Calcitonin Gene-Related Peptide (CGRP) and Migraine Current Understanding and State of Development

Plasma calcitonin gene-related peptide levels in idiopathic intracranial hypertension: an exploratory study

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a debilitating condition characterized by increased intracranial pressure often presenting with chronic migraine-like headache. Calcitonin gene-related peptide (CGRP) plays an important pathophysiological role in primary headaches such as migraine, whilst its role in IIH has not yet been established.

METHODS

This longitudinal exploratory study included patients with IIH, episodic migraine (EM) in a headache-free interval and healthy controls (HC). Blood samples were collected from a cubital vein and plasma CGRP (pCGRP) levels were measured by standardized ELISA.

RESULTS

A total of 26 patients with IIH (mean age 33.2 years [SD 9.2], 88.5% female, median BMI 34.8 kg/m2 [IQR 30.0-41.4]), 30 patients with EM (mean age 27.6 years [7.5], 66.7% female) and 57 HC (mean age 25.3 years [5.2], 56.1% female) were included. pCGRP levels displayed a wide variation in IIH as well as in EM and HC on a group-level. Within IIH, those with migraine-like headache had significantly higher pCGRP levels than those with non-migraine-like headache (F(2,524) = 84.79; p < 0.001) and headache absence (F(2,524) = 84.79; p < 0.001) throughout the observation period, explaining 14.7% of the variance in pCGRP levels. CGRP measurements showed strong intraindividual agreement in IIH (ICC 0.993, 95% CI 0.987-0.996, p < 0.001). No association was found between pCGRP levels and ophthalmological parameters.

CONCLUSIONS

Although interindividual heterogeneity of pCGRP levels is generally high, migraine-like headache seems to be associated with higher pCGRP levels. CGRP may play a role in the headache pathophysiology at least in a subgroup of IIH.

Efficacy of various exercise interventions for migraine treatment: A systematic review and network meta-analysis

OBJECTIVE

To compare various exercise modalities' efficacy on migraine frequency, intensity, duration, and disability.

BACKGROUND

Exercise has been shown to be an effective intervention to reduce migraine symptoms and disability; however, no clear evidence exists regarding the most effective exercise modalities for migraine treatment.

METHODS

A systematic review was performed in PubMed, PEDro, Web of Science, and Google Scholar. Clinical trials that analyzed the efficacy of various exercise modalities in addressing the frequency, intensity, duration, and disability of patients with migraine were included. Eight network meta-analyses based on frequentist (F) and Bayesian (B) models were developed to estimate the direct and indirect evidence of various exercise modalities. Standardized mean difference (SMD) and 95% confidence (CI) and credible intervals (CrI) were calculated for each treatment effect based on Hedge's g and p scores to rank the modalities.

RESULTS

We included 28 studies with 1501 migraine participants. Yoga (F: SMD -1.30; 95% CI -2.09, -0.51; B: SMD -1.33; 95% CrI -2.21, -0.45), high-intensity aerobic exercise (F: SMD -1.30; 95% CI -2.21, -0.39; B: SMD -1.17; 95% CrI -2.20, -0.20) and moderate-intensity continuous aerobic exercise (F: SMD -1.01; 95% CI -1.63, -0.39; B: SMD -1.06; 95% CrI -1.74, -0.38) were significantly superior to pharmacological treatment alone for decreasing migraine frequency based on both models. Only yoga (F: SMD -1.40; 95% CI -2.41, -0.39; B: SMD -1.41; 95% CrI -2.54, -0.27) was significantly superior to pharmacological treatment alone for reducing migraine intensity. For diminishing migraine duration, high-intensity aerobic exercise (F: SMD -1.64; 95% CI -2.43, -0.85; B: SMD -1.56; 95% CrI -2.59, -0.63) and moderate-intensity continuous aerobic exercise (SMD -0.96; 95% CI -1.50, -0.41; B: SMD -1.00; 95% CrI -1.71, -0.31) were superior to pharmacological treatment alone.

CONCLUSION

Very low-quality evidence showed that yoga, high- and moderate-intensity aerobic exercises were the best interventions for reducing migraine frequency and intensity; high- and moderate-intensity aerobic exercises were best for decreasing migraine duration; and moderate-intensity aerobic exercise was best for diminishing disability.

Reporting Quality and Risk of Bias Analysis of Published RCTs Assessing Anti-CGRP Monoclonal Antibodies in Migraine Prophylaxis: A Systematic Review

Objective: Phase II/III randomized clinical trials (RCTs) are vulnerable to many types of bias beyond randomization. Insights into the reporting quality of RCTs involving migraine patients treated with monoclonal antibodies targeting the calcitonin gene-related peptide system (anti-CGRP MAbs) are currently lacking. Our aim was to analyze the reporting quality of phase II/III RCTs involving migraine patients treated with anti-CGRP MAbs. Methods: A systematic search was performed on the PubMed and EMBASE databases, according to PRISMA guidelines, for relevant RCTs in either episodic or chronic migraine prevention. Additionally, an adapted version of the 2010 CONSORT statement checklist was utilized. The ROBvis online tool was used to document the risk of bias. Results: From the initially identified 179 articles, we finally found 31 RCTs that were eligible for evaluation. The average CONSORT compliance was 88.7% (69.7-100%), while 93.5% (N = 29) of the articles had a compliance greater than 75%. Twenty-eight CONSORT items were reported in more than 75% of the articles. The average compliance of the analyzed RCTs was 93.9% for Galcanezumab, 91.3% for Fremanezumab, followed by 85.4% for Erenumab and Eptinezumab studies. Implementation of the ROB2 tool showed some concerning "missing information" arising from the inadequate reporting. Specifically, 50% of the studies (N = 16) were categorized as having inadequate information regarding the randomization process. Conclusions: Adequate reporting quality was disclosed in the evaluated RCTs with anti-CGRP MAbs in migraine prevention. However, some methodological issues need to be highlighted to be addressed in future studies assessing the efficacy of new molecules targeting CGRP or other candidate pathways implicated in migraine pathophysiology.

Topical application of calcitonin gene-related peptide as a regenerative, antifibrotic, and immunomodulatory therapy for corneal injury

Calcitonin gene-related peptide (CGRP) is a multifunctional neuropeptide abundantly expressed by corneal nerves. Using a murine model of corneal mechanical injury, we found CGRP levels in the cornea significantly reduced after injury. Topical application of CGRP as an eye drop accelerates corneal epithelial wound closure, reduces corneal opacification, and prevents corneal edema after injury in vivo. CGRP promotes corneal epithelial cell migration, proliferation, and the secretion of laminin. It reduces TGF-β1 signaling and prevents TGF-β1-mediated stromal fibroblast activation and tissue fibrosis. CGRP preserves corneal endothelial cell density, morphology, and pump function, thus reducing corneal edema. Lastly, CGRP reduces neutrophil infiltration, macrophage maturation, and the production of inflammatory cytokines in the cornea. Taken together, our results show that corneal nerve-derived CGRP plays a cytoprotective, pro-regenerative, anti-fibrotic, and anti-inflammatory role in corneal wound healing. In addition, our results highlight the critical role of sensory nerves in ocular surface homeostasis and injury repair.

Potential mechanisms for osteopathic manipulative treatment to alleviate migraine-like pain in female rats

Introduction

Migraines are the leading cause of disability in the United States, and the use of non-pharmaceutical treatments like osteopathic manipulative treatment (OMT) has shown promise. Despite its potential, the lack of mechanistic understanding has hindered widespread adoption. This study aims to investigate the efficacy of OMT in treating acute migraines and unravel its underlying mechanisms of action.

Methods

Female rats were subjected to a "two-hit" approach to induce migraine-like pain. This involved bilateral injections of Complete Freund's Adjuvant (CFA) into the trapezius muscle (1st hit) followed by exposure to Umbellulone, a human migraine trigger, on Day 6 post-CFA (2nd hit). Soft tissue and articulatory techniques were applied to the cervical region for acute abortive or repeated prophylactic treatment. Cutaneous allodynia and trigeminal system activation were assessed through behavioral tests and immunohistochemical staining.

Results

Following Umbellulone inhalation, CFA-primed rats exhibited periorbital and hind paw allodynia. Immediate application of OMT after Umbellulone inhalation as an abortive treatment partially alleviated cutaneous allodynia. With OMT applied thrice as a prophylactic measure, complete suppression of tactile hypersensitivity was observed. Prophylactic OMT also prevented the increase of c-fos signals in the trigeminal nucleus caudalis and the elevation of calcitonin gene-related peptide expression in trigeminal ganglia induced by CFA and Umbellulone exposure at 2 h post-inhalation.

Discussion

These findings provide mechanistic insights into OMT's migraine-relief potential and underscore its viability as a non-pharmacological avenue for managing migraines.

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.

A Brief Review of Gepants

PURPOSE OF REVIEW

Gepants are small molecules that antagonize calcitonin gene-related peptide (CGRP) receptors. Due to their favorable side effect profile and versatility in treating headaches acutely and preventively, gepants are preferred over triptans. We will cover the indications for the four FDA-approved gepants in adults: rimegepant, atogepant, ubrogepant, and zavegepant. This review will illustrate how gepants will continue to revolutionize the acute and preventive treatment of headaches.

RECENT FINDINGS

Gepants are now available in oral tablet, dissolving tablet, and intra-nasal spray formulations. Recent studies have shown promising utility in treating the pre-headache or prodromal phase. They have favorable tolerability, no evidence for association with medication overuse, and remain a safer alternative in those who have cerebrovascular risk factors. Additional research is needed to explore occurrence of Raynaud's phenomenon in participants treated with gepants, as it has been associated with CGRP monoclonal antibodies, but are not extensively studied in gepants. Gepants are expected to play a significant role in the next generation of migraine treatments.

Prescription of therapeutic exercise in migraine, an evidence-based clinical practice guideline

The main objective of this clinical practice guideline is to provide a series of recommendations for healthcare and exercise professionals, such as neurologists, physical therapists, and exercise physiologists, regarding exercise prescription for patients with migraine.This guideline was developed following the methodology and procedures recommended in the Appraisal of Guidelines for Research and Evaluation (AGREE). The quality of evidence and strength of recommendations were evaluated with the Scottish Intercollegiate Guidelines Network (SIGN). A systematic literature review was performed and an established appraisal process was employed to rate the quality of relevant scientific research (Grading of Recommendations Assessment, Development, and Evaluation methodology).The evaluation of the current evidence, the elaboration of the grades of recommendation, and their validation show a B grade of recommendation for aerobic exercise, moderate-continuous aerobic exercise, yoga, and exercise and lifestyle recommendations for the improvement of symptoms, disability, and quality of life in patients with migraine. Relaxation techniques, high-intensity interval training, low-intensity continuous aerobic exercise, exercise and relaxation techniques, Tai Chi, and resistance exercise obtained a C grade of recommendation for the improvement of migraine symptoms and disability.

Photophobia and migraine outcome during treatment with galcanezumab

Background

Calcitonin gene-related peptide (CGRP) plays a pivotal role in migraine physiology, not only regarding migraine pain but also associated symptoms such as photophobia. The aim of the present study was to assess monoclonal antibodies targeting CGRP efficacy not only in terms of headache and migraine frequency and disability but also in reducing ictal photophobia.

Material and methods

This is a retrospective observational study, conducted at the Headache Center-ASST Spedali Civili Brescia. All patients in monthly treatment with galcanezumab with at least a 6-month follow-up in September 2022 with reported severe photophobia during migraine attacks were included. Data regarding headache frequency, analgesics consumption, and migraine disability were collected quarterly. Moreover, patients were asked the following information regarding photophobia: (1) whether they noticed an improvement in photophobia during migraine attacks since galcanezumab introduction; (2) the degree of photophobia improvement (low, moderate, and high); and (3) timing photophobia improvement.

Results

Forty-seven patients were enrolled in the present study as they met the inclusion criteria. Seventeen patients had a diagnosis of high-frequency episodic migraine and 30 of chronic migraine. From baseline to T3 and T6, a significant improvement in terms of headache days (19.2 ± 7.6 vs. 8.6 ± 6.8 vs. 7.7 ± 5.7; p < 0.0001), migraine days (10.4 ± 6.7 vs. 2.9 ± 4.3 vs. 3.6 ± 2.8; p < 0.0001), analgesics consumption (25.1 ± 28.2 vs. 7.6 ± 7.5 vs. 7.6 ± 8.1; p < 0.0001), MIDAS score (82.1 ± 48.4 vs. 21.6 ± 17.6 vs. 18.1 ± 20.5; p < 0.0001), and HIT-6 score (66.2 ± 6.2 vs. 57.2 ± 8.6 vs. 56.6 ± 7.6; p < 0.0001) was found. Thirty-two patients (68.1%) reported a significant improvement in ictal photophobia, with over half of the patients reporting it within the first month of treatment. Photophobia improvement was more frequent in patients with episodic migraine (p = 0.02) and triptans responders (p = 0.03).

Conclusions

The present study confirms previous reports regarding galcanezumab efficacy beyond migraine frequency. In particular, over 60% of patients, in our cohort, documented a significant improvement also in reducing ictal photophobia. This improvement was, in most patients, moderate to high, and within the first 6 months of treatment, regardless of the clinical response on migraine frequency.

Advances in pharmacotherapy for the prophylactic treatment of resistant and refractory migraine

INTRODUCTION

Refractory migraine is associated with low quality of life and great socioeconomic burden. Despite high need for effective, tolerable preventive therapies, there has been little research on potential therapeutic options. Monoclonal antibodies (mAbs) against Calcitonin Gene-Related Peptide (CGRP) are the first preventive therapeutic approach for migraine based on the underlying pathophysiology.

AREAS COVERED

Following a brief introduction into the term 'refractory migraine,' the authors reviewavailable treatment options, focusing on current phase III trials of substances acting on the CGRP pathway.

EXPERT OPINION

No uniform definition for refractory migraine is available. The vast majority of proposals recommend treatment failure of 2-4 drug classes as a key diagnostic criterion. Phase III studies on CGRP-(receptor) mAbs demonstrated excellent efficacy and tolerability in patients with chronic and episodic migraine including subjects with multiple unsuccessful conventional therapy attempts. However, more comparator trials showing superiority of mAbs versus oral preventatives, such as the HER-MEs study are needed. In summary, with the CGRP antibodies, a group of drugs has entered the market which will most likely not only significantly improve the quality of life of many individual migraine patients but could also reduce indirect health-care costs associated with migraine by reducing recurrent medical consultations.

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

Calcitonin gene-related peptide (CGRP), a 37 amino-acid neuropeptide found mostly in peptidergic sensory C-fibers, has been suggested to be implicated in the pathogenesis of migraine, which is one of the most common neurological disorders seen in medical practice, affecting almost 16% of the US population. While previously thought to be a vascular condition, migraine attacks are the result of neurogenic inflammation and peripheral/central sensitization through dysfunctional activation of the trigeminovascular system. To date, two classes of therapeutic agents have been developed to interrupt the function of CGRP: CGRP-targeted monoclonal antibodies (mAbs) and small-molecule antagonists (gepants). There are currently four CGRP-targeted mAbs and three gepants that are US Food and Drug Administration (FDA) approved for the treatment of migraine. Multiple phase II and III studies have established the efficacies and tolerability of these treatments. Previously, we reviewed the fundamental role of CGRP in migraine pathogenesis. Here, we discuss in depth the clinical evidence (randomized controlled trials and real-world studies), safety, and tolerability of CGRP-targeted mAbs and gepants for treating migraine.

New Insights on Metabolic and Genetic Basis of Migraine: Novel Impact on Management and Therapeutical Approach

Migraine is a hereditary disease, usually one-sided, sometimes bilateral. It is characterized by moderate to severe pain, which worsens with physical activity and may be associated with nausea and vomiting, may be accompanied by photophobia and phonophobia. The disorder can occur at any time of the day and can last from 4 to 72 h, with and without aura. The pathogenic mechanism is unclear, but extensive preclinical and clinical studies are ongoing. According to electrophysiology and imaging studies, many brain areas are involved, such as cerebral cortex, thalamus, hypothalamus, and brainstem. The activation of the trigeminovascular system has a key role in the headache phase. There also appears to be a genetic basis behind the development of migraine. Numerous alterations have been identified, and in addition to the genetic cause, there is also a close association with the surrounding environment, as if on the one hand, the genetic alterations may be responsible for the onset of migraine, on the other, the environmental factors seem to be more strongly associated with exacerbations. This review is an analysis of neurophysiological mechanisms, neuropeptide activity, and genetic alterations that play a fundamental role in choosing the best therapeutic strategy. To date, the goal is to create a therapy that is as personalized as possible, and for this reason, steps forward have been made in the pharmacological field in order to identify new therapeutic strategies for both acute treatment and prophylaxis.

Real-world impact of fremanezumab on migraine symptoms and resource utilization in the United States

Background

Fremanezumab, a fully humanized monoclonal antibody (IgG2Δa) that selectively targets calcitonin gene-related peptide (CGRP), is approved for migraine prevention in adults. Real-world data on the effectiveness of fremanezumab are limited. This retrospective, observational cohort study assessed patient-reported migraine symptoms, health care resource utilization (HCRU), and direct medical costs before and after fremanezumab treatment initiation.

Methods

Data were extracted from September 2018 through June 2020 from the Midwest component of EMRClaims+®, an integrated health services database containing > 20 million medical records from national commercial insurance claims, Medicare claims, and regional electronic medical records. Patients included in the cohort analysis were aged ≥ 18 years and were administered fremanezumab, with enrollment or treatment history for ≥ 6 months prior (pre-index) to initiating fremanezumab (index date) and ≥ 1 month after the index date (post-index), and without pregnancy or pregnancy-related encounters during the study period. Patient-reported headache frequency, migraine pain intensity (MPI), composite migraine symptoms, and HCRU were assessed pre-index and ≥ 1 month after fremanezumab initiation. Wilcoxon signed-rank tests were used to compare means of migraine symptoms and outcomes and HCRU before and after fremanezumab initiation.

Results

Overall, 172 patients were eligible for analysis. Of patients who self-reported (n = 129), 83.7% reported improvement in headache frequency or symptoms after fremanezumab treatment. Specifically, headache frequency decreased by 63% after fremanezumab initiation: mean (standard deviation) headache frequency was 22.24 (9.29) days per month pre-index versus 8.24 (7.42) days per month post-index (P < 0.0001). Mean MPI also decreased by 18% after fremanezumab initiation: MPI was 5.47 (3.19) pre-index versus 4.51 (3.34) post-index (P = 0.014). Mean emergency room (ER) visits per month decreased from 0.72 to 0.54 (P = 0.003), and mean outpatient visits per month decreased from 1.04 to 0.81 (P < 0.001). Mean hospitalizations per month decreased, but the results did not reach statistical significance (P = 0.095). Hospitalization and ER costs decreased, while outpatient costs increased, from pre-index to post-index, but differences were not statistically significant (P ≥ 0.232).

Conclusions

Significant reductions in headache frequency, MPI, and HCRU were observed after fremanezumab initiation in patients with migraine in a US real-world setting.

Roles of calcitonin gene-related peptide in the skin, and other physiological and pathophysiological functions

Skin immunity is regulated by many mediator molecules. One is the neuropeptide calcitonin gene-related peptide (CGRP). CGRP has roles in regulating the function of components of the immune system including T cells, B cells, dendritic cells (DCs), endothelial cells (ECs), and mast cells (MCs).

Herein we discuss actions of CGRP in mediating inflammatory and vascular effects in various cutaneous models and disorders.

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CGRP can help to recruit immune cells through endothelium-dependent vasodilation.

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CGRP plays an important role in the pathogenesis of neurogenic inflammation.

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Functions of many components in the immune system are influenced by CGRP.

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CGRP regulates various inflammatory processes in human skin by affecting different cell-types.

Monoclonal Antibodies for Chronic Pain Treatment: Present and Future

Chronic pain remains a major problem worldwide, despite the availability of various non-pharmacological and pharmacological treatment options. Therefore, new analgesics with novel mechanisms of action are needed. Monoclonal antibodies (mAbs) are directed against specific, targeted molecules involved in pain signaling and processing pathways that look to be very effective and promising as a novel therapy in pain management. Thus, there are mAbs against tumor necrosis factor (TNF), nerve growth factor (NGF), calcitonin gene-related peptide (CGRP), or interleukin-6 (IL-6), among others, which are already recommended in the treatment of chronic pain conditions such as osteoarthritis, chronic lower back pain, migraine, or rheumatoid arthritis that are under preclinical research. This narrative review summarizes the preclinical and clinical evidence supporting the use of these agents in the treatment of chronic pain.

Pharmacologic agents directed at the treatment of pain associated with maladaptive neuronal plasticity

INTRODUCTION

The definition of nociplastic pain in 2016 has changed the way maladaptive chronic pain is viewed in that it may emerge without neural lesions or neural disease. Many endogenous and pharmacologic substances are being investigated for their role in treating the pain associated with neuronal plasticity.

AREAS COVERED

The authors review promising pharmacologic agents for the treatment of pain associated with maladaptive neuronal plasticity. The authors then provide the reader with their expert opinion and provide their perspectives for the future.

EXPERT OPINION

An imbalance between the amplification of ascending pain signals and the poor activation of descending inhibitory signals may be at the root of many chronic pain syndromes. The inhibitory activity of noradrenaline reuptake may play a role in neuropathic and nociplastic analgesia. A better understanding of the brain's pain matrix, its signaling cascades, and the complex bidirectional communication between the immune system and the nervous system may help meet the urgent and unmet medical need for safe, effective chronic pain treatment, particularly for pain with a neuropathic and/or nociplastic component.

CGRP measurements in human plasma - a methodological study

Background

Calcitonin gene-related peptide plasma levels have frequently been determined as a biomarker for primary headaches. However, published data is often inconsistent resulting from different methods that are not precisely described in most studies.

Methods

We applied a well-proven enzyme-linked immunosorbent assay to measure calcitonin gene-related peptide concentrations in human blood plasma, we modified parameters of plasma preparation and protein purification and used calcitonin gene-related peptide-free plasma for standard solutions, which are described in detail.

Results

Calcitonin gene-related peptide levels are stable in plasma with peptidase inhibitors and after deep-freezing. Calcitonin gene-related peptide standard solutions based on synthetic intercellular fluid or pooled plasma with pre-absorbed calcitonin gene-related peptide influenced the measurements but yielded both comprehensible results. In a sample of 56 healthy subjects the calcitonin gene-related peptide plasma levels varied considerably from low (<50 pg/mL) to very high (>500 pg/mL) values. After a 12-hour exposure of these subjects to normobaric hypoxia the individual calcitonin gene-related peptide levels remained stable.

Conclusion

Buffering with peptidase inhibitors and immediate freezing or processing of plasma samples is essential to achieve reliable measurements. Individuals show considerable differences and partly high calcitonin gene-related peptide plasma levels without detectable pathological reason. Thus plasma measurements are suited particularly to follow calcitonin gene-related peptide levels in longitudinal studies.

The use of data for this study was approved by the Ethics Committee of the Medical

University of Innsbruck (https://www.i-med.ac.at/ethikkommission/; EK Nr: 1242/2017).

Magnesium: Biochemistry, Nutrition, Detection, and Social Impact of Diseases Linked to Its Deficiency

Magnesium plays an important role in many physiological functions. Habitually low intakes of magnesium and in general the deficiency of this micronutrient induce changes in biochemical pathways that can increase the risk of illness and, in particular, chronic degenerative diseases. The assessment of magnesium status is consequently of great importance, however, its evaluation is difficult. The measurement of serum magnesium concentration is the most commonly used and readily available method for assessing magnesium status, even if serum levels have no reliable correlation with total body magnesium levels or concentrations in specific tissues. Therefore, this review offers an overview of recent insights into magnesium from multiple perspectives. Starting from a biochemical point of view, it aims at highlighting the risk due to insufficient uptake (frequently due to the low content of magnesium in the modern western diet), at suggesting strategies to reach the recommended dietary reference values, and at focusing on the importance of detecting physiological or pathological levels of magnesium in various body districts, in order to counteract the social impact of diseases linked to magnesium deficiency.

New drug approvals for 2020: Synthesis and clinical applications

53 New drugs including 38 chemical entities and 15 biologics were approved by the U.S. Food and Drug Administration during 2020. Among the marketed drugs, 34 new small molecule drugs and 4 new diagnostic agents with privileged structures and novel clinical applications represent as promising leads for the development of new drugs with the similar indications and improved therapeutic efficacy. This review is mainly focused on the clinical applications and synthetic methods of 34 small-molecule drugs newly approved by the FDA in 2020.

No "Wearing-Off Effect" Seen in Quarterly or Monthly Dosing of Fremanezumab: Subanalysis of a Randomized Long-Term Study

OBJECTIVE

To evaluate whether quarterly or monthly administration of fremanezumab for migraine prevention exhibits a pattern of decreased efficacy toward the end of the dosing interval (wearing-off effect).

BACKGROUND

The main goals of migraine preventive treatment are to reduce the frequency, severity, and duration of migraine attacks, and migraine-associated disability. Wearing-off refers to the phenomenon whereby clinical symptoms return or worsen before the next dose of a drug is due and has been reported previously with migraine preventive medications.

DESIGN AND METHODS

This was a long-term, 12-month, multicenter, randomized, double-blind, parallel-group phase 3 study (NCT02638103) that included chronic (CM) and episodic migraine (EM) patients who rolled over from the 12-week phase 3 HALO CM (NCT02621931) and EM trials (NCT02629861), as well as an additional subset of 312 new patients. Patients with CM or EM received fremanezumab either monthly or quarterly. In this post hoc analysis, for selected months, the difference in the average number of migraine days between weeks 1-2 and weeks 3-4, between weeks 1-3 and week 4, and between weeks 1-2 and weeks 11-12 were calculated.

RESULTS

A total of 1890 patients (CM, 1110; EM, 780) were enrolled. At months 3, 6, 9, and 15, there were no substantial differences in mean weekly migraine days between weeks 1-2 and weeks 3-4 or between weeks 1-3 and week 4 with quarterly or monthly fremanezumab in the CM or EM subgroups. There were no substantial increases in mean weekly migraine days between weeks 1-2 and weeks 11-12 during the first quarter of treatment (months 1-3) or the second quarter of treatment (months 4-6) with quarterly or monthly fremanezumab in the CM or EM subgroups. Across both dosing subgroups in CM and EM patients, the mean weekly number of migraine days decreased substantially (30%-42%) during the first 2 weeks; decreases in weekly migraine days remained steady during the last 2 weeks of the first quarter, with a similar maintenance of response during the second quarter.

CONCLUSIONS

This analysis of data from a long-term, phase 3 study showed that patients receiving quarterly fremanezumab or monthly fremanezumab did not experience a wearing-off effect toward the end of the dosing interval.

Fremanezumab: a disease-specific option for the preventive treatment of migraine, including difficult-to-treat migraine

Fremanezumab is a fully humanized monoclonal antibody (IgG2Δa) that targets calcitonin gene-related peptide (CGRP), a key neuropeptide involved in the pathophysiology of migraine. Fremanezumab is approved for quarterly and monthly subcutaneous dosing for the preventive treatment of migraine in adults. The phase 3 clinical development program for fremanezumab aimed to evaluate the efficacy of this preventive treatment across different patient populations, including those with difficult-to-treat migraine. Two pivotal 12-week, phase 3, placebo-controlled studies investigated quarterly and monthly dosing of fremanezumab in participants with chronic migraine (HALO CM) and episodic migraine (HALO EM). The efficacy of fremanezumab was further explored in individuals with difficult-to-treat chronic or episodic migraine in the 12-week FOCUS study, which enrolled participants who had previously experienced an inadequate response to 2-4 pharmacological classes of migraine preventive medications. The long-term efficacy of fremanezumab was assessed in a 12-month long-term study (HALO LTS), which enrolled participants completing the 12-week HALO studies and new participants. Across these studies, treatment with fremanezumab dosed quarterly or monthly provided significant reductions in the frequency of migraine days, headache days of at least moderate severity, and migraine- and headache-related disability compared with placebo. Sustained improvements were seen with long-term fremanezumab treatment. Subgroup analyses of participants with difficult-to-treat migraine (those with comorbid depression, overuse of acute headache medications, and concomitant use of other migraine preventive medications) demonstrated the effectiveness of quarterly or monthly fremanezumab in these populations. Ongoing studies are further exploring the potential benefits of fremanezumab in difficult-to-treat migraine and other headache and pain disorders.

Evaluation of the Pharmacokinetic Interaction of Ubrogepant Coadministered With Sumatriptan and of the Safety of Ubrogepant With Triptans

Objective

To evaluate the potential for pharmacokinetic interaction and the safety and tolerability when ubrogepant and sumatriptan are coadministered in a Phase 1 study in healthy participants, and to inform the safety and tolerability of ubrogepant alone and in combination with triptans in Phase 3 trials in participants with migraine.

Background

Calcitonin gene–related peptide is a potent vasodilatory neurotransmitter believed to play a key role in the pathophysiology of migraine. Ubrogepant (UBRELVY™) is a potent and selective antagonist of the human calcitonin gene–related peptide receptor approved for the acute treatment of migraine. Sumatriptan is a serotonin receptor agonist and the most commonly used triptan for the acute treatment of migraine. Ubrogepant could be prescribed with triptans.

Design

The Phase 1 study was a single‐center, open‐label, randomized, 3‐way crossover, single‐dose, pharmacokinetic interaction study, where participants received each of 3 oral treatments with a 7‐day washout period between treatments: single dose of ubrogepant 100 mg, single dose of sumatriptan 100 mg, and ubrogepant 100 mg plus sumatriptan 100 mg. Pharmacokinetic parameters were calculated using a model‐independent approach. The ACHIEVE I and II trials were 2 multicenter, single‐attack, randomized, Phase 3 trials in adults with a history of migraine with or without aura. Participants had the option to take a second dose of study medication or rescue medication to treat a nonresponding migraine or a migraine recurrence from 2 to 48 hours after the initial dose of study medication. Rescue medication options included acetaminophen, nonsteroidal anti‐inflammatory drugs, opioids, anti‐emetics, or triptans. Treatment‐emergent adverse events were evaluated up to 30 days after the last dose in the Phase 1 and Phase 3 studies.

Results

Ubrogepant median time to maximum plasma concentration was delayed (3 hours [range: 1‐5 hours] vs 1.5 hours [range: 1‐4 hours]), mean maximum plasma concentration was reduced by 24% (coefficient of variation: 37.4%) when ubrogepant was coadministered with sumatriptan (n = 29) compared with ubrogepant administered alone (N = 30). No significant effect was observed on the area under the plasma concentration‐time curve of ubrogepant. Sumatriptan area under the curve and maximum plasma concentration showed no significant change when sumatriptan was coadministered with ubrogepant (n = 29), but the sumatriptan time to maximum plasma concentration was delayed (1 hour [range: 0.5‐5 hours] vs 3 hours [range: 0.5‐6 hours]. No treatment‐emergent adverse events were reported with the coadministration of ubrogepant 100 mg and sumatriptan 100 mg in the Phase 1 study. The pooled safety data from ACHIEVE trials (N = 1938) showed similar rates of treatment‐related treatment‐emergent adverse events between participants who took ubrogepant alone and participants who took ubrogepant and a triptan as a rescue medication (14.9% [53/355] vs 12.8% [5/39] in the ubrogepant 100 mg treatment group, respectively).

Conclusions

Although there were slight alterations in ubrogepant pharmacokinetic parameters when coadministered with sumatriptan, such changes are expected to have minimal clinical relevance, especially because no changes were seen in sumatriptan area under the curve and maximum plasma concentration when coadministered with ubrogepant. Coadministration of ubrogepant with sumatriptan was well tolerated in healthy participants in the Phase 1 study, and coadministration of ubrogepant with triptans was well tolerated in participants with migraine in the Phase 3 trials. No new safety concerns for ubrogepant were identified across all trials.

Atogepant Has No Clinically Relevant Effects on the Pharmacokinetics of an Ethinyl Estradiol/Levonorgestrel Oral Contraceptive in Healthy Female Participants

The incidence of migraine is higher among women than men and peaks during the reproductive years, when contraceptive medication use is common. Atogepant, a potent, selective antagonist of the calcitonin gene‒related peptide receptor—in development for migraine prevention—is thus likely to be used by women taking oral contraceptives. This phase 1, open‐label, single‐center, 2‐period, fixed‐sequence study examined the effect of multiple‐dose atogepant 60 mg once daily on the single‐dose pharmacokinetics of a combination oral contraceptive, ethinyl estradiol 0.03 mg and levonorgestrel 0.15 mg (EE/LNG), in healthy postmenopausal or oophorectomized women. For participants in period 1, a single dose of EE/LNG was followed by a 7‐day washout. In period 2, atogepant was given once daily on days 1‐17; an oral dose of EE/LNG was coadministered with atogepant on day 14. Plasma pharmacokinetic parameters for EE and LNG were assessed following administration with and without atogepant. Twenty‐six participants aged 45‐64 years enrolled; 22 completed the study in accordance with the protocol. The area under the concentration‐time curve extrapolated to infinity (AUC_0‐∞) of LNG was increased by 19% when administered with atogepant. Coadministration of atogepant and a single dose of EE/LNG did not substantially alter the pharmacokinetics of EE; the ∼19% increase in plasma AUC_0‐∞ of LNG is not anticipated to be clinically significant. Overall, atogepant alone and in combination with EE/LNG was generally well tolerated, with no new safety signals identified.

Tibetan medicine Ru-yi-Zhen-bao Pills exhibits anti-migraine effect through mediating PAG anti-nociceptive channel

ETHNOPHARMACOLOGICAL RELEVANCE

Migraine is a disabling neurovascular disorder, which increases risk of cardiovascular events and is a social burden worldwide. The present first-line anti-migraine medications can cause overwhelming side-effects, of which one includes the onset of cardiovascular disease. As one of the marketed Tibetan drugs, Ru-yi-Zhen-bao Pills (RYZBP) have been clinically used to treat cardiovascular disorders and as anti-migraine medication. However, there is currently no research exploring the anti-migraine actions of RYZBP.

AIM OF THE STUDY

The current research was designed to assess the anti-migraine roles of RYZBP and explore the underlying mechanisms in a nitroglycerin (NTG)-induced migraine rat model trial.

MATERIALS AND METHODS

120 rats were randomly divided into the following six groups of 20 rats each: normal control group, model control group, positive control group, and RYZBP high/medium/low-dose groups (Ru-yi-Zhen-bao Pills; TH 1.00 g/kg, TM 0.50 g/kg and TL 0.25 g/kg). All rats were administered intragastrically for 7 consecutive days, which were subcutaneously injected with the NTG (10 mg/kg) after the last gavage (except in the normal control group). 3min after NTG treatment, 30 rats (5 rats from each group) were anesthetized and devoted to electroencephalogram(EEG) testing, which was used to evaluate the analgesic effect of RYZBP. One hour after NTG treatment, the rest of the 90 rats (15 rats from each group) were anesthetized and midbrain tissue sample was dissected. The dissection was then washed with physiological saline and collected. The histopathological changes in the periaqueductal gray(PAG) of 5 tissue samples were determined by aematoxylin-eosin (H&E) staining, as well as an estimation of substance P (SP) and neurokinin 1 receptor (NK1R) expression through immunohistochemically staining(IHC). Another 5 midbrain preparations were carried out to evaluate calcitonin gene-related peptide (CGRP), proenkephalin (PENK), SP, and cholecystokinin (CCK) expressions by real-time quantitative polymerase chain reaction (RT-qPCR). The rest of the 5 brainstem tissues were then used to measure CCK, CGRP, and opioid peptide receptor (DORR) levels by western blotting(WB).

RESULTS

In the EEG test, RYZBP (TM 0.50 g / kg) treatment transformed the EEG pain-wave of the NTG-induced migraine model rats in different time period. In the mechanism assay, compared with the model control group, RYZBP pretreatment reduced inflammatory cell infiltration, fibrosis and vacuolation of neuronal cells of PAG tissue seen by HE staining. IHC experiments further showed that RYZBPTM up-regulated SP expression levels and enhanced NK1R levels in the NTG-induced migraine rats (P < 0.05). Therapeutic administration of RYZBP also increased PENK mRNA expression and DORR protein level. Both RT-qPCR and western blotting trials indicated that RYZBP treatment significantly decreased CCK and CGRP expression levels (P < 0.01 or P < 0.05) in the NTG-induced migraine rats.

CONCLUSIONS

RYZBP has the potential to be an effective anti-migraine treatment through suppressing the EEG pain-wave, increasing the levels of SP, PENK, DORR and reducing expression of CCK and CGRP. Mediating the PAG anti-nociceptive channel and inhibiting central sensitization were the two potential mechanisms, which offers further evidence for clinical therapy.

The effect of multiple doses of ubrogepant on the pharmacokinetics of an oral contraceptive in healthy women: Results of an open-label, single-center, two-period, fixed-sequence study

Background:

Ubrogepant is a novel, oral calcitonin gene–related peptide receptor antagonist for acute treatment of migraine. This study evaluated potential drug–drug interactions between ubrogepant and an oral contraceptive containing ethinyl estradiol (EE) and norgestimate (NGM).

Methods:

This open-label, single-center, two-period, fixed-sequence study enrolled healthy, postmenopausal or oophorectomized, adult women. In period 1, participants received a single oral dose of EE 0.035 mg/NGM 0.25 mg (EE-NGM) followed by a 7-day washout. In period 2, participants received oral ubrogepant 50 mg daily on days 1–14; single-dose EE-NGM was coadministered with ubrogepant on day 10. Pharmacokinetic parameters for plasma EE and norelgestromin (NGMN) were compared with and without ubrogepant.

Results:

Twenty-two participants aged 46–66 years were enrolled; 21 completed the study. Geometric mean ratios and 90% confidence intervals for the comparison of EE-NGM + ubrogepant to EE-NGM alone were contained within 0.80 and 1.25 for area under the plasma drug concentration–time curve (AUC) from time zero to infinity (AUC0–∞; 0.96 [0.91, 1.01]) and C max (0.91 [0.82, 1.004]) of NGMN and AUC0–∞ (0.97 [0.93, 1.01]) of EE, but not C max of EE (0.74 [0.69, 0.79]). Median t max of EE was delayed following EE-NGM + ubrogepant (3.0 h) versus EE-NGM alone (median of 1.5 h), whereas median t max of NGMN was unchanged (1.5 h). Geometric mean apparent terminal half-life ( t ½) was similar with and without ubrogepant for EE (23 vs. 21 h) and NGMN (36 h both conditions). All ubrogepant-related adverse events were mild or moderate.

Conclusion:

Ubrogepant did not demonstrate potential for clinically meaningful drug–drug interactions with an EE-NGM oral contraceptive.

Trial registration:

Not applicable (phase 1 trial)

Oxidative Stress Contributes to Hyperalgesia in Osteoporotic Mice

Purpose

Chronic pain is one of the most common complications of postmenopausal osteoporosis. Since oxidative stress is involved in the pathogenesis of postmenopausal osteoporosis, we explored whether oxidative stress contributes to postmenopausal osteoporotic pain.

Methods

Osteoporosis was induced in mice by ovariectomy (OVX). Pain-related behaviours were assessed by measuring sensitivity to mechanical, thermal and cold stimulation. The expression of pain-related transcripts, such acid-sensing ion channel 3 (ASIC3), transient receptor potential vanilloid 1 (TRPV1) and calcitonin gene-related peptide (CGRP), was evaluated. Plasma markers of oxidative stress were also measured. In addition, the effects of the reactive oxygen species scavenger phenyl N-tert-butylnitrone (PBN) on these parameters were assessed.

Results

The OVX mice presented hyperalgesia, as demonstrated by decreased paw withdrawal thresholds to mechanical stimulation and withdrawal latencies to thermal and cold stimulation, along with upregulated expression of ASIC3, TRPV1 and CGRP in the dorsal root ganglia, spinal cord and thalamus tissue. OVX elevated the plasma levels of malondialdehyde (MDA) and advanced oxidation protein products (AOPPs). However, the administration of PBN alleviated these effects.

Conclusion

Our results indicated that oxidative stress contributes to hyperalgesia in OVX mice. Enhanced oxidative stress may be associated with osteoporotic pain. Antioxidant treatment could help alleviate chronic pain in postmenopausal osteoporotic patients.

Safety and tolerability of monthly galcanezumab injections in patients with migraine: integrated results from migraine clinical studies

BACKGROUND

Galcanezumab, a humanized monoclonal antibody that selectively binds to calcitonin gene-related peptide, has demonstrated a significant reduction in monthly migraine headache days in phase 2 and 3 trials. In these analyses, we aimed to evaluate the safety and tolerability of galcanezumab compared with placebo for prevention of episodic or chronic migraine.

METHODS

Data were integrated from three double-blind clinical studies for the up to 6-month galcanezumab exposure group (N = 1435), and from five clinical studies for the up to 1-year all-galcanezumab exposure group (N = 2276). Patients received a monthly 120 mg subcutaneous injection of galcanezumab (with a 240 mg loading dose in month 1), 240 mg galcanezumab, or placebo. Outcomes measured were treatment-emergent adverse events (TEAEs), serious AEs (SAEs), and discontinuation due to AEs (DCAEs). Laboratory results, vital signs, electrocardiogram (ECG), suicidal ideation and behavior results were evaluated.

RESULTS

TEAEs that occurred more frequently in galcanezumab-treated patients included injection site pain, injection site reactions excluding pain, constipation, vertigo, and pruritus. The proportion of DCAEs among galcanezumab-treated patients ranged between 1.8 and 3.0%, and differed from placebo group for galcanezumab 240 mg (P < 0.05). Fewer than 2.0% of patients in either galcanezumab dose-group compared with 1.0% of placebo-treated patients reported a SAE. There were no clinically meaningful differences between galcanezumab and placebo in laboratory measures, vital signs including blood pressure, ECGs, cardiovascular-related AEs, or suicidal ideation and behavior.

CONCLUSIONS

Galcanezumab demonstrated a favorable safety and tolerability profile for up to 1 year of treatment for the prevention of migraine.

TRIAL REGISTRATION

Clinical Trials CGAB = NCT02163993, EVOLVE-1 = NCT02614183, EVOLVE-2 = NCT02614196, REGAIN = NCT02614261, and CGAJ = NCT02614287. All were first posted on 25 November 2015, except CGAB posted on 16 June 2014, and before enrolling the first patient.

Monoclonal antibodies for the prevention of migraine

Introduction: Calcitonin Gene-Related Peptide (CGRP) plays a crucial role in migraine pathophysiology. A novel specific treatment strategy for the prevention of migraine incorporates monoclonal antibodies (mAbs) against CGRP and its canonical receptor. Eptinezumab, fremanezumab and galcanezumab block CGRP mediated effects by binding to the peptide, while erenumab blocks the CGRP receptor.Areas covered: Following a brief overview of pharmacological characteristics, we will review phase III trials for the use of CGRP mAbs in the prevention of episodic and chronic migraine.Expert opinion: All four CGRP mAbs demonstrated an excellent safety, tolerability and efficacy profile in migraine patients. Across all trials mAbs showed superior efficacy for the reduction of monthly migraine days compared to placebo with a net benefit of 2.8 days. Neither cardiovascular nor immunological safety concerns have emerged from clinical trials. Fremanezumab, galcanezumab, and erenumab are approved in the USA and Europe. Based on trial data there is no reason why these mAbs should not become first-line therapies in future. For now, we advocate for the use of mAbs in migraine prevention for patients who failed a minimum of two standard oral treatments based on the novelty and costs of this approach. mAbs are also effective in patients with medication overuse and with comorbid depression or anxiety disorders. Taken together, mAbs are likely to usher in a new era in migraine prevention and provide significant value to patients.

Costs of Acute Headache Medication Use and Productivity Losses Among Patients with Migraine: Insights from Three Randomized Controlled Trials

BACKGROUND

Migraine is associated with a substantial physical and emotional burden for patients. There is also a large economic burden associated with migraine, in terms of lost productivity and healthcare resource use. By reducing the number of monthly migraine days (MMD) experienced by patients, effective preventive treatments can reduce acute medication use and costs of lost productivity.

METHODS

Patient level data from three erenumab clinical trials (NCT02456740, NCT02483585 and NCT02066415) were combined and migraine day frequencies were examined. The number of days per month on which patients used acute medication was estimated as a function of MMD. Productivity losses were estimated based on patient responses to the Migraine Disability Assessment questionnaire. Zero-inflated Poisson regression models were used to predict acute medication use and productivity losses per MMD.

RESULTS

The results demonstrated that as MMD increased, use of acute medication also increased. Similarly, as MMD increased, loss of productivity (due to absenteeism and presenteeism) also increased. The relationship of MMD to both acute headache medication use and lost productivity was non-linear, with marginal outcomes increasing with frequency.

CONCLUSIONS

As MMD increased, acute medication use and productivity loss also increased, but the relationship was non-linear. Therefore, it is important that the distribution of MMD patients is accounted for when estimating the outcomes of migraine patients. By reducing the MMD experienced by patients, effective preventive agents may reduce the requirement for acute medication and also reduce productivity loss, which may translate into potential economic savings.

Fremanezumab for the preventive treatment of migraine

Introduction: The recent approval of monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway introduced the first preventive treatments for migraine that were specifically designed to target the underlying pathophysiology of the disease. Fremanezumab, a fully humanized monoclonal antibody (IgG2Δa) administered via subcutaneous injection, is the first approved monoclonal antibody that targets the CGRP ligand and offers both quarterly (once every 3 months) and monthly dosing. Areas covered: An introduction to migraine, overview of the migraine preventive treatments that target CGRP or its receptor, background on CGRP, and details on the fremanezumab clinical development program in both chronic and episodic migraine. Focus is on the Phase 2b and Phase 3 studies, as well as the recently completed long-term Phase 3 study. Expert opinion: The approval of the first disease-specific preventive treatments for migraine heralds a new era in the treatment of migraine. Fremanezumab has a favorable efficacy and safety profile, which is maintained over the long term. Data from patient subgroups with more-complex disease are promising, and an ongoing study in treatment-refractory patients is evaluating the efficacy of fremanezumab in patients who have failed on multiple prior therapies.

The Role of Anti-calcitonin Gene-related Peptide in Migraine and its Implication in Developing Countries: A Reasonable Option to Consider Despite Higher Cost

Migraine is among the commonest causes of headache in all ages. It is the second most common cause of neurological disability. Currently, antihypertensive, antidepressants and antiepileptic drugs are reasonable preventable medications for chronic migraine. Despite the higher levels of stigma associated with this disease, fewer attempts were made in past regarding the treatment options for chronic migraine. Recently, a novelty treatment was introduced known as calcitonin gene-related peptide (CGRP) monoclonal antibodies as a possible mechanism for the prevention of migraine attacks. CGRP played an important role in the etiology of migraine headaches and was considered as the major peptide behind the cause of the headache disorders. We have reviewed the benefits of these monoclonal antibodies in terms of their efficacy and adverse effects with the available treatment choices. These drugs showed superior results when compared to the placebo and were considered generally safe in the majority of clinical trials. Earlier versions of CGRP antagonists, known as gepants, were less tolerable due to their tendency to cause liver and cardiovascular complications. Thus, in comparison to the earlier gepants, these CGRP monoclonal antibodies were safer and demonstrated excellent tolerability. Short-term side effects were only limited to mild-moderate injection site rash or pruritus, however, their long-term side effects are still unknown. Despite the higher cost of these drugs, we have analyzed the applicability of this drug in the developing countries. Although the quality-adjusted life year (QALY) gained per cost of the drug is still expensive and majority of people may not afford, its excellent tolerability and less adverse effects should also be considered a reason to implement this drug, particularly for resource-limited countries. Moreover, these medications could also become a prototype for future inventions and creations (cost-effective versions for resource-limited countries). In conclusion, this review suggests that CGRP monoclonal antibodies are safer and excellent alternate option for patients with chronic migraine as it has better efficacy, tolerability, and provides a hope to reduce the stigma associated with migraine. All these benefits should be the deciding factors when opting for this treatment and the decision should not be made solely on the socioeconomic status.

Fremanezumab as a preventive treatment for episodic and chronic migraine

Introduction: The importance of calcitonin gene-related peptide (CGRP) in migraine pathogenesis is well established. Fremanezumab is a humanized IgG2a monoclonal antibody that binds to CGRP. Areas covered: In this paper, we review the development of fremanezumab, from early development into approval. The authors focus on the efficacy and safety of fremanezumab in both migraine stages. The authors highlight studies conducted in special populations and focus on unique aspects of its development, as well as on clinical pearls supported by the data. Expert opinion: Fremanezumab was shown to be effective in episodic and chronic migraine, with a monthly and quarterly dose of administration, as monotherapy and add-on therapy. As with other monoclonal antibodies, the anti-CGRP onset of action was remarkably quick, and the effect seems to be maintained over time. No overt safety concerns emerged from the clinical studies, although long-term surveillance is necessary.

Effect of Electroacupuncture on Hyperalgesia and Vasoactive Neurotransmitters in a Rat Model of Conscious Recurrent Migraine

Migraine onset is associated with the abnormal release of vasoactive neurotransmitters from perivascular nerves, and these neurotransmitters are involved in the pathophysiology of migraine. Hyperalgesia is a key feature of migraine, and accumulating evidence indicates that electroacupuncture (EA) at the single acupuncture point (Fengchi [GB20]) is effective in ameliorating hyperalgesia. In clinical practice, multiple acupuncture points are widely used, especially GB20 and Yanglingquan (GB34). However, the role played by vasoactive neurotransmitters in acupuncture antihyperalgesic effect at the single or multiple acupuncture points remains unknown. We aimed to determine whether EA would exert its antihyperalgesic effects by modulating vasoactive neurotransmitter release from the perivascular nerves. Furthermore, we examined whether targeting multiple acupuncture points would be more effective than targeting a single point in reducing hyperalgesia. The mechanical and thermal hyperalgesia were evaluated by measuring the facial and hind-paw mechanical withdrawal thresholds, tail-flick and hot-plate latencies. Plasma concentrations of vasoactive neurotransmitters were determined using rat-specific ELISA kits from jugular vein, including calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), pituitary adenylate cyclase-activating polypeptide (PACAP), nitric oxide (NO), and endothelin-1 (ET-1). The result suggested that EA significantly ameliorated the mechanical and thermal hyperalgesia, reduced c-Fos levels in the trigeminal ganglion, and attenuated plasma and dural levels of vasoactive neurotransmitters, especially in the multiple acupuncture points group (GB20+GB34). In conclusion, EA exerts antihyperalgesic effect in a rat model of conscious recurrent migraine, possibly via modulation of the vasoactive neurotransmitters. Furthermore, targeting multiple acupuncture points is more effective than targeting a single point in reducing hyperalgesia.

Safety and Tolerability of Fremanezumab for the Prevention of Migraine: A Pooled Analysis of Phases 2b and 3 Clinical Trials

OBJECTIVE

Presentation of pooled analysis of safety data for fremanezumab in patients with chronic (CM) or episodic migraine (EM) from 4 placebo-controlled phase 2b and phase 3 studies.

BACKGROUND

There is a need for an effective, safe, and well-tolerated preventive therapy that specifically targets the pathophysiology of migraine to reduce the frequency and severity of migraine attacks in patients with CM or EM who experience 4 or more migraine days per month. Fremanezumab is a fully humanized monoclonal antibody that targets calcitonin gene-related peptide, a neuropeptide involved in the pathophysiology of migraine.

DESIGN/METHODS

The 4 placebo-controlled phases 2b and 3 studies included in this analysis were 16-week, multicenter, randomized, double-blind, placebo-controlled, and parallel-group studies consisting of a screening visit, a 28-day pretreatment baseline period, and a 12-week treatment period with a final evaluation 4 weeks after the final dose of the study drug. Safety endpoints included adverse events (AEs) and immunogenicity.

RESULTS

A total of 2566 patients were randomized across all studies (fremanezumab, n = 1704; placebo, n = 862), and 2563 patients were treated. Common reasons for study discontinuation were withdrawal by patient (n = 78), patient lost to follow-up (n = 60), and AE (n = 50). The mean (standard deviation) duration of exposure was 83.8 (13.6) days for the patients who received fremanezumab, with a total exposure of 390.4 patient years and maximum exposure of 181 days. AEs were mostly mild to moderate in severity and were reported among 48-69% of patients in all treatment groups, and most were injection site reactions (pain, induration, and erythema). Two deaths occurred (chronic obstructive pulmonary disease and intentional overdose of diphenhydramine), both of which were deemed unrelated to study drug by the investigators and sponsor. Cardiovascular adverse events, abnormal liver function tests, and hypersensitivity were uncommon and occurred at similar rates between the placebo and fremanezumab groups.

CONCLUSIONS

Fremanezumab is a generally safe and well-tolerated preventive therapy for migraine in adults.

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

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

CGRP in a gene-environment interaction model for depression: effects of antidepressant treatment

OBJECTIVE

Genetic and environmental factors interact in the development of major depressive disorder (MDD). While neurobiological correlates have only partially been elucidated, altered levels of calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI) in animal models and in the cerebrospinal fluid of depressed patients were reported, suggesting that CGRP may be involved in the pathophysiology and/or be a trait marker of MDD. However, changes in CGRP brain levels resulting from interactions between genetic and environmental risk factors and the response to antidepressant treatment have not been explored.

METHODS

We therefore superimposed maternal separation (MS) onto a genetic rat model (Flinders-sensitive and -resistant lines, FSL/FRL) of depression, treated these rats with antidepressants (escitalopram and nortriptyline) and measured CGRP-LI in selected brain regions.

RESULTS

CGRP was elevated in the frontal cortex, hippocampus and amygdala (but not in the hypothalamus) of FSL rats. However, MS did not significantly alter levels of this peptide. Likewise, there were no significant interactions between the genetic and environmental factors. Most importantly, neither escitalopram nor nortriptyline significantly altered brain CGRP levels.

CONCLUSION

Our data demonstrate that increased brain levels of CGRP are present in a well-established rat model of depression. Given that antidepressants have virtually no effect on the brain level of this peptide, our study indicates that further research is needed to evaluate the functional role of CGRP in the FSL model for depression.

Pharmacokinetics and pharmacodynamics of new acute treatments for migraine

INTRODUCTION

Recommended medications for the acute treatment of migraine encompass triptans, nonsteroidal anti-inflammatory drugs (NSAIDs), and analgesics. While it is true that triptans have been the first successful mechanism-driven treatment in the field, recently, new targets involved in migraine pathogenesis have emerged and new drug classes have been studied for migraine attack therapy. Areas covered: Pharmacodynamics and pharmacokinetics of the new acute treatments of migraine (i.e. ditans, gepants, and glutamate receptor antagonists), considering also marketed drugs in new formulations and administration routes. Expert opinion: Research on the administration routes of marketed drugs was performed in order to improve, in accordance with basic pharmacokinetics parameters, the speed of action of these medications. Similar to the triptans, the new acute treatments are migraine-specific medications, acting on the trigeminovascular system, albeit with different mechanisms. Although available data do not conclusively indicate the superiority of a class over the others, the pharmacodynamics explains the peculiar tolerability and safety profile of different drug classes emerging from clinical trials. Further studies are needed to investigate the possibility of combining different drug classes to optimize the clinical response and the potential role of the novel drugs in medication-overuse headache.

The development of a mouse model of mTBI-induced post-traumatic migraine, and identification of the delta opioid receptor as a novel therapeutic target

BACKGROUND

Post-traumatic headache is the most common and long-lasting impairment observed following mild traumatic brain injury, and frequently has migraine-like characteristics. The mechanisms underlying progression from mild traumatic brain injury to post-traumatic headache are not fully understood. The aim of this study was to develop a mouse model of post-traumatic headache and identify mechanisms and novel targets associated with this disorder.

METHODS

We combined the closed head weight-drop method and the nitroglycerin chronic migraine model. To induce mild traumatic brain injury, a weight was dropped onto intact crania of mildly anesthetized mice, and mechanical responses to chronic-intermittent administration of nitroglycerin, a human migraine trigger, were determined at multiple time points post-injury.

RESULTS

Low dose nitroglycerin (0.1 mg/kg) evoked acute periorbital and hind paw allodynia in both mild traumatic brain injury and sham animals. However, only mild traumatic brain injury mice developed chronic hypersensitivity to low dose nitroglycerin. Migraine medications, sumatriptan and topiramate, inhibited post-traumatic headache-associated allodynia. In addition, the delta opioid receptor agonist, SNC80, also blocked post-traumatic headache-associated allodynia. Finally, we examined the expression of calcitonin gene-related peptide within this model and found that it was increased in trigeminal ganglia two weeks post-mild traumatic brain injury.

CONCLUSIONS

Overall, we have established a mouse model of post-traumatic headache and identified the delta opioid receptor as a novel therapeutic target for this disorder.

CGRP Discovery and Timeline

Calcitonin gene-related peptide (CGRP) was discovered over about 35 years ago through molecular biological techniques. Its activity as a vasodilator and the proposal that it was involved in pain processing were then soon established. Today, we are in the interesting situation of having the approval for the clinical use of antagonists and antibodies that have proved to block CGRP activities and benefit migraine. Despite all, there is still much to learn concerning the relevance of the vasodilator and other activities as well as further potential applications of CGRP agonists and blockers in disease. This review aims to discuss the history and present knowledge and to act as an introductory chapter in this volume.

Association of Serum Levels of Calcitonin Gene-related Peptide and Cytokines during Migraine Attacks

Background:

During a migraine attack, trigeminal activation results in the release of calcitonin gene-related peptide (CGRP), which stimulates the release of inflammatory cytokines playing an important role in migraine.

Objective:

We analyze the relation between CGRP and cytokines during attacks to explore the possible mechanism of migraine.

Materials and Methods:

Migraine patients and healthy control were recruited at the Department of Neurology, the Sixth People's Hospital of Fuyang City, between March 2018 and July 2018. The protein levels of interleukin (IL)-1β, IL-2, IL-6, IL-10, tumor necrosis factor-alpha (TNF-α), and CGRP were determined from the sera of patients with migraine and control subjects by enzyme-linked immunosorbent assay kits. Spearman's rank correlation coefficient was also determined to calculate the correlation between CGRP and inflammatory factors levels.

Results:

The level of IL-1β, IL-6, TNF-α, and CGRP in migraine group were significantly higher than normal group (P < 0.05). The level of CGRP was significantly correlated with IL-1 β (r = 0.30, P < 0.05) and IL-6 (r = 0.94, P < 0.05), but not significantly correlated with IL-2 (r =−0.047, P = 0.75), IL-10 (r = 0.12, P = 0.43), and TNF-α (r = 0.05, P = 0.72).

Conclusions:

In our study, we found migraine patients had a higher IL-6, IL-1β, and TNF level than healthy controls and the level of CGRP was related significantly with the level of IL-1β and IL-6. In conclusion, our results suggest that IL-1β and IL-6 may be involved in the pathogenesis of migraine attacks and CGRP related with the secretion of cytokines.

From LBR-101 to Fremanezumab for Migraine

Calcitonin gene-related peptide (CGRP) is a neuropeptide of importance in migraine pathogenesis. Its central role in migraine was proven pharmacologically by the development of CGRP receptor antagonists. Monoclonal antibodies targeting CGRP or its receptor are effective in the preventive treatment of episodic and chronic migraine and are considered potential breakthroughs in their treatment. Fremanezumab (previously known as TEV-48125, LBR-101, or RN-307) is a humanized IgG2a monoclonal antibody that binds to CGRP. The development of this antibody validated the role of CGRP in chronic migraine and the drug has been recently approved in the US by the FDA, while it continues to be reviewed by other regulatory agencies. Herein we provide an in-depth review of its development. We start by summarizing its in vitro and in vivo pharmacology, and the phase I studies. We then review the late-stage clinical development, with a focus on its efficacy, safety, similarities, and uniqueness relative to other CGRP antibodies. We close by discussing lessons learned on the mechanisms of migraine and areas for future development and exploration.

Erenumab in the treatment of migraine

Migraine is a highly prevalent neurological pain syndrome, and its management is limited due to side effects posed by current preventive therapies. Calcitonin gene-related peptide (CGRP) plays a crucial role in the pathogenesis of migraine. In recent years, research has been dedicated to the development of monoclonal antibodies against CGRP and CGRP receptors for the treatment of migraine. This review will focus on the first US FDA-approved CGRP-receptor monoclonal antibody developed for the prevention of migraine: erenumab. Two Phase II trials (one for episodic migraine and one for chronic migraine) and two Phase III trials for episodic migraine have been published demonstrating the efficacy and safety of erenumab in the prevention of migraine.

Cluster headache beyond the pain phase: A prospective study of 500 attacks

OBJECTIVE

To describe the nature, prevalence, and duration of symptoms in the preictal, ictal, and postictal phases of cluster headache (CH) attacks.

METHODS

Fifty-seven patients with episodic or chronic CH participated in this prospective, observational study. In a questionnaire concerning 33 CH and migraine-related symptoms, patients reported the clinical features of up to 10 CH attacks/patient. The questionnaire was divided into 3 sections: a preictal phase, ictal phase, and postictal phase. For each phase, patients documented whether the given symptom was present, and if possible estimated the duration of the symptom.

RESULTS

In total, 500 CH attack descriptions were obtained. In the preictal phase, general symptoms (most frequently concentration difficulties, restlessness, and mood changes) occurred 20 minutes prior to 46.0% of attacks. Local painful and autonomic symptoms were observed 10 minutes prior to 54.6% and 35% of attacks, respectively. Postictally, pain and autonomic symptoms resolved over 20 minutes, leaving patients with fatigue (36.2%), decreased energy (39.0%), and concentration difficulties (27.6%), lasting a median of 60 minutes.

CONCLUSIONS

Preictal and postictal symptoms are very frequent in CH, demonstrating that CH attacks are not composed of a pain phase alone. Since the origin of CH attacks is unresolved, studies of preictal and postictal symptoms could contribute to the understanding of CH pathophysiology and, potentially, early, abortive treatment strategies.

Chronic and intermittent administration of systemic nitroglycerin in the rat induces an increase in the gene expression of CGRP in central areas: potential contribution to pain processing

Background

Calcitonin gene related peptide (CGRP) is a key neuropeptide involved in the activation of the trigeminovascular system and it is likely related to migraine chronification. Here, we investigated the role of CGRP in an animal model that mimics the chronic migraine condition via repeated and intermittent nitroglycerin (NTG) administration. We also evaluated the modulatory effect of topiramate on this experimental paradigm. Male Sprague-Dawley rats were injected with NTG (5 mg/kg, i.p.) or vehicle, every 2 days over a 9-day period (5 total injections). A group of animals was injected with topiramate (30 mg/kg, i.p.) or saline every day for 9 days. Twenty-four hours after the last administration of NTG or vehicle, animals underwent tail flick test and orofacial Von Frey test. Rats were subsequently sacrificed to evaluate c-Fos and CGRP gene expression in medulla-pons region, cervical spinal cord and trigeminal ganglia.

Results

NTG administration induced spinal hyperalgesia and orofacial allodynia, together with a significant increase in the expression of CGRP and c-Fos genes in trigeminal ganglia and central areas. Topiramate treatment prevented NTG-induced changes by reversing NTG-induced hyperalgesia and allodynia, and inhibiting CGRP and c-Fos gene expression in all areas evaluated.

Conclusions

These findings point to the role of CGRP in the processes underlying migraine chronification and suggest a possible interaction with gamma-aminobutyrate (GABA) and glutamate transmission to induce/maintain central sensitization and to contribute to the dysregulation of descending pain system involved in chronic migraine.

Painful musculosceletal disorders and depression among working aged migraineurs

OBJECTIVE

Musculoskeletal disorders and depression are common among migraineurs. The aim of our study was to evaluate the occurrence of these disorders among working aged migraineurs.

MATERIAL AND METHODS

The risk for fibromyalgia, rheumatoid arthritis (RA), osteoarthrosis (OA), sciatic syndrome, and the occurrence of depression was studied among cases who reported about these conditions and migraine in working aged Finnish population in The Health and Social Support Study (HeSSup) based on postal questionnaire in 2012. Group differences were tested by chi-square test. Odds ratios (ORs with 95% CI) adjusted for age, gender, education level and depression were calculated with logistic regression analysis.

RESULTS

Total of 1505 migraineurs (13%) and 8092 controls were included among the 11 596 responders in 2012. Age and gender adjusted ORs, 2.37 (95% CI 1.81-3.09) for fibromyalgia, 1.46 (1.10-1.95) for RA, 1.58 (1.38-1.80) for OA, and 2.09 (1.84-2.37) for sciatic syndrome, were significant. At least moderate depression was more common among migraineurs (7.3%) than among controls (3.4%) (P < .001).

CONCLUSION

Recognition of comorbid musculoskeletal disorders and mood disorders among migraineurs needs targeted outreach in working aged population. The acute and preventive treatments to control for neuronal sensitization in migraine and comorbid pain disorders may benefit of individual treatment plan and tailored use of antidepressants.