Targeting CGRP for migraine treatment: mechanisms, antibodies, small molecules, perspectives

Cryo-EM Structure of the Human Amylin 1 Receptor in Complex with CGRP and Gs Protein

Inhibition of calcitonin gene-related peptide (CGRP) or its cognate CGRP receptor (CGRPR) has arisen as a major breakthrough in the treatment of migraine. However, a second CGRP-responsive receptor exists, the amylin (Amy) 1 receptor (AMY1R), yet its involvement in the pathology of migraine is poorly understood. AMY1R and CGRPR are heterodimers consisting of receptor activity-modifying protein 1 (RAMP1) with the calcitonin receptor (CTR) and the calcitonin receptor-like receptor (CLR), respectively. Here, we present the structure of AMY1R in complex with CGRP and Gs protein and compare it with the reported structures of the AMY1R complex with rat amylin (rAmy) and the CGRPR in complex with CGRP. Despite similar protein backbones observed within the receptors and the N- and C-termini of the two peptides bound to the AMY1R complexes, they have distinct organization in the peptide midregions (the bypass motif) that is correlated with differences in the dynamics of the respective receptor extracellular domains. Moreover, divergent conformations of extracellular loop (ECL) 3, intracellular loop (ICL) 2, and ICL3 within the CTR and CLR protomers are evident when comparing the CGRP bound to the CGRPR and AMY1R, which influences the binding mode of CGRP. However, the conserved interactions made by the C-terminus of CGRP to the CGRPR and AMY1R are likely to account for cross-reactivity of nonpeptide CGRPR antagonists observed at AMY1R, which also extends to other clinically used CGRPR blockers, including antibodies.

Menstrually associated migraine

Menstrually related migraine is a disabling condition affecting 35% to 54% females with migraine during their fertile years. The International Headache Classification distinguishes menstrually related migraine from pure menstrual migraine based on the occurrence of the attacks even outside the perimenstrual periods. Hormonal fluctuations are the main driver for the disease in subjects with genetic susceptibility and alterations of brain structures and connectivity. Menstrually related attacks are often particularly severe and disabling requiring proper management. Acute treatment mainly consists of nonsteroidal anti-inflammatory drugs (NSAIDs), recommended in patients also suffering from dysmenorrhea, and triptans. Prevention is specifically indicated in women with high monthly headache frequency or burdensome attacks during perimenstrual periods. Trials proved the efficacy of short-term prevention with triptans and NSAIDs but did not evaluate possible long-term effectiveness and tolerability. Evidence of prevention using hormonal treatments is poor, but extended-cycle treatments might be suitable for women requiring hormonal replacement for concomitant conditions. Few data are available on treatments targeting CGRP, among whom gepants are the most promising because of their utility both in migraine acute and preventive treatment. A greater recognition of disease and a deep knowledge of patients' comorbidities are essential to its proper management.

Supporting the Young Adulthood Transitions in Women With Migraine

Migraine is a painful neurological disorder that disproportionately affects women and has a significant impact on quality of life. This article summarizes the critical role of women's health nurses in supporting young adult women with migraine during major life transitions. Nurses can advocate for workplace or school disability accommodations for women with migraine. Nurses can also support young adult women with migraine by providing education about available treatment that becomes available after an individual's 18th birthday. Women's health nurses can also provide counseling on healthy lifestyle habits to sustain through life transitions, such as guidance on safe alcohol consumption and wellness approaches to migraine management. Through these interventions, women's health nurses can help women with migraine to succeed personally, professionally, and academically while effectively managing migraine symptoms.

Pain persists in mice lacking both Substance P and CGRPα signaling

The neuropeptides Substance P and CGRPα have long been thought important for pain sensation. Both peptides and their receptors are expressed at high levels in pain-responsive neurons from the periphery to the brain making them attractive therapeutic targets. However, drugs targeting these pathways individually did not relieve pain in clinical trials. Since Substance P and CGRPα are extensively co-expressed we hypothesized that their simultaneous inhibition would be required for effective analgesia. We therefore generated Tac1 and Calca double knockout (DKO) mice and assessed their behavior using a wide range of pain-relevant assays. As expected, Substance P and CGRPα peptides were undetectable throughout the nervous system of DKO mice. To our surprise, these animals displayed largely intact responses to mechanical, thermal, chemical, and visceral pain stimuli, as well as itch. Moreover, chronic inflammatory pain and neurogenic inflammation were unaffected by loss of the two peptides. Finally, neuropathic pain evoked by nerve injury or chemotherapy treatment was also preserved in peptide-deficient mice. Thus, our results demonstrate that even in combination, Substance P and CGRPα are not required for the transmission of acute and chronic pain.

OnabotulinumtoxinA: Still the Present for Chronic Migraine

OnabotulinumtoxinA (BT-A) is one of the few drugs approved for the preventive treatment of chronic migraine (CM). Despite this, some aspects of its mechanism of action are still a matter of debate, and the precise magnitude of BT-A effects needs to be completely elucidated. BT-A acts primarily upon trigeminal and cervical nerve endings, by inhibiting the release of inflammatory mediators such as calcitonin gene-related peptide, as well as reducing the insertion of ionotropic and metabotropic receptors into the neuronal membrane. These actions increase the depolarization threshold of trigeminal and cervical nerve fibers, thus reducing their activation. The central actions of BT-A are still a matter of debate: a retrograde axonal transport has been postulated, but not clearly assessed in humans. Clinically, the efficacy of BT-A in CM has been assessed by large, randomized placebo-controlled trials, such as the Phase 3 REsearch Evaluating Migraine Prophylaxis Therapy (PREEMPT) trials. Those results were also confirmed in a wide range of open-label studies, even for long-term periods. Recently, novel findings have led to a better understanding of its pharmacological actions and clinical usefulness in migraine prevention. This narrative review summarizes, updates and critically revises the available data on BT-A and its possible implementation in chronic migraine. Moreover, the current role of BT-A in CM treatment has been discussed.

Rodent behavior following a dural inflammation model with anti-CGRP migraine medication treatment

Background

Migraine is a widespread and prevalent disease with a complex pathophysiology, of which neuroinflammation and increased pain sensitivity have been suggested to be involved. Various studies have investigated the presence of different inflammatory markers in migraineurs and investigated the role of inflammation in inflammatory models with complete Freund's adjuvant (CFA) or inflammatory soup added to the dura mater.

Objective

The aim of the current study was to examine whether application of CFA to the dura mater would cause behavioral alterations that are migraine relevant. In addition, we investigated the potential mitigating effects of fremanezumab, a CGRP (calcitonin gene-related peptide) specific antibody, following CFA application.

Methods

Male Sprague-Dawley rats were randomly divided into six groups: fresh (n = 7), fresh + carprofen (n = 6), fresh + anti-CGRP (n = 6), sham (n = 7), CFA (n = 16), CFA + anti-CGRP (n = 8). CFA was applied for 15 min on a 3 × 3 mm clearing of the skull exposing the dura mater of male Sprague-Dawley rats. We applied the Light/Dark box and Open Field test, combined with the electronic von Frey test to evaluate outcomes. Finally, we observed CGRP immunoreactivity in the trigeminal ganglion.

Results

No differences were observed in the Light/Dark box test. The Open Field test detected behavior differences, notably that sham rats spend less time in the central zone, reared less and groomed more than fresh + carprofen rats. The other groups were not significantly different compared to sham rats, indicating that activation of the TGVS is present in sham surgery and cannot be exacerbated by CFA. However, for the allodynia, we observed specific periorbital sensitization, not observed in the sham animals. This could not be mitigated by fremanezumab, although it clearly reduced the amount of CGRP positive fibers.

Conclusion

CFA surgically administered to the dura causes periorbital allodynia and increases CGRP positive fibers in the trigeminal ganglion. Fremanezumab does not reduce periorbital allodynia even though it reduces CGRP positive fibers in the TG. Further work is needed to investigate whether CFA administered to the dura could be used as a non-CGRP inflammatory migraine model.

Evaluation of serum VIP and aCGRP during pulmonary exacerbation in cystic fibrosis: A longitudinal pilot study of patients undergoing antibiotic therapy

BACKGROUND

Objective monitoring of improvement during treatment of pulmonary exacerbation can be difficulty in children when pulmonary function testing cannot be obtained. Thus, the identification of predictive biomarkers to determine the efficacy of drug treatments is of high priority. The major aim of the current study was to investigate the serum levels of vasoactive intestinal peptide (VIP) and alpha calcitonin gene related peptide (aCGRP) of cystic fibrosis pediatric patients during pulmonary exacerbation and post-antibiotic therapy, and possible associations of their levels with different clinicopathological parameters.

METHODS

21 patients with cystic fibrosis were recruited at onset of pulmonary exacerbation. Serum was collected at time of admission, three days post-antibiotic therapy, and two weeks post-antibiotic therapy (end of antibiotic therapy). Serum VIP and aCGRP levels were measured using ELISA.

RESULTS

Overall least square means of serum aCGRP level but not VIP changed from time of exacerbation to completion of antibiotic therapy (p = 0.005). Serum VIP was significantly associated with the presence of diabetes mellitus (p = 0.026) and other comorbidities (p = 0.013), and with type of antibiotic therapy (p = 0.019). Serum aCGRP level was significantly associated with type of antibiotic therapy (p = 0.012) and positive Staphylococcus aureus microbiology test (p = 0.046).

CONCLUSION

This study could only show significant changes in serum aCGRP levels following treatment of pulmonary exacerbations. Future studies with larger sample size are required to investigate the clinical importance of VIP and aCGRP in cystic fibrosis patients.

Rimegepant, Ubrogepant, and Lasmiditan in the Acute Treatment of Migraine Examining the Benefit-Risk Profile Using Number Needed to Treat/Harm

OBJECTIVES

To develop and compare benefit-risk profiles for rimegepant, ubrogepant, and lasmiditan based on a network meta-analysis (NMA) of published clinical trials.

METHODS

A fixed-effects Bayesian NMA of randomized controlled trials of lasmiditan, rimegepant, and ubrogepant for the acute treatment of adults with migraine were used to determine risk differences for efficacy and safety outcomes of the 3 treatments compared with pooled placebo. Risk differences were used to calculate number needed to treat (NNT) for pain relief and pain freedom at 2 and 2 to 24 hours and freedom from most bothersome symptoms at 2 hours; and number needed to harm (NNH) for dizziness and nausea, relative to placebo.

RESULTS

Results were based on 5 randomized controlled trials (NCT03461757, NCT02828020, NCT02867709, NCT02439320, and NCT02605174). NNT to achieve sustained pain relief at 2 to 24 hours was lowest for rimegepant 75 mg (5; 95% credible interval [Crl]: 4, 7) and ubrogepant 100 mg (5; 95% Crl: 4, 8) and highest for ubrogepant 25 mg (8; 95% Crl: 5, 16). Rimegepant had the lowest NNT to achieve sustained pain freedom at 2 to 24 hours and lasmiditan 50 mg had the highest (7; 95% Crl: 5, 12 vs. 26; 95% Crl: 13, 95). NNH for dizziness and nausea was highest for ubrogepant 25 mg (28; 95% Crl: 15, 62 and 99; 95% Crl: -2580, 2378, respectively). Lasmiditan 200 mg had the lowest NNH for dizziness and rimegepant 75 mg had the lowest NNH for nausea.

CONCLUSIONS

The benefit-risk profiles of lasmiditan, rimegepant, and ubrogepant may improve clinical decision-making.

High-frequency electrical stimulation attenuates neuronal release of inflammatory mediators and ameliorates neuropathic pain

BACKGROUND

Neuroinflammation is an important driver of acute and chronic pain states. Therefore, targeting molecular mediators of neuroinflammation may present an opportunity for developing novel pain therapies. In preclinical models of neuroinflammatory pain, calcitonin gene-related peptide (CGRP), substance P and high mobility group box 1 protein (HMGB1) are molecules synthesized and released by sensory neurons which activate inflammation and pain. High-frequency electrical nerve stimulation (HFES) has achieved clinical success as an analgesic modality, but the underlying mechanism is unknown. Here, we reasoned that HFES inhibits neuroinflammatory mediator release by sensory neurons to reduce pain.

METHODS

Utilizing in vitro and in vivo assays, we assessed the modulating effects of HFES on neuroinflammatory mediator release by activated sensory neurons. Dorsal root ganglia (DRG) neurons harvested from wildtype or transgenic mice expressing channelrhodopsin-2 (ChR2) were cultured on micro-electrode arrays, and effect of HFES on optogenetic- or capsaicin-induced neuroinflammatory mediator release was determined. Additionally, the effects of HFES on local neuroinflammatory mediator release and hyperalgesia was assessed in vivo using optogenetic paw stimulation and the neuropathic pain model of chronic constriction injury (CCI) of the sciatic nerve.

RESULTS

Light- or capsaicin-evoked neuroinflammatory mediator release from cultured transgenic DRG sensory neurons was significantly reduced by concurrent HFES (10 kHz). In agreement with these findings, elevated levels of neuroinflammatory mediators were detected in the affected paw following optogenetic stimulation or CCI and were significantly attenuated using HFES (20.6 kHz for 10 min) delivered once daily for 3 days.

CONCLUSION

These studies reveal a previously unidentified mechanism for the pain-modulating effect of HFES in the setting of acute and chronic nerve injury. The results support the mechanistic insight that HFES may reset sensory neurons into a less pro-inflammatory state via inhibiting the release of neuroinflammatory mediators resulting in reduced inflammation and pain.

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

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

Migraine Prevention with Erenumab: Focus on Patient Selection, Perspectives and Outcomes

Erenumab is a monoclonal antibody targeting the calcitonin gene-related peptide (CGRP) receptor suitable for episodic and chronic migraine prevention. Randomized clinical trials proved the superiority of erenumab to placebo in a strictly selected population, while real-world studies confirmed treatment efficacy in more severe forms of disease – most patients suffered from chronic migraine with medication overuse headache, had prior treatment failures, and long disease duration. According to guidelines, anti-CGRP pathway monoclonal antibodies should be reserved to patients who failed or have contraindication to several classes of preventive treatments. However, their ease of use, tolerability and efficacy make these monoclonal antibodies ideally suitable for most patients with migraine; cost-effectiveness needs to be considered when looking at expanding current prescription criteria. Also, data from open label extensions of randomized control trials confirmed sustained benefits of prolonged treatment up to 5 consecutive years without significant risk of adverse events. Further studies will provide insights on optimal treatment duration to achieve migraine remission and predictors of treatment response. In the present work, we aimed at reviewing design and results of the main studies on erenumab and discussing treatment use in the current migraine prevention scenario; we also summarized the main ongoing research projects and provided clinical perspectives for the future.

Atogepant: an emerging treatment for migraine

INTRODUCTION

Until recently, only nonspecific and not always well-tolerated medications were available for migraine prophylaxis. Currently, specific drugs such as calcitonin gene-related peptide (CGRP) monoclonal antibodies and second-generation gepants are marketed for migraine treatment. Atogepant, an orally active small molecule, is a potent, selective antagonist of the CGRP receptor and is the only gepant authorized exclusively for episodic migraine prophylaxis in adults.

AREAS COVERED

Using literature obtained from PubMed, Scopus, Web of Science, Cochrane, and ClinicalTrials.gov (up to February 13^rd, 2022), the authors summarize and evaluate the available data on atogepant for the prophylaxis of episodic migraine.

EXPERT OPINION

From pivotal trials, the efficacy and tolerability of atogepant in episodic migraine prophylaxis seem comparable to those of CGRP monoclonal antibodies, even if comparative studies have not been conducted. To date, limited information is available on atogepant, including the optimal dose and duration of therapy; hence, it is difficult to establish whether it could be a first-line drug for migraine prophylaxis. Furthermore, it is important to evaluate if atogepant use is associated with the risk of cardiovascular and cerebrovascular events, which could result from potent and persistent blockade of vasodilation by CGRP.

Safety and tolerability of fremanezumab in patients with episodic and chronic migraine: a pooled analysis of phase 3 studies

Background

Fremanezumab, a fully humanized monoclonal antibody that selectively targets calcitonin gene-related peptide, has demonstrated efficacy for preventive treatment of episodic and chronic migraine. Since calcitonin gene-related peptide is expressed within the cardio- and cerebrovascular system and may have cardioprotective effects, it is critical to understand the cardio- and cerebrovascular safety of fremanezumab.

Methods

This was a pooled analysis of three randomized, double-blind, placebo-controlled, phase 3, 12-week trials in which patients with episodic migraine or chronic migraine received quarterly fremanezumab, monthly fremanezumab, or placebo. Incidences of overall and serious adverse events were analyzed. Cardio- and cerebrovascular adverse events (CVAEs) were analyzed in subgroups stratified by cardio- and cerebrovascular medical history, cardiovascular risk factors (CVRFs), and use of cardio- and cerebrovascular medications or triptans.

Results

Two thousand, eight hundred and forty-two patients were included in the study. Overall (58–65%) and serious adverse events (<1–2%) occurred in similar proportions across fremanezumab and placebo groups. CVAEs were infrequent, regardless of cardio- and cerebrovascular medical history (2–6%). CVAEs occurred in low, similar proportions of patients with CVRFs and those using cardio- and cerebrovascular medications or triptans. No cardio- and cerebrovascular signals were identified.

Conclusion

Fremanezumab demonstrated a favorable overall and cardio- and cerebrovascular safety profile in more than 2800 patients with episodic migraine or chronic migraine, regardless of cardio- and cerebrovascular medical history, CVRFs, or medication use.

Trial Registrations: NCT02629861 (HALO EM, https://clinicaltrials.gov/ct2/show/NCT02629861), NCT02621931 (HALO CM, https://clinicaltrials.gov/ct2/show/NCT02621931), NCT03308968 (FOCUS, https://clinicaltrials.gov/ct2/ show/NCT03308968)

Acute Medication Use in Patients With Migraine Treated With Monoclonal Antibodies Acting on the CGRP Pathway: Results From a Multicenter Study and Proposal of a New Index

Introduction

Assessing the impact of migraine preventive treatments on acute medication consumption is important in clinical evaluation. The number of acute medication intakes per each monthly migraine day (MMD) could provide insights on migraine burden and represent a new proxy of treatment effectiveness in clinical trials and real-life studies. We evaluated the effect of monoclonal antibodies acting on calcitonin gene-related peptide (CGRP) pathway on the consumption of migraine acute medication in real-life.

Methods

In two headache centers in Prague (CZ), we included and followed up to 6 months consecutive patients treated with MoAbs acting on CGRP (erenumab or fremanezumab). For each month of treatment, we reported monthly drug intake (MDI) in doses of any medication, migraine-specific (MS), and non-migraine-specific (non-MS) medications, and computed a ratio between MMDs and MDI, i.e., Migraine Medication Index (MMI) for MS and non-MS medications.

Results

We included 90 patients (91.1% women) with a median age of 47 [interquartile range (IQR) 42–51] years; 81 (90.0%) treated with erenumab and 9 (10.0%) with fremanezumab. Median MMDs decreased from 11 (IQR 8–14) at baseline to 4 (IQR 2–5) at Month 3 (p &lt; 0.001 vs. baseline) and 3 (IQR 2–6) at Month 6 (p &lt; 0.001 vs. baseline). Median MDI decreased from 15 drug intakes (IQR 11–20) at baseline to four drug intakes (IQR 2–7) at Month 3 (p &lt; 0.001) and four drug intakes (IQR 2–7) at Month 6 (p &lt; 0.001).The corresponding MDIs for MS medications were 10 (IQR 6–14) at baseline, 3 (IQR 1–5, p &lt; 0.001) at Month 3, and 2 (IQR 0–4, p &lt; 0.001) at Month 6. Monthly drug intakes for non-MS medications were 4 (IQR 0–9) at baseline, 1 (IQR 0–3, p &lt; 0.001) at Month 3 and at Month 6.Median MMI decreased from 1.32 (IQR 1.11–1.68) at baseline to 1.00 (IQR 1.00–1.50, p &lt; 0.001) at Month 3 and 1.00 (IQR 1.00–1.34, p &lt; 0.001) at Month 6.

Conclusions

We confirmed that MoAbs acting on CGRP pathway decrease acute migraine medication consumption. We proposed a new index that can be easily applied in clinical practice to quantify migraine burden and its response to acute medication. Our index could help optimizing migraine acute treatment in clinical practice.

Effectiveness and safety of erenumab and galcanezumab in the prevention of chronic and episodic migraine: A retrospective cohort study

WHAT IS KNOWN AND OBJECTIVE?: Erenumab and galcanezumab have shown great results for migraine prevention. However, strict inclusion criteria, absence of concomitant medication and selective outcome report of clinical trials may sometimes be barely representative of the real-world daily practice. Therefore, this study was designed to evaluate effectiveness and safety of these two monoclonal antibodies targeting calcitonin gene-related peptide in real-world patients. METHODS: This observational, retrospective study evaluated the effectiveness and safety of erenumab 140 mg and galcanezumab 120 mg in 142 real-world patients who had previously not responded to three well-established pharmacological alternatives for migraine prevention. To do so, a combination of objective parameters (monthly headache days and acute migraine-specific medication days) and subjective measurements (Migraine Disability Assessment questionnaire, Headache Impact Test and Visual Analogue Scale), validated for clinical research in migraine, were assessed during clinical interview. RESULTS AND DISCUSSION: Findings here reported show that erenumab and galcanezumab reduced monthly headache days, acute migraine specific medication days per month, Headache Impact Test score, Migraine Disability Assessment Test score and Visual Analogue Scale score after 3 and 6 doses (p < 0.01). Additionally, more than 25% of the patients enrolled in the study experienced a reduction by a half in monthly headache days, and more than 50% of the patients also reported a reduction by a half in the number of migraine specific medication days. Both treatments exhibited a great safety profile, rarely leading to discontinuation because of poor tolerance. WHAT IS NEW AND CONCLUSIONS?: Altogether, these results support previous real-life studies regarding effectiveness and safety and provide an interesting insight in how these preventive therapies are also effective in patients diagnosed with difficult to treat migraine who have previously failed, at least, three different drug classes stablished by current neurology guidelines for migraine prevention. Moreover, these data may suggest that erenumab and galcanezumab are able to not only diminish frequency, but also migraine intensity, and that it should be also considered as an effectiveness measure in line with other authors suggestion.

The efficacy and safety of atogepant for the prophylactic treatment of migraine: evidence from randomized controlled trials

BACKGROUND

Migraine is a common neurovascular disorder that has a severe impact on the individual daily life. Atogepant (AGN-241689) is an orally ingested, small-molecule drugs belonging to calcitonin gene-related peptide receptor antagonist, which has been initiated for the prophylactic treatment of migraine. However, there is no comprehensive literature to study the efficacy and safety of atogepant for the treatment of migraine. In this article, we present a meta-analysis of the available studies.

METHODS

MEDLINE, Embase, Cochrane Library and ClinicalTrials.gov were searched before October 20, 2021 for any relevant literature. Eventually, three randomized clinical trials (RCTs) with 2,466 patients were included in our study.

RESULTS

We pooled 2,466 patients from 3 RCTs and primary outcome was mean monthly migraine days, the secondary endpoints were monthly headache days, acute medication use days per month and ≥ 50% reduction in monthly migraine days, baseline to end of trials. It was found that atogepant (10 mg, 30 mg, 60 mg once a day) led to a significant reduction in monthly migraine days (P < 0.00001, P < 0.00001, P = 0.007), monthly headache days (P < 0.00001, P < 0.00001, P = 0.001), and monthly medication use days (P < 0.00001, P < 0.00001, P = 0.0001), and an increase in the proportion of people with ≥ 50% reduction in monthly migraine days (P = 0.0008, P = 0.02, P = 0.04) in comparison with placebo. Moreover, there were no significant differences (P > 0.05) in outcomes of adverse events between atogepant and placebo.

CONCLUSIONS

Atogepant has shown good efficacy and safety in the prophylactic treatment of migraine, and further studies are expected.

Neurologic Therapeutics in 2035: The Neurology Future Forecasting Series

Therapeutic development has accelerated rapidly in the past 5 years in many neurologic and neurodegenerative diseases. The therapeutic categories of development include small molecules, genetic therapies, and cell-based therapies. Current development has provided novel treatment approaches to disorders without available treatment. However, the regulatory procedures to allow for access to these therapies is challenging, as is the ability to provide wide access to increasingly expensive therapies. By 2035, these challenges are likely to have accelerated and have the potential to create bottlenecks in drug approval and reduced access to patients. Innovative regulatory and payer solutions are required. In addition, ethical considerations around genetic therapies should be considered in current and future development. These approaches will ensure that patients with neurologic disease have broad access to highly innovative therapies.

Hormonal therapies in migraine management: current perspectives on patient selection and risk management

INTRODUCTION

The link between sex hormones and migraines has long been investigated but the mechanisms underlying this altered interaction are not yet fully understood. Herein, we retrace the knowledge on this association in relationship with risk of stroke.

AREAS COVERED

Estrogens fluctuations could trigger migraine attacks and exogenous estrogens intake could be a risk factor for venous thromboembolism (VTE) and stroke. At the same time, ischemic heart diseases and stroke share a common substrate with migraine and other mood disorders, depression, and anxiety.

EXPERT OPINION

The use of hormonal therapies in the context of contraception or replacement therapy must be closely evaluated in a careful risk assessment. We highlight the complex interaction of hormone/neuroinflammation pathways underlying the pathophysiology of migraine glimpsing in mood disorders a possible common denominator of link between hormonal and neuronal systems.

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.

Role of CGRP pathway polymorphisms in migraine: a systematic review and impact on CGRP mAbs migraine therapy

Background

the interest of clinical reaseach in polymorphisms and epigenetics in migraine has been growing over the years. Due to the new era of preventative migraine treatment opened by monoclonal antibodies (mAbs) targeting the signaling of the calcitonin-gene related peptide (CGRP), the present systematic review aims at identifying genetic variants occurring along the CGRP pathway and at verifying whether these can affect the clinical features and the course of disease and the responsiveness of patients to therapy.

Methods

the literature search has been conducted consulting the most relevant scientific databases, i.e. PubMed/MEDLINE, Scopus, Web of Science, the Human Genome Epidemiology (HuGE) Published Literature database (Public Health Genomics Knowledge Base) and Clinicaltrials.gov from database inception until April 1, 2021. The process of identification and selection of the studies included in the analysis has followed the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) criteria for systematic reviews and meta-analyses and the guidance from the Human Genome Epidemiology Network for reporting gene-disease associations.

Results

the search has retrieved 800 results, among which only 7 studies have met the eligibility criteria for inclusion in the analysis. The latter are case-control studies of genetic association and an exploratory analysis and two polymorphisms have been detected as the most recurring: the rs3781719 (T > C) of the CALC A gene encoding CGRP and the rs7590387 of the gene encoding the receptor activity-modifying protein (RAMP) 1 (C > G). Only one study assessing the methylation pattern with regard to CGRP pathway has been found from the search. No genetic association studies investigating the possible effect of genetic variants affecting CGRP signaling on the responsiveness to the most recent pharmacological approaches, i.e. anti-CGRP(R) mAbs, gepants and ditans, have been published. According to the Human Genome Epidemiology (HuGE) systematic reviews and meta-analyses risk-of-bias score for genetic association studies, the heterogeneity between and across studies and the small sample size do not allow to draw conclusions and prompt future studies.

Conclusions

adequately powered, good quality genetic association studies are needed to understand the impact of genetic variants affecting the pathway of CGRP on migraine susceptibility and clinical manifestation and to predict the response to therapy in terms of efficacy and safety.

Comparative efficacy and safety of rimegepant, ubrogepant, and lasmiditan for acute treatment of migraine: a network meta-analysis

OBJECTIVE

In the absence of head-to-head comparisons, the objective of this study was to conduct a network meta-analysis (NMA) to indirectly compare the relative efficacy and safety of rimegepant, ubrogepant, and lasmiditan for the acute treatment of migraine.

METHODS

A systematic literature review was conducted to identify randomized controlled trials (RCTs) of rimegepant, ubrogepant, and lasmiditan in adults with acute migraine. Outcomes included sustained pain freedom and -relief 2-48 hours post-dose, and adverse events. No RCTs were identified that directly compared these interventions. Therefore, a fixed-effects Bayesian NMA was conducted by identifying a connected (via comparison to placebo) network of RCTs.

RESULTS

Five RCTs were identified as follows: rimegepant study 303 (n = 1,466), ubrogepant ACHIEVE I and II (n = 1,672 and n = 1,686, respectively), and lasmiditan SAMURAI and SPARTAN (n = 2,231 and n = 3,005, respectively). Efficacy outcomes (pain freedom and relief at 2, 24, 48 hours) tended to be highest for lasmiditan 200 mg and rimegepant followed lower doses of lasmiditan and all doses of ubrogepant. However, lasmiditan 200 mg was also associated with higher rates of adverse events, particularly somnolence and dizziness.

CONCLUSIONS

Lasmiditan, rimegepant, and ubrogepant all performed significantly better than placebo with respect to pain freedom and pain relief. Efficacy results were similar for rimegepant and lasmiditan with rimegepant having higher rates of pain freedom and relief than lower doses of lasmiditan, while somnolence and dizziness outcomes were lower for rimegepant than higher doses of lasmiditan.

Acute and Preventive Management of Migraine during Menstruation and Menopause

Migraine course is influenced by female reproductive milestones, including menstruation and perimenopause; menstrual migraine (MM) represents a distinct clinical entity. Increased susceptibility to migraine during menstruation and in perimenopause is probably due to fluctuations in estrogen levels. The present review provides suggestions for the treatment of MM and perimenopausal migraine. MM is characterized by long, severe, and poorly treatable headaches, for which the use of long-acting triptans and/or combined treatment with triptans and common analgesics is advisable. Short-term prophylaxis with triptans and/or estrogen treatment is another viable option in women with regular menstrual cycles or treated with combined hormonal contraceptives; conventional prevention may also be considered depending on the attack-related disability and the presence of attacks unrelated to menstruation. In women with perimenopausal migraine, hormonal treatments should aim at avoiding estrogen fluctuations. Future research on migraine treatments will benefit from the ascertainment of the interplay between female sex hormones and the mechanisms of migraine pathogenesis, including the calcitonin gene-related peptide pathway.

Burden and attitude to resistant and refractory migraine: a survey from the European Headache Federation with the endorsement of the European Migraine & Headache Alliance

BACKGROUND

New treatments are currently offering new opportunities and challenges in clinical management and research in the migraine field. There is the need of homogenous criteria to identify candidates for treatment escalation as well as of reliable criteria to identify refractoriness to treatment. To overcome those issues, the European Headache Federation (EHF) issued a Consensus document to propose criteria to approach difficult-to-treat migraine patients in a standardized way. The Consensus proposed well-defined criteria for resistant migraine (i.e., patients who do not respond to some treatment but who have residual therapeutic opportunities) and refractory migraine (i.e., patients who still have debilitating migraine despite maximal treatment efforts). The aim of this study was to better understand the perceived impact of resistant and refractory migraine and the attitude of physicians involved in migraine care toward those conditions.

METHODS

We conducted a web-questionnaire-based cross-sectional international study involving physicians with interest in headache care.

RESULTS

There were 277 questionnaires available for analysis. A relevant proportion of participants reported that patients with resistant and refractory migraine were frequently seen in their clinical practice (49.5% for resistant and 28.9% for refractory migraine); percentages were higher when considering only those working in specialized headache centers (75% and 46% respectively). However, many physicians reported low or moderate confidence in managing resistant (8.1% and 43.3%, respectively) and refractory (20.7% and 48.4%, respectively) migraine patients; confidence in treating resistant and refractory migraine patients was different according to the level of care and to the number of patients visited per week. Patients with resistant and refractory migraine were infrequently referred to more specialized centers (12% and 19%, respectively); also in this case, figures were different according to the level of care.

CONCLUSIONS

This report highlights the clinical relevance of difficult-to-treat migraine and the presence of unmet needs in this field. There is the need of more evidence regarding the management of those patients and clear guidance referring to the organization of care and available opportunities.

Early Management of OnabotulinumtoxinA Treatment in Chronic Migraine: Insights from a Real-Life European Multicenter Study

Introduction

OnabotulinumtoxinA (BT-A) quarterly was the first treatment approved specifically for chronic migraine (CM). It is unclear whether three cycles are better than two to assess early BT-A response.

Methods

We performed a retrospective analysis on real-life prospectively collected data in 16 European headache centers. All the centers provided data on patients treated with BT-A for CM over the first three cycles of treatment. For each treatment cycle we defined patients as “good responders” if reporting a ≥ 50% reduction in monthly headache days compared with the three months before starting BT-A, “partial responders” if reporting a 30–49% reduction in monthly headache days, and “non-responders” if reporting a < 30% reduction in monthly headache days or stopping the treatment before the third cycle.

Results

We included 2879 patients. Seven hundred and eighty-four (64.6%) of the 1213 patients reporting a good response during the first and/or the second cycle had a good response during the third cycle; 309 (49.3%) of the 627 patients reporting a partial response (but no good response) during the first and/or the second cycle had a good response during the third cycle; only 65 (6.3%) of the 1039 patients who did not respond during both the first two cycles achieved a good response during the third cycle. Multivariate analyses showed that partial or good response during the first or the second cycle were independently associated with good response during the third cycle.

Conclusions

Our data suggest that patients with CM responding to BT-A during the first two cycles will likely benefit from the third cycle of treatment, while the probability that non-responders to the first two cycles start responding during the third cycle is low. These results can help guide the individual decision to stop or continue treatment after the second cycle in patients who have not responded to the first two cycles.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40122-021-00253-0.

Menstrual Headache in Women with Chronic Migraine Treated with Erenumab: An Observational Case Series

BACKGROUND

We aimed to assess the differences between menstrual and non-menstrual headache in women with chronic migraine treated with erenumab.

METHODS

We included fertile women from a single center. Patients were defined as responders to erenumab if reporting a ≥50% decrease in monthly headache days, as compared to pre-treatment for more than half of the treatment period. Premenstrual days were defined as the two days preceding menstruation, while menstrual days were defined as the first three days of menstruation.

RESULTS

We included 18 women (11 erenumab responders and 7 erenumab non-responders) contributing to a total of 103 menstrual cycles and 2926 days. The proportion of headache days was higher in menstrual than in premenstrual and non-menstrual days in erenumab responders (34.4% vs. 14.8% vs. 16.3%, respectively; p < 0.001) and in erenumab non-responders (71.4% vs. 53.6% vs. 48.3%, respectively; p < 0.001). Headache days with ≥2 acute medications were higher in menstrual than in premenstrual or non-menstrual headache days in erenumab non-responders (p = 0.002) but not in erenumab responders (p = 0.620).

CONCLUSIONS

Our data suggest that migraine is more frequent during than outside menstrual days even in women treated with erenumab.

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.

Ubrogepant to Treat Acute Migraine in Adults

Migraine is a neurobiological headache disorder that affects around 16% of adults in the United States. Medical treatment of mild to moderate migraines include non-prescription non-steroidal anti-inflammatory drugs, acetaminophen, or aspirin and caffeine-containing combination analgesics. Additionally, moderate to severe migraines and those that are mild to moderate that have not responded to analgesics can be treated with triptans, which are drugs specific for migraine treatment. Non-pharmacological treatments include cognitive behavioral therapy and relaxation training. Medications for the prevention of migraines have also been developed since they are more affective in offsetting the symptoms. Ubrogepant's high specificity and selectivity for calcitonin gene-related peptide (CGRP) sets it apart from certain other drugs, which previously limited the treatment of migraines with or without aura due to their decreased selectivity. The most frequently reported side effects are oropharyngeal pain, nasopharyngitis, and headache. Most studies found that participants receiving Ubrogepant were free from pain within 2 h when compared to placebo. Patients taking Ubrogepant should avoid taking it when pregnant or with end stage renal disease. In summary, Ubrogepant has good tolerability and an overall favorable safety profile. It appears to hold promise for the acute treatment of migraines with or without aura in adults.

Comparative Efficacy of Oral Calcitonin-Gene-Related Peptide Antagonists for the Treatment of Acute Migraine: Updated Meta-analysis

BACKGROUND AND OBJECTIVE

The calcitonin gene-related peptide (CGRP) is a new therapeutic target in migraine-a common disorder resulting in reduced quality of life. The aim of this study was to compare the clinical efficacy of five oral CGRP antagonists with that of a placebo and triptans against acute migraine via meta-analysis.

METHODS

Suitable randomized controlled trials (RCTs) were searched in PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform (WHO-ICTRP) to compare the efficacy of oral CGRP antagonists with that of a placebo and triptans against acute migraine. Review Manager 5.4 was used for data analysis.

RESULTS

A total of 17 trials met the eligibility criteria and were studied in detail. The CGRP antagonists were significantly more effective than the placebo with respect to outcomes such as pain freedom at 2 h post-dose (odds ratio = 2.11; 95% confidence intervals [CIs] = 1.90-2.35) and pain relief at 2 h post-dose (odds ratio = 1.94; 95% CIs = 1.70-2.21). Similar results were found in the subgroup analysis conducted to compare the clinical efficacy of the FDA-approved oral CGRP antagonists (ubrogepant and rimegepant) and placebo. However, the CGRP antagonists were less effective than the triptans with respect to outcomes such as pain freedom at 2 h post-dose (odds ratio = 0.66; 95% CIs = 0.55-0.78) and pain relief at 2 h post-dose (odds ratio = 0.78; 95% CIs = 0.66-0.93).

CONCLUSION

CGRP antagonists are more effective than placebo against acute migraine; however, further studies are required to consider CGRP antagonists as standard first-line treatment for acute migraine instead of triptans, especially in patients with co-existing cardiovascular diseases.

Association between response to triptans and response to erenumab: real-life data

Background

Triptans and erenumab are both migraine-specific agents acting on the calcitonin gene-related peptide pathway. Therefore, response to triptans might be associated with response to erenumab.

Main body

In our study, consecutive patients referring to the Headache Centers of the Abruzzo region from January 2019 to March 2020 and treated with erenumab were interviewed about past use and efficacy of triptans. Triptan users were classified as ‘triptan responders’ if they were headache-free 2 h after treating ≥3 migraine attacks with ≥1 triptan. We considered patients as ‘erenumab responders’, if they had a ≥ 50% mean reduction in monthly migraine days between the 4th and the 6th month from treatment start compared with baseline. Of 91 triptan users, 73 (80.2%) were triptan responders and 58 (63.7%) were erenumab responders. The odds ratio of being erenumab responder was 3.64 (95% CI, 1.25–10.64) for triptan users as compared to non-users. (P = 0.014). Besides, starting erenumab improved triptan response in both erenumab responders and non-responders.

Conclusions

Our data of an association between response to triptans and response to erenumab can be useful for patient advice and to improve the understanding of migraine pathophysiology and treatment.

A Bidirectional View of Migraine and Diet Relationship

Migraine is a common headache with a large negative impact on health. Several endogenous and exogenous factors can influence the severity and frequency of migraine, for example, lifestyle factors including dietary factors. Consequently, lifestyle modifications and dietary considerations have been reported beneficial to moderate clinical features of migraine. Much effort has been invested in determining the lifestyle factors (eg, stress, exercise, sleep, and diet) that trigger migraine to develop recommendations and guidelines for prevention. Diet has also been investigated with a major focus on the content of the diet and to a lesser extent on the amount, pattern, and quality of diet. Identification of dietary factors in migraine has led to nutritional interventions with a major focus on elimination of triggers, and weight control strategies. Several so-called migraine diets have consequently been proposed, for example, the ketogenic diet. Some theories have considered epigenetic diets or functional food to help in altering components of migraine pathogenesis; however, these theories are less investigated. In contrast, evidence is being accumulated to support that some mechanisms underlying migraine may alter dietary choices, for example type, amount, or patterns. Since a causative relationship is not yet established in migraine-diet relationship as to which comes first, this concept is equally valuable and interesting to investigate. Only limited epidemiological data are available to demonstrate that dietary choices are different among patients with migraine compared with individuals without migraine. Differences are reflected on quality, composition, pattern, and the amount of consumption of dietary components. This view emphasizes a potential bidirectional relationship between migraine and diet rather than a one-way influence of one on the other. This targeted review presents examples from current literature on the effects of diet on migraine features and effects of migraine on dietary choices to draw a perspective for future studies.

Conversion from chronic to episodic migraine in patients treated with erenumab: real-life data from an Italian region

BACKGROUND

Most patients treated with erenumab in clinical practice have chronic migraine (CM). We assessed the rate and possible predictors of conversion from CM to episodic migraine (EM) in a real-life study.

MAIN BODY

We performed a subgroup analysis of patients treated with erenumab from January 2019 to February 2020 in the Abruzzo region, central Italy. Treatment was provided according to current clinical practice. For the purpose of the present study, we included patients fulfilling the definition of CM for the three months preceding erenumab treatment and with at least 6 months of follow-up after treatment. We assessed the rate of conversion to EM from baseline to Months 4-6 of treatment and during each month of treatment. To test the clinical validity of conversion to EM, we also assessed the decrease in monthly headache days (MHDs), acute medication days, and median headache intensity on a Numerical Rating Scale (NRS). We included in our study 91 patients with CM. At Months 4-6, 62 patients (68.1%) converted from CM to EM; the proportion of converters increased from Month 1 to Month 5. In the overall group of patients, median MHDs decreased from 26.5 (IQR 20-30) to 7.5 (IQR 5-16; P < 0.001) compared with baseline, while median acute medication days decreased from 21 (IQR 16-30) to 6 (IQR 3-10; P < 0.001) and median NRS scores decreased from 8 (IQR 7-9) to 6 (IQR 4-7; P < 0.001). Significant decreases were found both in converters and in non-converters. We found no significant predictors of conversion to EM among the patients' baseline characteristics.

CONCLUSIONS

In our study, two thirds of patients with CM converted to EM during 6 months of treatment with erenumab. MHDs, acute medication use, and headache intensity decreased regardless of conversion from CM to EM.