Calcitonin Gene-Related Peptide (CGRP)-Targeted Monoclonal Antibodies and Antagonists in Migraine: Current Evidence and Rationale

Prevalence and burden of migraine in the United States: A systematic review

BACKGROUND

This study reviewed migraine prevalence and disability gathered through epidemiologic survey studies in the United States conducted over the past three decades. We summarized these studies and evaluated changing patterns of disease prevalence and disability.

METHODS

We conducted a systematic review of US studies addressing the prevalence, disability, and/or burden of migraine, including both episodic migraine (EM) and chronic migraine (CM). A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol was used in conjunction with the PubMed search engine. Eligible studies were published before February 2022, were conducted in the United States, included representative samples, and used a case definition of migraine based on the International Classification of Headache Disorders (ICHD). The primary measure of disease burden was the Migraine Disability Assessment Scale (MIDAS). The MIDAS measures days lost due to migraine over 3 months in three domains and defines groups with moderate (Grade III) or severe disability (Grade IV) using cut-scores.

RESULTS

Of the 1609 identified records, 26 publications from 11 US population-based studies met eligibility criteria. The prevalence of migraine in the population has remained relatively consistent for the past 30 years: ranging from 11.7% to 14.7% overall, 17.1% to 19.2% in women, and 5.6% to 7.2% in men in the studies reviewed. CM prevalence is 0.91% (1.3% among women and 0.5% of men) in adults and 0.8% in adolescents. The proportion of people with migraine and moderate-to-severe MIDAS disability (Grades III-IV), has trended upward across studies from 22.0% in 2005 to 39.0% in 2012, to 43.2% in 2016, and 42.4% in 2018. A consistently higher proportion of women were assigned MIDAS Grades III/IV relative to men.

CONCLUSION

The prevalence of migraine in the United States has remained stable over the past three decades while migraine-related disability has increased. The disability trend could reflect changes in reporting, study methodology, social and societal changes, or changes in exacerbating or remediating factors that make migraine more disabling, among other hypotheses. These issues merit further investigation.

Benefit of Dietary Supplementation of Nutraceuticals as an Integrative Approach for Management of Migraine: Evidence From Preclinical and Clinical Studies

PURPOSE OF REVIEW

To provide information from preclinical and clinical studies on the biological activity and health benefits of dietary inclusion of nutraceuticals as a safe, effective, non-pharmacological approach for the treatment of migraine.

RECENT FINDINGS

There is emerging evidence of the therapeutic benefit of nutraceuticals to inhibit oxidative stress, suppress inflammation, and prevent changes in the normal gut microbiome, which are implicated in migraine pathology. Nutraceuticals can be enriched in polyphenols, which act as molecular scavengers to reduce the harmful effects of reactive oxygen species and phytosterols that suppress inflammation. Nutraceuticals also function to inhibit dysbiosis and to maintain the commensal intestinal bacteria that produce anti-inflammatory molecules including short-chain fatty acids that can act systemically to maintain a healthy nervous system. Dietary inclusion of nutraceuticals that exhibit antioxidant, anti-inflammatory, and anti-nociceptive properties and maintain the gut microbiota provides a complementary and integrative therapeutic strategy for migraine.

Improvement of comorbid anxiety and depression in patients with migraine treated with injectable preventive calcitonin gene-related peptide antagonists: Review of clinical evidence

Background

Migraine is often associated with depression and anxiety, leading to a diminished quality of life. Calcitonin gene-related peptide (CGRP) antagonists have shown promise in treating migraines, but their effects on concurrent depression and anxiety have not been clarified.

Methods

A literature review was conducted on ClinicalTrials.gov, PubMed, Ovid Medline, and EMBASE focusing on phase 3 clinical trials, post-hoc analysis studies, and real-world evidence (RWE) published in the past 5 years. The review primarily utilized patient-reported outcome tools, such as the Patient Health Questionnaire-9, Hamilton Depression Rating Scale, Beck Depression Inventory-II, generalized anxiety disorder (GAD)-7, and Hamilton Anxiety Rating Scale (HARS), to assess anxiety and depression in relation to CGRP-targeted monoclonal antibodies.

Results

Out of 260 studies, 17 met the inclusion criteria. Eptinezumab lacked sufficient evidence regarding its impact on depression and anxiety. While sufficient evidence on its effect on comorbid anxiety was not available, fremanezumab was shown to significantly improve comorbid depression in one study while not achieving statistical significance in another. Erenumab and galcanezumab showed significant improvement in comorbid depression, implying possible benefits in patients with migraine. Galcanezumab showed faster relief from depressive symptoms than other injectable CGRP antagonists. Galcanezumab also exhibited improvements in GAD-7 scores for anxiety, although not statistically significant, whereas RWE showed promising HARS scores for both galcanezumab and erenumab.

Conclusions

Galcanezumab and erenumab appear to be more effective in improving concurrent depressive and anxiety symptoms in migraine patients than fremanezumab. Notably, these psychometric questionnaires were not the primary outcome measures of the trials and were not specifically designed to investigate the effects of these medications on depression or anxiety. Further research is needed to fully understand the impact of CGRP antagonists on mental health disorders associated with migraines. These findings have implications for enhancing the overall well-being and quality of life in individuals with migraines and comorbid psychiatric conditions.

Real-world effectiveness of erenumab in Japanese patients with migraine

Background

Real-world evidence of erenumab effectiveness in migraine patients in Asia with various comorbidities and multiple previous medication failures is still limited.

Methods

A 6-month single-center cohort study of 45 patients with episodic or chronic migraine (CM) treated with erenumab was conducted. In the cohort, 60.0% were switching from other calcitonin gene-related peptide monoclonal antibodies (CGRP mAbs), and 66.7% had ≥4 prophylaxis failures. The change in monthly migraine days (MMDs) from baseline and percentages of responders after treatment were calculated. Weekly migraine days (WMDs) were obtained at baseline and at months 1, 2 and 3 and were compared between weeks 2 and 4.

Results

In total, 36%, 47%, and 63% of patients had a ≥30% response at 1, 3, and 6 months, respectively. The cumulative percentage of patients achieving a ≥30% response over 6 months was 85%. Early responders (average ≥ 30% response at 1-3 months) accounted for 37.8%, 55.6%, and 25.9% of the total, CGRP mAb-naïve, and CGRP mAb-switching groups, respectively. Late responders (average < 30% response at 1-3 months and average ≥ 30% response at 4-6 months) accounted for 46.4%, 37.5%, and 58.8% of nonearly responders in the total, CGRP mAb-naïve, and CGRP mAb-switching groups, respectively. Mild adverse reactions were observed in 5 patients (11.1%). Wearing-off, defined as an increase in the number of WMDs ≥2 between week 2 and week 4, was observed in 2.4-12.5% at months 1-3.

Conclusion

Erenumab was effective in migraine patients. At least 4-6 months may be preferable for efficacy evaluation in patients switching to erenumab from other CGRP mAbs.

Calcitonin gene-related peptide antagonists in pregnancy: a disproportionality analysis in VigiBase®

BACKGROUND

Current evidence on the safety of calcitonin gene-related peptide antagonists (CGRP-A) in pregnancy for the treatment of both episodic and chronic migraine is scarce and does not yet provide definitive information. By querying VigiBase®, the World Health Organization global pharmacovigilance database, this study aimed to detect differences in the reporting frequency between CGRP-A and triptans in relation to pregnancy.

METHODS

Disproportionality analyses on de-duplicated safety reports collected in VigiBase® as of 31.05.2023 reporting exposure to CGRP-A in pregnancy with or without pregnancy outcomes. A Reporting Odds Ratio (ROR) with a 95% confidence interval (CI) was used as a measure of disproportionality and the threshold for the detection of a signal of disproportionate reporting was set with a 95% CI lower limit > 1.

FINDINGS

Four hundred sixty-seven safety reports reported exposure to CGRP-A in pregnancy, mostly originating from the United States of America (360/467, 77%), more frequently reported by patients (225/467, 48%), who were mainly females (431/467, 92%), and more frequently reported exposure to CGRP-A during pregnancy (400/467, 86%). Compared to triptans, no signals of disproportionate reporting were detected with CGRP-A either for the overall reporting of pregnancy-related safety reports (ROR 0.91, 95% CI 0.78-1.06), for the reporting of pregnancy outcomes (maternal and/or foetal/neonatal, ROR 0.54, 95% CI 0.45-0.66), or for the reporting of foetal/neonatal outcomes (ROR 0.53, 95% CI 0.41-0.68).

CONCLUSIONS

This study showed that, to date, there are no signals of increased reporting with CGRP-A compared to triptans in relation to pregnancy in VigiBase®. Future pharmacovigilance studies are needed to confirm these findings.

Metabolic and toxicological considerations regarding CGRP mAbs and CGRP antagonists to treat migraine in COVID-19 patients: a narrative review

INTRODUCTION

Migraine pharmacological therapies targeting calcitonin gene-related peptide (CGRP), including monoclonal antibodies and gepants, have shown clinical effect and optimal tolerability. Interactions between treatments of COVID-19 and CGRP-related drugs have not been reviewed.

AREAS COVERED

An overview of CGRP, a description of the characteristics of each CGRP-related drug and its response predictors, COVID-19 and its treatment, the interactions between CGRP-related drugs and COVID-19 treatment, COVID-19 and vaccination-induced headache, and the neurological consequences of Covid-19.

EXPERT OPINION

Clinicians should be careful about using gepants for COVID-19 patients, due to the potential drug interactions with drugs metabolized via CYP3A4 cytochrome. In particular, COVID-19 treatment (especially nirmatrelvir packaged with ritonavir, as Paxlovid) should be considered cautiously. It is advisable to stop or adjust the dose (10 mg atogepant when used for episodic migraine) of gepants when using Paxlovid (except for zavegepant). CGRP moncolconal antibodies (CGRP-mAbs) do not have drug - drug interactions, but a few days' interval between a COVID-19 vaccination and the use of CGRP mAbs is recommended to allow the accurate identification of the possible adverse effects, such as injection site reaction. Covid-19- and vaccination-related headache are known to occur. Whether CGRP-related drugs would be of benefit in these circumstances is not yet known.

Debunking myths in headache diagnosis for the pain practitioner

With headache being one of the most common chief complaints, it is essential for pain practitioners to interpret and differentiate a variety of headache characteristics to accurately diagnose and treat specific headache disorders. Certain misconceptions often lead to misdiagnosis. This article presents and discusses six myths about several common headache disorders (migraine, tension-type headache, cluster headache, cervicogenic headache, sinus headache, and occipital neuralgia) often encountered in clinical practice. The discussion is based primarily on the International Classification of Headache Disorders, 3rd edition and the latest studies. Recognizing and understanding the intricacies behind key headache diagnoses will help providers devise appropriate plans to better care for their patients.

Effects of CYP3A4 inhibition/induction and OATP inhibition on the pharmacokinetics of atogepant in healthy adults

Aim: Atogepant, a calcitonin gene-related peptide (CGRP) receptor antagonist, is a substrate of OATP and metabolized by CYP3A4. Effect of multiple-dose itraconazole (strong CYP3A4 inhibitor), single-dose rifampin (strong OATP inhibitor) and multiple-dose rifampin (strong CYP3A4 inducer) on single-dose pharmacokinetics (PK) and safety of atogepant were assessed. Methods: Two phase I, open-label, single-center, crossover trials enrolled healthy adults. Results: Cmax and AUC of atogepant increased when co-administered with itraconazole. Atogepant systemic exposure increased following co-administration with single-dose rifampin. Atogepant systemic exposure decreased with co-administration of multiple-dose rifampin. Treatment emergent adverse events (TEAEs) were predominantly mild or moderate, and included constipation, dizziness, headache and nauseas. Conclusion: Systemic exposure of atogepant increased significantly when co-administered with a strong CYP3A4 or OATP inhibitor and decreased significantly when co-administered with a strong CYP3A4 inducer.

Real-world evidence on the economic implications of CGRP-mAbs as preventive treatment of migraine

BACKGROUND

Calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) are approved in Europe as preventive treatment of migraine in patients with at least four monthly migraine days. Migraine gives rise to direct healthcare expenditures, but most of the economic burden of migraine is socioeconomic. Evidence on the socioeconomic implications of CGRP-mAbs is, however, limited. There is an increasing interest in supplementing evidence from randomised controlled trials (RCTs) with real-world evidence (RWE) to aid clinical decision making and inform decision making for migraine management. The objective of this study was to generate RWE on the health economic and socioeconomic implications of administering CGRP-mAbs to patients with chronic migraine (CM) and episodic migraine (high-frequency episodic migraine (HFEM), and low-frequency episodic migraine (LFEM)).

METHODS

Real-world data (RWD) on Danish patients with CM, HFEM, and LFEM were collected via two Danish patient organisations and two informal patient networks and used in a tailored economic model. Treatment effects of CGRP-mAbs on health economic and socioeconomic outcomes were estimated using a sub-sample of patients with CM who receive CGRP-mAb treatment.

RESULTS

A total of 362 patients (CM: 199 [55.0%], HFEM: 80 [22.1%], LFEM: 83 [22.9%]) were included in the health economic model (mean age 44.1 ± 11.5, 97.5% female, 16.3% received treatment with CGRP-mAbs), and 303 patients were included in the socioeconomic model (15.2% received treatment with CGRP-mAbs). Health economic savings from initiating CGRP-mAb treatment totalled €1,179 per patient with CM per year on average (HFEM: €264, LFEM: €175). Socioeconomic gains from initiating CGRP-mAb treatment totalled an average gross domestic product (GDP) gain of €13,329 per patient with CM per year (HFEM: €10,449, LFEM: €9,947).

CONCLUSION

Our results indicate that CGRP-mAbs have the potential to reduce both health economic expenditures and the socioeconomic burden of migraine. Health economic savings are used as a basis for health technology assessments (HTAs) of the cost-effectiveness of new treatments, which implies that important socioeconomic gains may not be given enough importance in decision making for migraine management.

Zavegepant: First Approval

Zavegepant is a third generation, small-molecule, calcitonin gene-related peptide (CGRP) receptor antagonist being developed by Pfizer, under a license from Bristol-Myers Squibb, for the prevention and treatment of chronic and episodic migraine. In March 2023, zavegepant nasal spray (ZAVZPRET™) received its first approval in the USA for the acute treatment of migraine with or without aura in adults. Clinical development of an oral formulation of zavegepant is currently underway. This article summarizes the milestones in the development of zavegepant leading to this first approval for the acute treatment of migraine with or without aura in adults.

Reversal of Peripheral Neuropathic Pain by the Small-Molecule Natural Product Narirutin via Block of Nav1.7 Voltage-Gated Sodium Channel

Neuropathic pain is a refractory chronic disease affecting millions of people worldwide. Given that present painkillers have poor efficacy or severe side effects, developing novel analgesics is badly needed. The multiplex structure of active ingredients isolated from natural products provides a new source for phytochemical compound synthesis. Here, we identified a natural product, Narirutin, a flavonoid compound isolated from the Citrus unshiu, showing antinociceptive effects in rodent models of neuropathic pain. Using calcium imaging, whole-cell electrophysiology, western blotting, and immunofluorescence, we uncovered a molecular target for Narirutin's antinociceptive actions. We found that Narirutin (i) inhibits Veratridine-triggered nociceptor activities in L4-L6 rat dorsal root ganglion (DRG) neurons, (ii) blocks voltage-gated sodium (Na_V) channels subtype 1.7 in both small-diameter DRG nociceptive neurons and human embryonic kidney (HEK) 293 cell line, (iii) does not affect tetrodotoxin-resistant (TTX-R) Na_V channels, and (iv) blunts the upregulation of Na_v1.7 in calcitonin gene-related peptide (CGRP)-labeled DRG sensory neurons after spared nerve injury (SNI) surgery. Identifying Na_v1.7 as a molecular target of Narirutin may further clarify the analgesic mechanism of natural flavonoid compounds and provide an optimal idea to produce novel selective and efficient analgesic drugs.

Immunologic aspects of migraine: A review of literature

Migraine headaches are highly prevalent, affecting 15% of the population. However, despite many studies to determine this disease's mechanism and efficient management, its pathophysiology has not been fully elucidated. There are suggested hypotheses about the possible mediating role of mast cells, immunoglobulin E, histamine, and cytokines in this disease. A higher incidence of this disease in allergic and asthma patients, reported by several studies, indicates the possible role of brain mast cells located around the brain vessels in this disease. The mast cells are more specifically within the dura and can affect the trigeminal nerve and cervical or sphenopalatine ganglion, triggering the secretion of substances that cause migraine. Neuropeptides such as calcitonin gene-related peptide (CGRP), neurokinin-A, neurotensin (NT), pituitary adenylate-cyclase-activating peptide (PACAP), and substance P (SP) trigger mast cells, and in response, they secrete pro-inflammatory and vasodilatory molecules such as interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) as a selective result of corticotropin-releasing hormone (CRH) secretion. This stress hormone contributes to migraine or intensifies it. Blocking these pathways using immunologic agents such as CGRP antibody, anti-CGRP receptor antibody, and interleukin-1 beta (IL-1β)/interleukin 1 receptor type 1 (IL-1R1) axis-related agents may be promising as potential prophylactic migraine treatments. This review is going to summarize the immunological aspects of migraine.

CGRP-Targeted Therapy for Episodic and Chronic Cluster Headache

PURPOSE OF REVIEW

Chronic cluster headache (CH) substantially affects patients' quality of life, and treatment remains challenging. The current article reviewed controlled studies for new treatment options targeting calcitonin gene-related peptide (CGRP) or its receptors in CH and discussed the current gaps and future directions for the treatment of chronic CH.

RECENT FINDINGS

Two anti-CGRP monoclonal antibodies (i.e., galcanezumab and fremanezumab) completed randomized-control trials for efficacy for the preventive treatment of episodic and chronic CH. Galcanezumab was effective for preventing episodic CH but not chronic CH. Fremanezumab was ineffective in preventing episodic and chronic CH. Studies for other anti-CGRP monoclonal antibodies and CGRP antagonists are still pending for results. There are no randomized controlled trials for CGRP-targeted therapies that showed efficacy for chronic CH prevention. The different responses to galcanezumab between episodic and chronic CH may be due to the study design, i.e., the allowance of concomitant preventive therapies in the chronic CH study but not in the episodic CH study. Another reason for the discrepancies is the different roles and sensitivity of CGRP in chronic CH.

Novel Migraine Therapies May Reduce Public and Personal Disadvantages for People with Migraine

The introduction of new drug classes for migraine, such as monoclonal antibodies that target the calcitonin gene-related peptide (CGRP) or its receptor and small-molecule antagonists of CGRP, have opened a new scenario in a large population of individuals suffering from migraines. The provision of an effective and safe therapy can help overcome the high social and personal costs together with the burden of this disease by offering social, work and economic recovery to the people affected by migraine. Whether the satisfaction of personal and collective unmet needs will be achieved in the vast majority of migraine sufferers now depends only on the efficiency of the organizational care structures dedicated to this socially impactful disease. This path will offer personal benefits and significant psychosocial relief that will help to reduce the enormous current healthcare expenditure necessary for the management of the huge number of individuals suffering from migraines. The new pharmacological classes for prevention must be applied as an interdiction to the chronic phase to express their full rehabilitation potential.