The Biology of Monoclonal Antibodies: Focus on Calcitonin Gene-Related Peptide for Prophylactic Migraine Therapy

Voltage-gated Calcium Channels as Potential Therapeutic Targets in Migraine

Migraine is a complex and highly incapacitating neurological disorder that affects around 15% of the general population with greater incidence in women, often at the most productive age of life. Migraine physiopathology is still not fully understood, but it involves multiple mediators and events in the trigeminovascular system and the central nervous system. The identification of calcitonin gene-related peptide as a key mediator in migraine physiopathology has led to the development of effective and highly selective antimigraine therapies. However, this treatment is neither accessible nor effective for all migraine sufferers. Thus, a better understanding of migraine mechanisms and the identification of potential targets are still clearly warranted. Voltage-gated calcium channels (VGCCs) are widely distributed in the trigeminovascular system, and there is accumulating evidence of their contribution to the mechanisms associated with headache pain. Several drugs used in migraine abortive or prophylactic treatment target VGCCs, which probably contributes to their analgesic effect. This review aims to summarize the current evidence of VGGC contribution to migraine physiopathology and to discuss how current pharmacological options for migraine treatment interfere with VGGC function. PERSPECTIVE: Calcitonin gene-related peptide (CGRP) represents a major migraine mediator, but few studies have investigated the relationship between CGRP and VGCCs. CGRP release is calcium channel-dependent and VGGCs are key players in familial migraine. Further studies are needed to determine whether VGCCs are suitable molecular targets for treating migraine.

Effectiveness of Switching CGRP Monoclonal Antibodies in Non-Responder Patients in the UAE: A Retrospective Study

Calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs) have shown promising effectiveness in migraine management compared to other preventative treatment options. Many questions remain regarding switching between antibody classes as a treatment option in patients with migraine headaches. This preliminary retrospective real-world study explored the treatment response of patients who switched between CGRP mAb classes due to lack of efficacy or poor tolerability. A total of 53 patients with migraine headache switched between three of the CGRP mAbs types due to lack of efficacy of the original prescribed CGRP mAbs, specifically eptinezumab, erenumab, and galcanezumab. Fremanezumab was not included due to unavailability in the UAE. Galcanezumab and eptinezumab target the CGRP ligand (CGRP/L), while erenumab targets CGRP receptors (CGRP/R). The analysis of efficacy demonstrated that some improvements were seen in both class switch cohorts (CGRP/R to CGRP/L and CGRP/L to CGRP/R). The safety of switching between CGRP classes was well observed, as any adverse events presented before the class switch did not lead to the discontinuation of treatment following the later switch. The findings of this study suggest that switching between different classes of CGRP mAbs is a potentially safe and clinically viable practice that may have some applications for those experiencing side effects on their current CGRP mAb or those witnessing suboptimal response.

Anti-CGRP antibody galcanezumab modifies the function of the trigeminovascular nocisensor complex in the rat

BACKGROUND

Monoclonal antibodies directed against the neuropeptide calcitonin gene-related peptide (CGRP) are effective in the prevention of chronic and frequent episodic migraine. Since the antibodies do not cross the blood brain barrier, their antinociceptive effect is attributed to effects in meningeal tissues. We aimed to probe if such an antibody can be visualized within the dura mater and the trigeminal ganglia following its administration to rats and to examine if the activity of the trigeminovascular nocisensor complex is influenced by this treatment.

METHODS

Effects of the anti-CGRP antibody galcanezumab on the trigeminovascular nocisensor complex was examined by measuring release of sensory neuropeptides and histamine from the rat dura mater. Deposits of galcanezumab were visualized by fluorescence microscopy in the trigeminal ganglion and the dura mater.

RESULTS

Fluorophore-labelled galcanezumab was detected in the dura mater and the trigeminal ganglion up to 30 days after treatment affirming the long-lasting modulatory effect of this antibody. In female rats, seven days after systemic treatment with galcanezumab the capsaicin-induced release of CGRP was decreased, while that of substance P (SP) was increased in the dura mater. In control rats, release of the inhibitory neuropeptide somatostatin (SOM) was higher in females than in males. Stimulation with high concentration of KCl did not significantly change the release of SOM in control animals, while in rats treated with galcanezumab SOM release was slightly reduced. Galcanezumab treatment also reduced the amount of histamine released from dural mast cells upon stimulation with CGRP, while the effect of compound 48/80 on histamine release was not changed.

CONCLUSIONS

Galcanezumab treatment is followed by multiple changes in the release of neuropeptides and histamine in the trigeminal nocisensor complex, which may contribute to the migraine preventing effect of anti-CGRP antibodies. These changes affecting the communication between the components of the trigeminal nocisensor complex may reduce pain susceptibility in migraine patients treated with CGRP targeting monoclonal antibodies.

Inhibition of Neurogenic Inflammatory Pathways Associated with the Reduction in Discogenic Back Pain

STUDY DESIGN

Retrospective cohort study.

PURPOSE

This study aimed to determine whether the initiation of anti-calcitonin gene-related peptide (CGRP inhibitor) medication therapy for migraines was also associated with improvements in back/neck pain, mobility, and function in a patient population with comorbid degenerative spinal disease and migraine.

OVERVIEW OF LITERATURE

CGRP upregulates pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-6, brain-derived neurotrophic factor, and nerve growth factor in spinal spondylotic disease, which results in disc degeneration and sensitization of nociceptive neurons. Although CGRP inhibitors can quell neurogenic inflammation in migraines, their off-site efficacy as a therapeutic target for discogenic back/neck pain conditions remains unknown.

METHODS

All adult patients diagnosed with spinal spondylosis and migraine treated with CGRP inhibitors at a single academic institution between 2017 and 2020 were retrospectively identified. Patient demographic and medical data, follow-up duration, migraine severity and frequency, spinal pain, functional status, and mobility before and after the administration of CGRP inhibitors were collected. Paired univariate analysis was conducted to determine significant changes in spinal pain, headache severity, and headache frequency before and after the administration of CGRP inhibitors. The correlation between changes in the spinal pain score and functional or mobility improvement was assessed with Spearman's rho.

RESULTS

In total, 56 patients were included. The mean follow-up time after the administration of CGRP inhibitors was 123 days for spinal pain visits and 129 days for migraine visits. Back/neck pain decreased significantly (p <0.001) from 6.30 to 4.36 after starting CGRP inhibitor therapy for migraine control. As recorded in the spine follow-up notes, 25% of patients experienced a functional improvement in the activities of daily living, and 17.5% experienced mobility improvement while taking CGRP inhibitors. Change in back/ neck pain moderately correlated (ρ=-0.430) with functional improvement but was not correlated with mobility improvement (ρ=-0.052).

CONCLUSIONS

Patients taking CGRP inhibitors for chronic migraines with comorbid degenerative spinal conditions experienced significant off-target reduction of back/neck pain.

Galcanezumab in the Treatment of Migraine: A Narrative Review of Real-World Studies

OBJECTIVES

Randomized controlled trials (RCTs) have established the efficacy of galcanezumab, an antibody binding calcitonin gene-related peptide (CGRP) ligand, in the preventive treatment of migraine. The objective was to summarize real-world data evaluating galcanezumab in the preventive treatment of migraine, to complement RCT results with evidence observed in clinical practice.

METHODS

A literature search was conducted to identify real-world studies evaluating galcanezumab in the treatment for patients with migraine.

RESULTS

Twenty-five studies were identified; some only evaluated galcanezumab, and others used pooled data from multiple anti-CGRP antibodies. The studies recruited diverse patient populations, including patients who had failed multiple prior preventive therapies. Treatment was associated with significant reductions from baseline in monthly migraine days and monthly headache days by 4.3 to 12.9 and 3.1 to 13.9, respectively. These values were numerically greater than those reported in most galcanezumab RCTs. Significant decreases from baseline were evident within the first month of treatment, and efficacy was maintained throughout the follow-up periods, ranging from 3 to 12 months. Galcanezumab was also associated with improvements in other efficacy end points, including decreased headache pain intensity, reduction in analgesic use, and improvements in daily functioning and quality of life. Functionality scores, as assessed by the Migraine Disability Assessment Scale questionnaire, decreased by 27 to 75 points from baseline at 3 to 12 months. Galcanezumab was associated with a low discontinuation rate and higher rates of persistence compared with standard migraine preventive treatments.

CONCLUSIONS

The results provide complementary data that galcanezumab is effective across the diverse patient populations observed in routine clinical practice.

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.

Advances in CGRP Monoclonal Antibodies as Migraine Therapy: A Narrative Review

Migraine is a potentially disabling disorder, yet it remains underdiagnosed and undertreated. The release of the neuropeptide calcitonin gene-related peptide (CGRP) in the trigemino-cerebrovascular system plays a vital role in the evolution of migraine. It enhances peripheral sensitization by mediating neurogenic inflammation and also influences central sensitization. The majority of the drug classes available for migraine prophylaxis are nonspecific and associated with numerous side effects and drug interactions. Anti-CGRP monoclonal antibodies (mAb) are an innovative therapeutic class that fulfills the need for more efficacious and tolerable preventive therapy. While erenumab is a mAb to the CGRP receptor, eptinezumab, fremanezumab, and galcanezumab bind to the CGRP molecule. They decrease the number of headache days and improve disability. Upper respiratory tract infection, nausea, constipation, pain at the site of injection, and fatigue are the associated side effects. CGRP mAbs are an excellent advancement in translational research and are a promising addition in migraine therapy. This article discusses the recent advances in the development of the CGRP mAbs.

Comprehensive overview of the venous disorder known as pelvic congestion syndrome

Pelvic venous disorders (PeVD) also known as Pelvic Congestion Syndrome (PCS) affect a great number of women worldwide and often remain undiagnosed. Gynecological symptoms caused by vascular background demand a holistic approach for appropriate diagnosis. This is a relevant cause of chronic pelvic pain and atypical varicose veins. The diagnosis is based on imaging studies and their correlation with clinical presentation. Although the aetiology of PCS still remains unclear, it may result from a combination of factors including genetic predisposition, anatomical abnormalities, hormonal factors, damage to the vein wall, valve dysfunction, reverse blood flow, hypertension and dilatation. The following paper describes an in-depth overview of anatomy, pathophysiology, symptoms, diagnosis and treatment of PCS. In recent years, minimally invasive interventions have become the method of first choice for the treatment of this condition. The efficacy of a percutaneous approach is high and it is rarely associated with serious complications.Key MessagesPelvic venous disorders demand a holistic approach for appropriate diagnosis.This article takes an in-depth look at existing therapies of Pelvic Congestion Syndrome and pathophysiology of this condition.Embolisation is an effective and safe treatment option.

Eptinezumab-jjmr, a humanized monoclonal specific to Calcitonin Gene Related Peptide, for the preventive treatment of migraine in adults

Purpose of Review

Migraines are prevalent and cause significant morbidity, decline in quality of life and healthcare costs universally. Treatment options are varied, but efficacy is limited. This review centers on Eptinezumab-jjmr, a humanized monoclonal specific to CGRP for the prevention of migraines in adults. Herein presented are the science and mechanism of action, indication and clinical evidence for use.

Recent Findings

Migraines are severe, recurrent headaches, which are either episodic or chronic in nature. The pain is severe, often accompanied by co-morbid symptoms, such as photophobia, phonophobia, nausea and emesis, and is limiting in nature. It is a prevalent disorder that causes significant, worldwide disability, morbidity, suffering, and costs.

The pathophysiology of migraines is actively studied, though recent research points to an initiating event causing migraine generation, that is then propagated by other brain regions, a significant one being the trigeminocervical complex. This is driven by biochemical transmitters, chiefly CGRP. This discovery led to the development of CGRP-targeting drugs, including gepants (small molecular antagonists) and anti-CGRP antibodies, such as Eptinezumab-jjmr.

Traditional therapy includes preventative and abortive treatment; however, adherence with preventative treatment has been historically poor, and certain types of abortive therapy carry risks and side effects that preclude them from a large patient population. Moreover, traditional therapy often falls short in migraine therapy. CGRP antagonist, including Eptinezumab, aims to cover the gaps in migraine therapy. We present here evidence to support the safe and effective use of Eptinezumab for the prevention of migraines.

Summary

Migraines are a prevalent primary headache disorder causing significant morbidity worldwide. Traditional abortive and preventative treatments fall short for many patients. Eptinezumab is part of new generation of CGRP-targeting medications and has shown significant evidence to support its use for the prevention of migraines. Further research is required to properly compare eptinezumab with existing pharmacotherapy and update guidelines on the appropriate combinations of therapies that are not available and the correct patient selection for each.

Rimegepant for the treatment of migraine

Migraine is a common form of primary headache, affecting up to 1 in every 6 Americans. The pathophysiology is an intricate interplay of genetic factors and environmental influence and is still being elucidated in ongoing studies. The trigeminovascular system is now known to have a significant role in the initiation of migraines, including the release of pain mediators such as CGRP and substance P. Traditional treatment of migraine is usually divided into acute and preventive treatment. Acute therapy includes non-specific therapy, such as NSAIDs and other analgesics, which may provide relief in mild to moderate migraines. 5-HT1 agonists may provide relief in severe migraine, but are not universally effective and carry a significant side-effect profile with frequent redosing requirement. Prophylactic therapy may reduce the occurrence of acute migraine attacks in selected patients, but does not completely eliminate it. More recently, CGRP antagonism has been studied and shown to be effective in both abortion and prevention of migraine. Novel medications, targeting CGRP, divide into CGRP antibodies and receptor antagonists (gepants). Rimegepant, a second-generation gepant, has shown efficacy in several clinical trials in treating acute migraine. Ongoing trials are also evaluating its role in migraine prophylaxis, and results are promising. It is also generally safer for use than existing options, does not appear to increase the chance of developing chronic migraines, and carries a very tolerable side effects profile. It is a part of a growing arsenal in migraine treatment, and may present the silver bullet for treatment of this disease.

A Comprehensive Review of Zavegepant as Abortive Treatment for Migraine

Migraine headache is a widespread and complex neurobiological disorder that is characterized by unilateral headaches that are often accompanied by photophobia and phonophobia. Migraine is one of the leading chief complaints in the emergency department with negative impacts on quality of life and activities of daily living. The high number of emergency presentations also results in a significant economic burden. Its risk factors include family history, genetics, sex, race, socioeconomics, the existence of comorbid conditions, and level of education. Triggers include stress, light, noise, menstruation, weather, changes in sleep pattern, hunger, dehydration, dietary factors, odors, and alcohol. The International Headache Society has defined criteria for the diagnosis of migraine with and without aura. The pathophysiology of migraine headaches is multifactorial so there are a variety of treatment approaches. The current treatment approach includes abortive medications and prophylactic medications. Abortive medications include the first-line treatment of triptans, followed by ergot alkaloids, and calcitonin gene-related peptide (CGRP) receptor antagonists along with supplemental caffeine and antiemetics. Trigeminal afferents from the trigeminal ganglion innervate most cranial tissues and many areas of the head and face. These trigeminal afferents express certain biomarkers such as calcitonin gene-related peptide (CGRP), substance P, neurokinin A, and pituitary adenylate cyclase-activating polypeptide that are important to the pain and sensory aspect of migraines. In this comprehensive review, we discuss Zavegepant, a calcitonin gene-related peptide receptor antagonist, as a new abortive medication for migraine headaches.

Measuring dose-related efficacy of eptinezumab for migraine prevention: post hoc analysis of PROMISE-1 and PROMISE-2

Background

Eptinezumab 100 mg and 300 mg met the primary efficacy endpoint in both PROMISE clinical trials, significantly reducing frequency of monthly migraine days over Weeks 1‒12. The objective of this analysis was to assess the clinical response to eptinezumab 100 mg and 300 mg within the pivotal phase 3 PROMISE-1 and PROMISE-2 studies to potentially identify subsets of patients with meaningful differences between doses.

Methods

Patients from PROMISE-1 (NCT02559895) and PROMISE-2 (NCT02974153) trials were divided into subgroups based on demographic and migraine characteristics, and baseline questionnaire responses. For each subgroup, the overall likelihood of achieving ≥ 50% migraine responder rate (MRR) over Weeks 1–12 and Weeks 13–24 with either eptinezumab 100 mg or 300 mg was calculated using odds ratios (with associated confidence intervals) and compared.

Results

In PROMISE-1 (episodic migraine) and PROMISE-2 (chronic migraine), the likelihood of achieving ≥ 50% MRR over Weeks 1–12 and Weeks 13–24 was roughly equivalent for patients receiving either dose level of eptinezumab. Given the number of comparisons performed, sporadic apparent differences were seen but no replicated patterns between studies emerged. In PROMISE-1, no differences were observed in any subgroup over Weeks 1–12. In PROMISE-2, patients reporting < 15 monthly migraine days at baseline, any problems with mobility per the EQ-5D-5L, or a social functioning score > 45.0 per the 36-item Short-Form Health Survey (SF-36), appeared more likely to achieve ≥ 50% MRR with 300 mg over Weeks 1–12, with none of these being apparent in PROMISE-1.

Conclusions

Overall, these data suggest that across PROMISE-1 and PROMISE-2, there were no meaningful differences in the likelihood of achieving ≥ 50% MRR between the eptinezumab dose levels in the majority of patient subgroups. In the few subgroups that displayed small, but potentially meaningful differences, patients were more likely to achieve ≥ 50% MRR with eptinezumab 300 mg; however, minimal consistency across both studies and time periods was noted.

Trial Registration

ClinicalTrials.gov.

PROMISE-1: NCT02559895.

PROMISE-2: NCT02974153.

Constipation Caused by Anti-calcitonin Gene-Related Peptide Migraine Therapeutics Explained by Antagonism of Calcitonin Gene-Related Peptide's Motor-Stimulating and Prosecretory Function in the Intestine

The development of small-molecule calcitonin gene-related peptide (CGRP) receptor antagonists (gepants) and of monoclonal antibodies targeting the CGRP system has been a major advance in the management of migraine. In the randomized controlled trials before regulatory approval, the safety of these anti-CGRP migraine therapeutics was considered favorable and to stay within the expected profile. Post-approval real-world surveys reveal, however, constipation to be a major adverse event which may affect more than 50% of patients treated with erenumab (an antibody targeting the CGRP receptor), fremanezumab or galcanezumab (antibodies targeting CGRP). In this review article we address the question whether constipation caused by inhibition of CGRP signaling can be mechanistically deduced from the known pharmacological actions and pathophysiological implications of CGRP in the digestive tract. CGRP in the gut is expressed by two distinct neuronal populations: extrinsic primary afferent nerve fibers and distinct neurons of the intrinsic enteric nervous system. In particular, CGRP is a major messenger of enteric sensory neurons which in response to mucosal stimulation activate both ascending excitatory and descending inhibitory neuronal pathways that enable propulsive (peristaltic) motor activity to take place. In addition, CGRP is able to stimulate ion and water secretion into the intestinal lumen. The motor-stimulating and prosecretory actions of CGRP combine in accelerating intestinal transit, an activity profile that has been confirmed by the ability of CGRP to induce diarrhea in mice, dogs and humans. We therefore conclude that the constipation elicited by antibodies targeting CGRP or its receptor results from interference with the physiological function of CGRP in the small and large intestine in which it contributes to the maintenance of peristaltic motor activity, ion and water secretion and intestinal transit.

The locus of Action of CGRPergic Monoclonal Antibodies Against Migraine: Peripheral Over Central Mechanisms

Migraine is a complex neurovascular disorder characterized by attacks of moderate to severe unilateral headache, accompanied by photophobia among other neurological signs. Although an arsenal of antimigraine agents is currently available in the market, not all patients respond to them. As Calcitonin Gene-Related Peptide (CGRP) plays a key role in the pathophysiology of migraine, CGRP receptor antagonists (gepants) have been developed. Unfortunately, further pharmaceutical development (for olcegepant and telcagepant) was interrupted due to pharmacokinetic issues observed during the Randomized Clinical Trials (RCT). On this basis, the use of monoclonal antibodies (mAbs; immunoglobulins) against CGRP or its receptor has recently emerged as a novel pharmacotherapy to treat migraines. RCT showed that these mAbs are effective against migraines producing fewer adverse events. Presently, the U.S. Food and Drug Administration approved four mAbs, namely: (i) erenumab; (ii) fremanezumab; (iii) galcanezumab; and (iv) eptinezumab. In general, specific antimigraine compounds exert their action in the trigeminovascular system, but the locus of action (peripheral vs. central) of the mAbs remains elusive. Since these mAbs have a molecular weight of ∼150 kDa, some studies rule out the relevance of their central actions as they seem unlikely to cross the Blood-Brain Barrier (BBB). Considering the therapeutic relevance of this new class of antimigraine compounds, the present review has attempted to summarize and discuss the current evidence on the probable sites of action of these mAbs.

Chronic Migraine Pathophysiology and Treatment: A Review of Current Perspectives

Chronic migraine is a disabling neurological disorder that imposes a considerable burden on individual and socioeconomic outcomes. Chronic migraine is defined as headaches occurring on at least 15 days per month with at least eight of these fulfilling the criteria for migraine. Chronic migraine typically evolves from episodic migraine as a result of increasing attack frequency and/or several other risk factors that have been implicated with migraine chronification. Despite this evolution, chronic migraine likely develops into its own distinct clinical entity, with unique features and pathophysiology separating it from episodic migraine. Furthermore, chronic migraine is characterized with higher disability and incidence of comorbidities in comparison to episodic migraine. While existing migraine studies primarily focus on episodic migraine, less is known about chronic migraine pathophysiology. Mounting evidence on aberrant alterations suggest that pronounced functional and structural brain changes, central sensitization and neuroinflammation may underlie chronic migraine mechanisms. Current treatment options for chronic migraine include risk factor modification, acute and prophylactic therapies, evidence-based treatments such as onabotulinumtoxinA, topiramate and newly approved calcitonin gene-related peptide or receptor targeted monoclonal antibodies. Unfortunately, treatments are still predominantly ineffective in aborting migraine attacks and decreasing intensity and frequency, and poor adherence and compliance with preventative medications remains a significant challenge. Novel emerging chronic migraine treatments such as neuromodulation offer promising therapeutic approaches that warrant further investigation. The aim of this narrative review is to provide an update of current knowledge and perspectives regarding chronic migraine background, pathophysiology, current and emerging treatment options with the intention of facilitating future research into this debilitating and largely indeterminant disorder.

Safety and tolerability of preventive treatment options for chronic migraine

INTRODUCTION

Relative to migraine generally, chronic migraine (CM) imposes greater disability, healthcare utilization and socioeconomic burden. Six therapies currently possess a credible evidence base for prevention/suppression of CM. This review is intended to provide an assessment of their relative utility, defined as a blend of safety, tolerability and efficacy, focusing in particular on their safety and tolerability.Areas Covered: We discuss all six medications currently FDA-approved for migraine prevention which also specifically possess credible evidence of efficacy in treating CM. While we do address the efficacy of each, our primary emphasis involves assessment of safety and tolerability data derived from clinical trials and post-marketing experience.Expert Opinion: Recent research involving CM has led to the identification of highly targeted and typically well-tolerated therapies. For patients who experience obstacles to accessing these newer therapies, topiramate is available as an evidence-based alternative, but contraindications, drug-drug interactions and poor tolerability may limit or prevent its use. Although data to support such intervention presently is limited, clinically challenging CM cases may benefit from combination therapy. 'Real world' studies are needed to evaluate such polytherapy, along with studies intended to assess the long-term safety of the individual therapies and their use during pregnancy and breast-feeding.

Onset, Maintenance, and Cessation of Effect of Galcanezumab for Prevention of Migraine: A Narrative Review of Three Randomized Placebo-Controlled Trials

Introduction

Galcanezumab, a humanized monoclonal antibody that binds to calcitonin gene-related peptide, is approved for the preventive treatment of migraine in adults. It is self-administered once monthly as a subcutaneous injection. This paper describes the time course of effect of galcanezumab in patients with episodic and chronic migraine.

Methods

Data were based on three double-blind, placebo-controlled, phase 3 studies. Patients (1773 episodic and 1113 chronic) were randomized (2:1:1) to monthly doses of placebo, galcanezumab 120 mg with a 240 mg loading dose, or galcanezumab 240 mg (January 2016–March 2017). Onset of effect was determined using a sequential analysis approach based on earliest time point at which galcanezumab achieved and subsequently maintained statistical superiority to placebo. Maintenance of effect was a comparison of the percentages of galcanezumab- and placebo-treated patients with maintenance of at least 50% response at the individual patient level. Cessation of effect was determined during a 4-month post-treatment period on the basis of change from baseline in monthly migraine headache days.

Results

Galcanezumab led to a lower percentage of patients who had a migraine headache on the first day after injection, provided maintenance of effect throughout the duration of the double-blind treatment period, and gradually lost effect without signs of rebound headache throughout the post-treatment period in most patients with episodic and chronic migraine.

Conclusion

Galcanezumab is a novel preventive therapeutic option for adult patients with migraine that has early onset of action, maintenance of effect, and gradual reduction of effect upon treatment cessation.

Trial Registration

ClinicalTrials.gov: NCT02614183 (EVOLVE-1); NCT02614196 (EVOLVE-2); NCT02614261 (REGAIN).

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01632-x.

Pharmacokinetics, Pharmacodynamics and Drug-Drug Interactions of New Anti-Migraine Drugs-Lasmiditan, Gepants, and Calcitonin-Gene-Related Peptide (CGRP) Receptor Monoclonal Antibodies

In the last few years, there have been significant advances in migraine management and prevention. Lasmiditan, ubrogepant, rimegepant and monoclonal antibodies (erenumab, fremanezumab, galcanezumab, and eptinezumab) are new drugs that were launched on the US pharmaceutical market; some of them also in Europe. This publication reviews the available worldwide references on the safety of these anti-migraine drugs with a focus on the possible drug–drug (DDI) or drug–food interactions. As is known, bioavailability of a drug and, hence, its pharmacological efficacy depend on its pharmacokinetics and pharmacodynamics, which may be altered by drug interactions. This paper discusses the interactions of gepants and lasmiditan with, i.a., serotonergic drugs, CYP3A4 inhibitors, and inducers or breast cancer resistant protein (BCRP) and P-glycoprotein (P-gp) inhibitors. In the case of monoclonal antibodies, the issue of pharmacodynamic interactions related to the modulation of the immune system functions was addressed. It also focuses on the effect of monoclonal antibodies on expression of class Fc gamma receptors (FcγR).

Migraine Headache Day Response Rates and the Implications to Patient Functioning: An Evaluation of 3 Randomized Phase 3 Clinical Trials of Galcanezumab in Patients With Migraine

OBJECTIVE

This post hoc study investigated the relationship between patient response in terms of migraine headache day reduction and patient-reported outcomes of health-related quality of life (HRQoL) and disability categories.

BACKGROUND

Migraine causes considerable disease-related disability and negatively impacts HRQoL of patients. Calcitonin gene-related peptide inhibitors improve these outcomes and may eliminate disability due to migraine in some patients.

METHODS

Analyses used data from 3 double-blind, placebo (PBO)-controlled, phase 3 studies in adults with episodic migraine (EM) (EVOLVE-1: N = 858 and EVOLVE-2: N = 915) or chronic migraine (CM) (REGAIN: N = 1113). Patients were randomized 2:1:1 to subcutaneous injection of PBO, galcanezumab (GMB) 120 mg, or GMB 240 mg once monthly for 6 months in EVOLVE-1 and -2 and for 3 months in REGAIN. Primary endpoint was overall mean change from baseline in monthly migraine headache days. Patients were divided into 4 response-level groups based on percent change from baseline (<30%, ≥30% to <50%, ≥50% to <75%, ≥75%). Patient-reported outcomes included the 14-item Migraine-Specific Quality of Life Questionnaire version 2.1 (MSQ) and Migraine Disability Assessment (MIDAS) questionnaire.

RESULTS

Among patients with migraine, mean improvements from baseline in MSQ domain scores increased with each successive level of migraine headache day response. On a 100-pt scale, increases in Role Function-Restrictive score in EM were 16.8 and 36.0 at the <30% and ≥75% response levels, respectively, and for CM were 10.7 and 46.5. Similar patterns in scores were observed for the Role Function-Preventive and Emotional Function domains. Examination of improvement in MSQ item score by treatment group showed that, in patients with EM, approximately 10 to 20% more GMB-treated patients (N = 796 for GMB 120 mg and GMB 240 mg) had improvements in all 14 MSQ items compared with PBO-treated patients (N = 773) (all P < .001). In patients with CM, 3 to 16% more GMB-treated patients (N = 507) had improvements in the 14 MSQ items compared with PBO (N = 494), though differences were statistically significant in only 19 of 28 comparisons. At baseline, mean MIDAS scores (EM, 33.1; CM, 67.2) indicated severe mean disability for patients with EM and very severe disability for patients with CM. Among patients with EM, 215 of 425 (50.6%) of those treated with GMB 120 mg and 212 of 413 (51.3%) treated with 240 mg had little/no disability due to migraine after 6 months (PBO: 277 of 832 (33.3%), P < .001 for both). Among patients with CM, 50 of 254 (19.7%) of those treated with GMB 120 mg and 54 of 258 (20.9%) treated with 240 mg reached the level of little/no disability after 3 months of treatment (PBO: 70 of 504 (13.9%), P = .045 for 120 mg, P = .017 for 240 mg).

CONCLUSIONS

Because migraine greatly impairs an individual's ability to participate in activities of daily living, measurements of HRQoL are essential in clinical research. This study showed that function in daily life, as measured by MSQ score, improved as migraine headache days were reduced and that GMB-treated patients were more likely to see improvement in MSQ item scores compared with PBO-treated patients. Elimination of migraine-related disability was also more frequent in GMB-treated patients compared with placebo-treated patients.

Characterization of the peripheral FAAH inhibitor, URB937, in animal models of acute and chronic migraine

Inhibiting the activity of fatty-acid amide hydrolase (FAAH), the enzyme that deactivates the endocannabinoid anandamide, enhances anandamide-mediated signaling and holds promise as a molecular target for the treatment of human pathologies such as anxiety and pain. We have previously shown that the peripherally restricted FAAH inhibitor, URB937, prevents nitroglycerin-induced hyperalgesia - an animal model of migraine - and attenuates the activation of brain areas that are relevant for migraine pain, e.g. trigeminal nucleus caudalis and locus coeruleus. The current study is aimed at profiling the behavioral and biochemical effects of URB937 in animal models of acute and chronic migraine. We evaluated the effects of URB937 in two rat models that capture aspects of acute and chronic migraine, and are based on single or repeated administration of the vasodilating drug, nitroglycerin (NTG). In addition to nocifensive behavior, in trigeminal ganglia and medulla, we measured mRNA levels of neuropeptides and pro-inflammatory cytokines along with tissue levels of anandamide and palmitoylethanolamide (PEA), an endogenous agonist of peroxisome proliferator-activated receptor type-a (PPAR-a), which is also a FAAH substrate. In the acute migraine model, we also investigated the effect of subtype-selective antagonist for cannabinoid receptors 1 and 2 (AM251 and AM630, respectively) on nocifensive behavior and on levels of neuropeptides and pro-inflammatory cytokines. In the acute migraine paradigm, URB937 significantly reduced hyperalgesia in the orofacial formalin test when administered either before or after NTG. This effect was accompanied by an increase in anandamide and PEA levels in target neural tissue, depended upon CB1 receptor activation, and was associated with a decrease in calcitonin gene-related peptide (CGRP), substance P and cytokines TNF-alpha and IL-6 mRNA. Similar effects were observed in the chronic migraine paradigm, where URB937 counteracted NTG-induced trigeminal hyperalgesia and prevented the increase in neuropeptide and cytokine transcription. The results show that peripheral FAAH inhibition by URB937 effectively reduces both acute and chronic NTG-induced trigeminal hyperalgesia, likely via augmented anandamide-mediated CB1 receptor activation. These effects are associated with inhibition of neuropeptidergic and inflammatory pathways.

The Role of the Kynurenine Signaling Pathway in Different Chronic Pain Conditions and Potential Use of Therapeutic Agents

Tryptophan (TRP) is an essential, aromatic amino acid catabolized by indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) enzymes into kynurenine. The IDO enzyme is expressed in peripheral tissues and the central nervous system. Another enzyme of interest in the kynurenine signaling pathway is kynurenine 3-monooxygenase (KMO). The purpose of this review is to discuss the role of TRP and the kynurenine signaling pathway in different chronic pain patients. The IDO-1, IDO-2, and KMO enzymes and the kynurenine metabolite have been shown to be involved in the pathogenesis of neuropathic pain and other painful conditions (migraine, cluster headache, etc.) as well as depressive behavior. We highlighted the analgesic potential of novel agents targeting the enzymes of the kynurenine signaling pathway to explore their efficacy in both future basic science and transitional studies. Upcoming studies conducted on animal models will need to take into consideration the differences in TRP metabolism between human and non-human species. Since chronic painful conditions and depression have common pathophysiological patterns, and the kynurenine signaling pathway is involved in both of them, future clinical studies should aim to have outcomes targeting not only pain, but also functionality, mood changes, and quality of life.

Real-world effectiveness and tolerability of erenumab: A retrospective cohort study

BACKGROUND

We aimed to systematically assess the effectiveness and tolerability of erenumab in a clinical setting, specifically a tertiary headache center.

METHODS

This was a retrospective cohort study at the John Graham Headache Center of Brigham and Women's Hospital. All patients who received erenumab from a headache specialist at the Center from 17 May 2018 to 31 January 2019 were included. Patients were contacted and underwent a structured clinical interview including information about erenumab use, perceived benefit, adverse events (AEs), and a global assessment of benefit versus drawbacks. Chart review was performed for patients who could not be contacted.

RESULTS

Four hundred and forty-four patients were initially identified and 418 were eligible. Two hundred and ninety-five participants completed the structured clinical interview portion of the study (response rate 70.6%). Seventy-four patient charts were additionally reviewed. Two hundred and forty-one participants had used erenumab. One hundred and sixty nine (70%) of participants experienced at least one adverse event, with constipation (43%), injection site reaction (24%), fatigue (15%), worsening headache (12%), and dizziness (11%) the five most commonly reported AEs. One hundred and sixty-eight participants (69.7%) felt that the benefits of erenumab outweighed any drawbacks. One hundred and fifty-one participants (62.7%) planned to continue using erenumab. Cost of treatment was cited by 12% of participants as a reason for either not starting or for stopping erenumab. Of patients who had an increase in dose due to lack of or partial efficacy, 46.5% felt that the dose increase was helpful. We identified one case of unintended pregnancy in our study population.

CONCLUSIONS

This large "real-world" study validates the findings of benefit of erenumab observed in clinical trials. Although adverse events were far more common in this population than in clinical trials, the planned continuation rate was relatively high. The substantial discrepancy between adverse events seen in clinical practice compared with clinical trials suggests systematic differences between clinical trial participants and patients who receive the treatment in clinical practice, or may indicate suboptimal ascertainment of adverse events in the trials. Clinicians should continue to be vigilant for adverse events in clinical practice.

Multidimensional assessment of the effects of erenumab in chronic migraine patients with previous unsuccessful preventive treatments: a comprehensive real-world experience

BACKGROUND

erenumab was safe and effective in clinical trials for the prevention of migraine. However, real-life data are still lacking. Here we report the clinical experience from an Italian real-world setting using erenumab in patients with chronic migraine experiencing previous unsuccessful preventive treatments.

METHODS

Seventy patients with chronic migraine and failure to ≥4 migraine preventive medication classes initially received monthly erenumab 70 mg s.c. Patients without a clinically meaningful improvement, considered as a > 30% reduction in headache days per month, after ≥3 months of therapy switched to monthly erenumab 140 mg. At the first administration and after 3 and 6 months, patients underwent extensive interviews to assess clinical parameters of disease severity and migraine-related disability and impact, and validated questionnaires to explore depression/anxiety, sleep, and quality of life (QoL). Finally, the Pain Catastrophizing Scale, Allodynia Symptom Checklist-12 and MIGraine attacks-Subjective COGnitive impairments scale (MIG-SCOG) were administered.

RESULTS

70% of patients were "responders" after the third administration of erenumab 70 mg, whereas 30% switched to erenumab 140 mg; 29% (6 pts) responded after the sixth administration. The headache-day frequency was reduced from 21.1 ± 0.7 to 11.4 ± 0.9 days after the third administration (p < 0.001) and to 8.9 ± 0.7 days after the sixth administration (p < 0.001). 53% and 70% of patients, respectively, showed a reduction of ≥50% of headache days/month after the third and the sixth administrations. Also improved were headache pain severity, migraine-related disability, and impact on daily living, QoL, pain catastrophizing and allodynia (all p < 0.001), quality of sleep, symptoms of depression or anxiety (p < 0.05) but not MIG-SCOG. There were no new adverse event signals.

CONCLUSION

These real-world data support monthly erenumab 70 or 140 mg s.c. as a safe and effective preventive treatment to reduce headache frequency and severity in chronic migraine patients experiencing previous unsuccessful preventive treatments.

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.

Neurotransmitter and tryptophan metabolite concentration changes in the complete Freund's adjuvant model of orofacial pain

BACKGROUND

The neurochemical background of the evolution of headache disorders, still remains partially undiscovered. Accordingly, our aim was to further explore the neurochemical profile of Complete Freund's adjuvant (CFA)-induced orofacial pain, involving finding the shift point regarding small molecule neurotransmitter concentrations changes vs. that of the previously characterized headache-related neuropeptides. The investigated neurotransmitters consisted of glutamate, γ-aminobutyric acid, noradrenalin and serotonin. Furthermore, in light of its influence on glutamatergic neurotransmission, we measured the level of kynurenic acid (KYNA) and its precursors in the kynurenine (KYN) pathway (KP) of tryptophan metabolism.

METHODS

The effect of CFA was evaluated in male Sprague Dawley rats. Animals were injected with CFA (1 mg/ml, 50 μl/animal) into the right whisker pad. We applied high-performance liquid chromatography to determine the concentrations of the above-mentioned compounds from the trigeminal nucleus caudalis (TNC) and somatosensory cortex (ssCX) of rats. Furthermore, we measured some of these metabolites from the cerebrospinal fluid and plasma as well. Afterwards, we carried out permutation t-tests as post hoc analysis for pairwise comparison.

RESULTS

Our results demonstrated that 24 h after CFA treatment, the level of glutamate, KYNA and that of its precursor, KYN was still elevated in the TNC, all diminishing by 48 h. In the ssCX, significant concentration increases of KYNA and serotonin were found.

CONCLUSION

This is the first study assessing neurotransmitter changes in the TNC and ssCX following CFA treatment, confirming the dominant role of glutamate in early pain processing and a compensatory elevation of KYNA with anti-glutamatergic properties. Furthermore, the current findings draw attention to the limited time interval where medications can target the glutamatergic pathways.

Immunogenicity Risk Assessment for an Engineered Human Cytokine Analogue Expressed in Different Cell Substrates

The purpose of this article is to illustrate how performance of an immunogenicity risk assessment at the earliest stage of product development can be instructive for critical early decision-making such as choice of host system for expression of a recombinant therapeutic protein and determining the extent of analytical characterization and control of heterogeneity in co- and post-translational modifications. Application of a risk-based approach for a hypothetical recombinant DNA analogue of a human endogenous cytokine with immunomodulatory functions is described. The manner in which both intrinsic and extrinsic factors could interact to influence the relative scale of risk associated with expression in alternative hosts, namely Chinese hamster ovary (CHO) cells, Pichia pastoris, Escherichia coli, or Nicotinia tabacum is considered in relation to the development of the investigational product to treat an autoimmune condition. The article discusses how particular product-related variants (primary amino acid sequence modifications and post-translational glycosylation or other modifications) and process-derived impurities (host cell proteins, endotoxins, beta-glucans) associated with the different expression systems might influence the impact of immunogenicity on overall clinical benefit versus risk for a therapeutic protein candidate that has intrinsic MHC Class II binding potential. The implications of the choice of expression system for relative risk are discussed in relation to specific actions for evaluation and measures for risk mitigation, including use of in silico and in vitro methods to understand intrinsic immunogenic potential relative to incremental risk associated with non-human glycan and protein impurities. Finally, practical guidance on presentation of this information in regulatory submissions to support clinical development is provided.

Population pharmacokinetic and exposure-response analysis of eptinezumab in the treatment of episodic and chronic migraine

Eptinezumab is a humanized mAb that targets calcitonin gene-related peptide and is under regulatory review for the prevention of episodic and chronic migraine (EM, CM). It is important to determine whether exposures achieved with intravenous (IV) administration of eptinezumab achieve desired pharmacologic effects. Population pharmacokinetics, including dose- and exposure-response analyses, were performed using patient-level data from the eptinezumab clinical trial program with IV doses ranging from 10 to 1000 mg in pharmacokinetic analyses or 10 to 300 mg in phase 2/3 clinical studies in patients with EM or CM. Exposure-response analysis explored the relationship between eptinezumab exposure metrics and efficacy parameters including monthly migraine days. The pharmacokinetic profile of eptinezumab was characterized by rapid attainment of maximum plasma concentration (ie, end of IV administration) and a terminal half-life of 27 days. Covariate analysis found that patient characteristics had no clinically significant effects on pharmacokinetic parameters and were insufficient to influence dosing. Dose- and exposure-response analyses found exposure with single doses ≥100 mg was associated with greater efficacy compared with doses ≤30 mg and a plateau of effect between 100 and 300 mg. A saturable inhibitory Emax model found the exposure over 12 weeks produced by single-dose eptinezumab 100 and 300 mg exceeded the exposure estimates required to achieve 90% of the maximal efficacy (EC90 ). This pharmacokinetic analysis of eptinezumab supports dosing every 12 weeks with no adjustment for patient characteristics, including exposures associated with 100- or 300-mg doses producing optimal efficacy effects. The similar efficacy profiles support 100 mg as the lowest effective dose of eptinezumab.

CGRP Inhibitors for Migraine

Migraine headaches remain a significant medical concern; lots of people are adversely affected. Many existing pharmacotherapies have disappointing results. The pathophysiology is related to calcitonin gene-related peptide (CGRP) pathways. There is hope for better efficacy from the now-available CGRP inhibitor drugs made available to patients suffering these cephalgias.

Eptinezumab in episodic migraine: A randomized, double-blind, placebo-controlled study (PROMISE-1)

OBJECTIVE

To evaluate the efficacy and safety of eptinezumab, a humanized anti-calcitonin gene-related peptide monoclonal antibody, in the preventive treatment of episodic migraine.

METHODS

The PRevention Of Migraine via Intravenous ALD403 Safety and Efficacy-1 (PROMISE-1) study was a phase 3, multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Adults with episodic migraine were randomized to eptinezumab 30 mg, 100 mg, 300 mg, or placebo for up to four intravenous (IV) doses administered every 12 weeks. The primary endpoint was change from baseline in monthly migraine days (MMDs) over weeks 1-12.

RESULTS

A total of 888 patients received treatment across 84 study sites. Mean MMDs at baseline was ∼8.6 across treatment groups. Eptinezumab 100 mg and 300 mg met the primary endpoint, significantly reducing MMDs across weeks 1-12 compared with placebo (30 mg, -4.0; 100 mg, -3.9, p = 0.0182; 300 mg, -4.3; placebo, -3.2, p = 0.0001). Treatment-emergent adverse events were reported by 58.4% (30 mg), 63.2% (100 mg), 57.6% (300 mg), and 59.5% (placebo) of patients. Treatment-emergent adverse events reported by ≥2% of eptinezumab-treated patients at an incidence greater than placebo included: upper respiratory tract infection (30 mg, 11.4%; 100 mg, 9.9%; 300 mg, 10.3%; placebo, 7.2%), and fatigue (30 mg, 2.3%; 100 mg, 3.6%; 300 mg, 3.6%; placebo, <1%).

CONCLUSION

Eptinezumab (100 mg or 300 mg) significantly reduced migraine frequency, was well tolerated, and had an acceptable safety profile when used for the preventive treatment of migraine in adults with episodic migraine. ClinicalTrials.gov identifier: NCT02559895.

Positive response to galcanezumab following treatment failure to onabotulinumtoxinA in patients with migraine: post hoc analyses of three randomized double-blind studies

Background and purpose

Humanized monoclonal antibody galcanezumab, which binds to calcitonin‐gene‐related peptide, has shown efficacy for episodic and chronic migraine prevention. These analyses evaluated galcanezumab response for migraine headache prevention in patients who previously failed onabotulinumtoxinA (‘nonresponse’ or ‘inadequate response’ or safety reasons).

Methods

Post hoc analyses included data from three double‐blind, placebo‐controlled, phase 3 episodic or chronic migraine studies; 2886 patients randomly received 120 or 240 mg galcanezumab or placebo. During double‐blind periods the study drug was administered subcutaneously once a month for 6 months in EVOLVE‐1 and ‐2 and for 3 months in REGAIN. The 120 mg groups received a 240 mg loading dose at month 1. Pooled analyses included 129 patients who failed onabotulinumtoxinA. Using mixed effect model repeat measurements, the least squares mean change from baseline in the number of migraine headache days (MHDs) was calculated for the first 3 months of treatment.

Results

For pooled analyses, significant decreases from baseline in the number of MHDs were observed for 120 mg (−3.91) and 240 mg (−5.27) galcanezumab overall versus placebo (−0.88) across 3‐month time points for patients who failed onabotulinumtoxinA. Corresponding data for patients with chronic migraine showed significant decreases: 120 mg (−3.18) and 240 mg (−4.26) galcanezumab versus placebo (0.16). Significant reductions in the number of MHDs per month with acute medication use included 120 mg galcanezumab (−4.35) and 240 mg galcanezumab (−4.55) versus placebo (−0.83). Estimates of ≥50% response during months 1–3 were 9.4% for placebo, 41.3% for 120 mg galcanezumab and 47.5% for 240 mg galcanezumab.

Conclusion

Galcanezumab is an option for prevention of migraine in patients who have previously failed onabotulinumtoxinA preventive therapy.

Rapid Onset of Effect of Galcanezumab for the Prevention of Episodic Migraine: Analysis of the EVOLVE Studies

Objective

To evaluate onset of effect of galcanezumab in patients with episodic migraine.

Background

Galcanezumab is a monoclonal antibody that binds to calcitonin gene‐related peptide and is indicated for preventive treatment of migraine.

Design/Methods

Data on the primary outcome measure were analyzed from 2 previously published double‐blind, Phase 3 studies (EVOLVE‐1 [N = 858] and EVOLVE‐2 [N = 915]) wherein adult patients with episodic migraine were randomized to receive monthly subcutaneous injections of galcanezumab 120 mg (with 240‐mg loading dose) or 240 mg or placebo for up to 6 months. Monthly onset of effect was defined as the earliest month at which galcanezumab achieved and subsequently maintained statistical superiority to placebo on the mean change from baseline in the number of monthly migraine headache days (MHDs). If onset occurred in Month 1, weekly onset was evaluated and defined as the earliest week at which galcanezumab statistically separated from placebo and maintained statistical separation for remaining weeks in that month. Day of onset of effect was also analyzed, as were monthly and weekly onset, for occurrence of ≥50% reduction from baseline in number of MHDs.

Results

For both studies, change from baseline in monthly MHDs showed a statistically significant separation of galcanezumab from placebo at Month 1 and each subsequent month (each P < .001). Analysis of the first month for both studies indicated onset of effect in the first week, with galcanezumab‐treated patients having significantly higher odds of having fewer MHDs in the first week (odds ratio [95% confidence interval] for EVOLVE‐1, 2.71 [2.00, 3.66], and for EVOLVE‐2, 2.88 [2.16, 3.86]; both P < .001) and each subsequent week compared with placebo‐treated patients (P ≤ .004). Daily analysis showed onset of effect at Day 1 (first day after injection day). Galcanezumab also demonstrated superiority to placebo on occurrence of ≥50% reduction in MHDs starting at Week 1 (percentage of patients with 50% response in galcanezumab group vs placebo group for EVOLVE‐1, 54.3% vs 32.4% [P < .001], and for EVOLVE‐2, 59.4% vs 38.0% [P < .001]).

Conclusion

Rapid onset of preventive effect on the first day after injection of galcanezumab was confirmed in both studies of episodic migraine.

Antibodies Targeting Chemokine Receptors CXCR4 and ACKR3

Dysregulation of the chemokine system is implicated in a number of autoimmune and inflammatory diseases, as well as cancer. Modulation of chemokine receptor function is a very promising approach for therapeutic intervention. Despite interest from academic groups and pharmaceutical companies, there are currently few approved medicines targeting chemokine receptors. Monoclonal antibodies (mAbs) and antibody-based molecules have been successfully applied in the clinical therapy of cancer and represent a potential new class of therapeutics targeting chemokine receptors belonging to the class of G protein-coupled receptors (GPCRs). Besides conventional mAbs, single-domain antibodies and antibody scaffolds are also gaining attention as promising therapeutics. In this review, we provide an extensive overview of mAbs, single-domain antibodies, and other antibody fragments targeting CXCR4 and ACKR3, formerly referred to as CXCR7. We discuss their unique properties and advantages over small-molecule compounds, and also refer to the molecules in preclinical and clinical development. We focus on single-domain antibodies and scaffolds and their utilization in GPCR research. Additionally, structural analysis of antibody binding to CXCR4 is discussed. SIGNIFICANCE STATEMENT: Modulating the function of GPCRs, and particularly chemokine receptors, draws high interest. A comprehensive review is provided for monoclonal antibodies, antibody fragments, and variants directed at CXCR4 and ACKR3. Their advantageous functional properties, versatile applications as research tools, and use in the clinic are discussed.

A new era for migraine: Pharmacokinetic and pharmacodynamic insights into monoclonal antibodies with a focus on galcanezumab, an anti-CGRP antibody

PURPOSE

To review pharmacokinetic and pharmacodynamic characteristics of antibodies that bind to soluble ligands within the framework of calcitonin gene-related peptide antibodies.

OVERVIEW

Calcitonin gene-related peptide has been implicated in the pathophysiology of migraine. Galcanezumab is an antibody that binds to the ligand calcitonin gene-related peptide. Other antibodies that target calcitonin gene-related peptide include eptinezumab and fremanezumab. To understand how antibodies can affect the extent and duration of free ligand concentrations, it is important to consider the dose and pharmacokinetics of an antibody, and the kinetics of the ligand and antibody-ligand complex. Insights regarding the pharmacokinetic/pharmacodynamic properties of galcanezumab as a probe antibody drug and calcitonin gene-related peptide as its binding ligand regarding its clinical outcomes are provided.

DISCUSSION

Antibodies are administered parenterally because oral absorption is limited by gastrointestinal degradation and inefficient diffusion through the epithelium. The systemic absorption of antibodies following intramuscular or subcutaneous administration most likely occurs via convective transport through lymphatic vessels into blood. The majority of antibody elimination occurs via intracellular catabolism into peptides and amino acids following endocytosis. Binding of ligand to an antibody reduces the free ligand that is available to interact with the receptor and efficacy is driven by the magnitude and duration of the reduction in free ligand concentration. A galcanezumab pharmacokinetic/pharmacodynamic model shows that galcanezumab decreases free calcitonin gene-related peptide concentrations in a dose- and time-dependent manner and continues to suppress free calcitonin gene-related peptide with repeated dosing. The model provides evidence for a mechanistic linkage to galcanezumab therapeutic effects for the preventive treatment of migraine.

Are antimigraine drugs that influence CGRP levels justified?

Migraine is one of the most common disorders found in everyday clinical practice. Although migraines are not directly life-threatening or permanently disabling, the severity of the pain and symptoms that characterize a migraine attack often prevent normal work and cause difficulties in everyday life. Migraines also affect the patient's family, who often experience stress and depression in response to the patient's condition. Available therapy, used in both acute and chronic treatments, might not provide sufficient improvement. Due to problems like therapy inefficacy, side effects, and intolerance, patients often stop treatments. Recent studies have indicated that drugs that act through calcitonin gene-related peptide (CGRP) can significantly improve migraine therapy. Here, we review results from currently available clinical trials on CGRP receptor antagonists and anti-CGRP monoclonal antibodies.

Calcitonin Gene-Related Peptide Modulators - The History and Renaissance of a New Migraine Drug Class

Several lines of evidence pointed to an important role for CGRP in migraine. These included the anatomic colocalization of CGRP and its receptor in sensory fibers innervating pain-producing meningeal blood vessels, its release by trigeminal stimulation, the observation of elevated CGRP in the cranial circulation during migraine with normalization concomitant with headache relief by sumatriptan, and translational studies with intravenous (IV) CGRP that evoked migraine only in migraineurs. The development of small molecule CGRP receptor antagonists (CGRP-RAs) that showed clinical antimigraine efficacy acutely and prophylactically in randomized placebo-controlled clinical trials subsequently gave definitive pharmacological proof of the importance of CGRP in migraine. More recently, CGRP target engagement imaging studies using a CGRP receptor PET ligand [¹¹ C]MK-4232 demonstrated that there was no brain CGRP receptor occupancy at clinically effective antimigraine doses of telcagepant, a prototypic CGRP-RA. Taken together, these data indicated that (1) the therapeutic site of action of the CGRP-RAs was peripheral not central; (2) that IV CGRP had most likely evoked migraine through an action at sites outside the blood-brain barrier; and (3) that migraine pain was therefore, at least in part, peripheral in origin. The evolution of CGRP migraine science gave impetus to the development of peripherally acting drugs that could modulate CGRP chronically to prevent frequent episodic and chronic migraine. Large molecule biologic antibody (mAb) approaches that are given subcutaneously to neutralize circulating CGRP peptide (fremanezumab, galcanezumab) or block CGRP receptors (erenumab) have shown consistent efficacy and tolerability in multicenter migraine prevention trials and are now approved for clinical use. Eptinezumab, a CGRP neutralizing antibody given IV, shows promise in late stage clinical development. Recently, orally administered next-generation small molecule CGRP-RAs have been shown to have safety and efficacy in acute treatment (ubrogepant and rimegepant) and prevention (atogepant) of migraine, giving additional CGRP-based therapeutic options for migraine patients.

CGRP Antagonists for the Treatment of Chronic Migraines: a Comprehensive Review

PURPOSE OF REVIEW

The purpose of the following review is to summarize the most recent understanding of migraine pathophysiology, as well as of basic and clinical science pharmacologic literature regarding the development of calcitonin gene receptor peptide (CGRP) antagonists as a novel therapeutic modality for the treatment of migraine headaches. A review is provided of erenumab, the first of its class FDA approved CGRP antagonist.

RECENT FINDINGS

Despite its high prevalence, the occurrence and treatment of migraine headaches is poorly understood. Erenumab and CGRP antagonists as a whole significantly reduce the average number of migraine days experienced in migraine sufferers. CGRP antagonists appear to significantly improve treatment outcomes in patients who suffer from episodic and chronic migraines. Erenumab is the first CGRP antagonist to be FDA approved for public use; however, further development of biologics in this class is underway.

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

Calcitonin gene-related peptide (CGRP) is a neuropeptide with a pivotal role in the pathophysiology of migraine. Blockade of CGRP is a new therapeutic target for patients with migraine. CGRP and its receptors are distributed not only in the central and peripheral nervous system but also in the cardiovascular system, both in blood vessels and in the heart. We reviewed the current evidence on the role of CGRP in the cardiovascular system in order to understand the possible short- and long-term effect of CGRP blockade with monoclonal antibodies in migraineurs.

In physiological conditions, CGRP has important vasodilating effects and is thought to protect organs from ischemia. Despite the aforementioned cardiovascular implication, preventive treatment with CGRP antibodies has shown no relevant cardiovascular side effects. Results from long-term trials and from real life are now needed.

The Role of Calcitonin Gene Related Peptide (CGRP) in Neurogenic Vasodilation and Its Cardioprotective Effects

Calcitonin gene-related peptide (CGRP) is a highly potent vasoactive peptide released from sensory nerves, which is now proposed to have protective effects in several cardiovascular diseases. The major α-form is produced from alternate splicing and processing of the calcitonin gene. The CGRP receptor is a complex composed of calcitonin like receptor (CLR) and a single transmembrane protein, RAMP1. CGRP is a potent vasodilator and proposed to have protective effects in several cardiovascular diseases. CGRP has a proven role in migraine and selective antagonists and antibodies are now reaching the clinic for treatment of migraine. These clinical trials with antagonists and antibodies indicate that CGRP does not play an obvious role in the physiological control of human blood pressure. This review discusses the vasodilator and hypotensive effects of CGRP and the role of CGRP in mediating cardioprotective effects in various cardiovascular models and disorders. In models of hypertension, CGRP protects against the onset and progression of hypertensive states by potentially counteracting against the pro-hypertensive systems such as the renin-angiotensin-aldosterone system (RAAS) and the sympathetic system. With regards to its cardioprotective effects in conditions such as heart failure and ischaemia, CGRP-containing nerves innervate throughout cardiac tissue and the vasculature, where evidence shows this peptide alleviates various aspects of their pathophysiology, including cardiac hypertrophy, reperfusion injury, cardiac inflammation, and apoptosis. Hence, CGRP has been suggested as a cardioprotective, endogenous mediator released under stress to help preserve cardiovascular function. With the recent developments of various CGRP-targeted pharmacotherapies, in the form of CGRP antibodies/antagonists as well as a CGRP analog, this review provides a summary and a discussion of the most recent basic science and clinical findings, initiating a discussion on the future of CGRP as a novel target in various cardiovascular diseases.