Gepants - a long way to cure: a narrative review

Voltage-gated Calcium Channels as Potential Therapeutic Targets in Migraine

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

Drug effects on neuropeptides and their receptors: Big hopes but moderate success in the treatment of chronic pain

Neuropeptides, including tachykinins, CGRP, and somatostatin, are localized in a peptidergic subgroup of nociceptive primary afferent neurons. Tachykinins and CGRP are pronociceptive, somatostatin is an antinociceptive mediator. Intensive drug research has been performed to develop tachykinin and CGRP antagonists, and somatostatin agonists as analgesics. CGRP receptor antagonists are efficacious and well-tolerated drugs in migraine. Monoclonal antibodies against CGRP or its receptor are used for the prophylactic treatment of migraine. Tachykinin NK1 receptor antagonists failed as analgesics but are used for chemotherapy-induced nausea and vomiting. New, orally active somatostatin 4 receptor agonists are promising drug candidates for treating various pain conditions.

[CGRP: from neuropeptide to the therapeutic target (background and pathophysiology)]

Calcitonin gene-related peptide (CGRP) plays a pivotal role in migraine pathophysiology. The importance of CGRP in migraine became evident from numerous clinical studies investigating CGRP levels both interictally and ictally and reports on the efficacy of CGRP-based migraine therapies. In this paper, the above mentioned studies will be presented and the reader will be introduced to the development of CGRP-based medication. Finally, current study results on CGRP receptor antagonists, the so-called gepants, will be presented.

Reduced hepatic impairment study to evaluate pharmacokinetics and safety of zavegepant and to inform dosing recommendation for hepatic impairment

Zavegepant, a high-affinity, selective, small-molecule calcitonin gene-related peptide (CGRP) receptor antagonist, is approved in the United States for acute treatment of migraine in adults. The effects of moderate hepatic impairment (8 participants with Child-Pugh score 7-9 points) on the pharmacokinetics of a single 10-mg intranasal dose of zavegepant versus eight matched participants with normal hepatic function were evaluated in a phase I study. Pharmacokinetic sampling determined total and unbound plasma zavegepant concentrations. Moderate hepatic impairment increased the exposure of total zavegepant (~2-fold increase in AUC0-inf and 16% increase in Cmax) versus normal hepatic function, which is not considered clinically meaningful. The geometric least squares mean ratios (moderate impairment/normal) of plasma zavegepant AUC0-inf and Cmax were 193% (90% confidence interval [CI]: 112, 333; p = 0.051) and 116% (90% CI: 69, 195; p = 0.630), respectively. The geometric mean fraction unbound of zavegepant was similar for participants with moderate hepatic impairment (0.13; coefficient of variation [CV] 13.71%) versus those with normal hepatic function (0.11; CV 21.43%). Similar exposure findings were observed with unbound zavegepant versus normal hepatic function (~2.3-fold increase in AUC0-inf and 39% increase in Cmax). One treatment-emergent adverse event (mild, treatment-related headache) was reported in a participant with normal hepatic function. No dosage adjustment of intranasal zavegepant is required in adults with mild or moderate hepatic impairment.

Revolutionizing migraine management: advances and challenges in CGRP-targeted therapies and their clinical implications

Migraine, a prevalent neurological disorder, affects approximately 14.1% of the global population and disproportionately impacts females. This debilitating condition significantly compromises quality of life, productivity, and incurs high healthcare costs, presenting a challenge not only to individuals but to societal structures as a whole. Despite advances in our understanding of migraine pathophysiology, treatment options remain limited, necessitating ongoing research into effective therapies. This review delves into the complexity of migraine management, examining the roles of genetic predisposition, environmental influences, personalized treatment approaches, comorbidities, efficacy and safety of existing acute and preventive treatments. It further explores the continuum between migraine and tension-type headaches and discusses the intricacies of treating various migraine subtypes, including those with and without aura. We emphasize the recent paradigm shift toward trigeminovascular activation and the release of vasoactive substances, such as calcitonin gene-related peptide (CGRP), which offer novel therapeutic targets. We assess groundbreaking clinical trials, pharmacokinetic and pharmacodynamic perspectives, safety, tolerability, and the real-world application of CGRP monoclonal antibodies and gepants. In the face of persisting treatment barriers such as misdiagnosis, medication overuse headaches, and limited access to specialist care, we discuss innovative CGRP-targeted strategies, the high cost and scarcity of long-term efficacy data, and suggest comprehensive solutions tailored to Turkiye and developing countries. The review offers strategic recommendations including the formulation of primary care guidelines, establishment of specialized outpatient clinics, updating physicians on novel treatments, enhancing global accessibility to advanced therapies, and fostering patient education. Emphasizing the importance of lifestyle modifications and holistic approaches, the review underscores the potential of mass media and patient groups in disseminating critical health information and shaping the future of migraine management.

Concentration-QTc and cardiac safety analysis of single and multiple zavegepant nasal spray doses in healthy participants to support approval

Zavegepant is a novel gepant administered as a nasal spray approved in the United States at a 10 mg dose for the acute treatment of migraine with or without aura in adults. The cardiovascular safety of zavegepant nasal spray was assessed in both single-ascending dose (SAD) and multiple-ascending dose (MAD) studies in healthy participants. The SAD study included 72 participants (54 active/18 placebo) who received 0.1-40 mg zavegepant or placebo. The MAD study included 72 participants (56 active/16 placebo) who received 5-40 mg zavegepant or placebo for 1-14 days. Plasma zavegepant pharmacokinetics and electrocardiographic (ECG) parameters (Fridericia-corrected QT interval [QTcF], heart rate, PR interval, ventricular depolarization [QRS], T-wave morphology, and U-wave presence) were analyzed pre- and post-zavegepant administration. Using pooled data from the SAD and MAD studies, the relationship between time-matched plasma zavegepant concentrations and QTc interval was assessed using a linear mixed-effects model to evaluate the potential for QTc interval prolongation. Results showed that single and multiple doses of zavegepant had no significant impact on ECG parameters versus placebo, and there was no concentration-dependent effect on QTcF interval. The estimated slope of the plasma zavegepant concentration-QTcF model was -0.053 ms per ng/mL with a 90% confidence interval of -0.0955 to -0.0110 (p = 0.0415), which is not considered clinically meaningful. At doses up to four times the recommended daily dose, zavegepant does not prolong the QT interval to any clinically relevant extent.

Acute Treatment of Migraine: Expert Consensus Statements from the United Arab Emirates (UAE)

INTRODUCTION

Migraine, characterized by recurrent headaches and often accompanied by other symptoms like nausea, vomiting, and sensitivity to light and sound, significantly impacts patients' quality of life (QoL) and daily functioning. The global burden of migraines is reflected not only in terms of reduced QoL but also in the form of increased healthcare costs and missed work or school days. While UAE (United Arab Emirates)-specific consensus-based recommendations for the effective use of preventive calcitonin gene-related peptide (CGRP)-based migraine therapies have been published previously, an absence of such regional guidance on the management of acute migraine represents a gap that needs to be urgently addressed.

METHODS

A task force of eight neurologists from the UAE with expertise in migraine management conducted a comprehensive literature search and developed a set of expert statements on the management of acute migraine that were specific to the UAE context. To ensure diverse perspectives are considered, a Delphi panel comprising 16 neurologists plus the task force members was set up. Consensus was achieved using a modified Delphi survey method. Consensus was predefined as a median rating of 7 or higher without discordance (if > 25% of the Delphi panelists rate an expert statement as 3 or lower on the Likert scale). Expert statements achieving consensus were adopted.

RESULTS

The Modified Delphi method was used successfully to achieve consensus on all nine expert statements drafted by the task force. These consensus statements aim to provide a comprehensive guide for UAE healthcare professionals in treating acute migraine. The statements cover all aspects of acute migraine treatment, including what goals to set, the timing of treatment, treatment strategy to use in case of inadequate response to triptans, safety aspects of combining gepants for acute attacks with preventive CGRP-based therapies, special population (pregnant and pediatric patients) considerations, and the management of the most bothersome symptoms (MBS).

CONCLUSIONS

Adopting these consensus statements on the treatment of acute migraine can help enhance patient care, improve outcomes, and standardize treatment practices in the UAE. The collaborative effort of experts with diverse experiences in developing these consensus statements will strengthen the credibility and applicability of these statements to various healthcare settings in the country.

Update on gepants for the treatment of chronic migraine

Chronic migraine (CM) is a profoundly debilitating condition that has detrimental clinical and social outcomes. Over the past two decades, novel small-molecule calcitonin gene-related peptide (CGRP) receptor antagonists, known as gepants, and CGRP monoclonal antibodies (mAbs) have been developed, ushering in a new era of migraine-specific treatment. In this review, we discuss the literature investigating the role of gepants for the treatment of CM. Numerous completed and ongoing clinical studies have conclusively demonstrated the safety, tolerability, and efficacy of several gepants for the acute treatment of migraine. However, preventive trials involving gepants have focused on patients with episodic migraine, with atogepant being the only gepant approved for CM prevention by the US Food and Drug Administration at the time of writing. Although some preliminary positive results have been reported, further research is still required to achieve additional advancements in the future. In summary, the effectiveness of gepants for treating individuals with CM are highly expected. This review highlights the development and current progress of gepants for the treatment of CM, focusing both on their role as acute abortive agents and preventive measures and on their concomitant use with other antimigraine medications, such as CGRP mAbs or triptans.

Real-world effectiveness of Anti-CGRP monoclonal antibodies compared to OnabotulinumtoxinA (RAMO) in chronic migraine: a retrospective, observational, multicenter, cohort study

BACKGROUND

Chronic migraine (CM) is a disabling condition with high prevalence in the general population. Until the recent approval of monoclonal antibodies targeting the calcitonin gene-related peptide (Anti-CGRP mAbs), OnabotulinumtoxinA (BoNT-A) was the only treatment specifically approved for CM prophylaxis. Direct comparisons between the two treatments are not available so far.

METHODS

We performed an observational, retrospective, multicenter study in Italy to compare the real-world effectiveness of Anti-CGRP mAbs and BoNT-A. Patients with CM who had received either treatment according to Italian prescribing regulations were extracted from available clinical databases. Efficacy outcomes included the change from baseline in monthly headache days (MHD), MIgraine Disability ASsessment test (MIDAS), and monthly acute medications (MAM) evaluated at 6 and 12 months of follow-up. The primary outcome was MHD change from baseline at 12 months. Safety outcomes included serious adverse events (SAE) and treatment discontinuation. Unadjusted and adjusted models were used for the analyses.

RESULTS

Two hundred sixteen potentially eligible patients were screened; 183 (86 Anti-CGRP mAbs; 97 BoNT-A) were included. One hundred seventy-one (80 Anti-CGRP mAbs; 91 BoNT-A) and 154 (69 Anti-CGRP mAbs; 85 BoNT-A) patients were included in the efficacy analysis at 6 and 12 months of follow-up, respectively. Anti-CGRP mAbs and BoNT-A both resulted in a mean MHD reduction at 6 (-11.5 and -7.2 days, respectively; unadjusted mean difference -4.3; 95%CI -6.6 to -2.0; p = 0.0003) and 12 months (-11.9 and -7.6, respectively; unadjusted mean difference -4.4; 95%CI -6.8 to -2.0; p = 0.0002) of follow-up. Similar results were observed after adjusting for baseline confounders. Anti-CGRP mAbs showed a significant MIDAS (-31.7 and -19.2 points, p = 0.0001 and p = 0.0296, respectively) and MAM reduction (-5.1 and -3.1 administrations, p = 0.0023 and p = 0.0574, respectively) compared to BoNT-A at 6 and 12 months. No SAEs were reported. One patient receiving fremanezumab discontinued treatment due to arthralgia. Treatment discontinuations, mainly for inefficacy, were comparable.

CONCLUSION

Both Anti-CGRP mAbs and BoNT-A were effective in CM patients with Anti-CGRP mAbs presenting higher effect magnitude, with comparable safety. Still, BoNT-A remains a valuable option for CM patients with contraindications to Anti-CGRP mAbs or for frail categories who are candidates to local therapy with limited risk of systemic administration.

Migraine Comorbidities

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

Eptinezumab for the Prevention of Migraine: Clinical Utility, Patient Preferences and Selection - A Narrative Review

The new Calcitonin Gene-Related Peptide (CGRP)-targeted therapies have proven high efficacy and tolerability in episodic and chronic migraine. Eptinezumab is a humanized monoclonal antibody that selectively binds CGRP with high affinity. Eptinezumab was approved by the Food and Drug Administration on February 21st, 2020, for the preventive treatment of migraine in adults. It is administered intravenously over 30 minutes with a standard dose of 100 mg and has a T-max of 30 minutes-1 hour and a half-life of 27 days. These pharmacological properties allow for a very rapid onset of effect and a quarterly administration. It is the first time that a preventive treatment for migraine can be offered as an intravenous administration. As the range of therapeutic possibilities in migraine is expanding, the treatment process must include common decision-making, where physicians should explain in detail to patients the different characteristics of treatment options beyond efficacy and side effects. Patients can now express a preference on a range of opportunities: pharmacological versus non-pharmacological approaches, route of administration, frequency of administration, efficacy, rapidity, side effects, costs, the possibility of titration or dosing, and durability of effectiveness at suspension. Also, patient preferences can be influenced by age, country, migraine severity, and earlier experience with CGRP-targeted therapies. Besides, adherence may be influenced by several factors, including route and the schedule of administration. This narrative review describes a new perspective from the patient's point of view. Clinicians should ally with patients to select treatments that meet each patient's needs and thus apply a tailored approach, addressing not only headaches. In this way, physicians would care for the patients globally and stand out their preferences on different aspects of treatment. Besides, healthcare professionals shall be aware that patients' beliefs about therapies are subject to change with increasing experience with new therapeutic approaches.

Towards precision medicine in migraine: Recent therapeutic advances and potential biomarkers to understand heterogeneity and treatment response

After 35 years since the introduction of the International Classification of Headache Disorders (ICHD), we are living in the era of the second great revolution in migraine therapies. First, discoveries of triptans provided a breakthrough in acute migraine treatment utilizing bench-to-bedside research results on the role of serotonin in migraine. Next, the discovery of the role of neuropeptides, more specifically calcitonin gene-related peptide (CGRP) in migraine attack led to the development of anti-CGRP therapies that are effective both in acute and preventive treatment, and are also able to reduce migraine-related burden. Here, we reviewed the most recent clinical studies and real-world data on available migraine-specific medications, including triptans, ditants, gepants and anti-CGRP monoclonal antibodies. Novel drug targets, such as PACAP and amylins were also discussed. To address the main challenges of migraine therapy, the high heterogeneity of people with migraine, the prevalent presence of various comorbid disorders, and the insufficient medical care of migraine patients were covered. Promising novel approaches from the fields of omics, blood and saliva biomarker, imaging and provocation studies might bring solutions for these challenges with the potential to identify further drug targets, distinguish more homogeneous patient subgroups, contribute to more optimal drug selection strategies, and detect biomarkers in association with headache features or predicting treatment efficacy. In the future, the combined analysis of data of different biomarker modalities with machine learning algorithms may serve precision medicine in migraine treatment.

Calcitonin Gene-Related Peptide Systemic Effects: Embracing the Complexity of Its Biological Roles-A Narrative Review

The calcitonin gene-related peptide (CGRP) is a neuropeptide widely distributed throughout the human body. While primarily recognized as a nociceptive mediator, CGRP antagonists are currently utilized for migraine treatment. However, its role extends far beyond this, acting as a regulator of numerous biological processes. Indeed, CGRP plays a crucial role in vasodilation, inflammation, intestinal motility, and apoptosis. In this review, we explore the non-nociceptive effects of CGRP in various body systems, revealing actions that can be contradictory at times. In the cardiovascular system, it functions as a potent vasodilator, yet its antagonists do not induce arterial hypertension, suggesting concurrent modulation by other molecules. As an immunomodulator, CGRP exhibits intriguing complexity, displaying both anti-inflammatory and pro-inflammatory effects. Furthermore, CGRP appears to be involved in obesity development while paradoxically reducing appetite. A thorough investigation of CGRP's biological effects is crucial for anticipating potential side effects associated with its antagonists' use and for developing novel therapies in other medical fields. In summary, CGRP represents a neuropeptide with a complex systemic impact, extending well beyond nociception, thus offering new perspectives in medical research and therapeutics.

A Brief Review of Gepants

PURPOSE OF REVIEW

Gepants are small molecules that antagonize calcitonin gene-related peptide (CGRP) receptors. Due to their favorable side effect profile and versatility in treating headaches acutely and preventively, gepants are preferred over triptans. We will cover the indications for the four FDA-approved gepants in adults: rimegepant, atogepant, ubrogepant, and zavegepant. This review will illustrate how gepants will continue to revolutionize the acute and preventive treatment of headaches.

RECENT FINDINGS

Gepants are now available in oral tablet, dissolving tablet, and intra-nasal spray formulations. Recent studies have shown promising utility in treating the pre-headache or prodromal phase. They have favorable tolerability, no evidence for association with medication overuse, and remain a safer alternative in those who have cerebrovascular risk factors. Additional research is needed to explore occurrence of Raynaud's phenomenon in participants treated with gepants, as it has been associated with CGRP monoclonal antibodies, but are not extensively studied in gepants. Gepants are expected to play a significant role in the next generation of migraine treatments.

Calcitonin Gene-Related peptide receptor antagonist suppresses allergic asthma responses via downregulation of group 2 innate lymphoid cells in mice

Allergic asthma is caused by chronic inflammation and hyper-responsiveness of the airway and is thought to be mediated by adaptive T helper type 2 (Th2)-driven immunity. However, recent studies have demonstrated that neuropeptide calcitonin gene-related peptide (CGRP)-mediated activation of group 2 innate lymphoid cells (ILC2s) may contribute to the development of asthma pathogenesis. Here, we investigated the therapeutic effects of the systemic administration of rimegepant, a CGRP receptor antagonist, on allergic asthma. Hyperplasia of CGRP-immunoreactive pulmonary neuroendocrine cells (PNECs) was observed in ovalbumin (OVA)-induced asthmatic mice. Concomitant with this, we observed an increase in the content of total lung CGRP. Upon antigen challenge, the concentration of plasma CGRP was transiently upregulated, whereas CGRP immunoreactivity within PNECs was intensively downregulated, suggesting that PNECs were the most likely source of CGRP. When rimegepant was administered according to CGRP kinetics, it suppressed asthma phenotypes, including airway hyper-responsiveness, infiltration of inflammatory cells in bronchoalveolar lavage fluid (BALF), hyperplasia of mucus-producing cells, and production of the Th2 cytokine IL-5. Moreover, we observed a decrease in the number of ILC2s and their capacity for IL-5 release in the presence of IL-33 in rimegepant-treated mice. In the allergic asthma model, rimegepant suppressed the activation of ILC2s mediated by PNEC-derived CGRP and subsequently impaired adaptive Th2-driven immunity, which ameliorated asthmatic phenotypes. Thus, an anti-CGRP signal strategy to target ILC2 will be a novel and attractive approach for treating allergic asthma that is refractory to other treatments.

Gel-forming antagonist provides a lasting effect on CGRP-induced vasodilation

Migraine affects ∼15% of the adult population, and the standard treatment includes the use of triptans, ergotamines, and analgesics. Recently, CGRP and its receptor, the CLR/RAMP1 receptor complex, have been targeted for migraine treatment due to their critical roles in mediating migraine headaches. The effort has led to the approval of several anti-CGRP antibodies for chronic migraine treatment. However, many patients still suffer continuous struggles with migraine, perhaps due to the limited ability of anti-CGRP therapeutics to fully reduce CGRP levels or reach target cells. An alternative anti-CGRP strategy may help address the medical need of patients who do not respond to existing therapeutics. By serendipity, we have recently found that several chimeric adrenomedullin/adrenomedullin 2 peptides are potent CLR/RAMP receptor antagonists and self-assemble to form liquid gels. Among these analogs, the ADE651 analog, which potently inhibits CLR/RAMP1 receptor signaling, forms gels at a 6-20% level. Screening of ADE651 variants indicated that residues at the junctional region of this chimeric peptide are important for gaining the gel-forming capability. Gel-formation significantly slowed the passage of ADE651 molecules through Centricon filters. Consistently, subcutaneous injection of ADE651 gel in rats led to the sustained presence of ADE651 in circulation for >1 week. In addition, analysis of vascular blood flow in rat hindlimbs showed ADE651 significantly reduces CGRP-induced vasodilation. Because gel-forming antagonists could have direct and sustained access to target cells, ADE651 and related antagonists for CLR/RAMP receptors may represent promising candidates for targeting CGRP- and/or adrenomedullin-mediated headaches in migraine patients.