Pharmacotherapies for Migraine and Translating Evidence From Bench to Bedside

Migraine is a ubiquitous neurologic disorder that afflicts more than 1 billion people worldwide. Recommended therapeutic strategies include the use of acute and, if needed, preventive medications. During the past 2 decades, tremendous progress has been made in better understanding the molecular mechanisms underlying migraine pathogenesis, which in turn has resulted in the advent of novel medications targeting signaling molecule calcitonin gene-related peptide or its receptor. Here, we provide an update on the rational use of pharmacotherapies for migraine to facilitate more informed clinical decision-making. We then discuss the scientific discoveries that led to the advent of new medications targeting calcitonin gene-related peptide signaling. Last, we conclude with recent advances that are being made to identify novel drug targets for migraine.

CGRP monoclonal antibodies and CGRP receptor antagonists (Gepants) in migraine prevention

Migraine is a prevalent and disabling neurological disease. Its preventive treatment for decades has been rather limited due to the absence of disease-specific therapies with limited efficacy and tolerability. The advances made in migraine research have led to the discovery of the calcitonin gene-related peptide (CGRP) and its role in migraine pathophysiology. CGRP is a neuropeptide that acts as potent vasodilator and is involved in pain processing. Increased levels of plasma CGRP have been observed during migraine attacks as well as interictally when comparing patients with migraine and healthy controls. In the last years, two classes of drugs antagonizing CGRP have therefore been developed as the first migraine-specific preventive treatments: anti-CGRP monoclonal antibodies (mAbs) and gepants. Four mAbs have been approved: erenumab, galcanezumab, fremanezumab, and eptinezumab. Gepants are small molecules that antagonize the CGRP receptor; currently only rimegepant and atogepant have been approved for migraine prevention. These new drugs have demonstrated efficacy and safety in clinical trials for both episodic and chronic migraine, and results from their real-world experience are being increasingly reported in literature. In this review, we provide an overview of anti-CGRP drugs and their placement in migraine prevention.

Calcitonin gene-related peptide receptor antagonism reduces motion sickness indicators in mouse migraine models

BACKGROUND

Migraine and vestibular migraine are disorders associated with a heightened motion sensitivity that provoke symptoms of motion-induced nausea and motion sickness. VM affects ∼3% of adults in the USA and affects three-fold more women than men. Triptans (selective serotonin receptor agonists) relieve migraine pain but lack efficacy for vertigo. Murine models of photophobia and allodynia have used injections of calcitonin gene-related peptide (CGRP) or other migraine triggers, such as sodium nitroprusside (SNP), to induce migraine sensitivities in mice to touch and light. Yet, there is limited research on whether these triggers affect motion-induced nausea in mice, and whether migraine blockers can reduce these migraine symptoms. We hypothesized that systemic delivery of CGRP or SNP will increase motion sickness susceptibility and motion-induced nausea in mouse models, and that migraine blockers can block these changes induced by systemically delivered CGRP or SNP.

METHODS

We investigated two measures of motion sickness assessment [motion sickness index (MSI) scoring and motion-induced thermoregulation] after intraperitoneal injections of either CGRP or SNP in C57BL/6J mice. The drugs olcegepant, sumatriptan and rizatriptan were used to assess the efficacy of migraine blockers.

RESULTS

MSI measures were confounded by CGRP's effect on gastric distress. However, analysis of tail vasodilatations as a surrogate for motion-induced nausea was robust for both migraine triggers. Only olcegepant treatment rescued tail vasodilatations.

CONCLUSIONS

These preclinical findings support the use of small molecule CGRP receptor antagonists for the treatment of motion-induced nausea of migraine, and show that triptan therapeutics are ineffective against motion-induced nausea of migraine.Trial Registration: Not Applicable.

New drugs targeting calcitonin gene-related peptide for the management of migraines

INTRODUCTION

Significant advances in migraine research have contributed to the development of new drugs for the treatment of migraine. Monoclonal antibodies (mAbs) against Calcitonin Gene-Related Peptide (CGRP) or its receptor and CGRP receptor antagonists (gepants) have been associated with a good safety profile and resulted in an overall efficacy in reducing the number of monthly migraine days both in episodic and chronic forms of migraine.

AREAS COVERED

The results from main investigation studies (phase 2 or 3) of CGRP-targeting drugs (both anti-CGRP mAbs and gepants) are reported in this expert-opinion review.

EXPERT OPINION

The introduction of new drugs targeting CGRP is a significant breakthrough in the migraine field, and represents a new generation of therapeutic agents that are available to manage migraine. The evaluation of efficacy and safety in the long-term follow-up and the development of trials comparing the available drugs could improve the current knowledge. The economic sustainability of these drugs remains to be clarified, and a cost-cutting campaign should be promoted based on the high burden of migraine.

Pharmaceutical aspects of novel CGRP inhibitors used in the prophylaxis and treatment of migraine

Migraine is one of the most prevalent neurological disorders known to have an immense adverse socio-economic impact. Neurogenic inflammation is thought to mediate migraine, and CGRP is known to be released during acute attacks of migraine that causes vasodilation in extracerebral arteries. Hence, CGRP is believed to play a key role in triggering migraine. Although there are several classes of medications used in the prevention and treatment of migraine pain, targeted therapies are fewer. Therefore, CGRP receptor inhibitors which bind to CGRP receptors in the cranial vasculature have been developed as drugs for migraine therapy. In this review article, we describe the basic pathophysiologic mechanism that causes migraine headaches and the pharmacotherapeutic aspects of CGRP inhibitors available for clinical use. For the purpose of this review, a search was performed on the pharmacological, pharmacokinetic, pharmaceutical, and therapeutic aspects of the FDA-approved CGRP inhibitors viz. erenumab, ubrogepant, rimegepant, atogepant, eptinezumab, fremanezumab, and galcanezumab in UpToDate database and PubMed beginning year 2000. Based on the data collected, a risk-benefit comparison of different classes of novel CGRP inhibitors available for clinical use is provided. This comparative review may help the healthcare providers in choosing the best pharmacotherapeutic agent for their patients based on patient-specific information.

Efficacy and safety of monoclonal antibodies targeting CGRP in migraine prevention. GRADE tables elaborated by the ad hoc working group of the International Headache Society

OBJECTIVES

Grading of Recommendations, Assessment Development and Evaluation (GRADE) tables were created using a standardized and independent assessment of the efficacy and side effects of treatments with monoclonal antibodies (mAb) against calcitonin gene-related peptide (CGRP) or the CGRP receptor for the prevention of migraine. We hope to provide support for author groups writing national or regional treatment or management guidelines for migraine prevention.

METHODS

We formulated patient/population, intervention, comparison and outcomes (PICO) questions for the efficacy and safety of mAb against CGRP or the CGRP-receptor for the prevention of migraine attacks. We performed a systematic literature research for randomized studies with eptinezumab, erenumab, fremanezumab and galcanezumab and a pooled analysis was done, using RevMan 5.4 software. For dichotomous outcomes we used risk ratio, and for continuous outcomes we used the mean difference to compare and summarize the evidence between groups. The evidence across studies, for each outcome, except serious adverse events, was assessed using GRADE evidence tables. Additionally, we report the serious adverse effects in the tables of the characteristics of the studies.

RESULTS

All mAb are superior to placebo for the reduction in monthly migraine days (days in which a headache consistent with migraine occurred) in participants with episodic and chronic migraine. There are no major differences between the mAb.

CONCLUSIONS

The GRADE evidence summary tables provided will support author groups to write treatment guidelines for the prevention of migraine with mAb.

Long-Term Effect of Switching From an Anti-CGRP Receptor to an Anti-CGRP Ligand Antibody in Treatment-Refractory Chronic Migraine: A Prospective Real-World Analysis

In migraine patients with a poor response to a calcitonin gene-related peptide monoclonal antibody against the receptor, switching to a calcitonin gene-related peptide monoclonal antibodies against the ligand may be beneficial. This was a long-term real-world prospective analysis conducted in treatment-refractory chronic migraine patients coming from two large tertiary referral headache centres, who did not achieve a meaningful response to erenumab and were switched to fremanezumab. Responders to fremanezumab were considered those who achieved at least 30% reduction in monthly migraine days by month 3, compared to the post-erenumab baseline. Secondary efficacy and disability outcomes were analysed. Thirty-nine patients (female n = 32, 82.1%; median age: 49 years old, IQR = 29.0-56.0) were included. After three months of treatment with fremanezumab, ten out of 39 patients (25.6%) were considered responders. Four of the 11 patients who continued fremanezumab became responders at month 6, increasing the number of responders to 14 patients (35.9%). Responders received a median of 12 injections (IQR = 9.0-18.0) at the time of the analysis. After the last treatment, 13 patients (33.3%) remained responders. The number of mean monthly migraine days significantly decreased from 21.4 at baseline (IQR = 10.7-30.0) to 8.6 (IQR = 3.8-13.9) at the last follow-up. Painkillers intake and HIT-6 score were significantly reduced at the last follow-up. About 1/3 of patients with treatment refractory chronic migraine who have a disappointing response to erenumab and switch to fremanezumab, obtained a meaningful and sustained improvement of their migraine load over time, supporting the appropriateness of this therapeutic approach in clinical practice.

Novel Migraine Treatments: A Review

Aims: To present a review of the mechanisms of action, available clinical data, and safety profiles of novel migraine therapeutics to inform practice. Methods: PubMed, Medline, and Google Scholar were searched for randomized controlled trials (24 publications), review articles (15 publications), and other pertinent literature (16 publications) discussing the novel migraine therapeutics available between the years 2010 and 2021. All publications were reviewed to assess the mechanism of action, relevant clinical data, and side effect profile for each novel treatment. Therapeutic gain was also recorded in studies that included a placebo arm. Results: A total of 55 studies were included in the final analysis. In the preventive treatment of migraine, novel medications target calcitonin gene-related peptide (CGRP) and fall into either the monoclonal anti-CGRP or gepant class. For the acute treatment of migraine, novel medications fall into either the ditan or gepant class. Several medical devices have been developed for the acute and preventive treatment of migraine. Conclusion: Novel therapeutics are available for both the prevention and acute treatment of migraine headaches. These new medications and neuromodulatory devices appear overall to be safe and effective in the management of migraine headaches.

Patient characteristics and treatment utilization among patients with migraine initiating self-injectable calcitonin gene-related peptide monoclonal antibody and novel acute medication

OBJECTIVE

This study describes patient characteristics and utilization of recently approved novel acute medication and calcitonin gene-related peptide (CGRP) monoclonal antibodies.

METHODS

This retrospective observational study utilized the IBM MarketScan Research Database and Optum's Clinformatics Data Mart from May 2017 through December 2020 (index period). Adult patients initiating self-injectable CGRP monoclonal antibodies (mAbs) (erenumab, fremanezumab, galcanezumab) and novel acute migraine medications (lasmiditan, rimegepant, ubrogepant) with: (a) ≥3 months overlap between the index medication and second medication initiated along with it; (b) ≥1 claim for migraine diagnosis; and (c) continuous medical and pharmacy benefits 12 months pre- and 3 months post-index were included. Data are presented descriptively.

RESULTS

A total of 2840 patients from the MarketScan database and 657 patients from the Optum database were included. Identified patients' (MarketScan/Optum) mean age was 44.7/51.2 years; they were mostly women (88.8%/87.7%); a majority had a chronic migraine diagnosis (64.4%/71.4%) and were prescribed both preventive and acute treatments for migraine in the pre-index period. Most patients received a combination of both preventive and acute medications binding CGRP receptors (43.6%/59.0%) or preventive medication binding CGRP ligands and acute medication binding CGRP receptors (51.9%/34.9%). Mean (SD) number of days of concomitant use of CGRP and novel acute medications were: MarketScan, 29.1 (18.7); Optum, 31.8 (20.4). Prescribing patterns were similar across healthcare provider types within each database.

CONCLUSIONS

Understanding patient characteristics and treatment utilization patterns among patients prescribed both a CGRP mAb and novel acute medication may provide valuable insight regarding migraine treatment selection for healthcare decision makers.

Recent advances in targeting calcitonin gene-related peptide for the treatment of menstrual migraine: A narrative review

Menstrual migraine (MM) has a longer duration and higher drug resistance than non-perimenstrual migraine. Calcitonin gene-related peptide (CGRP) and CGRP receptors are expressed in the peripheral and central nervous systems throughout the trigeminovascular system. The CGRP/CGRP receptor axis plays an important role in sensory physiology and pharmacology. CGRP receptor antagonists and anti-CGRP monoclonal antibodies (mAbs) have shown consistent efficacy and tolerability in the prevention of chronic or episodic migraine and are now approved for clinical use. However, few studies have reported the use of these drugs in MM, and no specific treatment for MM has been approved. This review aimed to shed light on the recent advances in targeting calcitonin gene-related peptides for the treatment of menstrual migraines in PubMed. In this review, we first discuss the axis of the CGRP/CGRP receptor. We then discuss the role of CGRP receptor antagonists and anti-CGRP mAbs in MM treatment. Finally, we discuss the role of the combination of anti-CGRP mAbs and CGRP receptor antagonists in migraine treatment and the drugs that inhibit CGRP release. Altogether, the anti-CGRP mAbs or CGRP receptor antagonists showed good efficacy and safety in the treatment of MM.

The Preclinical Pharmacology of BIBN4096BS, a CGRP Antagonist

CGRP is an important neuropeptide found throughout the cardiovascular system. However, until recently it has been difficult to define its pharmacology or physiological role because of the lack of suitable antagonists. BIBN4096BS is a high-affinity, nonpeptide antagonist that shows much greater selectivity for human CGRP1 receptors compared to any other drug. Its pharmacology has been defined with studies on transfected cells or cell lines endogenously expressing receptors of known composition. These have allowed confirmation that in many human blood vessels, CGRP is working via CGRP1 receptors. However, it also interacts with other CGRP-activated receptors, of unknown composition. In vivo, clinical studies have shown that BIBN4096BS is likely to be useful in the treatment of migraine. It has also been used to define the role of CGRP in phenomena such as plasma extravasation and cardioprotection following ischemia.

BIBN4096BS Antagonizes Human α-calcitonin Gene Related Peptide–induced Headache and Extracerebral Artery Dilatation*

BACKGROUND AND OBJECTIVE

Calcitonin gene-related peptide (CGRP) plays a pivotal role in migraine pathogenesis. BIBN4096BS is the first CGRP receptor antagonist available for human studies, and its efficacy in the acute treatment of migraine has been demonstrated. We investigated the ability of BIBN4096BS to inhibit human alphaCGRP (h-alphaCGRP)-induced headache and cerebral hemodynamic changes in healthy volunteers.

METHODS

Ten healthy volunteers completed this double-blind, placebo-controlled crossover study with 2.5 mg BIBN4096BS and placebo as pretreatments before a 20-minute intravenous infusion of h-alphaCGRP (1.5 microg/min). Transcranial Doppler ultrasonography was used to measure blood flow velocity in the middle cerebral artery (MCA); regional and global cerebral blood flow (CBF) was measured by xenon 133 inhalation single-photon emission computed tomography. The temporal and radial artery diameter was measured by high-frequency ultrasound. Systemic hemodynamics, end-tidal partial pressure of carbon dioxide (PETCO(2)), and headache were monitored.

RESULTS

Of the 10 volunteers, 6 had a CGRP-induced headache during the in-hospital phase after placebo pretreatment but none after BIBN4096BS (P = .031). BIBN4096BS did not affect changes in the diameter of the MCA or changes in CBF induced by h-alphaCGRP. Vasodilatation of the extracranial arteries was, however, significantly inhibited (P < .001 for temporal artery and P = .001 for radial artery).

CONCLUSIONS

These results show that BIBN4096BS effectively prevents CGRP-induced headache and extracerebral vasodilatation but does not significantly affect the induced cerebral hemodynamic changes.

CGRP receptor antagonists: a new choice for acute treatment of migraine?

The neuropeptide calcitonin gene-related peptide (CGRP) is believed to play a central role in the underlying pathology of migraine. Serum levels of CGRP, elevated during a migraine attack, return to normal as pain alleviates. Recently, a causative role for CGRP in migraine has been suggested. Based on these findings, it was proposed that blockade of postsynaptic CGRP receptors, and hence the physiological effects of CGRP, should effectively abort a migraine attack. This review will discuss the therapeutic potential of olcegepant, the first non-peptide CGRP receptor antagonist available for human studies, within the context of current neurovascular theories on migraine pathology.