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

Long-Term Outcome After Discontinuation of CGRP-Targeting Therapy for Migraine

PURPOSE OF REVIEW

Calcitonin gene-related peptide (CGRP)-targeting agents are potential candidates for disease-modifying migraine drugs. However, most studies on CGRP-targeting agents have assessed efficacy outcomes rather than long-term effects after discontinuation. This review aimed to synthesize and scrutinize the latest clinical data on the outcomes after the discontinuation of CGRP-targeting therapy in patients with episodic and chronic migraine, with a particular focus on chronic migraine.

RECENT FINDINGS

Real-world studies involving patients with migraine have reported consistent findings of worsened headache frequency and quality of life after the discontinuation of CGRP monoclonal antibodies (CGRP mAbs). Although many patients maintain improvements for up to 4 months after discontinuation compared to baseline (before starting CGRP mAbs), no studies have evaluated the effects of stopping treatment for > 5 months, which is the five-half-life of CGRP mAbs. Several studies have suggested that patients treated with CGRP receptor mAbs experience more rapid deterioration than those treated with CGRP ligand mAbs after discontinuing CGRP mAbs. The results of real-world studies suggest that for many patients with migraine, the benefits of CGRP mAbs diminish months after discontinuation. Therefore, anti-CGRP therapies may not be considered disease-modifying. However, the comprehensive assessment of the disease-modifying potential of these drugs requires studies with extended treatment and cessation durations.

Pharmacologic characterization of atogepant: A potent and selective calcitonin gene-related peptide receptor antagonist

BACKGROUND

The trigeminal sensory neuropeptide calcitonin gene-related peptide (CGRP) is identified as an essential element in migraine pathogenesis.

METHODS

In vitro and in vivo studies evaluated pharmacologic properties of the CGRP receptor antagonist atogepant. Radioligand binding using 125I-CGRP and cyclic adenosine monophosphate (cAMP) accumulation assays were conducted in human embryonic kidney 293 cells to assess affinity, functional potency and selectivity. Atogepant in vivo potency was assessed in the rat nitroglycerine model of facial allodynia and primate capsaicin-induced dermal vasodilation (CIDV) pharmacodynamic model. Cerebrospinal fluid/brain penetration and behavioral effects of chronic dosing and upon withdrawal were evaluated in rats.

RESULTS

Atogepant exhibited high human CGRP receptor-binding affinity and potently inhibited human α-CGRP-stimulated cAMP responses. Atogepant exhibited significant affinity for the amylin1 receptor but lacked appreciable affinities for adrenomedullin, calcitonin and other known neurotransmitter receptor targets. Atogepant dose-dependently inhibited facial allodynia in the rat nitroglycerine model and produced significant CIDV inhibition in primates. Brain penetration and behavioral/physical signs during chronic dosing and abrupt withdrawal were minimal in rats.

CONCLUSIONS

Atogepant is a competitive antagonist with high affinity, potency and selectivity for the human CGRP receptor. Atogepant demonstrated a potent, concentration-dependent exposure/efficacy relationship between atogepant plasma concentrations and inhibition of CGRP-dependent effects.

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.

Central generators of migraine and autonomic cephalalgias as targets for personalized pain management: Translational links

BACKGROUND AND OBJECTIVE

Migraine oscillates between different states in association with internal homeostatic functions and biological rhythms that become more easily dysregulated in genetically susceptible individuals. Clinical and pre-clinical data on migraine pathophysiology support a primary role of the central nervous system (CNS) through 'dysexcitability' of certain brain networks, and a critical contribution of the peripheral sensory and autonomic signalling from the intracranial meningeal innervation. This review focuses on the most relevant back and forward translational studies devoted to the assessment of CNS dysfunctions involved in primary headaches and discusses the role they play in rendering the brain susceptible to headache states.

METHODS AND RESULTS

We collected a body of scientific literature from human and animal investigations that provide a compelling perspective on the anatomical and functional underpinnings of the CNS in migraine and trigeminal autonomic cephalalgias. We focus on medullary, hypothalamic and corticofugal modulation mechanisms that represent strategic neural substrates for elucidating the links between trigeminovascular maladaptive states, migraine triggering and the temporal phenotype of the disease.

CONCLUSION

It is argued that a better understanding of homeostatic dysfunctional states appears fundamental and may benefit the development of personalized therapeutic approaches for improving clinical outcomes in primary headache disorders.

SIGNIFICANCE

This review focuses on the most relevant back and forward translational studies showing the crucial role of top-down brain modulation in triggering and maintaining primary headache states and how these central dysfunctions may interact with personalized pain management strategies.

Advances in the Acute and Preventive Treatment of Pediatric Migraine

PURPOSE OF REVIEW

Headaches are common in children and adolescents. Treatments for debilitating migraine are often not FDA approved or lack evidence of efficacy for children. This narrative review looks at the evidence for acute and preventative pharmacologic and non-pharmacologic treatment of pediatric migraine, as well as reviewing any recent or ongoing clinical trials.

RECENT FINDINGS

Studies have been published on pharmacological treatments for headache, as well as non-pharmacological treatments. Recent findings in pediatric migraine using onabotulinumtoxinA, calcitonin gene related peptide antagonists, interventional procedures, and devices are reviewed. Pharmacologic as well as non-pharmacologic approaches for the prevention and treatment of migraine show safety and efficacy data that is promising. These treatments should be incorporated in a multi-modal approach to the management of pediatric migraine. Continued studies, prospective and randomized, are needed to further assess these newer treatments for migraine in the pediatric setting.

Mode and site of action of therapies targeting CGRP signaling

Targeting CGRP has proved to be efficacious, tolerable, and safe to treat migraine; however, many patients with migraine do not benefit from drugs that antagonize the CGRPergic system. Therefore, this review focuses on summarizing the general pharmacology of the different types of treatments currently available, which target directly or indirectly the CGRP receptor or its ligand. Moreover, the latest evidence regarding the selectivity and site of action of CGRP small molecule antagonists (gepants) and monoclonal antibodies is critically discussed. Finally, the reasons behind non-responders to anti-CGRP drugs and rationale for combining and/or switching between these therapies are addressed.

Atogepant for the preventive treatment of chronic migraine (PROGRESS): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

In this study, we aimed to evaluate the efficacy, safety, and tolerability of atogepant for the preventive treatment of chronic migraine.

METHODS

We did this randomised, double-blind, placebo-controlled, phase 3 trial at 142 clinical research sites across the USA, the UK, Canada, China, Czech Republic, Denmark, France, Germany, Italy, Japan, South Korea, Poland, Russia, Spain, Sweden, and Taiwan. Adults aged 18-80 years with a 1-year or longer history of chronic migraine were randomly assigned (1:1:1) to receive oral atogepant 30 mg twice a day, oral atogepant 60 mg once a day, or placebo. The primary endpoint was change from baseline in mean monthly migraine days (MMDs) across the 12-week treatment period. The primary analysis was done in the modified intent-to-treat population and included all randomly assigned participants who received at least one dose of study intervention, had an evaluable baseline period of electronic diary (eDiary) data, and had at least one evaluable post-baseline 4-week period (weeks 1-4, 5-8, and 9-12) of eDiary data during the double-blind period. The safety population consisted of all participants who received at least one dose of study intervention. This trial is registered with ClinicalTrials.gov (NCT03855137).

FINDINGS

Between March 11, 2019 and Jan 20, 2022, 1489 participants were assessed for eligibility. 711 were excluded, and 778 participants were randomly assigned to atogepant 30 mg twice a day (n=257), atogepant 60 mg once a day (n=262), or placebo (n=259). Participants in the safety population were aged 18-74 years (mean 42·1 years). 459 (59%) of 773 patients were White, 677 (88%) patients were female, and 96 (12%) were male. 84 participants discontinued treatment during the trial, and 755 comprised the modified intent-to-treat population (atogepant 30 mg twice a day n=253, atogepant 60 mg once a day n=256, and placebo n=246). Baseline mean number of MMDs were 18·6 (SE 5·1) with atogepant 30 mg twice a day, 19·2 (5·3) with atogepant 60 mg once a day, and 18·9 (4·8) with placebo. Change from baseline in mean MMDs across 12 weeks was -7·5 (SE 0·4) with atogepant 30 mg twice a day, -6·9 (0·4) with atogepant 60 mg once a day, and -5·1 (0·4) with placebo. Least squares mean difference from placebo was -2·4 with atogepant 30 mg twice a day (95% CI -3·5 to -1·3; adjusted p<0·0001) and -1·8 with atogepant 60 mg once a day (-2·9 to -0·8; adjusted p=0·0009). Most common adverse events for atogepant were constipation (30 mg twice a day 28 [10·9%]; 60 mg once a day 26 [10%]; and placebo 8 [3%]) and nausea (30 mg twice a day 20 [8%]; 60 mg once a day 25 [10%]; and placebo 9 [4%]). Potentially clinically significant weight decrease (≥7% reduction at any time post-baseline) was observed in each treatment group (atogepant 30 mg twice a day 14 [6%]; atogepant 60 mg once a day 15 [6%]; and placebo 5 [2%]).

INTERPRETATION

Atogepant 30 mg twice a day and 60 mg once a day showed clinically relevant reductions in MMDs across 12 weeks in chronic migraine patients. Both atogepant doses were well tolerated, consistent with the known safety profile of atogepant.

FUNDING

Allergan (now AbbVie).

Efficacy and Safety of Anti-calcitonin Gene-Related Peptide (CGRP) Monoclonal Antibodies in Preventing Migraines: A Systematic Review

The neuropeptide calcitonin gene-related peptide (CGRP) is an essential pathophysiological treatment for migraines. A unique class of medications called CGRP monoclonal antibodies target CGRP and its receptor and have demonstrated promising benefits in the treatment and prevention of migraines. This study sought to identify and assess the quality of existing systematic reviews about the effectiveness of CGRP antibodies for preventing migraines, as well as systematically review and synthesize the evidence on these topics. This included the four Food and Drug Administration (FDA)-approved medications erenumab, galcanezumab, fremanezumab, and eptinezumab. The effectiveness and safety of these monoclonal antibodies in preventing migraines should also be examined in light of patient characteristics, and any gaps in the body of knowledge should be noted in order to suggest new lines of investigation. Data gathering included a thorough search of internet databases (PubMed, Cochrane Library, Web of Science, and Scopus) for relevant research released between 2018 and 2023. The findings imply that CGRP monoclonal antibodies are efficient and secure for preventing migraines and may be considered a first-line alternative for treating migraines and drug misuse. The results further imply that combination treatment with CGRP antibodies and onabotulinumtoxinA may enhance the prevention of migraine in adults. With suggestions for more studies to find and address these variables, the significance of genetic and epigenetic factors in the progression of pediatric patients' acute postoperative pain to chronic postsurgical pain is underlined. All four anti-CGRP monoclonal antibodies, erenumab, fremanezumab, galcanezumab, and eptinezumab, were shown to be safe and effective for the prevention of migraine when the research additionally looked at their individual effectiveness and safety. Additionally, the study discovered considerable variances in effectiveness amongst various groups. However, further investigation is required to establish the best time and dosage and the effect of patient characteristics on the effectiveness and safety of these medications.

The vascular role of CGRP: a systematic review of human studies

Intravenous infusion of human alpha calcitonin gene-related peptide (h-α-CGRP) has been applied to explore migraine pathogenesis and cerebral hemodynamics during the past three decades. Cumulative data implicate h-α-CGRP in regulating the vascular tone. In this systematic review, we searched PubMed and EMBASE for clinical studies investigating the vascular changes upon intravenous infusion of h-α-CGRP in humans. A total of 386 studies were screened by title and abstract. Of these, 11 studies with 61 healthy participants and 177 participants diagnosed with migraine were included. Several studies reported hemodynamic effects including flushing, palpitation, warm sensation, heart rate (HR), mean arterial blood pressure (MABP), mean blood flow velocity of middle cerebral artery (mean V_MCA), and diameter of superficial temporal artery (STA). Upon the start of h-α-CGRP infusion, 163 of 165 (99%) participants had flushing, 98 of 155 (63%) participants reported palpitation, and 160 of 165 (97%) participants reported warm sensation. HR increased with 14%-58% and MABP decreased with 7%-12%. The mean V_MCA was decreased with 9.5%-21%, and the diameter of the STA was dilated with 41%-43%. The vascular changes lasted from 20 to >120 min. Intravenous infusion of h-α-CGRP caused a universal vasodilation without any serious adverse events. The involvement of CGRP in the systemic hemodynamic raises concerns regarding long-term blockade of CGRP in migraine patients with and without cardiovascular complications.

Predictors of Response to Fremanezumab in Migraine Patients with at Least Three Previous Preventive Failures: Post Hoc Analysis of a Prospective, Multicenter, Real-World Greek Registry

OBJECTIVE

To define, in a real-world population of patients with high-frequency episodic (HFEM) or chronic migraine (CM), the predictive role of socio-demographic or phenotypic profiling of responders to fremanezumab.

PATIENTS AND METHODS

Two-hundred and four adult fremanezumab-treated patients with either HFEM or CM, who failed to at least three preventive treatments, provided data at baseline on several individual socio-demographic and phenotypic variables. These variables were analyzed for their ability to independently predict the response (50-74% response rates) or super-response (≥ 75% response rates) to fremanezumab. Patients were followed from 3-18 months of fremanezumab exposure.

RESULTS

The main finding to emerge from univariate analyses was that three baseline socio-demographic/clinical variables, i.e., age group 41-70 years (p = 0.02); female gender (p = 0.03); patients with HFEM (p = 0.001), and three clinical phenotypic variables, i.e., strict unilateral pain (p = 0.05); pain in the ophthalmic trigeminal branch (p = 0.04); and the "imploding" quality of pain (p = 0.05), were significantly related to fremanezumab response. However, in multivariate analysis, only HFEM (p = 0.02), the presence of strict unilateral (p = 0.03), and pain location in the ophthalmic trigeminal branch (p = 0.036) were independently associated with good fremanezumab response. Allodynia (p = 0.04) was the only clinical predictive variable of super-responsiveness to fremanezumab.

CONCLUSIONS

A precise phenotypic profiling with identification of pain characteristics consistent with peripheral and/or central sensitization might reliably predict the responsiveness to fremanezumab in migraine prophylaxis.

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.

Calcitonin Gene-Related Peptide and Adrenomedullin Levels During Ictal and Interictal Periods in Patients With Migraine

Background Peptides related to calcitonin gene-related peptide (CGRP) have been suggested to have a role in migraine. Adrenomedullin (AM) might be a candidate molecule because it is related to pain pathways in the peripheral and central nervous systems and uses the same receptors as CGRP. Methodology In this study, we examined the serum CGRP and AM levels during unprovoked ictal and interictal periods of 30 migraine patients as well as 25 healthy controls. Another focus of this study was on the association of CGRP and AM levels with clinical features. Results Mean serum AM levels were 15.80 pg/mL (11.91-21.43 pg/mL) in the ictal and 15.85 pg/mL (12.25-19.29 pg/mL) in the interictal periods in the migraine group and 13.36 pg/mL (10.84-17.18 pg/mL) in the control group. Mean serum CGRP levels were 2.93 pg/mL (2.45-3.90 pg/mL) in the ictal and 3.25 pg/mL (2.85-4.67 pg/mL) in the interictal periods in the migraine group and 3.03 pg/mL (2.48-3.80 pg/mL) in the control group. There were no statistical differences between ictal and/or interictal AM and CGRP levels (p = 0.558 and p = 0.054, respectively) which were also comparable with the results of the control group (p = 0.230, p = 0.295, p = 0.987, p = 0.139, respectively). Ictal serum CGRP and/or AM levels did not correlate with any of the reported clinical features. Conclusions Serum AM and CGRP levels are similar in interictal and unprovoked ictal periods in migraine patients and as well in controls. These results do not indicate that these molecules do not have a role in migraine pathophysiology. Considering the broad mechanisms of action of peptides in the CGRP family, further studies are needed in larger cohorts.

Phase Ib, open-label, fixed-sequence, drug-drug interaction, safety, and tolerability study between atogepant and ubrogepant in participants with a history of migraine

OBJECTIVE

To evaluate potential drug-drug interactions of ubrogepant and atogepant.

BACKGROUND

Ubrogepant and atogepant, calcitonin gene-related peptide (CGRP) receptor antagonists, are recently approved drugs for acute and preventive treatment of migraine, respectively. For patients with migraine who are prescribed atogepant for the preventive treatment of migraine, health care providers could prescribe ubrogepant for the acute treatment of breakthrough migraine attacks.

METHODS

A phase Ib, multi-center, open-label, fixed-sequence study was conducted in participants diagnosed with migraine for at least 1 year. To assess the primary objective of pharmacokinetic interactions in this phase I trial, the highest United States Food and Drug Administration-approved individual dose strengths of atogepant (60 mg once daily) and ubrogepant (100 mg) were utilized, with ubrogepant being administered on a fixed-dose schedule every 3 days, regardless of whether a participant was experiencing a migraine attack. Secondary endpoints included safety and tolerability. Clinical safety measurements were monitored throughout the study.

RESULTS

Of the 31 participants enrolled, 26 completed the study. A single dose of ubrogepant had no statistically significant effect on atogepant pharmacokinetics. Co-administration of ubrogepant with atogepant resulted in a 19% increase (geometric mean ratio 118.80, 90% confidence interval [CI] 108.69-129.84) in the ubrogepant area under the plasma concentration-time curve and a 26% increase (geometric mean ratio 125.63, 90% CI 105.58-149.48) in the ubrogepant maximum plasma concentration. These statistically significant changes in ubrogepant exposure were not clinically meaningful, and no new safety concerns were identified for the combination.

CONCLUSION

The combination use of atogepant and ubrogepant was safe and well tolerated in adult participants with a history of migraine enrolled in the study. Pharmacokinetic changes during co-administration were not clinically meaningful.

Migraine and thyroid dysfunction: Co-occurrence, shared genes and biological mechanisms

BACKGROUND AND PURPOSE

Migraine and thyroid dysfunction, particularly hypothyroidism, are common medical conditions and are known to have high heritability. Thyroid function measures, thyroid stimulating hormone (TSH) and free thyroxine (fT4), are also known to be genetically influenced. Although observational epidemiological studies report an increased co-occurrence of migraine and thyroid dysfunction, a clear and combined interpretation of the findings is currently lacking. A narrative review is provided of the epidemiological and genetic association evidence linking migraine, hypothyroidism, hyperthyroidism and thyroid hormones TSH and fT4.

METHODS

An extensive literature search was conducted in the PubMed database for epidemiological, candidate gene and genome-wide association studies using the terms migraine, headache, thyroid hormones, TSH, fT4, thyroid function, hypothyroidism and hyperthyroidism.

RESULTS

Epidemiological studies suggest a bidirectional relationship between migraine and thyroid dysfunction. However, the nature of the relationship remains unclear, with some studies suggesting migraine increases the risk for thyroid dysfunction whilst other studies suggest the reverse. Early candidate gene studies have provided nominal evidence for MTHFR and APOE, whilst more recently genome-wide association studies have provided robust evidence for THADA and ITPK1 being associated with both migraine and thyroid dysfunction.

CONCLUSIONS

These genetic associations improve our understanding of the genetic relationship between migraine and thyroid dysfunction, provide an opportunity to develop biomarkers to identify migraine patients most likely to benefit from thyroid hormone therapy, and indicate that further cross-trait genetic studies have excellent potential to provide biological insight into their relationship and inform clinical interventions.

Long-term open-label and real-world studies of lasmiditan, ubrogepant, and rimegepant for the acute treatment of migraine attacks

BACKGROUND

Long-term data helps assess the consistency of efficacy, tolerability, and safety of acute treatment over repeated use for different attacks. Real-world studies help assess tolerability, safety, and efficacy in patients with possibly refractory chronic migraine, more comorbidities, other diseases such as cardiovascular diseases, and polypharmacy.

METHODS

This is a narrative review of the long-term open-label and real-world studies of lasmiditan, ubrogepant, and rimegepant for the acute treatment of migraine. Both manuscripts and abstracts were reviewed.

RESULTS

The efficacy and tolerability of lasmiditan, ubrogepant, and rimegepant are maintained over time. No significant cardiovascular adverse events were thought to be related to any of these medications. The rare instances of palpitations and/or tachycardia occurred within 48 hours of lasmiditan. One participant with a history of supraventricular tachycardia had sinus tachycardia thought to be related to ubrogepant which did not recur despite continued use. One case of thrombocytopenia and two cases of increased aspartate aminotransferase and alanine transaminase were thought to be possibly related, but the alanine transaminase and aspartate aminotransferase levels normalized despite continued use of ubrogepant. A case of first-degree atrioventricular block was considered possibly related to rimegepant. Acute use of rimegepant was associated with a decrease in monthly migraine days over time. The three medications were associated with improvement in function and/or productivity.

CONCLUSION

Long-term and real-world data of tolerability, safety and efficacy of lasmiditan, ubrogepant, and rimegepant is thus far consistent with prior studies, but more longitudinal data that clarifies long-term safety as well as consistency and predictors of response is needed.

Effects of Neuropeptides on Dendritic Cells in the Pathogenesis of Psoriasis

Psoriasis is an autoimmune disease that is characterized by discolored, scaled patches of skin. Clinically, it is found that psychological factors often induce or aggravate the disease. Current research suggests that the pathogenesis of psoriasis involves the nervous and immune systems. This article reviews how neuropeptides secreted by nerve fibers affect dendritic cells in psoriasis. In this review, we describe that the neuropeptides calcitonin gene-related peptide, substance P, and vasoactive intestinal peptide can act on dendritic cells and participate in the pathogenesis of psoriasis. These neuropeptides can affect the secretion of interleukin (IL)-12 and IL-23 by dendritic cells, which stimulate T helper (Th)1, Th17, and Th22 cells to produce immune responses and cause the manifestation of psoriasis. The application of neuropeptide inhibitors can improve the skin lesions of psoriasis, which has been confirmed in clinical trials. Therefore, neuroimmune response may be a new direction to develop new drug treatments and perspectives in the development of psoriasis.

Narrative review of migraine management in patients with renal or hepatic disease

OBJECTIVES/BACKGROUND

Treatment of migraine in the setting of either renal or hepatic disease can be daunting for clinicians. Not only does the method of metabolism have to be considered, but also the method of elimination/excretion of the parent drug and any active or toxic metabolites. Furthermore, it is difficult to think about liver or kidney disease in isolation, as liver disease can sometimes contribute to impaired renal function and renal disease can sometimes impair hepatic metabolism, through the cytochrome P450 system.

METHODS

A detailed search for terms related to liver disease, renal disease, and migraine management was performed in PubMed, Ovid Medline, Embase, and the Cochrane Library.For each medication, product labels were retrieved and reviewed using the US FDA website, with additional review of IBM Micromedex, LiverTox, and the Renal Drug Handbook.

RESULTS

This manuscript provides an overview of migraine drug metabolism and how it can be affected by liver and renal impairment. It reviews the standard terminology recommended by the US Food and Drug Administration for the different stages of hepatic and renal failure. The available evidence regarding the use of abortive and preventative medicines in the setting of organ failure is discussed in detail, including more recent therapies such as lasmiditan, gepants, and calcitonin gene-related peptide antibodies.

CONCLUSIONS

For acute therapy, the use of NSAIDS should be limited, as these carry risk for both severe hepatic and renal disease. Triptans can be selectively used, often with dose guideline adjustments. Ubrogepant may be used in severe hepatic disease with dose adjustment and lasmiditan can be used in end stage renal disease. Though non-medicine strategies may be the most reasonable initial approach, many preventative medications can be used in the setting of hepatic and renal disease, often with dose adjustment. This review provides tables of guidelines, including reduced dosing recommendations, for the use of abortive and preventative migraine medications in hepatic and renal failure.

Predictors of response to anti-CGRP monoclonal antibodies: a 24-week, multicenter, prospective study on 864 migraine patients

Background and objectives

The identification of predictors of response to antiCGRP mAbs could favor tailored therapies and personalized treatment plans. This study is aimed at investigating predictors of ≥ 50%, ≥ 75% and 100% response at 24 weeks in patients with high-frequency episodic (HFEM: 8–14 days/month) or chronic migraine (CM).

Methods

This is a large, multicenter, cohort, real-life study. We considered all consecutive adult patients affected by HFEM or CM who were prescribed antiCGRP mAbs for ≥ 24 weeks in 20 headache centers. Patients were interviewed face-to-face using a shared semi-structured questionnaire carefully exploring socio-demographic and clinical characteristics. Patients received subcutaneous erenumab (70 mg or140 mg, monthly), galcanezumab (120 mg monthly, following a 240 mg loading dose), or fremanezumab (225 mg, monthly or 675 mg, quarterly) according to drug market availability, physician’s choice, or patient’s preference. The primary endpoint of the study was the assessment of ≥ 50% response predictors at 24 weeks. Secondary endpoints included ≥ 75% and 100% response predictors at 24 weeks.

Results

Eight hundred sixty-four migraine patients had been treated with antiCGRP mAbs for ≥ 24 weeks (erenumab: 639 pts; galcanezumab: 173 pts; fremanezumab: 55 pts). The ≥50% response (primary endpoint) in HFEM was positively associated with unilateral pain (UP) + unilateral cranial autonomic symptoms (UAs) (OR:4.23, 95%CI:1.57–11.4; p = 0.004), while in CM was positively associated with UAs (OR:1.49, 95%CI:1.05–2.11; p = 0.026), UP + UAs (OR:1.90, 95%CI:1.15–3.16; p = 0.012), UP + allodynia (OR:1.71, 95%CI:1.04–2.83; p = 0.034), and negatively associated with obesity (OR:0.21, 95%CI:0.07–0.64; p = 0.006). The 75% response (secondary endpoint) was positively associated with UP + UAs in HFEM (OR:3.44, 95%CI:1.42–8.31; p = 0.006) and with UP + UAs (OR:1.78, 95%CI:1.14–2.80; p = 0.012) and UP + allodynia (OR:1.92, 95%CI:1.22–3.06; p = 0.005) in CM. No predictor of 100% response emerged in patients with HFEM or CM.

Conclusions

A critical evaluation of headache characteristics indicating peripheral or central sensitization may help in predicting responsiveness to antiCGRP mAbs in HFEM and CM. A more precise pain profiling may represent a steppingstone for a mechanism-based approach and personalized treatment of migraine with compounds targeting specific molecular mechanisms.

Ambient NO2 exposure induces migraine in rats: Evidence, mechanisms and interventions

Migraine is a complex neurological disorder with a high disability rate. Although the precipitating factors of migraine remain unclear, previous studies suggest that when there is excess nitrogen dioxide (NO₂) pollution in the atmosphere, the medical demand due to migraine attacks increases sharply. However, the main role of NO₂ as a trigger for migraine is not yet well understood. The purpose of this study was to explore the relationship between NO₂ exposure and the occurrence of migraine as well as the possible underlying mechanisms. We first investigated whether repeated short-term NO₂ exposure could induce behavioural and biological migraine phenotypes in rats. Next, capsazepine (CZP) was used to block transient receptor potential cation channel subfamily V member 1 (TRPV1) in vivo, and CZP and vitamin E (VE) were used to verify the role of reactive oxygen species (ROS)-TRPV1 signalling in NO₂-induced migraine in primary trigeminal neurones in vitro. We demonstrated that short-term repeated NO₂ exposure can significantly induce migraine in rats, and its key molecular mechanism may be related to ROS burst and its downstream TRPV1 channel activation. The findings of this study will enhance the understanding of the neurotoxic mechanism of NO₂, provide new clues for identifying the aetiology of migraine, and lay a new experimental basis for implementing migraine-related preventive and therapeutic control measures.

A phase IV clinical trial of gastrointestinal motility in adult patients with migraine before and after initiation of a calcitonin gene-related peptide ligand (galcanezumab) or receptor (erenumab) antagonist

OBJECTIVE

To compare effects of an initial dose of calcitonin gene-related peptide (CGRP) monoclonal antibody (mAb) antagonists on gastrointestinal (GI) motility in patients with migraine and to explore if the mechanistic difference contributes to GI adverse events (AEs).

BACKGROUND

Different frequencies of constipation have been observed between CGRP mAbs that target the ligand (galcanezumab [GMB]) or receptor (erenumab [ERE]).

METHODS

Patients (n = 65) with migraine without significant GI symptoms were enrolled in a multi-center, single-blind phase IV clinical trial (NCT04294147) and randomized 1:1 to receive GMB (240 mg; n = 33) or ERE (140 mg; n = 32). GI whole and regional transit times were assessed using a wireless motility capsule 1 week before and 2 weeks after mAb administration. The primary endpoint was change from baseline in colonic transit time (CTT) within each treatment group. Other measures included GI Symptom Rating Scale (GSRS), Bristol Stool Form Scale (BSFS), and spontaneous bowel movement (SBM) evaluation. AEs were monitored throughout the study.

RESULTS

Baseline characteristics indicated significant GI transit time variability with minimal GI reported symptoms. While not statistically significant, a numerical mean increase in CTT was observed in ERE patients (n = 28, mean [SD] at baseline: 33.8 [29.4] h; least square [LS] mean [SE] change: 5.8 [5.7] h, 95% confidence interval [CI] -5.7 to 17.2, p = 0.320), while GMB decreased CTT (n = 31, mean [SD] at baseline: 29.3 [24.5] h; LS mean [SE] change: -5.4 [5.4] h, 95% CI -16.2 to 5.5, p = 0.328) compared to baseline. No meaningful changes were observed in other regional transit times. ERE significantly reduced BSFS (LS mean [SE] score -0.5 [0.2], p = 0.004) and SBM (LS mean [SE] -1.2 [0.5], p = 0.0120), and increased GSRS-constipation compared to baseline (LS mean [SE] score 0.3 [0.1], p = 0.016). GMB increased GSRS-constipation (LS mean [SE] score 0.4 [0.1], p = 0.002). There were no discontinuations due to or serious AEs. A higher percentage of treatment-emergent AEs were reported with ERE than GMB (ERE: nine of 32 [28.1%] versus GMB: three of 33 [9.1%]), with constipation the most frequently reported (ERE: five of 32 [15.6%] versus GMB one of 33 [3.0%]).

CONCLUSION

While the primary endpoint of this study was not met, secondary and tertiary endpoints support a within- and between-treatment change in GI effects suggesting possible mechanistic differences between ligand (GMB) and receptor (ERE) antagonism.

A narrative review of the calcitonin peptide family and associated receptors as migraine targets: Calcitonin gene-related peptide and beyond

OBJECTIVE

To summarize the pharmacology of the calcitonin peptide family of receptors and explore their relationship to migraine and current migraine therapies.

BACKGROUND

Therapeutics that dampen calcitonin gene-related peptide (CGRP) signaling are now in clinical use to prevent or treat migraine. However, CGRP belongs to a broader peptide family, including the peptides amylin and adrenomedullin. Receptors for this family are complex, displaying overlapping pharmacologic profiles. Despite the focus on CGRP and the CGRP receptor in migraine research, recent evidence implicates related peptides and receptors in migraine.

METHODS

This narrative review summarizes literature encompassing the current pharmacologic understanding of the calcitonin peptide family, and the evidence that links specific members of this family to migraine and migraine-like behaviors.

RESULTS

Recent work links amylin and adrenomedullin to migraine-like behavior in rodent models and migraine-like attacks in individuals with migraine. We collate novel information that suggests females may be more sensitive to amylin and CGRP in the context of migraine-like behaviors. We report that drugs designed to antagonize the canonical CGRP receptor also antagonize a second CGRP-responsive receptor and speculate as to whether this influences therapeutic efficacy. We also discuss the specificity of current drugs with regards to CGRP isoforms and how this may influence therapeutic profiles. Lastly, we emphasize that receptors related to, but distinct from, the canonical CGRP receptor may represent underappreciated and novel drug targets.

CONCLUSION

Multiple peptides within the calcitonin family have been linked to migraine. The current focus on CGRP and its canonical receptor may be obscuring pathways to further therapeutics. Drug discovery schemes that take a wider view of the receptor family may lead to the development of new anti-migraine drugs with favorable clinical profiles. We also propose that understanding these related peptides and receptors may improve our interpretation regarding the mechanism of action of current drugs.

Prevention of Migraine

Migraine, a primary headache disorder is a chronic and complex neurological disease that affects millions of people worldwide, impacting their quality of life. It is one of the most common reasons why individuals seek the advice of their physician, and is one of the most common referrals seen in the offices of general neurologists and headache specialists. In the past decade, there has been robust research on not only the pathophysiology of migraine but in the efforts to treat and, importantly, prevent. The introduction of calcitonin gene related peptide antagonists (CGRP-A) have opened new doors for preventive treatment options. OnabotulinumtoxinA (BoNTA) has remained a staple in the treatment of chronic migraine with data emerging with combination therapy. Neurostimulation has offered additional nonpharmacologic approaches to migraine treatment. In addition to lifestyle and behavioral modifications, these have changed the landscape of migraine prevention.

Calcitonin Gene-Related Peptide (CGRP) and Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) in Migraine Pathogenesis

Migraine is a prevalent and debilitating neurologic disorder. Advancements in understanding the underlying pathophysiological mechanisms are spearheading the effort to introduce disease-specific treatment options. In recent years this effort has largely focused on alteration of endogenous neuropeptide signaling, namely the peptides calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP). Human studies into the pathophysiological underpinnings of CGRP and PACAP in migraine are manifold and here we review the works investigating these neuropeptides in patients suffering from migraine in order to elucidate the background for developing new treatment options for this vastly disabling disorder.

New Approaches to Shifting the Migraine Treatment Paradigm

The standard of care paradigm for migraine treatment has been based almost exclusively on approaches that grew out of the happenstance use of market pharmaceuticals. Only methysergide, which has long since been removed from use for safety concerns, the ergotamine family of drugs, and the triptans were explicitly developed with migraine and other vascular headaches in mind. While the forward and innovative thinking to utilize the broad array of agents to treat migraine served millions well, their therapeutic efficacy was often low, and adverse event profiles were troublesome in the least. Advances in biochemical and molecular biology and the application of advanced "designing drugs" methods have brought about a potentially significant shift in treatment. The gepants have efficacies similar to the triptans but without vascular safety or medication overuse concerns. Preventative gepants offer innovative approaches to prevention and efficacy that exceed even the CGRP monoclonal antibodies. Those monoclonal antibodies brought rapid and highly effective outcomes across the spectrum of migraine. They outpaced older oral medication efficacy and eliminated most adverse events while potentially improving compliance with monthly or quarterly dosing. Other serotonin receptors beyond the 5HT1B and1D receptors have been targeted for decades. They now lead us to better formulations of dihydroergotamine for efficacy, convenience, and tolerability, and a 5HT1F-specific acute treatment like the gepants opens new options for acute management. Neuromodulation goes back to the mid-1800's. Our improved understanding of applied biomedical engineering has brought forward several tantalizing devices, including the application of currents distant from the target and patient regulated. Whether these advances change the paradigm of migraine treatment and standards of care remains to be seen, and issues such as cost and patient acceptance will help mold it.

Nitroglycerin as a model of migraine: Clinical and preclinical review

Migraine stands as one of the most disabling neurological conditions worldwide. It is a disorder of great challenge to study given its heterogeneous representation, cyclic nature, and complexity of neural networks involved. Despite this, clinical and preclinical research has greatly benefitted from the use of the nitric oxide donor, nitroglycerin (NTG), to model this disorder, dissect underlying mechanisms, and to facilitate the development and screening of effective therapeutics. NTG is capable of triggering a migraine attack, only in migraineurs or patients with a history of migraine and inducing migraine-like phenotypes in rodent models. It is however unclear to what extent NTG and NO, as its breakdown product, is a determinant factor in the underlying pathophysiology of migraine, and importantly, whether it really does facilitate the translation from the bench to the bedside, and vice-versa. This review provides an insight into the evidence supporting the strengths of this model, as well as its limitations, and shines a light into the possible role of NO-related mechanisms in altered molecular signalling pathways.

A Comprehensive Review of Zavegepant as Abortive Treatment for Migraine

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

From spreading depolarization to epilepsy with neuroinflammation: The role of CGRP in cortex

CGRP release plays a major role in migraine pain by activating the trigeminal pain pathways. Here we explored putative additional effects of CGRP on cortical circuits and investigated whether CGRP affects cortical excitability, cortical spreading depolarization (CSD), a phenomenon associated with migraine aura, blood-brain-barrier (BBB) and microglial morphology. We used immunohistochemistry to localize CGRP and the CGRP receptor (CGRP-R) in native cortex and evaluated morphology of microglia and integrity of the BBB after exposure to CGRP. In anesthetized rats we applied CGRP and the CGRP-R antagonist BIBN4096BS locally to the exposed cortex and monitored the spontaneous electrocorticogram and CSDs evoked by remote KCl pressure microinjection. In mouse brain slices CGRP effects on neuronal activity were explored by multielectrode array. CGRP immunoreactivity was detectable in intracortical vessels, and all cortical neurons showed CGRP-R immunoreactivity. In rat cortex in vivo, topical CGRP induced periods of epileptiform discharges, however, also dose-dependently reduced CSD amplitudes and propagation velocity. BIBN4096BS prevented these effects. CGRP evoked synchronized bursting activity in mouse cortical but not in cerebellar slices. Topical application of CGRP to rat cortex induced plasma extravasation and this was associated with reduced ramification of microglial cells. From these findings we conclude that CGRP induces a pathophysiological state in the cortex, consisting in neuronal hyperexcitability and neuroinflammation Thus, CGRP may have a pronounced impact on brain functions during migraine episodes supporting the benefit of CGRP antagonists for clinical use. However, increased cortical CGRP may end the CSD-induced aura phase of migraine.

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

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

The Anti-CGRP Antibody Fremanezumab Lowers CGRP Release from Rat Dura Mater and Meningeal Blood Flow

Monoclonal antibodies directed against the neuropeptide calcitonin gene-related peptide (CGRP) belong to a new generation of therapeutics that are effective in the prevention of migraine. CGRP, a potent vasodilator, is strongly implicated in the pathophysiology of migraine, but its role remains to be fully elucidated. The hemisected rat head preparation and laser Doppler flowmetry were used to examine the effects on CGRP release from the dura mater and meningeal blood flow of the subcutaneously injected anti-CGRP monoclonal antibody fremanezumab at 30 mg/kg, when compared to an isotype control antibody. Some rats were administered glycerol trinitrate (GTN) intraperitoneally to produce a migraine-like sensitized state. When compared to the control antibody, the fremanezumab injection was followed by reduced basal and capsaicin-evoked CGRP release from day 3 up to 30 days. The difference was enhanced after 4 h of GTN application. The samples from the female rats showed a higher CGRP release compared to that of the males. The increases in meningeal blood flow induced by acrolein (100 µM) and capsaicin (100 nM) were reduced 13–20 days after the fremanezumab injection, and the direct vasoconstrictor effect of high capsaicin (10 µM) was intensified. In conclusion, fremanezumab lowers the CGRP release and lasts up to four weeks, thereby lowering the CGRP-dependent meningeal blood flow. The antibody may not only prevent the released CGRP from binding but may also influence the CGRP release stimulated by noxious agents relevant for the generation of migraine pain.

Characterization of erenumab and rimegepant on calcitonin gene-related peptide induced responses in Xenopus Laevis oocytes expressing the calcitonin gene-related peptide receptor and the amylin-1 receptor

BACKGROUND

The clinical use of calcitonin gene-related peptide receptor (CGRP-R) antagonists and monoclonal antibodies against CGRP and CGRP-R has offered new treatment possibilities for migraine patients. CGRP activates both the CGRP-R and structurally related amylin 1 receptor (AMY1-R). The relative effect of erenumab and the small-molecule CGRP-R antagonist, rimegepant, towards the CGRP-R and AMY-R needs to be further characterized.

METHODS

The effect of CGRP and two CGRP-R antagonists were examined in Xenopus laevis oocytes expressing human CGRP-R, human AMY1-R and their subunits.

RESULTS

CGRP administered to receptor expressing oocytes induced a concentration-dependent increase in current with the order of potency CGRP-R> > AMY1-R > calcitonin receptor (CTR). There was no effect on single components of the CGRP-R; calcitonin receptor-like receptor and receptor activity-modifying protein 1. Amylin was only effective on AMY1-R and CTR. Inhibition potencies (pIC50 values) for erenumab on CGRP induced currents were 10.86 and 9.35 for CGRP-R and AMY1-R, respectively. Rimegepant inhibited CGRP induced currents with pIC50 values of 11.30 and 9.91 for CGRP-R and AMY1-R, respectively.

CONCLUSION

Our results demonstrate that erenumab and rimegepant are potent antagonists of CGRP-R and AMY1-R with 32- and 25-times preference for the CGRP-R over the AMY1-R, respectively. It is discussed if this difference in affinity between the two receptors is the likely reason why constipation is a common and serious adverse effect during CGRP-R antagonism but less so with CGRP binding antibodies.

Drug Safety in Episodic Migraine Management in Adults Part 1: Acute Treatments

PURPOSE OF REVIEW

The aim of this review is to aid in choosing safe options when assessing potential risks of acute migraine treatments based on known mechanisms of action and anticipated safety concerns.

RECENT FINDINGS

Part 1 highlights safety issues associated with commonly used medications to treat acute migraine attacks. Strategies to mitigate cardiovascular and gastrointestinal risks of nonsteroidal anti-inflammatory drugs, evaluation of cardiovascular risks of triptan and ergot alkaloids, and precautions with use of antiemetics and the novel drugs gepants and ditans are discussed to help practitioners in clinical decision-making. When available, we included recommendations from professional societies and data from pharmacovigilance systems. While guidelines on efficacy are available, one must also consider the possible risks and adverse effects of a drug when creating treatment plans.

It is time anti-CGRP monoclonal antibodies be considered first-line prophylaxis for migraine

The result of more than thirty years of research, anti-CGRP monoclonal antibodies are currently the state of the art for migraine preventive therapy. Their efficacy and safety, supported by an already large and growing body of evidence, are added by many other advantages: an early onset of action, favorable posology, negligible pharmacological interaction, and a broad-reaching efficacy in many challenging clinical contexts. When compared to standard prophylactics, these novel medications seem at least as efficacious, clearly more tolerable and, consequently, with a superior adherence profile. Furthermore, recently published analyses indicate that they are cost-effective, especially among those with chronic migraine. Yet, current guidelines endorse their use only after multiple other preventives have failed or have been deemed not tolerable. Although this recommendation may have been sensible at first, the now available data strongly point that time has come for anti-CGRP monoclonal antibodies to be acknowledged as first-line treatments for migraine patients with severe disability. For these individuals, delaying treatment until several other alternatives have failed incurs in significant losses, both economically and to many relevant aspects of their lives.

Adenosine signaling activates ATP-sensitive K+ channels in endothelial cells and pericytes in CNS capillaries

The dense network of capillaries composed of capillary endothelial cells (cECs) and pericytes lies in close proximity to all neurons, ideally positioning it to sense neuron- and glial-derived compounds that enhance regional and global cerebral perfusion. The membrane potential (V_M) of vascular cells serves as the physiological bridge that translates brain activity into vascular function. In other beds, the ATP-sensitive K⁺ (K_ATP) channel regulates V_M in vascular smooth muscle, which is absent in the capillary network. Here, with transgenic mice that expressed a dominant-negative mutant of the pore-forming Kir6.1 subunit specifically in brain cECs or pericytes, we demonstrated that K_ATP channels were present in both cell types and robustly controlled V_M. We further showed that the signaling nucleotide adenosine acted through A_2A receptors and the Gα_s/cAMP/PKA pathway to activate capillary K_ATP channels. Moreover, K_ATP channel stimulation in vivo increased cerebral blood flow (CBF), an effect that was blunted by expression of the dominant-negative Kir6.1 mutant in either capillary cell type. These findings establish an important role for K_ATP channels in cECs and pericytes in the regulation of CBF.

New Insights on Metabolic and Genetic Basis of Migraine: Novel Impact on Management and Therapeutical Approach

Migraine is a hereditary disease, usually one-sided, sometimes bilateral. It is characterized by moderate to severe pain, which worsens with physical activity and may be associated with nausea and vomiting, may be accompanied by photophobia and phonophobia. The disorder can occur at any time of the day and can last from 4 to 72 h, with and without aura. The pathogenic mechanism is unclear, but extensive preclinical and clinical studies are ongoing. According to electrophysiology and imaging studies, many brain areas are involved, such as cerebral cortex, thalamus, hypothalamus, and brainstem. The activation of the trigeminovascular system has a key role in the headache phase. There also appears to be a genetic basis behind the development of migraine. Numerous alterations have been identified, and in addition to the genetic cause, there is also a close association with the surrounding environment, as if on the one hand, the genetic alterations may be responsible for the onset of migraine, on the other, the environmental factors seem to be more strongly associated with exacerbations. This review is an analysis of neurophysiological mechanisms, neuropeptide activity, and genetic alterations that play a fundamental role in choosing the best therapeutic strategy. To date, the goal is to create a therapy that is as personalized as possible, and for this reason, steps forward have been made in the pharmacological field in order to identify new therapeutic strategies for both acute treatment and prophylaxis.

Dialysis headache: characteristics, impact and cerebrovascular evaluation

ABSTRACT Background: Headache is one of the most frequent symptoms that occur during hemodialysis sessions. Despite the high prevalence of dialysis headache, it has been little studied. Objective: To evaluate the characteristics, impact and factors associated with dialysis headache. The behavior of the cerebral vasculature was also compared between patients with and without dialysis headache. Methods: This was a cross-sectional study. Consecutive patients who underwent hemodialysis were assessed through a semi-structured questionnaire, the Headache Impact Test (HIT-6), the Hospital Anxiety and Depression Scale and the Short Form-36 Health Survey (SF-36). Transcranial Doppler ultrasonography was performed in the first and fourth hours of hemodialysis. Results: A total of 100 patients were included; 49 of them had dialysis headache. Women (OR=5.04; 95%CI 1.95-13.04), younger individuals (OR=1.05; 95%CI 1.01-1.08), individuals with higher schooling levels (OR=3.86; 95%CI 1.4-10.7) and individuals who had spent longer times on dialysis programs (OR=0.99; 95%CI 0.98-1) had more dialysis headache (logistic regression). Individuals with dialysis headache had worse quality of life in the domains of pain and general state of health (56.9 versus 76.4, p=0.01; 49.7 versus 60.2, p=0.03, respectively). Dialysis headache was associated with significantly greater impact on life (OR=24.4; 95%CI 2.6-226.6; logistic regression). The pulsatility index (transcranial Doppler ultrasonography) was lower among patients with dialysis headache than among those without them. Conclusions: Dialysis headaches occur frequently and are associated with worse quality of life and patterns of cerebral vasodilatation.

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

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

CGRP and CGRP-receptor as targets of migraine therapy: Brain Prize-2021

BACKGROUND

Migraine is a highly prevalent primary headache with an unclear pathomechanism. During the last 40 years numerous hypotheses have arisen, among them the theory of the trigeminovascular system is the primary one. It serves as a skeleton in successful preclinical studies and in the development of effective therapeutic options for migraine headache.

OBJECTIVE

The Brain Prize (awarded annually by the Lundbeck Foundation) is the most prestigious tribute in neuroscience. The winners in 2021 were Lars Edvinsson, Peter Goadsby, Michael Moskowitz and Jes Olesen. They are the fathers of the migraine pathomechanism which led to revolutionary new treatments. This review summarizes their landmark findings.

METHODS

Data related to this topic were reviewed from PubMed records published between 1979 and May 2021. Searches were based on preclinical and clinical studies in the covered field. The findings were listed in chronological order. From a therapeutic perspective, only randomized controlled trials and meta-analysis were discussed.

RESULTS

The calcitonin gene-related peptide-related pathogenesis of migraine is based on the activation of the trigeminovascular system. The therapeutic triad for migraine is triptans, gepants and calcitonin gene-related peptide-targeted monoclonal antibodies.

CONCLUSION

In the past 40 years, the systematic work of leading headache scientists has resulted in robust theoretical and therapeutic knowledge in the preclinical and clinical study of migraine.

Identification of disease- and headache-specific mediators and pathways in migraine using blood transcriptomic and metabolomic analysis

BACKGROUND

Recent data suggest that gene expression profiles of peripheral white blood cells can reflect changes in the brain. We aimed to analyze the transcriptome of peripheral blood mononuclear cells (PBMC) and changes of plasma metabolite levels of migraineurs in a self-controlled manner during and between attacks.

METHODS

Twenty-four patients with migraine were recruited and blood samples were collected in a headache-free (interictal) period and during headache (ictal) to investigate disease- and headache-specific alterations. Control samples were collected from 13 age- and sex-matched healthy volunteers. RNA was isolated from PBMCs and single-end 75 bp RNA sequencing was performed using Illumina NextSeq 550 instrument followed by gene-level differential expression analysis. Functional analysis was carried out on information related to the role of genes, such as signaling pathways and biological processes. Plasma metabolomic measurement was performed with the Biocrates MxP Quant 500 Kit.

RESULTS

We identified 144 differentially-expressed genes in PBMCs between headache and headache-free samples and 163 between symptom-free patients and controls. Network analysis revealed that enriched pathways included inflammation, cytokine activity and mitochondrial dysfunction in both headache and headache-free samples compared to controls. Plasma lactate, succinate and methionine sulfoxide levels were higher in migraineurs while spermine, spermidine and aconitate were decreased during attacks.

CONCLUSIONS

It is concluded that enhanced inflammatory and immune cell activity, and oxidative stress can play a role in migraine susceptibility and headache generation.

Time course of efficacy of atogepant for the preventive treatment of migraine: Results from the randomized, double-blind ADVANCE trial

Background

Atogepant is an oral, small-molecule, calcitonin gene–related peptide receptor antagonist for the preventive treatment of migraine.

Methods

In the double-blind, phase 3 ADVANCE trial, participants with 4–14 migraine days/month were randomized to atogepant 10 mg, 30 mg, 60 mg, or placebo once daily for 12 weeks. We evaluated the time course of efficacy of atogepant for the preventive treatment of migraine. Analyses included change from baseline in mean monthly migraine days during each of the three 4-week treatment periods, change in weekly migraine days during weeks 1–4, and proportion of participants with a migraine on each day during the first week.

Results

We analyzed 873 participants (n = 214 atogepant 10 mg, n = 223 atogepant 30 mg, n = 222 atogepant 60 mg, n = 214 placebo). For weeks 1–4, mean change from baseline in mean monthly migraine days ranged from −3.1 to −3.9 across atogepant doses vs −1.6 for placebo (p < 0.0001). For weeks 5–8 and 9–12, reductions in mean monthly migraine days ranged from −3.7 to −4.2 for atogepant vs −2.9 for placebo (p ≤ 0.012) and −4.2 to −4.4 for atogepant vs −3.0 for placebo (p < 0.0002), respectively. Mean change from baseline in weekly migraine days in week 1 ranged from −0.77 to −1.03 for atogepant vs −0.29 with placebo (p < 0.0001). Percentages of participants reporting a migraine on post-dose day 1 ranged from 10.8% to 14.1% for atogepant vs 25.2% with placebo (p ≤ 0.0071).

Conclusion

Atogepant demonstrated treatment benefits as early as the first full day after treatment initiation, and sustained efficacy across each 4-week interval during the 12-week treatment period.

Clinical trial registration: ClinicalTrials.gov identifier: NCT03777059

Periorbital Nociception in a Progressive Multiple Sclerosis Mouse Model Is Dependent on TRPA1 Channel Activation

Headaches are frequently described in progressive multiple sclerosis (PMS) patients, but their mechanism remains unknown. Transient receptor potential ankyrin 1 (TRPA1) was involved in neuropathic nociception in a model of PMS induced by experimental autoimmune encephalomyelitis (PMS-EAE), and TRPA1 activation causes periorbital and facial nociception. Thus, our purpose was to observe the development of periorbital mechanical allodynia (PMA) in a PMS-EAE model and evaluate the role of TRPA1 in periorbital nociception. Female PMS-EAE mice elicited PMA from day 7 to 14 days after induction. The antimigraine agents olcegepant and sumatriptan were able to reduce PMA. The PMA was diminished by the TRPA1 antagonists HC-030031, A-967079, metamizole and propyphenazone and was absent in TRPA1-deficient mice. Enhanced levels of TRPA1 endogenous agonists and NADPH oxidase activity were detected in the trigeminal ganglion of PMS-EAE mice. The administration of the anti-oxidants apocynin (an NADPH oxidase inhibitor) or alpha-lipoic acid (a sequestrant of reactive oxygen species), resulted in PMA reduction. These results suggest that generation of TRPA1 endogenous agonists in the PMS-EAE mouse model may sensitise TRPA1 in trigeminal nociceptors to elicit PMA. Thus, this ion channel could be a potential therapeutic target for the treatment of headache in PMS patients.

Could erectile dysfunction be a side effect of CGRP inhibition? A case report

Background

Recently, antimigraine drugs targeting the calcitonin gene-related peptide pathway have been approved for clinical use as preventive migraine medication.

Case report

We present a case of a 54-year-old male migraine patient, who reported erectile dysfunction as a possible side effect of treatment with galcanezumab, a monoclonal antibody targeting calcitonin gene-related peptide. His potency recovered after treatment discontinuation.

Discussion

As calcitonin gene-related peptide is involved in mammalian penile erection, erectile dysfunction is a conceivable side effect associated with calcitonin gene-related peptide inhibition. Postmarketing surveillance will elucidate the actual incidence of erectile dysfunction in patients using these new antimigraine drugs, and determine whether a causal relationship between calcitonin gene-related peptide inhibition and erectile dysfunction exists. This would be relevant not only because of the direct sexual consequences of erectile dysfunction, but also considering the potential cardiovascular consequences of calcitonin gene-related peptide (receptor) blockade and the association of both migraine and erectile dysfunction with cardiovascular disease.

Conclusion

Erectile dysfunction might be an overlooked, but reversible side effect in male migraine patients using monoclonal antibodies that inhibit the calcitonin gene-related peptide pathway, including galcanezumab. This paper may raise clinical awareness and suggest that this potential side effect needs to be studied further.

Development and Application of a Transcriptomic Signature of Bioactivation in an Advanced In Vitro Liver Model to Reduce Drug-induced Liver Injury Risk Early in the Pharmaceutical Pipeline

Early risk assessment of drug-induced liver injury (DILI) potential for drug candidates remains a major challenge for pharmaceutical development. We have previously developed a set of rat liver transcriptional biomarkers in short-term toxicity studies to inform the potential of drug candidates to generate a high burden of chemically reactive metabolites that presents higher risk for human DILI. Here, we describe translation of those NRF1-/NRF2-mediated liver tissue biomarkers to an in vitro assay using an advanced micropatterned coculture system (HEPATOPAC) with primary hepatocytes from male Wistar Han rats. A 9-day, resource-sparing and higher throughput approach designed to identify new chemical entities with lower reactive metabolite-forming potential was qualified for internal decision making using 93 DILI-positive and -negative drugs. This assay provides 81% sensitivity and 90% specificity in detecting hepatotoxicants when a positive test outcome is defined as the bioactivation signature score of a test drug exceeding the threshold value at an in vitro test concentration that falls within 3-fold of the estimated maximum drug concentration at the human liver inlet following highest recommended clinical dose administrations. Using paired examples of compounds from distinct chemical series and close structural analogs, we demonstrate that this assay can differentiate drugs with lower DILI risk. The utility of this in vitro transcriptomic approach was also examined using human HEPATOPAC from a single donor, yielding 68% sensitivity and 86% specificity when the aforementioned criteria are applied to the same 93-drug test set. Routine use of the rat model has been adopted with deployment of the human model as warranted on a case-by-case basis. This in vitro transcriptomic signature-based strategy can be used early in drug discovery to derisk DILI potential from chemically reactive metabolites by guiding structure-activity relationship hypotheses and candidate selection.

High rates of (treated) hypothyroidism among chronic migraine patients consulting a specialized headache clinic: are we missing something?

BACKGROUND

Roughly three percent of episodic migraine patients evolve into the most burdensome chronic form of this condition every year. While some of the determinants behind this transformation are well established, others are still ill defined. Hypothyroidism is a prevalent endocrinological disorder that can both produce a secondary headache or aggravate a pre-existing primary headache disorder such as migraine.

OBJECTIVE

We aimed to re-assess the association between hypothyroidism and chronic migraine controlling for factors such as hormone replacement treatment status and bodyweight.

METHODS

We retrospectively analyzed the medical records of episodic and chronic migraine patients who consecutively consulted our headache clinic in order to determine the prevalence of adequately treated hypothyroidism in each group. Only patients receiving a stable dose regimen were included. The body mass index and other possibly confounding covariates were also collected.

RESULTS

Data from 111 migraine patients was included for analysis. Most (88.6%) of chronic migraine sufferers were overusing acute medication. Treated hypothyroidism was significantly more prevalent in chronic migraine patients (29.55%) compared to episodic migraine patients (8.96%). This association was independent of the patients' body mass index or other variables.

CONCLUSION

Alterations of neuronal metabolism, deficient calcitonin release, or focal inflammation causing local hormonal deactivation might explain why hypothyroidism, in spite of levothyroxine replacement therapy, is associated with migraine chronification. Further studies evaluating these factors are warranted.

Efficacy and safety of fremanezumab in patients with episodic and chronic migraine with documented inadequate response to 2 to 4 classes of migraine preventive medications over 6 months of treatment in the phase 3b FOCUS study

Background

Fremanezumab, a fully humanized monoclonal antibody (IgG2Δa) selectively targets the calcitonin gene-related peptide and has proven efficacy for the preventive treatment of migraine. In this study, we evaluated the long-term efficacy, safety, and tolerability of monthly and quarterly fremanezumab.

Methods

Episodic migraine and chronic migraine patients completing the 12-week double-blind period of the FOCUS trial entered the 12-week open-label extension and received 3 monthly doses of fremanezumab (225 mg). Changes from baseline in monthly migraine days, monthly headache days of at least moderate severity, days of acute headache medication use, days with photophobia/phonophobia, days with nausea or vomiting, disability scores, and proportion of patients achieving a ≥50% or  ≥75% reduction in monthly migraine days were evaluated.

Results

Of the 807 patients who completed the 12-week double-blind treatment period and entered the open-label extension, 772 patients completed the study. In the placebo, quarterly fremanezumab, and monthly fremanezumab dosing regimens, respectively, patients had fewer average monthly migraine days (mean [standard deviation] change from baseline: − 4.7 [5.4]; − 5.1 [4.7]; − 5.5 [5.0]), monthly headache days of at least moderate severity (− 4.5 [5.0]; − 4.8 [4.5]; − 5.2 [4.9]), days per month of acute headache medication use (− 4.3 [5.2]; − 4.9 [4.6]; − 4.8 [4.9]), days with photophobia/phonophobia (− 3.1 [5.3]; − 3.4 [5.3]; − 4.0 [5.2]), and days with nausea or vomiting (− 2.3 [4.6]; − 3.1 [4.5]; − 3.0 [4.4]). During the 12-week open-label extension, 38%, 45%, and 46% of patients, respectively, achieved a ≥50% reduction and 16%, 15%, and 20%, respectively, achieved a ≥75% reduction in monthly migraine days. Disability scores were substantially improved in all 3 treatment groups. There were low rates of adverse events leading to discontinuation (<1%).

Conclusion

Fremanezumab demonstrated sustained efficacy up to 6 months and was well tolerated in patients with episodic migraine or chronic migraine and documented inadequate response to multiple migraine preventive medication classes.

Trial registration

ClinicalTrials.gov NCT03308968 (FOCUS).

A narrative review of the importance of pharmacokinetics and drug-drug interactions of preventive therapies in migraine management

Objective

To review the pharmacokinetics of major classes of migraine preventives and the clinical implications of drug–drug interactions (DDIs) with the use of these therapies in migraine management.

Background

Preventive treatments for migraine are recommended for a large proportion of patients with frequent migraine attacks. These patients often exhibit a number of comorbidities, which may lead to the introduction of multiple concomitant therapies. Potential DDIs must be considered when using polytherapy to avoid increased risk of adverse events (AEs) or inadequate treatment of comorbid conditions.

Methods

A literature search was performed to identify pharmacokinetic properties and potential DDIs of beta‐blockers, antiepileptic drugs, antidepressants, calcium channel blockers, gepants, and monoclonal antibody therapies targeting the calcitonin gene‐related peptide pathway with medications that may be used for comorbid conditions.

Results

Most DDIs occur through alterations in cytochrome P450 isoenzyme activity and may be complicated by genetic polymorphism for metabolic enzymes. Additionally, drug metabolism may be altered by grapefruit juice ingestion and smoking. The use of migraine preventive therapies may exacerbate symptoms of comorbid conditions or increase the risk of AEs associated with comorbid conditions as a result of DDIs.

Conclusions

DDIs are important to consider in patients with migraine who use multiple medications. The development of migraine‐specific evidence‐based preventive treatments allows for tailored clinical management that reduces the risk of DDIs and associated AEs in patients with comorbidities.