Nonclinical safety evaluation of erenumab, a CGRP receptor inhibitor for the prevention of migraine

Case series on monoclonal antibodies targeting calcitonin gene-related peptide in migraine patients during pregnancy: Enhancing safety data

BACKGROUND

Monoclonal antibodies targeting calcitonin gene-related peptide (CGRP-mAbs) are approved for adult migraine prevention but pose safety concerns in pregnancy. We assess the safety of CGRP-mAbs in the periconceptional period through a case series and literature review.

METHODS

Six migraine-diagnosed women received CGRP-mAbs; treatment ceased upon pregnancy. We collected data and conducted safety assessments. To provide a comprehensive context, we performed a literature review.

RESULTS

The series includes three erenumab, two fremanezumab and one galcanezumab case. A fremanezumab recipient experienced miscarriage; severe perinatal asphyxia linked to dystocia occurred with erenumab (140 mg). Database reviews revealed 63 spontaneous abortions, eight premature births, and seven birth defects among 286 World Health Organization and 65 European Medicines Agency cases. These rates align with untreated population rates.

CONCLUSIONS

CGRP-mAbs use in the periconceptional period does not lead to clinically significant increase in pregnancy-related pathology or adverse effects on newborns within our case series and the literature reviewed.

CGRP promotes osteogenic differentiation by regulating macrophage M2 polarization through HDAC6/AKAP12 signaling pathway

Aim: To determine the mechanism of Calcitonin gene-related peptide (CGRP) in bone healing.Materials & methods: Alkaline phosphatase (ALP) activity and inflammatory-factor levels were detected using ELISA. Osteogenic differentiation was assessed using Alizarin red staining technique. The interaction between histone deacetylase 6 (HDAC6) and A-kinase anchoring protein 12 (AKAP12) was investigated through Co- immunoprecipitation.Results: CGRP treatment promoted rat bone marrow-derived macrophages (BMDMs) M2 polarization. CGRP facilitated osteogenic differentiation by enhancing M2 polarization of BMDMs. Mechanistically, CGRP promoted AKAP12 acetylation to activate the extracellular regulated protein kinases pathway by HDAC6 inhibition.Conclusion: CGRP promoted M2 polarization of rat BMDMs and facilitated osteogenic differentiation through the HDAC6/AKAP12/extracellular regulated protein kinases signaling pathway, thereby promoting bone healing.

Blood pressure elevation in erenumab-treated patients with migraine: A retrospective real-world experience

BACKGROUND

Erenumab is a monoclonal antibody that targets the calcitonin gene-related peptide (CGRP) receptor and is approved for the preventative treatment of migraine in adults. CGRP is involved in the regulation of vasomotor tone under physiologic and pathologic conditions, including hypertension. While there has not been evidence of hypertension in preclinical models or clinical trials, post-marketing data suggest erenumab may be associated with hypertension. This led to a warning in the United States Food and Drug Administration prescribing information for erenumab.

OBJECTIVE

To determine the frequency of worsening blood pressure (BP) after initiation of erenumab in patients with migraine and how this is associated with hypertension.

METHODS

This is an observational retrospective cohort study evaluating patients at a tertiary headache or neurology department. Systolic and diastolic BPs were compared between the initial visit prior to initiation of erenumab, and follow-up visit while on erenumab. Worsening BP was defined as moving from a lower stage to a higher stage of BP, as defined by the American Heart Association. Serious adverse vascular events were also recorded.

RESULTS

A total of 335 patients were included in the final analysis (mean [SD] age of 45.7 [14.40] years, 83.9% [281/335] female). At baseline, 20.9% (70/335) of patients had a prior diagnosis of hypertension. The median (interquartile range) time to follow-up appointment from initial appointment was 20.5 (13.3-35.3) weeks. The mean (SD) BP at baseline was systolic 124.7 (15) mmHg and diastolic 77 (11) mmHg, and at follow-up was systolic 124.0 (15) mmHg and diastolic 77.8 (9) mmHg. Overall, 23.3% (78/335) of all patients had worsening BP, whereas 13/225 (3.9%) patients had improvement in their BP. Patients with atrial fibrillation were more likely to develop worsening BP (odds ratio, 4.9, 95% confidence interval 1.12-21.4; p = 0.035). There was no association between worsening BP and pre-existing hypertension, sex, body mass index, or age. One patient had non-ST elevation myocardial infarction attributed to a hypertensive emergency while on erenumab.

CONCLUSION

We found that 23.3% of patients initiated on erenumab may have developed worsening BP, suggesting the need for BP monitoring in patients initiated on erenumab.

Pharmacology of erenumab in human isolated coronary and meningeal arteries: Additional effect of gepants on top of a maximum effect of erenumab

BACKGROUND AND PURPOSE

Multiple drugs targeting the calcitonin gene-related peptide (CGRP) receptor have been developed for migraine treatment. Here, the effect of the monoclonal antibody erenumab on CGRP-induced vasorelaxation was investigated in human isolated blood vessels, as well as the effect of combining erenumab with the small molecule drugs, namely rimegepant, olcegepant, or sumatriptan.

EXPERIMENTAL APPROACH

Concentration-response curves to CGRP, adrenomedullin or pramlintide were constructed in human coronary artery (HCA) and human middle meningeal artery (HMMA) segments, incubated with or without erenumab and/or olcegepant. pA2 or pKb values were calculated to determine the potency of erenumab in both tissues. To study whether acutely acting antimigraine drugs exerted additional CGRP-blocking effects on top of erenumab, HCA segments were incubated with a maximally effective concentration of erenumab (3 μM), precontracted with KCl and exposed to CGRP, followed by rimegepant, olcegepant, or sumatriptan in increasing concentrations.

KEY RESULTS

Erenumab shifted the concentration-response curve to CGRP in both vascular tissues. However, in HCA, the Schild plot slope was significantly smaller than unity, whereas this was not the case in HMMA, indicating different CGRP receptor mechanisms in these tissues. In HCA, rimegepant, olcegepant and sumatriptan exerted additional effects on CGRP on top of a maximal effect of erenumab.

CONCLUSIONS AND IMPLICATIONS

Gepants have additional effects on top of erenumab for CGRP-induced relaxation and could be effective in treating migraine attacks in patients already using erenumab as prophylaxis.

Health equity, care access and quality in headache - part 2

BACKGROUND

Headache disorders are a global public health concern affecting diverse populations. This review examines headache service organizations in low-, middle-, and high-income countries. It addresses global challenges in pharmacological headache treatment, with a focus on safety, tolerability, reproductive and child health, and outlines disparities in accessing innovative treatments worldwide.

MAIN BODY

Organized headache services are essential due to the wide prevalence and varying severity of headache disorders. The tiered headache service model is globally recognized, although its implementation varies based on financial and workforce considerations. Headache burden affects well-being, causing disability, economic challenges, and work limitations, irrespective of location or income. All nations still require improved diagnosis and treatment, and the majority of countries face obstacles including limited access, awareness, economic barriers, and inadequate health policies. Provided adequate internet availability, telemedicine could help improve health equity by expanding access to headache care, since it can offer patients access to services without lengthy waiting times or extensive travel and can provide healthcare unavailable in underserved areas due to staff shortages. Numerous health disparities restrict global access to many headache medications, especially impacting individuals historically excluded from randomized controlled trials, such as those with cardiovascular and cerebrovascular conditions, as well as pregnant women. Furthermore, despite advancements in researching migraine treatments for young patients, the options for treatment remain limited. Access to headache treatment relies on factors like medication availability, approval, financial coverage, and healthcare provider expertise. Inadequate public awareness leads to neglect by policymakers and undertreatment by patients and healthcare providers. Global access discrepancies are exacerbated by the introduction of novel disease-specific medications, particularly impacting Asian, African, and Latin American nations excluded from clinical trials. While North America and Europe experience broad availability of migraine treatments, the majority of countries worldwide lack access to these therapies.

CONCLUSIONS

Healthcare disparities, treatment access, and medication availability are concerning issues in headache medicine. Variations in national healthcare systems impact headache management, and costly innovative drugs are widening these gaps. Healthcare practitioners and experts should acknowledge these challenges and work towards minimizing access barriers for equitable global headache care in the future.

Consensus-Based Recommendations on the Use of CGRP-Based Therapies for Migraine Prevention in the UAE

INTRODUCTION

Migraine is a common debilitating neurological disorder affecting a large proportion of the general population. Calcitonin gene-related peptide (CGRP), a 37-amino acid neuropeptide, plays a key role in the pathophysiology of migraine, and the development of therapies targeting the anti-CGRP pathway has revolutionized the field of migraine treatment.

METHODS

An expert task force of neurologists in the United Arab Emirates (UAE) developed and critically assessed recommendations on the use of CGRP-based therapies in migraine treatment and management in the UAE, based on available published literature. A consensus was reached for each statement by means of an open-voting process, based on a predefined agreement level of at least 60%.

RESULTS

The consensus recommendations advocate the need for guidelines for the appropriate use of CGRP-based therapies by defining patient cohorts and appropriate monitoring of therapeutic response as well as standardizing the initiation, assessment, and cessation of treatment. The consensus recommendations were primarily formulated on the basis of international studies, because of the limited availability of regional and local data. As such, they may also act as guidelines for global healthcare providers.

CONCLUSIONS

These are the first consensus recommendations for the UAE that address the use of CGRP-based therapies in the treatment and management of migraine, integrating both clinical evidence and medical expertise to enhance clinical judgment and decision-making.

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.

CGRP physiology, pharmacology, and therapeutic targets: migraine and beyond

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse physiological functions. Its two isoforms (α and β) are widely expressed throughout the body in sensory neurons as well as in other cell types, such as motor neurons and neuroendocrine cells. CGRP acts via at least two G protein-coupled receptors that form unusual complexes with receptor activity-modifying proteins. These are the CGRP receptor and the AMY1 receptor; in rodents, additional receptors come into play. Although CGRP is known to produce many effects, the precise molecular identity of the receptor(s) that mediates CGRP effects is seldom clear. Despite the many enigmas still in CGRP biology, therapeutics that target the CGRP axis to treat or prevent migraine are a bench-to-bedside success story. This review provides a contextual background on the regulation and sites of CGRP expression and CGRP receptor pharmacology. The physiological actions of CGRP in the nervous system are discussed, along with updates on CGRP actions in the cardiovascular, pulmonary, gastrointestinal, immune, hematopoietic, and reproductive systems and metabolic effects of CGRP in muscle and adipose tissues. We cover how CGRP in these systems is associated with disease states, most notably migraine. In this context, we discuss how CGRP actions in both the peripheral and central nervous systems provide a basis for therapeutic targeting of CGRP in migraine. Finally, we highlight potentially fertile ground for the development of additional therapeutics and combinatorial strategies that could be designed to modulate CGRP signaling for migraine and other diseases.

Evaluation of vascular risk in patients with migraine with and without aura treated with erenumab: Post hoc analysis of pooled long-term clinical trial data

OBJECTIVE

To assess cardiovascular (CV) safety of erenumab in clinical trial patients associated with degree of CV risk.

BACKGROUND

Hypertension has been considered a theoretical risk associated with the inhibition of the calcitonin gene-related peptide pathway in migraine management, particularly in a patient population with pre-existing CV risk factors.

METHODS

Data pooled from four double-blind, randomized trials were used to assess blood pressure (BP) changes and CV safety in patients grouped based on 10-year risk of cardiac, cerebrovascular, and peripheral artery disease as no-risk-factors, low-risk (>0% to ≤10%), moderate-risk (>10% to ≤20%), and high-risk (>20%) categories. CV safety was assessed as ischemic cardiovascular and cerebrovascular adverse events (ICCAE).

RESULTS

There was no apparent difference between placebo- (N = 1032) and erenumab-treatment groups (70 mg, N = 885; 140 mg, N = 504) in clinical worsening of BP category from baseline to Months 1-3 (14% [143/1032] placebo vs. 13% [114/885] and 14% [71/504] for erenumab 70 and 140 mg, respectively) regardless of baseline BP category. The adverse event (AE) profile of erenumab was similar across CV risk categories throughout the long-term analysis. Erenumab-treated patients with high and moderate 10-year CV risk (N = 107) did not experience any ICCAEs during the double-blind treatment period; there was a single ICCAE (a cerebral dural venous sinus thrombosis) observed in the low-risk erenumab group (N = 273). There were no increases in AEs during the long-term extensions of up to 5 years (N = 2499; 3482 patient-years of exposure to erenumab) with exposure-adjusted incidence rates of cardio/cerebrovascular disorder AEs of 0.4, 0.5, 0.0, and 1.1 (per 100 patient-years) for no risk factor (N = 1805), low (N = 492), moderate (N = 121), and high (N = 81) 10-year CV risk groups, respectively.

CONCLUSIONS

Ischemic CV and cerebrovascular AEs were uncommon and the incidence rates were similar across the 10-year CV risk categories. This analysis helps provide more detail on the CV safety of erenumab.

Safety of drugs used for the treatment of migraine during pregnancy: a narrative review

INTRODUCTION

Migraine is common in females of childbearing age and negatively impacts quality of life. The majority of those with migraine who become pregnant see an improvement in their condition but not all do. Providing evidence-based recommendations for the pharmacological management of migraine in pregnancy is challenging.

AREAS COVERED

This narrative review provides an update on the safety of drugs used for migraine in pregnancy. National and international guidelines on the management of episodic migraine in adults were used to select the drugs of relevance to pregnant women. The final list of drugs was chosen by a pain specialist who categorized them according to drug class and use in acute management or prevention. PubMed was searched from inception to 31st July 2022 for evidence on drug safety.

EXPERT OPINION

Obtaining high-quality drug safety data in pregnant migraineurs is difficult not least because exposing a fetus to research-related risks is often considered unethical. There is reliance on observational studies which often group drugs together and lack specificities pertinent to drug prescribing like timing, dosing and duration. Improved statistical tools, study designs and the creation of international collaborative frameworks are ways to advance knowledge on drug safety in pregnancy.

Characterization of Antibodies against Receptor Activity-Modifying Protein 1 (RAMP1): A Cautionary Tale

Calcitonin gene-related peptide (CGRP) is a key component of migraine pathophysiology, yielding effective migraine therapeutics. CGRP receptors contain a core accessory protein subunit: receptor activity-modifying protein 1 (RAMP1). Understanding of RAMP1 expression is incomplete, partly due to the challenges in identifying specific and validated antibody tools. We profiled antibodies for immunodetection of RAMP1 using Western blotting, immunocytochemistry and immunohistochemistry, including using RAMP1 knockout mouse tissue. Most antibodies could detect RAMP1 in Western blotting and immunocytochemistry using transfected cells. Two antibodies (844, ab256575) could detect a RAMP1-like band in Western blots of rodent brain but not RAMP1 knockout mice. However, cross-reactivity with other proteins was evident for all antibodies. This cross-reactivity prevented clear conclusions about RAMP1 anatomical localization, as each antibody detected a distinct pattern of immunoreactivity in rodent brain. We cannot confidently attribute immunoreactivity produced by RAMP1 antibodies (including 844) to the presence of RAMP1 protein in immunohistochemical applications in brain tissue. RAMP1 expression in brain and other tissues therefore needs to be revisited using RAMP1 antibodies that have been comprehensively validated using multiple strategies to establish multiple lines of convincing evidence. As RAMP1 is important for other GPCR/ligand pairings, our results have broader significance beyond the CGRP field.

The use of erenumab for migraine prophylaxis during pregnancy: A case report and narrative review

OBJECTIVE

To report a case of a woman who continued erenumab for migraine prophylaxis throughout her pregnancy and to review the literature for pregnancy safety data for the calcitonin gene-related peptide (CGRP) receptor and ligand-directed therapies currently approved for migraine prophylaxis in the United States.

BACKGROUND

Migraine is a common headache disorder that can be significantly disabling. Many people experiencing migraine seek out preventative therapies to improve their quality of life. Unfortunately, currently approved prophylactic agents may not be safe to use during pregnancy, potentially limiting the use of these agents in women of childbearing potential. As the newest class of prophylactic agents for migraine, CGRP agents have limited pregnancy safety data in humans.

METHODS

A review of the literature was conducted through the PubMed database using the terms pregnancy and either erenumab, fremanezumab, galcanezumab, eptinezumab, rimegepant, or atogepant. Additional sources of information such as prescribing information, assessment reports submitted to the European Medicines Agency (EMA), and manufacturer data were sought.

RESULTS

One case report was found in the literature documenting a human pregnancy with no adverse effects in the baby after exposure to erenumab. However, the last dose was administered in the second week of pregnancy and discontinued thereafter. The evaluation of 92 safety reports describing maternal exposure prior to or during pregnancy to either erenumab, galcanezumab, or fremanezumab was located. Incidence of miscarriage and congenital anomalies appear to be similar to rates in the general population.

CONCLUSIONS

The use of erenumab during pregnancy in our patient resulted in no known harm to the child. This case is unique in that the mother continued to receive erenumab throughout the pregnancy. Safety data is lacking regarding the use of these agents during pregnancy, despite their frequent use in women of childbearing potential.

European Headache Federation guideline on the use of monoclonal antibodies targeting the calcitonin gene related peptide pathway for migraine prevention - 2022 update

Background

A previous European Headache Federation (EHF) guideline addressed the use of monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway to prevent migraine. Since then, randomized controlled trials (RCTs) and real-world evidence have expanded the evidence and knowledge for those treatments. Therefore, the EHF panel decided to provide an updated guideline on the use of those treatments.

Methods

The guideline was developed following the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach. The working group identified relevant questions, performed a systematic review and an analysis of the literature, assessed the quality of the available evidence, and wrote recommendations. Where the GRADE approach was not applicable, expert opinion was provided.

Results

We found moderate to high quality of evidence to recommend eptinezumab, erenumab, fremanezumab, and galcanezumab in individuals with episodic and chronic migraine. For several important clinical questions, we found not enough evidence to provide evidence-based recommendations and guidance relied on experts’ opinion. Nevertheless, we provided updated suggestions regarding the long-term management of those treatments and their place with respect to the other migraine preventatives.

Conclusion

Monoclonal antibodies targeting the CGRP pathway are recommended for migraine prevention as they are effective and safe also in the long-term.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01431-x.

Platelet P2Y12 Inhibitor in the Treatment and Prevention of Migraine: A Systematic Review and Meta-Analysis

There have been speculation and research linking migraine with abnormalities of platelet aggregation and activation. The role of the P2Y12 platelet inhibitor in the treatment of migraine has not been established. We aim to evaluate the efficacy of the platelet P2Y12 inhibitor in the treatment of migraine and prevention of new-onset migraine headache (MHA) following transcatheter atrial septal defect closure (ASDC). We searched the PubMed, Web of Science, and Cochrane Library databases for relevant studies. The primary outcomes were the headache responder rate and the rate of new-onset migraine attacks following ASDC. Four studies for a total of 262 migraine patients with or without patent foramen ovale (PFO) and three studies involving 539 patients with antiplatelet treatment in the prevention of new-onset migraine following ASDC were included. The pooled responder rate of the P2Y12 inhibitor for migraine was 0.64 (95% CI: 0.43 to 0.81). For patients who underwent ASDC, the use of antiplatelet regimens including the P2Y12 inhibitor, compared with regimens excluding P2Y12 inhibitor, resulted in a lower rate of new-onset migraine (OR: 0.41, 95% CI: 0.22 to 0.77, P = 0.005). We concluded that the P2Y12 platelet inhibitor may have a primary prophylactic role in migraine patients with or without PFO and prevent new-onset MHA after ASDC. The responsiveness of the P2Y12 inhibitor could help select candidates who would benefit from PFO closure. It warrants further large-scale research to explore the role of the P2Y12 inhibitor, particularly in a proportion of migraine patients.

Risk of hypertension in erenumab-treated patients with migraine: Analyses of clinical trial and postmarketing data

Objective

To assess the risk of hypertension in patients with migraine who received erenumab in clinical trials and in the postmarketing setting.

Background

Erenumab is a monoclonal antibody for migraine prevention that targets the calcitonin gene‐related peptide (CGRP) receptor. Hypertension is a theoretical risk for inhibitors of the CGRP pathway. Although no evidence of an association between erenumab treatment and hypertension was observed during the clinical development program, adverse events (AEs) of hypertension have been identified in the postmarketing setting.

Methods

Safety data from four phase 2 and phase 3 clinical trials were used to perform a pooled analysis of hypertension AEs in patients with migraine receiving erenumab. Postmarketing AEs of hypertension were identified from the Amgen Global Safety database from May 17, 2018, through January 31, 2020.

Results

In the pooled analysis of clinical trials, hypertension AEs (placebo, 9/1043 [0.9%]; erenumab 70 mg, 7/893 [0.8%]; erenumab 140 mg, 1/507 [0.2%]) and percentage of patients initiating medication to treat hypertension (12/1043 [1.2%], 7/893 [0.8%], 1/507 [0.2%], respectively) were similar across treatment groups. A total of 362 AEs of hypertension were identified from the postmarketing setting, 26.2% (95/362) of which were serious, >245,000 patient‐years of exposure. The exposure‐adjusted incidence of hypertension was 0.144 per 100 patient‐years.

Conclusions

Clinical trials did not demonstrate an increased risk of hypertension with erenumab compared with placebo, and AE rates of hypertension reported with erenumab in the postmarketing setting were generally low. Additional data are needed to fully characterize the extent to which hypertension is a risk associated with erenumab.

Safety and tolerability evaluation of erenumab for the preventive treatment of migraine

Introduction: Erenumab, a monoclonal antibody targeting the receptor of calcitonin gene related peptide (CGRP), is the first disease-specific and mechanism-based treatment approved for the prevention of migraine. Although the safety and tolerability data from randomized trials are clear, the physiological effects of CGRP rise reasonable concerns. We aimed to evaluate the current evidence for safety and tolerability related to erenumab use in migraine. Areas covered: This review outlines the severe adverse events (AEs), common AEs, AEs leading to treatment discontinuation and AEs of special interest, reported in all phase 2, phase 3, open label, and observational studies with erenumab in migraine. Individual safety reports were also included in the systematic review of evidence. Expert opinion: No safety and tolerability flags were detected in this review. The most common AE are local skin reactions and constipation. No severe AEs, or frequent AEs leading to treatment discontinuation were detected. Treatment is well tolerated. The only AE of interest that may play a role in decision making and treatment monitoring is constipation. These findings are in line with previous safety reports, further highlighting the substantial tolerability and safety profile of the modern anti-CGRP monoclonal antibodies for the prevention of migraine.

Monoaminergic Receptors as Modulators of the Perivascular Sympathetic and Sensory CGRPergic Outflows

Blood pressure is a highly controlled cardiovascular parameter that normally guarantees an adequate blood supply to all body tissues. This parameter is mainly regulated by peripheral vascular resistance and is maintained by local mediators (i.e., autacoids), and by the nervous and endocrine systems. Regarding the nervous system, blood pressure can be modulated at the central level by regulating the autonomic output. However, at peripheral level, there exists a modulation by activation of prejunctional monoaminergic receptors in autonomic- or sensory-perivascular fibers. These modulatory mechanisms on resistance blood vessels exert an effect on the release of neuroactive substances from the autonomic or sensory fibers that modify blood pressure. Certainly, resistance blood vessels are innervated by perivascular: (i) autonomic sympathetic fibers (producing vasoconstriction mainly by noradrenaline release); and (ii) peptidergic sensory fibers [producing vasodilatation mainly by calcitonin gene-related peptide (CGRP) release]. In the last years, by using pithed rats, several monoaminergic mechanisms for controlling both the sympathetic and sensory perivascular outflows have been elucidated. Additionally, several studies have shown the functions of many monoaminergic auto-receptors and hetero-receptors expressed on perivascular fibers that modulate neurotransmitter release. On this basis, the present review: (i) summarizes the modulation of the peripheral vascular tone by adrenergic, serotoninergic, dopaminergic, and histaminergic receptors on perivascular autonomic (sympathetic) and sensory fibers, and (ii) highlights that these monoaminergic receptors are potential therapeutic targets for the development of novel medications to treat cardiovascular diseases (with some of them explored in clinical trials or already in clinical use).

Extreme ecchymoses in a migraine patient using concomitant treatment with calcitonin gene-related peptide receptor antibodies and fish oil supplements: a case report

Background

Erenumab, a monoclonal antibody against the calcitonin gene-related peptide (CGRP) receptor, is registered for migraine prevention. Compared to other conventional migraine prevention medicines (i.e. topiramate, betablockers and amitriptyline) erenumab has better tolerability. Impaired hemostasis has not been reported previously. Here, we report the first case of an increased tendency to bruise in a migraine patient treated with erenumab.

Case presentation

A 41-year old female migraine patient was treated with erenumab for 12 months, which led to a significant reduction of headache and migraine days. Three months after treatment start, she experienced increased tendency to bruise leading to extreme ecchymosis after 4 months treatment. Platelet counts and aggregation, thromboelastography, activated partial thromboplastin time (APTT) and international normalized ratio (INR) were all normal. Thorough interview revealed intake of fish oil supplements for many years prior to treatment. The increased tendency to bruise subsided after discontinuation of fish oil supplements.

Conclusion

The combination of fish oil supplements and erenumab may cause increased tendency to bruise. Erenumab has no effect on the platelets per se but may cause impaired wound healing by suppression of CGRP. Thus, small and unnoticeable bruises may be aggravated instead in patients with tendency to bruise caused by for instance fish oil supplements.

Migraine therapeutics differentially modulate the CGRP pathway

Background

The clinical efficacy of migraine therapeutic agents directed towards the calcitonin-gene related peptide (CGRP) pathway has confirmed the key role of this axis in migraine pathogenesis. Three antibodies against CGRP – fremanezumab, galcanezumab and eptinezumab – and one antibody against the CGRP receptor, erenumab, are clinically approved therapeutics for the prevention of migraine. In addition, two small molecule CGRP receptor antagonists, ubrogepant and rimegepant, are approved for acute migraine treatment. Targeting either the CGRP ligand or receptor is efficacious for migraine treatment; however, a comparison of the mechanism of action of these therapeutic agents is lacking in the literature.

Methods

To gain insights into the potential differences between these CGRP pathway therapeutics, we compared the effect of a CGRP ligand antibody (fremanezumab), a CGRP receptor antibody (erenumab) and a CGRP receptor small molecule antagonist (telcagepant) using a combination of binding, functional and imaging assays.

Results

Erenumab and telcagepant antagonized CGRP, adrenomedullin and intermedin cAMP signaling at the canonical human CGRP receptor. In contrast, fremanezumab only antagonized CGRP-induced cAMP signaling at the human CGRP receptor. In addition, erenumab, but not fremanezumab, bound and internalized at the canonical human CGRP receptor. Interestingly, erenumab also bound and internalized at the human AMY₁ receptor, a CGRP receptor family member. Both erenumab and telcagepant antagonized amylin-induced cAMP signaling at the AMY₁ receptor while fremanezumab did not affect amylin responses.

Conclusion

The therapeutic effect of agents targeting the CGRP ligand versus receptor for migraine prevention (antibodies) or acute treatment (gepants) may involve distinct mechanisms of action. These findings suggest that differing mechanisms could affect efficacy, safety, and/or tolerability in migraine patients.

Anti-migraine agents from an immunological point of view

The new wave of anti-migraine agents is nothing less than a milestone in our battle to manage this devastating disease. However, concerns have recently increased regarding the safety of these drugs. CGRP, while known as a potent vasodilator, is also a key neural and immune modulator. The roles of CGRP in immune determination, have been studied in depth, with particular focus on its functional significance with respect to common immune challenges i.e., bacterial, viral, fungal and parasitic infections. This review discusses many potential areas of concern in regard to blocking CGRP function and its potential influence on immune milieus during infection, and the risk of adverse effects. Finally, this review recommends specific measures to be taken into consideration when administering anti-CGRP/CGRPR agents.

Changing levels of sex hormones and calcitonin gene-related peptide (CGRP) during a woman's life: Implications for the efficacy and safety of novel antimigraine medications

Migraine is a neurovascular disorder that is three times more prevalent in women than in men and represents a large socio-economic burden. Therefore, the development of new preventive medications is an urgent matter. Currently, calcitonin gene-related peptide (CGRP), a neuropeptide released from trigeminal fibres, is an important target for migraine treatment. Accordingly, antibodies directed against CGRP or its receptor, as well as small-molecule CGRP receptor antagonists, have been developed for the prophylactic and acute treatment of migraine. Results from clinical phase III trials show a significant decrease in migraine days and relatively mild side-effects. However, CGRP is not only present in the trigeminal nerve, but it is also abundant in perivascular nerve fibres. Moreover, CGRP levels and hormones vary between sexes and during different life stages, and hormones affect CGRP, with a seemingly greater role for CGRP in females. In this review we discuss whether these aspects could be associated with differences in response and efficacy of drugs interfering with the CGRP pathway. Furthermore, CGRP has been described as playing a protective role in ischemic events, and CGRP seems to play a larger role in cardiac ischemic events in female patients. As cardiovascular risk is increased in female migraine patients and also increases significantly in females after menopause, further research into the risk of blocking CGRP in these patients is needed.

Optimal treatment strategy of fremanezumab in migraine prevention: a systematic review with network meta-analysis of randomized clinical trials

Identifying the optimal fremanezumab treatment strategy is crucial in treating patients with migraines. The optimal strategy was investigated by assessing the cumulative 50% reduction rate (50%CRR), cumulative 75% reduction rate (75%CRR), reduction in the number of migraine days, treatment-related adverse events, and serious adverse events in patients treated with fremanezumab 225 mg monthly (225 mg), 675 mg monthly (675 mg), 900 mg monthly (900 mg), a single high dose of 675 mg (S675mg), 675 mg at baseline with 225 mg monthly (675/225 mg), and placebo. Biomedical databases were searched for randomized controlled trials on this topic, and data were individually extracted. Risk ratios and mean differences were used to present the pooled results. The surface under the cumulative ranking curve (SUCRA) was used to determine the effects of the medication strategies of fremanezumab. Five trials (n = 3404) were used to form a six-node network meta-analysis. All fremanezumab medication strategies displayed significantly higher cumulative 50% reduction rates than the placebo. The SUCRA revealed that treatment with 675 mg yielded the highest 50%CRR value (mean rank = 2.5). S675 mg was the only treatment with significantly higher 75%CRR reduction rate than placebo, whereas the SUCRA for 225 mg displayed the highest mean rank (2.2). Moreover, 225 mg (mean rank = 2.2) and S675 mg (mean rank = 2.2) presented lower probabilities of serious adverse events. Collectively, S675mg and 225 mg exhibited the optimal balance between efficacy and safety within three months. Long-term efficacy and safety remain unclear, and future studies should further evaluate the long-term outcomes.

The neuropeptide calcitonin gene-related peptide alpha is essential for bone healing

Background

Impaired fracture healing represents an ongoing clinical challenge, as treatment options remain limited. Calcitonin gene-related peptide (CGRP), a neuropeptide targeted by emerging anti-migraine drugs, is also expressed in sensory nerve fibres innervating bone tissue.

Method

Bone healing following a femoral osteotomy stabilized with an external fixator was analysed over 21 days in αCGRP-deficient and WT mice. Bone regeneration was evaluated by serum analysis, µCT analysis, histomorphometry and genome-wide expression analysis. Bone-marrow-derived osteoblasts and osteoclasts, as well as the CGRP antagonist olcegepant were employed for mechanistic studies.

Findings

WT mice with a femoral fracture display increased CGRP serum levels. αCGRP mRNA expression after skeletal injury is exclusively induced in callus tissue, but not in other organs. On protein level, CGRP and its receptor, calcitonin receptor-like receptor (CRLR) complexing with RAMP1, are differentially expressed in the callus during bone regeneration. On the other hand, αCGRP-deficient mice display profoundly impaired bone regeneration characterised by a striking reduction in the number of bone-forming osteoblasts and a high rate of incomplete callus bridging and non-union. As assessed by genome-wide expression analysis, CGRP induces the expression of specific genes linked to ossification, bone remodeling and adipogenesis. This suggests that CGRP receptor-dependent PPARγ signaling plays a central role in fracture healing.

Interpretation

This study demonstrates an essential role of αCGRP in orchestrating callus formation and identifies CGRP receptor agonism as a potential approach to stimulate bone regeneration. Moreover, as novel agents blocking CGRP or its receptor CRLR are currently introduced clinically for the treatment of migraine disorders, their potential negative impact on bone regeneration warrants clinical investigation.

Funding

This work was funded by grants from the Else-Kröner-Fresenius-Stiftung (EKFS), the Deutsche Forschungsgemeinschaft (DFG), and the Berlin Institute of Health (BIH).

Pharmacological treatment of migraine: CGRP and 5-HT beyond the triptans

Migraine is a highly disabling neurovascular disorder characterized by a severe headache (associated with nausea, photophobia and/or phonophobia), and trigeminovascular system activation involving the release of calcitonin-gene related peptide (CGRP). Novel anti-migraine drugs target CGRP signaling through either stimulation of 5-HT1F receptors on trigeminovascular nerves (resulting in inhibition of CGRP release) or direct blockade of CGRP or its receptor. Lasmiditan is a highly selective 5-HT1F receptor agonist and, unlike the triptans, is devoid of vasoconstrictive properties, allowing its use in patients with cardiovascular risk. Since lasmiditan can actively penetrate the blood-brain barrier, central therapeutic as well as side effects mediated by 5-HT1F receptor activation should be further investigated. Other novel anti-migraine drugs target CGRP signaling directly. This neuropeptide can be targeted by the monoclonal antibodies eptinezumab, fremanezumab and galcanezumab, or by CGRP-neutralizing L-aptamers called Spiegelmers. The CGRP receptor can be targeted by the monoclonal antibody erenumab, or by small-molecule antagonists called gepants. Currently, rimegepant and ubrogepant have been developed for acute migraine treatment, while atogepant is studied for migraine prophylaxis. Of these drugs targeting CGRP signaling directly, eptinezumab, erenumab, fremanezumab, galcanezumab, rimegepant and ubrogepant have been approved for clinical use, while atogepant is in the last stage before approval. Although all of these drugs seem highly promising for migraine treatment, their safety should be investigated in the long-term. Moreover, the exact mechanism(s) of action of these drugs need to be elucidated further, to increase both safety and efficacy and to increase the number of responders to the different treatments, so that all migraine patients can satisfactorily be treated.

A review of antibody-based therapeutics targeting G protein-coupled receptors: an update

INTRODUCTION

G protein-coupled receptors (GPCRs) play key roles in many biological functions and are linked to many diseases across all therapeutic areas. As such, GPCRs represent a significant opportunity for antibody-based therapeutics.

AREAS COVERED

The structure of the major GPCR families is summarized in the context of choice of antigen source employed in the drug discovery process and receptor biology considerations which may impact on targeting strategies. An overview of the therapeutic GPCR-antibody target landscape and the diversity of current therapeutic programs is provided along with summary case studies for marketed antibody drugs or those in advanced clinical studies. Antibodies in early clinical studies and the emergence of next-generation modalities are also highlighted.

EXPERT OPINION

The GPCR-antibody pipeline has progressed significantly with a number of technical developments enabling the successful resolution of some of the challenges previously encountered and this has contributed to the growing interest in antibody-based therapeutics addressing this target class.

Migraine and other headache disorders in pregnancy

Migraine prevalence is three times higher in women than in men during fertile years, which is mainly due to sex hormone differences. The majority of women suffering from migraine without aura report improvement of their migraine attacks during pregnancy. Migraine attacks with aura can also improve during pregnancy, but more often remain the same or worsen. Anovulation caused by lactation is generally associated with a decrease in migraine attacks in breastfeeding women. This chapter describes the current knowledge on acute and prophylactic treatment options of migraine and other primary headache disorders during pregnancy and lactation. Further, clinical profiles of secondary headaches during pregnancy and the postpartum period are summarized.

Long-term tolerability and nonvascular safety of erenumab, a novel calcitonin gene-related peptide receptor antagonist for prevention of migraine: A pooled analysis of four placebo-controlled trials with long-term extensions

BACKGROUND

Efficacy and safety of erenumab have been evaluated in a comprehensive clinical development program resulting in approval for migraine prevention in over 40 countries to date.

METHODS

This integrated safety analysis included four double-blind randomized trials and their extensions (up to three-plus years). Safety endpoints included exposure-adjusted patient incidences of adverse events, serious adverse events, and anti-erenumab antibodies.

RESULTS

In all, 2375 of the patients randomized across the four studies received at least one dose of erenumab (70 mg or 140 mg), with cumulative exposure of 2641.2 patient-years. Exposure-adjusted adverse event rates during the double-blind treatment phase were similar to placebo, with the exception of injection-site reactions (17.1 vs. 10.8 per 100 patient-years), constipation (7.0 vs. 3.8 per 100 patient-years), and muscle spasm (2.3 vs. 1.2 per 100 patient-years). During the long-term extensions, adverse events reported were similar to those observed during the double-blind treatment phase, and rates of injection site reactions, constipation, and muscle spasm were reported at lower rates than in the double-blind treatment phase. There were two deaths reported, both confounded by pre-existing conditions.

CONCLUSIONS

This pooled safety analysis revealed a favorable and stable adverse event profile over time for erenumab with more than three years of exposure.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01952574, NCT02483585, NCT02456740, NCT02066415, and NCT02174861.

Characterisation of vasodilatory responses in the presence of the CGRP receptor antibody erenumab in human isolated arteries

BACKGROUND

Migraine is associated with activation of the trigeminovascular system, release of calcitonin gene-related peptide (CGRP) and dilation of dural arteries. Novel treatments target calcitonin gene-related peptide or its receptor, which are present in all vascular beds, raising cardiovascular concerns. Erenumab is a human CGRP-receptor antibody approved for the prophylactic treatment of migraine.

METHODS

We characterised the relaxant responses to CGRP in the absence and presence of erenumab (1 μM) in isolated human middle meningeal, internal mammary and (proximal and distal) coronary arteries. Furthermore, in human internal mammary arteries from cardiovascularly-compromised patients, we assessed the pharmacological specificity of erenumab by investigating whether the vasodilatory responses to acetylcholine, sodium nitroprusside, pituitary adenylate cyclase activating polypeptide-38 (PACAP), vasoactive intestinal peptide and nicardipine, along with the vasoconstrictor responses to dihydroergotamine, were modified by erenumab.

RESULTS

Calcitonin gene-related peptide induced concentration-dependent vasodilatory responses in all vessels studied that were significantly antagonised by erenumab. In human internal mammary arteries from cardiovascularly-compromised patients, the responses to acetylcholine, sodium nitroprusside, PACAP, vasoactive intestinal peptide, nicardipine and dihydroergotamine were unaffected by erenumab.

CONCLUSION

Erenumab inhibits calcitonin gene-related peptide-induced vasodilatory responses in human middle meningeal arteries, human internal mammary arteries and human coronary arteries. Moreover, erenumab shows functional specificity as no interaction was observed with the relaxant responses to several vasodilators, nor the dihydroergotamine-dependent vasoconstrictor responses.