CGRP and migraine from a cardiovascular point of view: what do we expect from blocking CGRP?

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Could erectile dysfunction be a side effect of CGRP inhibition? A case report

Background

Recently, antimigraine drugs targeting the calcitonin gene-related peptide pathway have been approved for clinical use as preventive migraine medication.

Case report

We present a case of a 54-year-old male migraine patient, who reported erectile dysfunction as a possible side effect of treatment with galcanezumab, a monoclonal antibody targeting calcitonin gene-related peptide. His potency recovered after treatment discontinuation.

Discussion

As calcitonin gene-related peptide is involved in mammalian penile erection, erectile dysfunction is a conceivable side effect associated with calcitonin gene-related peptide inhibition. Postmarketing surveillance will elucidate the actual incidence of erectile dysfunction in patients using these new antimigraine drugs, and determine whether a causal relationship between calcitonin gene-related peptide inhibition and erectile dysfunction exists. This would be relevant not only because of the direct sexual consequences of erectile dysfunction, but also considering the potential cardiovascular consequences of calcitonin gene-related peptide (receptor) blockade and the association of both migraine and erectile dysfunction with cardiovascular disease.

Conclusion

Erectile dysfunction might be an overlooked, but reversible side effect in male migraine patients using monoclonal antibodies that inhibit the calcitonin gene-related peptide pathway, including galcanezumab. This paper may raise clinical awareness and suggest that this potential side effect needs to be studied further.

Revised guidelines of the French headache society for the diagnosis and management of migraine in adults. Part 2: Pharmacological treatment

The French Headache Society proposes updated French guidelines for the management of migraine. This article presents the second part of the guidelines, which is focused on the pharmacological treatment of migraine, including both the acute treatment of attacks and the prophylaxis of episodic migraine as well as chronic migraine with and without medication overuse. The specific situations that can be encountered in women with migraine are also discussed, including pregnancy, menstrual migraine, contraception and hormonal replacement therapy.

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

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

Comorbidities of primary headache disorders: a literature review with meta-analysis

Background

Primary headache disorders are common and burdensome conditions. They are associated to several comorbidities, such as cardiovascular or psychiatric ones, which, in turn, contribute to the global burden of headache. The aim of this study is to provide a comprehensive description of the pooled prevalence of comorbidities of primary headache disorders using a meta-analytical approach based on studies published between 2000 and 2020.

Methods

Scopus was searched for primary research (clinical and population studies) in which medical comorbidities were described in adults with primary headache disorders. Comorbidities were extracted using a taxonomy derived from the Global Burden of Disease (GBD) study. We compared prevalence of comorbidities among headache sufferers against general population using GBD-2019 estimates, and compared comorbidities’ proportions in clinical vs. population studies, and by age and gender.

Results

A total of 139 studies reporting information on 4.19 million subjects with primary headaches were included: in total 2.75 million comorbidities were reported (median per subject 0.64, interquartile range 0.32–1.07). The most frequently addressed comorbidities were: depressive disorders, addressed in 51 studies (pooled proportion 23 %, 95 % CI 20–26 %); hypertension, addressed in 48 studies (pooled proportion 24 %, 95 % CI 22–26 %); anxiety disorders addressed in 40 studies (pooled proportion 25 %, 95 % CI 22–28 %). For conditions such as anxiety, depression and back pain, prevalence among headache sufferers was higher than in GBD-2109 estimates. Associations with average age and female prevalence within studies showed that hypertension was more frequent in studies with higher age and less females, whereas fibromyalgia, restless leg syndrome, and depressive disorders were more frequent in studies with younger age and more female.

Conclusions

Some of the most relevant comorbidities of primary headache disorders – back pain, anxiety and depression, diabetes, ischemic heart disease and stroke – are among the most burdensome conditions, together with headache themselves, according to the GBD study. A joint treatment of headaches and of these comorbidities may positively impact on headache sufferers’ health status and contribute to reduce the impact of a group of highly burdensome diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01281-z.

A narrative review of the importance of pharmacokinetics and drug-drug interactions of preventive therapies in migraine management

Objective

To review the pharmacokinetics of major classes of migraine preventives and the clinical implications of drug–drug interactions (DDIs) with the use of these therapies in migraine management.

Background

Preventive treatments for migraine are recommended for a large proportion of patients with frequent migraine attacks. These patients often exhibit a number of comorbidities, which may lead to the introduction of multiple concomitant therapies. Potential DDIs must be considered when using polytherapy to avoid increased risk of adverse events (AEs) or inadequate treatment of comorbid conditions.

Methods

A literature search was performed to identify pharmacokinetic properties and potential DDIs of beta‐blockers, antiepileptic drugs, antidepressants, calcium channel blockers, gepants, and monoclonal antibody therapies targeting the calcitonin gene‐related peptide pathway with medications that may be used for comorbid conditions.

Results

Most DDIs occur through alterations in cytochrome P450 isoenzyme activity and may be complicated by genetic polymorphism for metabolic enzymes. Additionally, drug metabolism may be altered by grapefruit juice ingestion and smoking. The use of migraine preventive therapies may exacerbate symptoms of comorbid conditions or increase the risk of AEs associated with comorbid conditions as a result of DDIs.

Conclusions

DDIs are important to consider in patients with migraine who use multiple medications. The development of migraine‐specific evidence‐based preventive treatments allows for tailored clinical management that reduces the risk of DDIs and associated AEs in patients with comorbidities.

Metabolic Aspects of Migraine: Association With Obesity and Diabetes Mellitus

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

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Pharmacokinetics and safety of ubrogepant when coadministered with calcitonin gene-related peptide-targeted monoclonal antibody migraine preventives in participants with migraine: A randomized phase 1b drug-drug interaction study

Objective

To evaluate the impact of two calcitonin gene–related peptide (CGRP)‐targeted monoclonal antibodies (mAbs), erenumab and galcanezumab, on the pharmacokinetic (PK) profile, safety, and tolerability of ubrogepant.

Background

People taking CGRP‐targeted mAbs for migraine prevention sometimes take ubrogepant, an oral small‐molecule CGRP receptor antagonist, for acute treatment of breakthrough migraine attacks.

Design

In this two‐arm, multicenter, open‐label, phase 1b trial, adults with migraine were randomized to arm 1 (ubrogepant ± erenumab) or arm 2 (ubrogepant ± galcanezumab). The PK profile of ubrogepant was characterized for administration before and 4 days after CGRP‐targeted mAb injection. Participants received single‐dose ubrogepant 100 mg on day 1, subcutaneous erenumab 140 mg (arm 1) or galcanezumab 240 mg (arm 2) on day 8, and ubrogepant 100 mg once daily on days 12–15. In each study arm, serial blood samples were drawn on days 1 and 12 for measurement of plasma ubrogepant concentrations. The primary outcomes were area under the plasma ubrogepant concentration–time curve (AUC) from time 0 to t post‐dose (AUC_0–t) and from time 0 to infinity (AUC_0–inf), and maximum plasma concentration (C_max) of ubrogepant when ubrogepant was administered before or after a single dose of erenumab or galcanezumab. Vital signs and laboratory parameters were monitored.

Results

Forty participants enrolled (20 per arm; mean [standard deviation] ages, 32.2 [8.9] and 38.4 [8.8] years; 50% [10/20] and 60% [12/20] female in arms 1 and 2, respectively). There were no significant differences in ubrogepant C_max after versus before erenumab administration (geometric least‐squares mean [LSM] ratio, 1.04 [90% CI, 0.93–1.16]), and no significant differences in AUC_0–t (1.06 [0.96–1.16]) or AUC_0–inf (1.05 [0.96–1.15]). Similarly, ubrogepant C_max (1.00 [90% CI, 0.82–1.20]), AUC_0–t (1.05 [0.90–1.23]), and AUC_0–inf (1.05 [0.90–1.22]) geometric LSM ratios were statistically equivalent after galcanezumab versus ubrogepant alone. Treatment‐emergent adverse events (TEAEs) were similar to those reported with each treatment alone. No serious TEAEs, TEAEs leading to discontinuation, or clinically relevant changes in laboratory parameters or vital signs were reported.

Conclusions

The PK profile of ubrogepant was not significantly changed and no safety concerns were identified when ubrogepant was coadministered with erenumab or galcanezumab.

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

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

Tolerability of eptinezumab in overweight, obese or type 1 diabetes patients

Introduction

In addition to its role in the pathogenesis of migraine, calcitonin gene-related peptide (CGRP) is implicated in the regulation of insulin secretion. However, there are limited data on the use of CGRP inhibitor monoclonal antibodies in individuals who are overweight/obese and those with diabetes.

Methods

Two randomized, double-blind, placebo-controlled trials were conducted to assess the safety and metabolic effects of eptinezumab in non-migraine overweight/obese patients (study 1) and patients with type 1 diabetes (T1D; study 2). The primary end-point in overweight/obese patients was safety and changes in basal metabolic rate (BMR), defined as the energy expenditure during the fasting and resting states. In patients with T1D, the primary end-points were safety and insulin sensitivity as assessed by the bodyweight and insulin concentration corrected glucose infusion rate (M/I).

Results

A total of 24 patients were enrolled in study 1, and 21 patients were enrolled in study 2. In overweight/obese patients, there was no significant difference in the least squares (LS) mean change in BMR between the eptinezumab- and placebo-treated patients from baseline to day 7 (6.4 vs -25.2 Kcal/day; LS mean difference 31.6 [95% confidence interval -90.6, 153.8]). In patients with T1D, there was no significant difference in insulin sensitivity between the eptinezumab and placebo groups. Eptinezumab was well tolerated in both studies with a similar rate of adverse events between treatment groups, and no new safety signals were identified.

Conclusion

Eptinezumab was well tolerated and not associated with adverse metabolic effects in patients who were overweight/obese or had T1D, providing ongoing support for the use of eptinezumab in these subgroups of patients with migraine.

Evaluating rimegepant for the treatment of migraine

IntroductionCalcitonin gene-related peptide (CGRP) is a vasodilatory neuropeptide involved in the pathophysiology of migraine, a highly disabling neurovascular disorder characterized by severe headache attacks. Rimegepant is a small-molecule CGRP receptor antagonist approved by the FDA for acute treatment of migraine and currently under investigation for migraine prophylaxis. Areas covered The authors summarize available data on safety and tolerability of rimegepant and provide insights on its use for acute migraine treatment. Expert opinion Rimegepant seems to be well tolerated and superior to placebo for two-hour pain freedom. Moreover, rimegepant does not induce vasoconstriction, and is therefore not contraindicated in patients with cardiovascular disease, nor does it seem to induce medication-overuse headache. However, the therapeutic gain of rimegepant is only small, and since CGRP is a vital rescue molecule during ischemia, blocking the CGRP pathway might be detrimental. Although current evidence on CGRP receptor blockade has shown no cardiovascular adverse events, clinicians should remain critical about the use of rimegepant, as well as other CGRP (receptor)-inhibiting drugs. Further research should focus on determining the consequences of long-term CGRP blockade, especially during ischemia or cardiovascular disease, the exact receptors antagonized by rimegepant, and potential effects of combining rimegepant with other antimigraine treatments.

Structural and Functional Brain Changes in Migraine

Migraine is a prevalent primary headache disorder and is usually considered as benign. However, structural and functional changes in the brain of individuals with migraine have been reported. High frequency of white matter abnormalities, silent infarct-like lesions, and volumetric changes in both gray and white matter in individuals with migraine compared to controls have been demonstrated. Functional magnetic resonance imaging (MRI) studies found altered connectivity in both the interictal and ictal phase of migraine. MR spectroscopy and positron emission tomography studies suggest abnormal energy metabolism and mitochondrial dysfunction, as well as other metabolic changes in individuals with migraine. In this review, we provide a brief overview of neuroimaging studies that have helped us to characterize some of these changes and discuss their limitations, including small sample sizes and poorly defined control groups. A better understanding of alterations in the brains of patients with migraine could help not only in the diagnosis but may potentially lead to the optimization of a targeted anti-migraine therapy.

Real-world efficacy, tolerability, and safety of ubrogepant

OBJECTIVE

To assess the real-world efficacy, tolerability, and safety of ubrogepant in a tertiary headache center.

BACKGROUND

The efficacy and safety of ubrogepant for the acute treatment of migraine were established in phase 3 randomized controlled trials. However, there is no real-world data of patient experience with ubrogepant in a population in which the majority of patients have chronic migraine, multiple prior unsuccessful treatments, complex medical comorbidities, and concurrent use of other migraine-specific medications.

METHOD

This was a post-market cohort study conducted at Mayo Clinic Arizona. All patients prescribed ubrogepant were tracked and contacted 1-3 months after the prescription to answer a list of standardized questions. Demographic information and additional headache history were obtained from chart review.

RESULTS

We obtained eligible questionnaire responses from 106 patients. Chronic migraine accounted for 92/106 (86.8%) of the population. Complete headache freedom (from mild/moderate/severe to no pain) and headache relief (from moderate/severe to mild/no pain or mild to no pain) for ≥75% of all treated attacks at 2 hours after taking ubrogepant were achieved in 20/105 (19.0%) and 50/105 (47.6%) patients, respectively. A total of 33/106 (31.1%) patients reported being "very satisfied" with ubrogepant. Adverse events were reported in 42/106 (39.6%) patients, including fatigue in 29/106 (27.4%), dry mouth in 8/106 (7.5%), nausea/vomiting in 7/106 (6.6%), constipation in 5/106 (4.7%), dizziness in 3/106 (2.8%), and other adverse events in 7/106 (6.6%). Predictive factors for being a "good responder" to ubrogepant, defined as headache relief for ≥75% of all treated attacks at 2 hours after taking ubrogepant, included migraine with aura, episodic migraine, <5 prior unsuccessful preventive or acute treatment trials. Additionally, prior treatment responses to a CGRP monoclonal antibody and onabotulinumtoxinA injections are predictive of treatment responses and patient satisfaction to ubrogepant. For the 62/106 (58.5%) patients concurrently using a CGRP monoclonal antibody, there was no difference in the "good responder" rate or adverse event rate compared to those who were not on a CGRP monoclonal antibody, though the rate of moderate, as opposed to mild adverse events was higher, 11/62 (47.8%) versus 3/44 (17.6%), p = 0.048. Additionally, 16 patients had a history of significant cardiovascular or cerebrovascular diseases. No severe adverse events were reported in any patient.

CONCLUSION

Our study confirms and extends the efficacy profile and tolerability of ubrogepant in a real-world tertiary headache clinic and identifies factors that may predict efficacy. Adverse event rates were higher than reported in clinical trials. Further studies are needed to confirm these findings and to evaluate the long-term efficacy and safety of ubrogepant.

Effect of Chinese Medicine Xinmaitong on Blood Pressure in Spontaneously Hypertensive Rats

Objective

To investigate the effect of traditional Chinese antihypertensive compound Xinmaitong on blood pressure and vasoactive factors of vasoconstrictor endothelin-1 (ET-1) and vasodilator calcitonin gene related peptide (CGRP) in spontaneously hypertensive rats (SHRs) with early stage hypertension.

Methods

Twenty male SHRs were randomly divided into two groups: 10 for hypertensive control group and 10 for hypertensive treatment group. In addition, 10 Wistar rats were used as the normal control group without any intervention. SHRs of hypertensive treatment group were orally treated with Xinmaitong, while the hypertensive control group was treated with the normal saline (NS) for a total of eight weeks. The blood pressure in SHRs was examined before and after the end of the eight-week study. After treatment, the rats were killed and the blood samples were collected to measure plasma levels of ET-1 and CGRP by ELISA method, respectively. Meanwhile, the aorta rings were isolated for measuring the mRNA expression of ET-1 and CGRP by PCR. Moreover, the protein levels of ET-1 and CGRP were studied by immunohistochemical.

Results

Daily oral administration of Xinmaitong resulted in significant fall in the SHRs' blood pressure, including systolic and diastolic blood pressures (SBP and DBP), mean blood pressure (MBP), and pulse pressure (PP). The plasma ET-1 levels were reduced and CGRP increased. In parallel, the mRNA and protein expression of ET-1 were decreased, whereas the mRNA and protein expression of CGRP were enhanced in SHRs treated with Xinmaitong.

Conclusion

The present study demonstrated for the first time that Xinmaitong leads to the fall in blood pressure of SHRs and that this antihypertensive effect is, at least in part, due to improvement of arterial tone.

Exogenous CGRP Regulates Apoptosis and Autophagy to Alleviate Traumatic Brain Injury Through Akt/mTOR Signalling Pathway

With millions of traumatic brain injury (TBI) patients every year, TBI is regarded as one of the leading causes of human death and disability. Calcitonin gene-related peptide (CGRP) has been domenstrated to be a potential therapeutic target for TBI. However, the detailed effect and underlying mechanism of CGRP on the injured brain after TBI has hardly been investigated. In this work, we established TBI models of mice and injected CGRP before and after modelling to study its effects on the brain lesion, neurological functions and behaviours, neuron apoptosis and autophagy after TBI. Impacts of introduced CGRP on the activation of Akt/mTOR signalling in the cortical tissues surrounding injured areas after TBI were also evaluated. It was found that CGRP was reduced after TBI, and gradually restored over time. CGRP administration significantly restored the brain lesion induced by TBI. The permeability of blood-brain barrier and brain edema was increased dramatically after TBI, which was ameliorated by exogenous CGRP. Moreover, several neurological behaviour tests were performed, showing that CGRP introduction also relieved the cognitive abilities of mice which were impaired after TBI. Enhancing apoptosis and autophagy of neurons in the cortical tissues of injury sites following TBI were also alleviated by CGRP administration. Besides, CGRP-treated brain cortical tissues showed increased activation of Akt/mTOR signalling after TBI. Therefore, the results suggest that exogenous CGRP plays a neuroprotective role in the injuryed brain after TBI, to relieve cell apoptosis and autophagy, at least partially through Akt/mTOR signalling pathway. This finding also provides more evidence for the treatment of TBI through introducing exogenous CGRP or its related drugs.

Galcanezumab for the prevention of cluster headache

INTRODUCTION

Cluster headache (CH) is among the worst painful conditions. The available therapies are scarce and not specific, leaving many patients unsatisfied because of poor efficacy and/or tolerability. Patients not responding to common treatments are offered semi-invasive and invasive procedures with uncertain results. Based on the current understanding of CH pathophysiology, new possible therapeutic approaches come from drugs interfering with Calcitonin Gene Related Peptide (CGRP).

AREAS COVERED

After summarizing the evidence for CGRP involvement in CH pathophysiology, we review the published literature (PubMed) and information (clinicaltrials.gov, EudraCT, EMA and FDA websites) regarding a novel anti-CGRP monoclonal antibody, Galcanezumab, its pharmacological properties, development, and evidence for the treatment of CH. Publications regarding other indications (migraine) are considered for completeness and safety/tolerability profile.

EXPERT OPINION

In one randomized clinical trial, Galcanezumab has proven to be effective and safe as a preventive treatment in episodic CH, with a favorable tolerability profile offering a potential new option in the therapeutic arsenal. Inefficacy of galcanezumab in chronic CH as well as the inefficacy of another monoclonal antibody against CGRP (fremanezumab) in both episodic and chronic CH question the scalability of the drug in CH management. Further, studies comparing galcanezumab to the current standard treatments are highly desirable.

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

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

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

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

An evidence-based review of CGRP mechanisms in the propagation of chronic visceral pain

Chronic pain is typically defined as pain that persists after acute tissue damage and inflammation or as pain that follows a chronic disease process and lasts more than three months. Because of its debilitating impact on the quality of life of patients, recent research aims to investigate the mechanisms behind nociception to discover novel therapeutic agents to alleviate pain. One such target is the neuropeptide calcitonin gene-related peptide (CGRP), which has shown to play an integral role in migraine pathophysiology. Effective treatments of migraines with CGRP antagonists have stimulated our efforts toward checking a possible involvement of CGRP in nonheadache pain conditions such as hypertension, congestive heart failure, Alzheimer's disease, and vascular ischemia. Here, we provide a brief overview of chronic pain, with a particular emphasis on the role of CGRP as a fundamental mediator of nociceptive pain as well as a target for novel therapeutic agents.

An Evidence-Based Review of Fremanezumab for the Treatment of Migraine

Migraine headache is a common, chronic, debilitating disease with a complex etiology. Current therapy for migraine headache comprises either treatments targeting acute migraine pain or prophylactic therapy aimed at increasing the length of time between migraine episodes. Recent evidence suggests that calcium gene-related peptide (CGRP) is a critical component in the pathogenesis of migraines. Fremanezumab, a monoclonal antibody against CGRP, was recently approved by the Food and Drug Administration (FDA) after multiple studies showed that it was well-tolerated, safe, and effective in the treatment of migraines. Further research is needed to elucidate the long-term effects of fremanezumab and CGRP-antagonists in general, and additional data is required in less healthy patients to estimate its effects in these populations and potentially increase the eligible group of recipients. This is a comprehensive review of the current literature on the efficacy and safety of fremanezumab for the treatment of chronic migraine. In this review we provide an update on the epidemiology, pathogenesis, diagnosis, and current treatment of migraine, and summarize the evidence for fremanezumab as a treatment for migraine.

Potential Drugs Targeting Early Innate Immune Evasion of SARS-Coronavirus 2 via 2'-O-Methylation of Viral RNA

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causing the COVID-19 respiratory disease pandemic utilizes unique 2'-O-methyltransferase (2'-O-MTase) capping machinery to camouflage its RNA from innate immune recognition. The nsp16 catalytic subunit of the 2'-O-MTase is unusual in its requirement for a stimulatory subunit (nsp10) to catalyze the ribose 2'-O-methylation of the viral RNA cap. Here we provide a computational basis for drug repositioning or de novo drug development based on three differential traits of the intermolecular interactions of the SARS-CoV-2-specific nsp16/nsp10 heterodimer, namely: (1) the S-adenosyl-l-methionine-binding pocket of nsp16, (2) the unique "activating surface" between nsp16 and nsp10, and (3) the RNA-binding groove of nsp16. We employed ≈9000 U.S. Food and Drug Administration (FDA)-approved investigational and experimental drugs from the DrugBank repository for docking virtual screening. After molecular dynamics calculations of the stability of the binding modes of high-scoring nsp16/nsp10-drug complexes, we considered their pharmacological overlapping with functional modules of the virus-host interactome that is relevant to the viral lifecycle, and to the clinical features of COVID-19. Some of the predicted drugs (e.g., tegobuvir, sonidegib, siramesine, antrafenine, bemcentinib, itacitinib, or phthalocyanine) might be suitable for repurposing to pharmacologically reactivate innate immune restriction and antagonism of SARS-CoV-2 RNAs lacking 2'-O-methylation.

Galcanezumab in migraine prevention: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Galcanezumab, along with three other monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway, represents the latest disease-specific and mechanism-based treatment for the prophylaxis of migraine. Galcanezumab shares data also for the prophylaxis of cluster headache.

OBJECTIVE

To provide a pooled safety and efficacy analysis of all phase III randomized controlled trials of galcanezumab in the preventive therapy of migraine.

METHODS

A computer-based literature search was conducted on MEDLINE and the US National Institutes of Health Clinical Trials Registry for phase III randomized controlled trials of galcanezumab in migraine prevention. The primary outcome was the mean change in monthly migraine days (MMDs). The proportions of patients who reported at least one adverse event (AE), at least one serious adverse event (SAE) or withdrew from the study were used as safety outcomes.

RESULTS

Two trials were included in the efficacy meta-analysis and three in the safety meta-analysis. Migraine preventive treatment with subcutaneous galcanezumab, at both 120 mg and 240 mg dosages, was associated with a significantly greater reduction in the mean number of MMDs versus placebo (120 mg, MD = -1.98, 95% CI = -2.33 to -1.63; p < 0.0001) or (240 mg, MD = -1.86, 95% CI = -2.20 to -1.53; p < 0.0001). Galcanezumab was found to be more efficacious in all key secondary outcomes as well. Regarding safety, most of the adverse events were mild to moderate, while drop-out rates and serious adverse events were low.

CONCLUSIONS

Galcanezumab is an efficacious and well-tolerated preventive treatment for migraine. Larger clinical trials with longer follow-up periods need to be conducted in order to provide more safety data of the above-mentioned drug.

Efficacy and safety of calcitonin-gene-related peptide binding monoclonal antibodies for the preventive treatment of episodic migraine - an updated systematic review and meta-analysis

BACKGROUND

Migraine is one of the most common neurological disorders that leads to disabilities. However, the conventional drug therapy for migraine might be unsatisfactory at times. Therefore, this meta-analysis aimed to evaluate the efficacy and safety of calcitonin-gene-related peptide binding monoclonal antibody (CGRP mAb) for the preventive treatment of episodic migraine, and provide high-quality clinical evidence for migraine therapy.

METHODS

A systematic electronic database search was conducted to identify the potentially relevant studies. Two independent authors performed data extraction and quality appraisal. Mean difference (MD) and risk ratio (RR) were pooled for continuous and dichotomous data, respectively. The significance levels, weighted effect sizes and homogeneity of variance were calculated.

RESULTS

Eleven high-quality randomized control trials that collectively included 4402 patients were included in this meta-analysis. Compared to placebo group, CGRP mAb therapy resulted in a reduction of monthly migraine days [weighted mean difference (WMD) = - 1.44, 95% CI = (- 1.68,- 1.19)] and acute migraine-specific medication days [WMD = - 1.28, 95% CI = (- 1.66,- 0.90)], with an improvement in 50% responder rate [RR = 1.51, 95% CI = (1.37,1.66)]. In addition, the adverse events (AEs) and treatment withdrawal rates due to AEs were not significantly different between CGRP mAb and placebo groups. Similar efficacy and safety results were obtained for erenumab, fremanezumab, and galcanezumab in subgroup analysis.

CONCLUSIONS

The current body of evidence reveals that CGRP mAb is an effective and safe preventive treatment for episodic migraine.

Neuropathic pain releasing calcitonin gene related peptide protects against stroke in rats

Neuropathic pain (NPP) is deemed as a potential risk of stroke; however, recent pieces of evidence showed that calcitonin gene-related peptide is involving in pain progression as well as organ protection. The mechanisms underlying the neuroprotection of calcitonin gene-related peptide are yet poorly described with respect to stroke. The present study showed that the elevated level of calcitonin gene-related peptide-induced by NPP exerts a protective effect against stroke in rats, which was further confirmed in vivo and vitro via mitigation of inflammatory response, inhibition of neuronal cell apoptosis, and increase in regional cerebral blood flow. Repetitive transcranial magnetic stimulation at trigeminal ganglion was performed to simulate to facilitate the release of calcitonin gene-related peptide for a similar neuroprotective effect. Together, these findings posit that the release of calcitonin gene-related peptide-induced by NPP or repetitive transcranial magnetic stimulation protects against stroke in rats. Thus, repetitive transcranial magnetic stimulation could have high application prospects for the prevention and treatment of stroke.

Characterisation of the calcitonin gene-related peptide receptor antagonists ubrogepant and atogepant in human isolated coronary, cerebral and middle meningeal arteries

BACKGROUND

Migraine has been associated with a dysfunctional activation of the trigeminovascular system. Calcitonin gene-related peptide, a neuropeptide released from the trigeminal nerve fibres, has an important role in the pathophysiology of migraine and is a current therapeutic target for migraine treatment.

METHODS

We examined the effects of two novel calcitonin gene-related peptide receptor antagonists, ubrogepant and atogepant, on the relaxations induced by α calcitonin gene-related peptide in human isolated middle meningeal, cerebral and coronary arteries. Furthermore, the contractile responses to atogepant and ubrogepant per se were studied and compared to the responses elicited by zolmitriptan in proximal and distal human coronary arteries.

RESULTS

In intracranial arteries, both blockers antagonized the calcitonin gene-related peptide-induced relaxations more potently when compared to the inhibition observed in distal human coronary arteries, with atogepant showing a higher potency. When analysing their antagonistic profile in HCA, ubrogepant showed a competitive antagonist profile, while atogepant showed a non-competitive one. Neither of the gepants had vasoconstrictor effect at any of the concentrations studied in human coronary arteries, whereas zolmitriptan elicited concentration-dependent contractions.

CONCLUSION

ubrogepant and atogepant differentially inhibit the calcitonin gene-related peptide-dependent vasodilatory responses in intracranial arteries when compared to distal human coronary arteries. Also, both gepants are devoid of vasoconstrictive properties in human coronary arteries.

Aura and Stroke: relationship and what we have learnt from preclinical models

BACKGROUND

Population-based studies have highlighted a close relationship between migraine and stroke. Migraine, especially with aura, is a risk factor for both ischemic and hemorrhagic stroke. Interestingly, stroke risk is highest for migraineurs who are young and otherwise healthy.

MAIN BODY

Preclinical models have provided us with possible mechanisms to explain the increased vulnerability of migraineurs' brains towards ischemia and suggest a key role for enhanced cerebral excitability and increased incidence of microembolic events. Spreading depolarization (SD), a slowly propagating wave of neuronal depolarization, is the electrophysiologic event underlying migraine aura and a known headache trigger. Increased SD susceptibility has been demonstrated in migraine animal models, including transgenic mice carrying human mutations for the migraine-associated syndrome CADASIL and familial hemiplegic migraine (type 1 and 2). Upon experimentally induced SD, these mice develop aura-like neurological symptoms, akin to patients with the respective mutations. Migraine mutant mice also exhibit an increased frequency of ischemia-triggered SDs upon experimental stroke, associated with accelerated infarct growth and worse outcomes. The severe stroke phenotype can be explained by SD-related downstream events that exacerbate the metabolic mismatch, including pericyte contraction and neuroglial inflammation. Pharmacological suppression of the genetically enhanced SD susceptibility normalizes the stroke phenotype in familial hemiplegic migraine mutant mice. Recent epidemiologic and imaging studies suggest that these preclinical findings can be extrapolated to migraine patients. Migraine patients are at risk for particularly cardioembolic stroke. At the same time, studies suggest an increased incidence of coagulopathy, atrial fibrillation and patent foramen ovale among migraineurs, providing a possible path for microembolic induction of SD and, in rare instances, stroke in hyperexcitable brains. Indeed, recent imaging studies document an accelerated infarct progression with only little potentially salvageable brain tissue in acute stroke patients with a migraine history, suggesting an increased vulnerability towards cerebral ischemia.

CONCLUSION

Preclinical models suggest a key role for enhanced SD susceptibility and microembolization to explain both the occurrence of migraine attacks and the increased stroke risk in migraineurs. Therapeutic targeting of SD and microembolic events, or potential causes thereof, will be promising for treatment of aura and may also prevent ischemic infarction in vulnerable brains.