, CGRP, somatostatin, β-endorphin, vasoactive intestinal peptide (VIP), and pituitary adenylate cyclase-activating polypeptide (PACAP) can modulate the immune system during psoriasis development. The increased level of SP, in atopic dermatitis, induces the release of interferon (IFN)-γ, interleukin (IL)-4, tumor necrosis factor (TNF)-α, and IL-10 from the peripheral blood mononuclear leukocytes. We are finally starting to understand the intricate connections between the skin neurons and resident skin cells and how their interaction can be key to controlling inflammation and from there the pathogenesis of diseases like atopic dermatitis, psoriasis, and rosacea.

The Evidence for the Role of Nutraceuticals in the Management of Pediatric Migraine: a Review

PURPOSE OF REVIEW

Nutraceuticals are a form of complementary and alternative medicine that is commonly used by children and adolescents with migraine. In this review, observational studies, randomized controlled trials, systematic reviews, and meta-analyses on the efficacy and safety of single compound nutraceuticals for the management of migraine in children and adolescents were identified through a literature search of MEDLINE, Embase, and EBM Reviews-Cochrane Central Register of Controlled Trials.

RECENT FINDINGS

Twenty-one studies were reviewed, of which 11 were observational studies, 7 were randomized controlled trials, and 3 were systematic reviews. Six different nutraceuticals were included in the review: vitamin D, riboflavin, coenzyme Q10, magnesium, butterbur, and polyunsaturated fatty acids. All but three of the studies assessed the role of nutraceuticals in migraine prevention, while three studies evaluated the role of intravenous magnesium for acute migraine management. Overall, the quality and size of the studies were limited. Due to low quality evidence and limited studies, no definite conclusions can be drawn on the efficacy of nutraceuticals for the treatment of pediatric migraine. Future studies are warranted in order to establish evidence upon which to define the role of nutraceuticals in this patient population.

Migraine

Migraine is a chronic paroxysmal neurological disorder characterised by multiphase attacks of head pain and a myriad of neurological symptoms. The underlying genetic and biological underpinnings and neural networks involved are coming sharply into focus. This progress in the fundamental understanding of migraine has led to novel, mechanism-based and disease-specific therapeutics. In this Seminar, the clinical features and neurobiology of migraine are reviewed, evidence to support available treatment options is provided, and emerging drug, device, and biological therapies are discussed.

Amylin

Amylin is a 37 amino acid peptide hormone that is closely related to calcitonin gene-related peptide (CGRP). Amylin and CGRP share a receptor and are reported to have several similar biological actions. Given the important role of CGRP in migraine and intense efforts to develop drugs against this target, it is important to consider potential areas of overlap between the amylin and CGRP systems. This short review provides a brief introduction to amylin biology, the use of an amylin analog to treat diabetes, and consideration of whether amylin could have any role in headache disorders. Finally, this review informs readers about the AMY₁ (amylin subtype 1) receptor, which is a dual receptor for amylin and CGRP and potentially plays a role in the bioactivity of both of these peptides.

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).

CGRP, a target for preventive therapy in migraine and cluster headache: Systematic review of clinical data

Introduction

Migraine and cluster headache are challenging to manage, with no tailored preventive medications available. Targeting the calcitonin gene-related peptide (CGRP) pathway to treat these headaches may be the first focused therapeutic option to date, with the potential for promising efficacy.

Methods

We systematically searched PubMed and clinicaltrials.gov for randomized controlled trials investigating the preventive potential of monoclonal antibodies against the CGRP pathway in the treatment of migraine and cluster headache.

Results

The literature search returned a total of 136 records, of which 32 were eligible for review.

Discussion

Clinical data from phase II and III trials of the four monoclonal antibodies targeting the CGRP pathway: Eptinezumab, erenumab, fremanezumab, and galcanezumab, collectively show a positive effect in the preventive treatment of episodic and chronic migraine. Multiple phase II and III trials are under way to further determine the efficacy and safety of this new drug class. It may be particularly important to assess the cardiovascular effects of long-term CGRP blockade. Phase III trials are also currently in progress for the preventive treatment of cluster headache.

Conclusion

Efficacy of anti-CGRP monoclonal antibodies spells a promising future for the many patients suffering from migraine, and possibly also for the smaller but severely-affected population with cluster headache.

[Headache immunology]

The overview is dedicated to the neuroimmunological mechanisms of headache development and chronification. Based on the analyzed data, the authors determined the relationship between immunological parameters and duration, intensity and other characteristics of this disease. These findings confirm that immunocompetent cells can be used as headache biomarkers and predictors of treatment efficacy. Questions about the role of separate parts of the immune system in the development and maintenance of a headache require further research. Studies of humoral immunity appeared to be very promising.

Acupuncture modulates the abnormal brainstem activity in migraine without aura patients

Migraine is a common neurological disease with a high prevalence and unsatisfactory treatment options. The specific pathophysiological mechanisms of migraine remain unclear, which restricts the development of effective treatments for this prevalent disorder. The aims of this study were to 1) compare the spontaneous brain activity differences between Migraine without Aura (MwoA) patients and healthy controls (HCs), using amplitude of low-frequency fluctuations (ALFF) calculation method, and 2) explore how an effective treatment (verum acupuncture) could modulate the ALFF of MwoA patients. One hundred MwoA patients and forty-six matched HCs were recruited. Patients were randomized to four weeks' verum acupuncture, sham acupuncture, and waiting list groups. Patients had resting state BOLD-fMRI scan before and after treatment, while HCs only had resting state BOLD-fMRI scan at baseline. Headache intensity, headache frequency, self-rating anxiety and self-rating depression were used for clinical efficacy evaluation. Compared with HCs, MwoA patients showed increased ALFF in posterior insula and putamen/caudate, and reduced ALFF in rostral ventromedial medulla (RVM)/trigeminocervical complex (TCC). After longitudinal verum acupuncture treatment, the decreased ALFF of the RVM/TCC was normalized in migraine patients. Verum acupuncture and sham acupuncture have different modulation effects on ALFF of RVM/TCC in migraine patients. Our results suggest that impairment of the homeostasis of the trigeminovascular nociceptive pathway is involved in the neural pathophysiology of migraines. Effective treatments, such as verum acupuncture, could help to restore this imbalance.

Spotlight on Anti-CGRP Monoclonal Antibodies in Migraine: The Clinical Evidence to Date

Migraine, a common neurovascular brain disorder, represents a severe and widespread health problem; along with medication‐induced (medication‐overuse) headache, it is the third‐leading cause of disability worldwide. Currently, its therapeutic management remains unsatisfactory for several reasons; up to 40% of migraineurs are eligible for prophylactic treatment, but there are issues of efficacy, safety, and adherence. In recent years the evidence on the role of calcitonin gene‐related peptide (CGRP) in migraine pathophysiology has been consolidated, so new and promising treatments for migraine pain and its possible prevention have been developed. The following review reports the results of the clinical trials conducted so far with each of the new monoclonal antibodies targeting CGRP or its receptor, with particular reference to safety, tolerance, and efficacy in migraine prevention. Moreover, the pharmacological characterization and further developments of each monoclonal antibody are reported, based on current knowledge.

Analgesia effect of baicalein against NTG-induced migraine in rats

BACKGROUND

Migraine is a complex nervous system disease characterized by typical throbbing and unilateral headache, which causes severe healthy and social issues worldwide. The purpose of this study was to investigate the effect of baicalein (BAI) on the treatment of migraine.

MATERIAL AND METHODS

Twenty-four rats were randomly divided equally into four groups, including a blank group, model group, positive group (ibuprofen tablets 82mg/kg), and BAI group (60mg/kg). All rats were intragastrically treated with the corresponding treatment for 10 consecutive days, and they were subcutaneously injected with NTG (10mg/kg) 1h after the last treatment, except in the blank group. After model establishment, the behaviors of all rats, including scratching head and shaking body were observed continuously for 100min. Four hours after NTG treatment, all rats were anaesthetized and the blood was collected. Thereafter, nitric oxide (NO) in plasma was determined by colorimetric method, the level of calcitonin gene-related peptide (CGRP) and endothelin (ET) were detected by radioimmunoassay method. In addition, immunohistochemistry was applied to detect c-Fos neuronal activity in trigeminal nucleus caudalis (TNC).

RESULTS

Behavioral research showed that BAI administration alleviated the hyperalgesia in migraine rats. Compared with the model group, the levels of NO and CGRP in BAI administration groups were markedly decreased (p<0.01), and the levels of ET was significantly increased (p<0.01). Meanwhile, immunohistochemistry results showed that NTG treatment significantly activated c-Fos neurons while BAI treatment inhibited the expression of c-Fos.

CONCLUSIONS

BAI could alleviate the migraine-like headache induced by NTG, which is related to the regulation of vasoactive substances. These findings may contribute to the further study of BAI as a potential drug for migraine pharmacotherapy.

CGRP and its receptors

The calcitonin gene-related peptide (CGRP) neuropeptide system is an important but still evolving target for migraine. A fundamental consideration for all of the current drugs in clinical trials and for ongoing development in this area is the identity, expression pattern, and function of CGRP receptors because this knowledge informs safety and efficacy considerations. In recent years, only the calcitonin receptor-like receptor/receptor activity-modifying protein 1 (RAMP1) complex, known as the CGRP receptor, has generally been considered relevant. However, CGRP is capable of activating multiple receptors and could have more than one endogenous receptor. The recent identification of the CGRP-responsive calcitonin receptor/RAMP1 complex (AMY₁ receptor - amylin subtype 1 receptor) in the trigeminovascular system warrants a deeper consideration of the molecular identity of CGRP receptor(s) involved in the pathophysiology, and thus potential treatment of migraine. This perspective considers some of the issues and implications.

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.

Advances in the understanding of cluster headache

INTRODUCTION

Cluster headache is the worst primary headache form; it occurs in paroxysmal excruciatingly severe unilateral head pain attacks usually grouped in cluster periods. The familial occurrence of the disease indicates a genetic component but a gene abnormality is yet to be disclosed. Activation of trigeminal afferents and cranial parasympathetic efferents, the so-called trigemino-parasympathetic reflex, can explain pain and accompanying oculo-facial autonomic phenomena. In particular, pain in cluster headache is attributed, at least in part, to the increased CGRP plasma levels released by activated trigeminal system. Posterior hypothalamus was hypothesized to be the cluster generator activating the trigemino-parasympathetic reflex. Efficacy of monoclonal antibodies against CRGP is under investigation in randomized clinical trials. Areas covered: This paper will focus on main findings contributing to consider cluster headache as a neurovascular disorder with an origin from within the brain. Expert commentary: Accumulated evidence with hypothalamic stimulation in cluster headache patients indicate that posterior hypothalamus terminates rather than triggers the attacks. More extensive studies on the genetics of cluster headache are necessary to disclose anomalies behind the increased familial risk of the disease. Results from ongoing clinical trials in cluster headache sufferers using monoclonal antibodies against CGRP will open soon a new era.

Animal models of monogenic migraine

Migraine is a highly prevalent and disabling neurological disorder with a strong genetic component. Rare monogenic forms of migraine, or syndromes in which migraine frequently occurs, help scientists to unravel pathogenetic mechanisms of migraine and its comorbidities. Transgenic mouse models for rare monogenic mutations causing familial hemiplegic migraine (FHM), cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and familial advanced sleep-phase syndrome (FASPS), have been created. Here, we review the current state of research using these mutant mice. We also discuss how currently available experimental approaches, including epigenetic studies, biomolecular analysis and optogenetic technologies, can be used for characterization of migraine genes to further unravel the functional and molecular pathways involved in migraine.