Calcitonin Gene-Related Peptide (CGRP)-Targeted Monoclonal Antibodies and Antagonists in Migraine: Current Evidence and Rationale

Characterisation of periorbital mechanical allodynia in the reserpine-induced fibromyalgia model in mice: The role of the Schwann cell TRPA1/NOX1 signalling pathway

Fibromyalgia (FM) is a complex and multifaceted condition characterized by a range of clinical symptoms, including widespread pain and a strong association with migraine headaches. Recent findings have underscored the role of oxidative stress and transient receptor potential ankyrin 1 (TRPA1) channel in migraine and FM. However, the precise mechanisms underlying the comorbidity between migraine and FM are unclear. Periorbital mechanical allodynia (PMA), which recapitulates one of the major symptoms of migraine, and the feed-forward mechanism driven by reactive oxygen species and TRPA1, were investigated in a reserpine-induced FM model in C57BL/6J mice, employing pharmacological interventions and genetic approaches. Reserpine-treated mice developed PMA (which was alleviated by antimigraine drugs) and increased endoneurial macrophages and oxidative stress markers in the trigeminal nerve tissues (neuroinflammation). These responses were absent upon macrophage depletion and by pharmacological inhibition or global genetic deletion of the TRPA1 channel. Furthermore, selective silencing of TRPA1 in Schwann cells attenuated both reserpine-induced PMA and neuroinflammation, while selective silencing of TRPA1 in sensory neurons reduced PMA but not neuroinflammation. In reserpine-treated mice, Schwann cell TRPA1 promoted NADPH oxidase 1-mediated reactive oxygen species generation and macrophage density increase in the mouse trigeminal nerve, which sustains PMA. Targeting TRPA1 channels in Schwann cells could offer a novel therapeutic strategy for FM-related headaches.

Review: An Update on CGRP Monoclonal Antibodies for the Preventive Treatment of Episodic Migraine

PURPOSE OF REVIEW

CGRP targeting therapies have revolutionized the migraine preventive space, introducing novel migraine-specific therapies to improve headache care. Four monoclonal antibodies (mAbs) are approved for use in prevention of episodic migraines. Erenumab (AMG334), fremanezumab (TEV48125), and galcanezumab (LY2951742) are monthly subcutaneous injections, while eptinezumab (ALD403) provides an intravenous infusion option. This review aims to examine the clinical evidence for the safety and efficacy of CGRP-targeted mAbs in the prevention of episodic migraines with a focus on recent studies (2023-2024).

RECENT FINDINGS

Long-term studies reveal ongoing safety and efficacy in recent literature for all 4 monoclonal antibodies. These investigations have built evidence for earlier access to CGRP treatment as they increase quality of life and reduce monthly migraine days while being better tolerated than non-specific migraine preventative therapies. These studies support the recent 2024 AHS consensus statement recommending CGRP monoclonal antibodies be considered as first-line preventive treatment in episodic migraine.

An overview of the current and emerging treatment options for vestibular migraine

INTRODUCTION

Vestibular migraine is a relatively common syndrome characterized by the occurrence of vertigo and other vestibular symptoms, frequently -but not always- accompanied by migraine symptoms, such as headache, photophobia, and phonophobia.

AREAS COVERED

The authors review the acute or abortive treatment during an attack and prophylactic treatment of vestibular migraines, including pharmacological and non-pharmacological options.

EXPERT OPINION

Since its recognition as an independent clinical entity is recent, studies concerning its different treatment alternatives are still scarce, and the level of evidence of published studies is generally low. For acute treatment, although available data are conflicting, triptans are usually tried first. Neurostimulating devices can also be considered for acute treatment of vestibular migraine. Regarding the preventive treatment of vestibular migraine, based on the results of two randomized clinical trials and its pharmacological properties, flunarizine should be considered as the first treatment option. Second-line preventive treatments encompass propranolol, topiramate, venlafaxine, and valproic acid. Among non-pharmacological options, vestibular rehabilitation seems to be a sound prophylactic treatment option.

Safety and tolerability of ubrogepant for the acute treatment of migraine in participants taking atogepant for the preventive treatment of episodic migraine: Results from the TANDEM study

OBJECTIVE

To evaluate the safety and tolerability of ubrogepant for the acute treatment of migraine in participants taking atogepant for the preventive treatment of episodic migraine (EM).

BACKGROUND

Atogepant is an oral calcitonin gene-related peptide (CGRP) receptor antagonist approved for the preventive treatment of migraine in adults and ubrogepant is an oral CGRP receptor antagonist approved for the acute treatment of migraine in adults, with or without aura. The safety and tolerability of the concomitant use of ubrogepant and atogepant have not been previously evaluated in a clinical setting.

METHODS

The TANDEM study, a phase 4, two-period, multicenter, open-label study conducted in the United States, enrolled adults with migraine, with or without aura, and <15 headache days/month. In Treatment Period 1, participants took atogepant 60 mg once daily (QD) for 12 weeks and their own non-gepant acute headache medication for breakthrough migraine attacks. In Treatment Period 2, participants continued taking atogepant 60 mg QD and ubrogepant 100 mg was taken as needed (PRN) for the treatment of breakthrough migraine attacks (up to eight per 4-week interval) for 12 weeks. In Treatment Period 2, an optional second ubrogepant dose or the participant's own acute medication could be used to rescue headaches that did not resolve within 2-24 h post initial ubrogepant dose. The primary objective evaluated the safety and tolerability of the concomitant use of ubrogepant and atogepant.

RESULTS

Of 263 participants enrolled, 262 were treated in Treatment Period 1 (Safety Population 1) and 218 continued and were treated in Treatment Period 2 (Safety Population 2). The mean (standard deviation) number of ubrogepant use days in Treatment Period 2 was 6.6 (5.03) over the 12 weeks. In Treatment Periods 1 and 2, 49.6% and 43.1% of participants experienced a treatment-emergent adverse event (TEAE), respectively. The most common TEAEs (≥5%) in Treatment Period 1 and Treatment Period 2 were COVID-19 (8.4%, 3.2%), fatigue (6.5%, 1.4%), nausea (6.1%, 0.9%), decreased appetite (5.7%, 0.9%), and constipation (5.3%, 0.9%). In Treatment Period 2, no increase in the incidence and types of TEAEs in relation to the number of ubrogepant use days or doses taken were identified. During the whole treatment period, 9.9% of participants discontinued atogepant or ubrogepant treatment due to TEAEs. There was one serious TEAE in Treatment Period 1 (ureterolithiasis) and one in Treatment Period 2 (cervical myelopathy), and both were considered not related to study treatment by the study investigators.

CONCLUSION

The use of atogepant 60 mg QD for the preventive treatment of EM and ubrogepant 100 mg PRN for the acute treatment of migraine over the 12-week open-label concomitant use treatment period was safe and well tolerated. The overall safety results were consistent with the known safety profiles of atogepant and ubrogepant when used alone and no new safety signals were identified.

Safety and Efficacy of Atogepant for the Preventive Treatment of Migraines in Adults: A Systematic Review and Meta-Analysis

Background: Migraine is a common neurological condition marked by unilateral recurrent pulsating headaches, often associated with systemic signs and symptoms. Recently, calcitonin gene-related peptide (CGRP) antagonists, including atogepant, an oral CGRP receptor antagonist, have emerged as effective and safe treatments. The current study sought to assess the efficacy and safety of atogepant for preventing episodic migraines in adults. Methods: A comprehensive search, following PRISMA guidelines, was conducted using PubMed, Web of Science, and Cochrane Library to identify randomized, double-blind, placebo-controlled trials published up to June 2024. Results: The studies included adult participants with episodic migraine treated with atogepant. The primary outcomes assessed were changes in mean monthly migraine days (MMDs) and monthly headache days (MHDs) over 12 weeks. Secondary outcomes included reduction in acute medication use, 50% responder rates, and adverse events. A meta-analysis using a random-effects model was performed to evaluate efficacy and safety. Six trials with 4569 participants were included. Atogepant significantly reduced mean monthly migraine days (MMDs) and monthly headache days (MHDs) compared to placebo at all doses (10 mg, 30 mg, 60 mg), with the 60 mg dose showing the greatest reduction (mean difference: -1.48 days, p < 0.001). Significant reductions in acute medication use and improved 50% responder rates were also observed for all doses. The safety profile of atogepant was favorable, with common adverse events being mild to moderate, such as constipation and nausea. There were no significant differences in serious adverse events between the atogepant and placebo groups. Conclusions: Atogepant is an effective and well-tolerated option for preventing episodic migraines, showing significant reductions in migraine frequency and acute medication use. However, further studies are necessary to assess its long-term safety and efficacy, especially at higher doses, and to investigate its potential role in personalized treatment strategies for migraine prevention.

Debunking myths in headache diagnosis for the pain practitioner

With headache being one of the most common chief complaints, it is essential for pain practitioners to interpret and differentiate a variety of headache characteristics to accurately diagnose and treat specific headache disorders. Certain misconceptions often lead to misdiagnosis. This article presents and discusses six myths about several common headache disorders (migraine, tension-type headache, cluster headache, cervicogenic headache, sinus headache, and occipital neuralgia) often encountered in clinical practice. The discussion is based primarily on the International Classification of Headache Disorders, 3rd edition and the latest studies. Recognizing and understanding the intricacies behind key headache diagnoses will help providers devise appropriate plans to better care for their patients.

Drug effects on neuropeptides and their receptors: Big hopes but moderate success in the treatment of chronic pain

Neuropeptides, including tachykinins, CGRP, and somatostatin, are localized in a peptidergic subgroup of nociceptive primary afferent neurons. Tachykinins and CGRP are pronociceptive, somatostatin is an antinociceptive mediator. Intensive drug research has been performed to develop tachykinin and CGRP antagonists, and somatostatin agonists as analgesics. CGRP receptor antagonists are efficacious and well-tolerated drugs in migraine. Monoclonal antibodies against CGRP or its receptor are used for the prophylactic treatment of migraine. Tachykinin NK1 receptor antagonists failed as analgesics but are used for chemotherapy-induced nausea and vomiting. New, orally active somatostatin 4 receptor agonists are promising drug candidates for treating various pain conditions.

Prevalence and burden of migraine in the United States: A systematic review

BACKGROUND

This study reviewed migraine prevalence and disability gathered through epidemiologic survey studies in the United States conducted over the past three decades. We summarized these studies and evaluated changing patterns of disease prevalence and disability.

METHODS

We conducted a systematic review of US studies addressing the prevalence, disability, and/or burden of migraine, including both episodic migraine (EM) and chronic migraine (CM). A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol was used in conjunction with the PubMed search engine. Eligible studies were published before February 2022, were conducted in the United States, included representative samples, and used a case definition of migraine based on the International Classification of Headache Disorders (ICHD). The primary measure of disease burden was the Migraine Disability Assessment Scale (MIDAS). The MIDAS measures days lost due to migraine over 3 months in three domains and defines groups with moderate (Grade III) or severe disability (Grade IV) using cut-scores.

RESULTS

Of the 1609 identified records, 26 publications from 11 US population-based studies met eligibility criteria. The prevalence of migraine in the population has remained relatively consistent for the past 30 years: ranging from 11.7% to 14.7% overall, 17.1% to 19.2% in women, and 5.6% to 7.2% in men in the studies reviewed. CM prevalence is 0.91% (1.3% among women and 0.5% of men) in adults and 0.8% in adolescents. The proportion of people with migraine and moderate-to-severe MIDAS disability (Grades III-IV), has trended upward across studies from 22.0% in 2005 to 39.0% in 2012, to 43.2% in 2016, and 42.4% in 2018. A consistently higher proportion of women were assigned MIDAS Grades III/IV relative to men.

CONCLUSION

The prevalence of migraine in the United States has remained stable over the past three decades while migraine-related disability has increased. The disability trend could reflect changes in reporting, study methodology, social and societal changes, or changes in exacerbating or remediating factors that make migraine more disabling, among other hypotheses. These issues merit further investigation.

Benefit of Dietary Supplementation of Nutraceuticals as an Integrative Approach for Management of Migraine: Evidence From Preclinical and Clinical Studies

PURPOSE OF REVIEW

To provide information from preclinical and clinical studies on the biological activity and health benefits of dietary inclusion of nutraceuticals as a safe, effective, non-pharmacological approach for the treatment of migraine.

RECENT FINDINGS

There is emerging evidence of the therapeutic benefit of nutraceuticals to inhibit oxidative stress, suppress inflammation, and prevent changes in the normal gut microbiome, which are implicated in migraine pathology. Nutraceuticals can be enriched in polyphenols, which act as molecular scavengers to reduce the harmful effects of reactive oxygen species and phytosterols that suppress inflammation. Nutraceuticals also function to inhibit dysbiosis and to maintain the commensal intestinal bacteria that produce anti-inflammatory molecules including short-chain fatty acids that can act systemically to maintain a healthy nervous system. Dietary inclusion of nutraceuticals that exhibit antioxidant, anti-inflammatory, and anti-nociceptive properties and maintain the gut microbiota provides a complementary and integrative therapeutic strategy for migraine.

Improvement of comorbid anxiety and depression in patients with migraine treated with injectable preventive calcitonin gene-related peptide antagonists: Review of clinical evidence

Background

Migraine is often associated with depression and anxiety, leading to a diminished quality of life. Calcitonin gene-related peptide (CGRP) antagonists have shown promise in treating migraines, but their effects on concurrent depression and anxiety have not been clarified.

Methods

A literature review was conducted on ClinicalTrials.gov, PubMed, Ovid Medline, and EMBASE focusing on phase 3 clinical trials, post-hoc analysis studies, and real-world evidence (RWE) published in the past 5 years. The review primarily utilized patient-reported outcome tools, such as the Patient Health Questionnaire-9, Hamilton Depression Rating Scale, Beck Depression Inventory-II, generalized anxiety disorder (GAD)-7, and Hamilton Anxiety Rating Scale (HARS), to assess anxiety and depression in relation to CGRP-targeted monoclonal antibodies.

Results

Out of 260 studies, 17 met the inclusion criteria. Eptinezumab lacked sufficient evidence regarding its impact on depression and anxiety. While sufficient evidence on its effect on comorbid anxiety was not available, fremanezumab was shown to significantly improve comorbid depression in one study while not achieving statistical significance in another. Erenumab and galcanezumab showed significant improvement in comorbid depression, implying possible benefits in patients with migraine. Galcanezumab showed faster relief from depressive symptoms than other injectable CGRP antagonists. Galcanezumab also exhibited improvements in GAD-7 scores for anxiety, although not statistically significant, whereas RWE showed promising HARS scores for both galcanezumab and erenumab.

Conclusions

Galcanezumab and erenumab appear to be more effective in improving concurrent depressive and anxiety symptoms in migraine patients than fremanezumab. Notably, these psychometric questionnaires were not the primary outcome measures of the trials and were not specifically designed to investigate the effects of these medications on depression or anxiety. Further research is needed to fully understand the impact of CGRP antagonists on mental health disorders associated with migraines. These findings have implications for enhancing the overall well-being and quality of life in individuals with migraines and comorbid psychiatric conditions.

Real-world effectiveness of erenumab in Japanese patients with migraine

Background

Real-world evidence of erenumab effectiveness in migraine patients in Asia with various comorbidities and multiple previous medication failures is still limited.

Methods

A 6-month single-center cohort study of 45 patients with episodic or chronic migraine (CM) treated with erenumab was conducted. In the cohort, 60.0% were switching from other calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs), and 66.7% had ≥4 prophylaxis failures. The change in monthly migraine days (MMDs) from baseline and percentages of responders after treatment were calculated. Weekly migraine days (WMDs) were obtained at baseline and at months 1, 2 and 3 and were compared between weeks 2 and 4.

Results

In total, 36%, 47%, and 63% of patients had a ≥30% response at 1, 3, and 6 months, respectively. The cumulative percentage of patients achieving a ≥30% response over 6 months was 85%. Early responders (average ≥ 30% response at 1-3 months) accounted for 37.8%, 55.6%, and 25.9% of the total, CGRP mAb-naïve, and CGRP mAb-switching groups, respectively. Late responders (average < 30% response at 1-3 months and average ≥ 30% response at 4-6 months) accounted for 46.4%, 37.5%, and 58.8% of nonearly responders in the total, CGRP mAb-naïve, and CGRP mAb-switching groups, respectively. Mild adverse reactions were observed in 5 patients (11.1%). Wearing-off, defined as an increase in the number of WMDs ≥2 between week 2 and week 4, was observed in 2.4-12.5% at months 1-3.

Conclusion

Erenumab was effective in migraine patients. At least 4-6 months may be preferable for efficacy evaluation in patients switching to erenumab from other CGRP mAbs.

Calcitonin gene-related peptide antagonists in pregnancy: a disproportionality analysis in VigiBase®

BACKGROUND

Current evidence on the safety of calcitonin gene-related peptide antagonists (CGRP-A) in pregnancy for the treatment of both episodic and chronic migraine is scarce and does not yet provide definitive information. By querying VigiBase®, the World Health Organization global pharmacovigilance database, this study aimed to detect differences in the reporting frequency between CGRP-A and triptans in relation to pregnancy.

METHODS

Disproportionality analyses on de-duplicated safety reports collected in VigiBase® as of 31.05.2023 reporting exposure to CGRP-A in pregnancy with or without pregnancy outcomes. A Reporting Odds Ratio (ROR) with a 95% confidence interval (CI) was used as a measure of disproportionality and the threshold for the detection of a signal of disproportionate reporting was set with a 95% CI lower limit > 1.

FINDINGS

Four hundred sixty-seven safety reports reported exposure to CGRP-A in pregnancy, mostly originating from the United States of America (360/467, 77%), more frequently reported by patients (225/467, 48%), who were mainly females (431/467, 92%), and more frequently reported exposure to CGRP-A during pregnancy (400/467, 86%). Compared to triptans, no signals of disproportionate reporting were detected with CGRP-A either for the overall reporting of pregnancy-related safety reports (ROR 0.91, 95% CI 0.78-1.06), for the reporting of pregnancy outcomes (maternal and/or foetal/neonatal, ROR 0.54, 95% CI 0.45-0.66), or for the reporting of foetal/neonatal outcomes (ROR 0.53, 95% CI 0.41-0.68).

CONCLUSIONS

This study showed that, to date, there are no signals of increased reporting with CGRP-A compared to triptans in relation to pregnancy in VigiBase®. Future pharmacovigilance studies are needed to confirm these findings.

Metabolic and toxicological considerations regarding CGRP mAbs and CGRP antagonists to treat migraine in COVID-19 patients: a narrative review

INTRODUCTION

Migraine pharmacological therapies targeting calcitonin gene-related peptide (CGRP), including monoclonal antibodies and gepants, have shown clinical effect and optimal tolerability. Interactions between treatments of COVID-19 and CGRP-related drugs have not been reviewed.

AREAS COVERED

An overview of CGRP, a description of the characteristics of each CGRP-related drug and its response predictors, COVID-19 and its treatment, the interactions between CGRP-related drugs and COVID-19 treatment, COVID-19 and vaccination-induced headache, and the neurological consequences of Covid-19.

EXPERT OPINION

Clinicians should be careful about using gepants for COVID-19 patients, due to the potential drug interactions with drugs metabolized via CYP3A4 cytochrome. In particular, COVID-19 treatment (especially nirmatrelvir packaged with ritonavir, as Paxlovid) should be considered cautiously. It is advisable to stop or adjust the dose (10 mg atogepant when used for episodic migraine) of gepants when using Paxlovid (except for zavegepant). CGRP moncolconal antibodies (CGRP-mAbs) do not have drug - drug interactions, but a few days' interval between a COVID-19 vaccination and the use of CGRP mAbs is recommended to allow the accurate identification of the possible adverse effects, such as injection site reaction. Covid-19- and vaccination-related headache are known to occur. Whether CGRP-related drugs would be of benefit in these circumstances is not yet known.

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.

Real-world evidence on the economic implications of CGRP-mAbs as preventive treatment of migraine

BACKGROUND

Calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) are approved in Europe as preventive treatment of migraine in patients with at least four monthly migraine days. Migraine gives rise to direct healthcare expenditures, but most of the economic burden of migraine is socioeconomic. Evidence on the socioeconomic implications of CGRP-mAbs is, however, limited. There is an increasing interest in supplementing evidence from randomised controlled trials (RCTs) with real-world evidence (RWE) to aid clinical decision making and inform decision making for migraine management. The objective of this study was to generate RWE on the health economic and socioeconomic implications of administering CGRP-mAbs to patients with chronic migraine (CM) and episodic migraine (high-frequency episodic migraine (HFEM), and low-frequency episodic migraine (LFEM)).

METHODS

Real-world data (RWD) on Danish patients with CM, HFEM, and LFEM were collected via two Danish patient organisations and two informal patient networks and used in a tailored economic model. Treatment effects of CGRP-mAbs on health economic and socioeconomic outcomes were estimated using a sub-sample of patients with CM who receive CGRP-mAb treatment.

RESULTS

A total of 362 patients (CM: 199 [55.0%], HFEM: 80 [22.1%], LFEM: 83 [22.9%]) were included in the health economic model (mean age 44.1 ± 11.5, 97.5% female, 16.3% received treatment with CGRP-mAbs), and 303 patients were included in the socioeconomic model (15.2% received treatment with CGRP-mAbs). Health economic savings from initiating CGRP-mAb treatment totalled €1,179 per patient with CM per year on average (HFEM: €264, LFEM: €175). Socioeconomic gains from initiating CGRP-mAb treatment totalled an average gross domestic product (GDP) gain of €13,329 per patient with CM per year (HFEM: €10,449, LFEM: €9,947).

CONCLUSION

Our results indicate that CGRP-mAbs have the potential to reduce both health economic expenditures and the socioeconomic burden of migraine. Health economic savings are used as a basis for health technology assessments (HTAs) of the cost-effectiveness of new treatments, which implies that important socioeconomic gains may not be given enough importance in decision making for migraine management.

Zavegepant: First Approval

Zavegepant is a third generation, small-molecule, calcitonin gene-related peptide (CGRP) receptor antagonist being developed by Pfizer, under a license from Bristol-Myers Squibb, for the prevention and treatment of chronic and episodic migraine. In March 2023, zavegepant nasal spray (ZAVZPRET™) received its first approval in the USA for the acute treatment of migraine with or without aura in adults. Clinical development of an oral formulation of zavegepant is currently underway. This article summarizes the milestones in the development of zavegepant leading to this first approval for the acute treatment of migraine with or without aura in adults.

Reversal of Peripheral Neuropathic Pain by the Small-Molecule Natural Product Narirutin via Block of Nav1.7 Voltage-Gated Sodium Channel

Neuropathic pain is a refractory chronic disease affecting millions of people worldwide. Given that present painkillers have poor efficacy or severe side effects, developing novel analgesics is badly needed. The multiplex structure of active ingredients isolated from natural products provides a new source for phytochemical compound synthesis. Here, we identified a natural product, Narirutin, a flavonoid compound isolated from the Citrus unshiu, showing antinociceptive effects in rodent models of neuropathic pain. Using calcium imaging, whole-cell electrophysiology, western blotting, and immunofluorescence, we uncovered a molecular target for Narirutin's antinociceptive actions. We found that Narirutin (i) inhibits Veratridine-triggered nociceptor activities in L4-L6 rat dorsal root ganglion (DRG) neurons, (ii) blocks voltage-gated sodium (Na_V) channels subtype 1.7 in both small-diameter DRG nociceptive neurons and human embryonic kidney (HEK) 293 cell line, (iii) does not affect tetrodotoxin-resistant (TTX-R) Na_V channels, and (iv) blunts the upregulation of Na_v1.7 in calcitonin gene-related peptide (CGRP)-labeled DRG sensory neurons after spared nerve injury (SNI) surgery. Identifying Na_v1.7 as a molecular target of Narirutin may further clarify the analgesic mechanism of natural flavonoid compounds and provide an optimal idea to produce novel selective and efficient analgesic drugs.

Immunologic aspects of migraine: A review of literature

Migraine headaches are highly prevalent, affecting 15% of the population. However, despite many studies to determine this disease's mechanism and efficient management, its pathophysiology has not been fully elucidated. There are suggested hypotheses about the possible mediating role of mast cells, immunoglobulin E, histamine, and cytokines in this disease. A higher incidence of this disease in allergic and asthma patients, reported by several studies, indicates the possible role of brain mast cells located around the brain vessels in this disease. The mast cells are more specifically within the dura and can affect the trigeminal nerve and cervical or sphenopalatine ganglion, triggering the secretion of substances that cause migraine. Neuropeptides such as calcitonin gene-related peptide (CGRP), neurokinin-A, neurotensin (NT), pituitary adenylate-cyclase-activating peptide (PACAP), and substance P (SP) trigger mast cells, and in response, they secrete pro-inflammatory and vasodilatory molecules such as interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) as a selective result of corticotropin-releasing hormone (CRH) secretion. This stress hormone contributes to migraine or intensifies it. Blocking these pathways using immunologic agents such as CGRP antibody, anti-CGRP receptor antibody, and interleukin-1 beta (IL-1β)/interleukin 1 receptor type 1 (IL-1R1) axis-related agents may be promising as potential prophylactic migraine treatments. This review is going to summarize the immunological aspects of migraine.

CGRP Plasma Levels Correlate with the Clinical Evolution and Prognosis of Hospitalized Acute COVID-19 Patients

SARS-CoV-2 is the etiological agent of COVID-19, an extremely heterogenous disease that can cause severe respiratory failure and critical illness. To date, reliable biomarkers allowing for early patient stratification according to disease severity are still lacking. Calcitonin gene-related peptide (CGRP) is a vasoactive neuropeptide involved in lung pathophysiology and immune modulation and is poorly investigated in the COVID-19 context. In this observational, prospective cohort study, we investigated the correlation between CGRP and clinical disease evolution in hospitalized moderate to severe COVID-19 patients. Between January and May 2021 (Italian third pandemic wave), 135 consecutive SARS-CoV-2 patients were diagnosed as being eligible for the study. Plasma CGRP level evaluation and routine laboratory tests were performed on blood samples collected at baseline and after 7 days of hospitalization. At baseline, the majority our patients had a moderate to severe clinical presentation, and higher plasma CGRP levels predicted a higher risk of in-hospital negative evolution (odds-ratio OR 2.84 [IQR 1.07-7.51]) and were correlated with pulmonary intravascular coagulopathy (OR 2.92 [IQR 1.19-7.17]). Finally, plasma CGRP levels were also correlated with plasma IP10 levels. Our data support a possible crosstalk between the lung and the neuroimmune axis, highlighting a crucial role for plasma CGRP in sustaining COVID-19-related hyperinflammation.

CGRP-Targeted Therapy for Episodic and Chronic Cluster Headache

PURPOSE OF REVIEW

Chronic cluster headache (CH) substantially affects patients' quality of life, and treatment remains challenging. The current article reviewed controlled studies for new treatment options targeting calcitonin gene-related peptide (CGRP) or its receptors in CH and discussed the current gaps and future directions for the treatment of chronic CH.

RECENT FINDINGS

Two anti-CGRP monoclonal antibodies (i.e., galcanezumab and fremanezumab) completed randomized-control trials for efficacy for the preventive treatment of episodic and chronic CH. Galcanezumab was effective for preventing episodic CH but not chronic CH. Fremanezumab was ineffective in preventing episodic and chronic CH. Studies for other anti-CGRP monoclonal antibodies and CGRP antagonists are still pending for results. There are no randomized controlled trials for CGRP-targeted therapies that showed efficacy for chronic CH prevention. The different responses to galcanezumab between episodic and chronic CH may be due to the study design, i.e., the allowance of concomitant preventive therapies in the chronic CH study but not in the episodic CH study. Another reason for the discrepancies is the different roles and sensitivity of CGRP in chronic CH.

Novel Migraine Therapies May Reduce Public and Personal Disadvantages for People with Migraine

The introduction of new drug classes for migraine, such as monoclonal antibodies that target the calcitonin gene-related peptide (CGRP) or its receptor and small-molecule antagonists of CGRP, have opened a new scenario in a large population of individuals suffering from migraines. The provision of an effective and safe therapy can help overcome the high social and personal costs together with the burden of this disease by offering social, work and economic recovery to the people affected by migraine. Whether the satisfaction of personal and collective unmet needs will be achieved in the vast majority of migraine sufferers now depends only on the efficiency of the organizational care structures dedicated to this socially impactful disease. This path will offer personal benefits and significant psychosocial relief that will help to reduce the enormous current healthcare expenditure necessary for the management of the huge number of individuals suffering from migraines. The new pharmacological classes for prevention must be applied as an interdiction to the chronic phase to express their full rehabilitation potential.