Treatment of resistant chronic migraine with anti-CGRP monoclonal antibodies: a systematic review

Switching CGRP(r) MoAbs in migraine: what evidence?

INTRODUCTION

Approximately 50% of patients that receive a CGRP(r) MoAb for the preventative treatment of migraine are expected to discontinue therapy. For patients that discontinue CGRP(r) MoAb therapy, few clinical options are available. One potential option is to switch CGRP(r) MoAbs, however, data concerning the efficacy of this intervention is scarce.

AREAS COVERED

This manuscript aims to summarize all available data concerning the potential efficacy of switching CGRP(r) MoAbs following previous medication discontinuation. Data was sourced by completing a database search for the terms: 'CGRP monoclonal antibody switch OR CGRP monoclonal antibody switching.'

EXPERT OPINION

While data considering the potential efficacy of CGRP(r) switching continues to grow, our expert opinion supports the most recent European Headache Federation statement regarding CGRP(r) MoAb prescribing practices, concluding that there remains insufficient data to determine the efficacy of this intervention. As this topic is of significant clinical importance, we recommend a call-to-action to expand on current data considering the therapeutic options for patients that discontinue CGRP(r) MoAb therapy.

Migraine and Its Treatment from the Medicinal Chemistry Perspective

Migraine is a disease of neurovascular origin that affects the quality of life of more than one billion people and ranks sixth among the most common diseases in the world. Migraine is characterized by a moderate or severe recurrent and throbbing headache, accompanied by nausea, vomiting, and photo-phonophobia. It usually starts in adolescence and is twice as common in women as in men. It is classified as with or without aura and has chronic or acute treatment types according to the frequency of occurrence. In acute treatment, analgesics that relieve pain in the fastest way are preferred, while there are different options in chronic treatment. While non-specific methods were used in the treatment of migraine until the 1950s, triptans, ditans, and CGRP-receptor-dependent therapies (monoclonal antibodies and gepants) started to be used in the clinic more recently. In this Review, we focus on the synthesis, side effects, and pharmacological and pharmacokinetic properties of FDA-approved drugs used in acute and preventive-specific treatment of migraine.

Migraine Comorbidities

Novel knowledge about the interrelationships and reciprocal effects of migraine and epilepsy, migraine and mood disorders, or migraine and irritable bowel syndrome has emerged in recent decades. Over time, comorbid pathologies associated with migraine that share common physiopathological mechanisms were studied. Among these studied pathologies is epilepsy, a disorder with common ion channel dysfunctions as well as dysfunctions in glutamatergic transmission. A high degree of neuronal excitement and ion channel abnormalities are associated with epilepsy and migraine and antiepileptic drugs are useful in treating both disorders. The coexistence of epilepsy and migraine may occur independently in the same individual or the two may be causally connected. The relationship between cortical spreading depression (CSD) and epileptic foci has been suggested by basic and clinical neuroscience research. The most relevant psychiatric comorbidities associated with migraine are anxiety and mood disorders, which influence its clinical course, treatment response, and clinical outcome. The association between migraine and major depressive disorder can be explained by a robust molecular genetic background. In addition to its role as a potent vasodilator, CGRP is also involved in the transmission of nociception, a phenomenon inevitably linked with the stress and anxiety caused by frequent migraine attacks. Another aspect is the role of gut microbiome in migraine's pathology and the gut-brain axis involvement. Irritable bowel syndrome patients are more likely to suffer migraines, according to other studies. There is no precise explanation for how the gut microbiota contributes to neurological disorders in general and migraines in particular. This study aims to show that migraines and comorbid conditions, such as epilepsy, microbiota, or mood disorders, can be connected from the bench to the bedside. It is likely that these comorbid migraine conditions with common pathophysiological mechanisms will have a significant impact on best treatment choices and may provide clues for future treatment options.

Unmet Needs in the Acute Treatment of Migraine

Migraine represents the most common neurologic disorder, ranking second among the world's causes of disability [expressed as years lived with disability (YLDs)]. Patients often do not receive the best therapy because of safety issues, tolerance, and prescription accessibility. General practitioners are not always educated about the disease, and specialists are few and often difficult to reach. Therapies are limited and have many side effects that can impede the prescription. Prophylactic therapy is recommended in case of four or more headaches a month, eight or more headache days a month, debilitating headaches, and medication-overuse headaches. The available therapeutic options are in constant development. The classic one consists of non-specific drugs: β-blockers, tricyclics, antiepileptics, and botulinum toxin. Monoclonal antibodies targeting the calcitonin gene receptor (CGRP) peptide or its receptor are the only ones specifically designed to treat migraine. Their efficiency and convenient safety profile have been demonstrated in a number of trials versus both placebo and classic therapies. The treatment of acute migraine attack consists of medications designed to affect the painful symptoms. For over 30 years, the cornerstones of treatment in clinical practice have continued to be represented by triptans and non-steroidal anti-inflammatory drugs (NSAIDs), with the well-know related adverse effects. Opioids are used inappropriately and overprescribed. Polytherapy is strongly not recommended but is still a common practice because treatment is not optimized and thus not efficient. Great promise comes from gepants, also targeting CGRP, and ditans, 5-HT1F receptor agonists. They seem to outweigh the risk of medication overuse headache because of their efficacy and rapid onset and have no cardiovascular contraindications. Nonetheless, these points remain to be confirmed. Although therapies have been implemented in the last years, significant unmet treatment needs remain a reality in patients' lives. This commentary aims to identify the most important unmet needs in the acute treatment of migraine, analyzing the current status of available therapies and their limits. We also analyzed some of the prophylactic therapies available, especially focusing on anti-CGRP monoclonal antibodies, to better understand the importance of setting a therapeutic strategy that includes the two modes, both acute and prophylactic, to reach the best result. We hope that having an overview of the shortcomings will help to provide constructive ideas for improvement.

Recent advances in structural mass spectrometry methods in the context of biosimilarity assessment: from sequence heterogeneities to higher order structures

Biotherapeutics and their biosimilar versions have been flourishing in the biopharmaceutical market for several years. Structural and functional characterization is needed to achieve analytical biosimilarity through the assessment of critical quality attributes as required by regulatory authorities. The role of analytical strategies, particularly mass spectrometry-based methods, is pivotal to gathering valuable information for the in-depth characterization of biotherapeutics and biosimilarity assessment. Structural mass spectrometry methods (native MS, HDX-MS, top-down MS, etc.) provide information ranging from primary sequence assessment to higher order structure evaluation. This review focuses on recent developments and applications in structural mass spectrometry for biotherapeutic and biosimilar characterization.

Peripherally acting anti-CGRP monoclonal antibodies alter cortical gray matter thickness in migraine patients: A prospective cohort study

Migraine is underpinned by central nervous system neuroplastic alterations thought to be caused by the repetitive peripheral afferent barrage the brain receives during the headache phase (cortical hyperexcitability). Calcitonin gene-related peptide monoclonal antibodies (anti-CGRP-mAbs) are highly effective migraine preventative treatments. Their ability to alter brain morphometry in treatment-responders vs. non-responders is not well understood. Our aim was to determine the effects of the anti-CGRP-mAb galcanezumab on cortical thickness after 3-month treatment of patients with high-frequency episodic or chronic migraine. High-resolution magnetic resonance imaging was performed pre- and post-treatment in 36 migraine patients. In this group, 19 patients were classified responders (≥50 % reduction in monthly migraine days) and 17 were considered non-responders (<50 % reduction in monthly migraine days). Following cross-sectional processing to analyze the baseline differences in cortical thickness, two-stage longitudinal processing and symmetrized percent change were conducted to investigate treatment-related brain changes. At baseline, no significant differences were found between the responders and non-responders. After 3-month treatment, decreased cortical thickness (compared to baseline) was observed in the responders in regions of the somatosensory cortex, anterior cingulate cortex, medial frontal cortex, superior frontal gyrus, and supramarginal gyrus. Non-responders demonstrated decreased cortical thickness in the left dorsomedial cortex and superior frontal gyrus. We interpret the cortical thinning seen in the responder group as suggesting that reduction in head pain could lead to changes in neural swelling and dendritic complexity and that such changes reflect the recovery process from maladaptive neural activity. This conclusion is further supported by our recent study showing that 3 months after treatment initiation, the incidence of premonitory symptoms and prodromes that are followed by headache decreases but not the incidence of the premonitory symptoms or prodromes themselves (that is, cortical thinning relates to reductions in the nociceptive signals in the responders). We speculate that a much longer recovery period is required to allow the brain to return to a more 'normal' functioning state whereby prodromes and premonitory symptoms no longer occur.

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.

Effectiveness and Safety of Eptinezumab in Episodic and Chronic Migraine Headache in the UAE: A Retrospective Study

INTRODUCTION

Eptinezumab is a humanized IgG1 immunoglobulin monoclonal antibody administered intravenously as a preventative migraine treatment. Previously conducted randomized, double-blind, placebo-controlled trials exhibited significant reductions in monthly migraine frequency among adults experiencing episodic and chronic migraine. The present study seeks to expand upon the current findings and to evaluate eptinezumab's efficacy as a preventative treatment for chronic and episodic migraine patients in the United Arab Emirates. This study is intended to represent the first real-world evidence and will hopefully serve as a valuable complement to the existing literature on the subject.

METHODS

This was a retrospective exploratory study. The participants included within the study were adult (≥ 18 years) patients diagnosed with either episodic or chronic migraine. Patients were categorized according to their history of previous preventative treatment failure. For the final assessment of treatment efficacy, we included only patients with a minimum of 6 months of clinical follow-up data. Patients were assessed at baseline for their monthly migraine frequency and assessed again at months 3 and 6. The primary objective was to evaluate the efficacy of eptinezumab in reducing migraine frequency among chronic and episodic migraine patients.

RESULTS

A total of 100 participants were identified, of whom 53 completed the study protocol at month 6. Of the total, 40 (75.47%) were female, 46 (86.79%) were Emirati locals, and 16 (30.19%) were pharmaceutically naïve, having never tried any prior preventative therapy. Additionally, 25 (47.17%) patients met the criteria for chronic migraine (CM), whereas the remaining 28 (52.83%) were diagnosed with episodic migraine (EM). The baseline monthly migraine frequency (MMD) was 12.23 (4.97) days across all participants, 15.56 (3.97) for CM patients, and 9.25 (3.76) for EM patients; by month 6, these frequencies reduced to 3.66 (4.21), 4.76 (5.32), and 2.68 (2.61), respectively. Overall, 58.49% of those enrolled experienced > 75% reduction in MMD frequency by month 6.

CONCLUSION

Patients enrolled in this trial experienced clinically significant reductions in MMD by month 6. Eptinezumab was well tolerated and with one AE of significance that led to discontinuation from the study.

Ten open questions in migraine prophylaxis with monoclonal antibodies blocking the calcitonin-gene related peptide pathway: a narrative review

The monoclonal antibodies (mAbs) blocking the calcitonin-gene related peptide (CGRP) pathway, collectively called here "anti-CGRP/rec mAbs", have dramatically improved preventive migraine treatment. Although their efficacy and tolerability were proven in a number of randomized controlled trials (RCTs) and, maybe even more convincingly, in real world settings, a number of open questions remain. In this narrative review, we will analyze published data allowing insight in some of the uncertainties related to the use of anti-CGRP/rec mAbs in clinical practice: their differential efficacy in migraine subtypes, outcome predictors, switching between molecules, use in children and adolescents, long-term treatment adherence and persistence, effect persistence after discontinuation, combined treatment with botulinum toxin or gepants, added-value and cost effectiveness, effectiveness in other headache types, and potential contraindications based on known physiological effects of CGRP. While recent studies have already provided hints for some of these questions, many of them will not find reliable and definitive answers before larger studies, registries or dedicated RCTs are available.

Clinical efficacy and safety of rimegepant in the treatment of migraine: a meta-analysis of randomized controlled trials

Background

This study aims to evaluate the clinical efficacy and safety of rimegepant for the treatment of migraine in adult patients using a meta-analysis.

Methods

The PubMed, EMBASE, and Cochrane Library were searched up to March 2022. Only randomized controlled trials (RCTs) that evaluated migraine and other comparator treatments in adult patients were included. The clinical response at the post-treatment evaluation, including acute pain free and relief effect, whereas the secondary outcomes were the risk of adverse events (AEs).

Results

A total of 4 RCTs involving 4,230 patients with episodic migraine were included. Outcome indicators for the number of pain free and relief patients at 2 h, 2-24 h, 2-48 h post-dose showed that rimegepant had better effects relative to the placebo [free at 2 h: OR = 1.84, 95% CI (1.55, 2.18), P < 0.00001; relief at 2 h: OR = 1.80, 95% CI (1.59, 2.04), P < 0.00001]. And there was no significant difference between the occurrence of adverse events in the experimental and control groups [OR = 1.29, 95% CI (0.99, 1.67), P = 0.06].

Conclusion

Rimegepant has better therapeutic effects compared to placebo and no significant difference in adverse events.

Biomarkers of Migraine: An Integrated Evaluation of Preclinical and Clinical Findings

In recent years, numerous efforts have been made to identify reliable biomarkers useful in migraine diagnosis and progression or associated with the response to a specific treatment. The purpose of this review is to summarize the alleged diagnostic and therapeutic migraine biomarkers found in biofluids and to discuss their role in the pathogenesis of the disease. We included the most informative data from clinical or preclinical studies, with a particular emphasis on calcitonin gene-related peptide (CGRP), cytokines, endocannabinoids, and other biomolecules, the majority of which are related to the inflammatory aspects and mechanisms of migraine, as well as other actors that play a role in the disease. The potential issues affecting biomarker analysis are also discussed, such as how to deal with bias and confounding data. CGRP and other biological factors associated with the trigeminovascular system may offer intriguing and novel precision medicine opportunities, although the biological stability of the samples used, as well as the effects of the confounding role of age, gender, diet, and metabolic factors should be considered.

Migraine headache pathophysiology

In both episodic and chronic migraine, headache is the most disabling symptom that requires medical care. The migraine headache is the most well-studied symptom of migraine pathophysiology. The trigeminal system and the central processing of sensory information transmitted by the trigeminal system are of considerable importance in the pathophysiology of migraine headache. Glutamate is the main neurotransmitter that drives activation of the ascending trigeminal and trigeminothalamic pathways. The neuropeptide, calcitonin gene-related peptide (CGRP) that is released by the trigeminal system, plays a crucial role in the neurobiology of headache. Peripheral and central sensitizations associated with trigeminal sensory processing are neurobiologic states that contribute to both the development of headache during a migraine attack and the maintenance of chronic migraine.

Migraine in physicians and final year medical students: A cross-sectional insight into prevalence, self-awareness, and knowledge from Pakistan

BACKGROUND

Despite its high prevalence, migraine remains underdiagnosed worldwide. A significant reason is the knowledge gap in physicians regarding diagnostic criteria, clinical features, and other clinical aspects of migraine.

AIM

To measure the knowledge deficit in physicians and medical students and to assess the prevalence of migraine in the same population.

METHODS

An online questionnaire was developed and distributed among physicians and final year medical students on duty in various medical and surgical specialties of Allied and DHQ Hospitals, Faisalabad, between October 2018 and October 2019. Inclusion criteria were public practicing physicians who experience headaches, while those who never experienced headaches were excluded. Different questions assessed respondents on their knowledge of triggers, diagnosis, management, and prophylaxis of the migraine headache. They were asked to diagnose themselves using embedded ICHD-3 diagnostic criteria for different types of migraine. Graphs, tables, and figures were made using Microsoft Office 2016 and Microsoft Visio, and data analysis was done in R Studio 1.4.

RESULTS

We had 213 respondents and 175 fulfilled inclusion criteria, with 99 (52%), 58 (30%) and 12 (6.3%) belonging to specialties of medicine, surgery, and others, respectively. Both genders were symmetrically represented (88 male and 87 female). Fifty-two (24.4%) of our 213 respondents were diagnosed with migraine, with 26 (50%) being aware of it. Females had higher prevalence among study participants (n = 28, 32.2%) compared to males (n = 20, 22.7%, P = 0.19). A majority (62%) of subjects never consulted any doctor for their headache. Similarly, a majority (62%) either never heard or did not remember the diagnostic criteria of migraine. Around 38% falsely believed that having any type of aura is essential for diagnosing migraine. The consultation rate was 37% (n = 65), and migraineurs were significantly more likely to have consulted a doctor, and a neurologist in particular (P < 0.001). Consulters and migraineurs fared better in the knowledge of diagnostic aspects of the disease than their counterparts. There was no significant difference in other knowledge aspects between consulters versus non-consulters and migraineurs versus non-migraineurs.

CONCLUSION

Critical knowledge gaps exist between physicians and medical students, potentially contributing to misdiagnosis and mismanagement of migraine.